PAETE.ORG FORUMS
Paetenians Home on the Net

HOME | ABOUT PAETE | USAP PAETE MUNISIPYO  | MEMBERS ONLY  | PICTORIAL PAETE | SINING PAETE  | LINKS  |

FORUM GUIDELINES
please read before posting

USAP PAETE Forum Index USAP PAETE
Discussion Forums for the people of Paete, Laguna, Philippines
 
 FAQFAQ   SearchSearch    UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

(Health) Dengue Viruses

 
Post new topic   Reply to topic   printer-friendly view    USAP PAETE Forum Index -> Science Lessons Forum
View previous topic :: View next topic  
Author Message
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Thu Mar 30, 2006 8:20 am    Post subject: (Health) Dengue Viruses Reply with quote






Rice University
29 March 2006

Simple idea to dramatically improve dengue vaccinations

Multi-site vaccinations could protect against all four dengue viruses
HOUSTON, March 29, 2006 -- An innovative new study explains, for the first time, the failure of previous attempts to vaccinate against the four known Dengue viruses, and it suggests a very simple solution – injecting the four vaccines simultaneously at different locations on the body.
A mosquito-born disease, Dengue kills tens of thousands of people per year and sickens 100 million more. Known as "bone-break disease," Dengue is characterized by excruciating pain and was "the most important mosquito-borne viral disease affecting humans" in 2005 according to the U.S. Centers for Disease Control.

The study, from bioengineers and physicists at Rice University, appears in the March 24 issue of the journal Vaccine. The study suggests that the multi-site vaccination strategy, termed polytopic vaccination, may be effective against other diseases as well, including HIV and cancer.

Dengue infection occurs from one of four closely related viruses. Previous exposure to one of the four – either by prior infection or by vaccination – makes people significantly more likely to develop a potentially lethal hemorrhagic infection if they are later infected by one of the other three viruses.

"This is a classic case of something called 'original antigenic sin,' which happens when our immune system becomes overly reliant upon memory when recognizing diseases similar to those that it has seen before," said lead researcher Michael Deem, the John W. Cox Professor in Biochemical and Genetic Engineering and professor of physics and astronomy. "With diseases like HIV, influenza and Dengue, our acquired immune system's tendency to go-with-what-it-knows can leave us more vulnerable to infection from a mutant strain or a related virus. The immune system may respond less favorably in these cases than if it had never been exposed to the disease in the first place."

Original antigenic sin, or immunodominance, arises out of the procedure the immune system uses to target infection. This starts when the immune system identifies infected cells and brings pieces of them into the lymph node for targeting. Within a few days of infection, the immune system completes a massive scan of the 100 million available T-cells in its arsenal. Through a complex trial-and-error process, it identifies three to five T-cells that best recognize and attack the components of the sickened cells. Once the cells are selected, they are produced by the millions and sent out to clear the infection. After the infection is gone, thousands of these pre-programmed T-cells remain in the body, lying in wait should the disease return.

In recent years, public health officials have documented the disturbing co-existence of two or more Dengue viruses in Brazil, Cuba, Thailand, and other tropical and subtropical countries. Because sequential infection by multiple Dengue viruses can lead to increased likelihood of deadly infections, public health officials have attempted to counter the threat of co-existent versions of Dengue by developing a vaccine against all four versions simultaneously. Doctors found that patients who got a four-component vaccine wound up only being protected against one or two versions at most, due to immunodominance.

Intrigued by these results, Deem and graduate student Hao Zhou developed a precise computer model of the immune system's biochemical scanning process to see if they could recreate the effect and find out what caused it. Their program conducts statistical calculations about the likelihood of specific interactions at the atomic level. They conducted trillions of calculations and gradually built up a bigger picture of what occurs in Dengue immunodominance.

"When faced with more than one version of the virus, the immune system may respond preferentially against the version for which it has T-cells with the strongest affinity, which is immunodominance," Deem said.

He said polytopic vaccination – giving different vaccines simultaneously at different locations on the body – could help overcome immunodominance by taking advantage of the relative isolation of lymph nodes throughout the body. Each person has hundreds of lymph nodes. Deem believes vaccinations at four different sites, served by four different lymph nodes, could allow the body to simultaneously develop immune responses against all four versions of Dengue.

"The literature about immunodominance is new and growing," Deem said. "Ours is the first model that can predict immunodominance, and when we compare our results with experimental data from Dengue vaccination trials, they match quite closely. There may be other factors at work, but we appear to be explaining a significant portion of the effect that occurs in Dengue immunodominance."

Immunodominance is also a problem for researchers working on vaccines for both the AIDS virus and cancer, each of which mutate quickly and occur in multiple strains.


###
The research is supported by the National Institutes of Health and the National Science Foundation.

*************************************************************

Questions to explore further this topic:

What is dengue?

http://www.doh.gov.ph/healthadvisories/dengue
http://www.cdc.gov/ncidod/dvbid/dengue/
http://www.cdc.gov/ncidod/dvbi.....gue-qa.htm
http://www.who.int/mediacentre...../fs117/en/
http://www.who.int/csr/resourc.....001-11.pdf
http://www.dhpe.org/infect/dengue.html
http://www.niaid.nih.gov/factsheets/dengue.htm
http://phoenity.com/diseases/dengue.html
http://www.searo.who.int/en/Se.....ion522.htm

How is dengue transmitted?

http://www.liquidjigsaw.com/animation/anim0c.htm

How does a virus replicate?

http://www.liquidjigsaw.com/animation/anim5.htm

How does the dengue virus replicate?

http://www.who.int/tdr/disease.....al_rep.htm

Where is dengue common?

http://www2.ncid.cdc.gov/trave.....dengue.htm

How is dengue diagnosed?

http://www.who.int/csr/resourc.....012-23.pdf
http://www.who.int/csr/resourc.....034-47.pdf

How is dengue treated?

http://www.who.int/csr/resourc.....001-11.pdf

How is dengue controlled?

http://www.who.int/csr/resourc.....048-59.pdf
http://www.who.int/csr/resourc.....060-66.pdf
http://www.who.int/csr/resourc.....067-69.pdf

Avoiding mosquitoes

http://www.cyh.com/HealthTopic.....mp;id=2222

Dengue in the Philippines

http://www.doh.gov.ph/NEC/dengue/dusept2005.pdf
http://depts.washington.edu/ei.....;print=837
http://depts.washington.edu/ei.....;print=729

What are ovitraps?

http://www.searo.who.int/en/se.....2_2536.htm


What is a dengue vaccine?

http://www.who.int/vaccine_res.....ml#vaccine
http://w3.whosea.org/EN/Sectio.....2_2515.htm
http://www.pdvi.org/PDFs/artic.....review.pdf

The Four Dengue Viruses

http://w3.whosea.org/LinkFiles.....7_ch12.pdf
http://jcm.asm.org/cgi/content/full/43/11/5784

A lecture on Dengue research

http://www.nyas.org/ebriefreps.....layer.html

What is the problem with a second infection of Dengue?

http://www.nature.com/nm/journ.....3-820.html

What is immunodominance?

http://www.rice.edu/sallyport/.....t/flu.html
http://en.wikipedia.org/wiki/O.....igenic_sin
http://www.37c.com.cn/topic/00.....uno/07.htm
http://www.jem.org/cgi/content/abstract/124/3/331
http://jvi.asm.org/cgi/content/abstract/76/9/4251
http://www.mwdeem.rice.edu/mwdeem/perspective.pdf

Child-invented educational game on dengue

http://w3.whosea.org/LinkFiles.....chap26.pdf

GAMES

http://www.solutions-site.org/kids/learn1.htm


Last edited by adedios on Sat Jan 27, 2007 4:47 pm; edited 2 times in total
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Mon Jun 05, 2006 3:23 pm    Post subject: Dengue Awareness Month Reply with quote

Dengue Awareness Month
Manila Bulletin
6 June 2006

DENGUE Fever Awareness Month is observed in June every year. This month is indeed the best time to remind the public about dengue fever because it is the onset of the rainy season, when outbreaks of the disease usually occur. Dengue fever, a mosquitoborne disease that is endemic in the Philippines affects thousands of Filipinos, mostly children, and accounts for scores of deaths every year. Last year, more than 10,000 dengue fever patients were admitted in government hospitals all over the country. This figure will surely be equaled, if not surpassed this year, unless the public observes preventive measures against the disease.


Dengue fever is caused by a virus that is transmitted to humans by the Aedes mosquito, a small black mosquito with white dots on its back and head and white stripes on its legs, which bites during the day. This mosquito breeds in every possible place where there is stagnant water.

The signs and symptoms of dengue fever, which appear three to 15 days after the bite of an infective mosquito, include fever that lasts five to seven days, headache, loss of appetite, abdominal pain, joint and muscle pains, and a skin rash. Usually, the disease is a mild, self-limiting illness, but the severe form of the illness, known as dengue hemorrhagic fever or H-fever, which is characterized by bleeding that usually involves the gastrointestinal tract, skin, and nervous system, is life-threatening.

The best way to prevent the spread of dengue fever is by eliminating all possible breeding places of its mosquito vector. Within their neighborhood, people must fill potholes; cover water containers and septic tanks; not allow empty cans, soft drink bottles, old tires, etc. to accumulate water; ensure that drains and gutters are not clogged and that water flows freely in sewage lines; and dispose of garbage properly and regularly.

Additionally, people should protect themselves against the Aedes mosquito by: Screening their house or using mosquito nets, mosquito repellants, and/or mosquito coils and mats; and isolating persons with dengue fever in a screened room for at least five days from the onset of the symptoms.
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Mon Jul 31, 2006 3:43 pm    Post subject: UGA study explains peaks and troughs of dengue epidemics Reply with quote

University of Georgia
28 July 2006

UGA study explains peaks and troughs of dengue epidemics

Athens, Ga. -- Scientists have long known that epidemics of dengue fever wax and wane over a period of several years, but they've never been quite sure why. With the incidence and range of the potentially deadly mosquito-borne illness increasing, understanding the factors that influence these epidemics has never been more important.

A new study by researchers at the University of Georgia suggests that a brief period of cross-immunity conferred by any one of the four viral strains, or serotypes, that cause dengue explains the timing of epidemics.

"We found that since about the mid 1980s, there's been a sequential replacement of the dominant serotype," said lead author Helen Wearing, a post-doctoral researcher at the UGA Institute of Ecology. "So, for example, one year serotype three is 60 percent of the cases and the next year serotype two is dominant and so on. Epidemics of individual serotypes recur every eight to 10 years, but, at the same time, if you look at all the data together, you see about an average three-year cycle with some seasonal component to it."

In addition to helping resolve a long-standing debate in public health, the study, published this week in the early online edition of the journal Proceedings of the National Academy of Sciences, gives researchers a framework that can be used to create models that predict dengue outbreaks in both space and time.

"It's a framework that highlights the key elements you need to take into account while developing a forecasting model," Wearing said. "Because if you were to build a forecasting model without understanding the trends in cross-immunity, you would not necessarily predict what we observe."

The researchers examined 30 years of data from the government of Thailand and from a Thai clinic that keeps what is widely regarded as the most comprehensive set of data on dengue. Southeast Asia has been a dengue hot spot since the 1950s, but the researchers note that their model applies to other regions where all four dengue strains circulate.

The researchers compared the data with results from mathematical models that explore – both independently and collectively – the role factors such as temporary cross-immunity and variation in serotype virulence play in epidemics. They found that cross-immunity alone is enough to create the patterns that are observed in nature.

The study is a major departure from other theories about what drives dengue epidemics. The conventional wisdom is that an amplification of the severity of disease caused by repeat infections with different strains, a phenomenon known as antibody-dependent enhancement, drives the boom and bust cycles of dengue epidemics.

"Temporary cross-immunity has been ignored by the epidemiological community," said study co-author Pejman Rohani, associate professor of ecology and UGA Biomedical and Health Sciences Institute researcher.

"It's discussed in the scientific literature," Wearing added, "but no one ever considers it an important factor in generating the epidemiological cycles."

Cross-immunity, which lasts from two to nine months, results when overall antibody levels created by the body in response to infection by one serotype are high enough to protect against infection by related serotypes. After this period, however, antibody levels drop to levels that are no longer neutralizing but instead are exploited by the dengue virus to enhance replication and cause more severe illness.

"You can't deny the empirical fact that people who get severe dengue may well have had cases before," Rohani said. "But our work suggests it's not the mechanism that's underlying the big-picture pattern that we see."

Several factors are contributing to an increase in dengue epidemics. Global warming is allowing the species primarily responsible for spreading dengue (Aedes aegypti, also known as the yellow fever mosquito) to expand its range. Population growth in developing nations is pushing more people into substandard housing in mosquito-infested areas. And the ease of travel brings the virus to areas that were previously dengue-free when a mosquito bites an infected traveler and then spreads it to others. According to the Centers for Disease Control and Prevention, Aedes aegypti and the related Aedes albopictus (the Asian tiger mosquito) have the potential to spread dengue in sporadic outbreaks in the Southern and Southeastern United States.

Rohani said the same modeling techniques he and Wearing used to study dengue can help shed light on the transmission of other multi-strain diseases such as cholera, malaria and influenza. He calls a better understanding of such diseases, "one of the most important issues in public health and epidemiology in general."

"Until now, it's been very much a single-host, single-pathogen type of framework," Rohani said. "Now with avian influenza being very much on everyone's mind, we're beginning to realize that the genetic diversity of infectious agents is really important."
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Tue Aug 15, 2006 8:52 am    Post subject: DepEd raises alert on dengue Reply with quote

DepEd raises alert on dengue


By Alcuin Papa, Edson C. Tandoc Jr.
Inquirer
Last updated 06:56pm (Mla time) 08/14/2006


(UPDATE) THE Department of Education (DepEd) has raised the alert on dengue hemorrhagic fever after a teenager reportedly died of the disease in Marikina City on Monday.

The alert also followed the result of the Weekly Disease Surveillance Report of the Department of Health (DoH) showing that dengue fever remains second on the list of common diseases during the rainy season.

It has been reported that a teenager from Nangka, Marikina City Monday died of dengue, according to relatives.

But Marikina City health officer Alberto Herrera would not categorically declare that the cause of the student's death was dengue fever but he said it was a "suspected dengue case."

He said they had already sent teams to the school and to the village of Marikina Heights to educate people about dengue as well as oversee cleanup operations.

Herrera was quick to say however that residents and students need not panic as the case was just "incidental."

Education Secretary Jesli Lapus has directed school administrators to mobilize their own health personnel to disseminate information on the prevention and control of the said disease.

Dengue is an acute infectious viral disease usually affecting infants and young children. It is characterized by fever during the initial phase with other symptoms like headache, pain in the eye, joint pain, muscle pain and followed by signs of bleeding particularly from the nose and gums.

The education department said schools are also ordered to closely collaborate with the Parent-Teachers Community Associations (PTCAs), local government units, municipal health officers in referring students and teachers with symptoms of dengue fever.
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Tue Mar 27, 2007 7:58 am    Post subject: Severe dengue infections may go unrecognized in internationa Reply with quote

Infectious Diseases Society of America
26 March 2007

Severe dengue infections may go unrecognized in international travelers

Severe cases of a common travelers' infection may not be recognized if doctors rely on the World Health Organization's (WHO) guidelines for identifying it, according to a new study published in the April 15 issue of The Journal of Infectious Diseases, now available online.

Dengue is the most important emerging disease among international travelers, with a 30-fold increase in incidence over the past 50 years worldwide. Like malaria, dengue is transmitted to humans by mosquitoes.

Most cases are mild. Symptoms include fever, rash, headache, pain behind the eyes, and muscle and joint pain. According to the WHO, dengue hemorrhagic fever (DHF) is characterized by fever, low platelet count, clinical evidence of leaking capillaries, and spontaneous bleeding or fragile blood vessels. The most serious cases can lead to shock and death. There is no cure for dengue infection, but management of the disease's effects can prevent the worst outcomes.

The study, conducted by Ole Wichmann, MD, MCTM, DTM&H, at the Robert Koch Institute in Berlin, Germany, and colleagues throughout Europe, collected data through the European Network on Surveillance of Imported Diseases at 14 sites in 8 European countries.

Out of more than 200 patients treated for dengue infection at these sites over two years, less than 1 percent fit all four criteria necessary to meet the WHO definition of DHF. However, 11 percent had at least one manifestation of severe dengue disease, and a total of 23 percent required hospitalization due to dengue-related symptoms.

"Dengue exists more as a continuous spectrum," Dr. Wichmann said. "Severe disease can be present in patients who do not fulfill all four DHF criteria."

"The term 'dengue hemorrhagic fever' puts undue emphasis on bleeding," he added, noting that plasma leakage and shock can occur without it. "Clinicians who mainly focus on bleeding...may miss the most important conditions that require hospitalization and treatment."

Their findings also showed that travelers who acquire a second dengue infection are more at risk for severe cases of dengue, although some patients had severe symptoms when infected during their first trip to a dengue-endemic country.

It is becoming more and more crucial that health care providers understand the clinical spectrum of dengue and its diagnosis. "Given the increase in business travel and other travel, and the global spread of dengue fever, these findings have important implications for the future burden of severe imported dengue infections," Wichmann said. "It will also be of great interest to business and leisure travelers, and expatriates, who have experienced one dengue infection and are concerned about this risk of returning to a dengue endemic area."

As a next step to their study Wichmann highlighted the need for more inquiry into a clinical definition of dengue. "In order to perform more uniform surveillance and research, including vaccine trials, studies are urgently needed to establish new and more robust definitions for severe dengue."

###
Founded in 1904, The Journal of Infectious Diseases is the premier publication in the Western Hemisphere for original research on the pathogenesis, diagnosis, and treatment of infectious diseases; on the microbes that cause them; and on disorders of host immune mechanisms. Articles in JID include research results from microbiology, immunology, epidemiology, and related disciplines. It is published under the auspices of the Infectious Diseases Society of America (IDSA). Based in Alexandria, Va., IDSA is a professional society representing more than 8,000 physicians and scientists who specialize in infectious diseases.
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Fri May 18, 2007 7:27 am    Post subject: Genome of yellow fever/dengue fever mosquito sequenced Reply with quote

Virginia Tech
17 May 2007

Genome of yellow fever/dengue fever mosquito sequenced

Half of genome consists of transposable elements, characterized by team lead by Virginia Tech
Blacksburg, Va. -- Developing new strategies to prevent and control yellow fever and dengue fever has become more possible with the completion of the first draft of the genome sequence of Aedes aegypti mosquito by scientists led by Vishvanath Nene at The Institute for Genomic Research (TIGR) and David Severson at the University of Notre Dame. The genome is the complete set of genetic material including genes and other segments of DNA in an organism.

The research appears in the May 18, 2007 Science Express, in the article, "Genome Sequence of Aedes aegypti, A Major Arbovirus Vector." Researchers at 24 universities and other institutions worldwide contributed to the effort.

Among the co-authors are members of the Vector-Borne Infectious Disease Research Group at Virginia Tech (www.vectorborne.ibphs.vt.edu), Zhijian (Jake) Tu, associate professor in the Department of Biochemistry (www.biochem.vt.edu); James K Biedler, biochemistry postdoctoral associate; Song Li, research specialist senior in biochemistry; and Monique Royer Coy, biochemistry graduate student; and Chunhong Mao, senior project associate with the Virginia Bioinformatics Institute at Virginia Tech.

Tu coordinated efforts with TIGR and five research laboratories in the United States, Spain, and France to annotate transposable elements (TEs) in the Ae. aegypti genome. TEs are segments of nucleic acids, or genetic material, that move around the genome and have a significant impact on its structure and size.

Also, Jinsong Zhu, assistant professor of biochemistry at Virginia Tech, who was a senior researcher at the University of California, Riverside, is involved in this process that has so far validated about 80 percent of the 15,419 predicted protein coding genes in Ae. aegypti. He explains, "An important part of this project is gene annotation which predicts numbers and locations of mosquito genes in the genome. In parallel to sequencing DNA in chromosomes, scientists have also sequenced large amounts of messenger RNAs collected from different mosquito tissues at distinct developmental stages. Matching a messenger RNA to a predicted gene will validate authenticity of this gene."

The TE team, lead by the Tu laboratory, uncovered and described more than 1,000 transposable elements, which occupy approximately 50 percent of the entire Ae. aegypti genome. For example, a transposable element named Feilai has more than 50,000 copies interspersed in the genome. By comparison, Anopheles gambiae, the malaria mosquito genome is probably less than 25 percent TEs. The Ae. aegypti genome is five times the size of the malaria mosquito genome.

"Although the majority of protein coding TE copies in Ae. aegypti appear to be degenerate, a significant number of elements have potentially active TE copies, indicating that they may be developed as tools for genetic studies of mosquitoes," Tu said.

"If you look at the genome as an ecological system, TEs are different lineages that co-evolve with the rest of the genome" said Tu. "They evolve different relationships with the genome. Some are genetic parasites; they appear to do nothing except replicate within the genome. Others are used by the host -- the individual organism's genetic machinery --to perform biological functions."

TEs may be developed as genetic tools to study the interaction between mosquitoes and pathogens, and thus may lead to controls of transmission of disease, Tu said. Control might take the form of a genetic control, such as using TEs to carry a gene into the genome that would make the mosquito resistant to the virus and stop its role as a vector for disease. Although that scenario is challenging, the payoff is potentially great, Tu said.

"By introducing TEs in a more or less random way to see what happens to the laboratory mosquitoes, the TEs become a tool to study the genetic mechanism of mosquito-virus interaction, to help us understand mosquito biology and reveal new ways to interfere with disease transmission," Tu said.

According to the article in Science Express, the general failure to date of conventional disease prevention strategies for most mosquito-borne pathogens provides a strong incentive to explore and develop novel control strategies that efficiently disrupt the transmission cycle or enhance existing strategies. The Ae. aegypti genome sequence is expected to stimulate efforts to elucidate interactions at the molecular level between mosquitoes and the pathogens they transmit to humans.

###
TEs uncovered in the course of the research were classified and filed in TEfam, a central database established by the Tu lab for submission, retrieval, and analysis of TEs. The database was designed and implemented by Mao at Virginia Bioinformatics Institute. It is available at http://TEfam.biochem.vt.edu

Members of the TE team are listed at the TEfam site.

Tu's lab is also working on mosquitoes that carry Malaria. Tu’s lab was part of the group that annotated the genome of the Malaria mosquito in 2002.

Tu's work on characterization and organization of transposable elements in mosquito genomes has been funded by the National Institutes of Health since his arrival at Virginia Tech in 1999.

There are currently a number of laboratories at Virginia Tech that work on different ways to control vector-borne infectious diseases ( http://www.vectorborne.ibphs.vt.edu ).
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Sat Jun 16, 2007 2:12 pm    Post subject: Local govts can help beat dengue Reply with quote

Local govts can help beat dengue

By Julia M. Fabon, Researcher

Local governments can play a big role in combating a potential dengue outbreak. Take the case of the Manila Health Department (MHD), which is actively implementing strategies adopted from the national health program to prevent an outbreak of dengue fever and dengue hemorrhagic fever in the city.

Prevention programs include clearing and clean-up operations to remove possible breading sites of mosquitoes, clearing of waterways, and defogging operations, according to Dr. Ed Serrano, head of MHD’s Preventable Diseases Section.

Dengue is infectious and considered communicable. There is no specific treatment for it yet, which partly explains the high mortality rate of its victims.

Dr. Ed Serrano said the MHD is implementing four major strategies in the antidengue prevention program: ensuring environmental sanitation; self-protection methods; use of chemicals to kill mosquitoes in the communities; and community health education.

To promote environmental sanitation, a 4 o’clock habit has been initiated. As early as 4 a.m., communities conduct clean-up operations in the breeding sites for mosquitoes to prevent their use as habitats of these nefarious insects. It is known as the search and destroy component of the antidengue program.

The self-protection strategy refers to encouraging people to wear long sleeves, pants and using insect repellant lotion on the skin to avoid mosquito bites. People are also encouraged to seek early consultation with a physician within three days of the onset of fever to diagnose if an individual is positive or negative from dengue.

While defogging operations had been conducted, people are enjoined to say no to indiscriminate fogging. Fogging should never be conducted unless there is a known case of dengue in a barangay.

The chemical prevention method makes use of insecticides in killing larvae (or larviciding), fogging or fumigation, and larvitrapping.

In larviciding, chemicals are mixed with water and sprinkled on possible breeding places to destroy mosquito larvae. Manila initiates insect environmental control in places with plenty of mosquitoes through spraying water-based insecticides, and diesel-based insecticides in defogging. Barangays prefer the latter.

Larvitrapping is conducted in places where there are only few known dengue cases. This is done by burying or planting cans painted black on the outside. The cans are half-filled with water and a stick made of lawanit, a kind of special plywood, is dipped into the water. After seven days, the sticks are pulled out to measure mosquito larvae. Upon computing the larvae trapping index, those with 10 and above are considered high risk areas, where the mosquito population is dense, and a dengue outbreak is possible in that barangay. In this case, preventive measures are taken immediately.

Health education is conducted constantly, mostly with the use of informative educational materials given in seminars. Sanitation officers visit barangays weekly, while health education promotion officers (HEPOs) conduct barangay visits every two weeks. If there are requests from the schools or barangays, community visits are done more frequently.

Since these are day-biting mosquitoes, the areas possibly affected by dengue-carrying mosquitoes may not be easily distinguished. Thus, a holistic approach in controlling mosquitoes through simultaneous application of the different prevention methods is applied. For instance, if a child from Barangay 1 who studying in School A is traced to be a dengue victim, it is difficult to identify where the mosquitoes came from. In this case, immediate /prompt prevention measures are simultaneously are conducted in the communities that cover barangay and school.

The study of current age trends of dengue victims in Manila show that many of the affected are from aged 15 to 45, and working or employed. Through weekly monitoring, it has been found that some cases are those of the lone known case in the barangay, which may mean that the infection of the victim happened outside the barangay limits.

Another case to consider, is if a city is seriously implementing prevention program and the other is not so serious to do so. Such cases provides limitations to implement the holistic approach of prevention.

Dr. Serrano stressed that environmental prevention is superior over all the other types of dengue prevention measures. It is everybody’s responsibility, and requires concerted efforts of the families in the barangay. Simply cleaning our houses and streets can prevent dengue. The power ton control dengue is in the hands of the people.

Dengue Awareness Month

The Times’ associate paper, Panay News, reports that a campaign to raise public awareness of dengue fever and remind the public to observe preventive measures against it is being carried out by various rural health units in Capiz which is observing Dengue Awareness Month this June.

“The reminder is mainly on cleanliness of the surroundings, especially with the onset of the rainy season,” said Dr. Jarvis Punsalan, Capiz integrated provincial health officer.

The local health authorities remind the public to conduct clean-up campaigns, cover water drums and pails, replace water in flower vases, clean all water containers as well as gutters of leaves and debris, dispose properly of all containers that can hold stagnant water, and dispose of old tires or puncture tires used as roof support, among others, to prevent mosquitoes from breeding.

The Department of Health’s (DOH) National Center for Disease Prevention and Control will also intensify its “Tepok Lamok, Dengue Sapok” program and will conduct surveillance, monitoring, follow up of dengue cases, and information and education campaigns.

The health department encourages the observance of the “4-S four-mula” against dengue: Search and destroy, Self-protection measures, Seek early consultation and Say no to indiscriminate fogging unless there is an outbreak and to be observant of the symptoms of the disease like the sudden onset of high fever, headache, vomiting, abdominal pain, nose and gum bleeding, and skin rashes.

The public is also advised to report to the nearest health center all suspected dengue cases.

Dengue has been considered by the DOH as an all-year round disease which rises in incidence during the rainy season due to presence of more breeding places for disease-causing aedes aegypti type of mosquitoes.
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Sat Jun 16, 2007 2:13 pm    Post subject: Dengue fever epidemic Reply with quote

Dengue fever epidemic

By Katrice R. Jalbuena Reporter

Now that the rainy season has come, the mosquito population has increased and the threat of a dengue fever epidemic is again in sight.

There has actually been a decrease in dengue cases reported nationwide—and the problem appears to be remarkable only in Negros Occidental because of the rise in cases and the recent deaths there.

Still, the Department of Health (DOH) has raised a serious nationwide warning against dengue and dengue hemorrhagic fever, viral-infection diseases spread by mosquitoes.

One thing to remember: Contrary to public belief, dengue is a year-round disease.

“We need to stress how deadly this disease can be,” Health Secretary Francisco T. Duque 3rd, said. “The rainy season has started, which means that there are increased breeding sites for dengue mosquitoes. But it is not just during the rainy season that dengue cases are reported. Contrary to popular belief, dengue is a disease that afflicts people all year round.”

35,000 cases

According to the records of the Department of Health, last year the annual total of dengue cases was around 35,000 cases. Of these, 350 were confirmed fatalities.

These number do not include unconfirmed reports or take into consideration cases that were not reported or recorded by the health authorities.

Duque noted that to keep these mosquitoes away, the public must regularly clean their surroundings and get rid of items like used tires and empty cans that hold stagnant water—the breeding ground of dengue mosquitoes.

Records show that from January to May 2007, the DOH’s National Epidemiology Center had recorded a total of 5,436 dengue cases nationwide. This is 16.2 percent lower than 6,482 cases registered during the same period last year. But it is still a high figure.

NCR has the most

Metro Manila accounted for 1,244 cases; followed by the Calabarzon region with 743 cases; Central Visayas with 622 cases; Southern Mindanao with 567 cases and Northern Min-danao with 444 cases.

Is the high count in Metro Manila because it has a larger population than the other regions? Or is it because dengue cases in the regions are under-reported?

From January to March of this year, 32 people have died according to the official DOH figures.

Just this week, 28 cases were reported from a town in southern Negros Occidental. Three of the dengue-afflicted patients have died.

Health officials are encouraging anyone who has a recurring fever for two or three days to immediately have themselves checked for dengue at the nearest hospital or health facility.

Secretary Duque has already ordered DOH hospitals nationwide to reestablish their Dengue Express Lane so that prompt medical attention can be given to all cases.

Misdiagnosed as flu

Dengue is characterized by fever that can go as high as 40.56 degrees Celsius (or centigrade), severe headache, and muscle and joint pains. In some cases, patients experience gastritis with some associated abdominal pain, nausea, vomiting or diarrhea.

However, the symptoms in some cases can be mild and misdiagnosed as flu or another viral infection.

“We call the rainy season dengue season because there is a rise in cases, but dengue is a disease that is present all year round,” Dr. Lyndon Lee Suy, program manager for Emerging and Reemerging Infectious Disease Prevention and Control with the DOH, also said to stress that prevention measures against dengue should be actively taken throughout the year.

“We have cases all yearlong and now—with better monitoring activities. Unfortunately this makes the public think that things are worse now than before.”

This is unfounded, Dr. Suy explains. Month on month we have less dengue cases reported this year from January to end of May. But he agrees that 5,436 reported from January to May and 32 deaths are still high figures and must be brought down by effective and conscientious prevention measures.

“We are not the only Asian country with a dengue problem,” said Dr. Suy. “The mosquitoes that transmit dengue are native to tropical and subtropical countries because the weather and temperature are conducive to their life-cycle.”

Four virus strains

Dr. Suy explains that there are four strains of dengue viruses circulating in the country. And despite some fears, none of these viruses are new. No new viruses have mutated, thank God!

“There have always been four strains of dengue viruses,” Dr. Suy told The Times. “Every mosquito population carries within it one strain of these long-recognized viruses. There is no real distinction between the effects of the viruses.”

While the bite of one mosquito infects a person with one strain of the virus, when the patient recovers, he or she will gain immunity from that strain. If, for example, one isolated community has a mosquito population with one strain of dengue then the community will be infected by that one strain. Gradually, the incidence of dengue will taper off because the surviving members of that community will all become immune.

However, in our rapidly developing world, people no longer stay in just one place. They can then be exposed to other mosquitoes carrying a strain of dengue they are not immune to. This reinfection can be more virulent because at this point the patient is only slightly immune and his immunity is compromised.

No ‘stronger’ strain

“There is no ‘stronger’ strain of dengue,” Dr. Suy explains. “How hard dengue hits a particular patient depends on the patient’s state of health before the infection.”

Owing to the four different strain of the virus, scientists have been finding it difficult to develop a vaccine for dengue fever. Which makes prevention the best defense against it.

The 4 o’clock habit

The DOH urges the public to diligently practice the 4-o’clock Habit. It is an initiative of the Philippine government that encourages neighborhood residents to daily clean their surroundings and drain water containers to prevent the spread of dengue carrier mosquitoes when clock strikes 4.

Also, as part of the 4 o’ clock habit campaign, the DOH suggests these weekly practices: clean water containers once a week, cover water containers to prevent mosquitoes from breeding, replace water in flower vases once a week, clean gutters, puncture or cut old tires used as roof support, and collect and dispose unusable tins, cans, bottles or other items that can hold water.

Negros Occidental

From January to June 12, three Negrenses died this month among the 209 dengue fever patients in Negros Occidental. These deaths prompted the Provincial Health Office (PHO) to conduct epidemiological investigation in a town 200 kilo-meters south of Bacolod.

Dr. Luisa Efren said the three deaths occurred this June in the southernmost town of Hino-baan. Three DOH experts went to the town to investigate.

Efren noted this year’s January-June 209 dengue cases represents a 49-percent increase compared to only 140 in the same period last year.

“We attribute the increase in cases to the tendency of the people to ignore the threat of dengue until the patient dies, so only several cases are reported. Dengue does not occur during rainy months only. It is endemic to the country now,” she said.

Of the dengue-affected areas in Negros Occidental, Victorias City has 54; Bago City, 28; Hinoba-an, 21; and Cadiz City, 12.

Likewise, there are nine cases each in the cities of Kabankalan, Sipalay and Talisay; eight from Sagay City; seven in Murcia; five each in Ilog, La Castellana and Manapla; four each in Pontevedra, San Carlos City, San Enrique, and Silay City; three each in Pulupandan, Don Salvador Benedicto and E. B. Magalona; two each in Isabela and Toboso; and one case each in Calatrava, Himamaylan City and Cauayan.

“No vaccine has yet been discovered against dengue so the only protection of the public is to get rid of mosquito breeding areas. A few pesos spent for antimosquito remedies can save thousands of pesos, especially lives. Patients are advised to take plenty of fluids. High fever that usually occurs on and off, headache and muscle pains are the early symptoms and those suffering from these must immediately seek medical attention,” Efren said.

Last week, Bacolod City Health Officer Dr. Edgardo Estrella reported no deaths in Bacolod since January to May 2007 although the number of dengue cases in the capital city was recorded at 209 compared to last year’s 83 during the same period.

Malaria cases

Meanwhile, in Antipolo, Rizal, residents have been alarmed by an apparent increase in malaria cases as 600 people, mostly children, from five barangays have been afflicted with the deadly and infectious mosquito-born disease.

Dr. Jun Reillo, medical officer 2 of the Antipolo Rural Health Center, said on Thursday that malaria cases continue to rise in Antipolo.

Without firm figures, informants have told The Times that the increase in June is a significant jump from 2006 figures for the same period.

The people afflicted with malaria live in barangays near the hilly areas such as Barangay San Jose, Barangay Calawis, Barangay San Luis, Barangay San Juan and Barangay San Roque.

Reillo also said that the cases are worrisome because they involve mainly children.

Malaria parasites are transmitted by female Anopheles mosquitoes. Like the mosquitoes that transmit the dengue virus, the Anopheles also like to lay their eggs in clean stagnant water.

Malaria is one of the most common infectious diseases and an enormous public-health problem. The disease is caused by protozoan parasites of the genus Plasmodium.

The Antipolo malaria victims were taken to several hospitals and rural health centers.

Doctors advised residents to cover their stored tap water and to sleep inside mosquito nets to avoid being bitten.

With Francis Early Cueto (malaria) and a report from PNA (Negros Occidental)
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Sat Jun 16, 2007 2:14 pm    Post subject: CDC: All about dengue fever Reply with quote

CDC: All about dengue fever


Dengue fever is an infectious disease carried by mosquitoes and caused by any of four related dengue viruses. This disease used to be called “break-bone” fever because it sometimes causes severe joint and muscle pain that feels like bones are breaking, hence the name. Health experts have known about dengue fever for more than 200 years.

Dengue (DF) and dengue hemorrhagic fever (DHF) are caused by one of four closely related, but antigenically distinct, virus serotypes (DEN-1, DEN-2, DEN-3 and DEN-4), of the genus Flavivirus. Infection with one of these serotypes provides immunity to only that serotype for life, so persons living in a dengue-endemic area can have more than one dengue infection during their lifetime.

DF and DHF are primarily diseases of tropical and sub tropical areas, and the four different dengue serotypes are maintained in a cycle that involves humans and the Aedes mosquito. However, aedes aegypti, a domestic, day-biting mosquito that prefers to feed on humans, is the most common Aedes species. Infections produce a spectrum of clinical illness ranging from a nonspecific viral syndrome to severe and fatal hemorrhagic disease.

Important risk factors for DHF include the strain of the infecting virus, as well as the age, and especially the prior dengue infection history of the patient.

Dengue fever is found mostly during and shortly after the rainy season in tropical and subtropical areas of Africa, Southeast Asia and China, India, the Middle East, the Caribbean, Central and South America, Australia and the South and Central Pacific.

An epidemic in Hawaii in 2001 is a reminder that many states in the United States are susceptible to dengue epidemics because they harbor the particular types of mosquitoes that transmit dengue viruses.

Worldwide, 50 to 100 million cases of dengue infection occur each year. This includes 100 to 200 cases in the United States, mostly in people who have recently traveled abroad. Many more cases likely go unreported because some health-care providers do not recognize the disease.

During the last part of the 20th century, many tropical regions of the world saw an increase in dengue cases. Epidemics also occurred more frequently and with more severity. In addition to typical dengue, dengue hemorrhagic fever (DHF) and dengue shock syndrome also have increased in many parts of the world. Globally, there are an estimated several hundred thousand cases of DHF a year.

What causes dengue fever?

Dengue fever can be caused by any one of four types of dengue virus: DEN-1, DEN-2, DEN-3 and DEN-4. You can be infected by at least two if not all four types at different times during your lifetime, but only once by the same type.

How is dengue fever transmitted?

You can get dengue virus infections from the bite of an infected Aedes mosquito. Mosquitoes become infected when they bite infected humans, and later transmit infection to other people they bite. Two main species of mosquito, aedes aegypti and aedes albopictus, have been responsible for all cases of dengue transmitted in the United States.

Dengue is not contagious from person to person.

What are the symptoms of dengue infection?

Symptoms of typical uncomplicated (classic) dengue usually start with fever within four to seven days after you have been bitten by an infected mosquito and include the following:

High fever, up to 40.56ºC or 105ºF

Severe headache

Retro-orbital (behind the eye) pain

Severe joint and muscle pain

Nausea and vomiting

Rash

The rash may appear over most of your body 3 to 4 days after the fever begins, and then subsides after 1 to 2 days. You may get a second rash a few days later.

Symptoms of dengue hemorrhagic fever include all of the symptoms of classic dengue plus:

Marked damage to blood and lymph vessels

Bleeding from the nose, gums, or under the skin, causing purplish bruises

This form of dengue disease can cause death.

Symptoms of dengue shock syndrome—the most severe form of dengue disease—include all of the symptoms of classic dengue and dengue hemorrhagic fever, plus fluids leaking outside of blood vessels, massive bleedingn, shock (very low blood pressure).

This form of the disease usually occurs in children (sometimes adults) experiencing their second dengue infection. It is sometimes fatal, especially in children and young adults.

How do doctors and other health-care providers diagnose dengue fever?

Your health-care provider can diagnose dengue fever by doing two blood tests, 2 to 3 weeks apart. The tests can show whether a sample of your blood contains antibodies to the virus. In epidemics, a health-care provider often can diagnose dengue by typical signs and symptoms.

What is the treatment for dengue?

There is no specific treatment for classic dengue fever, and most people recover within 2 weeks. To help with recovery, health care experts recommend:

Getting plenty of bed rest
Drinking lots of fluids
Taking medicine to reduce fever

The Center for Diseases Control (CDC) advises people with dengue fever not to take aspirin. Acetaminophen or other over-the-counter pain-reducing medicines are safe for most people.

For severe dengue symptoms, including shock and coma, early and aggressive emergency treatment with fluid and electrolyte replacement can be lifesaving.

Personal prevention

The best way to prevent dengue virus infection is to take special precautions to avoid being bitten by mosquitoes. Several dengue vaccines are being developed, but none is likely to be licensed by the Food and Drug Administration in the next few years.

When outdoors in an area where dengue fever has been found use a mosquito repellant containing DEET, picaridin, or oil of lemon eucalyptus.

Dress in protective clothing-long-sleeved shirts, long pants, socks and shoes.

Because Aedes mosquitoes usually bite during the day, be sure to use precautions especially during early morning hours before daybreak and in the late afternoon before dark.

Other precautions include:

Keeping unscreened windows and doors closed

Keeping window and door screens repaired

Getting rid of areas where mosquitoes breed, such as standing water in flowerpots, containers, birdbaths, discarded tires, etc.

Dengue fever complications

Most people who develop dengue fever recover completely within 2 weeks. Some, especially adults, may be tired and/or depressed for several weeks to months after being infected with the virus.

The more clinically severe dengue hemorrhagic fever and dengue shock syndromes can result in vascular (blood vessel) and liver damage, and can be life-threatening.

Research

Scientists supported by the National Institute of Allergy and Infectious Diseases (NIAID) are trying various approaches to develop vaccines against dengue. Researchers in NIAID laboratories in Bethesda, Maryland, are using weakened and harmless versions of dengue viruses as potential vaccine candidates against dengue and related viruses. Other NIAID-funded investigators are trying to develop dengue virus vaccines using recombinant proteins (with or without adjuvant), viral vectors, and DNA.

Several projects are currently ongoing to identify the host and viral factors that determine the virulence and transmissibility of different dengue virus strains.

Other researchers supported by NIAID are investigating ways to treat infected individuals and to prevent dengue viruses from reproducing inside mosquitoes.

Although dengue virus has emerged as a growing global threat, scientists know little about how the virus infects cells and causes disease. New research is beginning to shed light on how the virus interacts with humans; for example, how dengue virus damages cells and how the human immune system responds to dengue virus invasion.

History of dengue

The first reported epidemics of DF occurred in 1779-1780 in Asia, Africa and North America. The near simultaneous occurrence of outbreaks on three continents indicates that these viruses and their mosquito vector have had a worldwide distribution in the tropics for more than 200 years. During most of this time, DF was considered a mild, nonfatal disease of visitors to the tropics. Generally, there were long intervals (10-40 years) between major epidemics, mainly because the introduction of a new serotype in a susceptible population occurred only if viruses and their mosquito vector could survive the slow transport between population centers by sailing vessels.

A pandemic of dengue began in Southeast Asia after World War II and has spread around the globe since then.
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Sat Jun 16, 2007 2:15 pm    Post subject: Community and personal steps Reply with quote

Community and personal steps to prevent and fight dengue

By Katrice Jalbuena , Reporter

From a community viewpoint, the best defense against dengue fever and dengue hemorrhagic fever—and the best way to stop it from spreading—is to do everything to help keep the mosquito population down.

The dengue and DH viruses are spread by the aedes aegypti, a day-biting mosquito species, characterized by the white dots or lines on the legs and body.

“Remember, aedes aegypti thrives in clean water, not in dirty water. So in areas where there is an accumulation of clean water, these mosquitoes may not be far away,” said Health Secretary Francisco Duque 3rd.

Duque noted that to keep these mosquitoes away, the public must regularly clean their surroundings and get rid of items like used tires and empty cans where clean water could build up.

“The campaign against dengue is largely dependent on community cooperation. It is important for those in the community to clean their surroundings regularly,” he said. “This is a campaign that must be fought all year round, but there is also a need for increased vigilance during the rainy season.”

During the rainy season, there is an increase in the mosquito population simply because there is an increase in their breeding areas.

The most effective way is to conduct regular “search and destroy” missions against possible breeding areas of dengue mosquitoes.

Chemical fogging is a costly endeavor and a time-limited measure. The Department of Health recommends the use of chemical fogging only in the case of an outbreak of mosquito-borne diseases, like dengue and malaria.

“Fogging activities bring about a false sense of complacency,” said Dr. Lyndon Lee Suy of the DOH Emerging and Reemerging Infectious Disease Control and Prevention program. “Their effects are only temporary. They do not prevent another outbreak as the mosquito population can survive as long as there are still breeding grounds.”

Fogging might even contribute to the spread of dengue as it will force mosquitoes—which can fly and easily move from one place to another—to relocate into an area where they were previously not a problem and might end up being a more hospitable breeding ground for them.

If they find conducive breeding grounds, the population will once again grow, this time covering a wider area.

If fogging must be done, the health department recommends that it still be combined with search and destroy methods.

The following tips are recommended to prevent the spread of dengue by controlling the mosquito population.

Cover water drums and water pails at all times to prevent mosquitoes from breeding.

Replace water in flower vases once a week.

Clean all water containers once a week. Scrub the sides well to remove eggs of mosquitoes sticking to the sides.

Clean gutters of leaves and debris so that rain water will not collect and become breeding places of mosquitoes.

Old tires used as roof support should be punctured or cut to avoid accumulation of water.

Collect and dispose all unusable tin cans, jars, bottles and other items that can collect and hold water.

For personal safety against mosquitoes, the Center for Diseases Control in the United States gives this advice:

“|The best way to prevent dengue virus infection is to take special precautions to avoid being bitten by mosquitoes. Several dengue vaccines are being developed, but none is likely to be licensed by the Food and Drug Administration in the next few years.

“When outdoors in an area where dengue fever has been found use a mosquito repellant containing DEET, picaridin, or oil of lemon eucalyptus. Dress in protective clothing—long-sleeved shirts, long pants, socks and shoes.

“Because Aedes mosquitoes usually bite during the day, be sure to use precautions especially during early morning hours before daybreak and in the late afternoon before dark.”

Other precautions recommended by DCD include

Keeping unscreened windows and doors closed, keeping window and door screens repaired.
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Tue Oct 16, 2007 1:31 pm    Post subject: Substantial costs and underreporting of dengue fever, concer Reply with quote

American Society of Tropical Medicine and Hygiene
16 October 2007

Substantial costs and underreporting of dengue fever, concerns about blood supply face US

Research to be presented at the 56th Annual American Society of Tropical Medicine and Hygiene Meeting in Philadelphia
Dengue fever, known as “breakbone fever” because of the excruciating back and joint pain that accompanies this infectious disease, is a growing public health threat for people living in tropical countries, as well as travelers to destinations such as Thailand, Brazil and Puerto Rico, according to research being presented at the annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH), Nov. 4-7.

Protocol Needed to Screen Blood Donors

Dengue, which is believed to infect millions of people annually in developing countries, and also causes some infections in Texas along the border of Mexico, is usually transmitted by mosquitoes. A recent study examined the prevalence of dengue virus among blood donors in Puerto Rico and found that one in every 1,300 donors tested positive during the 2005 epidemic, which means that this sometimes fatal disease might be transferred to others through the blood supply.

“The frequency of finding dengue virus in blood donors during outbreaks is comparable to what we see with West Nile virus,” said Susan Stramer, executive scientific officer, American Red Cross. “However, we still need to better understand transfusion-associated transmission of dengue and the dynamics of the virus in donors.” Still, the American Red Cross and public health officials plan to start dengue blood donor screening using a research protocol in Puerto Rico in 2008.

Underreporting Remains Public Health Concern

Researchers believe that dengue is grossly underreported in many countries. For example, in 2004, 557,000 cases and 1,800 deaths were reported globally to WHO, but the projected dengue burden was more than 8 million cases and nearly 20,000 deaths. In addition to underreporting, the lack of a rapid and accurate diagnostic test, potential misdiagnoses of milder forms of dengue as influenza, as well as limited data further challenge efforts to measure the global burden of this threatening disease. And, with no drugs available to treat dengue, patients’ prognosis relies on good medical management, including rest, fluids and pain relief.

Direct and Indirect Costs of Dengue

In the first comprehensive, multi-country analysis of dengue by all stakeholders (households, employers and public health systems), the new study reveals a substantial epidemiological, social and economic burden associated with the disease. “On average, a hospitalized case of dengue costs three times that of an ambulatory case,” said Jose Suaya, scientist at Brandeis University and co-investigator of the study, which was conducted in eight countries across South East Asia and South America from 2005-2006.

“An episode of dengue has a tremendous impact on the government, households and employers,” said Donald Shepard, professor at Brandeis University and co-investigator of the study. “More attention is needed to understand global patterns of dengue and related costs to develop sound policy and appropriately allocate resources for its prevention and treatment. We believe this data is an important first step.”

Researchers assessed direct medical costs, non-medical costs and indirect costs (e.g., days lost by patients and caretakers from school, work) and found that even though countries have major public health systems that pay for care, there was a heavy toll on households due to out-of-pocket expenses. For ambulatory patients, families assume most of the burden, and even when someone is hospitalized, they assume about 25% of the related costs.
Back to top
View user's profile Send private message Visit poster's website
adedios
SuperPoster


Joined: 06 Jul 2005
Posts: 5060
Location: Angel C. de Dios

PostPosted: Wed Jan 09, 2008 11:50 am    Post subject: NIAID experts see dengue as potential threat to US public he Reply with quote

NIH/National Institute of Allergy and Infectious Diseases
8 January 2008

NIAID experts see dengue as potential threat to US public health

A disease most Americans have never heard of could soon become more prevalent if dengue, a flu-like illness that can turn deadly, continues to expand into temperate climates and increase in severity, according to a new commentary by Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, and David M. Morens, M.D., Fauci’s senior scientific advisor. Their commentary appears in the January 9 and 16 double issue of the Journal of the American Medical Association.

Previously confined to tropical and subtropical climates, the mosquito-borne illness is becoming a much more serious problem along the U.S.-Mexico border and in the commonwealth of Puerto Rico. Dengue occurs sporadically and has had a relatively small impact on the United States thus far, so the amount of dengue-related illness in this country is presently minimal. However, the disease tends to occur in explosive epidemics. Moreover, the NIAID scientists note, efforts to control the populations of mosquitoes that transmit dengue have fallen short of their goal.

These trends stimulated Drs. Fauci and Morens to call for more research to understand and combat dengue. “Widespread appearance of dengue in the continental United States is a real possibility,” the NIAID scientists write in their commentary. “Worldwide, dengue is among the most important reemerging infectious diseases with an estimated 50 to 100 million annual cases…[and] 22,000 deaths.” Public health officials need to take the threat seriously, the scientists assert, because no specific treatments or vaccines for dengue are available. To fight the disease, they state, “The formidable challenges of understanding dengue pathogenesis and of developing effective therapies and vaccines must be met.”

Dengue (pronounced “DENG-ee”) is caused by any of four related viruses transmitted to humans by the mosquitoes Aedes albopictus (nicknamed “Asian tiger mosquito”) and Aedes aegypti. First seen in the United States in 1985, Ae. albopictus has been found in 36 states, while Ae. aegypti has been found in several southern states. Experience elsewhere in the world shows that where these mosquitoes go, the disease usually follows.

In their commentary, Drs. Fauci and Morens provide a historical and clinical overview of dengue; discuss the controversy about the origins and development of the most severe forms of the disease; describe the implications of dengue pathogenesis for safe vaccination strategies; and note the challenges to dengue treatment, control and prevention. The scientists highlight the hypothesis that naturally and maternally acquired dengue antibody may precipitate severe disease on subsequent infection. This hypothesis has implications for dengue vaccine development, the authors write, because a vaccine could potentially stimulate the immune system to cause more severe disease on subsequent natural infection.

Most people infected with a dengue virus have no symptoms or a mild fever. Those who do get sick sometimes experience minor bleeding, such as from the nose or gums, and frequently develop a high fever, severe headache, pain behind the eyes and in joints and muscles, and a rash. Sometimes the disease leads to leakage of blood plasma out of the circulatory system and into tissues, causing blood pressure to drop. This condition often can be reversed by giving patients fluids and electrolytes. With proper treatment, case fatality rates for severe dengue can be less than 1 percent. If left untreated, however, the person may become unresponsive, slip into a coma and possibly die. Early diagnosis and treatment of dengue are critical to preventing shock and death. The severe forms of dengue disease have been defined by the World Health Organization as dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS).

Recognizing the threat to public health posed by dengue, NIAID allocated $33.2 million in fiscal year 2007 for nearly 60 dengue research projects, including basic research on dengue, DHF and DSS; projects to develop vaccines, diagnostics and therapeutics for the disease; and clinical trials of vaccines.

The priorities of NIAID’s dengue research program include the following:


Develop animal models to study the basic mechanisms of infection and perform preliminary tests of vaccines and therapeutics
Design and evaluate vaccines and therapeutics
Understand how dengue viruses can elicit antibodies—normally a form of protection against disease—that may help the viruses infect host cells and exacerbate the disease
Learn what causes capillaries to leak plasma in DHF and DSS
Understand the genetic factors in both people and dengue viruses that influence the severity of the disease
Identify biological markers that might predict whether an individual is protected from dengue viruses and whether a person with dengue fever will likely develop DHF or DSS

By vigorously pursuing these research priorities, NIAID hopes to advance the development of medical tools to fight this important reemerging infectious disease.


###
NIAID is a component of the National Institutes of Health. NIAID supports basic and applied research to prevent, diagnose and treat infectious diseases such as HIV/AIDS and other sexually transmitted infections, influenza, tuberculosis, malaria and illness from potential agents of bioterrorism. NIAID also supports research on basic immunology, transplantation and immune-related disorders, including autoimmune diseases, asthma and allergies.
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic   printer-friendly view    USAP PAETE Forum Index -> Science Lessons Forum All times are GMT - 5 Hours
Page 1 of 1

 
Jump to:  
You can post new topics in this forum
You can reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group