Dengue Rapid Test in 15 minutes
It is almost two years since the announcement was made, but it is still worthy of note that Inverness Medical Inc. has put an Early Rapid Test for Dengue Fever on the market to help physicians diagnose Dengue from the very first day it shows up in the bloodstream. As a matter of fact, the three-part test purports to facilitate a specific diagnosis of Dengue in 15 minutes thereby shortening the response time for patient therapy and monitoring to begin.
The Panbio Dengue Early Rapid Test was developed, not as a standalone diagnostic tool by any means. Rather, it acts as a cross-reference for other existing serology tests.
The Panbios test gives physicians the added advantage of reducing the risk of severe complications of Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS) in patients for whom this is a second or subsequent Dengue infection. Now, that can be fatal if not identified and treated early.
Source: biospace.com
Dengue Vaccine Advances in Cuba
Patricia Grogg interviews MARÍA GUADALUPE GUZMÁN, director of a team of Cuban researchers working on a vaccine against dengue * – Tierramérica
HAVANA TIMES, Nov 15 (IPS) – “We don’t like to talk about our specific goals,” says Cuban virologist María Guadalupe Guzman, as a subtle way to avoid going into too much detail about the research she is heading up to develop a dengue vaccine.
There are a number of research projects underway around the world aimed at a vaccine against dengue, a mosquito-borne infection that causes a severe flu-like illness, and sometimes a potentially lethal complication called dengue hemorrhagic fever. Until a vaccine is discovered, however, the most important task is to control the mosquito that spreads it, Aedes aegypti, stressed Guzman.
Although historically considered a tropical disease, dengue knows no borders today, she also emphasized. The World Health Organization (WHO) reports that the global incidence of dengue has “grown dramatically” in recent decades, and about two fifths of the world’s population are now at risk.
Guzman works for the Pedro Kourí Institute (IPK) directing a team of 14 scientists, most of them women, in a joint project with the Centre for Genetic Engineering and Biotechnology (CIGB), whose research team is headed up by Gerardo Guillén.
The major dengue epidemic that hit Cuba in 1981 defined the career path of Guzman, head of the IPK Department of Virology and director of the PAHO (Pan American Health Organization)/WHO Collaborating Centre for the Study of Dengue and its Vector.
The Cuban government maintains that the disease was introduced into the country by United States agents. Studies of the first cases to appear have made it possible to confirm that “this is not the normal pattern of a mosquito-borne disease,” Guzman told Tierramérica in this interview.
Q: Have you been able to demonstrate that the 1981 epidemic was intentionally introduced in Cuba?
A: We have confirmed that the virus that was circulating here at that time was similar to the so-called old strains from Southeast Asia. It was from the years 1968 and 1944, and wasn’t circulating in Asia at the time.
In addition, a study conducted by the Ministry of Public Health revealed that the first cases of dengue appeared in three different parts of the country, in the same week, and in people who hadn’t traveled anywhere. This is not the normal pattern of a mosquito-borne disease.
Q: What contributions has Cuba made to the studies on dengue being carried out around the world?
A: I would say they began with the 1981 epidemic itself. This was the first hemorrhagic dengue epidemic in the Americas, and we had to learn as we went along, because nobody had faced this problem before. It required the urgent preparation of the necessary hospital conditions and the establishment of guidelines to control the disease.
In four months, Cuba managed to bring an end to an epidemic of over 300,000 cases, including more than 10,000 severe cases and 158 fatal ones. It demonstrated the decisive role played by political will and the participation of the community and all of the sectors involved in one way or another in the problem.
Cuba contributed a great deal through this experience, from the characterization of the epidemic, to the clinical study of individual cases, especially in adults with hemorrhagic dengue – which until then had only been seen in Southeast Asia and in children – to the methods for bringing this epidemic under control in four months.
Q: And in the field of virology?
A: At the time of the epidemic we were able to determine that in order for hemorrhagic dengue to occur, there must be secondary infection. We subsequently demonstrated that 20 years after contracting dengue, you are at greater risk of developing the hemorrhagic variety if you contract the disease again. You have a sword of Damocles hanging over your head for the rest of your life.
In Cuba it was also demonstrated that as an epidemic advanced and the number of cases decreased, the number of serious cases began to rise. This has happened on three occasions. The virus somehow changes over the time in which the epidemic takes place. Changes occur in the structure of the virus genome as well. This was a new observation made by Cuba.
In more recent studies we have been working on research on the genes of individuals, because your particular genetic “stock” could predispose you to certain diseases. Our group has published various studies on genes that could possibly be associated with greater susceptibility to dengue or hemorrhagic dengue.
This year a very interesting study from Vietnam was published, on the association between certain genes and hemorrhagic dengue. We also conducted a similar study, with fewer cases, published this year. The same observation was made by two different groups.
Q: To what extent does climate change influence the transmission of dengue?
A: We know that the climate can have an influence, although there are few studies on the subject. We believe it is a factor, but not necessarily the only one. WHO has reported that when the temperature is one or two degrees higher, the mosquito may be able to transmit the virus in a shorter time. This is a major line of research.
Q: There are four dengue viruses and four strains or serotypes. Is any one of them linked more than the others to hemorrhagic dengue?
A: Hemorrhagic dengue is a clinical classification; all of the viruses can produce it. However, within a given virus there may be different strains, and, in general, those which are isolated in Southeast Asia or other Asian countries have a greater potential to produce hemorrhagic dengue.
These viruses continue to change and transform as they spread from one person to another. As time passes, when we refer to the American-Asian genotype, these are no longer the same strains that arrived from Asia.
Q: Do these mutations of the virus complicate the search for a vaccine?
A: Yes. But a lot of progress has been made in this area. There are currently six or seven vaccine candidates worldwide. The most advanced is the one being developed by Sanofi Pasteur, and according to their reports, it could be ready in seven years. It’s a live chimerical virus vaccine (obtained through recombinant DNA technology). There are other similar candidates that are also quite advanced.
Our project is a joint effort between the IPK and CIGB. It isn’t a live vaccine, but rather a recombinant subunit vaccine, which has had satisfactory results in preclinical studies with monkeys. We still haven’t moved on to studies with humans, but we also don’t like to talk about our specific goals in that regard.
*The writer is an IPS correspondent. This story was originally published by Latin American newspapers that are part of the Tierramérica network. Tierramérica is a specialized news service produced by IPS with the backing of the United Nations Development Program, United Nations Environment Program and the World Bank.
Fort Collins company presents results of its testing for dengue fever vaccine|written by Pat Ferrier
Clinical trials of a vaccine developed by a Fort Collins biopharmaceutical company are showing promise in fighting dengue fever.
Inviragen, Inc., presented the results of its Phase 1 clinical trials Wednesday [December 07, 2011] at the American Society of Tropical Medicine and Hygiene meeting in Philadelphia, Penn.
According to the report, two vaccines, given 90 days apart, generated “neutralizing antibody responses to all four dengue strains,” Dr. Jorge Osorio, Inviragen’s chief scientific officer said in a press statement.
Other vaccines in development require three doses, according to CEO Dan Stinchcomb, creating more convenience for the consumer, better compliance and a competitive advantage for Inviragen.
“It’s easier to get people dosed with two,” Stinchcomb said in a telephone interview from Philadelphia.
“If you’re thinking of traveling to endemic countries, it’s difficult to plan a year in advance and receive three doses rather than two a few months before you travel.”
The two-dose product profile “will mean it will be really competitive when it gets to market and can provide Inviragen with an edge in the marketplace.”
Inviragen officials estimate the potential market for a new vaccine could be in the “billions of dollars” range worldwide.
The vaccine, tested in Rionegro, Colombia, a high-altitude area with none of the mosquitoes that carry and transmit dengue fever, will now go through Phase 2 clinical studies in areas where dengue is prevalent including Puerto Rico, Colombia, Singapore and Thailand.
Despite the successful Phase I clinical trials, the DENVax vaccine is still “several years ago, but we’re distinctly closer,” Stinchcomb said.
If Phase 2 studies are successful, Inviragen will begin large-scale Phase 3 studies, likely in 2013, “to show it protects against the disease,” Stinchcomb said…
Inviragen Initiates a Phase 2 Clinical Study of DENVax, a Recombinant, Tetravalent Dengue Vaccine
- Positive Phase 1 Safety and Immunogenicity Results…Presented at 2011 ASTMH Meeting -
FORT COLLINS, Colo., Nov 28, 2011 (BUSINESS WIRE) — Inviragen, Inc. today announced the initiation of a Phase 2, randomized, double-blind, placebo-controlled study of DENVax, the Company’s investigational dengue vaccine. The Phase 2 trial will test the safety and immunogenicity of DENVax in multiple age groups in dengue endemic countries. The initiation of this Phase 2 study follows the successful conclusion of a Phase 1 study of DENVax that was conducted in Colombia in collaboration with PECET, the Program for the Study and Control of Tropical Diseases at Universidad de Antioquia. Data from this Phase 1 study demonstrate that the vaccine is safe and well-tolerated and immunogenic in dengue-naive adults; the results [were] presented at the annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH) on December 7, 2011 in Philadelphia, PA.
“Worldwide, dengue viruses infect young children as well as adults, causing devastating disease and tens of thousands of deaths every year,” said Dr. Dan Stinchcomb, CEO of Inviragen. “This Phase 2 study will further assess the safety and immunogenicity of DENVax in adults as well as children in dengue endemic countries.”
The Phase 2 clinical trial will evaluate safety and immunogenicity of DENVax, administered in two doses three months apart. In the first stage of the trial, individuals will be enrolled in four age groups: adults (aged 21 and older), adolescents (aged 11 to 20 years), pre-teens (aged 6 to 10 years) and children (aged 18 months to 5 years). An independent monitoring board will assess safety of the vaccine in subjects from each group before advancing to the next younger cohort. Following complete safety measurements in all four cohorts, the study will enter its second stage, enrolling hundreds of additional children aged 18 months to 11 years to further test the safety and immunogenicity of the two-dose DENVax vaccine.
Inviragen intends to enroll individuals in Puerto Rico, Colombia, Singapore and Thailand. “We are collaborating with leading clinical researchers in three continents to test the safety and immune responses to DENVax,” commented Dr. Gilad Gordon, Inviragen’s chief medical officer. “The data from this clinical study will provide the foundation for future large-scale Phase 3 efficacy studies to determine whether DENVax protects individuals from dengue fever in endemic countries.”
International Experts OutlinePublicHealth Initiatives For Future Dengue Vaccine Introduction And Control Of Dengue Fever
SAN JUAN, Puerto Rico, Nov. 8, 2011 /NEWS.GNOM.ES/ — Dengue v2V, a group of international experts in dengue, public health and vaccinology held its meeting in Puerto Rico on 5–6 November 2011 to continue to outline steps for the introduction of a dengue vaccine once licensed. Dengue is a threat to almost half of the world’s population, and a public health priority in Latin America and Asia where epidemics are common.
“Puerto Rico was a relevant venue for this meeting given its location and experience with both endemic and epidemic dengue activity,” said Dr Harold Margolis, Chief of the Dengue Branch at the Centers for Disease Control, Puerto Rico and co-Chair of the meeting. “In addition to mosquito control measures, a dengue vaccine is seen as the best way to effectively control dengue.”
“The well coordinated introduction of a dengue vaccine will be crucial to reducing the burden of disease, but vaccination programs are complex to implement and dengue itself presents unique challenges. It is critical that we anticipate the challenges ahead of us and start preparing now,” said Associate Professor Joseph Torresi, Austin Health and University of Melbourne, Australia, and co-Chair of the meeting.
Attendees at the Dengue v2V International Meeting included dengue experts, vaccinology experts, and public health officials from Puerto Rico, Australia, Brazil, Colombia, Costa Rica, Ecuador, France, the French Caribbean, Korea, Mexico, the Philippines, Singapore, Thailand, the United Kingdom and the United States, who drew on their experiences with dengue and other vaccination programs to propose strategies for dengue vaccine introduction and evaluation of its effectiveness. Encouragingly, the most advanced vaccine candidate is in the final stages of clinical development.
The meeting in Puerto Rico is part of the ongoing efforts of Dengue v2V to ensure that a dengue vaccine, once licensed, is readily available to those who need it most.
The objectives of Dengue v2V include:
- Documenting the human and economic burden of dengue
- Providing guidance regarding vaccine adoption strategies based on clinical, epidemiological and other technical data
- Making recommendations regarding the introduction of a dengue vaccine for routine and catch-up immunization
LSU researcher aims to predict emerging viruses
Much research over the decades has been concentrated on the vexing issue of a lack of an effective Dengue vaccine. But how about being able to better predict how the Dengue virus is transmitted, how the disease is spread and its impact on public health measures designed to control it?
Well, these lines of research are to be advanced with the injection of a US$3 million grant from the National Institutes of Health (NIH) to researchers of the Louisiana State University (LSU), Tulane University and the University of New Mexico led by Associate Professor of the LSU Christopher Mores.
This money, to be disbursed over the next five years, paves the way for Dr. Mores and his consortium to join an NIH study that uses modelling techniques to understand the spread of contagion and measure how that impacts public health measures, namely community-based and international intervention strategies.
Dr. Mores’ particular goal in the context of the wider study will be to mature a set of tools that Vector Control practitioners can use to forecast the transmission of viral diseases, especially Dengue. To do so would be to learn more about the way infectious diseases spread both at the level of vector and human populations.
Given the financial burden Dengue has had on health services in tropical and sub-tropical regions around the world, we will take all the help we can get.
Source: Journal of the American Veterinary Medical Association (JAVMA)
This US$3 million dollar grant that the NIH gave to Dr. Mores’ consortium is, however, a drop in the bucket compared to the US$45 million the agency handed to Silver Spring biotech firm, United Therapeutics.
Working through their respective subsidiaries, United Therapeutics and National Institutes of Health signed a contract, pro-rated over five years, requiring Unither Virology to develop a treatment – not a vaccine – for Dengue.
In turn, UV has entered into a research agreement with Oxford Glycobiology Institute to undertake the studies as prescribed.
Source: Gazette.Net
La Jolla Institute scientists prove hypothesis on the mystery of dengue virus infection
SAN DIEGO – A leading immunology research institute has validated the long-held and controversial hypothesis that antibodies – usually the “good guys” in the body’s fight against viruses – instead contribute to severe dengue virus-induced disease, the La Jolla Institute for Allergy & Immunology announced [July 07, 2100]. The finding has major implications for the development of a first-ever vaccine against dengue virus, a growing public health threat which annually infects 50 to 100 million people worldwide, causing a half million cases of the severest form.
“Our lab has proven the decades old hypothesis that subneutralizing levels of dengue virus antibodies exacerbate the disease,” said La Jolla Institute scientist Sujan Shresta, Ph.D, noting this occurs in people with secondary dengue virus infections who have antibodies to the virus due to a previous infection. [...]
The dengue virus antibody phenomenon, termed antibody-dependent enhancement of infection (ADE), was first hypothesized in the 1970s by Scott Halstead, M.D., a renowned scientist and one of the world’s top experts on dengue virus infection. Dr. Halstead said he got his first inkling of the phenomenon while doing extensive clinical studies of dengue virus patients in Thailand in the 1960s. “We were able to detect that the severe patients all had a secondary antibody response, meaning that they had all been infected before,” he said. “That was the first evidence we had that a person had to have a previous dengue infection to get the severe disease.” Further epidemiological observations, including cases in which severe dengue virus occurred in infants born to previously infected mothers, along with lab cell studies, prompted Dr. Halstead to put forth the ADE hypothesis. Dr. Shresta’s work, conducted in mouse models, provides the first in vivo proof of ADE’s occurrence. [...]
Dr. Shresta’s findings were published online today in Cell Host & Microbe in her paper entitled, “Enhanced Infection of Liver Sinusoidal Endothelial Cells in a Mouse Model of Antibody-Induced Severe Dengue Disease.”
Dr. Shresta said the fact that dengue viruses exist as four different serotypes that circulate simultaneously underlies the development of the subneutralizing antibodies. Infection with one of these serotypes provides lifelong immunity to the infecting serotype only. In subsequent dengue infections, where a different serotype of the virus is involved, the antibodies do not recognize enough of the virus to neutralize it. “This starts a cascade of unusual molecular events – the ADE process — which leads to the antibodies contributing to, rather than fighting, the dengue infection,” she said. [...]
SANOFI AVENTIS RECRUITING MORE THAN 4000 INDIVIDUALS FOR A PHASE II DENGUE CLINICAL TRIAL June 29th, 2010 by Kerentech
As the virus spreads in the tropics, experts are continuing to push toward an ultimate solution for the mosquito-borne illnesses: an effective and affordable vaccine. There are no drugs for the disease.
Jean Lang, a doctor who heads the vaccine division of the deep-pocketed pharmaceuticals company Sanofi Pasteur Inc., last month presented the world’s most advanced effort to vaccinate against dengue to a room full of industry insiders in Chicago. The market for a vaccine is huge, with experts pegging sales at between $700 million and $1 billion per year. In comparison, the company’s top-selling drug right now, an insulin injection called Lantus, nets $3.7 billion per year.
“If everything goes well, we will have phase 3 trials on an industrial scale by the end of the year,” Lang remarked. He spoke of nearly 100 million people worldwide getting the disease and 25,000 people dying in tropical countries per year.
Henry Daniell of University of Central Florida works developing “green vaccines” | provided by University of Central Florida
A University of Central Florida biomedical researcher has developed what promises to be the first low-cost dual vaccine against malaria and cholera.
There is no FDA approved vaccine to prevent malaria, a mosquito-borne illness that kills more than 1 million people annually. Only one vaccine exists to fight cholera, a diarrheal illness that is common in developing countries and can be fatal. The lone vaccine is too expensive to prevent outbreaks in developing countries after floods, and children lose immunity within three years of getting the current vaccine.
“I’m very encouraged because our technique works well and provides an affordable way to get vaccines to people who need them most and can least afford them,” said lead scientist Henry Daniell.
Daniell’s team genetically engineered tobacco and lettuce plants to produce the vaccine. Researchers gave mice freeze-dried plant cells (orally or by injection) containing the vaccine. They then challenged the mice with either the cholera toxin or malarial parasite. The malaria parasite studies were completed in fellow UCF professor Debopam Chakrabarti’s lab.
Untreated rodents contracted diseases quickly, but the mice who received the plant-grown vaccines showed long-lasting immunity for more than 300 days (equivalent to 50 human years).
Results from the National Institutes of Health-funded research are published in (January) month’s Plant Biotechnology, the top-ranked journal in the field…
Gene map of anti-malaria plant could boost supply | by Doreen Walton, Science reporter, BBC News
New Malaria Vaccine Initiative Aims to Stunt Parasite within Mosquitoes | Joe DeCapua, VOANews.com (English)
A new vaccine initiative has been launched to try to prevent the malaria parasite from developing inside mosquitoes.
Malaria kills about one million people every year, most of them children under age five. Researchers say if successful so-called transmission-blocking vaccines could significantly limit the spread of infection. Once a mosquito bites a vaccinated person, it picks up a substance that interferes with parasite growth.
The Malaria Vaccine Initiative, Johns Hopkins Bloomberg School of Public Health and the Sabin Vaccine Institute are collaborating in the effort…
Malignant malaria found in apes | by Doreen Walton, Science reporter, BBC News
The parasite which causes malignant malaria in humans has been identified in gorillas for the first time.
Researchers analysed faeces from wild gorillas in Cameroon and blood samples from a captive animal from Gabon.
The study says increasing contact between humans and primates due to logging and deforestation raises the risk of transmission of new pathogens.
The research findings are published in Proceedings of the National Academy of Sciences journal…
An Indian origin researcher in Malaysia has confirmed the potentially deadly nature of an emerging new form of malaria, mainly found in monkeys, by identifying key laboratory and clinical features of the disease.
Researchers at the University Malaysia Sarawak, led by Professors Balbir Singh and Janet Cox-Singh, showed that Plasmodium knowlesi, a malaria parasite previously thought to mainly infect only monkeys – in particular long-tailed and pig-tailed macaques found in the rainforests of Southeast Asia – was widespread amongst humans in Malaysia.
And after reports in neighbouring Southeast Asian countries, researchers have recognised P. knowlesi as the fifth cause of malaria in humans.
Now, the researchers have for the first time given a detailed prospective study of the clinical and laboratory features of human P. knowlesi infections…
U.S. Scientists Find Ideal Target for Malaria Therapy | by Web Editor: Zhang Xu, Xinhua
Scientists at Washington University School of Medicine in St. Louis have identified a protein made by the malaria parasite that is essential to its ability to take over human red blood cells, the university said Wednesday in a statement.
Malaria, which is spread by mosquito bites, kills between one million and three million people annually in developing countries. Death results from damage to red blood cells and clogging of the capillaries that feed the brain and other organs.
“The malaria parasite seizes control of and remodels the red blood cell by secreting hundreds of proteins once it’s inside,” says Dan Goldberg, professor of medicine and of molecular microbiology and a Howard Hughes Medical Institute Investigator. ” But without this protein, plasmepsin V, those other proteins can’t get out of the parasite into the blood cell, and the infectious process stops.”
The closest equivalent to plasmepsin V in humans is a protein called beta secretase, but it’s only distantly related. The significant differences between the malarial protein and its closest human relative may mean scientists will be able use drugs to disable plasmepsin V with little worry of adverse side effects on human biology, according to Goldberg.
The results are reported in Nature this week. In a second paper in the same issue of Nature, a group in Australia reported similar conclusions…
Vaccine Possible: Hypothesis on the Mystery of Dengue Virus Infection Confirmed | by ScienceDaily
A leading immunology research institute has validated the long-held and controversial hypothesis that antibodies — usually the “good guys” in the body’s fight against viruses — instead contribute to severe dengue virus-induced disease, the La Jolla Institute for Allergy & Immunology has announced. The finding has major implications for the development of a first-ever vaccine against dengue virus, a growing public health threat which annually infects 50 to 100 million people worldwide, causing a half million cases of the severest form…
Pinoy prof in US develops anti-malaria vaccine | by gmanews.tv
A Filipino professor in the US has developed a “robust” vaccine against malaria.
Dr. Rhoel Dinglasan, a professor at the Johns Hopkins Bloomberg School of Public Health, has developed a new kind of transmission-blocking vaccine (TBV), which works by preventing mosquitoes from spreading the disease.
In a newscast by GMA’s 24 Oras, Dinglasan, a faculty of the school’s molecular microbiology and immunology department, explained that the vaccine prevents the development of the malaria parasite in mosquitoes, thereby also preventing its transmission to humans…
UPR seeking volunteers for dengue vaccine study | by Puerto Rico Daily Sun
The University of Puerto Rico Medical Sciences School…(recruited) volunteers to participate in a study of a vaccine that could help reduce dengue infection by 50 percent.
Medical Sciences…(sought) 150 patients before the end of February. Since the highest dengue statistics reported since 1990 have occurred among children and adolescents from 9 to 14 years old, the project…(sought) the participation of volunteers in that age range.
The principal investigator (was)…Dr. Juan Carlos Zevallos, director of the Clinical Research endowment Health Services from the Medical Sciences School.
Through this study, UPR seeks to educate people on identifying the symptoms of dengue fever, what to do if they suspect that they have the infection and, above all, how creating the first vaccine to prevent dengue infection could benefit society.
The estimated cost of hospitalization in Puerto Rico due to dengue is $1,500 to $ 1,800 per patient, according to UPR statistics. In the epidemic of 2007, about 5,000 patients were hospitalized.
UPR estimates that an investment of $10 million ($2.50 per person on the island) on larvae control would help reduce dengue transmission by 50 percent…
Flightless mosquitoes bred to fight malaria and dengue fever | byDAILY MAIL REPORTER
Mosquitoes have been genetically engineered so they cannot fly, in an effort to stop diseases such as malaria and dengue fever from spreading.
British scientists said mixing lame females with the native mosquito population could suppress the disease-spreading insects…
The team from UK biotechnology firm Oxitec, have concentrated on mosquitoes that carry dengue fever…
The scientists altered the blood-sucking insects’ genes to disrupt development of their wing muscles.
The genetic modification grounded only the virus-carrying females and did not affect the males’ ability to fly, they wrote in the Proceedings of the National Academy of Sciences…
Inverness Medical Innovations, Inc. (IMA) Introduces New Early Rapid Test For Dengue Fever
Inverness Medical has…announced the launch of the new Panbio® Dengue Early Rapid immunochromatographic test for the early detection of dengue infection. Designed for use in conjunction with other dengue serology tests, the Dengue Early Rapid test can help to diagnose active dengue infection from the very first day fever appears. In facilitating early diagnosis, therapy and monitoring can begin much earlier, reducing the risk of severe complications such as dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS).
Detecting dengue NS1 antigen in serum, the Dengue Early Rapid test is able to provide a specific diagnosis of dengue infection in 15 minutes following an easy three step procedure. This is especially valuable in areas where diagnosis could be confounded by serological cross reactivity.
UNASUR Health Council promotes training and research
VHeadline commentarist, Guyana’s Ambassador to Venezuela, Dr. Odeen Ishmael writes:
…The problem of dengue is regarded as one of critical importance, and UNASUR countries are already coordinating joint activities to combat this disease.
At the previous Council of Health meeting in Quito in August 2009, an important bilateral discussion between the Health Ministers of Argentina and Bolivia led to an agreement to institute a plan to combat dengue in the region along their common border. According to the Argentine Minister, the plan was seen as “a joint undertaking to combine efforts and share experiences.”
- Last year, Argentina faced the biggest dengue epidemic in its history, with more than 50,000 people becoming infected.
…One such exemplary program is the cross-border collaboration begun in 2000 when Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Suriname, and Venezuela joined together with support from the Amazon Malaria Initiative, spearheaded by PAHO and the US Agency for International Development (USAID). Responding to World Health Organization (WHO) findings that malaria parasites had developed resistance to traditional anti-malarial drugs, the countries formed the Amazon Network for the Surveillance of Anti-malarial Drug Resistance (RAVREDA) to assess the development of drug resistance in the Amazon Region. RAVREDA documented the growth of resistance to single-drug treatments, and the countries then collectively introduced specialized combination therapies to replace them.
A significant result of this form of cooperation is the current cooperation agreement instituted by Guyana, Brazil and Venezuela to provide vaccines and medications to combat malaria and other tropical diseases in their hinterland areas, and especially along their common tri-border region.
| La Jolla Institute for Allergy and Immunology Scientists Prove Hypothesis On The Mystery Of Dengue Virus Infection |
A leading immunology research institute has validated the long-held and controversial hypothesis that antibodies – usually the “good guys” in the body’s fight against viruses – instead contribute to severe dengue virus-induced disease, the La Jolla Institute for Allergy & Immunology announced today. The finding has major implications for the development of a first-ever vaccine against dengue virus, a growing public health threat which annually infects 50 to 100 million people worldwide, causing a half million cases of the severest form.
“Our lab has proven the decades old hypothesis that subneutralizing levels of dengue virus antibodies exacerbate the disease,” said La Jolla Institute scientist Sujan Shresta, Ph.D, noting this occurs in people with secondary dengue virus infections who have antibodies to the virus due to a previous infection. “This is a situation where antibodies can be bad for you, which is counter to everything we know about the normal function of antibodies. It also presents a special challenge for researchers working to develop a dengue virus vaccine, since most vaccines work by prompting the body to produce antibodies.”…
The dengue virus antibody phenomenon, termed antibody-dependent enhancement of infection (ADE), was first hypothesized in the 1970s by Scott Halstead, M.D., a renowned scientist and one of the world’s top experts on dengue virus infection. Dr. Halstead said he got his first inkling of the phenomenon while doing extensive clinical studies of dengue virus patients in Thailand in the 1960s. “We were able to detect that the severe patients all had a secondary antibody response, meaning that they had all been infected before,” he said. “That was the first evidence we had that a person had to have a previous dengue infection to get the severe disease.” Further epidemiological observations, including cases in which severe dengue virus occurred in infants born to previously infected mothers, along with lab cell studies, prompted Dr. Halstead to put forth the ADE hypothesis. Dr. Shresta’s work, conducted in mouse models, provides the first in vivo proof of ADE’s occurrence.
Dr. Halstead said he is pleased to see his hypothesis proven in animal studies, but actually finds Dr. Shresta’s development of a solid dengue virus mouse model even more exciting…
Additonal Resources:
New finding may help in dengue fever fight – by netdoctor.co.uk
A new study by scientists from Imperial College London has found that some of the human immune system’s defences against the virus that causes dengue fever actually help the virus to infect more cells.
The study also brings scientists closer to understanding why people who contract dengue fever more than once usually experience more severe and dangerous symptoms the second time around…
Professor Gavin Screaton, the lead author of the study from Imperial College London, and his colleagues identified a set of antibodies, produced by the human immune system to fight off the dengue virus, that they believe scientists should avoid including in any new vaccine to prevent dengue fever.
The new research shows that these precursor membrane protein (prM) antibodies do not do a very effective job of neutralising the virus. Moreover, these antibodies actually help the virus to infect more cells.
The study suggests that when a person who has already been infected with one strain of dengue virus encounters a different strain of dengue virus, the prM antibodies awakened during the first infection spring into action again. However, rather than protecting the body from the second infection, these prM antibodies help the virus to establish itself.
This activity of the prM antibodies could explain why a second infection with a different strain of the virus can cause more harm than the first infection. The researchers believe that if a dengue virus vaccine contained prM antibodies, this could cause similar problems…
Study sheds light on dengue fever
UK scientists have improved their understanding of dengue fever in research that could aid the development of a vaccine against the tropical illness…
Scientists at Imperial College London have now identified a set of antibodies that are produced by the human immune system. Although they are supposed to help fight the dengue virus, these antibodies actually appear to help the virus to infect more cells.
The researchers say that the discovery, which is published in Science journal, may help to explain why people who catch dengue fever for a second time tend to experience more severe symptoms…
Dengue Seroprevalence Study in Blood Donors in the French West Indies (DengSeroprevAn)
Dengue is an infectious disease most prevalent in the world. This disease is endemic in the Caribbean, with an increase in seasonal rains. Several outbreaks have been observed in recent years, in 2001, 2005 and 2007, during which further particularly virulent serotypes have emerged. The clinical expression of dengue fever is variable, ranging from no symptoms to a classical form with fever, and even of severe or lethal bleeding. With the possible existence of silent forms of the disease, there are no data identifying the current level of protection of the population in Martinique / Guadeloupe…
Dengue vaccine candidates show promise | by Tatum Anderson, TropIKA.net )
Luckily, a race is under way create the first dengue vaccines. Groups from Hawaii to France, are racing to create vaccines, many supported by the Pediatric Dengue Virus Initiative (PDVI), a Gates-funded organisation (see below). But it will also be interesting to see how these vaccines will be marketed, priced and distributed in poorer countries. After all, they involve costly trials, use new technologies and require multiple doses too. And importantly, they are a potential money-spinner for the companies involved. One of the companies making a dengue vaccines reckons the market could be worth $1 billion annually. The market for travellers’ jabs alone will be 300-$400 million annually, because visitors make 50 million visits per year to dengue areas. (Over 90% of these revenues would be from American, European and Japanese travellers.)
Researchers say there must also be a more coordinated approach to the different trials and that the sharing of information on these vaccine studies should be coordinated by the WHO. TropIKA.net will follow future progress towards vaccines. Here is our rundown of selected candidates so far…
Fighting Dengue: SLU Studies Investigational Vaccine
Sponsored by the National Institutes of Health (NIH), Saint Louis University’s Center for Vaccine Development is conducting research of an investigational vaccine designed to prevent people from contracting dengue, a potentially lethal virus that has rapidly spread around the world.
“Finding a safe and effective vaccination for dengue is a global health priority,” said Sarah George, M.D., assistant professor in the division of infectious diseases at Saint Louis University and principal investigator of the study…
The clinical trial is the first research in humans of DENVax™, a dengue vaccine developed by Inviragen Inc., with support from NIAID, the Pediatric Dengue Vaccine Initiative and the Centers for Disease Control and Prevention (CDC). Inviragen’s dengue vaccine, invented by researchers at the CDC’s Division of Vector Borne Infectious Diseases, is based on a safe and weakened dengue virus that has been demonstrated to generate long-lasting anti-dengue immune responses against one of the four dengue viruses. The investigational vaccine is designed to protect people from all four closely related dengue viruses…
CAN AFRICA’S MALARIA DRUG COME FROM COMMON HERBS? | WRITTEN BY SADE OGUNTOLA, THURSDAY, 08 JULY 2010
In Nigeria, malaria is a major contributory factor and a leading cause of death among all age groups. It accounts for more than 25 to 30 per cent of all cases of death among children less than five years of age, and is a major cause of poverty. What’s more, quite a number of pregnant women are affected annually, as these groups of people are the most vulnerable to the disease.
Despite the magnitude of the disease in developing countries, modern medicines are often not available and where available, the cost is often beyond the reach of the poor people in most of the nation’s rural areas. Professor Oladimeji Oladepo, Dean, Faculty of Public Health, University of Ibadan, in an assessment of how the poor have access to quality anti-malarial drugs, found that all they often have access to are those antimalarials sold by patent medicine vendors and these are merely cheap, ineffective drugs.
Their plight is further compounded by the rapid spread of malaria parasite; resistance to drugs has made malaria treatment more difficult and less successful, thus making the use of herbs in case management of malaria more popular, and the need to search for more potent, affordable and cost effective alternative, very urgent.
However, the efficacy of the various herbal treatments given by the traditional health care provider depends to a large extent, on the knowledge of the various aspects of the disease, diagnostic methods and treatment options. This, however, varies from one part of the African continent to another.
Several surveys have substantiated this fact, and one of such is that carried out by researchers from the University of Ibadan, which was able to establish that from one part of Nigeria to the other each locality had its unique herbs that work both for the prevention and the treatment of malaria.
In the Middle Belt of Nigeria, for example, they examined treatment practices for febrile illnesses among 185 traditional healers. With the aim of enhancing traditional healers treatment practices for febrile illnesses, especially malaria. It became was obvious that many herbs can be Africa’s candidate for malaria drug of the future. The 2005 study was published in the in African Journal, Traditional, Complementary and Alternative Medicines.
The traditional healers listed 164 plants used in the preparation of the various malaria treatment modalities. Of these 12 plants were identified to be commonly used for the treatment of illnesses brought to the healers. These include Azadirachta indica or neem, Erythrina senegalensis, (coral tree or coral flower) Ocimum basilicum or basil ; Ficus thonnigii (fig tree); Bridelia micrantha, Cassia alata; Cassia occidentalis (negro coffee); Jatropha curcas (Physic or Barbados nut); and Annona senegalensis (wild custard apple).
One of such herbs used to treat malaria, whose safety limits have been ascertained, is Enatia chlorantha. This is a herb that bears different local names in Nigeria. The stem bark of this plant, also known as African yellow wood among the Yoruba speaking community, is called “Iyani” or “Awopa,” while in Benin, it is called “Evenbavbogo”
This plant is well distributed in the southern part of Nigeria, West Cameroun, Gabon, Angola and Zaire, and its bark has been used differently in the treatment of various diseases in different communities across Africa.
The study on the cummulative effects of using Enatia chlorantha decoction to treat malaria fever by researchers from the University of Ibadan confirmed that it was effective against malaria fever and jaundice in the 120 mice that were used in the laboratory study…
After more than a decade of development at the National Institutes of Health, a vaccine to prevent infection by the mosquito-borne dengue virus has begun human clinical testing. The vaccine was developed by scientists at the National Institute of Allergy and Infectious Diseases (NIAID) and is undergoing clinical study at the Johns Hopkins Bloomberg School of Public Health in Baltimore.[...]
“This is an important milestone for NIAID’s intramural scientists in the development of a model dengue vaccine, which could potentially have a major impact in preventing dengue,” says NIAID Director Anthony S. Fauci, M.D. “With increasing infection rates and disease severity around the world and the discovery of dengue in parts of Florida, finding a way to prevent dengue infection is an important priority.”
Dr. Fauci is co-author of a 2008 commentary in the Journal of the American Medical Association that raised awareness of dengue as an emerging infectious disease.[...]
“Controlling the mosquito vector can work, but it is very expensive and difficult to sustain,” says Anna Durbin, M.D., who is leading the study at Johns Hopkins. “In the long run, vaccination would be a more efficient and cost-effective approach.”
The new vaccine is tetravalent, meaning that it is designed to protect against all four dengue viruses, also called serotypes. This is especially important because of the way the immune system responds. A person who develops antibodies against one serotype of dengue virus is protected against only that specific serotype. To be fully protected against the four forms of dengue, a person must have antibodies against all four serotypes of the virus. However, having some antibodies to dengue may be worse than having none: Someone who has antibodies against only one or a few of the virus serotypes is actually at higher risk of developing the severe form of the disease upon infection by another serotype. But a person who is immune to all four serotypes cannot be reinfected, and, therefore, is less likely to develop DHF/DSS.
Development of the vaccine was led by Stephen S. Whitehead, Ph.D., and Brian Murphy, M.D., of NIAID’s Laboratory of Infectious Diseases. The researchers started by testing seven monovalent vaccines, each of which is designed to protect against a single dengue serotype.
“Our overall strategy was to identify the best individual candidate for each serotype, based on safety and ability to induce an immune response, and to then combine those into a tetravalent vaccine,” explains Dr. Whitehead. To optimize the immune response to each dengue serotype, the researchers are testing three different candidate combinations of the four monovalent vaccines.
In this Phase 1, study volunteers who have never been exposed to dengue were randomly assigned to receive one of the candidate tetravalent vaccine formulations or a placebo. The candidate vaccines are live-attenuated, or created by making the live virus harmless or less virulent.
Evaluation of a second candidate combination vaccine has been initiated at the University of Vermont in Burlington, and trials of the third candidate will begin shortly thereafter at Johns Hopkins. These early clinical trials are designed to test the vaccine’s safety and ability to stimulate immune responses in healthy adults ages 18 to 50. After a baseline assessment, participants will receive one dose of the assigned vaccine or placebo. At follow-up study visits over the next six months, the researchers will assess their health and dengue symptoms and collect blood and urine samples for analysis. After determining which tetravalent vaccine is most promising, the researchers will test that candidate in a trial in a new group of volunteers in Brazil, where dengue has become highly prevalent.
The next stage of testing, a Phase II trial, will involve more participants and will test for differences in preliminary signs of effectiveness between people who have been exposed to dengue and those who have not, as well as the need for a booster shot within a few months of the initial vaccination. “If everything goes well after that stage, we hope to start the final phase of human testing in three to four years,” says Dr. Durbin.
For more information, visit NIAID’s Dengue Fever Web portal.
THING YOU DID NOT KNOW ABOUT MOSQUITOES.... It would take 1,200,000 mosquitoes, each sucking once, to completely drain the average human of blood. (Sources: discovermagazine.com / anannimos.blogspot.com) - Now you know.
