Viral Fusion Inhibitors

A recent study by researchers at the University of Utah determined that the 2009 pandemic influenza A (H1N1) caused a higher rate of neurological complications in children than the seasonal flu. The most common complications observed were seizures and encephalopathy. Full details of the study, the most extensive evaluation of neurological complications following H1N1 flu in children, are published in the September issue of Annals of Neurology, a journal of the American Neurological Association.

The H1N1 virus (swine flu) was identified in Mexico and the U.S. in April 2009 and quickly spread worldwide, prompting the World Health Organization (WHO) to declare the novel influenza A virus a pandemic. According to estimates from the Centers for Disease Control and Prevention (CDC), 43 million to 89 million Americans were infected with H1N1 between April 2009 and April 10, 2010, with approximately 14 million to 28 million of those cases in children 17 years of age and younger. On August 10, 2010 the WHO International Health Regulations Emergency Committee officially declared an end to the 2009 H1N1 pandemic.

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West Nile virus tricks mosquitoes into producing a particular protein complex that allows it to survive and be transmitted, Yale researchers report in the Sept. 3 issue of the journal Cell.

This molecular survival mechanism helps explain how West Nile virus got a foothold for the first time in North America nearly a decade ago, note the researchers. And as temperatures rise in the hemisphere, this mechanism may help public health officials in traditionally temperate climates identify emerging threats from tropical diseases, they add.

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Colorado State University researchers have discovered that mosquitoes that transmit deadly viruses such as dengue avoid becoming ill by mounting an immediate, potent immune response. Because their immune system does not eliminate the virus, however, they are able to pass it on to a new victim.

In a study published February 13 in the open-access journal PLoS Pathogens, the researchers show that RNA interference – the mosquito immune response — is initiated immediately after they ingest blood containing dengue virus, but the virus multiplies in the mosquitoes nevertheless.

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Dengue fever — caused by a virus transmitted by mosquitoes — threatens 2.5 billion people each year and there is no vaccine or treatment. New research by Michigan State University entomologists has found that a bacterium can stop dengue viruses from replicating in the mosquitoes.

“In nature, about 28 percent of mosquito species harbor Wolbachia bacteria, but the mosquitoes that are the primary transmitters of dengue, Aedes aegypti, have no Wolbachia in them,” said Zhiyong Xi, MSU assistant professor of entomology and study author. “We found that Wolbachia is able to stop the dengue virus from replicating. If there is no virus in the mosquito, it can’t spread to people, so disease transmission can be blocked.”

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A mosquito-borne virus that each year harms up to 100 million people and kills more than 20,000 is a step closer to being controlled after a breakthrough by Queensland scientists.

In a paper published in the prestigious international journal Science on January 2, researchers from The University of Queensland have proved the effectiveness of a new way of limiting the lifespan of the type of mosquito that spreads dengue fever.

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Research published this week in PLoS Medicine demonstrates associations between local rainfall and temperature and cases of dengue fever, which affects an estimated fifty million people per year worldwide. But the study finds little evidence that the El Niño-Southern Oscillation – the climate cycle that occurs every three to four years as a result of the warming of the oceans in the eastern Pacific – has a significant impact on the incidence of dengue in Mexico, Puerto Rico or Thailand.

Large outbreaks of dengue, a vector-borne viral disease spread by the Aedes aegypti mosquito, occur every few years in many tropical countries. Michael Johansson, of the Centers for Disease Control and Prevention in Puerto Rico, used a technique called “wavelet analysis” to probe relationships between the local climate, El Niño, and incidence of dengue in Mexico, Puerto Rico and Thailand — three countries where dengue is endemic. They were able to separate and compare seasonal and multiyear components of each. In all three countries temperature, rainfall, and dengue incidence varied strongly on an annual scale, showing association in the wavelet analysis.

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