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  • Chikungunya may be deadly

    Source: http://www.bloomberg.com/apps/news?p...u4&refer=india

    Chikungunya Virus May Be Deadly, Indian Doctors Say (Update2)

    By Jason Gale

    Feb. 29 (Bloomberg) -- Chikungunya, the tropical disease that spread to Europe from Asia last year, may have turned deadly, according to scientists who studied an outbreak that infected about 1.4 million people in India.

    More than 3,056 people may have died from the mosquito-borne virus in Ahmedabad in 2006, based on a comparison of the actual and expected death rate in the west Indian city of 3.8 million people, researchers said in a study in the March edition of Emerging Infectious Diseases. There is no treatment for the disease, which causes fever, rash and debilitating joint pain.

    The finding adds to evidence that a strain of chikungunya first observed on Reunion Island in the Indian Ocean in 2005, and which later spread to India and Italy, may be capable of causing more severe and sometimes fatal symptoms, said the study's authors, led by Dileep Mavalankar, associate professor at the Indian Institute of Management in Ahmedabad.

    ``The virus infection led to multiorgan failure'' and caused medical complications in some elderly patients with pre-existing diseases, Mavalankar said in an interview yesterday. A ``lot of morbidity, temporary and permanent, may have occurred due to the epidemic, which is not studied or documented.''

    Fifteen Indian states and territories, including Gujarat, the home of Ahmedabad, reported either 1.39 million confirmed or suspected chikungunya cases in 2006, according to the National Vector Borne Disease Control Programme in New Delhi. No deaths were attributed to the epidemic, it said.

    Excess Deaths

    Mavalankar and colleagues calculated the average mortality rate in Ahmedabad using official death and population records during the four years prior to the 2006 chikungunya outbreak, enabling them to calculate the expected number of deaths during the epidemic year. The actual number of deaths was 3,056 higher than expected, they found.

    ``The excess number of deaths observed during the epidemic in Ahmedabad suggests that estimates of deaths caused by chikungunya in India need to be revised,'' the authors said.

    Officials at the vector-borne disease agency didn't immediately respond to a request for comment.

    About 2,944 additional deaths occurred between August and November 2006 around the time when chikungunya peaked, the researchers said. Ahmedabad's medical officer reported 60,777 suspected chikungunya cases in 2006. No major adverse event or other epidemic occurred in the city between August and November.

    While chikungunya is ``the most plausible explanation'' for the higher mortality rate, they said other unidentified causes can't be ruled out.

    Thought-Provoking

    The ``very useful'' study doesn't prove the lethality of chikungunya, rather it provides impetus for further research, said Richard C. Russell, professor of medical entomology at the University of Sydney. ``It has provoked the thought that there may have been more undefined deaths associated with chikungunya than was otherwise recognized,'' Russell said in a telephone interview from Sydney today.

    Chikungunya, which means bent down or to become contorted in the Makonde language of southeastern Tanzania, was first described by doctors in Africa in 1953 and regularly causes epidemics in 23 countries in Africa, Asia and the Pacific.

    Researchers considered the disease self-limiting and nonfatal until the 2005-2006 outbreak on Reunion, when it was associated with at least 260 deaths in mostly elderly patients.

    The epidemic on the island, a French territory about 800 kilometers (500 miles) east of Madagascar, sickened about 235,000 of its 790,000 residents. Tourists visiting from Europe and North America were also infected, drawing international attention.

    `Smoking Gun'

    ``Historically, chikungunya has never been associated with mortality until this outbreak in Reunion,'' said Scott Ritchie, a medical entomologist at the Tropical Public Health Unit in Cairns, Australia. ``People are still waiting for the smoking gun'' and will be skeptical about fatalities until doctors can prove the way in which it kills those infected, he said.

    The Reunion outbreak gave scientist the opportunity to study the disease in more detail ``and to observe some more severe cases and excessive mortality,'' said Isabelle Schuffenecker, a biologist who helped study the epidemic for France's national reference center for arboviruses and viral hemorrhagic fevers in Lyon.

    It's possible that fatal cases had ``occurred in less developed countries where chikungunya was not the major health problem,'' Schuffenecker said in a telephone interview today. ``We have no proof that the virus was more virulent,'' she said.

    Indian researcher Mavalankar says international health authorities need to take the disease more seriously.

    ``It seems to have mutated and become more dangerous,'' he said. ``Our estimate is that about 50,000 deaths may have happened in India due to this epidemic.''

    To contact the reporter on this story: Jason Gale in Singapore at j.gale@bloomberg.net .
    Last Updated: February 29, 2008 06:28 EST
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