Blogs / 80beats

Flu season is taking a toll on chicken farms across Asia, where new bird flu outbreaks are cropping up from China to India, leading to massive poultry slaughters. Health officials say the chickens are infected with the deadly bird flu strain known as H5N1, but thus far there have been only a few cases of human infection. Two human cases have been reported in Indonesia, one in Cambodia, and in Egypt a 16-year-old girl died of the virus. Yi Guan, a Hong Kong microbiology professor, says the recent spate of cases across the region may not be completely isolated and would likely get worse as winter sets in, when the risks of influenza tend to peak [The Wall Street Journal].

In China, more than 370,000 chickens were culled after an outbreak was announced in the eastern province of Jiangsu. The usual precautions have been imposed: birds have been slaughtered in the surrounding area, farms quarantined and disinfected, and the transport of fowl banned. But no information has been released about the scale of the outbreak - how many birds were found to be carrying the H5N1 strain of the virus and how many of them died [BBC News]. Chinese authorities say migrating birds probably brought the virus to local farms.

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Cancer will be the world’s leading killer by 2010, edging out heart disease for the top spot, according to the latest report by the World Health Organization (WHO). Though cancer rates in the United States have just recently begun to decrease, elsewhere in the world cancer is on a steady rise. Experts cite tobacco, increasingly Western lifestyles, and inadequate medical care as the factors contributing to the cancer epidemic in developing countries. “In the U.S., we pay a lot of attention to cancer trends, and the trend has been encouraging,” says Dr. Richard Schilsky… “But we have forgotten that there is a big wide world out there. Cancer is a global problem” [TIME].

According to the WHO report, 12 million new cases of cancer will be diagnosed this year and 7 million will die from the disease. The group forecast a 1 percent increase globally each year, with emerging economies such as China, Russia and India being hit the hardest [CNN]. The report also projects a 38 percent population increase in less developed countries by 2030. Taken together, that means by 2030 an estimated 20 to 26 million new cases of cancer will be diagnosed annually and 13 to 17 million deaths will be cancer-related.

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Firing new shots in the malaria war, a vaccine still in the testing stage is now a step closer to becoming a public health reality [Science News]. Two field trials in Kenya and Tanzania showed that the experimental drug reduced malaria infections by more than 50 percent in infants and young children; if a final set of trials proves that the vaccine is indeed safe and effective, the vaccine could be ready for use by 2011.

If the phase three trials are successful, it would be “an extraordinary scientific triumph,” said Dr. W. Ripley Ballou, deputy director for vaccines and infectious diseases for the Bill and Melinda Gates Foundation, which helped fund the research. But more importantly,” Ballou added, “it could save millions of children’s lives” [Los Angeles Times]. Malaria kills about 1 million people around the world each year, and most of the victims are children under the age of five.

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This week, South African health minister Barbara Hogan got her country up to speed with the rest of the world with one statement: “We know that HIV causes AIDS” [Time]. The country’s new health minister has been in office for less than a month, but she has already broken with the health policies of the previous government, which questioned the scientific consensus on HIV and AIDS, and discouraged the use of life-saving AIDS drugs.

Her pronouncement at an international AIDS vaccine conference marked the official end to 10 years of denial about the link between HIV and AIDS by former President Thabo Mbeki and his health minister Manto Tshabalala-Msimang. Activists also accused Tshabalala-Msimang of spreading confusion about AIDS through her public mistrust of antiretroviral medicines and promotion of nutritional remedies such as garlic, beetroot, lemon, olive oil and the African potato [AP]. Tshabalala-Msimang earned the nickname “Dr. Beetroot” from frustrated activists for her recommendations.

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Researchers have decoded the genomes of two different malaria parasites that plague people in Southeast Asia and South America, and say the new information will boost efforts to find a vaccine for the mosquito-borne disease. The work builds on the sequencing of the first malaria genome six years ago, when scientists tackled the most deadly malaria parasite, Plasmodium falciparum, which is endemic in Africa. By comparing the genetics of Plasmodium falciparum to that of the newly sequenced species, P. knowlesi and P. vivax, the two teams have begun to identify the different mechanisms by which each species maximizes its chances of evading the host immune system [The Scientist].

P. vivax is the main cause of malaria in Latin America and Southeast Asia, and although it’s rarely deadly researchers say it still causes plenty of misery. It’s also challenging to eradicate because it can lie dormant in the liver for months. “It makes people very sick,” says lead researcher Jane Carlton…. “It can come out of the liver weeks or months after the initial mosquito bite. That makes it a very serious risk to human health.” Vivax malaria is so debilitating that sufferers, most of whom are poor, can’t support themselves or their families. “Vivax is one of the stealth reasons that poor people can’t escape poverty,” says [tropical disease expert] Peter Hotez [USA Today].

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Researchers say they have turned a tobacco plant into a living factory that can produce individualized vaccines to fight a type of cancer known as follicular lymphoma. While similar vaccines have been grown inside animal cells, researchers say this new process is quicker and less expensive, and could carry less risk to the patient, as animal cells might hold unknown viruses [BBC News].

In the new technique, researchers took biopsies from each lymphoma patient and isolated the gene that produces tumor-fighting antibodies, which is slightly different in each person. In each case, they then used a genetically engineered tobacco virus to bring the gene into a tobacco plant, where the plant responded by turning out antibodies. One week later the tobacco leaves were picked and ground into pulp, and the antibodies were extracted. These antibodies are put into a patient newly-diagnosed with the disease, to “prime” the body’s immune system to attack any cell carrying them. If successful, this would mean the body would then recognise and destroy the lymphoma cells [BBC News].

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In a day of mixed results for Alzheimer’s research, researchers found that an experimental vaccine failed to prevent the disease’s crippling dementia, but also noted that a drug once used to treat hayfever “significantly” improves the symptoms of memory loss. The two separate studies were both published in the Lancet [subscription required], and offer a telling reminder that in medical research progress against a disease is rarely straightforward.

The first study treated patients who had already been diagnosed with Alzheimer’s with a vaccine that targeted the protein plaques that clump around brain cells in increasing numbers as Alzheimer’s progresses. The theory was that dementia could be slowed or reversed once the plaques were cleared [HealthDay News]. However, the vaccine had no effect on the patients’ slide into dementia, despite the fact that autopsies of patients who died during the study showed that the plaques had largely vanished.

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In a sign of the slow progress in the medical fight against the HIV virus and AIDS, a federal health agency has canceled plans for an ambitious clinical trial of an experimental HIV vaccine. Although this candidate vaccine was once thought very promising, researchers lost confidence in it after the failure last September of a similar candidate from drugmaker Merck & Co. that may have left some volunteers more vulnerable to HIV infection [San Francisco Chronicle].

Researchers at the National Institute of Allergy and Infectious Diseases had hoped to begin enrolling 8,500 volunteers in the vaccine trial last fall, but the trial was postponed after the Merck vaccine was shown to be failing in its two main objectives: to prevent infection and to lower the amount of H.I.V. in the blood among those who became infected…. After a safety monitoring committee detected the problems with the Merck vaccine in September, the company quickly halted its study [The New York Times].

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