Feb 4, 2011
H5N1 hits more poultry in Japan, Bangladesh
Japanese officials have confirmed an H5N1 avian influenza outbreak at a poultry farm in Oita prefecture, raising the number of recently affected prefectures to five, Kyodo News reported today. Authorities culled about 8,100 chickens at the farm in Oita city, along with 5,000 at a meat processing center in Usa. About 2,000 chickens from the farm had been sent to the processing center. Oita prefecture, in southwestern Japan, borders Miyazaki prefecture, which has recently reported outbreaks at seven farms.
Elsewhere, the H5N1 virus has struck two more poultry farms in Bangladesh. An outbreak at a commercial farm near Narayangonj district in Dhaka division that was detected on Jan 24 killed 1,500 poultry, and officials culled nearly 8,500 more birds to stop the spread of the disease, according to a report yesterday from the World Organization for Animal Health (OIE). Yesterday livestock officials in the Kishoreganj district of Dhaka division culled 7,000 chickens at a commercial farm after tests on birds that died suddenly revealed avian flu, the Daily Star, a newspaper based in Dhaka, reported today.
Feb 3 OIE report
Feb 4 Daily Star story
Most drug-resistant novel H1N1 cases in Japan linked to antiviral use
The vast majority of oseltamivir (Tamiflu)-resistant pandemic 2009 H1N1 cases in Japan were linked to taking the drug, with little human-to-human transmission of resistant viruses, says a study published today in Emerging Infectious Diseases. Researchers analyzed 4,307 clinical specimens using neuraminidase sequencing or inhibition assays and found 61 oseltamivir-resistant cases. Of those, 55 patients (90%) had received the drug, 45 as treatment and 10 for prevention. The authors said this likely means that most cases emerged sporadically because of selection pressure. They found no evidence of sustained transmission of resistant viruses but reported two suspected instances of human-to-human transmission.
Feb 4 Emerg Infect Dis study
New mosquito subspecies seen as potential malaria spreader
Scientists have discovered a new subspecies of mosquito in Burkina Faso that is susceptible to the malaria parasite and prefers to live outside, thus potentially circumventing traditional malaria-control measures like mosquito netting. The team of researchers collected Anopheles gambiae larvae and adult mosquitoes—known to carry Plasmodium falciparum, which transmits malaria to people—in the west African nation, according to their study published today in Science. They found that 57% of larvae collected from puddles were genetically very distinct from adult mosquitoes trapped in homes in nearby villages and that cross-breeding between the groups was unlikely. This is significant, because much malaria prevention occurs in homes, with insecticide spraying and use of bed nets. In addition, when the larvae of the new subspecies—christened Goundry after a local village—were fed blood containing P falciparum, 58% became infected, compared with 35% for the home dwellers. Co-author Kenneth Vernick of the Pasteur Institute in Paris said this finding suggests the Goundry subgroup may contribute considerably to malaria transmission to humans, according to an accompanying Science news story. However, the researchers didn't catch adult Goundry mosquitoes, so they don't yet know whether they bite people.
Feb 4 Science abstract
Feb 4 Science news story on the study
New drug helps prevent C difficile re-infections
A new antibiotic cures Clostridium difficile infection as effectively as current treatment and prevents recurrence better, according to a study published yesterday in the New England Journal of Medicine. In a phase 3 trial conducted by Canadian and US researchers, 629 patients were randomly assigned to treatment with fidaxomicin, the new drug, or vancomycin, a common drug of choice. Fidaxomicin had a clinical cure rate of 88.2%, compared with 85.8% for vancomycin by one measure (modified intention-to-treat analysis), and a cure rate of 92.1% versus 89.8% for vancomycin by another (per-protocol analysis). Patients taking the new drug also had a significantly lower rate of recurrence of the infection, in both the modified intention-to-treat analysis (15.4% to 25.3%, P=0.005) and the per-protocol analysis (13.3% to 24.0%, P=0.004). "Anybody who knows C difficile recognizes that recurrences are the major problem with this disease," said co-author Dr. Mark A. Miller of the Jewish General Hospital in Montreal in a press release, pointing out how difficult recurrences are to treat. "Anything that can reduce the recurrence rate, especially as dramatically as fidaxomicin, is a very important milestone in the treatment of C difficile." In recent years C difficile infections have become more common and increasingly virulent, according to the study's authors.
Feb 3 N Engl J Med abstract
Feb 2 press release on the study