Update on Avian Influenza in 2006
In the first quarter of 2006, bird flu panic was in full swing: The French feared for their foie gras, the Swiss locked their chickens indoors, and Americans enlisted prison inmates in Alaska to help spot infected wild birds.
The H5N1 virus — previously confined to South East Asia — was striking birds in places as diverse as Germany, Egypt, and Nigeria, and a flu pandemic seemed inevitable. Then the virus went quiet. Except for a steady stream of human cases in Indonesia, the current flu epicenter, the past year’s worries about a catastrophic global outbreak largely disappeared.
Part of the explanation may be seasonal. Bird flu tends to be most active in the colder months, as the virus survives longer at low temperatures.
Some experts suspect poultry vaccination has, paradoxically, complicated detection. Vaccination reduces the amount of virus circulating, but low levels of the virus may still be causing outbreaks without the obvious signs of dying birds, masking it harder to see what is happening in animals and humans.
While the pandemic has not materialized, experts say it’s too early to relax.
Flu viruses constantly evolve, so the mere appearance of mutations is not enough to raise alarm. The key is to identify which mutations are the most worrisome.
In May 2006, on Sumatra island in Indonesia, a cluster of 8 cases was identified, 6 of whom died. Luckily, the Sumatra cluster was confined to a single family. Though human-to-human transmission occurred — as it has in a handful of other cases — the virus did not adapt enough to become easily infectious.
Scientists are bracing themselves for increased bird flu activity in the winter; there are no predictions about where it might appear next.
Since 2007 there has been identified four human cases in Indonesia with two deaths and 1 in China and I in South Korea. Avian H5N1 has been found in wild birds in Hong Kong, and in poultry farms in Nigeria and Japan.
Total number of human cases 264 and deaths is 158 ( as of 1/12/06)with a steady high mortality rate of 60 and affecting age groups below 40 years of age.
The H5N1 viruses have been around since 1990’s and it might be tempting to conclude that if they were going to proceed to form or contribute to a pandemic strain, they would have done so by now. However, it should be remembered that the avian influenza virus which contributed to the 1918-19 ‘Spanish Influenza’ H1N1 pandemic strain had been around for some years before it became part of a virus that could efficiently transmit between humans.
Evidence has accumulated suggesting that both poultry and wild bird populations have played a significant role in the recent virus evolution and spread. The EU animal experts have tightened rules for the import of live captive birds as part of the bloc’s strategy to fight bird flu.
Latest update on Oeseltamivir
The US Food and Drug Administration (FDA) and Roche Laboratories Inc have notified healthcare professionals in December 2006 regarding safety labeling revisions for oseltamivir phosphate (Tamiflu capsules and suspension) that warn of the potential risk for neuropsychiatric events associated with its use.
The warning suggess that patients with influenza receiving oseltamivir, particularly children, may be at increased risk for self-injury and delirium.