Nov 1, 2005 (CIDRAP News) – As the World Health Organization noted Thailand's 20th human case of avian influenza, it offered details today of the circumstances around the 50-year-old woman's infection.
The woman, from Bangkok, visited her husband on Oct 23 in Nonthaburi province, north of Bangkok, where backyard chickens had started dying a few days earlier, WHO said. She experienced symptoms Oct 26 and was admitted to the hospital Oct 29. She is still hospitalized in satisfactory condition, the agency said.
Investigators have not found any sign of respiratory illness among the patient's close contacts. Her case is the third confirmed in Thailand in the last month.
"These cases coincide with a recurrence of confirmed H5 outbreaks in poultry in six provinces, most of which are in the central part of the country, and point to the need to remain on high alert for the occurrence of human cases in all countries experiencing outbreaks in poultry," WHO wrote.
The WHO recently published suggestions to protect people from direct exposure to the H5N1 virus and, if needed, to protect people after exposure. Among the guidelines:
- Vaccinating people at risk for exposure to H5N1 against seasonal flu can reduce the chances for the virus to re-assort, which would allow the H5N1 avian virus to adapt more to people and could lead to easier person-to-person spread of the virus.
- At-risk agricultural workers should wear protective clothing, such as coveralls with an impermeable apron or surgical gowns with long, cuffed sleeves and an impermeable apron; heavy rubber gloves that can be disinfected; surgical masks (standard, well-fitted surgical masks can stand in if high-efficiency N95 masks can't be found) with fit-testing and training in mask use; goggles; and rubber or polyurethane boots that can be cleaned or used with disposable foot covers.
- People at risk for occupational exposure may be protected by prophylaxis with oseltamivir. They should also check daily for 14 days after the latest exposure for signs of fever, influenza-like symptoms, and gastrointestinal symptoms.
- Suspected case-patients must be isolated and sampled according to WHO guidelines. Samples and viruses can be shipped to WHO labs for diagnosis. Serum samples and epidemiologic data also should be collected on exposed patients.
At the federal level, the US Department of Agriculture (USDA) last week outlined a number of measures to safeguard domestic poultry populations and track any avian flu viruses in the United States. In a technical briefing on avian flu on Oct 26 in Washington, DC, five people representing aspects of avian flu surveillance and prevention efforts spoke about the issues.
The USDA's Animal and Plant Health Inspection Service (APHIS) has conducted an outreach campaign dubbed "Biosecurity for the Birds" to reach poultry industry members with protective measures for their birds. In addition, USDA's collaboration with state agriculture departments allows it to monitor live bird markets in the northeastern US to stop any H5 or H7 virus subtypes found in those markets, said Dr. Ron DeHaven, APHIS administrator.
If an unusual outbreak is suspected, USDA can get specially trained veterinarians to the site within 4 hours, DeHaven added. State-level teams are usually able to respond to a suspected outbreak within a day to cull, quarantine, and disinfect. APHIS also has avian flu vaccines for poultry, which can be used in some situations.
"We do indeed have a (poultry) vaccine that is effective against the H5N1 virus that's currently circulating in parts of Asia," DeHaven added.
Although H5N1 has not been found in North America, "the expanding global spread of H5N1 increases the likelihood that it will eventually be detected here," said Richard Kearney, wildlife program coordinator at the US Geological Survey in the Interior Department.
USDA is working with the Alaska Fish and Wildlife Service (AFWS) and the USGS to address that possibility, Kearney said. FWS and USGS biologists have been sampling migratory birds in Alaska for H5N1, which bolsters other ongoing avian flu studies. A program for 2006 will include more comprehensive surveillance and detection to provide an early warning if migratory birds carry H5N1 into North America.
Dr. Richard Raymond, undersecretary for food safety at USDA, said the US inspection system ensures poultry is free from visible signs of disease.
"If high-path avian influenza were to be detected in the United States, I want to assure the American public that the chance of that infected poultry ever entering the food chain would be extremely low," Raymond said.
WHO news release on Thailand case
WHO news release on measures to stop the spread in new outbreaks
USDA news release on US response to avian flu