Highly pathogenic avian influenza (HPAI) virus re-emerges in Thailand

Thousands of chickens were culled last week after the highly pathogenic avian influenza (HPAI) virus was found at The North Regional Veterinary Research and Development Center by Thailand's Department of Livestock Development.

The description of the infected population was described as, "Layer, broiler, duck, goose, ostrich, native chickens, in ventilated houses located in the same cluster".

Yukol Limlamthong, the department's director general stated that 1,575 chickens at the research farm of Chiang Mai University were incinerated after a laboratory test comfirmed that some chickens were infected with the H5N1 virus that causes bird flu.

Yukol said the disease from the isolated area did not spread to the farms nearby and no officials working in the research farm had contracted the disease.

The Thai government confirmed the outbreak of bird flu epidemic on Jan. 23. Over the last few months 39,111,059 fowls have either died of the disease or were culled.

The causative agent is the avian influenza (AI) virus. AI viruses all belong to the influenza virus A genus of the Orthomyxoviridae family and are negative-stranded, segmented RNA viruses.

Avian influenza spreads in the air and in manure. Wild fowl often act as resistant carriers, spreading it to more susceptible domestic stocks. It can also be transmitted by contaminated feed, water, equipment and clothing; however, there is no evidence that the virus can survive in well cooked meat.

The incubation period is 3 to 5 days. Symptoms in animals vary, but virulent strains can cause death within several days.