US bird flu virus seen under control within a few months

PARIS (Reuters) - An epidemic of bird flu that has devastated US poultry flocks this year is likely to be under control within a few months as the United States steps up measures to contain the virus and the summer weather weakens it, senior officials said on Tuesday.

There is, however, a high risk that bird flu strains could spread within the American continent, mainly Mexico, the head of the Paris-based World Organisation for Animal Health (OIE) said, calling farmers and authorities to boost biosecurity measures.

The US poultry industry is confronting its biggest recorded outbreak of bird flu, which has led to the death or culling of more than 40 million birds after confirmation on commercial farms and backyard flocks in 16 U.S. states and in Canada.

The disease, which manifests in several physical symptoms and a sharp drop in egg production, has led to a sharp rise in egg prices, forcing food producers to look for alternatives. "I think it cannot worsen in the United States," OIE Director General Bernard Vallat told Reuters in an interview. "Given the scale of the damage and the pressure on farmers I believe they will quickly protect themselves more efficiently. There are huge economic stakes here." He said he expected the epidemic to be under control by September.

The US chief veterinary officer John Clifford was more optimistic, putting the end of the epidemic at July, taking account of a recent decline in the number of cases and warmer weather that lowers transmission. "Summertime is coming. It gets hot in these places in July and because the heat and the sunlight reduces the virus present in the environment we will stop seeing cases," Clifford said on the sidelines of OIE's general assembly in Paris.

The U.S government reported 34 outbreaks of highly pathogenic H5N2 and H5N8 bird flu on farms or backyards between April 27 and May 8, leading to the death or culling of 9.9 million birds, the OIE website showed.

However, cases have waned in the past two weeks, Clifford said. "We believe the worst is behind us, which doesn't mean that we still won't see additional cases but we know we see a decline in cases," he said.

The bird flu epidemic in the United States was particularly severe because farmers were not prepared, and because of the size of its farms, Vallat said.

Clifford stressed U.S. authorities were preparing the poultry industry for any return of bird flu later in the year. "We can't predict for sure whether it will be back in the fall in the wild bird population as they start migrating south but it's very likely that it could be present again so we need to prepare ourselves for the worse case scenario for next year." While the U.S. threat is seen fading, Vallat, who estimated that the U.S. bird flu toll could reach 50 million, highlighted risks to other countries in the region, particularly Mexico, and urged a stronger approach to biosecurity.

This included early detection and surveillance and simple steps such as protecting feed from wild birds and disinfecting everything entering farms including people, trucks and veterinarians, he said.

Outbreaks of a different strain of bird flu virus, H7N3, in Mexico in 2012 and 2013 led to the death of nearly 20 million birds over two years, data showed.