Signaling a shift in the H7N9 avian influenza away from the low-pathogenic strain, China's agriculture ministry said the highly pathogenic form of the virus has been detected at live-bird markets in Guangdong province for the first time.
Elsewhere in the world, avian flu outbreaks continued to exact a heavy toll on European poultry, with Bulgaria and France reporting large culls, and Nigeria reported more highly pathogenic H5N1 outbreaks, according to a news report and the latest updates from the World Organization for Animal Health (OIE).
High-path H7N9 in China
China's detection of highly pathogenic H7N9 in poultry markets was noted in a Feb 18 report to the OIE that appeared on the group's Web site today. Since it was first detected in early 2013, the novel virus has circulated in poultry as a low-pathogenic strain, which has made it difficult for animal health officials to identify outbreaks. Often, human illnesses have been sentinels that the virus is present in local poultry, especially at live-bird markets.
However, over the weekend the Guangdong province Center for Disease Control said two recent samples in humans showed mutations that suggest H7N9 may be becoming more pathogenic in birds.
The announcement was followed by a report from Taiwanese health officials, who found similar changes in a virus sample from an imported human H7N9 case, as well as a mutation in the neuraminidase protein linked to oseltamivir (Tamiflu) resistance.
In today's OIE report, China's agriculture ministry said the market birds in Guangdong province had subclinical infection. Samples from the birds sent to the national avian influenza reference lab by Guangdong officials were positive for highly pathogenic H7N9.
Authorities have closed the affected live-poultry markets and have stepped up surveillance throughout Guangdong province.
Bulgaria H5 outbreaks strike poultry, other birds
Meanwhile, Bulgaria reported a handful of highly pathogenic H5 outbreaks in January and February, suspected to be part of wider H5N8 activity across Europe over the past few months. Today in a report to the OIE the country's agriculture ministry confirmed 57 more outbreaks, mostly on farms but also involving backyard poultry and wild birds.
The latest outbreaks began between Dec 20 and Feb 8, with most of the farm events located in the central, southern, and western part of the country and many of the wild bird detections in the east along the Black Sea coast. Affected locations include 37 poultry farms, 8 backyard poultry holdings, 6 nature parks, 5 other locations where wild birds were found dead, and a zoo in Sofia, Bulgaria's capital.
All told, the virus killed 9,438 poultry, and 548,587 were destroyed to curb the spread of the virus. Wild bird deaths mainly affected swans, but other species included a buzzard, geese, and sparrows.
In France, government officials have ordered the culling of all 600,000 remaining ducks in the hard-hit Landes department in the country's southwest, Agence France-Presse (AFP) reported today. Authorities have already culled 1.9 million ducks and geese, and avian flu outbreaks have killed another 1.3 million.
France has been battling outbreaks of H5N8, along with other strains, since November. The area targeted for preemptive culling produces 25% of France's foie gras. The same region was hit by similar outbreaks in the winter of 2015-16.
In other European developments, based on the latest OIE reports:
- Germany reported 23 more H5N8 outbreaks, mainly involving wild birds, but 3 of the locations were poultry farms, 3 were backyard holdings, and 1 was a zoo in the city of Stettfeld in Bavaria state. The outbreaks began from Feb 7 to Feb 20 and affected locations throughout a large portion of Germany. The virus killed 631 poultry and led to the stamping out of 138,142 more.
- Spain reported detecting H5N8 in a white stork found dead on Feb 20 at a nature park in Catalonia in the east.
H5N1 in Nigeria
Nigeria confirmed eight more highly pathogenic H5N1 outbreaks in poultry, according to two reports today from the OIE. One detailed an outbreak at a broiler farm in Edo state in the south that began on Feb 10, killing 10 of 8,100 susceptible birds.
The second report described seven farm outbreaks that began between Feb 8 and Feb 15, mainly on farms housing layers and pullets in Kaduna and Plateau states in central Nigeria. Combined, the virus killed 2,300 of 50,683 susceptible birds. Authorities culled the remaining birds as part of the outbreak response.
Feb 18 OIE report on H7N9 in China
Feb 20 CIDRAP News story "H7N9 analyses hint at genetic mutations, drug resistance"
Feb 21 OIE report on H5 in Bulgaria
Feb 21 AFP story
Feb 21 OIE report on H5N8 in Germany
Feb 21 OIE report on H5N8 in Spain
Feb 21 OIE report on one H5N1 outbreak in Nigeria
Feb 21 OIE report on seven H5N1 outbreaks in Nigeria