Weekly Topic: ASF outbreak update - 3rd case reported
Another outbreak of ASF occurred August 19th in Haizhou District of the city of Lianyungang, in the Jiangsu Province. This marks the third reported outbreak of ASF in China.
Lianyungang is approximately 800 miles from the initial reported cases in Liaoning Province (Aug 3rd) and approximately 350 miles from the second reported case in Henan Province (Aug 16th).
On August 15th, a farm in the Haizhou District started reporting unexplained deaths in pigs. A total of 615 cases were reported: 88 died due to ASF and 527 were killed and disposed. None of the pigs were reported as slaughtered. In total nearly 10,000 pigs have been culled as an attempt to contain the outbreaks. More than 8,000 pigs were culled in Liaoning, 1,362 culled in Henan, and 527 in Jiangsu.
This case marks the third reported province affected by ASF with the addition of a 4th province, Heilongjiang, where live infected pigs traveled to Henan province, the site of the 2nd reported case.
Response so far
Following the initial outbreak, local government initiated the African Swine Fever Contingency Plan and Emergency Response according to Standards & Protocols for African swine fever. There is no current known source or origin of the outbreaks.
Strict blockades, disinfection, killing and disposal of the animals and relevant contaminated material, and movement control measures are being conducted. As of August 14th, over 35 million pigs have been screened and over 10,000 samples were collected. In key provinces such as Beijing, Tianjin, Hebei, Inner Mongolia, Liaoning, Jilin, Heilongjiang, Guangdong, Gansu, and Xinjiang, epidemiological surveys and emergency surveillance is being conducted.
In accordance with the contingency plan and emergency response, the area extending 3km from the edge of the infected premise (IP) is designated the epidemic zone. In accordance with guidelines, all pigs located in the IP and epidemic zone are culled and disposed of properly. Strict blockages, disinfectant and movement controls, and 8 disinfectant checkpoints are have been set up in the epidemic zone. Entry and exit of farm and backyard machinery must be through these checkpoints. In addition a complete ban on an pigs, pig product, or possible contaminated material from IP and epidemic zone is in place.
As there is no vaccine available for ASF rapid identification, elimination by culling and disposing of all infected material along with any potentially infected pigs, and biosecurity are key factors in controlling and eliminating disease.
An unknown source
African swine fever is endemic in many African countries. It first was reported in Kenya in the 1920’s later spreading to multiple countries in Europe. Through eradication programs, many European countries were able to eradicated the virus but it is still present in Eurasia and Russia.
Researchers at the Institute of Military Veterinary Medicine and other institutes collected tissue samples from two deceased pigs on one of the affected farms in Liaoning province. Genetic analysis revealed that it closely resembled virus strains isolated in Eastern Europe and Russia. It is important to note this does not provide an answer to the exact source of infection as the pan-Russia is also the strain which was originally introduced from East Africa.
Interestingly, other reports suggest that ASF may have been occurring as early as April. ASFV RNA was found in stool samples on a farm in Liaoning province, which sold piglets on July 5th to the farm with the first recorded ASF outbreak. When interviewing the farm selling the piglets, they reported that the last entry of piglets onto their farm was March 24th, and some of those piglets became sick and died. They reported no abnormal deaths and sold the remaining piglets to the farm which later reported the first outbreak.
Other reports also state farms affected by ASF in Lianoing province have been reported to be feeding swill since mid-June to their herds, and 400 pigs developed clinical signs consistent with ASF. All 400 pigs died within a 1 month period and the farm was abandoned.
Other compounders are China’s ever increasing demand for pork, which has led to an increase in live pigs and pork products. This, along with Illegal imports and improper biosecurity, can be difficult to mitigate, increasing the risk of disease spread. Another concern is the illegal sale of moribund pigs to be slaughtered, resulting in possible spread of ASF.
Questions, comments, feedback about today's Weekly Update? Please email Dr. Gus Brihn
Receive the Weekly Update right in your inbox on Tuesdays and Thursdays. Subscribe now at z.umn.edu/WeeklyUpdateSubscribe