As African swine fever (ASF) becomes ever more widespread in European wild boar, the region’s food safety agency has proposed an exit strategy to guide national disease eradication efforts.
Looking toward a future free of African swine fever (ASF), surveillance strategies have been developed to help countries ascertain when ASF has ceased to affect wild boar.
In a “scientific opinion” published this month, the European Food Safety Authority (EFSA) set out a two-phase approach to achieve evidence of the absences of the ASF virus in a wild population.
EFSA’s ASF exit strategy involves a phase of routine surveillance followed by a limited period of intensive surveillance. Essentially, these correspond to a screening phase followed by one of confirmation.
In developing its Scientific Opinion, EFSA studied the role of seropositive wild boar in the persistence of ASF. Among the findings is that seroprevalence declines more slowly in adults than in younger animals. Furthermore, the model suggests that it could take more than two years after the last detection of the virus for the seroprevalence in adult wild boar to reach zero.
From its modeling, EFSA shows how the exit strategy could be applied effectively in practice to affected areas large and small.
German wild boar total exceeds 800
This month, the number of wild boar in Germany testing positive for the ASF virus has surpassed 800. According to the national veterinary agency, the Friedrich-Loeffler Institute, the total stood at 825 as of March 12. This is an increase of 47 over one week.
With 751 confirmed cases since September 2020, the eastern state of Brandenburg continues to be the worst-affected state. Positive cases have been detected in five districts, including most recently Dahme-Spreewald and the city of Frankfurt (Oder), according to the state agriculture ministry.
Neighboring Saxony is the only other state where ASF-positive cases have so far been detected among wild boar. Its total stood at 61 as of March 12. This is five more than the previous week, reports the Saxony agriculture ministry. All infected cases have been found in the district of Görlitz.
So far, Germany has reported no cases of ASF among domestic pigs.
In Poland, the most recent cases of ASF among wild boar were released by the chief veterinary office on March 5.
South Africa reports ASF in 3 provinces
Latest official notifications from South Africa’s animal health authority to the World Organisation for Animal Health (OIE) outline four new ASF outbreaks.
In January, the virus was detected in a village herd of 45 pigs in Eastern Cape Province. One of the animals died at King Sabata Dalindyebo. This brings the province’s total to eight since April 2020.
Elsewhere in South Africa — also outside the nation’s ASF Control Zone — there were a further three outbreaks, according to the latest official report to the OIE.
Most recent of these was at a farm near Tlokwe city in North West Province. During the first week of March, 18 of the around 17,000 pigs at the premises died. In earlier outbreaks in Gauteng province — recently reported — ASF was detected at a farm with 106 pigs in West Rand district, and among 19 animals in a backyard herd in Sedibeng. These outbreaks began in late January and mid-February, respectively.
At each of the four outbreaks reported by South Africa, no information is given on the fate of any surviving pigs.
Starting in April 2019, this ASF series now includes 40 outbreaks. These involved a total of almost 36,000 pigs, including two large farms.
Last week, the OIE released global guidelines on compartmentalization for ASF.
View our continuing coverage of the global African swine fever situation.