#17,710
Today the Finnish Food Safety Authority (Ruokavirasto) issued the first results of their enhanced survey of all mink farms in the country for H5N1 which was announced last August and officially got underway in September.
Since mid-summer we've seen 27 fur farms infected with H5N1 in Finland, and while most involved foxes and raccoons, 3 of those farms also raised mink.
Mink are particularly susceptible to COVID and Influenza A infection, raising concerns that they could act as a mixing vessel (see graphic above), possibly leading to the creation of a more dangerous virus. This concern was well addressed a couple of months ago by two well known UK virologists in an opinion piece published in the Journal PNAS.
Mink farming poses risks for future viral pandemics
Thomas P. Peacock and Wendy S. Barclay
July 19, 2023
120 (30) e2303408120
https://doi.org/10.1073/pnas.2303408120
Although the translation is somewhat cryptic, it appears two additional mink farms ( in Vöyri and Pedersöre, in Ostrobothnia) have been found infected with avian flu (n=5). Only about 1/3rd of Finland's mink farms have been tested thus far, and there are several hundred additional fur farms that raise fox and raccoon that will need testing as well.
Surveys of mink farms have so far detected avian influenza on two fur farms
6 October 2023
In the first results of the avian influenza survey of mink farms, avian influenza has been detected in two farms. In the studies, avian influenza was found in mink farms located in the municipalities of Vöyri and Pedersöre, in Ostrobothnia. So far, the Finnish Food Authority's laboratory studies have analysed samples from 35 mink farms included in the survey.
Last summer, avian influenza infections in fur animals were detected in Ostrobothnian farms, which have since been found in a total of 27 farms in four regions. In order to map the avian influenza situation, the Finnish Food Authority launched monitoring of all fur farms in mid-September. In the first phase of the survey, samples from farms with mink are examined, because avian influenza infections in mink pose a greater health risk to human health than avian influenza infections in other fur animals.
So far, samples have been taken from 53 fur farms. The Regional State Administrative Agency for Western and Inland Finland is responsible for organising sampling and coordinating the mapping for the whole of Finland. The majority of fur animal farms in Finland are located in the area of the Regional State Administrative Agency for Western and Inland Finland. There are 114 fur farms with minks in Finland. Five of these farms have been diagnosed with avian influenza prior to the survey.
At the beginning of the survey, blood samples were taken from the farms for antibody testing and dead animals for virus detection (PCR test). From the beginning of week 40, only blood samples were taken in the survey. The purpose of the change was to speed up the progress of the survey so that potentially infected mink farms can be screened out before the human influenza season begins.
Antibodies caused by influenza A virus in fur animals are first examined by the ELISA method. Antibody-positive samples are confirmed by the HI method (hemagglutination inhibition). The method studies the binding of antibodies in the sample to the HA protein of the influenza A virus isolated from fur farms. The test accurately detects antibodies to the H5 virus.
The Finnish Food Authority will order animals to be euthanized from fur farms where antibodies against H5 avian influenza are detected in samples. The first phase of the avian influenza survey concerning mink farms is expected to be completed by the end of October, after which the monitoring and sampling of fox and raccoon dog farms will begin.
Given the number of fur farms, and the time it takes to run these tests, it will likely be early next year before all of these farms can be tested.
With migratory birds returning from their summer roosting places, the risks of new outbreaks are only likely to increase in the months ahead.Of course, even farms that get a clean bill of health today are still at risk of future infection.
