Strep Zoo Outbreak Demonstrates Value of African Swine Fever Rule-Out Testing

An outbreak of Streptococcus equii zooepidemicus reported in the third quarter of 2022 in western Canada has demonstrated the value of African Swine Fever rule-out testing.

The Canada West Swine Health Intelligence Network's Swine Health Surveillance Report for the third quarter of 2022 references a Strep zoo outbreak on a five thousand sow operation where 69 sows died over seven days.

CWSHIN Manager Dr. Jette Christensen says, because pigs on the farm responded well to antibiotics, the outbreak was not considered an ASF suspect case but instead samples were submitted for ASF rule out testing.

Clip-Dr. Jette Christensen-Canada West Swine Health Intelligence Network:

It's a very rare disease.It is very very severe.It causes sudden deaths in sows.The additional problem is that the signs are so severe that they can mimic African Swine Fever, so the question was is this a suspect African Swine Fever case or is it something else.

If it's an African Swine Fever suspect case, such and case needs to be reported to CFIA immediately and they will do a full investigation but if it's not a suspect case, the other option is to make a rule-out test.

Because this case was likely a bacteria as it responded to antibiotic treatments they could say that this is not a suspect case but it should be tested for African Swine Fever just to be on the safe side so they sent it for rule-out testing.

It turned out, with the laboratory testing, it was not African Swine Fever but it was Streptococcus zooepidemicus.

Dr. Christensen says, when confronted with symptoms that mimic ASF such as sudden death, internal bleeding and discoloring of the skin, call your herd practitioner who will investigate, submit samples and request an ASF rule-out test.