Although the O field strain of foot-and-mouth disease (FMD) has never officially been recorded in South Africa, laboratory analysis has confirmed the presence of inactivated O strain in the shipment of smuggled vaccines intercepted by authorities at Polokwane Airport in late November.
By Lloyd Phillips, senior journalist at African Farming and Landbouweekblad
An informed source in the country’s animal health industry who spoke on condition of anonymity, says the analysis was conducted by the Agricultural Research Council’s Transboundary Animal Diseases facility in Pretoria.
African Farming has previously reported that South Africa’s stocks of legal registered vaccine against the country’s SAT1, SAT2 and SAT3 strains of foot-and-mouth disease became severely limited and eventually totally depleted in recent months. Imports of new stock are only expected to resume from the end of January at the earliest.
In the interim, some farmers desperate to protect their herds from FMD that has run rampant in the absence of registered vaccine, reportedly resorted to having vaccines that are not registered for use in South Africa and are, therefore, illegal, smuggled into the country.
Also read: FMD | Potentially dangerous vaccines still being smuggled in
Dr Mark Chimes, a veterinary adviser and programme manager for animal health and welfare at Milk South Africa, previously told African Farming the origins of these smuggled vaccines include Kenya and Zambia. At that time, he expressed concerns that these vaccines may contain the live A and/or O strains of FMD that officially do not exist in South Africa. Administering one or both strains to animals in South Africa might potentially result in them becoming field strains here and, therefore, an added threat.
It is also known that Kenya manufactures FMD vaccine for use in Zambia.
Chimes said these vaccines smuggled in from Zambia only contain the SAT1 and SAT2 strains of FMD that already exist in South Africa.
Confusing the big picture of foot-and-mouth disease
The anonymous source says the confirmation of the inactivated O strain in the smuggled shipment of FMD vaccines intercepted at Polokwane Airport in Limpopo, does not automatically mean the live O strain of the virus is now circulating in South Africa.
Chimes confirms: “It merely means animals vaccinated with this vaccine will have antibodies against the O strain and possibly against the A strain if this latter strain is also in some smuggled vaccines. However, this will all confuse the picture of foot-and-mouth disease in South Africa.”
He explains that South Africa’s livestock that are officially vaccinated against FMD are registered as being vaccinated.
Neither the Botswana Vaccine Institute’s vaccine authorised for use in South Africa, nor the vaccines smuggled in from Kenya and Zambia, are of the DIVA- (Differentiating Infected from Vaccinated Animals) type. Therefore, the blood tests currently used to identify new outbreaks of this disease in South Africa cannot differentiate between the antibodies against foot-and-mouth disease that are caused by reactions to these non-DIVA vaccines and those antibodies caused by infection by actual field strains of this disease.
During such testing, South Africa’s animal health authorities use the register of vaccinated livestock to help them identify unvaccinated animals that have antibodies against foot-and-mouth disease and are, therefore, likely infected with a field strain.
Livestock vaccinated with smuggled vaccine will not be on the register. So, if they are tested for FMD for any reason, the antibodies in their blood will be assumed to be due to an active infection of this disease.
“If they were vaccinated with the vaccine that originated from Kenya, they might test positive for the O strain and maybe the A strain. This may well lead animal health authorities to think we now have the live O and/or A strains circulating in South Africa.
“The most accurate way to confirm whether an animal is infected with a field strain of FMD is to use a PCR (polymerase chain reaction) test or a viral culture to find the actual virus in samples. Until the actual O strain and/or A strain of the virus is isolated in such a sample, we can accept that we do not have the live O and/or A strains circulating in South Africa.”
Commander Jan Nel, biosecurity officer at the Red Meat Industry Services (RMIS), says the State Security Agency’s investigations into FMD vaccines smuggled into South Africa are still at a very sensitive stage.
“I can’t confirm if the smuggling is still continuing, but we’re on high alert for anything”.
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