By Dr. Rob Taylor, SAPPO representative on the Joint Operations Centre CSF in the Eastern Cape. The article was written on behalf of the Pig Vet Society.
Wild boars in Europe are susceptible to CSF. We should demonstrate that our bushpigs are free from the disease, or are not susceptible, so as to be sure there is no reservoir of infection. There is currently little information on the role wild pigs (warthog, bushpigs [Potamochoerus larvatus] and feral pigs) play in harbouring or spreading the disease. Susceptibility tests on bushpigs are being carried out by the Onderstepoort Veterinary Institute.Veterinary staff in the Eastern Cape will collect samples from wild pigs in the province, especially from those areas where the disease has occurred. The practice of allowing domestic pigs to run free in these areas, would have given bushpigs ample opportunity to come into contact with CSF infected domestic pigs. The collection of samples will be approached from two angles: In the western part of the province, hunting of bushpig is well established. Hunt clubs and the farming community have been approached to assist in the collection of samples when bushpig are hunted.
In the eastern half of the province, much of which is communal grazing land, it is hoped to trap bushpigs. Trapped pigs would then be processed as in the case of culled domestic pigs with the collection of the required tissue and blood samples. A protocol has been developed for the correct procedures to be followed for the collection and transport (on ice) of specimens to the laboratory.Each operation poses its own challenges: Hunters are reluctant to interrupt the normal process to obtain samples in the correct and sterile manner.
Some farmers are concerned that if CSF positive samples are obtained from bushpig originating from their farms, further state veterinary interest would hamper their commercial hunting operations and compromise their livelihood. This is unfortunate as there would be little interference other than to try and obtain further samples for testing. The movement of bushpig meat and trophies is already controlled in the Eastern Cape Province.
Bushpigs are known to be very wily creatures and are difficult to capture. Len Potgieter, Chief Animal Health Technician of the Animal Disease Surveillance Unit, has a sound knowledge of this species, as he has hunted them for many years. He has developed a cage (boma) trap big enough to contain a sounder (± five to twelve) of bushpigs.
The trap, made of mesh and measuring 2, 4 x 2, 4 x 0, 9 m, has been built. The gate and trigger mechanism is similar to that of the traps used for jackal in the area. Maize will be used to bait the trap. It is expected that the bushpig will have to be lured to the trap and fed there for some time in order for them to get used to it; before the trap can be set to catch what will hopefully be a sounder at a time.
Further enticements, such as the urine of domestic sows in oestrus and recordings of the vocalising of boars may be used as well. Animal welfare has been involved in the development of the system. Traps will be checked twice daily by a trained operator. Any captured bushpigs will be processed immediately. Should any other species of wild or domestic animal be caught in the trap, they will be released according to a safe code of conduct devised in conjunction with all stake holders.
Before the traps (five in all) are placed, discussions with the local headmen and councillors will be held. This is necessary to obtain the support of the local community for the exercise. In this way, the local knowledge and expertise for the optimum placing of the traps, can also be used.Trapped pigs will be tranquilised immediately, then stunned with the captive bolt, before the specimens are collected and the carcasses buried.
The question of compensation now arises. Should the community be allowed to eat the pig? This is not possible, because it would contain tranquilliser residues. Should the local village then be compensated according to the tariff of compensation for culled domestic pigs?
On the other hand, who owns the pig if it is wild and is on government land? Therefore, for the furtherance of the disease control campaign, there should be no compensation due at all.These are some of the aspects that have to be resolved satisfactorily in order to ensure the success of the campaign.
The outcome of the trials at Onderstepoort Veterinary Institute and the results of the serological survey of the bushpigs of the Eastern Cape remain critical to the potential lifting of restrictions for Classical Swine Fever outbreak in the Eastern Cape.
In all, it is important to ensure that a CSF negative (free) status can be achieved as soon as possible and the OIE convinced that there is no reservoir remaining in the wild animals.
Buffalo and other wild ungulates are reservoirs of the FMD virus in the vicinity of the KNP and this necessitates a lot of state surveillance to allow beef exports. The country does not need another similar disease to hamper trade.