Combination with Annual Deworming Treatments Does Not Enhance the Effects of PCV2 Vaccination on the Development of TB in Wild Boar Populations

Simple Summary Tuberculosis (TB) is a highly prevalent disease in wild boar from Southwestern Spain, which in turn plays a key role in the maintenance of TB prevalence in bovine and other sympatric species. The severity of TB lesions in wild boar may be triggered by coinfections with pathogens like Porcine Circovirus type 2 (PCV2) or Metastrongylus spp. In fact, measures focused on the control of these pathogens (such as vaccination against PCV2 and reiterative ivermectin treatments) have proven to be effective in reducing the severity of TB in wild boar. This study aimed to assess whether a combination of deworming treatments and vaccination against PCV2 improves TB development in wild boar. The results confirmed that PCV2-vaccinated animals showed lower probabilities of suffering severe TB lesions. However, the obtained data suggest that annual deworming is not sufficient to produce a long-term parasitological load reduction that is able to influence the development of TB in wild boar, nor does it improve the effect of PCV2 vaccination on this disease. The combination of both treatments did not improve the results compared to PVC2 vaccination alone.Abstract Vaccination against PCV2 has been proven to be an effective measure to reduce the severity of TB in wild boar. The combination of this measure with strategies focused on treating other key concomitant pathogens, such as nematodes, could be a useful strategy. This study assesses whether a combination of deworming treatments and PCV2 vaccination may reduce the prevalence and severity of TB in wild boar. The study was conducted on five game estates in mid-western Spain where four groups of wild boar were produced: control, vaccinated, dewormed and vaccinated-dewormed. Wild boars from all groups were hunted between 2017 and 2020, and all of them received a TB diagnosis based on pathological and microbiological tests. Generalised linear models were used to explore the effect of deworming and PCV2 vaccination on TB prevalence and severity. PCV2-vaccinated animals showed lower probabilities of suffering severe TB lesions. However, no differences regarding TB severity were found between dewormed and non-dewormed wild boar. PCV2 vaccination reduces TB severity in wild boar. However, annual deworming does not produce a long-term parasitological reduction that can influence the development of TB in wild boar, nor does it improve the effect of PCV2 vaccination on TB.