Anthelminthic treatment modifies cytokine profiles and improves the performance of tuberculin test in helminth-Mycobacterium bovis co-infection in cattle herds

While enormous efforts are directed at tackling the problems of human tuberculosis (TB) globally, the aspect of bovine TB (bTB) has received limited attention particularly in developing countries, where control policies are non-existent or inadequate. We compared the results of a single intradermal comparative cervical tuberculin test (SICCTT) with cytokine profiles before and after anti-helminthic treatment in cattle in their natural environment. Cattle were initially subjected to SICCTT and their helminth status assessed by coprological testing for Strongyle-type, Strongyloides sp., Toxocara vitulorum, Nematodirus sp., Paraphistomum cervi, Fasciola gigantica, Dicrocoelium dendriticum and Moniezia benedeni.; 60 days after, they were dewormed and the SICCTT was repeated with coprological testing; SICCTT-positives underwent post mortem examination and mycobacterial culture to confirm TB infection. Also, we measured the level of circulating type 1 (gamma interferon [IFN-{gamma}]), type 2 (interleukine-4 [IL-4]) and regulatory (transforming growth factor-beta [TGF-{beta}]) cytokines before and after anthelminthic therapy. Results revealed that cattle positive by SICCTT showed typical granulomatous lesions suggestive of TB which was confirmed by positive culture. The proportion of SICCTT positive cattle increased to about two folds following anthelminthic treatment. Cattle co-infected with helminth-bTB have significantly (p = 0.000) lower levels of IFN-{gamma} and higher levels of IL-4 and TGF-{beta}. Conversely, anthelminthic therapy led to significantly (p=0.000) elevated levels of IFN-{gamma}, concomitant (p =0.000) decreased levels of IL-4 and TGF-{beta}. Overall, we show that anthelminthic treatment can improve the rate of SICCTT positivity and reverse the modulation of cytokine responses in helminth-bTB co-infection.