The impact of helminth infections on the effectiveness of brucellosis immunoprophylaxis in cattle

Abstract

Background and Aim. Brucellosis remains one of the most significant bacterial zoonoses affecting livestock productivity and public health worldwide. Vaccination is the cornerstone of bovine brucellosis control; however, its efficacy may be reduced by factors that affect the host immune response, including parasitic infections. Helminths are known to modulate immune and may suppress vaccine induced antibody production. This study aimed to evaluate the effect of helminth infestation on antibody production following vaccination with Brucella abortus strain 82 and to assess the impact of prior anthelmintic treatment.
Materials and Methods. A total of 20 cattle were divided into two groups (n = 10 each). Helminth infections were confirmed in all animals using coproscopic and larvoscopic methods, including the Fulleborn flotation technique. The experimental group received anthelmintic treatment (Monizen forte, 1 µL/20 kg body weight, orally) before vaccination, whereas the control group was vaccinated without prior deworming. All animals were immunized with B. abortus strain 82 (5 µL, subcutaneously). Blood samples were collected 26 days after vaccination, and antibody responses were assessed using the indirect hemagglutination assay, agglutination test, and thecomplement fixation test.
Results. Parasitological analysis revealed mixed helminth infections (Dictyocaulus spp., strongylates, Nematodirus spp., and Moniezia spp.) in allanimals. Anthelmintic treatment demonstrated high efficacy, resulting in the complete elimination of strongylates and monieziosis. Serological results showed significantly stronger and more consistent antibody responses in the treated group compared with untreated controls, which exhibited lower titers and heterogeneous reactions.
Conclusion. Helminth infestation adversely affects post vaccination humoral immunity against brucellosis in cattle. Pre-vaccination deworming enhances antibody production and may improve the effectiveness of brucellosis control programs.