Bovine tuberculosis and fasciolosis co-infection in cattle populations in Cameroon, Central Africa

The spatial epidemiology of bovine tuberculosis (bTB) and fasciolosis has been shown to have a negative association in the UK. Experimental studies show Fasciola hepatica co-infection down-regulates the cell-mediated (CM) immune response to Mycobacterium bovis infection in cattle. Hence fasciolosis co-infection could decrease the specificity of CM bTB diagnostics that are important in bTB surveillance and control programs globally. In Cameroon, where six million cattle are reared, bTB is uncontrolled and epidemiology minimally understood; despite the veterinary and public health importance of bTB. Fasciolosis is suspected to be endemic but little is known about the species of Fasciola present and its epidemiology. This study aimed to investigate the influence of fasciolosis co-infection on bTB diagnosis in Cameroonian cattle populations.

In 2012-13 an abattoir study and a stratified cross-sectional study were conducted in two study sites. An abattoir study sampled 2106 cattle and a cross-sectional study randomly sampled 1498 cattle from 100 herds. Individual cattle information was collected and 100 herdsmen were interviewed through a structure-questionnaire discussing husbandry practices. Various bTB diagnostics were conducted on cattle sampled including CM-tests and post mortem examinations (PME). Fasciolosis diagnostics included faecal egg counts (FEC), PME, a commercial antibody ELISA and development of a F. gigantica antibody ELISA.

F. gigantica parasites were solely identified by RAPD-PCR. Fasciolosis sero-prevalence ranged between 44.8-64.1% and bTB prevalence between 1.6-17.4%. Prevalence of both diseases varied within the study sites; shown using spatial and chi squared comparisons. Fasciolosis influence on bTB diagnosis was investigated using multivariable logistic regression analysis.