NEMATODE INFECTION EFFECTS ON IMMUNOPATHOLOGICAL RESPONSE TO VACCINE AND MYCOPLASMA CAPRICOLUM CAPRIPNEUMONIAE ANTIGENS IN GOATS

Abstract

Contagious Caprine Pleuropneumonia (CCPP), caused by Mycoplasma capricolum capripneumoniae (Mccp), is a highly contagious disease of goats with high morbidity and mortality in naïve goats and a major threat to food security. The objective of this study was to investigate the impact of mixed nematode infection on immune responses to vaccine and native Mccp antigens and the resultant pathology in goats. To investigate the humoural response to vaccine antigen, 40 goats aged 9 – 12 months were randomly allocated to four groups of ten each. Group A were orally inoculated with infective stages of nematodes followed by immunization with inactivated Mccp vaccine after 3 weeks. Group B were not inoculated with nematodes but immunized as Group A. Group C were inoculated with infective stages of nematodes but not vaccinated as in A. Group D was neither inoculated nor vaccinated. To investigate pathology in response to native Mccp antigens 24 goats divided into four groups of six were used. Group E1 without and E2 with detectable nematode were inoculated intratracheally with Mccp organisms. F1 without and F2 with detectable nematode were used for contact transmission investigation were brought in contact with inoculates on the 7th day post inoculation. Clinical observations and records were done daily at 8.30 am, blood for sera analysis was collected weekly, while pathological data was collected at post-mortem. Analysis of Variance and Tukey Honest Significant Difference, a post hoc test, multiple comparisons of means were performed using R statistical packages (Rx64 3.2.4 revised). The results showed that immune response to Mycoplasma vaccine antigens in nematode infected group (A) was significantly lower than that in vaccinated non-nematode infected (B) group (p<0.05). Red and gray lung consolidations were significantly different statistically (p< 0.05) thus corresponding to the observed clinical signs, fibrin deposition along with pleural effusions in nematode infected groups. There was a high morbidity in group E2 (4/6) compared to E1 (1/6) that necessitated euthanasia for welfare reasons. Fibrous adhesion, a sign of chronic disease was more pronounced in none nematode infected groups though not statistically significant (p> 0.05). Evidence from this study indicates that worm infection impacts negatively on immune response to Mccp infection, vaccine antigens and the resultant pathological picture. Thus I recommend that deworming exercise should be carried out before planned vaccinations are carried out.