Studies on the Effectiveness of Treatment and on Carrier Status of Contagious Caprine Pleuropneumonia in Experimentally Infected Goats

Abstract

In this study, a randomized clinical trial was carried out in twenty-nine goats after experimental infection. Three experimental groups each with eight goats and one control group with five goats were used in this study. Antimycoplasmal drugs i.e. tetracycline, tylosin and streptomycin were assessed on the basis of clinical cure, pathological lesions and carrier status of Mycoplasma capripneumoniae infection for the three experimental groups. On day 60 post-infection, the surviving goats were slaughtered and pathological lesions were assessed. Detection of Mycoplasma capripneumoniae in the slaughtered goats was based on isolation and on a combined polymerase chain reaction/ restriction enzyme analysis (PCR/ REA). A simple scoring index based on drug efficacy, pathological lesions, and isolation, availability and relative costs of treatment was constructed. All eight goats treated with streptomycin recovered and the risk ratio of recovery was 2.5 with 60% drug efficacy (p value=0.035) and all had pleuritic adhesions while only 37.5% had pneumonic lesions. In the tetracycline treated group only one of the eight goats did not recover, therefore, the risk ratio of recovery was 2.2 with 54.3% efficacy (p=0.217). In this group pneumonic and pleuritic lesions were observed in only one goat. Goats treated with tylosin had 62.5% (5/8) recovery percentage and the risk ratio of recovery was 1.6 with 36% efficacy (p=0.592).  All goats showed pneumonic lesions and 80% had pleuritic adhesions. Isolations of Mycoplasma capripneumoniae was observed in the untreated goats, tetracycline and tylosin treated groups. The PCR/REA test detected Mycoplasma capripneumoniae in spontaneously recovered goats and animals from each treatment group. In view of the findings of this study it can be concluded that treatment with tetracyclines and tylosin does not seem to eliminate carrier status and carrier status in goats treated with streptomycin is doubtful based on the inability to isolate Mycoplasma capripneumoniae. This study demonstrates that streptomycin was the best drug followed by tetracycline and tylosin