Clinical and laboratory diagnosis of contagious caprine pleuropneumonia in Qassim region, Saudi Arabia: a comparative study

ABSTRACT

Diagnosis of contagious caprine pleuropneumonia (CCPP) in Saudi Arabia mainlydepends on clinical signs and post-mortem findings, in addition to limited usage of latexagglutination test (LAT). In this study, a PCR method specific for detection of Mycoplasmacapricolum subspecies capripneumoniae (Mccp) was used as a direct confirmatory methodand to compare it with clinical signs, necropsy lesions and LAT. During the 2016-2017 year,samples of serum, pleural fluid, lung tissue and nasal swab were collected from 40 goats withclinical signs of CCPP, which were selected from goats brought to the veterinary clinic ofQassim University from 18 goat herds and nine localities. Epidemiological data revealed34.1%, 27.8% and 81.6% morbidity, mortality and case fatality rates, respectively. At necropsy,31 of 40 goats (77.5%) were found with lesions matching those of CCPP. Molecular findingssupported the suitability and applicability of PCR as a reliable method to diagnose andconfirm CCPP directly from clinical samples. The disease was confirmed by PCR in 35 goatsout of 40 (87.5%), 15 herds out of 18 (83.3%) and in all localities. Sera of 32 goats (80%) werefound positive by LAT. Four of the five goats and two of the three herds negative by PCR werealso negative by LAT and necropsy examination. Therefore, PCR sensitivity was considered97.2% (35/36). Compared to the claimed high specificity and sensitivity of the used PCRmethod, diagnosis of CCPP based on clinical signs was found less specific and necropsyexamination and LAT were less sensitive. It was concluded that molecular detection of Mccpdirectly in clinical samples should routinely be used to confirm diagnosis of CCPP in theregion of study, prevent economic impact of wrong diagnosis and to hasten control process.