Seroprevalence of Contagious Bovine Pleuropneumonia in Eastern Sudan with Development of a Rapid Test for Serodiagnosis

Abstract

Contagious Bovine Pleuropneumonia (CBPP) is one of the serious threats to the livestock in Sudan. For effective control of CBPP, early diagnosis is the cornerstone. Culture method is considered laborious, expensive and time consuming. The aim of this study was to estimate the seroprevalence and geographical distribution of Contagious Bovine Pleuropneumonia (CBPP) in Eastern states of Sudan, and to identify the highly risk areas within its localities. The objective also included isolation and full identification of new strain of Mycoplasma mycoides subsp mycoides using conventional, molecular and bioinformatic techniques. Development of stained antigen for sero- diagnosis of CBPP, from local strain besides T1/44 reference strain was one of the main targets of this study. A total of 1960 serum samples were collected randomly from cattle in Al Gedaref, Red Sea and Kassala states. The samples were tested using competitive ELISA (c. ELISA). The highest seroprevalence was observed in Al Gedaref state (12%), followed by Kassala (6.9%) and Red Sea state (4.1%). In Al Gedaref state; Al Galabat Eastern and Al gurisha localities had scored the highest seroprevalence (17.1%). In Kassala state the highest seroprevalence was observed in Naher Atbara locality (17.1%). In Red Sea state the highest seroprevalence was observed in Sawakin locality (11.4%). Mycoplasma mycoides subsp mycoides (Mmm) strain was isolated from clinically diseased animal and characterized using conventional and molecular techniques. Using bioinformatics tools the isolated RH strain was confirmed to be Mmm and 100% similar to certain strains in gene-bank (PG1and Vmm). Two types of stained antigen were developed for using in sero- diagnosis of CBPP. First antigen was produced from T1/44 reference strain (SAT1) and the second one was produced from (RH) local strain (SAT2). The antigens were evaluated using standard positive and negative reference serums. Competitive ELISA -as a golden test- was used to estimate their sensitivity and specificity beside Latex agglutination test (LAT). The antigens (SAT1 and SAT2) were highly sensitive and specific (100%) when tested against 15 positive serum samples from infected herd (confirmed by isolation of Mmm). Statistical analysis using Pear-son Chi-square test and Kappa test revealed that the sensitivity of the developed stained antigen (compared with c.ELISA) from T1/44 strain (SAT1) was 100% in comparison of 92% and 95% of SAT2 (RH local strain) and LAT, respectively. The specificity of the developed SAT2 antigen was (70%) when compared with c. ELISA, which was higher than SAT1 (31%) and LAT (59.6%). From these results it could be concluded that SAT2 -which was produced from local strain proved to be more specific and highly sensitive with low cost and easy application in the field.