Trans-species transmission of Brucellae among ruminants hampering brucellosis control efforts in Egypt

Aims This study aimed to identify the genotypic fingerprinting of B. melitensis biovar 3 isolates from ruminants in Kafr El-Sheikh, Egypt, to compare with other peers globally, and to highlight the epidemiology and potential causes of brucellosis control failure.Methods and Results A multilocus variable-number tandem-repeat analysis (MLVA 16) was carried out on 41 B. 29 melitensis bv3 isolates, 31 from the preferential hosts (28 sheep and three goats), and ten from atypical hosts (nine cattle and one buffalo), identified by bacteriological and molecular techniques. MLVA-16 analysis revealed 19 genotypes with nine as singletons. The most prevalent genotypes were M3_K.E (3,5,3,13,1,1,3,3,7,43,8,7,6,7,5,3), M13_K.E (3,5,3,13,1,1,3,3,7,43,8,5,8,7,7,3), and M5_K.E (3,5,3,13,1,1,3,3,7,43,8,4,8,7,11,3) circulating between different animal species. The B. melitensis isolation from aborted cows in farms that had never reared small ruminants indicates the likelihood of cow to cow B. melitensis transmission. Different genotypes of B. melitensis could be isolated from the same animal. The local geographic distribution of genotypes showed a very close genetic relatedness with genotypes reported outside the study area. Worldwide, our genotypes were mostly related to the Western Mediterranean lineage and less likely to the Americas clonal lineage. Conclusion There is a high genetic similarity of B. melitensis bv3 genotypes among different ruminant species and the same animal could be infected with different genotypes. There is a high probability of spreading of B. melitensis among atypical hosts in the absence of the original