The outbreak of migratory goat’s brucellosis in the Swat ecosystem of Khyber Pakhtunkhwa

Brucellosis is a major threat to public health especially in developing countries including Pakistan. This study reveals the characterisation of Brucella species affecting humans and goats in the Swat region of Khyber Pakhtunkhwa, Pakistan. Blood samples were collected from shepherds and goats and analysed by Rose Bengal precipitation test (RBPT), standard plate agglutination test (SPAT), polymerase chain reaction (PCR) and Sanger sequencing of 16S rRNA gene. The findings of the study indicated 24% (36/150) and 11.3% (17/150) positivity for Brucella abortus and Brucella melitensis, respectively, in human samples. In samples of goats, 26.66% (40/150) were positive for B. abortus and 16.66% (25/150) samples were positive B. melitensis by SPAT. The species-specific PCR confirmed B. abortus in 24% (36/150) of human samples and 26.66% (17/150) of goat samples by targeting the IS711 locus. The remaining seropositive samples were confirmed as B. melitensis using IS711 M species-specific primer. The sequences of the amplified fragments of the 16S rRNA gene were blasted, and phylogenetic analysis revealed that Brucella species circulating in the Swat district were closely related to B. melitensis and B. abortus reported from India, China, Philippines, and the United States (US) showing the existence of the possible epidemiological linkage among the Brucella species. This study concluded that there was a higher prevalence of B. abortus (26.6%) in humans and goats compared to B. melitensis (16.6%). These results revealed that the Brucella species were circulating in both humans and goats in the study areas. The findings of the study concluded that B. abortus and B. melitensis were circulating in goats and shepherds with a higher prevalence of B. abortus than B. melitensis. Furthermore, the Brucella species identified in Swat were phylogenetically related to the Brucella species reported from India, China, Philippines and the US. Contribution: The proposed study covers the scope of the journal. The species of the genus Brucella affect both animals and shepherds. This study investigates the seroprevalence of brucellosis in shepherds and goats in different geographical areas in the Swat district. The phylogenetic analysis of the Brucella spp. identified in Swat showed close relationships to the Brucella species reported in India, China, Philippines and the US, which shows the possible epidemiological linkages between the Brucella spp.