Detection, molecular epidemiology, and mapping of Anthrax outbreaks in Jordan, 2018-2021

Background Anthrax remains a significant public and veterinary health concern in Jordan and the broader Middle East. Methods Between 2018 and 2021, we investigated 31 suspected outbreaks by collecting 1,094 samples from suspected anthrax-infected carcasses, the surrounding non-vaccinated asymptomatic livestock, and environmental surfaces. Of these, 956 samples were tested using qPCR for the chromosomal marker ba 177 and the plasmid marker pag . Results A total of 349 samples (36%) were ba 177-positive, and among these, 92% also carried pag , indicating the presence of fully virulent B. anthracis strains. In parallel, 141 blood serum samples from asymptomatic animals were tested using ELISA for antibodies against protective antigen (PA), with 53% testing seropositive. A subset of 93 animals tested by both qPCR and ELISA showed overlapping results, revealing a proportion of animals with both molecular and serologic evidence of exposure. These findings indicate that a significant number of apparently healthy animals had been exposed to B. anthracis , suggesting their possible role as carriers within affected herds. Further molecular typing using canSNP analysis identified two isolates belonging to the C.Br.A1005 lineage, a clade distinct from those previously reported in the region. This genetic insight points to the potential circulation of multiple B. anthracis lineages in Jordan and highlights the value of combining molecular and serological tools for anthrax surveillance and control. Conclusion By pinpointing the locations of Bacillus anthracis on farms, our findings will contribute to more effective control of anthrax and limit the spread of the pathogen both within agricultural settings and in surrounding natural environments. This information will ultimately enhance overall biosecurity measures.