Molecular evidence of spotted fever group rickettsiae and Anaplasmataceae from ticks and stray dogs in Bangladesh

Emerging tick-borne diseases (TBDs) are important foci for human and animal health worldwide. However, these diseases are sometimes over looked, especially in countries with limited resources to perform molecular-based surveys. The aim of this study was to detect and characterize spotted fever group (SFG) rickettsiae and Anaplasmataceae in Bangladesh, which are important tick-borne pathogens for humans and animals worldwide. A total of 50 canine blood samples, 15 ticks collected from dogs, and 154 ticks collected from cattle were screened for the presence of SFG rickettsiae and Anaplasmataceae using molecular-based methods such as PCR and real-time PCR. The sequence analysis of the amplified products detected two different genotypes of SFG rickettsiae in ticks from cattle. The genotype detected in Rhipicephalus microplus was closely related to Rickettsia monacensis, while the genotype detected in Haemaphysalis bispinosa was closely related to Rickettsia sp. found in Korea and Japan. Anaplasma bovis was detected in canine blood and ticks (Rhipicephalus sanguineus and H. bispinosa). Unexpectedly, the partial genome sequence of Wolbachia sp., presumably associated with the nematode Dirofilaria immitis, was identified in canine blood. The present study provides the first molecular evidence of SFG rickettsiae and A. bovis in Bangladesh, indicating the possible emergence of previously unrecognized TBDs in this country.