Molecular detection of Rickettsia felis in fleas collected from domestic cats in Banjarnegara, Central Java, Indonesia

The cat flea is a main vector and reservoir of Rickettsia felis which is a flea-borne agent of spotted fever group rickettsiosis. The disease is considered a global threat to health but often underdiagnosed, likely due to their non-specific signs, symptoms, and limited access to diagnostics. There are limited reports of Rickettsia felis infection in cat fleas in Indonesia. This study aims to identify and characterize R. felis from cat fleas in Banjarnegara, Central Java, Indonesia. In total, 449 cat fleas (83 pools) were collected from 100 domestic cats in Banjarnegara and identified morphologically as Ctenocephalides felis and Xenopsylla cheopis (one flea). The flea samples were examined for Rickettsia spp. by conventional polymerase chain reaction (PCR) targeting the citrate synthase (gltA) gene, followed by sequencing to identify the species of Rickettsia. Ricketsia spp. was detected in 30 of the 83 flea pools (36.1%). Of the 30 positive Rickettsia sequencing, 23 samples were chosen for the phylogenetic tree reconstruction. BLAST analyses of the gltA sequences obtained from C. felis are similar to R. felis (>99%). The findings imply that Rickettsia felis is identified among cat fleas in Banjarnegara, providing the potential for human transmission.