Flea borne Rickettsioses Associated with Rats in Palabuhanratu Port, Sukabumi, West Java, Indonesia

Abstract

Flea borne rickettsiosis remains unrecognized and often overlooked in many tropical regions, particularly in high-risk areas such as ports with dense human activity that potentially support the circulation of zoonotic pathogens. This study aimed to detect the presence of Rickettsia spp. in fleas infesting rats at Palabuhanratu Port, Sukabumi, West Java, Indonesia. Flea samples were collected from rats captured using single live traps baited with roasted coconut, set purposively in fish markets, offices, warehouses, and food processing facilities from July to October 2025. Identification of rats and fleas was based on morphological characteristics, and then the fleas were pooled based on flea and host species before DNA extraction. Detection of Rickettsia spp. was performed using the Polymerase Chain Reaction (PCR) method targeting the 17 kDa and gltA genes. A total of 131 rats were captured, consisting of 100 Rattus norvegicus (76.3%) and 31 Rattus tanezumi (23.7%), with flea infestation found in 29 rats (22.1%). The 69 fleas collected consisted of Xenopsylla cheopis (97.1%) and Ctenocephalides felis (2.1%), and were grouped into 29 pools. PCR results showed that 89.7% of the pool samples were positive for Rickettsia based on the 17 kDa gene and 65.5% based on the gltA gene. Phylogenetic analysis of both genes confirmed that the detected Rickettsia typhi belongs to the Typhus Group. These findings provide molecular evidence for the circulation of murine typhus in rat fleas in the port of Palabuhanratu, West Java, Indonesia and emphasize the importance of ongoing vector and reservoir surveillance to support public health risk control.