ABSTRACT
In tropical countries, clinical bovine babesiosis is a tick-borne disease primarily caused by Babesia bovis and Babesia bigemina. Here, we investigated 11 cattle with presumptive diagnosis of clinical babesiosis in Boyolali district, Central Java, Indonesia. The majority of the animals were anemic, as evidenced by lower hematocrit, hemoglobin concentration, and red blood cell counts than the normal ranges. Blood DNA was analyzed by a PCR assay targeting the 18S rRNA-ITS region of babesial origin, and the results confirmed that the cattle were infected with Babesia species. The sequencing and phylogenetic analyses demonstrated that the animals were infected with Babesia naoakii. This is the first report of B. naoakii in Indonesia and of B. naoakii-induced clinical bovine babesiosis outside of Sri Lanka. B. naoakii causes a persistent infection, as indicated by positive PCR results for serial blood samples of the circulatory system taken two weeks after treatment. Consequently, subclinical or newly recovered cattle may serve as potential intermediate hosts and infect ticks as definitive hosts to complete the life cycle. To identify potential tick vectors, we collected ticks from cattle, including 11 animals with clinical babesiosis. Based on the morphology and the mitochondrial cytochrome c oxidase subunit 1 (COX1) of collected ticks, we found that all of the collected ticks were Haemaphysalis bispinosa, identifying this tick species as a potential vector of B. naoakii in Indonesia. In this study, the evaluation of local farmers' awareness and practices regarding tick-borne diseases is presented, as disease prevention is also reliant on the implementation of strategies for vector control. Since livestock activities in Java represent the country's busiest animal trade, thereby the spread of disease to other regions is possible through anthropogenic factors. In conclusion, B. naoakii is a causative pathogen of clinical bovine babesiosis autochthonously occurred in this report and further research on B. naoakii-infection is required in other regions of the country. The prompt treatment of the disease seemed crucial for animal survival, which implies the necessity of early diagnosis and a sensitive detection method.
