Introduction: Babesiosis is caused by protozoa of the genus Babesia, with manifestations ranging from subclinical infection to life-threatening disease. Many Babesia species have been described in domestic and wild animals. This study aimed to investigate Babesia in unfed Rhipicephalus sanguineus sensu lato.
Material-methods: One hundred and forty DNA samples extracted from tick pools comprising 5403 unfed R. sanguineus s.l. (503 adults, 3100 nymphs, 1800 larvae) were screened for Babesia by 18S ribosomal RNA PCR (Polymerase Chain Reaction) and RLB (Reverse Line Blot) hybridization.
Result: Babesia infection was found in male, female, and nymph pools with an infection rate MLE (maximum likelihood estimate) of 1.98 [CI (Confidence Interval) 0.65-4.74)], 0.50 (CI 0.03-2.40), and 0.07 (CI 0.01-0.21), respectively. Babesia ovis was detected in one adult pool (MLE 0.47, CI 0.03-2.27) obtained from dogs and a nymph pool (MLE 0.03, CI 0.00-016) collected from the shelter grounds. Three adult female tick pools (MLE 1.44, CI 0.38-3.88) and one adult male pool (MLE 0.50, CI 0.03- 2.40), collected from dogs, hybridized to the catch-all and Babesia genus probes but did not show signals to other probes, suggesting the evidence of an unidentified Babesia. One nymph pool (MLE 0.03, CI 0.00-016) collected from the shelter grounds also hybridized to catch-all and Babesia genus probes but not species-specific probes. The maximum similarity (96.1-97%) observed was with Babesia sp. sable antelope, Babesia sp. Malbazar and Ludhiana isolates of dog origin, Babesia sp. of wild boar origin, Babesia sp. Kashi 2, and Babesia occultans of cattle origin.
Conclusion: The analysis of unfed R. sanguineus s.l. to be infected with B. ovis and a novel species of Babesia. The latter isolate is suggested to be a new species based on its 18S rRNA sequences, and further studies in the vertebrate host, especially dogs, would help to determine its epizootiological significance.
