RESUMO
Bovine babesiosis represents a serious threat to the cattle industry in the tropics and subtropics. Although several Babesia species infect cattle, only B. bovis, B. bigemina and B. divergens are known to cause clinical babesiosis. However, our recent study demonstrated that the newly discovered Babesia sp. Mymensingh might be a virulent species capable of causing clinical babesiosis in cattle. The objective of this study was to determine the host range and geographical distribution of Babesia sp. Mymensingh on a global scale. A total of 2,860 archived DNA samples from 2,263 cattle in Sri Lanka (n = 672), the Philippines (n = 408), Vietnam (n = 460), Uganda (n = 409), Brazil (n = 164) and Argentina (n = 150); 419 buffalo in Sri Lanka (n = 327) and Vietnam (n = 92); and 127 goats and 51 sheep in Vietnam were screened using a Babesia sp. Mymensingh-specific PCR assay. Babesia sp. Mymensingh infection was detected in cattle, buffalo, sheep and goats. Cattle of all countries surveyed in this study except Brazil were found to be infected with Babesia sp. Mymensingh. The highest positive rates were recorded in cattle from the Philippines (11.3%) and Vietnam (9.6%), followed by Argentina (4.7%), Sri Lanka (1.5%) and Uganda (1.0%). Buffalo were found to be infected with this parasite in Sri Lanka (1.2%) and Vietnam (10.9%). Unexpectedly, Babesia sp. Mymensingh was also detected in sheep (2.0%) and goats (1.3%) from Vietnam. These findings were confirmed by PCR amplicon sequencing. In conclusion, our present findings indicate that Babesia sp. Mymensingh, which infects cattle, buffalo, sheep and goats, is endemic in Asia, Africa and South America.
RESUMO
Hammondia heydorni is a coccidian parasite with an obligatory two host life cycle, with dogs and foxes as definitive hosts, and a number of intermediate hosts, including goats. While infection by this parasite seems to be unassociated with any clinical signs, infection by the closely related parasites Neospora caninum and Toxoplasma gondii can result in abortion, stillbirths and low yielding in caprine herds. The aim of this work was to investigate the frequency of goats infected with H. heydorni using a nested PCR, specific to Toxoplasmatinae internal transcribed spacer 1 (ITS1) of the rDNA, followed by sequencing of the purified PCR fragments. The same molecular techniques were used to determine the frequencies of N. caninum and T. gondii-infected animals. A total frequency of 13.72% (14/102) was obtained for Toxoplasmatinae DNA in goat tissues. After sequencing the PCR products from all positive tissues, a frequency of 3.92% (4/102), 1.96% (2/102) and 7.84% (8/102) were obtained for H. heydorni, N. caninum and T. gondii, respectively. All sequences shared 98-100% identity with sequences from other strains of these coccidia present in GenBank. To the authors' knowledge, this is the first report of H. heydorni DNA in tissues from naturally infected intermediate hosts.
