AUTHOR=Wu Jiajun , Cao Jie , Zhou Yongzhi , Zhang Houshuang , Gong Haiyan , Zhou Jinlin 

TITLE=Evaluation on Infectivity of Babesia microti to Domestic Animals and Ticks Outside the Ixodes Genus

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01915

DOI=10.3389/fmicb.2017.01915

ISSN=1664-302X

ABSTRACT=<p>Babesiosis caused by <italic>Babesia microti</italic> parasite is an emerging tick borne zoonotic disease that was confirmed recently in China. To understand the epidemiology characteristics of this emerging disease, infectivity of <italic>B. microti</italic> to domestic animals and ticks outside the genus Ixodes was evaluated in this study. Different domestic animals, chick, pig, goat, dog and the reference host rat were experimentally inoculated with <italic>B. microti</italic>-infected erythrocytes and the parasite infection was monitored daily by blood smear observation, real-time PCR detection, nested-PCR and special antibody responses during 55 days period. The results showed that rats infected with <italic>B. microti</italic> showed a typical sustained infection with strongly antibody responses; however, both goats and dogs infected with <italic>B. microti</italic> only showed transient antibody responses and the parasite was not found by blood smear observation or PCR; neither the parasite nor the special antibodies were detected in experimental chicks and pigs. On the other hand, the present study also experimentally investigated the infectivity of <italic>B. microti</italic> to <italic>Rhipicephalus haemaphysaloides, Haemaphysalis longicornis</italic>, and <italic>Hyalomma asiaticum</italic> three species of ticks outside the genus Ixodes and the transmission experiment of <italic>B. microti</italic> between <italic>H. longicornis</italic> ticks and mice. Results showed that <italic>B. microti</italic> can be detected in the nymph and adult of these species after molting from engorged tick fed on infected mice, but the parasite was not detected in larvae hatching from eggs of engorged female tick fed on the infected mice. Transmission of <italic>B. microti</italic> to mice by infected <italic>H. longicornis</italic> nymphs was confirmed. These results indicated that these domestic animals do not have reservoir competence for <italic>B. microti</italic>, however, three species of ticks out of the genus Ixodes, common in China were successfully infected by <italic>B. microti</italic>, with <italic>H. longicornis</italic> showing the potential of transmitting the parasite to the vertebrate host.</p>