Molecular evidence of Babesia equi transmission in Haemaphysalis longicornis.

We studied the tick, Haemaphysalis longicornis, to determine the possibility of both transovarial and transstadial transmission of Babesia equi. We also studied the usefulness of the needle injection method for pathogenic tick-transmitted organisms including Babesia parasites. Erythrocytes infected with B. equi were injected into the midgut of engorged adults or nymphs using a hypodermic needle passed through the integument. DNA of B. equi in ticks was detected using nested polymerase chain reaction (PCR). B. equi DNA was present in adults, eggs, and larvae, indicating that transovarial transmission occurred. B. equi DNA was present in adults that developed from infected nymphs, and the B. equi antigen was present in their salivary glands, indicating that transstadial transmission occurred. These findings suggest that H. longicornis may play a role in the transmission of B. equi.