Hepatozoon canis development in Amblyomma cajennense and Amblyomma ovale (Acari: Ixodides) experimentally infected

Abstract

Experimental infections using ticks Amblyomma cajennense and Amblyomma ovale will be carried out from dog with naturally occurring Hepatozoon canis infection. Amblyomma cajennense nymphs will be fed on a naturally infected dog, or they will be infected by percutaneous injection of blood. Samples of nymphs fed on an infected dog will be collected every day for observation of the course of the infection in the tissues of the ticks. Ticks will be dissected and smears of intestine will be prepared and examined under a light microscope. Hemolymph smears will be made from percutaneously injected nymphs at 30 min and 1, 2, 12, 24 and 48 hr postinjection. Slides of hemolymph smears will be stained and examined. Nymphs infected by natural feeding or by percutaneous injection will be incubated until postmolt. Adults ticks will be dissected and smears of intestine will be prepared and examined for the presence of oocysts. Amblyomma ovale adults will be fed on H. canis positive dog and hemolymph smears will be made from fixation to detachment at each 48 hours and until 48 hours after engorgement. The purpose of the present study is to infect experimentally A. cajennense and A. ovale with H. canis and identify forms of development of the protozoan in these ticks. The results obtained will indicate Amblyomma species as potential vector of H. canis in rural areas of Brazil. (AU)