naphthoquinones and Tick-Infestations

Four hand-reared, naïve roan antelope, 4 months of age, were exposed to naturally infected pasture on a game farm in Mpumalanga Province, South Africa, where roan are known to die from theileriosis. Various clinical parameters were recorded during this period. The predominant ticks parasitising these animals at the time (January to February), were Rhipicephalus appendiculatus and Rhipicephalus evertsi evertsi adults. After a period of 5 weeks the animals developed signs of clinical theileriosis and were treated with buparvaquone to prevent mortality. Primary hyperplasia of the local draining lymph nodes (Lnn. anorectales) near the feeding site of adult R. evertsi evertsi indicated possible transmission of Theileria sp. (sable) by this tick species. After recovery from theileriosis, these animals were confirmed carriers of Theileria sp. (sable) by PCR (polymerase chain reaction) and DNA probe analysis. Laboratory-bred larvae and nymphs of R. evertsi evertsi and R. appendiculatus respectively, were fed on the ears of these roan antelope. Salivary glands from moulted and prefed adult ticks of each species were dissected and stained for Theileria spp., and the PCR and DNA probe applied to a representative batch of dissected glands. R. appendiculatus adults collected from grass in infected camps were also dissected after prefeeding them on rabbits. Salivary glands of both tick species showed infected acini on staining and were also positive for Theileria sp. (sable) only, on multiprotozoal PCR-screening analysis. There was no statistical significant difference between the infection rate and the intensity of infection between the two tick species. R. appendiculatus ticks collected from grass were also PCR-positive for Theileria sp. (sable).

Topics: Animals; Animals, Wild; Antelopes; Antiprotozoal Agents; DNA, Protozoan; Male; Naphthoquinones; Polymerase Chain Reaction; Rhipicephalus; Salivary Glands; South Africa; Theileria; Theileriasis; Tick Infestations

Two trials were conducted to compare the efficacy of parvaquone and buparvaquone for the treatment of naturally acquired East Coast fever (ECF, Theileria parva infection) which, if untreated, is almost invariably fatal in European breeds of cattle. In the first trial 28 naive cattle were exposed in a paddock infested with ticks carrying a virulent form of the disease. Twelve were treated with each drug when they developed clinical ECF. All 24 cattle were cured. In the second study, 100 cases of ECF occurring naturally on farms in Kenya were treated, 50 with each drug. Parvaquone cured 44 (88%) buparvaquone cured 45 (90%). Intercurrent infections, predominantly anaplasmosis and bacterial pneumonia or scour, were treated specifically. It is concluded that parvaquone and buparvaquone are similarly effective in curing ECF and cure rates are maximised by accurate diagnosis and prompt treatment of both ECF and intercurrent infections.

Topics: Administration, Topical; Animals; Antimalarials; Biopsy; Cattle; Female; Fever; Injections, Intramuscular; Insecticides; Kenya; Male; Naphthoquinones; Nitriles; Parasitemia; Pyrethrins; Random Allocation; Theileriasis; Tick Infestations