East Coast fever
The coast fever or East Coast fever is caused by the protozoan parasite Theileria parva disease of the domestic cow, which is found in tropical Africa and is transmitted by ticks Rhipicephalus appendiculatus the type.
Pathogen
Theileria parva is a protozoan parasite that is part of the subordination Piroplasmorina and thus related, among others, with the Babesia. The genus name honors the Theileria Swiss- South African veterinarian Arnold Theiler. The sporozoites live in the salivary glands of the tick and return them to bite into the blood.
There are three known subspecies of T. parva: T. p. parva and T. p. lawrencei are very virulent, T. p. bovis less. The subspecies parva bovis and are usually transmitted from cow to cow, the subspecies lawrencei used the African buffalo as a reservoir host.
Life cycle
The into the blood came with the tick salivary sporozoites infect the lymphocytes and develop in these within 5 to 10 days to schizonts. These stimulate the lymphocytes to cell division, with the schizont also communicate with each cell division. The infected cell population proliferates in the sequence and is distributed throughout the lymphoid system. Later, develop some of the schizonts to merozoites, the change of the lymphocytes in the red blood cells. Occur again at some divisions of the parasite within the red blood cells, the blood cell itself but no longer divided. These infected cells are taken at a tick bite and develop in the tick again to sporozoites that infect the salivary glands, from where they can proceed with the next bite on another cow.
Symptoms
By the uncontrolled proliferation of lymphocytes occurs in infected animals to form a clinical picture, the macroscopically similar to a lymphosarcoma. The lymph nodes swell greatly, and it can also lead to the infiltration of other organs by parasitized lymphocytes. At the same time suffering from a high fever affected cattle to about 42 ° C. Death is usually 18 to 24 days after infection, usually by pulmonary edema and in some cases massive internal bleeding. Surviving animals are after recovering from infection against the causative subspecies immune, but not against the other subspecies.
Treatment
The treatment against Theileria spp. done by Parvaquon and deduced substance Buparvaquone. By this treatment can be achieved in the early stages of the disease, usually a cure; in advanced cases, the prognosis is, however, reserved with Parvaquonen even with treatment.
Prevention
Vaccination against Theileria parva is not available at this time. In practice, a deliberate infection with the parasite in combination with the simultaneous administration of oxytetracycline is applied. Although this material is in a clinically apparent infection only insufficient effect against the parasite, but is suppressed in the early handover its life cycle.
Alternatively, immunization against coast fever also be achieved by a deliberate infection with doses of Parvaquonen after seven to nine days. This method is less common in practice, however, since it requires two times of capture of the cattle.
Animals should be immunized three to four weeks before the removal in a Enzootiegebiet. A prevention of tick control is also possible, however, is rarely practiced because of the high cost.