The transovarial transmission of Babesia caballi by Hyalomma truncatum

Babesia caballi, isolated from a horse that originated from South West Africa/Namibia, was transmitted transovarially by adult Hyalomma truncatum. B. caballi proved to be highly infective for adult H. truncatum. Forty-five per cent of ticks feeding on a reacting animal with an extremely low parasitaemia became infected. In spite of a low parasitaemia, the ticks were severely affected by the parasite. Seventy per cent of the infected ticks either died during oviposition or after laying only a few eggs. The features of the infection in horses were: a prepatent period of 10 days, very low parasitaemias with low pathogenicity and spontaneous recovery of the infected animals.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

The transstadial transmission of Babesia caballi by Rhipicephalus evertsi evertsi

Rhipicephalus evertsi evertsi larvae were fed on the ears of rabbits. Seven days after larval infestation, unfed, newly moulted nymphae were manually removed to infest a splenectomized donkey showing a patent Babesia caballi infection. Engorged nymphae were collected from the donkey and the ensuing adult ticks were placed on a susceptible horse. The horse contracted a B. caballi infection showing a prepatent period of 19 days after tick infestation. A very low parasitaemia, (highest score 2), which was patent for only 10 days, was recorded. The lowest packed cell volume recorded was 16 %.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

The fine structure of developmental stages of Babesia caballi in the salivary glands of Hyalomma truncatum

The development of Babesia caballi in the salivary glands of Hyalomma truncatum was studied at the electron microscopic level. Kinetes were first observed in the salivary glands of ticks on Day 2 of tick feeding and on each subsequent day of feeding until engorgement on Day 8. Sporogony appeared to involve the formation of cytomeres. After continued nuclear division, sporozoites formed when individual rounded nuclei were incorporated into portions of cytoplasm. Sporozoites were first observed on Day 4 of tick feeding and contained typical Babesia spp. organelles with a polar ring and up to 4 rhoptries, spherical bodies, a nucleus, mitochondria, endoplasmic reticulum and micronemes. The infection rate in the ticks was approximately 80%.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

Evaluation of a 3 ml heartwater (cowdriosis) infective blood vaccine dose

Three milliliters of blood from the present commercially produced heartwater infective blood vaccine (Ball3 stock) was experimentally tested in sheep and cattle for infectivity and efficacy. Results obtained for this vaccine dose were statistically not different from results for the prescribed 5 ml vaccine dose.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

In vitro cultivation of Babesia equi: detection of carrier animals and isolation of parasites

By means of an in vitro culture technique, 75 samples of horse blood were examined for Babesia equi, a causative agent of equine piroplasmosis. At the time of culture initiation, 15 samples were microscopically positive for B. equi, and this was subsequently confirmed by culture diagnosis. Sixty samples showed no parasites in Giemsa-stained thin blood smears. However, after the culturing process, parasites were found in blood smears of 36 of these samples. The sensitivity of the in vitro culture method was such that 2,5 µl (1/40 of the usual volume used for the above mentioned samples} of packed erythrocytes obtained from a carrier horse still yielded positive results after cultivation. Cultures were initiated from blood samples stored for up to 120 h at 8º C in vacuum tubes containing EDTA as anticoagulant. These results show that the in vitro culture method is highly sensitive. It can be used to identify B. equi carrier horses, to evaluate the effects of chemotherapeutic intervention, and to isolate field strains of B. equi or further characterization.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

An investigation into the clinical pathological changes and serological response in horses experimentally infected with Babesia equi and Babesia caballi

Serologically negative horses, as determined with the indirect fluorescent antibody test (IFA), were infected with Babesia equi and 60 days later with Babesia caballi. The only clinical signs of disease observed in these animals were a febrile reaction and slight icterus. Haematological changes included a drop in haematocrit and haemoglobin concentration, as well as lowered platelet counts. The serum concentrations of albumin, iron and phosphorus were lowered. Mildly elevated serum bilirubin and fibrinogen concentrations were observed. Antibody titres were determined with the IFA and complement fixation (CF) tests. Antibodies to B. equi were first detected between Days 10-19 and 12-38 with the IFA and CF test, respectively, while the corresponding IFA periods for B. caballi were 6-8 days after infection. The parasitaemia of both B. equi and B. caballi infections never reached the 1% level.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu201

Chemotherapy of experimental Besnoitia besnoiti infection in rabbits

Rabbits were infected with a bovine strain of Besnoitia besnoiti parasites derived from VERO cell cultures. Oxytetracycline*, given at 30 mg/kg i.m. simultaneously with infection, prevented the development of orchitis. The controls received no treatment. All infected animals showed a transient febrile reaction. It is concluded that oxytetracycline has some therapeutic potential against Besnoitia besnoiti and that rabbits are suitable models for therapeutic trials.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

The isolation and transmission of an unidentified Babesia sp. to cattle by Hyalomma truncatum Koch 1844

An unidentified Babesia sp. which causes a mild disease in cattle was isolated in a splenectomized ox that received pooled blood from field cattle. That this organism is pleomorphic and resembles Babesia occultans makes it difficult to differentiate between these organisms microscopically. Initially, it was suspected that this Babesia could be B. occultans. Several attempts to transmit this parasite transovarially with Hyalomma marginatum rufipes, the vector of B. occultans, failed. Continued efforts to identify possible vectors, using Boophilus microplus, Rhipicephalus evertsi evertsi and Rhipicephalus appendiculatus, all failed. The only tick thus far identified that could have transmitted the infection transovarially in the adult stage was the two-host tick Hyalomma truncatum.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

A survey of the incidence and importance of the tick-borne diseases heartwater, redwater and anaplasmosis in the heartwater-endemic regions of South Africa

In an almost 50% response to a survey questionnaire, farmers in the heartwater-endemic regions of South Africa indicated that they were experiencing losses of 1,3, 0,3 and 0,2% in cattle due to heartwater, redwater and anaplasmosis, respectively. In small stock, the heartwater mortality was 3,8%. Only 35% of cattle farmers and 15% of farmers keeping sheep and goats, vaccinate their animals against heartwater. It would seem that the present vaccine does not control heartwater adequately and, with 9% of farmers claiming poor protection after immunization, it would be difficult to recommend wider use of the heartwater vaccine. Likewise, vaccination against redwater and anaplasmosis on 11,8 and 14,2% of farms, respectively, appears to have had no beneficial effect on the mortality rates of these diseases. Many farmers still believe that very few or no ticks should be seen on cattle. In fact, it would appear that a considerable proportion of farmers find so few ticks on their cattle, that the frequency of acaricidal treatment is in many cases too high. Although there is no correlation between the incidence of heartwater and the intensity of tick control, there is also no serological evidence to support the possibility of an endemically unstable condition. The concept that endemic stability as a means to control heartwater in cattle can be achieved by allowing more ticks on animals, has not yet been established. The overall impression is that farmers do not regard heartwater in cattle as such a serious problem as it is generally believed to be. In small stock, however, heartwater is a severe constraint in the bushveld regions of the Transvaal and in the valley bushveld of the eastern Cape Province. In the latter, it is particularly Angora goats that are affected.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

The transovarial transmission of Babesia trautmanni by Rhipicephalus simus to domestic pigs

Rhipicephalus simus was, for the first time, experimentally proven to be a transovarial vector of Babesia trautmanni of domestic pigs. The nymphal and adult progeny of experimentally infected female ticks transmitted the infection to 2 susceptible splenectomized pigs. Features of the infection included a prepatent period of 6-8 days post-tick infestation, a febrile reaction for 3 days and a maximum parasitaemia score of 15 (more than 6 parasites per 300 red blood cells). Other clinical signs in both pigs were mild inappetence and listlessness. Both pigs recovered without any antibabesial therapy.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201