Showing papers on "Babesia published in 1982"

Age resistance in bovine babesiosis: role of blood factors in resistance to Babesia bovis.

Abstract: In vitro cultivation of Babesia bovis in erythrocyte cultures demonstrated that blood from young animals contains a factor(s) responsible for their resistance to severe babesiosis. This factor is independent of antibody, is present in the serum of all young animals tested, and is dialyzable. The presence of this factor results in inhibition of parasite multiplication and the eventual death of the parasite while inside the erythrocyte.

Therapy of Experimental Babesiosis

Abstract: Babesia microtiinfections established in hamsters were treated successfully with clindamycin. Regimens that contained this drug consistently cleared the infection rapidly and without relap...

Babesia, Theileria and Anaplasma spp. infecting sable antelope, Hippotragus niger (Harris, 1838), in southern Africa.

Abstract: Some observations are recorded on blood parasites of sable antelopes. Blood smears of 124 of these antelopes from South Africa and Zimbabwe were examined and 7 were found to be positive for a Babesia sp., identified as Babesia irvinesmithi Martinaglia 1936. A total of 70 of the smears were positive for theilerial piroplasms, while 1 smear had macroschizonts (with cytomeres) and microschizonts of a Theileria (= Cytauxzoon) sp. One blood smear was positive for an Anaplasma sp. Attempts to isolate the Babesia sp. by subinoculating blood from sable to splenectomized and intact sable and splenectomized cattle were unsuccessful. Attempts to infect sable with Babesia bovis and Babesia bigemina were likewise unsuccessful. Theilerial piroplasms reached high levels in a splenectomized sable but could not be transmitted with blood to cattle. The Anaplasma sp. was found to be infective for sheep but not for cattle.

Virulence and heterologous strain immunity of South African and Australian Babesia bovis strains with reduced pathogenicity.

Abstract: DEVOS, A. J., BESSENGER, R. & FOURIE, C. G., 1982. Virulence and heterologous strain immunity of South African and Australian Babesia bovis strains with reduced pathogenicity. Onderstepoort Journal of Veterinary Research, 49, 133-136 (1982). A South African Babesia bovis strain showed loss of virulence after I 0 rapid passages in splenectomized calves. The virulence was comparable with that of an attenuated Australian vaccine strain. Vaccination of cross­ bred Bos indicus cattle with the local strain resulted in a solid immunity to heterologous chaUenge. The degree of protection afforded by the Australian vaccine strain was adequate for controlling challenge with a virulent South African strain, but somewhat less than the degree conferred by the local vaccine strain. Serological observations with the indirect fluorescent antibody test confmned a close relationship between the 2 modified strains. iNTRODUCTION A babesiosis vaccine, consisting of infected blood har­ bouring virulent strains of both Babesia bovis and Babe­ sia bigemina, has been issued from this Institute for many years. This vaccine has not been entirely satisfac­ tory because, amongst other reasons, severe reactions were seen in some vaccinated animals (DeVos, 1978). Recently, Callow, Mellors & McGregor ( 1979) re­ ported reduced virulence of Australian B. bovis strains after rapid passage in splenectomized calves. The pur­ pose of the present study was to compare the virulence and degree of resistance afforded by a South African strain passaged as described by Callow et al. (1979) with that of an attenuated strain used for vaccine production in Australia. MATERIALS AND METHODS Animals The animals used in this study were obtained from a private farm in southern South-West Africa!Namibia where Boophilus spp. , and therefore B. bovis and B. bigemina, were absent. Only animals 1-2 years old and serologically negative for both Babesia spp. were used. The animals, all cross-bred Bos indicus cattle, were alloted to the different experimental groups based on body mass. Strains of B. bovis 1. The South African unmodified F strain was isolated from experimentally produced, tick-transmitted cases (De Vos, 1978) and preserved as stabilate in the gas phase of a liquid nitrogen refrigerator. ACD (citric acid, sodium citrate, dextrose solution) was used as anticoagu­ lant and dimethyl sulphoxide as cryo-protectant (De Vos, Combrink & Bessenger, 1982). 2. In an attempt to reduce its virulence, the South AfricanS strain (DeVos, 1978) was passaged rapidly 10 times in splenectomized calves as described by Callow et al. (1979). After passage, this strain was stored as stabi­ late in a liquid nitrogen refrigerator. It has been the only B. bovis strain used since 1978 in the Onderstepoort babesiosis vaccine and is produced from blood of sple­ nectomized calves inoculated with stabilate of Passage 10. 3. The Australian attenuated vaccine K strain (Dal­ gliesh, Stewart & Duncalfe, 1981) was obtained as Pas­ sage 23 in the form of infected unfrozen blood from the Tick Fever Research C~ntre, Waco!, Queensland. On receipt, it was passaged once in a splenectomized calf before being stored in a liquid nitrogen refrigerator as stabilate of Passage 24.

Studies on the infectivity of Boophilus decoloratus males and larvae infected with Babesia bigemina

Abstract: GRAY, J. S. & POTGIETER, F. T. , 1982. Studies on the infectivity of Boophilus decoloratus males and larvae infected with Babesia bigemina. Oruierstepoort Journal of Veterinary Research, 49, J2 (1982). Babesia bigemina was transmitted by male Boophilus decoloratus and also by intravenous inoculation of a homogenate prepared from infected incubated larval ticks.

Use of cerebellar brain smears in the diagnosis of babesiosis (Babesia bovis) in cattle.

Abstract: Cerebral and cerebellar smears were made from 4 animals acutely reacting to Babesia bovis and 94 animals free from clinical babesiosis. The brain smears were stained by the Giemsa method and examined for the presence of B. bovis parasites. In animals showing clinical babesiosis capillaries congested with parasitised erythrocytes were abundant in cerebral and cerebellar smears. Results obtained from both types of brain smears in animals free from clinical babesiosis agreed closely (83% conformity) as to the presence or absence of parasites. A third group of 39 animals from which cerebral and cerebellar smears were taken was also examined serologically by the indirect immunofluorescent antibody test (IFAT); about 69% of the IFAT positive and doubtful animals showed parasites in the cerebellar brain smears. The existence of false negatives in the IFAT test has been shown and discussed. It has been concluded that cerebellar samples obtained through the foramen occipitale can be used for the microscopic detection of B. bovis parasites in latently infected bovines. This method can also be used in field cases suspected of cerebral babesiosis permitting brain sampling without resorting to the opening of the skull. Such an approach might prove particularly useful in areas where rabies occurs and the animal's head has to be sent to a diagnostic centre.

Serological response of the Mongolian gerbil to Babesia divergens (human strain) infection.

Abstract: Sensitive serological assay systems were developed to measure the antibody responses in gerbils infected with a syringe-passaged human strain of Babesia divergens. High antibody titres were recorded by a triple-layered immunofluorescence assay. An improved ELISA technique, with sucrose gradient-purified parasites as antigen, proved to be almost as sensitive for the detection of specific antibody and correlated well with the immunofluorescence assay. Some gerbil sera with high immunofluorescence and ELISA values agglutinated B. divergens-infected gerbil erythrocytes at room temperature.Antibody was apparently only protective when animals were ‘immunized’ with inert Babesia antigen, either prior to, or—in the case of some stabilates—concurrently with, infection with intact viable parasites. Only minimal serological cross-reaction was seen between the piro-plasms B. divergens and B. musculi in infected gerbils.

Babesiosis in Rodents and Humans

Abstract: ‘Babesiosis’ is the general name applied to infection with organisms belonging to the genus Babesia. These are small intraerythrocytic protozoa in the order Piroplasmida and the phylum Apicomplexa, which divide by binary fission within the red blood cells of mammals and, after a sexual phase, undergo a number of asexual divisions in the invertebrate vector, which is an ixodid tick. Within the mammalian host, the only forms known to be present are those in the blood; thus, the Babesiidae differ from the Theileriidae, to which they are closely related, and the Plasmodiidae, to which they are less closely related, in which one or more phases of division in various tissues precedes the erythrocytic stage. From the point of view of experimental infections, this is an important distinction, because babesiosis can be transmitted by blood stages alone and the whole pattern of natural infection mimicked in the experimental host.

Babesiosis vaccine prepared from soluble parasitic antigen factors isolated from disintegration of Babesia infected erythrocites

Abstract: This invention relates to a method of preparation of a babesiosis vaccine which involves treating a suspension of Babesia infected erythrocytes. The erythrocytes are disintegrated, separated into soluble and insoluble fractions and subsequently fibrinogen and contaminated Babesia antigen is removed from the soluble fraction. The residual soluble fraction is then combined with an adjuvant to form the babesiosis vaccine. The invention also includes within its scope a vaccine derived from the abovementioned method and a method of administration of the vaccine to cattle.