The genes encoding for immunodominant piroplasm proteins 32 and 33/34 kilodalton (p32 and p33/34) were used as markers for benign Theileria species. These genes yield the 875 and 868 bp fragments using polymerase chain reaction (PCR) amplification. Three unclassified Theileria parasites, named as Theileria sp. (Thung Song), Theileria sp. (Kamphaeng Saen) and Theileria sp. (Ban Pong), were collected from different geographical area of Thailand. Genomic DNAs of these 3 parasites were analyzed by PCR using 2 different sets of primers which could amplify 875 bp and 868 bp fragments. The data suggested that T. sp. (Ban Pong) showed positive PCR fragments of 875 bp (p32) and 868 bp (p33/34). Theileria sp. (Thung Song)　DNA was amplified by only one primer set which could amplify T. sergenti p32 with no detectable amplification of p33/34 gene. In contrast T. sp. (Kamphaeng Saen) showed no amplification fragments using either set of primers. Antigenic comparison between T. sp. (Ban Pong and Thung Song) and benign Theileria parasites (T. sergenti and T. buffeli) revealed the antigenic cross-reactivity of Thai Theileria parasites to T. sergenti and T. buffeli. The data indecated that benign Theileria，genetically and antigenically similar to T. sergenti and T. buffeli, are distributed in Thailand.

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Hepatic microsomal mixed function oxidase system was significantly inhibited/impaired during chloroquine-resistant and chloroquine-sensitive Plasmodium berghei K-173 strain infection in mice compared to normal. Cytochrome P-450, cytochrome b5, aniline-hydroxylase, aminopyrine-N-demethylase and benzo(a)pyrene-hydroxylase were more affected due to chloroquine-sensitive as compared to chloroquine-resistant P. berghei infection in mice. Hepatic microsomal heme levels were increased during P. berghei infection as compared to normal but the increase was more in chloroquine-sensitive as compared to chloroquine-resistant P. berghei infection in mice.

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Surveys were carried out between March and May, 1997 to rule out acute trypanosomosis, following reports from Farmers and field Veterinarians in Mbale and Tororo districts of an outbreak of strange disease causing considerable deaths of cattle, manifesting with anaemia, bleeding through the skin and ears, before death and, petechial haemorrhages on the tongue and enlarged spleen observed at postmortem. A total 808 cattle were examined by Buffy Coat Technique (BCT) for trypanosomosis and tsetse trapping was done in 5 subcounties in Mbale and Tororo districts. Bovine trypanosomosis was found to be prevalent in 8.7% to 26.5% of the cattle in Mbale district and in 27.8% to 34.8% of the cattle in Tororo district. Trypanosome infections found were largely due to Trypanosoma vivax. Cattle infected with trypanosomosis had a lower mean PCV (23.6±0.64) than those free (mean PCV of 26.9±0.25). Of the cattle examined, 43% had PCV (packed cell volume) below or equal to 24, hence manifested anaemia. According to the findings, clinical signs and high mortality, the outbreak was sue to haemorrhagic T. vivax. This is the first time an outbreak of haemorrhagic T. vivax is reported in Uganda. Tsetse flies caught were predominantly of the Glossina fuscipes fuscipes species (F/T/D/: 0.7-3.0) but few were of G. pallidipes (F/T/D/: 0.1). Immediate implementation of integrated control programme involving application of pour-on, chemotherapy and deployment of insecticide impregnated traps was recommended.

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Two experimental cross-infections of beagle puppies with the Giardia intestinalis are described. In each experiment three littermates at the age of 18 and 24 days were included. In each group, two puppies were orally inoculated with cysts, the third animal served as a control. One of the inoculated puppies in each group was immunosuppressed by dexamethasone. In the first experiment, an isolate from lamb was used for the inoculations at a dose of 20,000 cysts pro toto, in the second experiment an isolate from pig at a dose of 30,000 cysts pro toto. Feces were examined regularly for Giardia cysts, blood samples were analyzed for specific anti-Giardia IgG and IgM antibodies by means of the IFAT technique and parameters of non-specific immunity were determined. The attempt at cross- transmission failed even in markedly immunosuppressed puppies. Neither release of cysts nor seroconversion of circulating specific antibodies were detected. We assume that cross-infection of dogs can occur only under exceptional circumstances. Dogs do not represent significant source of Giardia intestinalis infection for man, even during their mutual close coexistence.

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The reaction of lymphocyte populations, in iNOS-/- mice and wildtype control mice, to Babesia microti infection was investigated in this study. During the course of infection, in both groups of mice there was gross enlargement of the spleens but the spleen cell population decreased by 50%. At peak parasitemia iNOS-/- mice had a low lymphocyte count and on overall, a slight increase in leukocyte population in peripheral blood. On the other hand control mice showed a significant increase in leukocyte population but lymphocyte numbers remained unchanged. During infection the iNOS-/- mice had a higher percentage of B lymphocytes and CD4⁺ T cells in the spleen, compared to the control mice. In response to B. microti infection iNOS-/- mice produce less IL-4, but more IFN-γ compared to control mice. Parallel to the higher percentage of B cells, iNOS-/- mice also produced higher amounts of B. microti-specific antibodies. These results suggest that in the early stages of infection NO protects the lymphocytes against B. microti invasion and that the immune defense in iNOS-/- mice involves to a large extent humoral immune response.

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