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Background: Envenoming by south Asian hump-nosed pit vipers (Genus: Hypnale) is a significant health issue in Sri Lanka and in peninsular India. Bites by these snakes frequently lead to local envenoming, coagulopathy and acute renal failure even resulting in death. Recently the genus was revised and the existence of three species viz H. hypnale, H. nepa and H. zara were recognized. There is, however, a paucity of information on the toxicity of the venoms of these species. Hence, we compared the toxic effects of the three Hypnale venoms using BALB/c mice., Findings: Intraperitoneal median lethal doses (LD50) for H. hypnale, H. zara and H. nepa venoms were 1.6, 6.0 and 9.5 μg protein/g respectively. Minimum haemorrhagic doses for venoms of H. hypnale, H. zara and H. nepa were 3.4, 11.0 and 16.6 μg protein/mouse respectively. The minimum necrotic doses for the same venoms were 15.0, 55.1 and 68.2 μg protein/mouse respectively. Severe congestion and petecheal haemorrhages were observed in lungs, kidneys, liver and the alimentary tract. Histopathogical examination of kidneys revealed proximal tubular cell injury and acute tubular necrosis with intact basement membrane indicating possible direct nephrotoxicity. Hypnale venoms caused pulmonary oedema, hepatocellular degeneration and necrosis, focal neuronal degeneration in brain and extramedullary haemopoiesis in spleen. H. hypnale venom caused all above histopathological alterations at lower doses compared to the other two., Conclusion: Hypnale venoms cause similar pathological changes with marked differences in the severity of the toxic effects in vivo. Therefore, differences in the severity of the clinical manifestations could possibly be seen among bite victims of the three Hypnale species.

Objective: To determine the degree of soil pollution in an area of high prevalence and the risk of exposure to geohelminth infection., Design: A cross-sectional study., Setting: A division of a large tea plantation in Kandy., Subjects: All persons resident in one division of the tea plantation, above the age of 1 year., Measurements: Prevalence of geohelminth infection measured by microscopic examination of faeces of the study group. Soil samples from 38 specific locations, obtained on 3 different occasions, about 6 months apart, analysed for helminth ova. The average temperature, rainfall and the number of rainy days during the sampling period., Results: Of the 99 subjects of the study group, 77.7% were positive for at least one geohelminth infection. The prevalence rates for ascariasis, trichuriasis and hookworm infection were 54%, 28%, and 22% respectively. At the first sampling, 10.5% of the soil samples were positive for helminth ova with 7.8% and 2.6% samples showing Ascaris and Necator ova respectively. At the second sampling of the same locations nearly 40% of the samples were positive for helminth ova with 21.6%, 7.8% and 10.5% of the samples positive for Ascaris, Trichuris and Toxocara ova respectively. At the third sampling, 26.2% of the samples were positive with 21%, 2.6% and 2.6% of the samples positive for Ascaris, Trichuris and Toxocara ova respectively. Necator ova were found only once in 2.6% of the samples of the first sampling. The larger number of samples positive for helminth ova were in the second and the third samplings which coincided with high rainfall in the pre-sampling period., Conclusions: The prevalence of geohelminthiases among the study group was high. Results of soil analysis confirmed continued contamination of soil in and around the home gardens and the work areas with human and dog faeces. With the knowledge of exact locations of soil pollution it was possible to advice the management on remedial measures.

Sera were collected from a minimum of 20 cattle aged nine to 36 months at each of 14 localities in five climatic zones of Sri Lanka. Sera were tested for antibodies to Babesia bovis and Anaplasma by an indirect fluorescent antibody test and a card agglutination test, respectively. Antibodies to B. bovis and Anaplasma were detected in all samples tested from each of 14 and 12 localities respectively. In general, prevalences were consistently high among localities below 1,200 m and lower and more variable in the hill country. Management practice rather than climate was considered to be the main factor influencing prevalences. Management is discussed in relation to the risk of disease outbreak.

A Sri Lankan strain of Babesia bovis (designated A strain) was isolated from larval ticks and prepared for use as vaccine by syringe-passage in 20 splenectomised calves followed by irradiation. The A strain and a vaccine strain of Babesia bovis (designated K strain) brought in frozen form from Australia were used to vaccinate 37 susceptible bulls imported from southern Australia. Rectal temperatures, packed cell volumes, parasitaemias and overt clinical signs were monitored for three weeks following vaccination. The results indicated that the A strain was slightly more virulent than the K strain but suitable for the vaccination of well-supervised cattle.