Rickettsioses in the central hills of Sri Lanka: serological evidence of increasing burden of spotted fever group.

OBJECTIVES: To study the epidemiology, clinical features, and changing pattern of rickettsial infections on the western slopes of the hilly Central Province of Sri Lanka over 6 years. METHODS: All patients with rickettsial infections who presented to the Teaching Hospital, Peradeniya were studied prospectively from January 2002 to December 2007. An immunofluorescent antibody assay (IFA) was used to confirm the diagnosis. RESULTS: Of the 371 clinical cases of rickettsial infection, 122 underwent IFA to confirm the diagnosis. Species-specific IgG antibodies were positive in 105/122 (86.1%) cases: 43/105 (40.9%) to Rickettsia conorii and 6/105 (5.7%) to Orientia tsutsugamushi, with mixed antibody reactivity to more than one antigen in 56/105 (53.3%) cases, including Rickettsia typhi in 27/105 (25.7%). Among those with mixed IgG reactivity, IgM assays were used to detect pathogens responsible for acute infections. Finally, a total of 55 spotted fever group (SFG) infections, seven scrub typhus infections, and one case of murine typhus were identified. Of the 105 positive cases, 53 (50.5%) were male and 52 (49.5%) were female, and the mean age was 40 years (range 11-83 years). In the SFG patients, 13/55 (24%) had severe vasculitis with fern leaf type skin necrosis and 17/55 (31%) had arthritis. Three patients (5%) had an altered level of consciousness. A patient with scrub typhus had transient deafness. None of the 105 patients had an eschar. CONCLUSIONS: It appears that SFG rickettsioses are on the rise in the hilly Central Province of Sri Lanka, whilst murine typhus and scrub typhus are present at a lower rate.

Admission to medical schools in Sri Lanka: predictive validity of selection criteria.

OBJECTIVE: To assess the extent to which current selection criteria predict success in Sri Lanka's medical schools. METHODS: The study sample consisted of all students selected to all six medical schools in two consecutive entry cohorts. The aggregate marks of these students at the General Certificate of Education (GCE) Advanced Level examination, the district of entry, admission category, candidate type (school/private) and gender, were identified as entry point variables. Success in medical school was measured in four ways: the ability to pass the first summative examination and the final examination at the first attempt, and obtaining honours in either examination. Multivariate analysis using logistic regression was used to assess the extent to which these entry point factors predict variability in outcome measures. RESULTS: Aggregate scores among the 1740 students in the study sample ranged from 212 to 356, with a median of 285. The male:female ratio was 1.4:1. Private candidates (taking the examination for the third time) accounted for 22% of students. Being a school candidate, female and having a higher aggregate score, were the only independent predictors of success for all four outcome measures. The aggregate score alone accounted for only 1-7% of the variation in performance in medical school. CONCLUSIONS: Marks obtained at the A Level examination (the only academic criterion currently used for selection of medical students in Sri Lanka) is a poor predictor of success in medical school.

Soil contamination with geohelminth ova in a tea plantation.

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.

Adult filarial worm (Wuchereria bancrofti) in a benign ovarian tumour.

A case of an adult filarial worm (Wuchereria bancrofti) associated with a benign ovarian tumour and a cyst is presented. Possible reasons for the findings of a well preserved part of the worm and a foreign body granuloma in the lymphatic subendothelium are discussed.

Myiasis due to Cardylobia anthropophaga, the 'Tumbu fly' in a Sri Lankan infant.

A case of myiasis due to Cardylobia anthropophaga (Blanchard) (Diptera: Calliphoridae), the 'Tumbu fly', is reported for the first time in Sri Lanka, in a 10 month old infant. The infection was acquired in Zimbabwe. The child had appeared 'unwell' for nearly a week before the detection of the skin lesions. The main clinical features were irritability, restlessness and the appearance of three small lumps on the scalp behind the right ear. Identification of the fly larva and the management of myiasis are discussed.

Effectiveness of mass treatment with mebendazole in the control of soil transmitted helminths in Sri Lanka.

The efficacy of a single large dose of mebendazole was compared with the three-day multiple dose in mass treatment. The subjects were selected from among plantation workers of a tea estate in Kandy. The multiple dose regime showed consistently better egg reduction rates and cure rates when compared to the single large dose in subjects harbouring one or more soil-transmitted helminths.

Infections in the malnourished: with special reference to malaria and malnutrition in the tropics.

The inter-relationship of malnutrition and infections is generally accepted as being synergistic, one promoting the other. Nevertheless, numerous published reports are available which highlight the contrary, that is, antagonism of poor nutrition to infections. This presentation is a review of such publications with emphasis on malaria and malnutrition in the tropics. The data presented suggest that the effect of poor diets on human malaria is related to the level of protein and energy intake, which in turn have important bearings not only on clinical nutrition but also on nutrition policy and planning, particularly in famine and famine relief. The data highlight the necessity for the integration of nutritional programmes and anti-malarial activities in areas where famine and malaria co-exist.

Increased severity of malaria infection in rats fed supplementary amino acids.

Infection with Plasmodium berghei malaria is severely inhibited in rats fed on a low protein diet. A range of amino acid supplements was added to a 4.2% casein diet to determine whether the relationship between level of infection and protein content could be attributed to the dietary amounts of the essential amino acids. Significant increases in levels of infection were achieved by supplementation with specific combinations of amino acids. Threonine was most effective in increasing the degree of parasitaemia but its effect was further enhanced when it was combined with dietary excess of certain other amino acids, notably valine, isoleucine and methionine.

Resistance to superinfection with Plasmodium berghei in rats fed a protein-free diet.

The development of resistance to reinfection with Plasmodium berghei was studied in rats in which the primary infection had been almost totally suppressed by feeding a protein-free diet (peak parasitaemia 0.5%; patent for only the first four days after inoculation) On Days 5, 9, 15, 23 and 28 after primary inoculation groups of animals were challenged with the same strain of parasite. At the same time the diet was changed to that of a 17% casein formula. The development of resistance as judged by the level of parasitaemia following challenge reached a significant level nine days after the primary inoculation and almost complete protection by Day 23 of the study. The protective activity was immunological since it could be transferred to other animals by a single intravenous injection of a suspension of spleen cells from infected donors. The study illustrates that infected animals experiencing severe protein malnutrition are still capable of mounting a substantial immune response to malaria.

The influence of dietary protein on the development of malaria.

In the course of malarial infection in an animal model, the dietary level of protein proved to be important. Synthetic diets were used, identical in every respect other than the type and amount of protein. Reducing the protein content of the diet led to a decrease in the level of infection and a protein-free diet almost totally suppressed the disease. These findings were obtained in rats infected with either Plasmodium berghei or Plasmodium vinckei; when the dietary protein was in the form of casein or albumin; and when well-nourished or previously undernourished animals were used. The study indicates that acute and chronic undernutrition may protect a host against severe malarial infection.