A three year follow-up of chemotherapy with praziquantel in a rural Zambian community endemic for schistosomiasis mansoni.

A resurvey for schistosomiasis mansoni was carried out in a community 2 years after chemotherapy with praziquantel was stopped. Data on infection status, morbidity, subjective symptoms, and liver and spleen enlargement were collected from participants. Results show that prevalence of Schistosoma mansoni infection and subjective symptoms of morbidity have returned to pretreatment levels. However, the population mean egg output remained low. Liver and spleen sizes in individuals who received treatment have shown a further decline compared to 2 years before. We conclude that selective mass chemotherapy with praziquantel can give the community as a whole a respite from schistosomiasis morbidity for at least 2 years despite an increase in prevalence.

Reduction in prevalence, intensity of infection and morbidity due to Schistosoma mansoni infection in a community following treatment with praziquantel.

Five hundred and twenty-three individuals from an area endemic for Schistosoma mansoni infection were followed for a 16 month period in a population-based study in rural Zambia. Those found infected in each of five surveys were treated with praziquantel (40 mg kg-1 body weight). Data on prevalence, intensity of infection and morbidity (intestinal symptoms and liver and spleen enlargements) were also gathered. At the end of the study, prevalence had fallen from 64.8% to 11.5%, intensity of infection had dropped from 28.2 to 0.5 eggs per gram of stool (geometric means) and morbidity showed marked reduction.

Profiles of heterophile antibody to various mammalian erythrocytes in rural populations of Zambia.

Heterophile antibodies to sheep red blood cells (SRBC), rabbit red blood cells (RRBC), horse red blood cells (HRBC), murine (rat) red blood cells (MRBC) were investigated in a total of 416 serum samples from two rural areas of Zambia where major parasitic diseases are endemic. Distribution of antibody titers to RRBC were significantly different between the two study areas, whereas titers to SRBC were not significantly different. Sheep RBC's did not reveal a uniform consistent difference between the two communities with respect to schistosomiasis and malaria. Rabbit erythrocytes showed significant differences (P less than 0.05) between parasitologically positive and negative samples for schistosomiasis and malaria, respectively. No significant difference was observed between sexes, although females generally have a slightly higher titer for both SRBC and RRBC than males. No significant agglutinins were detected to HRBC and BRBC. Agglutinins to MRBC were generally too high to be of any differential value. It is suggested that sheep and rabbit erythrocytes might be useful probes for evidence of exposure to parasites and assessment of humoral immunologic status, albeit nonspecific. Further, it is inferred that the incidence of infectious mononucleosis in this region is rather low. A controlled investigation into the distribution of E-B viruses is suggested to explain absence of I-M-like agglutinins in a region climatically conductive to existence of arborviruses in general, and the E-B virus group in particular.

Revitalizing primary health care

Primary health care was started in the Isoka District of Zambia in 1981. The programme was modified in 1984 so as to make it more effective: government support was given to local communities, illiterate community health workers were admitted to the service, course content was simplified, training was transferred from the district hospital to the health centres, and local communities and rural health centre staff were given an increased part in the training and regular supervision of community health workers. Careful planning and management has resulted in more efficient implementation of primary care. Our preliminary results indicate that it is possible for a developing country to make significant advances by using its meagre resources judiciously

The relationship between morbidity and intensity of Schistosoma mansoni infection in a rural Zambian community.

Six hundred and ninety-three individuals from an area endemic for S. mansoni infection had parasitological and physical examinations done. A morbidity questionnaire was also administered to each participant. Among those with S. mansoni infection, there was significant increase in watery diarrhoea, bloody diarrhoea, blood in stool and hepatomegaly. The severity of the disease appears to be directly related to the egg load and therefore these results give further justification for treatment of high intensity age groups in community based chemotherapy programmes designed to reduce morbidity in endemic areas.

Evaluation of conjunctival pallor in the diagnosis of anaemia.

The diagnosis of anaemia using conjunctival pallor was evaluated using the concept of predictive values. The presence or absence of pallor in 951 individuals and their haemoglobin levels were matched, defining haemoglobin of 10 g dl-1 or less as representing anaemia. The sensitivity and specificity of the test of pallor were 18.6% and 95.8%, respectively. At 16.3% prevalence of anaemia the positive and negative predictive values were 46.3% and 85.8%, respectively. The findings suggest that conjunctival pallor as a screening test for anaemia may not be very reliable.

Use of symptoms and signs for diagnosis of Trypanosoma brucei rhodesiense trypanosomiasis by rural health personnel.

The results are described of a study of 60 patients with sleeping sickness from north-east Zambia together with 60 hospital controls and 27 nearest-neighbour controls. Eight symptoms were significantly commoner among sleeping-sickness patients than among either set of controls, and some of these symptoms were used to devise a scoring system for use by rural medical personnel. Although most patients reported a short history of the illness, almost 90% had abnormal cerebrospinal fluid, and there was a significant tendency for the cerebrospinal fluid of adults with a longer history of sleeping sickness to contain trypanosomes. Enlargement of lymph nodes was significantly more frequent among the patients than among the controls, but often the submandibular, axillary, or inguinal rather than the posterior cervical nodes were enlarged. Signs associated with involvement of the central nervous system were common, but the cheiro-oral reflex was non-specific, also occurring frequently among hospital controls.

Evaluation of selected symptoms in the diagnosis of Schistosoma mansoni infection.

Data on morbidity associated with S. mansoni infection was gathered using a questionnaire before parasitological screening was done in a rural Zambian community. Blood in stool, bloody diarrhoea and watery diarrhoea were found to be significantly associated with S. mansoni infection. Levels of sensitivity, specificity and predictive values were calculated for each symptom. On the basis of results obtained we speculate that these symptoms could be used by peripheral health workers in making early diagnosis of the disease in the absence of laboratory diagnostic tests.

The prevalence and distribution of schistosomiasis in Zambia.

PIP: This paper attempts to approach an accurate report of prevalence of schistosomiasis in Zambia by bringing together several reports. A review of some early prevalence studies in Zambia shows the prevalence of S. hematobium infection to be (14-40%) and that for S. mansoni to range from (0-7%), in the Northern and Luapula Provinces. The areas around Lakes Kariba in the south, and Bangweulu in the north had prevalence rates of (3-35%) for S. hematobium and (2-6%) for S. mansoni. A nationwide survey found the overall prevalence of S. hematobium to be about 16%. The Gwembe Valley in the South had the highest prevalence of 57.9% for S. hematobium; S. mansoni with a prevalence of (45-77%) in the Northern Province from more recent studies is not very widespread. A comprehensive study performed between 1969-73 covered almost the entire rural population and found an overall prevalence of 16.8%, varying greatly between ecozones. The 5-14 year age group showed the highest prevalence. A 1976-82 study of rural primary school children in several provinces found high prevalence rates. Specimen gathering and analysis is described for most studies analyzed, revealing some inconsistencies threatening the reliability of data. Available data do show the spotty and local nature of the prevalence rates between areas. There have not been many studies of S. mansoni prevalence, possibly due to the difficulties involved with the collection of stool specimens, but prevalence (especially seasonal) has been shown to be high in certain areas (although low generally). The areas around the 2 major lakes show considerable prevalence of both parasites, and further study is needed on the health impact of man-made lakes in Zambia and elsewhere.^ieng