P Verle

The unreliability of the Kato-Katz technique limits its usefulness for evaluating S. mansoni infections

The Kato‐Katz technique, a (semi) quantitative stool examination technique, is generally recommended for diagnosis and evaluation of Schistosoma mansoni infection by schistosome experts. However, egg counts are subject to important variability. In order to quantify the reproducibility of egg counts using the Kato‐Katz technique, field data of 1255 observations on 299 subjects infected with Schistosoma mansoni were analysed. Agreement between repeated observations was assessed both categorically (kappa statistic) and continuously (analysis of variance). The day‐to‐day variation of egg counts was much greater than the variation due to different observers or different slides. The quantitative reproducibility was low: the weighted kappa statistic was 0.39 between specimens of different days, 0.62 between slides of the same specimen and 0.81 between observers of the same slide. Therefore the classification of individual patients into groups based on egg counts, used as a measure of morbidity, must be interpreted with great care, especially in longitudinal studies. Usefulness of the Kato‐Katz technique appears limited. Its reproducibility is low. It cannot be recommended as a routine test in a primary health care setting or in a hospital laboratory because safety and detection of other parasites are better assured by other techniques. It can be used in epidemiological studies and evaluation of schistosomiasis control programmes, but here too, other techniques might be preferred.

Efficacy of artesunate and praziquantel in Schistosoma haematobium infected schoolchildren

Praziquantel is the current mainstay for morbidity control of schistosomiasis. Artemisinin and its derivatives, widely used for the treatment of malaria, also display antischistosomal properties. The present study is an effort to assess the therapeutic efficacy of artesunate, an artemisinin derivative, in Schistosoma haematobium infections in a human population. The efficacy of artesunate and praziquantel were comparatively studied in primary schoolchildren from two villages, Lampsar (n=180) and Makhana (n=108), located along the Lampsar river in the delta of the Senegal River Basin in Northern Senegal (West Africa). In each village, half of the infected children were treated with a single oral dose of 40 mg/kg praziquantel and half with artesunate following the recommended malaria monotherapy regimen. For both drugs, cure and egg count reduction rates were, without apparent explanation, higher in Makhana than in Lampsar. In both villages, high and nearly comparable egg count reduction rates were obtained with both drugs at each follow-up after treatment (5, 12 and 24 weeks) in the heavy infected group of children (>50 eggs/10 ml of urine). No major adverse effects were observed. The results demonstrate that artesunate is effective against S. haematobium, but the results obtained with praziquantel were consistently better.

Prevalence of intestinal parasitic infections in northern Vietnam

We surveyed the prevalence of parasitic infections in the mountainous province of Hoa Binh, north‐west Vietnam, involving 526 households of six ethnic groups: Muong, Kinh, Dao, Thai, Tay and Hmong. Eggs or cysts of at least one parasite species were detected in 88% of stool samples (n = 2522). Prevalences of nematodes were high among all ethnic groups: hookworm (52%), Trichuris trichiura (50%) and Ascaris lumbricoides (45%). Ascaris infection appeared to be lower in households owning a latrine, was highest among children and decreased with age. Prevalence of hookworm rose during childhood, remained high until old age, was highest among adult women, but was not linked to anaemia. Eggs of Chlonorchis spp. were found in 126 (5%) individuals (of the Muong, Kinh or Thai groups only). Chlonorchiasis increased with age and was highest among adult men. Taenia eggs were found in three individuals (0.1%). Giardia lamblia was found in all districts and among all groups and the prevalence of infection was estimated at 3%.

What is the effect of combining artesunate and praziquantel in the treatment of Schistosoma mansoni infections

Summary A group of 110 individuals with Schistosoma mansoni infection was investigated. Patients were allocated to one of three treatment groups and given artesunate or praziquantel alone or both in combination. Combined artesunate–praziquantel significantly increased the number of individuals cured at 5 weeks post‐treatment, but at 12 weeks was only better than artesunate alone and at 24 weeks there was no statistically significant difference between the three groups. Egg count reduction rate was similar to the rate obtained with praziquantel used alone.

Control of malaria vectors: cost analysis in a province of northern Vietnam

Summary The cost of permethrin‐treated bednets (50% EC; 0.2 g/m2, 2 rounds per year) was compared to the cost of residual spraying with lambdacyhalothrin 10% WP (0.03 g/m2, once yearly) in Hoa Binh, a mountainous province in northern Vietnam. Calculations of the amounts of insecticides needed were based on national guidelines, on data from a cross‐sectional survey and on district activity reports. The actual cost of insecticide required per person per year was lower for impregnation (US

ParaSight‐F test to diagnose malaria in hypo‐endemic and epidemic prone regions of Vietnam

0.26) than for spraying (US

Glucose-6-phosphate dehydrogenase deficiency in northern Vietnam.

0.36), but the difference was smaller than expected. The total cost for impregnated bednets per person per year amounted to US

Use of Secondary Slags in Completely Recyclable Concrete

0.90 compared to US

A simple field test for detecting pyrethroids on impregnated nets

0.47 for spraying. The determining factor was the cost of the net, amounting to US

Efficacy of artesunate against Schistosoma mansoni infections in Richard Toll, Senegal.

0.58 per person per year, assuming a 5‐year life of the net. Other material (excluding nets), labour and transport combined, accounted for only 17% of the impregnation cost and 23% of spraying expenses. However, for the National Malaria Control Programme of Vietnam, the cost per person per year for impregnated bednets amounted to US