The WHO dose pole for the administration of praziquantel is also accurate in non-African populations

In 2001, WHO developed a pole for the administration of praziquantel without the use of weighing scales, with encouraging results in African populations. In the present study, the pole was tested on height/weight data from 9354 individuals from 11 non-African countries. In more than 98% of the individuals (95% CI 97.8-98.4) the pole estimated an acceptable dosage (30-60 mg/kg), a performance statistically similar to that observed in African populations. Reproducing the present pole in the form of a strip of paper and including it in each container of praziquantel would greatly facilitate the administration of the drug in large-scale interventions.

Low-dose daily iron supplementation for 12 months does not increase the prevalence of malarial infection or density of parasites in young Zanzibari children

Conflicting evidence exists on the possible role of iron supplementation in the predisposition to malaria infection or the enhancement of its clinical severity. Where anemia prevalence is >40%, current guidelines are to provide low-dose daily iron to young children for up to 18 mo. Earlier studies used doses higher than the current guidelines, intermittent doses, or have supplemented for durations < or = 4 mo. We aimed to assess the effect of low-dose, long-term iron supplementation on malaria infection using a double-blind, placebo-controlled, randomized design, and to examine possible subgroup effects by season and child age. The study was conducted in Pemba Island, Zanzibar, where Plasmodium falciparum malaria has year-round high transmission. A community-based sample of 614 children 4-71 mo old was randomly allocated to 10 mg/d iron or placebo for 12 mo. Outcome measures were the prevalence and density of malaria infection, which was assessed by blood films at monthly intervals. At baseline, 94.4% were anemic (hemoglobin < 110 g/L), 48.1% were stunted (height-for-age Z-score less than -2) and >80% had malaria-positive blood films. No significant differences in malariometric indices were observed between children in the iron-supplemented and placebo groups. Parasite density was higher in certain months and in younger children, but iron supplementation was not associated with any malarial infection outcome in any season or age subgroup. We conclude that in this environment of high malaria transmission, daily oral low-dose supplementation of iron for 12 mo did not affect the prevalence of malaria infection or parasite density.

Soil-transmitted helminthiasis in Myanmar and approximate costs for countrywide control

Previous surveys in Myanmar indicate that soil-transmitted helminths (STH) are a significant public health problem. However the majority of these surveys are small scale or hospital based. To date there has been no countrywide assessment of the prevalence and intensity of STH infection. We conducted a survey (June 2002-June 2003) to assess the magnitude of STH infection in school age children in each of the different ecological areas of the country. In each area, five schools were selected and from each one, 50 children were randomly chosen. Parasitological and nutritional data were collected from each child. We found an overall prevalence of infection of 69%: 18% had a moderate-heavy intensity of infection, 22% were anaemic. A pilot exercise to treat 25,000 school age children in the 200 schools of Nyangdone Township tested the strategy before scaling up and to generate some rough costings. A crude calculation of the expenditure to buy and deliver the drugs, including the costs incurred in the teacher training, concluded that the cost per child was approximately 0.05 USD.

Progress in the prevention and control of schistosomiasis and soil-transmitted helminthiasis

In the last two decades important progress has been made in the understanding the epidemiology and the disease burden of schistosomiasis and soil-transmitted nematodes infection. In addition, practical tools for disease control have been developed and a strategy for the prevention and control of morbidy of schistosomaisis and soil-transmitted nematodes infection has been endorsed by the World Health Organization. This paper presents the recent progress in the prevention and control of these infections: the estimates of chronic and subtle morbidity in high risk groups and the evidence that these chronic and severe sequelae of infections can be reversed by appropriate treatment; the use of anthelminthic drugs during pregnancy and lactation; the relevance to control morbidity due to these infections also in pre-school children; the efficacy of anthelminthic drugs and the possible threat of drug resistance; price, quality and accessibility of treatment by delivering drugs through the school system and ways of reaching also non-enrolled school-age children. Finally, the strategy, targets and recommendations of the World Health Organization for the control of schistosomiasis and soil-transmitted nematodes infection are described.

Low dose daily iron supplementation improves iron status and appetite but not anemia, whereas quarterly anthelminthic treatment improves growth, appetite and anemia in Zanzibari preschool children

Iron deficiency and helminth infections are two common conditions of children in developing countries. The consequences of helminth infection in young children are not well described, and the efficacy of low dose iron supplementation is not well documented in malaria-endemic settings. A 12-mo randomized, placebo controlled, double-blind trial of 10 mg daily iron and/or mebendazole (500 mg) every 3 mo was conducted in a community-based sample of 459 Zanzibari children age 6-71 mo with hemoglobin > 70 g/L at baseline. The trial was designed to examine treatment effects on growth, anemia and appetite in two age subgroups. Iron did not affect growth retardation, hemoglobin concentration or mild or moderate anemia (hemoglobin < 110 g/L or < 90 g/L, respectively), but iron significantly improved serum ferritin and erythrocyte protoporphyrin. Mebendazole significantly reduced wasting malnutrition. but only in children <30 mo old. The adjusted odds ratios (AORs) for mebendazole in this age group were 0.38 (95% CI: 0.16, 0.90) for weight-for-height less than -1 Z-score and 0.29 (0.09, 0.91) for small arm circumference. In children <24 mo old, mebendazole also reduced moderate anemia (AOR: 0.41, 0.18, 0.94). Both iron and mebendazole improved children's appetite, according to mothers' report. In this study, iron's effect on anemia was limited, likely constrained by infection, inflammation and perhaps other nutrient deficiencies. Mebendazole treatment caused unexpected and significant reductions in wasting malnutrition and anemia in very young children with light infections. We hypothesize that incident helminth infections may stimulate inflammatory immune responses in young children, with deleterious effects on protein metabolism and erythropoiesis.

Hyperendemic fascioliasis associated with schistosomiasis in villages in the Nile Delta of Egypt

Coprologic surveys were carried out in villages of the Behera Governorate in the Nile Delta region of Egypt to characterize the epidemiologic features of human fascioliasis caused by Fasciola hepatica and F. gigantica in this lowland endemic area by comparison with fascioliasis caused by only F. hepatica in areas hyperendemic for human disease in the Andean highlands of South America. The fascioliasis prevalences detected (range = 5.2-19.0%, mean = 12.8%) are the highest obtained in Egypt. The comparison with previous results suggests that in the Nile Delta, fascioliasis is spreading from an original situation of sporadic human cases in well-known endemic foci for animal disease to an endemic distribution in humans, which may be characterized as a mesoendemic region that includes several hyperendemic areas for human disease. As in Andean countries, a relationship with sex was found, although in Egypt prevalences, but not intensities, appeared to be significantly higher in females. All ages appear to be susceptible to liver fluke infection, with prevalences and intensities being lower before and after school age, a situation that is consistent with that detected in Andean countries, although the peak in the 9-11-year-old age group appears less pronounced in Egypt. The intensities were very high when compared with those found in subjects sporadically infected in areas endemic for animal disease, but relatively low for a hyperendemic situation, although the intensities may not be conclusive because of the transmission seasonality of fascioliasis in the Nile Delta. The marked similarities in the qualitative and quantitative spectrums of protozoans and helminths, multiparasitisms, and associations between liver flukes and other parasitic species suggest physiographic-hydrographic and behavioral-social characteristics similar in all areas hyperendemic for human fascioliasis, which are independent of other factors such as climate, altitude, and cultural or religious features. The significant positive association between liver fluke infection and schistosomiasis mansoni detected in one locality has never been described elsewhere, and must be considered relevant from clinical, pathologic, diagnostic, and therapeutic points of view. Interestingly, the relationships of schistosomiasis prevalences and intensities with sex and age follow patterns similar to those found in fascioliasis.

Helminthic infections

Parasitic worms have largely been overlooked by medicine, but attitudes are changing with the realisation that they can seriously affect child development and that treatment is easy and cheap

Performance of the Haemoglobin Colour Scale in diagnosing severe and very severe anaemia

OBJECTIVE

To assess the accuracy of Haemoglobin Colour Scale (HCS) in identifying severely anaemic [haemoglobin (Hb) <7 g/dl] and very severely anaemic (Hb <5 g/dl) individuals, and to compare the performances of a group of health workers using HCS after training with a standard method.

METHOD

The study consisted of two parts. In part 1, the performance of HCS was compared with clinical examination in a hospital population of which more than 450 individuals were severely anaemic and more than 120 very severely anaemic. Part 2 of the study was conducted in eight dispensaries where the performances of 13 health workers using the colour scale were compared with the performances of eight other health workers using clinical signs to estimate Hb.

RESULTS

The colour scale was 92% sensitive for both severe anaemia and very severe anaemia and performed better than clinical examination. Health workers who used the colour scale did better in identifying anaemic and severely anaemic individuals, than those who used clinical examination.

CONCLUSIONS

The colour scale improves health workers' capacity to identify severely anaemic individuals and could be used as a basis for referral. Although the diagnostic accuracy of the workers using HCS varied widely, in most cases they did significantly better than those who used clinical investigation alone.

The control of human (neuro)cysticercosis: which way forward?

Taenia solium cysticercosis, and its public health and economic consequences, appears to be a growing problem in poor areas of Africa, Asia and Latin America where people eat pork and traditional pig husbandry is practiced (and expanding). Its burden is counted in terms of human disease (mainly neurocysticercosis related epilepsy) and economic losses, in a context of both commercial and traditional subsistence pig farming. Although substantial fragmentary information seems to be available from local settings, national and global burdens due to T. solium cysticercosis are still to be comprehensively assessed. With regard to control, several strategies have been checked out at a small or medium scale and have proven to be successful. Yet, no intervention programmes have been implemented so far at the national level with proven success. Although T. solium cysticercosis is considered to be a potentially eradicable disease, there is no evidence yet that it is feasible and recommendable to envisage this within a reasonable time frame. However, it appears realistic to aim for the rapid definition of a simple package of interventions, which can routinely be carried out by existing services and structures, and will give an optimal, long-term return in terms of burden relief. Also, a number of international initiatives and opportunities currently exist in which a more pro-active attitude towards the control of T. solium cysticercosis can be integrated and promoted. Commitment of both national and local authorities to control the disease needs to be convincingly solicited and, as for most zoonotic diseases, an interdisciplinary approach is essential.

The School Health Programme in Behera: an integrated helminth control programme at Governorate level in Egypt

School Health Programmes offer the opportunity to deliver public health interventions to a great number of beneficiaries at a relatively low cost and are seen with growing interest by policy makers in developing countries and the donors' communities. In Egypt a pilot School Health Programme has been implemented for the past 6 years in Behera, the largest and most populous Governorate of the Nile Delta. The Programme integrated additional activities for the control of soil-transmitted helminthiasis, human fascioliasis and anaemia in the National Schistosomiasis Control Programme (NSCP), implemented in Egypt since 1988 by the Ministry of Health and Population (MoHP). To facilitate planning and direct actions, a strong monitoring system was also developed, that generated useful information for the schistosomiasis control programme. The practical steps adopted to develop the programme are presented and discussed. Results from three rounds of monitoring (2000, 2001, 2002) are analysed and compared with baseline data conducted in 1996, together with the cost of each activity. On the basis of the experience gained by the Behera School Health Programme a number of operational recommendations are formulated.

Clinical signs and household characteristics associated with human fascioliasis among rural population in Egypt: a case-control study

The symptomatology associated with human fascioliasis has been studied mostly in hospitalised subjects. Very little is known about clinical signs and symptoms associated with infections in human endemic zones, as well as on possible new ways of transmission which might be responsible for the increased number of human cases reported in recent years. This information is of great importance to facilitate diagnosis and plan effective control measures. With the objective to identify clinical signs, blood tests, household characteristics and hygienic habits associated with human fascioliasis, a cross-sectional case-control study was implemented among the rural population of three endemic foci in the Nile Delta, Egypt. Clinical history was collected from 53 cases of fascioliasis and the same number of individually matched controls. They received a complete clinical examination and a range of blood tests was performed on them. Information on socio-economic conditions, dietary and hygienic habits was also collected. The most important complaints, associated with the infection, were right abdominal pain (Odds Ratio 20, P = 0.005), epigastric burning (o.r. 16, P = 0.007) and nausea (o.r. 8, P = 0.05). Blood analyses reported a marked increase in blood eosinophils (o.r 1.3, P = 0.001) among cases. The presence of cows (o.r 3.2), buffaloes (o.r 3.0) and goats (o.r 2.6) in the household was closely associated with the infection together with the habit to bring those animals to the canal for bathing and/or drinking (o.r. 3.2). Among dietary habits investigated, eating raw seeds was more common in cases than controls (o.r. 9, P = 0.03) and emerged as a possible new way of infection.

Efficacy of mebendazole and levamisole alone or in combination against intestinal nematode infections after repeated targeted mebendazole treatment in Zanzibar

OBJECTIVE

To evaluate the efficacy of and resistance to mebendazole (500 mg) and levamisole (40 or 80 mg), alone or in combination, for the treatment of Ascaris lumbricoides, Trichuris trichiura and hookworm infections on Pemba Island - an area exposed to periodic school-based mebendazole treatment since 1994.

METHODS

A randomized, placebo-controlled trial was carried out in 914 children enrolled from the first and fifth grades of primary schools. Stool samples collected at baseline and 21 days after treatment were examined by the Kato-Katz technique to assess the prevalence and intensity of helminth infection.

FINDINGS

Efficacies of mebendazole and levamisole as single treatments against intestinal nematode infections were comparable with those in previous trials, but mebendazole treatment of hookworm infections gave significantly lower cure (7.6%) and egg reduction (52.1%) rates than reported in a study undertaken before the beginning of periodic chemotherapy (cure rate, 22.4%; egg reduction rate, 82.4%). Combined treatment with mebendazole and levamisole had a significantly higher efficacy against hookworm infections (cure rate, 26.1%; egg reduction rate, 88.7%) than either drug given alone. No difference in mebendazole efficacy was found in children who had been treated repeatedly compared with those who had not been treated previously.

CONCLUSION

The overall efficacy of mebendazole against hookworm infections after periodic chemotherapy is reduced. The efficacy of benzimidazoles in chemotherapy-based control programmes should be monitored closely. Combined treatment with mebendazole and levamisole may be useful as a tool to delay the development of benzimidazole resistance.

Evaluation of the efficacy of pyrantel-oxantel for the treatment of soil-transmitted nematode infections

A randomized controlled trial comparing the efficacy of pyrantel-oxantel (10 mg/kg) with mebendazole (500 mg) was performed on 1329 schoolchildren aged 6-9 years on Pemba Island in September-October 2000 to evaluate alternative single-dose drugs for regular treatment of intestinal nematode infections. Both mebendazole and pyrantel-oxantel were very effective in eliminating Ascaris lumbricoides infection, inducing cure rates of more than 96% and reducing the mean egg counts by more than 95%. Both drugs had a moderate efficacy against Trichuris trichiura infection, but pyrantel-oxantel had a higher cure rate (31.5% vs. 23.3%, P < 0.01), though the reductions in egg counts did not differ significantly and were more than 80%. Pyrantel-oxantel and mebendazole had a similar, poor efficacy in curing hookworm infections and had a moderate effect in reducing the egg counts by 67% and 68%, respectively. Pyrantel-oxantel (10 mg/kg) offers a valuable alternative to mebendazole as a single-dose treatment for the control of intestinal nematode infections in children in endemic areas of sub-Saharan Africa, due to its comparable efficacy, its low cost and its suitability for use in young children.

Soil-transmitted nematode infections and mebendazole treatment in Mafia Island schoolchildren

In August 2000, a cross-sectional study was performed to assess the prevalence and intensity of soil-transmitted nematode infections in schoolchildren on Mafia Island. Hookworm infection was widespread (72.5% prevalence) whereas Trichuris trichiura was less prevalent (39.7%) and Ascaris lumbricoides was present at a low prevalence (4.2%), mainly in urban areas. In a subsample of the study population, both Necator americanus and Ancylostoma duodenale were found, although N. americanus was more prevalent. This survey was followed by a parasitological evaluation of mebendazole treatment using a single, 500-mg dose. The data on outcome were used for comparison with those from recent studies of similar treatment regimens in the neighbouring island of Pemba, Zanzibar, where periodic chemotherapy with mebendazole to schoolchildren has been implemented as part of a helminth-control programme since 1994. A higher efficacy of mebendazole against hookworm infection was found in Mafia Island (where a cure 'rate' of 31.3% and an egg-reduction 'rate' of 78.1% were recorded) when compared with that observed in Pemba Island, possibly indicating that hookworms may be developing mebendazole resistance on Pemba Island as a result of intense exposure to the drug there.

The global epidemiological situation of schistosomiasis and new approaches to control and research

While the distribution of schistosomiasis has changed over the last 50 years and there have been successful control programmes, the number of people estimated to be infected or at risk of infection has not been reduced. Today, 85% of the number of infected people are estimated to be on the African continent where few control efforts are made. In terms of disease burden, there is therefore a growing discrepancy between sub-Saharan Africa and the rest of the world. WHO has now developed a dual strategy for the control of schistosomiasis: a strategy for morbidity control adapted to the public health context in high burden areas, and a strategy to consolidate control in areas where a low endemic level has been reached and elimination may be feasible. Related to this new vision, some research needs are pointed out.

Field test of the 'dose pole' for praziquantel in Zanzibar

A graduated pole for height measurement, estimating the number of praziquantel tablets needed for treatment, was field-tested on 1289 children in Zanzibar. A bathroom-type scale performed better than the dose pole in delivering the optimal dose (40-60 mg/kg) and the 2 methods performed similarly in delivering a dose considered appropriate (30-60 mg/kg).

Is the exclusion of children under 24 months from anthelmintic treatment justifiable?

There are no reports documenting toxicity or adverse effects after treatment of children aged < 24 months with benzimidazole derivatives and there is an urgent need to clarify this point in light of the potential detrimental effect that soil-transmitted helminthiasis has on this age-group. A total of 653 treatments (317 mebendazole 500 mg; 336 placebo) were administered in 1996/97 to 212 children aged < 24 months as part of a 1-year anthelmintic drug study conducted among preschool-age children in Tanzania. Data on fever, cough, diarrhoea, dysentery and acute respiratory illness were collected 1 week following the treatment. No differences between the occurrence of adverse effects in the 2 groups were observed. In light of the potential nutritional benefit achieved by regular deworming in this young age-group, the policy that excludes children aged < 24 months from treatment should be re-considered.