Hand hygiene intervention to optimize helminth infection control: Design and baseline results of Mikono Safi-An ongoing school-based cluster-randomised controlled trial in NW Tanzania.

INTRODUCTION: Soil transmitted helminths (STH) can affect over 50% of children in some parts of Tanzania. Control measures involve annual deworming campaigns in schools, but re-infection is rapid. This paper presents the design and baseline survey results of an ongoing school-based cluster-randomised controlled trial in Kagera region, NW Tanzania. The trial aims to determine whether the effect of routine deworming on the prevalence of Ascaris lumbricoides and Trichuris trichiura infections among school aged children can be sustained when combined with a behaviour change intervention promoting handwashing with water and soap. METHODS: As part of the trial, a total of 16 schools were randomised to receive the intervention (N = 8) or as controls (N = 8). Randomisation was stratified per district and restricted to ensure pre-trial STH prevalence was balanced between study arms. The combination intervention to be tested comprises class-room based teacher-led health education, improvement of handwash stations, coloured nudges to facilitate handwashing and parental engagement sessions. The impact evaluation involves two cross-sectional surveys conducted at baseline and endline. The objectives of the baseline survey were: (i) to confirm whether the deworming campaign was successful, and identify and treat students still infected about 2 weeks after deworming, (ii) to document any baseline differences in STH prevalence between trial arms, and (iii) to assess handwashing behaviours, and access to water and sanitation at school and home. We randomly sampled 35 students per class in Grades 1-6 (an average of 200 children per school), stratified to ensure equal representation between genders. Assenting students were interviewed using a structured questionnaire and asked to provide a stool specimen. RESULTS: Results of the baseline survey conducted about 2 weeks after deworming shows balanced demographic and STH prevalence data across trial arms. We observed a low prevalence of ascariasis (< 5%) as expected; however, the prevalence of trichuriasis was still about 35% in both arms. CONCLUSION: The randomisation procedure was successful in achieving a balanced distribution of demographic characteristics and helminth infections between trial arms. The intervention is being rolled out. The current deworming treatment regimen may need to be revised with regards to the treatment of trichuriasis.

Assessment of schistosomiasis and soil-transmitted helminths prevalence in school-aged children and opportunities for integration of control in local health services in Kwilu Province, the Democratic Republic of the Congo.

OBJECTIVE: To determine the prevalence of schistosomiasis (SCH) and soil-transmitted helminths (STH) in the Democratic Republic of Congo, and to assess the capacity of the local health centres for diagnosis and treatment. METHODS: Cross-sectional school-based survey in two health districts in the Province of Kwilu. We collected a stool and a urine sample for parasitological examination. Urine filtration and duplicate Kato-Katz thick smears were used for the diagnosis of SCH. Health centres were evaluated using a structured questionnaire. RESULTS: In total, 526 children participated in the study and the overall prevalence of Schistosoma mansoni infection was 8.9% (95% CI: 3.5-13.2) in both districts. The prevalence was higher in Mosango (11.7%; 95% CI: 8.9-14.8) than Yasa Bonga district (6.2%; 95% CI: 1.1-11.4). Urine filtration showed that Schistosoma haematobium infection was not present. The combined STH infection prevalence was 58.1% in both districts; hookworm infection was the most common STH found in 52.9% (95% CI: 29.3-62.4) of subjects, followed by Ascaris lumbricoides 9.3% (95% CI: 5.8-15.5) and Trichuris trichiura 2.1% (95% CI: 0.9-4.9). Mixed STH infections were observed as well as SCH-STH coinfection. CONCLUSION: Further mapping of both SCH and STH burden is needed, and coverage of preventive chemotherapy in school-aged children should be increased.

Complexities and Perplexities: A Critical Appraisal of the Evidence for Soil-Transmitted Helminth Infection-Related Morbidity.

BACKGROUND: Soil-transmitted helminths (STH) have acute and chronic manifestations, and can result in lifetime morbidity. Disease burden is difficult to quantify, yet quantitative evidence is required to justify large-scale deworming programmes. A recent Cochrane systematic review, which influences Global Burden of Disease (GBD) estimates for STH, has again called into question the evidence for deworming benefit on morbidity due to STH. In this narrative review, we investigate in detail what the shortfalls in evidence are. METHODOLOGY/PRINCIPAL FINDINGS: We systematically reviewed recent literature that used direct measures to investigate morbidity from STH and we critically appraised systematic reviews, particularly the most recent Cochrane systematic review investigating deworming impact on morbidity. We included six systematic reviews and meta-analyses, 36 literature reviews, 44 experimental or observational studies, and five case series. We highlight where evidence is insufficient and where research needs to be directed to strengthen morbidity evidence, ideally to prove benefits of deworming. CONCLUSIONS/SIGNIFICANCE: Overall, the Cochrane systematic review and recent studies indicate major shortfalls in evidence for direct morbidity. However, it is questionable whether the systematic review methodology should be applied to STH due to heterogeneity of the prevalence of different species in each setting. Urgent investment in studies powered to detect direct morbidity effects due to STH is required.

Worm Infections in Children.

• On the basis of research evidence, worm infections are important global child health conditions causing chronic disability that lasts from childhood into adulthood (Table 1). (2)(3) Evidence Quality: B • On the basis of research evidence, the major worm infections found in developing countries include ascariasis, trichuriasis, hookworm infection, and schistosomiasis; toxocariasis, enterobiasis, and cysticercosis are also found in poor regions of North America and Europe. (4)(9)(13) Evidence Quality: B • On the basis of expert consensus, children and adolescents are often vulnerable to acquiring large numbers of worms, ie, high-intensity infections (Fig 1)(21)(22)(23) Evidence Quality: D • On the basis of expert consensus and research evidence, moderate and heavy worm burdens cause increased morbidity because of growth and intellectual stunting in children and adolescents. Many of these effects may result from helminth-induced malnutrition. (21)(22)(23) Evidence Quality: C • On the basis of expert consensus and research evidence, worm infections are also commonly associated with eosinophilia. (48) (49) Evidence Quality: B • On the basis of research evidence as well as consensus, helminthes can cause inflammation in the lung (asthma), gastrointestinal tract (enteritis and colitis), liver (hepatitis and fibrosis), and urogenital tract. (7)(21)(22)(23)(27)(28)(40)(41)(43) Evidence Quality: B • On the basis of research evidence, microscopy techniques for diagnosis of worm infections in children often exhibit suboptimal sensitivities and specificities, necessitating new or improved diagnostic modalities such as polymerase chain reaction. (54)(55) Evidence Quality: A • On the basis of research evidence and expert consensus, mass drug administration ("preventive chemotherapy") has becomea standard practice for ministries of health in low- and middle-income countries to control intestinal helminth infections and schistosomiasis. (67)(68) Evidence Quality: B.

A quantitative assessment method for Ascaris eggs on hands.

The importance of hands in the transmission of soil transmitted helminths, especially Ascaris and Trichuris infections, is under-researched. This is partly because of the absence of a reliable method to quantify the number of eggs on hands. Therefore, the aim of this study was to develop a method to assess the number of Ascaris eggs on hands and determine the egg recovery rate of the method. Under laboratory conditions, hands were seeded with a known number of Ascaris eggs, air dried and washed in a plastic bag retaining the washing water, in order to determine recovery rates of eggs for four different detergents (cationic [benzethonium chloride 0.1% and cetylpyridinium chloride CPC 0.1%], anionic [7X 1% - quadrafos, glycol ether, and dioctyl sulfoccinate sodium salt] and non-ionic [Tween80 0.1% -polyethylene glycol sorbitan monooleate]) and two egg detection methods (McMaster technique and FLOTAC). A modified concentration McMaster technique showed the highest egg recovery rate from bags. Two of the four diluted detergents (benzethonium chloride 0.1% and 7X 1%) also showed a higher egg recovery rate and were then compared with de-ionized water for recovery of helminth eggs from hands. The highest recovery rate (95.6%) was achieved with a hand rinse performed with 7X 1%. Washing hands with de-ionized water resulted in an egg recovery rate of 82.7%. This washing method performed with a low concentration of detergent offers potential for quantitative investigation of contamination of hands with Ascaris eggs and of their role in human infection. Follow-up studies are needed that validate the hand washing method under field conditions, e.g. including people of different age, lower levels of contamination and various levels of hand cleanliness.

Incentive mechanisms for liver lesion control in finishing pigs in the Netherlands.

Liver lesion prevalence in slaughtered finishing pigs in the Netherlands remained relatively high from the mid-1990s until 2004, although sufficient measures existed to control the main cause, an infection with the roundworm Ascaris suum. In July 2004 a new incentive mechanism was installed to induce finishing pig producers to increase control of A. suum infections. This paper compares the effectiveness of two Dutch incentive mechanisms: a collective insurance - in place prior to July 2004 - and a reduction in producer payment for each delivered pig with a liver lesion - in place from July 2004. Liver inspection data of pigs slaughtered in 2003-2006 by a major Dutch slaughter company were analysed with an out-of-sample dynamic forecast test and non-parametric bootstrapping. Results showed that after introduction of the price reduction, mean liver lesion prevalence decreased from 9 to 5%. A reduced liver lesion prevalence ranging from 0 to 46 percentage points was observed on 67% of 1069 farms that delivered both during the insurance and the price reduction. The number of farms with a liver lesion prevalence of 5.0% or less increased from 52 to 68%. The price reduction for each pig with a liver lesion was a more effective incentive mechanism to induce finishing pig producers to control A. suum infections than the collective insurance.

Using national health weeks to deliver deworming to children: lessons from Mexico.

Mexico established national health weeks (NHWs) in the early 1980s to promote childhood vaccinations. Because of the cumulative worldwide peer-reviewed scientific evidence, the recommendations of the World Health Organization and other international organisations, the political will of the Mexican government and the infrastructure provided by the NHWs, deworming was added to the NHWs in 1993. In addition to the Ministry of Health, several other government organisations participated in administering the deworming component. Tens of millions of school-age and preschool children between the ages of 2 years and 14 years now receive deworming (a single 400 mg dose of albendazole) approximately every 8 months. Between 1993 and 1998 evaluations were carried out in over 90,000 children to determine the effect of NHWs on the prevalence of geohelminth infections. In 1993, the overall prevalence of Ascaris was 20% and that of Trichuris was 15%. Prevalences decreased significantly over time (p <0.001). Treatment efficacy for Ascaris ranged from 91.6% to 85.3%, and for Trichuris, from 97.9% to 42.6%. In 1998, after conducting 12 NHWs with deworming, the respective prevalences were Ascaris 8% and Trichuris 11%. The experience of Mexico in integrating albendazole into its NHWs shows how deworming can be delivered to large numbers of at-risk children using an existing infrastructure. The NHW approach may be generalisable in other countries with successful national vaccination campaigns. The challenge remaining is to sustain the deworming programme until other longer-term behavioural, environmental and socioeconomic changes can be implemented.

Financial costs of deworming children in all primary schools in Cambodia.

In 2002, Cambodia's Ministry of Health launched a deworming programme to deliver an anthelmintic drug (mebendazole 500 mg) and health education to 75% of its school children twice a year. Cambodia's school population is approximately 2.8 million. The deworming programme was organized into two phases: the first phase (December 2002-March 2003) targeted more than one million school children from 11 provinces; and the second phase (July 2003-January 2004) targeted the entire school population. The cost to treat each child was 12 cents (0.11 USD) during the first phase, 6 cents during the second phase, and 3 cents for re-treatment in areas where the campaign was conducted for the second time. The Cambodian experience demonstrates that, with political commitment, high coverage for deworming is achievable even in a country with minimal resources. Cambodia's deworming programme represents a successful model for other developing countries.

The public health importance of Ascaris lumbricoides.

Numerous studies have shown that anthelminthic treatment can be effective in improving growth rates when given to malnourished children with ascariasis. Recent investigations have also indicated that Ascaris infections can affect mental processing in some school children. Poor socio-economic conditions are among the key factors linked with higher prevalences of ascariasis, as are defaecation practices, geophagia, cultural differences relating to personal and food hygiene, occupational necessity, agricultural factors, housing style, social class and gender. Chemotherapy is currently the major tool used for the strategic control of ascariasis as a short-term goal. In the long term, improvements in hygiene and sanitation are thought to aid long-term control considerably. Targeted treatment, especially when aimed at schoolchildren, has been a major focus of recent control efforts in some areas. Universal treatment reaches more people and thus decreases further aggregate morbidity, especially in nutritionally vulnerable preschool-age children. Selective treatment requires technical effort to identify heavily infected individuals; acceptance by the community may vary in less educated populations when some individuals receive treatment and others do not. Child-targeted treatment may be more cost-effective than population treatment in reducing the number of disease cases and, in high transmission areas, expanding coverage of a population can be a more cost-effective strategy than increasing the frequency of treatment.

Assessment of combined ivermectin and albendazole for treatment of intestinal helminth and Wuchereria bancrofti infections in Haitian schoolchildren.

This randomized, placebo-controlled trial investigated the efficacy and nutritional benefit of combining chemotherapeutic treatment for intestinal helminths (albendazole) and lymphatic filariasis (ivermectin). Children were infected with Ascaris (29.2%), Trichuris (42.2%), and hookworm (6.9%), with 54.7% of children having one or more of these parasites. Wuchereria bancrofti microfilaria were found in 13.3% of the children. Children were randomly assigned to treatment with placebo, albendazole, ivermectin, or combined therapy. Combination treatment reduced the prevalence of Trichuris infections significantly more than either drug alone. Combination therapy also significantly reduced the prevalence and density of W. bancrofti microfilaremia compared with placebo or ivermectin alone. Only combination therapy resulted in significantly greater gains in height (hookworm-infected children) or weight (Trichuris-infected children) compared with the placebo group. Combined albendazole and ivermectin was a more efficacious treatment for intestinal helminth and W. bancrofti infections in children and resulted in nutritional benefits not found with either drug alone.

A study of the cost effectiveness of selective health interventions for the control of intestinal parasites in rural Bangladesh.

The study examined the cost effectiveness of 4 different regimens in reducing the prevalence and intensity of infection of Ascaris lumbricoides, Trichuris trichiura, and hookworm over an 18-mo period in randomized community samples of children aged 2-8 yr living in rural Bangladesh. The household was the unit of randomization in each community. The 4 regimens were (1) only chemotherapy to all household members at the commencement of the study (i.e., at an interval of 18 mo), (2) same as group (1) and regular health education throughout the study period, (3) chemotherapy to all household members at the commencement of the study and subsequent chemotherapy to all children at intervals of 6 mo, and (4) same as group 3 with the addition of regular health education throughout the study period. Health education (through home and school visits and focus group discussions) was aimed at increasing awareness of worm transmission and the disabilities caused by intestinal helminths. Simple ways of improving personal hygiene and sanitation through hand washing, nail trimming, wearing of shoes, and use of a latrine and clean water supplies were encouraged. Because albendazole is a broad spectrum anthelmintic, the cost effectiveness of the 4 interventions were compared by the weighted percentage reduction in prevalence and the weighted percentage reduction in intensities of infection as measured by geometric mean egg loads of all 3 worms combined. The most cost-effective strategy was the single albendazole mass chemotherapy at an interval of 18 mo. The 2 regimens involving health education were the least cost effective.

A cost-effectiveness analysis of anthelminthic intervention for community control of soil-transmitted helminth infection: levamisole and Ascaris lumbricoides.

A study to compare effects of mass, targeted, and selective chemotherapy with levamisole as an intervention for the control of Ascaris lumbricoides was carried out in 3 communities in rural Oyo State, Nigeria. Selective treatment was applied in 1 village by treating the most heavily infected 20% of the inhabitants, targeted treatment in the second village involved children aged 2-15 yr, whereas mass treatment was offered to all inhabitants in the third village, excluding infants under 1 yr and pregnant women. Intensity (eggs per gram,) of A. lumbricoides infection was determined immediately before and 3 mo after the period of intervention as a means of assessing the relative efficacy of the treatment regimes. During the field study, information on resource use was also collected for a retrospective cost analysis of the 3 strategies Resources used included manpower, materials, drugs, and transport. The results of the parasitological evaluation on the effect of treatment on egg intensity were then combined with the cost analysis to provide an overall measure of the cost-effectiveness of mass, targeted, and selective interventions. The results were expressed in terms of the cost per 1,000 egg reduction in intensity and the cost per person treated. The results showed the mass and targeted approach to be considerably more cost effective than the selective approach.

Control of Ascaris infection by chemotherapy: which is the most cost-effective option?

Cost-effectiveness analysis is used to predict the optimal design of mass chemotherapy strategies in controlling Ascaris lumbricoides infection. The question of who to treat, how many to treat, and how often to treat are addressed using a population dynamic model of helminth transmission that assesses effectiveness in terms of disease reduction, combined with cost data from an actual control programme. Child-targeted treatment can be more cost-effective than population treatment in reducing the number of disease cases. The model also implies that, in the circumstances described here, enhancing coverage is a more cost-effective approach than increasing frequency of treatment.

Helminth parasites, a major factor in malnutrition.

The author discusses the significance of helminth and schistosome infections in exacerbating nutritional problems in many countries, and advocates population-wide treatment where there is clear evidence that this would yield substantial gains in the quality of life.

PIP: Helminth and schistosome infections occur in the same geographical areas as does malnutrition. These parasitic infections can occur already in malnourished persons. Hookworm infections reduces food intake and/or increase nutrient wastage via vomiting, diarrhea, or blood loss. These effects exasperate protein energy malnutrition, anemia, and other nutrient deficiencies. Hookworm infection reduces the work capacity and productivity of children and adults; increases maternal and fetal morbidity, premature delivery, and low birth weight, as well as the susceptibility to other infections; and reduces the rate of cognitive development. These social and economic consequences in turn reduce the ability of people and families to raise crops or earn enough money to buy food and other essentials. As many as 90% of the children in some areas of the developed world are infected with roundworm. More than 100,000 deaths in 1987 resulted from complications of roundworm infection (e.g., intestinal obstruction). Roundworm infection reduces the body's ability to use protein and to absorb fat, which worsens protein energy malnutrition. Other nutrient effects of roundworm infection are exacerbation of vitamin A deficiency and lactose and milk intolerance. Whipworm infection can effect prolapse of the rectum and nutritional problems. Treatment of children with whipworm improves hematocrit, growth rates and anthropometry, and serum albumin, and reduces diarrhea and bacterial and protozoan infections in the bowel. Schistosomiasis causes nutritional effects similar to those of helminths. Studies in Kenya show that, in children, 1 treatment against worm, infections improves growth and fitness within 4 months. Other studies in Kenya show that treating children for worms or anemia improves weight gains per month at least as much as and usually more than school feeding programs, a more labor intensive, complicated, and expensive effort. Deworming programs should operate in areas where undernutrition exceeds 25% and worms are prevalent.

Assessment of the effectiveness of primary health care interventions in the control of three intestinal nematode infections in rural communities.

In a 30 months' longitudinal study, primary health care intervention was effective in reducing the prevalence of three common intestinal nematode infections (Ascaris lumbricoides, Trichuris trichiura and Necator americanus) in three communities. This was achieved by training school leavers and auxiliary aides as microscopists, health inspectors and field assistants and deploying them to provide screening, surveillance, environmental sanitation, and mass-expulsion chemotherapy (MEC). Post-control surveillance confirmed that the prevalence of these infections had been greatly reduced. The prevalence of Ascaris lumbricoides had declined from 49.3% (pre-intervention) to 10.5% (post-intervention). Hookworm had fallen from 31.4% (pre-intervention) to 4.1% (post-intervention) and whipworm from 40.7% (pre-intervention) to 6.5% (post-intervention). Overall percentage decreases of 78.7%, 86.9% and 84.0% were recorded for Ascaris lumbricoides, Necator americanus and Trichuris trichiura respectively. The initial decline in prevalence was due to the MEC campaign, but the improved sanitation and health education presumably reduced the reinfection rate. If the entire population participated, periodic repetition of the mass expulsion therapy campaign at appropriate intervals combined with continued attention to environmental hygiene and prolonged health education could bring these infections under control within a few years.

PIP: In the late 1980s and early 1990s in Nigeria, parasitologist evaluated the effectiveness of health education, environmental sanitation, and mass expulsion chemotherapy (MEC) in controlling endemic parasitic infections (Ascaris lumbricoides, Trichuris trichiura, and Necator americanus) in the population served by health care centers in Ndele, Emohua, and Aluu (in the eastern area of the Niger Delta Basin). 240 dropouts from primary and secondary schools and 45 auxiliary nurses from the communities underwent 6 months, training to become health inspectors, microscopists, field assistants, and surveillance staff. About 120 people/day frequented each community health education forum at the centers. The communities worked together to build ventilation-improved pit latrines, resulting in a considerable decline of open air defecation. 54.5% of the population provided stool samples so researchers could determine the prevalence of intestinal nematode infections. Health workers administered a single dose of either Alcopar or Zentel to all people diagnosed with nematode infection. The infected people also received nutritional supplements as required. Initial prevalence was 49.3% for A. lumbricoides, 40.7% for T. trichiura, and 31.4% g for N. americanus. The interventions contributed to a decline in overall prevalence ranging from 70.6% (A. lumbricoides in Ndele) to 88.2% (N. americanus in Emohua). The percentage of reduction of A. lumbricoides infection increased as age increased (e.g., 73.5% reduction for 5 year old children and 86% reduction for 45 to 54 year olds). Little difference in reduction with age existed for N. americanus and T. trichiura infections, however, 30 months after intervention prevalence was 10.5% for A. lumbricoides, 6.3% for T. trichiura, and 3.9% for N. americanus. These findings indicated that health education campaigns, MEC campaigns, and improvement in environmental sanitation result in considerable reduction of nematode infections.