Environmental characteristics around the household and their association with hookworm infection in rural communities from Bahir Dar, Amhara Region, Ethiopia.

Soil-Transmitted Helminths (STH) are highly prevalent Neglected Tropical Disease in Ethiopia, an estimated 26 million are infected. Geographic Information Systems and Remote Sensing (RS) technologies assist data mapping and analysis, and the prediction of the spatial distribution of infection in relation to environmental variables. The influence of socioeconomic, environmental and soil characteristics on hookworm infection at the individual and household level is explored in order to identify spatial patterns of infection in rural villages from Zenzelema (Amhara region). Inhabitants greater than 5 years old were recruited in order to assess the presence of STH. Socioeconomic and hookworm infection variables at the household level and environmental variables and soil characteristics using RS were obtained. The dominant STH found was hookworm. Individuals which practiced open defecation and those without electricity had a significant higher number of hookworm eggs in their stool. Additionally, adults showed statistically higher hookworm egg counts than children. Nonetheless, the probability of hookworm infection was not determined by socioeconomic conditions but by environmental characteristics surrounding the households, including a combination of vigorous vegetation and bare soil, high temperatures, and compacted soils (high bulk density) with more acidic pH, given a pH of 6.0 is optimal for hatching of hookworm eggs. The identification of high-risk environmental areas provides a useful tool for planning, targeting and monitoring of control measures, including not only children but also adults when hookworm is concerned.

The Effect of Drug Pricing on Outpatient Payments and Treatment for Three Soil-Transmitted Helminth Infections in the United States, 2010-2017.

The price of certain antiparasitic drugs (e.g., albendazole and mebendazole) has dramatically increased since 2010. The effect of these rising prices on treatment costs and use of standard of care (SOC) drugs is unknown. To measure the impact of drug prices on overall outpatient cost and quality of care, we identified outpatient visits associated with ascariasis, hookworm, and trichuriasis infections from the 2010 to 2017 MarketScan Commercial Claims and Encounters and Multi-state Medicaid databases using Truven Health MarketScan Treatment Pathways. Evaluation was limited to members with continuous enrollment in non-capitated plans 30 days prior, and 90 days following, the first diagnosis. The utilization of SOC prescriptions was considered a marker for quality of care. The impact of drug price on the outpatient expenses was measured by comparing the changes in drug and nondrug outpatient payments per patient through Welch's two sample t-tests. The total outpatient payments per patient (drug and nondrug), for the three parasitic infections, increased between 2010 and 2017. The increase was driven primarily by prescription drug payments, which increased 20.6-137.0 times, as compared with nondrug outpatient payments, which increased 0.3-2.2 times. As prices of mebendazole and albendazole increased, a shift to alternative SOC and non-SOC drug utilization was observed. Using parasitic infection treatment as a model, increases in prescription drug prices can act as the primary driver of increasing outpatient care costs. Simultaneously, there was a shift to alternative SOC, but also to non-SOC drug treatment, suggesting a decrease in quality of care.

The Global Economic and Health Burden of Human Hookworm Infection.

BACKGROUND: Even though human hookworm infection is highly endemic in many countries throughout the world, its global economic and health impact is not well known. Without a better understanding of hookworm's economic burden worldwide, it is difficult for decision makers such as funders, policy makers, disease control officials, and intervention manufacturers to determine how much time, energy, and resources to invest in hookworm control. METHODOLOGY/PRINCIPLE FINDINGS: We developed a computational simulation model to estimate the economic and health burden of hookworm infection in every country, WHO region, and globally, in 2016 from the societal perspective. Globally, hookworm infection resulted in a total 2,126,280 DALYs using 2004 disability weight estimates and 4,087,803 DALYs using 2010 disability weight estimates (excluding cognitive impairment outcomes). Including cognitive impairment did not significantly increase DALYs worldwide. Total productivity losses varied with the probability of anemia and calculation method used, ranging from $7.5 billion to $138.9 billion annually using gross national income per capita as a proxy for annual wages and ranging from $2.5 billion to $43.9 billion using minimum wage as a proxy for annual wages. CONCLUSION: Even though hookworm is classified as a neglected tropical disease, its economic and health burden exceeded published estimates for a number of diseases that have received comparatively more attention than hookworm such as rotavirus. Additionally, certain large countries that are transitioning to higher income countries such as Brazil and China, still face considerable hookworm burden.

Economic Analysis of the Impact of Overseas and Domestic Treatment and Screening Options for Intestinal Helminth Infection among US-Bound Refugees from Asia.

BACKGROUND: Many U.S.-bound refugees travel from countries where intestinal parasites (hookworm, Trichuris trichuria, Ascaris lumbricoides, and Strongyloides stercoralis) are endemic. These infections are rare in the United States and may be underdiagnosed or misdiagnosed, leading to potentially serious consequences. This evaluation examined the costs and benefits of combinations of overseas presumptive treatment of parasitic diseases vs. domestic screening/treating vs. no program. METHODS: An economic decision tree model terminating in Markov processes was developed to estimate the cost and health impacts of four interventions on an annual cohort of 27,700 U.S.-bound Asian refugees: 1) "No Program," 2) U.S. "Domestic Screening and Treatment," 3) "Overseas Albendazole and Ivermectin" presumptive treatment, and 4) "Overseas Albendazole and Domestic Screening for Strongyloides". Markov transition state models were used to estimate long-term effects of parasitic infections. Health outcome measures (four parasites) included outpatient cases, hospitalizations, deaths, life years, and quality-adjusted life years (QALYs). RESULTS: The "No Program" option is the least expensive ($165,923 per cohort) and least effective option (145 outpatient cases, 4.0 hospitalizations, and 0.67 deaths discounted over a 60-year period for a one-year cohort). The "Overseas Albendazole and Ivermectin" option ($418,824) is less expensive than "Domestic Screening and Treatment" ($3,832,572) or "Overseas Albendazole and Domestic Screening for Strongyloides" ($2,182,483). According to the model outcomes, the most effective treatment option is "Overseas Albendazole and Ivermectin," which reduces outpatient cases, deaths and hospitalization by around 80% at an estimated net cost of $458,718 per death averted, or $2,219/$24,036 per QALY/life year gained relative to "No Program". DISCUSSION: Overseas presumptive treatment for U.S.-bound refugees is a cost-effective intervention that is less expensive and at least as effective as domestic screening and treatment programs. The addition of ivermectin to albendazole reduces the prevalence of chronic strongyloidiasis and the probability of rare, but potentially fatal, disseminated strongyloidiasis.

Rates and intensity of re-infection with human helminths after treatment and the influence of individual, household, and environmental factors in a Brazilian community.

This study quantifies the rate and intensity of re-infection with human hookworm and Schistosoma mansoni infection 12 months following successful treatment, and investigates the influence of socio-economic, geographical and environmental factors. A longitudinal study of 642 individuals aged over 5 years was conducted in Minas Gerais State, Brazil from June 2004 to March 2006. Risk factors were assessed using interval censored regression for the rate and negative binomial regression for intensity. The crude rate and intensity of hookworm re-infection was 0·21 per year (95% confidence interval (CI) 0·15-0·29) and 70·9 epg (95% CI 47·2-106·6). For S. mansoni the rate was 0·06 per year (95% CI 0·03-0·10) and intensity 6·51 epg (95% CI 3·82-11·11). Rate and intensity of re-infection with hookworm were highest among males and positively associated with previous infection status, absence of a toilet and house structure. Rate and intensity of S. mansoni re-infection were associated with previous infection status as well as geographical, environmental and socio-economic factors. The implications of findings for the design of anti-helminth vaccine trials are discussed.

The potential economic value of a hookworm vaccine.

Hookworm infection is a significant problem worldwide. As development of hookworm vaccine proceeds, it is essential for vaccine developers and manufacturers, policy makers, and other public health officials to understand the potential costs and benefits of such a vaccine. We developed a decision analytic model to evaluate the cost-effectiveness of introducing a hookworm vaccine into two populations in Brazil: school-age children and non-pregnant women of reproductive age. Results suggest that a vaccine would provide not only cost savings, but potential health benefits to both populations. In fact, the most cost-effective intervention strategy may be to combine vaccine with current drug treatment strategies.

Economic Effects of Childhood Exposure To Tropical Disease.

To what extent do tropical diseases contribute to the poverty characteristic of tropical countries? Estimates of the impact of health on income are difficult to obtain because health is a normal good-countries with higher income will buy more of it-and third factors such as remoteness and bad government might impede both productivity and public health. In the Abuja Declaration of 2005, African heads of states claim that malaria has depressed income growth in Subsaharan Africa since the 1960s, so much so that GDP in the region today is 40% lower because of malaria. Estimates of this magnitude have been mocked at cocktail parties and clambakes. But how ridiculous is this number?

The neglected tropical diseases of Latin America and the Caribbean: a review of disease burden and distribution and a roadmap for control and elimination.

The neglected tropical diseases (NTDs) represent some of the most common infections of the poorest people living in the Latin American and Caribbean region (LAC). Because they primarily afflict the disenfranchised poor as well as selected indigenous populations and people of African descent, the NTDs in LAC are largely forgotten diseases even though their collective disease burden may exceed better known conditions such as of HIV/AIDS, tuberculosis, or malaria. Based on their prevalence and healthy life years lost from disability, hookworm infection, other soil-transmitted helminth infections, and Chagas disease are the most important NTDs in LAC, followed by dengue, schistosomiasis, leishmaniasis, trachoma, leprosy, and lymphatic filariasis. On the other hand, for some important NTDs, such as leptospirosis and cysticercosis, complete disease burden estimates are not available. The NTDs in LAC geographically concentrate in 11 different sub-regions, each with a distinctive human and environmental ecology. In the coming years, schistosomiasis could be eliminated in the Caribbean and transmission of lymphatic filariasis and onchocerciasis could be eliminated in Latin America. However, the highest disease burden NTDs, such as Chagas disease, soil-transmitted helminth infections, and hookworm and schistosomiasis co-infections, may first require scale-up of existing resources or the development of new control tools in order to achieve control or elimination. Ultimately, the roadmap for the control and elimination of the more widespread NTDs will require an inter-sectoral approach that bridges public health, social services, and environmental interventions.

Hookworm and poverty.

Human hookworm infection is the leading cause of anemia and undernutrition and the second most important parasitic infection of humans. Hookworm occurs almost exclusively in the setting of rural poverty in the developing countries of the tropics. The rural dependency reflects the precise soil and temperature requirements of the environmental life history stages of the parasite, whereas the relationship between hookworm and poverty is based on multiple factors, including inadequate sanitation, the absence of concrete floors in home dwellings, and lack of access to essential medicines. Also, hookworm not only occurs in the setting of poverty but also promotes poverty because of its health and educational effects in children, its adverse effect on pregnancy outcome, and its effect on worker productivity. Since the middle of the 20th century, poverty reduction and urbanization have successfully reduced the prevalence of hookworm in the world's industrialized nations and some middle-income countries. However, the control of hookworm in low-income countries still relies heavily on the frequent and periodic use of anthelminthic drugs either through deworming programs targeting school-aged children or through integrated control programs that simultaneously target the seven neglected tropical diseases, including hookworm. However, the high rates of hookworm reinfection and the possible emergence of drug resistance will ultimately require the development of new control tools--including the Human Hookworm Vaccine, one of several so-called antipoverty vaccines that could undergo development and testing over the next decade.

Intestinal helminth infections, anaemia and labour productivity of female tea pluckers in Bangladesh.

We conducted a randomized clinical intervention trial over 24 weeks on a tea estate in north-east Bangladesh to investigate the effect of iron supplementation and anthelmintic treatment on the labour productivity of adult female tea pluckers. A total of 553 full-time tea pluckers, not pregnant and not breastfeeding, were randomly assigned to one of the four intervention groups: group 1 received iron supplementation on a weekly basis, group 2 received anthelmintic treatment at the beginning and half-way through the trial (week 12), group 3 received both iron supplementation as group 1 and anthelmintic treatment as group 2, and group 4 was a control group and received placebos. No significant difference in labour productivity was found between the four intervention groups over the trial period. However, there was a negative association for all three worms (Ascaris lumbricoides, Trichuris trichiura and hookworms) between the intensity of helminth infections (eggs/g faeces) and all measures of labour productivity. Lower haemoglobin values and anaemia (< 120 g/l Hb) were both associated with lower labour productivity and more days sick and absent. Taller women with greater arm circumference were able to pluck more green leaves, earn higher wages and were absent less often.

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.