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.