Current epidemiological trends for Chagas disease in Latin America and future challenges in epidemiology, surveillance and health policy

Chagas disease, named after Carlos Chagas, who first described it in 1909, exists only on the American Continent. It is caused by a parasite, Trypanosoma cruzi, which is transmitted to humans by blood-sucking triatomine bugs and via blood transfusion. Chagas disease has two successive phases: acute and chronic. The acute phase lasts six-eight weeks. Several years after entering the chronic phase, 20-35% of infected individuals, depending on the geographical area, will develop irreversible lesions of the autonomous nervous system in the heart, oesophagus and colon, and of the peripheral nervous system. Data on the prevalence and distribution of Chagas disease improved in quality during the 1980s as a result of the demographically representative cross-sectional studies in countries where accurate information was not previously available. A group of experts met in Brasilia in 1979 and devised standard protocols to carry out countrywide prevalence studies on human T. cruzi infection and triatomine house infestation. Thanks to a coordinated multi-country programme in the Southern Cone countries, the transmission of Chagas disease by vectors and via blood transfusion was interrupted in Uruguay in 1997, in Chile in 1999 and in Brazil in 2006; thus, the incidence of new infections by T. cruzi across the South American continent has decreased by 70 percent. Similar multi-country initiatives have been launched in the Andean countries and in Central America and rapid progress has been reported towards the goal of interrupting the transmission of Chagas disease, as requested by a 1998 Resolution of the World Health Assembly. The cost-benefit analysis of investment in the vector control programme in Brazil indicates that there are savings of US$17 in medical care and disabilities for each dollar spent on prevention, showing that the programme is a health investment with very high return. Many well-known research institutions in Latin America...

Insect vectors of Leishmania: distribution, physiology and their control.

Leishmaniasis is a deadly vector-borne disease that causes significant morbidity and mortality in Africa, Asia, Latin America and Mediterranean regions. The causative agent of leishmaniasis is transmitted from man to man by a tiny insect called sandfly. Approximately, 600 species of sandflies are known but only 10% of these act as disease vectors. Further, only 30 species of these are important from public health point. Fauna of Indian sub-zone is represented by 46 species, of these, 11 belong to Phlebotomine species and 35 to Sergentomyia species. Phlebotomus argentipes is the proven vector of kala-azar or visceral leishmaniasis in India. This review gives an insight into the insect vectors of human leishmaniasis, their geographical distribution, recent taxonomic classification, habitat, and different control measures including indoor residual spraying (IRS), insecticide-treated bednets (ITNs), environmental management, biological control, and emerging resistance to DDT. Role of satellite remote sensing for early prediction of the disease by identifying the sandflygenic conditions cannot be undermined. The article also underlines the importance of synthetic pheromones which can be used in near future for the control of these vectors.

Estudio de costo/beneficio de un programa de control de Enfermedad de Chagas Congénita en Bolivia / Cost effectiveness study of a control program of congenital Chagas disease in Bolivia

Cost effectiveness analysis of Chagas' vertical transmission control program in Bolivia: Today, Bolivia is the most concerned country in America by Chagas disease: Trypanosoma cruzi infection affects 20% of whole population, around 1800000 inhabitants, and mother-to-child transmission is around 5%, from 1.6 to 9.8%. Direct and indirect costs derived from disease complications and death, from birth to adulthood, add up around US$ 21 millions per year for 2,718 infected new-borns. This cost falls on individual, family and society, when the nation is struggling in a depressed economy. On the other side, an effective control program could detect and treat all cases with an investment of US$ 123 per infected new-born, or US$ 1.2 per new-born in Bolivia. Indirect benefits, apart of suffering relieve and improving of life quality, are related with Chagas vector control program, increasing the demand thanks to increasing risk awareness and also induced demand testing all pregnant women in endemic areas. So the conclusion is that such investment is profitable.

Los insecticidas actuales y las perspectivas de los nuevos para el futuro / Prospective and opportunistic analysis on insecticides for the future

La importancia de los pesticidas sintéticos orgánicos continuará creciendo acompañando al aumento de la población mundial y en tanto la proporción de tierra cultivable se mantenga relativamente constante. Los pesticidas permiten salvar el 10 por ciento de los cultivos pero todavía un 37 por ciento se pierden anualmente debido a la acción de las plagas. Se pueden tomar a los insecticidas como modelo para ilustrar la necesidad y posibilidades futuras de agroquímicos más eficaces y seguros para el hombre y su medio. Los insecticidas más importantes en ventas constituyen el 88 por ciento del total y actúan a nivel de sólo cuatro blancos moleculares (targets) nerviosos: Acetilcolinesterasa (AChE) el 62 por ciento; Canales de Sodio-dependientes de voltaje el 18 por ciento; Canales de Cloruro-dependientes de GABA (ácido gama aminobutírico) el 6 por ciento y Receptor Nicotínico para la acetilcolina el 2 por ciento. La utilidad de los tres "targets" primeros, será gradualmente comprometida debido a problemas de resistencia de insectos, en tanto que el receptor nicotínico para acetilcolina se espera que crezca significativamente. Los compuestos que actúan sobre targets No-Nerviosos se convertirán progresivamente en mucho más importantes. Dentro de éstos se incluyen a los desacoplantes de la fosforilación oxidativa, a los inhibidores de la NADH/Ubiquinona óxido-reductasa y a los inhibidores de la ATP-asa, a los reguladores del crecimiento (juvenoides, ecdisona) y a los pesticidas microbianos que actúan en varios nuevos targets. Con un panorama de 300 insecticidas comerciales disponibles en la actualidad y la prospectiva de introducción de no más de 2 ó 3 nuevos compuestos por año en promedio, sería esencial que se hiciera un uso lo más efectivo posible de los insecticidas corrientes. Los compuestos químicos más nuevos son en general más complejos y más costosos comparados con los anteriores, pero se los usa en general a dosis mucho menores resultando una relación costo/efectividad que resulta favorable a la economía minimizando además el impacto ambiental. Los nuevos compuestos son en general activos en contra de las cepas resistentes, integrales además a los programas de M.I.P. (manejo integrado de plagas) y suelen poseer una mínima toxicidad en los mamíferos

Utilizaçäo de óleos no controle de insetos em gräos armazenados / Utilization of oils for the control of insects stored grains

Na presente revisäo realizou-se um levantamento de informaçöes sobre a utilizaçäo de diferentes tipos óleos, tais como os óleos de amendoim, soja, coco, milho, algodäo, dendê, mostarda, gergelim, babaçu, mamona, entre outros, em mistura aos gräos armazenados para controle de insetos-praga, principalmente de bruquídeos em leguminosas e curculionídeos em cereais. Säo fornecidos dados sobre a eficiência dos óleos e das doses aplicadas, bem como um relato dos prováveis mecanismos de controle envolvidos. Diversos fatores parecem influir na eficiência dos óleos no controle dos insetos, tais como tipo de gräo tratado, tipo de óleo quanto à origem e processamento utilizado (bruto ou refinado), dose utilizada, temperatura e umidade ambientes, espécie de inseto a ser controlado e período de proteçäo requerido

A cost-benefit analisys of chagas disease control

Chagas disease transmission can be effetively interrupted by insecticidal control of its triatomine bug vectors. We present here a simple model comparing the costs and benefits of such a programme, designed to eliminate domestic populations of Triatoma infestans throughout its known area of distribution over the seven southernmost countries of Latin America. The model has been simplified to require only four financial estimates relating to the unit cost of housing spraying and benefits due to avoidance of premature death in the acute phase of the disease, avoidance of supportive treatment and care in the chronic phase of the disease, and avoidance of corrective digestive and cardiac surgery. Exceptfor these direct medical costs, al other potential benefits have been ignored. Nevertheless, the model shows that the direct financial benefits of such a programme would far outweigh the costs, and the project would support a remarkably high internal rate of return under the least optimistic estimates

Verificaçäo da eficácia de diferentes inseticidas no controle ambiental de Tunga penetrans (L., 1758) / Efficacy of various insecticides in the environmental control of Tunga penetrans (L., 1758)

Referências sobre o controle de Tunga penetrans a nível ambiental têm sido feitas, sem contudo se estabelecer critérios para avaliar a eficácia dos produtos. Neste trabalho usamos as variaçöes das prevalências obtidas e após o controle químico, como instrumento de avaliaçäo. Foram testados os piretróides cipermetrina na formulaçäo de concentrado emulsionável, CE, (Cymperator 25 CE) a 0,2%E 0,5%; deltametrina na formulaçäo de concentrado emulsionável CE, (K-Othrine 25 CE) a 0,6%e deltametrina na formulaçäo de concentrado de suspensäo ou flowable concentrate, SC, (K-Othrine 50 SC) a 0,3%. O resultado deste trabalho näo se baseia apenas na performance dos produtos testados, verificada através da variaçäo de prevalência, mas também em outros aspectos relevantes em saúde pública como a relaçäo custo/benefício; subisídio fundamentais em campanhas de saúde pública

Description of a mono-screen trap for Glossina fuscipes fuscipes Newstead in Uganda

A low-cost mono-screen trap for Glossina fuscipes fuscipes suitable for use by a rural community in Uganda is described. The trap has a single blue/black screen and a cone made from mosquito netting. The supporting framework is made from indigenous plant materials. The differences in trap catches between the mono-screen; biconical; pyramidal and vavoua traps were highly significant (P less than 0.001). Taking the standard biconical trap as control; the mono-screen trap was 1.25 times as efficient and the pyramidal trap was 0.04 times as efficient. The cost of one mono-screen trap is estimated as 1800 Uganda shillings (= U.S. $4.7); about half the cost of a pyramidal trap and one-quarter the cost of a biconical trap. The prospects for the use of the mono-screen trap by the community are discussed