Epidemiology of Chagas disease in non endemic countries: the role of international migration

Human infection with the protozoa Trypanosoma cruzi extends through North, Central, and South America, affecting 21 countries. Most human infections in the Western Hemisphere occur through contact with infected bloodsucking insects of the triatomine species. As T. cruzi can be detected in the blood of untreated infected individuals, decades after infection took place; the infection can be also transmitted through blood transfusion and organ transplant, which is considered the second most common mode of transmission for T. cruzi. The third mode of transmission is congenital infection. Economic hardship, political problems, or both, have spurred migration from Chagas endemic countries to developed countries. The main destination of this immigration is Australia, Canada, Spain, and the United States. In fact, human infection through blood or organ transplantation, as well as confirmed or potential cases of congenital infections has been described in Spain and in the United States. Estimates reported here indicates that in Australia in 2005-2006, 1067 of the 65,255 Latin American immigrants (16 per 1000) may be infected with T. cruzi, and in Canada, in 2001, 1218 of the 131,135 immigrants (9 per 1000) whose country of origin was identified may have been also infected. In Spain, a magnet for Latin American immigrants since the 2000, 5125 of 241,866 legal immigrants in 2003 (25 per 1000), could be infected. In the United States, 56,028 to 357,205 of the 7,20 million, legal immigrants (8 to 50 per 1000), depending on the scenario, from the period 1981-2005 may be infected with T. cruzi. On the other hand, 33,193 to 336,097 of the estimated 5,6 million undocumented immigrants in 2000 (6 to 59 per 1000) could be infected. Non endemic countries receiving immigrants from the endemic ones should develop policies to protect organ recipients from T. cruzi infection, prevent tainting the blood supply with T. cruzi, and implement secondary prevention...

La reforma del sector salud, descentralización, prevención y control de enfermedades transmitidas por vectores / Health system, decentralization, and the control of vector-borne disease

Con las nuevas macropolíticas mundiales, la salud en América Latina ha sufrido importante transición en direción a la decentralización, sin compatibilizar la salud pública con la lógica de las economías de mercado. Con esto, el control decentralizado de las enfermedades endémicas presenta dificultades políticas y operativas. Aunque la decentralización se justifica por los presupuestos teóricos, no hay tradición de este control en los niveles municipales, lo que dificulta la simple o burocrática transferencia de encargos para estos niveles. La falta de expertise, el turn-over político y la corrupción son dificultades adicionales, conllevando a una extinción de varias instituiciones y programas. La falta de efectividad en el enfrentamiento del dengue, de la malaria y de la enfermedad de Chagas son algunos ejemplos. Requierese una modernización con responsabilidad, con una transición compartida entre los niveles y garantizada por acciones continuadas. Sugierese mantener estructuras regionales para referência, consolidación epidemiológica, normatización, capacitación y supervisión, incluso con reserva técnica para acciones finalísticas supletivas.

Prevention of transfusional Trypanosoma cruzi infection in Latin America

Trypanosoma cruzi is a protozoan infection widely spread in Latin America, from Mexico in the north to Argentina and Chile in the south. The second most important way of acquiring the infection is by blood transfusion. Even if most countries of Latin America have law/decree/norms, that make mandatory the screening of blood donors for infectious diseases, including T. cruzi (El Salvador and Nicaragua do not have laws on the subject), there is usually no enforcement or it is very lax. Analysis of published serologic surveys of T. cruzi antibodies in blood donors done in 1993, indicating the number of donors and screening coverage for T. cruzi in ten countries of Central and South America indicated that the probability of receiving a potentially infected transfusion unit in each country varied from 1,096 per 10,000 transfusions in Bolivia, the highest, to 13.02 or 13.86 per 10,000 transfusions in Honduras and Venezuela respectively, where screening coverage was 100 per cent. On the other hand the probability of transmitting a T. cruzi infected unit was 219/10,000 in Bolivia, 24/10,000 in Colombia, 17/10,000 in El Salvador, and around 2-12/10,000 for the seven other countries. Infectivity risks defined as the likelihood of being infected when receiving an infected transfusion unit were assumed to be 20 per cent for T. cruzi. Based on this, estimates of the absolute number of infections induced by transfusion indicated that they were 832, 236, and 875 in Bolivia, Chile and Colombia respectively. In all the other countries varied from seven in Honduras to 85 in El Salvador. Since 1993, the situation has improved. At that time only Honduras and Venezuela screened 100 per cent of donors, while seven countries, Argentina, Colombia, El Salvador, Honduras, Paraguay, Uruguay and Venezuela, did the same in 1996. In Central America, without information from Guatemala, the screening of donors for T. cruzi prevented the transfusion of 1,481 infected units and the potential infection of 300 individuals in 1996. In the same year, in seven countries of South America, the screening prevented the transfusion of 36,017 infected units and 7, 201 potential cases of transfusional infection.

Tourism and emerging and re-emerging infectious diseases in the Americas: What physicians must remember for patient diagnosis and care

Emerging diseases are those which have shown an increased in humans over the last 20 years. Re-emerging diseases are those which have reappeared after a period of significant decrease in incidence. The etiological agents of these diseases in the Western Hemisphere are viroses (HIV, dengue, oroupuche, sabia, guanarito, or hanta), bacteria (Vibrio cholera, Borrellia burgdorferi, Legionella pneumofila, Escherichia coli O157:H7, or other bacteria with a new pattern of antibiotic resistence), or parasites (Cryptosporidia, Cyclosporidia or drug resistant Plasmodium falciparum). Due to the widespread geographical distribution of these infectious diseases in the Americas, and an increasing number of travellers (more than 87 milion persons within the region in 1997), there are many opportunities to contract an infection when travelling in developed or undeveloped countries. The infections may present with symptoms during the trip, or following the traveler's return to his or her place of origin. However, too often practicing physicians do not inquire about the travel history of their patients and, when they do, they often lack the information about diseases relevant to travelers. From the regional perspective, the emerging or reemerging agents that pose a higher risk to tourists or travelers are: 1) those that cause enteric infections; 2) sexually transmitted diseases; and 3) vector-borne diseases, including those present in ecotourism areas. Emerging and re-emerging diseases that physicians may encounter in their clinical practice while caring for travelers returning from different countries of the Western Hemisphere are briefly described (Lyme diseases, legionellosis, dengue, yellow fever, P. falciparum malaria, cyclosporidiosis and cryptosporidiosis). This report attempts to draw attention to the fact that new clinical and etiological entities are present in several geographical areas of the Americas; to place each of the these entities into an epidemiological context; and to end the misconception that only travel to poor coutries carries a risk of acquiring an infection. By knowing which infectious agents occur in each area and the incubation period of each disease, the treating physician can often patients sucessfully. Health care professionals must be aware of the organisms circulating in the region so that they have them in mind during their clinical practice.

Riesgo de la enfermedad de Chagas a traves de las transfusiones en las Americas / Risk of Chagas disease through transfusions in the Americas

La seguridad de la transfusión sanguínea tanto de la existencia en el país de leyes, decretos y/o reglamentos que normal la obtención, producción y uso de sangre y derivados y la decisión gubernamental de hacerlos cumplir, como de profesionales de salud capacitados para obtener sangre y producir hemoderivados imbuidos de los conceptos de garantía de calidad total en la obtención, producción y uso de los mismos. Con la excepción de El Salvador y Nicaragua, todos los países latinoamericanos poseían leyes, decretos y/o regulaciones que regían la producción y el uso de sangre en 1998. Las penurias económicas en América latina han estimulado la emigración a las zonas urbanas en las seis últimas décadas. Como consecuencia, más del 60 por ciento de la población vive actualmente en las ciudades, lo que aumenta la probabilidad de infección por T. cruzi en donantes de sangre. Mientras no se descarte la sangre de los donantes infectados, existirá la posibilidad de transmitir la infección por medio de la transfusión. Asimismo, la infección transfusional por T. cruzi es un problema potencial en los países desarrollados, ya que decenas de miles de latinoamericanos han emigrado a los Estados Unidos, Canadá, los países de Europa Occidental, Australia o Japón. Cuando no se lleva a cabo la serología para T. cruzi en los donantes, el riesgo de recibir una unidad infectada se incrementará cuanto mayor sea la prevalencia de la infección en la población de nonantes y el número de transfusiones recibidas por el receptor. En 1993, el riesgo mayor de recibir unidad infectada y de infectarse con T. cruzi estaba en Bolivia, seguido de Colombia, El Salvador y Paraguay. Como la cobertura de la serología para VIH fue casi universal, la probabilidad de recibir una unidad infectada o de infectarse, fue baja para todos los países. La probabilidad fue mayor para HVB, sobre todo en Bolivia, Nicaragua y Guatemala; y aún mayor para HVC, debido a la baja cobertura del tamizaje de donantes. En números absolutos, el país donde se trasnmitieron más casos potenciales de infección por T. cruzi fue Bolivia; mayor número de casos de HVC, en Colombia; y más casos de HVB, en Nicaragua. Sólo en dos países, Bolivia y Colombia, existiría el potencial de transmitir VIH por medio de la transfusión. Si bien la situación ha mejorado desde 1993, y al 100 por ciento de los donantes....