Southern Cone Initiative Research Articles

Evolution of Chagas’ disease in Brazil. Epidemiological perspective and challenges for the future: a critical review

This article aimed to provide a critical review of the evolution of Chagas' disease (ChD) in Brazil, its magnitude, historical development and management, and challenges for the future. A literature search was performed using PubMed, SciELO and Google Scholar and throughout collected articles' references. Narrative analysis was structured around five main themes identified: vector transmission, control programme, transfusion, oral and congenital transmission. In Brazil, the Chagas' Disease Control Programme was fully implemented in the 1980s, when it reached practically all the endemic areas, and in 1991, the Southern Cone Initiative was created, aiming to control the disease transmission through eliminating the Triatoma infestans and controlling blood banks. As a result, the prevalence of chagasic donors in blood banks reduced from 4.4% in the 1980s to 0.2% in 2005. In 2006, Pan American Health Organization (PAHO) certified the interruption of transmission of ChD through this vector in Brazil. However, there are still challenges, such as the domiciliation of new vector species, the need for medical care of the infected individuals, the prevention of alternative mechanisms of transmission, the loss of political concern regarding the disease and the weakening of the control programme. Despite the progress towards control, there are still many challenges ahead to maintain and expand such control and minimise the risk of re-emergence.

Impact of vectorborne parasitic neglected tropical diseases on child health

Chagas disease, leishmaniasis, onchocerciasis and lymphatic filariasis are all vectorborne neglected tropical diseases (NTDs) that are responsible for significant disease burden in impoverished children and adults worldwide. As vectorborne parasitic...

A Scientometric Evaluation of the Chagas Disease Implementation Research Programme of the PAHO and TDR

The Special Programme for Research and Training in Tropical Diseases (TDR) is an independent global programme of scientific collaboration cosponsored by the United Nations Children's Fund, the United Nations Development Program, the World Bank, and the World Health Organization. TDR's strategy is based on stewardship for research on infectious diseases of poverty, empowerment of endemic countries, research on neglected priority needs, and the promotion of scientific collaboration influencing global efforts to combat major tropical diseases. In 2001, in view of the achievements obtained in the reduction of transmission of Chagas disease through the Southern Cone Initiative and the improvement in Chagas disease control activities in some countries of the Andean and the Central American Initiatives, TDR transferred the Chagas Disease Implementation Research Programme (CIRP) to the Communicable Diseases Unit of the Pan American Health Organization (CD/PAHO).This paper presents a scientometric evaluation of the 73 projects from 18 Latin American and European countries that were granted by CIRP/PAHO/TDR between 1997 and 2007. We analyzed all final reports of the funded projects and scientific publications, technical reports, and human resource training activities derived from them. Results about the number of projects funded, countries and institutions involved, gender analysis, number of published papers in indexed scientific journals, main topics funded, patents inscribed, and triatomine species studied are presented and discussed.The results indicate that CIRP/PAHO/TDR initiative has contributed significantly, over the 1997–2007 period, to Chagas disease knowledge as well as to the individual and institutional-building capacity.

Control Using Genetically Modified Insects Poses Problems for Regulators

Control Using Genetically Modified Insects Poses Problems for Regulators

In vitro and in vivo experimental models for drug screening and development for Chagas disease

Chagas disease, a neglected illness, affects nearly 12-14 million people in endemic areas of Latin America. Although the occurrence of acute cases sharply has declined due to Southern Cone Initiative efforts to control vector transmission, there still remain serious challenges, including the maintenance of sustainable public policies for Chagas disease control and the urgent need for better drugs to treat chagasic patients. Since the introduction of benznidazole and nifurtimox approximately 40 years ago, many natural and synthetic compounds have been assayed against Trypanosoma cruzi, yet only a few compounds have advanced to clinical trials. This reflects, at least in part, the lack of consensus regarding appropriate in vitro and in vivo screening protocols as well as the lack of biomarkers for treating parasitaemia. The development of more effective drugs requires (i) the identification and validation of parasite targets, (ii) compounds to be screened against the targets or the whole parasite and (iii) a panel of minimum standardised procedures to advance leading compounds to clinical trials. This third aim was the topic of the workshop entitled Experimental Models in Drug Screening and Development for Chagas Disease, held in Rio de Janeiro, Brazil, on the 25th and 26th of November 2008 by the Fiocruz Program for Research and Technological Development on Chagas Disease and Drugs for Neglected Diseases Initiative. During the meeting, the minimum steps, requirements and decision gates for the determination of the efficacy of novel drugs for T. cruzi control were evaluated by interdisciplinary experts and an in vitro and in vivo flowchart was designed to serve as a general and standardised protocol for screening potential drugs for the treatment of Chagas disease.

New, improved treatments for Chagas disease: from the R&D pipeline to the patients.

Endemic throughout Latin America with a prevalence rate of approximately 1.4%, Chagas disease (CD) is estimated to kill 14,000 people every year, which is more people in the region each year than any other parasite-born disease, including malaria [1],[2]. Brazilian physician Carlos Chagas first described CD exactly a century ago [3], and its socioeconomic impact makes it the most important parasitic disease in the Americas [4]. Estimated to infect somewhere between 8 to 14 million people, CD both afflicts the poor and, like other neglected tropical diseases, “promotes poverty” [2],[5]. Through its impact on worker productivity, and by causing premature disability and death, CD annually costs an estimated 667,000 disability-adjusted life years lost [1],[6]. In the case of Brazil alone, losses of over US$1.3 billion in wages and industrial productivity were due to the disabilities of workers with CD [7]. CD is an important public health issue, both in Latin America and increasingly around the world: the infection rate in endemic areas is estimated to be 1.4% [8], with geographic variation from 0.1% to 45.2% [9]. Vectorial transmission has been significantly reduced due to control efforts like the Southern Cone Initiative [10],[11] and others [11],[12]. However, there are areas producing new cases such as regions untouched by vector control efforts [13], special areas with non-domiciliated triatomine [14], and the Amazon region with recent cases reported via oral transmission and by wild triatomine [15]. And still to this day, millions of patients remain without adequate treatment for this silently debilitating and potentially fatal disease. Although no official global figures exist, it is estimated that no more than 1% of those infected are believed to receive any treatment at all. An increasing number of CD patients are also seen in non-endemic, developed countries because of globalization and the movement of unknowingly infected people from Latin America to other parts of the world [16],[17],[18]. The appearance of Trypanosoma cruzi in blood banks in the United States has led the Food and Drug Administration (FDA) to recently issue a draft guidance on CD screening [19].

The elimination of Chagas' disease from Brazil.

On 9 June 2006 the Pan American Health Organization (PAHO) presented the Minister of Health of Brazil with the International Elimination of Transmission of Chagas' Disease Certificate. This act was the culmination of an intensive process that began in 1991 with the Southern Cone Initiative, a joint agreement between the governments of Argentina, Bolivia, Brazil, Chile, Paraguay, Uruguay and Peru, to control Chagas' disease by the elimination of the main vector, Triatoma infestans. This initiative has been highly successful and the prevalence area of the vector diminished rapidly in the last years. As a consequence, the current seroprevalence in children aged between 0 and 5 years is of the order of 10(-5), a clear indication that transmission, if it is occurring, is only accidental. In this review I calculate the basic reproduction number, R0, for Chagas' disease and demonstrate that its relatively low value (1.25) explains why vectorial transmission was interrupted relatively easily. In addition, I used a mathematical model to forecast how long the remaining cases of the disease, as well as the additional vertically transmitted cases will last.

Southern Cone Initiative for the elimination of domestic populations of Triatoma infestans and the interruption of transfusion Chagas disease: historical aspects, present situation, and perspectives

Created in 1991 by the governments of Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay, the Southern Cone Initiative (SCI) has been extremely important for Chagas disease control in this region. Its basic objective was to reach the interruption of this disease, chiefly by means of the elimination of the principal vector Triatoma infestans and by the selection of safe donors in the regional blood banks. After a summarized historic of SCI, the text shows the advance of technical and operative activities, emphasizing some factors for the initiative success, as well as some difficulties and constraints. The future of SCI will depend of the continuity of the actions and of political priority. Scientific community has been highly responsible for this initiative and its maintenance. At the side of this, national and international efforts must be involved and reinforced to assure the accomplishment of the final targets of SCI. Very specially, the Pan American Health Organization has cooperated with the Initiative in all its moments and activities,being the most important catalytic and technical factor for SCI success.

Working group: social, epidemiological, and control determinants of Chagas disease in American Southern Cone

Discussion was opened with the aim to contributewith the ALCUEH net work in preparation of a basis fortraining, divulgation, and definition of national policiesconcerning neglected diseases, in the context of South-ern Cone Initiative for Chagas Disease (INCOSUR).The first presentation (Joao Carlos Pinto Dias) sum-marized the most important historical and political an-tecedents of the initiative, as well as its most recent ad-vances and principal challenges in the new millennium.JR Coura - Starts the discussion asking the partici-pants to focus their interventions in the three main pur-poses of the meeting, such as: (a) the neglected and oremergent aspects of the disease, requiring additionalinformation to improve the pertinent political action; (b)the main projects for control qualifying and technologi-cal transfer; and (c) the regional details for each par-ticular project. As an specific question, ask the partici-pants their opinion about what to do with the othertriatominae species in the Region, following the elimi-nation of Triatoma infestans.A Rojas de Arias - Giving her thanks for the invita-tion and nomination, she remembers that INCOSUR –besides its general and epidemiological purposes, hasadditionally the task for being an example and a modelfor similar initiatives in the whole region.AC Silveira - Remembers that the secondary and na-tive species cannot be eliminated, so obliging us to livetogether with them, looking for a situation of low den-sity and no colonization. The strategy will be a continu-ous and strict surveillance, in all endemic areas, focusedin the determination of the main risk factors for thevectoral Chagas disease transmission, such as the infes-tation degree, the colonization capacity, and the antro-pophilic characteristic of each species. Finally, pointsout that, in Brazil, the most important species in the ar-eas where T. infestans has been eliminated areT. brasiliensis, T. pseudomaculata, T. sordida, and Pans-trongylus megistus.R Zeledon - Agreeing with JC Pinto Dias exposition,reinforces its political aspects and launches two generaland one technical questions: (a) since the vector elimi-nation represents a political question and consideringthat in general political actions are discontinuous andnot stable, is it really the elimination an attainable goal?(b) What can be made to reinforce the political decisionof national governments, so avoiding the loosing of theprimary objectives? (c) Is it possible that residual Tri-atominae populations recover the initial scenery of hous-ing infestation?AC Silveira (answering Dr Zeledon) - It is very dif-ficult the recovery of controlled Triatominae popula-tions, specially in the case of T. infestans and after theconclusion of chemical attack phase. This recovery isgenerally too slow and the regular surveillance actionsgenerally avoid indoors reinfestation. In Southern Conemost of T. infestans residual foci are peridomestic andthe few and scarce sylvatic foci of this species seem torepresent no significant danger for housing colonization.To sustain an effective surveillance it is required a goodand fast feed back capacity in a local and decentralizedhealth system, monitored and supported by national andregional health unities. A very frequent and preoccupantgap in such an approach consists in the insufficient and fewtrained local teams, with the lack of regional supervision.AR Prata - Three main questions arise from this sub-ject: (a) the need to insist in the elimination of otherspecies strictly domiciliated, as the case of P. megistusin great part of Bahia, Brazil; (b) to maintain the regularepidemiological surveillance against the peridomesticspecies, looking for their withdrawal of indoors spaceas great as possible; (c) the need to keep in mind that thepresent success of control programs will certainly to befollowed by several difficulties to maintain the priorityfor the control action.Prof. Prata still considered that the priorities in Cha-gas disease tend to go down. Nevertheless, epidemio-logical surveillance will be required for a long time, be-ing necessary to maintain it, as it has been done for thecases of the plague and yellow fever. He remembers thatin the past several rationalities were invoked to impedethe starting of regular programs, including in Brazil. Forinstance, interminable academic discussions were car-ried on, concerning the options between housing im-provement and chemical fight for vector control. By an-other angle, chiefly in situations of decentralization,other priorities and problems of the local communitiesuse to result in governmental deviations from the Chagasdisease program objectives. It is the case, for instance,of several epidemics of dengue fever in Brazil, requir-ing human resources and even insecticides which fre-

Migração interna e a distribuição da mortalidade por doença de Chagas, Brasil, 1981/1998

In Brazil, mortality from Chagas disease occurs even in regions classified as free of vector transmission. Because death rates refer to residents, and considering that a huge migratory movement has occurred inside the country, this study was intended to quantify the contribution of Brazilian internal migration to overall mortality from Chagas disease, from 1981 to 1998. If the PAHO Southern Cone Initiative actually achieved its objectives, one could expect declining death rates and increasing age at death from this cause. The results showed that out of 68,936 deaths in Brazilians with known birthplace, 32,369 (32%) occurred in people born in States other than those of their current residence (range: from 0.3% in Rio Grande do Sul to 100% in Roraima and Amapá). Most (67%) of the deaths in migrants occurred in individuals born in the States of Minas Gerais (51%) and Bahia (16%). Death rates in residents showed a consistent decline in the Southeast, South, and Central West of the country, but not in the Northeast and North, where median age at death was the lowest.

Wing shape divergence between Rhodnius prolixus from Cojedes (Venezuela) and Rhodnius robustus from Mérida (Venezuela)

The existence of Rhodnius robustus as a species distinct from Rhodnius prolixus has long been the main epidemiological question about Chagas disease transmission in Venezuela and surrounding countries. These two taxa are morphologically and genetically very similar, but only R. prolixus is assumed to colonize houses and transmit Chagas disease to humans. R. robustus is assumed to be an exclusively sylvatic species, restricted to palm trees. If robustus and prolixus are actually the same species, the theoretical possibility exists of sylvatic specimens invading houses, even after insecticide application, and a control strategy similar to that of the successful Southern Cone Initiative against Triatoma infestans would be difficult to consider. Since no valid alternative control strategy exists, the answer to this biological question could be decisive about the future of vector control in this region. Although we believe genetic techniques are best suited to define species boundaries, we present here an example of the relevance of modern morphometrics in dealing with such an issue. Using both traditional and geometric morphometrics, we compared the wing size and shape in both sexes of these two taxa reared in the same laboratory for one generation. R. robustus specimens were collected from palm trees in the state of Mérida (Venezuela), and R. prolixus were collected from houses in the state of Cojedes (Venezuela). Our study provided no argument to question their specific status. Even after one generation of living in the same laboratory conditions, the two lines showed clear size differences, divergent allometric trends, and significant allometry-free differences in shape. These results suggest that R. robustus (Mérida, Venezuela) and R. prolixus (Cojedes, Venezuela) are distinct evolutionary units. Due to the epidemiological importance of this question, further studies in other geographic areas of Venezuela are required to accurately define the relationships of R. robustus and R. prolixus.

The impact of Chagas disease control in Latin America: a review.

Discovered in 1909, Chagas disease was progressively shown to be widespread throughout Latin America, affecting millions of rural people with a high impact on morbidity and mortality. With no vaccine or specific treatment available for large-scale public health interventions, the main control strategy relies on prevention of transmission, principally by eliminating the domestic insect vectors and control of transmission by blood transfusion. Vector control activities began in the 1940s, initially by means of housing improvement and then through insecticide spraying following successful field trials in Brazil (Bambui Research Centre), with similar results soon reproduced in São Paulo, Argentina, Venezuela and Chile. But national control programmes only began to be implemented after the 1970s, when technical questions were overcome and the scientific demonstration of the high social impact of Chagas disease was used to encourage political determination in favour of national campaigns (mainly in Brazil). Similarly, large-scale screening of infected blood donors in Latin America only began in the 1980s following the emergence of AIDS. By the end of the last century it became clear that continuous control in contiguous endemic areas could lead to the elimination of the most highly domestic vector populations - especially Triatoma infestans and Rhodnius prolixus - as well as substantial reductions of other widespread species such as T. brasiliensis, T. sordida, and T. dimidiata, leading in turn to interruption of disease transmission to rural people. The social impact of Chagas disease control can now be readily demonstrated by the disappearance of acute cases and of new infections in younger age groups, as well as progressive reductions of mortality and morbidity rates in controlled areas. In economic terms, the cost-benefit relationship between intervention (insecticide spraying, serology in blood banks) and the reduction of Chagas disease (in terms of medical and social care and improved productivity) is highly positive. Effective control of Chagas disease is now seen as an attainable goal that depends primarily on maintaining political will, so that the major constraints involve problems associated with the decentralisation of public health services and the progressive political disinterest in Chagas disease. Counterbalancing this are the political and technical cooperation strategies such as the "Southern Cone Initiative" launched in 1991. This international approach, coordinated by PAHO, has been highly successful, already reaching elimination of Chagas disease transmission in Uruguay, Chile, and large parts of Brazil and Argentina. The Southern Cone Initiative also helped to stimulate control campaigns in other countries of the region (Paraguay, Bolivia, Peru) which have also reached tangible regional successes. This model of international activity has been shown to be feasible and effective, with similar initiatives developed since 1997 in the Andean Region and in Central America. At present, Mexico and the Amazon Region remain as the next major challenges. With consolidation of operational programmes in all endemic countries, the future focus will be on epidemiological surveillance and care of those people already infected. In political terms, the control of Chagas disease in Latin America can be considered, so far, as a victory for international scientific cooperation, but will require continuing political commitment for sustained success.

Kinetoplastid Internet Symposium: A KISs for 2002.

Wanderley de Souza (Universidade Federal do Rio de Janeiro, Brazil) offered to head up the scientific agenda with a comprehensive description of how breakthroughs in the study of trypanosome cell biology could be translated into new drug targets and into affirmative action in combating disease. Kwang-Poo Chang (Chicago Medical School, IL, USA) and Brad McGwire (University of Illinois, IL, USA) focused on pathoantigenic determinants and their role in determining the virulence and pathogenesis of leishmaniasis, particularly on the complex interactions between multiple determinants, which can lead to various outcomes. The online discussion forum was then used to explore the importance of these antigenic determinants in the fabrication of immunoprophylactics, especially with regard to live attenuated Leishmania vaccines.Serap Aksoy (Yale University School of Medicine, CT, USA), Zhengrong Hao (Yale University School of Medicine) and Patricia Strickler (Yale University School of Medicine) authored an intriguing discussion on the importance of molecular studies directed at dissecting tsetse–trypanosome interactions. The response role of insect defensins and the possible use of paratransgenic tsetse with transformed Wolbachia (rendering tsetse refractory to trypanosome infection) were discussed in the article and online.Joao Carlos Dias (Oswaldo Cruz Foundation, Belo Horizonte, Brazil) and Christopher Schofield (London School of Hygiene and Tropical Medicine, UK) presented a fascinating report highlighting the current status of Chagas disease control throughout Latin America. The report emphasized the need to capitalize on recent gains made by regional programs, such as the Southern Cone Initiative, to prevent the disease re-emerging in areas where transmission has effectively been eliminated. Moreover, such programs should be extended into regions where the disease is still endemic. In particular, the report highlighted research areas that are most likely to produce significant steps forward in combating Chagas disease including triatomine sampling, migratory behavior and epidemiological analysis, improved serological tests, new drug designs and analysis of regional program structures.Finally, a strong poster session covering advances from the fields of diagnostics and chemotherapy was presented online. One significant presentation from Wendy Gibson et al. (University of Bristol, UK) described markers that identified Trypanosoma brucei rhodesiense from other members of the Trypanosoma brucei complex. Other presentations covered the phylogenetic identity of Leishmania mexicana (Amalia Monroy-Ostria and Omar Hernandez-Montes, Col. Casco de Santo Tomas, Mexico) and the T. brucei genome initiative using single nucleotide polymorphisms (SNPs) suitable for population analysis in African trypanosomes (Emmanuelle Bart-Delabesse et al., University of Cambridge, UK). The use of internal transcribed spacer ribosomal DNA (ITS-rDNA) for diagnosing Trypanosoma lewisi in laboratory animals was also described by Marc Desquesnes and colleagues (Centre International de Recherche-Developpement sur l'Elevage en zone Subhumide, Burkina Faso). Posters on veterinary chemotherapeutics by Alain Bourdichon et al. (Atarost, Hamburg, Germany) discussed the efficacy of diminazene against Trypanosoma evansi in combination with antipyrine or Trypan (procaine) and using liposomes as a delivery vehicle.Until the launch of Kinetoplastid Biology and Disease, articles from the conference will remain online at http://www.trypanosome.com We invite volunteers interested in co-ordinating further Internet meetings or developing integrated Internet resources for kinetoplastid diseases to contact us.

Epidemiology of Chagas disease in Mexico: an update.

With the continuing success of the Southern Cone Initiative against Chagas disease and steady progress of the Andean pact and Central American Initiatives, Mexico is among the last countries of Latin America to instigate a large-scale programme against Trypanosoma cruzi transmission. However, a national policy concerning Chagas disease control in Mexico has recently been developed. The Ministry of Health has approved a law about screening for anti-T. cruzi antibodies in the whole territory. Also, epidemiological surveillance and vector control programmes have started to inform regulation.

Parasitological cure of Chagas disease: is it possible? Is it relevant?

Nearly 90 million people (about a quarter ofthe Latin American population) live in zones whereChagas disease is endemic while 18-20 million arealready infected with is causative agent, Trypano-soma (Schizotrypanum) cruzi. It is estimated thatthere are currently >550,000 new cases and 50,000deaths associated to this condition every year(Docampo & Schmunis 1997). This disease leadsto an annual loss of 2.7 millions of disability ad-justed years, being the largest parasitic diseaseburden in the continent and only third on a globalscale after malaria and schistosomiasis (WorldBank 1993). Chemotherapy of this disease is stillvery unsatisfactory, being based in nitrofurans(nifurtimox, Bayer; recently discontinued) andnitroimidazoles (benznidazole, Roche) developedempirically three decades ago. These compoundshave activity in the acute and short-term (up to afew years) chronic phase (Andrade et al.1996), butis efficacy varies according to the geographicalarea, probably due to differences in drug suscepti-bility of different T. cruzi strains (Filardi & Brener1987); however, they have little or no activity inprevalent, long term chronic form of the disease,which is widely considered an incurable disease(Rassi & Luquetti 1992, de Castro 1993, Quintaset al.1996, Andrade et al.1996, Croft et al.1997).Furthermore, both drugs have frequent side effects(generally less severe in pediatric patients) includ-ing anorexia, vomiting, peripheral neuropathy andallergic dermopathy (Rassi & Luquetti 1992, deCastro 1993, Quintas et al.1996, Croft et al.1997).Although great advances have been made in re-cent years in the control of the vectorial and trans-fusional transmission of the disease, particularlythrough the Southern Cone Initiative involvingBrazil, Argentina, Paraguay and Uruguay, progressis uneven in other parts of the continent and theproblem of the persons already infected remainsunsolved.In this brief review I would like to discuss re-cent work, involving the joint effort of biochem-ists, chemists, parasitologists, molecular and cellbiologists and immunologists, that have raised thepossibility of radical parasitological cure in chroni-cally infected experimental animals and humansthorough rational chemotherapeutic approaches. Iwould also like to discuss the role of parasites inthe pathogenesis of chronic Chagas disease andthus the relevance of parasitological cure in theclinical outcome of this disease. A more extendedversion of this discussion has been presented else-where (Urbina 1999).

The Southern Cone Initiative against Chagas Disease

Chagas disease (also known as American trypanosomiasis) is now ranked as the most serious parasitic disease of the Americas, with an economic impact far outranking the combined effects of other parasitic diseases such as malaria, schistosomiasis and leishmaniasis. Although the chronic infection remains virtually incurable, transmission can be halted by eliminating the domestic insect vectors and screening blood donors to avoid transfusional transmission. In line with this strategy, governments of the six Southern Cone countries (Argentina, Bolivia, Brazil, Chile, Paraguay and Uruguay) launched in 1991 an ambitious initiative to control Chagas disease through elimination of the main vector, Triatoma infestans, and large-scale screening of blood donors. Now at its mid-point, the programme has achieved remarkable success, with transmission halted over vast areas of the previously endemic regions. Well over 2 million rural houses have been sprayed to eliminate T. infestans, and the programme has already shown significant economic rates of return in addition to the medical and social benefits.

The control of the transmission by transfusion of Chagas' disease in the Southern Cone Initiative

The Southern Cone Initiative against Chagas' disease, was launched in 1991. The aim was to interrupt the transmission of Chagas disease by elimination of domestic populations of the major vector, Triatoma infestans, and by improved screening of blood donors. As a result of these activities, a marked reduction in the risk of transfusional transmission can now be seen throughout the programme area. In addition to specific legislation concerning the quality of transfused blood, a series of national and regional reference laboratories have been set up with the help of PAHO in order to improve the quality of pre-transfusional serodiagnosis. Results indicate a progressive reduction in the overall infection prevalence of blood donors, and show that the age-prevalence curve has shifted towards older age-groups. In this paper we analyse the changes in infection prevalence in the Southern Cone countries, drawing attention to the situation in Bolivia which has the highest indices of infection and lowest levels of coverage by the control programme. In this situation chemoprophylaxis of blood prior to transfusion may be recommended in accordance with PAHO criteria. In the medium term however, interruption of human Chagas disease transmission may be expected over most of the Southern Cone region, as long as the control activities are continued and consolidated through effective epidemiological surveillance.

South America: Southern cone initiative against Chagas disease

South America: Southern cone initiative against Chagas disease

Chagas disease vector control in Central America

As the Southern Cone Initiative proceeds steadily towards eradication of Triatoma infestans, there is increasing interest in applying similar approaches to control Chagas disease vectors in Mexico, Central America and countries of the Andean Pact. Here, Chris Schofield and Jean-Pierre Dujardin discuss the technical feasibility of such an approach.