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São revistas evidências experimentais e observações de terreno que demonstram a transmissão do Trypanosoma cruzi ao homem e vários mamíferos pela via oral, que ocorre especialmente no ciclo enzoótico do parasita. Vários tipos de alimentos e veículos de carreamento do flagelado têm sido implicados nesta modalidade de transmissão, geralmente sendo os casos humanos relacionados com triatomíneos infectados nas imediações do evento. Sumariam-se as vias de penetração (mucosas da boca, esôfago, estômago e intestino) e se descrevem os principais eventos anatomopatológicos, tais como fenômenos hemorrágicos, mesenterite e hepatite intersticial. Em particular são analisados aspectos da biologia e da bioquímica do parasita, com vistas à epidemiologia da transmissão oral e às possibilidades de sua prevenção na doença de Chagas.Experimental evidence and field observations concerning the oral transmission of Trypanosoma cruzi to human beings and mammalian species are reviewed, confirming its unquestionable occurrence, mainly in the enzootic cycle of the parasite. Several types of foods and carriers of the flagellate have been involved in this transmission route, where the human cases are generally related to infected triatomines and/or natural reservoirs in the proximities of the event. The penetration points of the parasite (mouth, esophagus, stomach and intestinal mucosae) are reviewed, as well as the general anatomic and pathological processes, such as hemorrhagic phenomena, mesenteritis and interstitial hepatitis. In particular, different aspects of the biology and biochemistry of the parasite are analyzed, especially in terms of its epidemiology and the possibilities of the prevention of the oral transmission of Chagas' disease.

There are currently two major factors that have modified the epidemiology of Chagas disease in the last decades: climate change and migration flows. In this new scenario, there are new challenges to control and prevent Trypanosoma cruzi infection in endemic countries, such as the control of a wider distribution of triatomine vectors or the reinforcement of vertical transmission programs. In non-endemic areas, few countries are aware of the emergence of this new disease and have established changes in their health systems. To address this new public health challenge, the priorities should be control programs to avoid new cases of T. cruzi infection acquired through vertical transmission, blood transfusion or organ transplant. In both, endemic and non-endemic areas, the international community and all the actors involved in Chagas disease must join efforts mainly in two directions: better management of the infection in affected individuals and more research to cover the knowledge gap mainly in physiopathology, diagnosis and treatment. [ABSTRACT FROM AUTHOR]

American trypanosomiasis is one of the few native parasites of this continent. As a zoonosis, Trypanosoma cruzi infects about 180 species out of 25 families of mammals. Its regular transmission is through triatomines, which can easily transmit parasites either by the skin route (contamination of mammals skin with their feces) or by oral route (ingestion of food contaminated with complete triatomines or their feces) and additionally through haematogenous via (congenital and transfusional) and by tissues (transplants). The oral route, which seems to be the ancestral form of transmission to wild and domestic mammals, has recently become more important after the success achieved in the control of domicile vectors using residual pesticides. From its initial diagnosis in 1967, tens of oral outbreaks have been diagnosed mostly in the Brazilian Amazon and subsequently in other four countries in South America. Environmental imbalance caused by man through the invasion and deforestation of woodlands, results in reduction of biodiversity of mammals as food source for triatomines, affecting the “dilution effect” of T. cruzi in the nature increasing the risk of human infection. On the other hand, triatomines invade houses looking for new blood sources. One of the consequences of domiciliated triatomines is the food contamination spread, especially in home-made juices, which has been the source of infection of most oral outbreaks. Other biotic and abiotic factors help to explain the recent increase of oral transmission outbreaks of Chagas disease, distributed in nine eco-regions of America. [ABSTRACT FROM AUTHOR]

The outbreak of acute Chagas disease due to oral transmission of the parasite is a well-known phenomenon mainly occurring in the Amazon. Such an event is described here for the first time in French Guiana. Eight patients of the same family, presenting epidemiological and clinical histories compatible with recent Trypanosoma cruzi infection of Chagas disease due to the ingestion of palm Oenocarpus bacaba juice were, rather late after the putative date of infection, underwent four parasitological and two serological specific tests for confirmation of the diagnosis. Real-time PCR results were positive for all the patients; strains were isolated by hemoculture from four patients, PCR identification of TcI DTU was made for six patients, while parasites were not detected in any of the patients by direct microscopic examination. The results of two serologic tests were positive. All patients were treated with benznidazole, and two patients were additionally given nifurtimox. A 6-year follow-up was possible for six patients. Real-time PCR was negative for these patients after 1 year, while the antibody rates decreased slowly and serology results were negative only after several years (1–5 years). Our findings confirm the occurrence of an outbreak of Chagas infection in members of the same family, with the oral mode of infection being the most likely hypothesis to explain this group of cases. Our results show the successful treatment of patients infected by TcI and the usefulness of real-time PCR for the emergency diagnosis of recent Chagas disease cases and in posttreatment follow-up. [ABSTRACT FROM AUTHOR]

Abstract: The notion of evolutionary trade-off (one attribute increasing at the expense of another) is central to the evolution of traits, well-studied especially in life-history theory, where a framework first developed by Levins illustrates how internal (genetics) and external (fitness landscapes) forces interact to shape an organism׳s ongoing adaptation. This manuscript extends this framework to the context of vector-borne pathogens, with the example of Trypanosoma cruzi (the etiological agent of Chagas׳ disease) adapting via trade-off among three different infection routes to hosts—stercorarian, vertical, and oral—in response to an epidemiological landscape that involves both hosts and vectors (where, in particular, parasite evolution depends not on parasite density but on relative host and vector densities). Using a fitness measure derived from an invasion reproductive number, this study analyzes several different trade-off scenarios in cycles involving raccoons or woodrats, including a proper three-way trade-off (two independent parameters). Results indicate that selection favors oral transmission to raccoons but classical stercorarian transmission to woodrats even under the same predation rate, with vertical (congenital) transmission favored only when aligned with dominant oral transmission or (at trace levels) under a weak (convex) trade-off. [Copyright &y& Elsevier]

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Next year will be the one hundredth anniversary of Carlos Chagas’ discovery of a disease that continues to endanger the lives of a significant number of people in the Americas, despite major successes in controlling its transmission and recent achievements in experimental specific chemotherapy against its etiological agent, Trypanosoma cruzi [1]. Through its impact on worker productivity, premature disability, and death, Chagas disease accounts for 670,000 disability-adjusted life years (DALYs), making it the most noteworthy parasitic disease of the Americas [2]. Furthermore, not only does primary infection continue to endanger the lives of countless people in the region, but the chronic manifestations of Chagas disease also affect the livelihood of many individuals previously infected. As the trend for global migration increases, the scope of Chagas disease threatens to expand exponentially, from rural to urban areas and endemic to non-endemic regions [3].In this epidemiological scenario, a relatively new element in its transmission has been added, the oral transmission. First described in Brazil in 2005 when an outbreak caused several deaths, another 15 cases of the disease followed in Santa Catarina related to the sale and ingestion of sugarcane juice [4,5]. This pattern has been continuing, confirming that oral transmission is not only possible, but more common than previously thought [5]. Since the initial report in 2005, more than a dozen outbreaks of Chagas disease have been recorded in the northern Brazilian states of Para, Amazonas, and Amapa [6]. But now, a confirmed considerable and significant outbreak of Chagas disease in Caracas, Venezuela, also related to ingestion of contaminated beverages [7], further suggests that American Trypanosomiasis is a food-borne entity.One hundred twenty-eight positive cases were confirmed in the Venezuelan capital up to the last week of December 2007. All these cases were clustered in a municipality school [7]. From that total, 12 patients were hospitalized. Patients are receiving benznidazole, one of the approved drugs for the specific treatment of Chagas disease, particularly for acute forms cases like these. Investigations are ongoing at the school given the exposure of 956 individuals [7]. As a consequence of this outbreak, the Ministry of Health, in conjunction with other metropolitan public health, research and academic institutions, produced guidelines for the diagnosis, management and treatment of Chagas disease during the acute phase at health facilities [8].These ongoing outbreaks in Brazil and Venezuela should serve as a warning to public health authorities and infectious disease physicians about the possible emergence ofsimilar outbreaks related to food and beverages in other countries. Although diagnosis can be difficult because the clinical symptoms are sometimes unspecific, Chagas disease should be suspected particularly in endemic zones. In the case of the Caracas outbreak, this city is not endemic for this disease and fortunately the first case was quickly diagnosed through the finding of trypomastigotes in blood films from the first patient. It should be mentioned that in Venezuela a significant number of acute phase Chagas disease cases have been previously reported [9]. During the acute phase a chagoma, an area of inflammation at the site of inoculation, could be seen. If conjunctival inoculation occurs, the triad of conjunctivitis, periorbital edema, and preauricular lymphadenopathy (the Romaña sign) may occur. Systemic dispersion of multiplying parasites during the acute phase may be asymptomatic or may manifest as fever, tachycardia, malaise, lymphadenopathy, hepatosplenomegaly, edema,vomiting, diarrhoea, anorexia, and/or rash [1]. In the acute phase, parasitization of cardiac muscle and brain may cause acute myocarditis and meningoencephalitis, respectively, sometimes causing death [1]. These clinical features were seen in food-borne acute Chagas disease cases.For these reasons, awareness and knowledge of these epidemiological pattern changes should be raised continuously both in the biomedical literature and by the public health authorities in endemic countries and in those countries with migration-related risk for Chagas disease. Chagas syndrome is a neglected disease, but it has clearlynot disappeared.

Abstract: In 2006, Brazilian government received the international certificate of interruption of the vectorial transmission of Chagas'' disease. However, outbreaks reported in Brazilian Amazon rainforest bear a regular occurrence and represents a relevant regional epidemiological gauge. The wild life cycle of the Chagas'' disease transmission (i.e., triatomine-marsupial cycle) is present outside the previously reported endemic belt, ubiquitously, as infective triatomines can be demonstrated in Palm trees widespread all over the Amazon rainforest. As humans invade the rainforest, one is incidentally caught up and further becomes'' an active part of American trypanosomiasis wild life cycle. [Copyright &y& Elsevier]