Roberto Salvatella

Interruption of vector transmission by native vectors and “the art of the possible”

In a recent article in the Reader’s Opinion, advantages and disadvantages of the certification processes of interrupted Chagas disease transmission (American trypanosomiasis) by native vector were discussed. Such concept, accepted by those authors for the case of endemic situations with introduced vectors, has been built on a long and laborious process by endemic countries and Subregional Initiatives for Prevention, Control and Treatment of Chagas, with Technical Secretariat of the Pan American Health Organization/World Health Organization, to create a horizon target and goal to concentrate priorities and resource allocation and actions. With varying degrees of sucess, which are not replaceable for a certificate of good practice, has allowed during 23 years to safeguard the effective control of transmission of Trypanosoma cruzi not to hundreds of thousands, but millions of people at risk conditions, truly “the art of the possible.”

Andean subregional Chagas disease area and the Andean Initiative of Chagas Disease

The Andean subregional Chagas disease area and theAndean initiative of Chagas disease consist of the asso-ciation of Peru, Ecuador, Colombia, and Venezuela withtheir own and particular characteristics:1. extensive area distributed in a broad latitude;2. important echo-biological diversity;3. biogeographically variables due to diverse alti-tude and latitude;4. different epidemiological situations of Chagasendemic disease;5. socioeconomic-cultural diversity;6. ethnic diversity;7. different structures and characteristics of peri andintradomiciliary areas;8. different vectors implied in the transmission ofTrypanosoma cruzi;9. various degrees of development and continuity ofthe control/surveillance of Chagas disease.The initiative, created in 1997, has gotten around dis-continuity periods but has served as a support of develop-ment of the prevention, control, surveillance, and care ofChagas disease, that the member countries have fulfilled.The proposed control against the vector of Chagasdisease has been based on a proposal that countries de-veloped in the Initiative, centered in actions that priori-tize the concept of “risk”.Some species of triatomines of the subregion, poin-ted out as vectors of the greatest epidemiological im-portance, are prone of “elimination”, such as:Rhodnius prolixus: Colombia and VenezuelaTriatoma dimidiata and Rhodnius ecuadoriensis:Ecuador.Rhodnius ecuadoriensis and Triatoma infestans: Peru.This may be possible to their condition of speciesclosely associated to anthropic constructions.Other species of vector importance, given their “indig-enous” condition with presence in nature, only makes itpossible to assume a control of its household presence.Wild populations of R. prolixus, R. ecuadoriensis,and T. dimidiata correspond to studies in specific areasand should be subject to entomological surveillance.With regard to medical care – with diagnosis, man-agement, and treatment of the infected/Chagas disease –, itshould be worked a great deal so that national health sys-tems fortify theirs capabilities, departing as an exampleof a better quantification of their prevalences, morbid-ity, and mortality, and of a clear development of the as-pects of treatment with regard to indication, opportu-nity, access, and availability.The objectives of the Andean Initiative of ChagasDisease are the control of the vector-borne transmis-sion of Chagas disease and the control of the transfu-sion transmission of Chagas disease.It seems to be a subject to consider in the future theoutlining of more specific objectives in order.The Andean Initiative of Chagas disease and/or someof its members have counted up to date with technicalcooperation of major interest, such as: CDIA/EC; ECLAT;CIDA (Canada); TDR/WHO; and the Technical Secre-tariat of PAHO.A characteristic of significance in the four membercountries is their double membership to endemic op-portunities geo-epidemiologist of Chagas disease:Andean and Amazon.There exists potential for groups and institutions ofimportance in the area of research, that are capable offormulating contributions to the prevention, control,surveillance, and care of Chagas disease, as effectivelyhave carried them out.This subregional space is acquiescent of a greaterdevelopment of actions on Chagas disease and of tech-nical and horizontal international cooperation amongmember countries, better organized and coordinated, inorder to strengthen the control measures.The technical cooperation possibilities are timely andrelevant appropriate as they may possible the following:(1) training applied to the control and care; (2) techno-logical transfer of validated schemes of prevention, con-trol, and surveillance; (3) practical research and appliedin field for the purpose of control; (4) the developmentof mass communication, in favor of installing in betterform to Chagas disease, among the subjects of the healthagenda of the countries; (5) the utilization of the Websportal suitable for: (a) dissemination of regular meetingreports; (b) dissemination of reports on workshops andtechnical forums; (c) dissemination of work manuals incontrol and attention; (d) rendering operational coursesvirtual in control and attention; (6) promote horizontaltechnical cooperation among services and institutes ofthe member countries; (7) increase international evalu-ation systems of land, through visits of commissions ofindependent specialists; (8) the development of tests ofquality control in diagnosis among the countries and cen-ters of excellence; (9) standardize criteria for the treat-ment and follow-up of the infected patient.

Hallazgo de Triatoma platensis Neiva, 1913 (Hemiptera, Triatominae) en el estado brasileño de "Rio Grande do Sul"

Triatoma platensis, an ornitophilic species, found in Argentina, Bolivia, Paraguay and Uruguay is reported for the first time in Brazil. It was found in the county of Uruguaiana (Rio Grande do Sul) in nests of Anumbius annumbi (Vieillot, 1817) (Passeriformes, Furnariidae) where it cohabited with cricetids belonging to the species Orizomys flavescens. None of the seven individuals collected were infected by Trypanosoma cruzi.Triatoma platensis, an ornitophilic species, found in Argentina, Bolivia, Paraguay and Uruguay is reported for the first time in Brazil. It was found in the county of Uruguaiana (Rio Grande do Sul) in nests of Anumbius annumbi (Vieillot, 1817) (Passeriformes, Furnariidae) where it cohabited with cricetids belonging to the species Orizomys flavescens. None of the seven individuals collected were infected by Trypanosoma cruzi.

Seroprevalencia de la infección por Trypanosoma cruzi en escolares de seis y doce años de edad de tres departamentos endémicos de Uruguay

The last national survey on seroprevalence of T. cruzi human infection in Uruguay, showed a 3.4% in adults from endemic areas. Since 1983, antivectorial actions of the control program have been carried out continually. In consequence, household infestation by Triatoma infestan, the main vector of T. cruzi in Uruguay, decreased in all endemic areas and was completely eliminated in some of them. The objectives of the present work are to evaluate the new seroepidemiological situation. A representative sampling of rural and urban population was undertaken, to include six and twelve year-old school children from three departments: Artigas, Rivera and Tacuarembo. The whole sample included 4,722 school children, evaluated by the indirect immunofluorescence (IFI) test for Chagaś disease. The seroprevalence of T. cruzi infection in the six year-old group was 0.3% in Artigas, 0.6% in Rivera and 1.0% in Tacuarembo. The seropositive children with seropositive mothers support the possible congenital transmission.

Transmisión vertical del Trypanosoma cruzi. Consideraciones y recomendaciones acordadas en la Mesa Final de laJornada

Once vectorial transmission of Trypanosoma cruzi disappeared and transfusion-transmission was controlled, vertical infection constitutes the only relevant transmission mode in our country. The fact that there are chronically infected adults leads to the risk of congenital Chagas Disease, which may occur in more than one generation with the same ascendancy. Indeed, constant human migration results in the risk of congenital transmission being present throughout the country, thus exceeding the endemic areas initially defines by the presence of domicile vector. Therefore, vertical transmission of Trypanosoma cruzi does not respect borders or generation boundaries and its sub-diagnosis has resulted in the emergence of several cases. Thus, reality leads to the remarks and recommendations that follow below, with the purpose of promoting the right control of this parasitosis.La rabia es una zoonosis de causa viral que provoca una encefalitis aguda y progresiva invariablemente fatal, causante de unas 60.000 muertes anuales. La mayoría de los casos humanos se reportan en África y Asia, pero su distribución es mundial. Se bien se trata de una enfermedad en vías de eliminación en las Américas, ha habido un resurgimiento con nuevas áreas y países afectados en los últimos años. En áreas endémicas los casos humanos están relacionados con mordeduras por perros infectados, mientras que en el resto de los países se asocia a mordeduras de animales silvestres. Luego de las mordeduras, el uso apropiado de la profilaxis posexposición es universalmente efectiva. Por lo tanto, para disminuir la carga global de rabia humana, es fundamental el control de la rabia canina y la expansión de la disponibilidad de profilaxis. En Uruguay, si bien se eliminó la rabia humana en la década de 1960, desde el año 2007 asistimos a una situación epidemiológica compleja con la reintroducción de la rabia animal vinculada a murciélagos. Esto debe poner en alerta a la comunidad médica y veterinaria para evitar el resurgimiento de la rabia humana. Se necesita del esfuerzo conjunto de la medicina humana, veterinaria, de la población y del gobierno a través de políticas públicas con el fin de mantener la vigilancia epidemiológica, actuar sobre el control de la población de perros y aplicar medidas de profilaxis en humanos luego de la mordedura de animales. En la presente revisión se describe la situación en Uruguay, la presentación clínica de esta enfermedad y las indicaciones de profilaxis.