Current transmission and control of Chagas’ Disease and leishmaniasis in Argentina. Sosa-Estani S. XX Annual Meeting of the Brazilian Society of Protozoology. XXXI Annual meeting on Basic Research in Chagas´ Disease.

SOSA-ESTANI S

Caxambú, Minas Gerai, Brazil

Congreso; XX Annual Meeting of the Brazilian Society of Protozoology. XXXI Annual meeting on Basic Research in Chagas´ Disease.; 2004

Soc Bras Protzoología

Chagas’ disease and leishmaniasis are the two leading endimic diseases transmitted by vectors in Argentina. A program with a nationwide impact for the control of Chagas disease began in Argentina in 1962, and in 1999 an interinstitutional coordinating program at the national level was formed with the aim of coordinating strategies for the control of leishmaniasis transmission. Remarkably has been the progress made over the past 15 years. The control of both vectorial transmission through T. infestants and T. cruzi transmission through blood transfusion has been consolidated. Furhter, the control of congenital transmission as well as etiologic diagnosis and treatment for the young population were implemented nationwide. In 2003, the infestation of household for triatomines  was 3.1 % [0.0% - 39.4%].  Although the interruption of the vectorial transmission in 4 provinces was achieved in 2002, current rates still indicate the existance of high risk areas for infestation, as evinced by the 18 reported cases of vectorial transmission in 2003. Intervention to mitigate vectorial transmistion in the affected areas was intensified. Further, the control of blood for transfusion indicates a prevalence of 4,1% of infection among blood donors. Considering the high risk of accidents through this transmission route, it is necessary to  sustain this strategie. Screening of pregnant women increases year after year. A number of 185,362 women were controlled in 2003, and the prevalence of infection was 5.5 % [0,7% - 14,0%]. The current estimate of new cases of Chagas’ disease congenitally transmitted range from 800 to 1,700. In the future the congenital transmission will be the only infection route that will cause new cases, when the complete control of vectorial transmission is achieved. The set of actions implemented has shown its efficacy in the reduction of the prevalence in the infant population. In 2003, 14,541 serologic tests were performed in children aged 15 years or younger. Prevalence of infection was 3.4 % in areas with recently implemented surveillance and 0.8 % in areas where surveillance already existed. Clinical research conducted in the earlier 1990s allowed us to incorporate in a programatic fashion etiological diagnosis and treatment  in the infected infant and young population.  Tegumentary leishmaniasis (TL) with expression Cutaneous (CL) and Muco-cutaneous (MCL) in Argentina is an endemic disease with sporadic outbreaks of epidemic stemming from different reasons. Its clinical manifestation is similar in all endemic provinces. The main species of parasite isolated has been the Leishmania (Viannia) braziliensis. The low ocurrance of mucosal forms of the disease would be attributable to the earlier diagnosis and timely treatment offered by the health system. The effective human-vector contact ocurrs in the wild environment as well as in peridomestic and periurban sectors. The former takes places during logging or foresting activities, fishing, or hunting, which is frequent in the northwest region of the country. The latter,  is more connected with peoples’ proximity to residual vegetation, causing periurban outbreak, as can be seen in the northeast region of Argentina. Potential vectors, as the Lutzomyia neivai, are abundant in peridomestic area near closed secundary vegetation environement (modified) and the population dynamics is associated with climate changes. Other species, such as the Lu. migonei, Lu. Shannoni and Lu. cortelezzii, could be responsible for the transmission cycle observed in the northwest region. In the northeast, this role could be attributed to Lu. whitmani, Lu. shannoni, Lu. cortelezzii, Lu. Quinquefer y Lu. migonei. The determinants of transmission analyzed varied according to the different study regions. Parallel to the system of cases’ detection for early treatment, we propose the design of an entomologic surveillance in those critical areas during the period of endemic transmission. This porpuosal is based on a barrier espatial interventions when vectors´ abundance show high risk of epidemic outbreak. 748 cases of tegumentary leishmaniasis were notified in Argentina in 2002 and 348 cases in 2003. In the light of the recent ocurrance of visceral leishmaniasis transmission in Paraguay, a field study was carried out in Clorinda (a village in the Argentinean Province of Formosa, which is bounded by Asunción del Paraguay) to evaluate risk factors. Preliminar data confirmed the presence of  the potential vector (L. longipalpis), but no dispersion data, was still obtained. Human or canine migration implying risk was observed. On the other hand, this piece of research has not yet demostrated evidence of autochthonous transmission. Although LV canine (imported) was only detected,  no human cases were observed.  Further research has been planned to monitor this scenario. Community involvement for the control of these endemic diseases will be crutial to attain the sustainability of the control strategies implemented.