INVESTIGADORES
CARDINAL Marta Victoria
congresos y reuniones científicas
Título:
Are domestic and sylvatic Trypanosoma cruzi transmission cycles overlapped in the humid Argentinean Chaco?
Autor/es:
CARDINAL, MV; OROZCO MM; ENRIQUEZ GF,; MAFFEY L; SARTOR P; MACCHIAVERNA NP; SCHIJMAN AG; GURTLER RE
Lugar:
Porto de Galhinas
Reunión:
Congreso; 2nd International Congress on Pathogens at the Human-Animal Interface (ICOPHAI): One Health for Sustainable Development.; 2013
Resumen:
Trypanosoma cruzi transmission cycles include a wide diversity of mammal hosts, triatomine bug species
and parasite genotypes (called Discrete Typing Units, DTUs) encompassing both domestic and sylvatic
environments. Throughout the Americas, domestic and sylvatic transmission cycles show different
degrees of overlapping. Could the introduction of sylvatic T. cruzi parasites pose a threat to domestic
transmission control efforts in areas where the cycles have had little overlap historically? To study the
structure of T. cruzi transmission cycles we assessed the distribution of parasite DTUs (identified by PCR
strategies) in (peri)domestic Triatoma infestans and Triatoma sordida, domestic dogs and cats, humans
and sylvatic mammals in the humid (Eastern) Argentinean Chaco. TcVI predominated in 61% of 69
(peri)domestic T. infestans and in 56% of 9 T. sordida, and was identified in 84% of 44 dogs and in 83%
of 12 cats. TcV was the secondary DTU identified in the (peri)domestic environment. In humans,
preliminary results found TcI infections and incomplete DTU identifications (due to very low
parasitemia) indicating either TcII or TcV or TcVI infections. Among infected sylvatic mammals, all
(n=12) Didelphis albiventris (white-eared opossums) were infected with TcI, whereas all armadillos (12
Dasypus novemcinctus, 1 Chaetophractus vellerosus, and 1 Tolypeutes matacus) were infected with TcIII,
implying two distinct sylvatic cycles. These DTUs were absent in (peri)domestic T. infestans but three
TcI-infected T. sordida were found in peridomestic ecotopes and two TcIII-infected dogs were recorded,
suggesting a probable link with local sylvatic transmission. The household distribution of T. cruzi DTUs
showed that bugs, dogs and cats from a given house compound shared the same parasite genotype in most
cases. This result lends further support to the importance of dogs and cats as domestic reservoir hosts of
T. cruzi. The introduction of T. cruzi from sylvatic into domestic habitats would occur very rarely in the
current epidemiological context of rural communities in the Humid Chaco area confirming previous
studies in communities under sustained vector surveillance in the Dry Argentinean Chaco. However,
ongoing large-scale changes in land use and habitat fragmentation in the Argentinean Chaco may impact
sylvatic transmission cycles, modify host and parasite distributions and result in a higher risk of
transmission in new suitable habitats.