21 research outputs found
Molecular epidemiology of domestic and sylvatic Trypanosoma cruzi infection in rural northwestern Argentina
Genetic diversity of Trypanosoma cruzi populations and parasite transmission dynamics have been well documented throughout the Americas, but few studies have been conducted in the Gran Chaco ecoregion, one of the most highly endemic areas for Chagas disease, caused by T. cruzi. In this study, we assessed the distribution of T. cruzi lineages (identified by PCR strategies) in Triatoma infestans, domestic dogs, cats, humans and sylvatic mammals from two neighbouring rural areas with different histories of transmission and vector control in northern Argentina. Lineage II predominated amongst the 99 isolates characterised and lineage I amongst the six isolates obtained from sylvatic mammals. T. cruzi lineage IIe predominated in domestic habitats; it was found in 87% of 54 isolates from Tr. infestans, in 82% of 33 isolates from dogs, and in the four cats found infected. Domestic and sylvatic cycles overlapped in the study area in the late 1980s, when intense domestic transmission occurred, and still overlap marginally. The introduction of T. cruzi from sylvatic into domestic habitats is likely to occur very rarely in the current epidemiological context. The household distribution of T. cruzi lineages showed that Tr. infestans, dogs and cats from a given house compound shared the same parasite lineage in most cases. Based on molecular evidence, this result lends further support to the importance of dogs and cats as domestic reservoir hosts of T. cruzi. We believe that in Argentina, this is the first time that lineage IIc has been isolated from naturally infected domestic dogs and Tr. infestans.Fil: Cardinal, Marta Victoria. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Lauricella, Marta A.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C.G. Malbrán”. Instituto Nacional de Parasitología “Dr. M. Fatala Chabén”; ArgentinaFil: Ceballos, Leonardo A.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Lanati, Leonardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Marcet, Paula Lorena. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Levin, Mariano Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Kitron, Uriel D.. Emory University; Estados UnidosFil: Gurtler, Ricardo Esteban. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Schijman, Alejandro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin
Natural Trypanosoma cruzi infection in dogs of endemic areas of the Argentine Republic
Distribution and pathogenicity of Trypanosoma cruzi isolated from peridomestic populations of Triatoma infestans and Triatoma guasayana from rural Western Argentina
Epidemiological role of humans, dogs and cats in the transmission of Trypanosoma cruzi in a central area of Argentina
Direct molecular identification of Trypanosoma cruzi Discrete Typing Units in domestic and peridomestic Triatoma infestans and Triatoma sordida from the Argentine Chaco
We assessed the distribution of Trypanosoma cruzi Discrete Typing Units (DTUs) in domestic and peridomestic Triatoma infestans and Triatoma sordida specimens collected in a well-defined rural area in Pampa del Indio, northeastern Argentina. Microscopically-positive bugs were randomly selected with a multi-level sampling design, and DTUs were identified using direct PCR strategies. TcVI predominated in 61% of 69 T. infestans and in 56% of 9 T. sordida. TcV was the secondary DTU in T. infestans (16%) and was found in 1 T. sordida specimen (11%). Three T. sordida (33%) were found infected with TcI, a DTU also identified in local Didelphis albiventris opossums. Mixed DTU infections occurred rarely (5%) and were detected both directly from the bugs' rectal ampoule and parasite cultures. The identified DTUs and bug collection sites of T. infestans were significantly associated. Bugs infected with TcV were almost exclusively captured in domiciles whereas those with TcVI were found similarly in domiciles and peridomiciles. All mixed infections occurred in domiciles. TcV-infected bugs fed more often on humans than on dogs, whereas TcVI-infected bugs showed the reverse pattern. T. sordida is a probable sylvatic vector of TcI linked to D. albiventris, and could represent a secondary vector of TcVI and TcV in the domestic/peridomestic cycle.Fil: Maffey, L.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Cardinal, Marta Victoria. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ordóñez Krasnowski, P.C.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Lanati, L. A,. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Lauricella, M. A.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; ArgentinaFil: Schijman, Alejandro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gurtler, Ricardo Esteban. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Immunodiagnosis of Trypanosoma cruzi (Chagas' Disease) Infection in Naturally Infected Dogs
This study reports on the standardization of an enzyme-linked
immunosorbent assay (ELISA) for detecting specific antibodies
anti-Trypanosoma cruzi in naturally infected dogs. Sera from 182
mongrel dogs of all ages residing in four rural villages in Santiago
del Estero, Argentina, were collected in November 1994 and preserved in
buffered neutral glycerin. All sera were tested by indirect
hemagglutination test (IHAT), indirect immunofluorescence test (IFAT),
and ELISA using the flagellar fraction of T. cruzi as antigen. Dog sera
from an area without vectorial transmission were used to calculate
ELISA specificity and cut-off value. Eighty-six percent of sera had
concordant results for all tests. All sera reactive for IHAT and IFAT
were also reactive for ELISA, except in one case. Sera tested by ELISA
when diluted 1:200 allowed a clearer division between non-reactive and
reactive sera than when 1:100 with greater agreement among serologic
techniques. The specificity of ELISA was 96.2%. Among 34 adult dogs
with a positive xenodiagnosis, sensitivity was 94% both for ELISA and
IFAT. ELISA is the first choice for screening purposes and one of the
pair of techniques recommended for diagnostic studies in dog
populations
Distribution and pathogenicity of Trypanosoma cruzi isolated from peridomestic populations of Triatoma infestans and Triatoma guasayana from rural Western Argentina
We assessed the distribution of Trypanosoma cruzi infection in
peridomestic triatomines collected manually at a district-wide scale in
rural villages around Olta, Western Argentina, and typed the isolated
strains according to their pathogenicity to laboratory mice. Of 1623
triatomines examined, only 14 (0.9%) were infected with T. cruzi based
on microscopical examination of feces. The prevalence of T. cruzi
infection was 0.8% in Triatoma infestans, 2.3% in T. guasayana, and nil
in T. garciabesi, T. platensis, and T. eratyrusiformis. Local
transmission occurred in kitchens, store-rooms and goat corrals or
nearby, though at very low levels. T. cruzi was detected by at least
one parasitological method in 11 (79%) of 14 microscope-positive bugs.
Hemoculture was the most sensitive method (67%) followed by culture of
organ homogenates, histopathology or xenodiagnosis of inoculated
suckling mice (55-58%), and culture of microscope-positive bug feces
(46%). The evidence suggests that most of the isolated T. cruzi
strains would be myotropic type III. Our study establishes for the
first time that peridomestic, microscope-positive T. guasayana nymphs
were actually infected with T. cruzi, and may be implicated as a
putative secondary vector of T. cruzi in domestic or peridomestic
sites