Natural Trypanosoma cruzi infection in dogs of endemic areas of the Argentine Republic

Abstract

SUMMARYThe population dynamics and the prevalence of chagasic infection of 352 dogs living in 108 rural houses infested by triatomines were studied. The region was divided into three sections according to increasing distances to an urban area. Each animal was identified by means of its particular characteristics and built, and its owners gave information about its habits. By means of xenodiagnosis, serology and ECG studies, prevalences of infection, parasitological-serological correlation, percentage of altered electrocardiographic outlines and percentage of houses with parasitemic dogs, were determined.The rural area showed a characteristic T. cruzi infection pattern and differences in the canine population parameters with respect to the other areas were observed: a higher proportion of puppies than adult dogs, a more sedentary population, higher prevalences of infection, as measured by xenodiagnosis, in dogs, and the highest proportion of bedroom insects infected with T. cruzi.It is assumed that the sedentary characteristics of the human population in that rural area impinge in the blood offer to the triatomine population, and the rúgh percentage of parasitemic dogs of the area, contribute to the rise of "kissing ougs" infected with T. cruzi found in bedrooms.

Soroprevalência da infecção por Trypanosoma cruzi em cães de uma área rural do Estado de Mato Grosso do Sul

“…Vári-os autores (Malchiodi et al 1994, Umezawa & Silveira 1999 alertam que os métodos sorológicos são considerados importantes ferramentas no diagnóstico da infecção chagásica, uma vez que os níveis de anticorpos permanecem por décadas, porém, em humanos, a reação cruzada com a leishmaniose em áreas onde as doenças se sobrepõem prejudica a especificidade dos testes convencionais. Em um estudo utilizando cães (Lauricella et al 1989), foi demonstrada especificidade de 96,2% com ELISA e o teste foi recomendado para a triagem nessa espécie, contudo, é importante ressaltar que tal estudo foi conduzido em área livre de leishmaniose canina.…”

“…Dos 10 cães sororeagentes tanto para T. cruzi quanto para Leishmania, dois foram submetidos ao xenodiagnóstico clássico e seis foram submetidos ao exame parasitológico direto. A soroprevalência da infecção por Trypanosoma cruzi neste estudo foi muito superior a observada em outra área do Estado (Silva 1979), que detectou apenas 3% de positividade através da técnica de IFI, aproxima-se da observada na Argentina (Lauricella et al 1989) e na Costa Rica (Montenegro et al 2002) e confirma a infecção chagásica nos cães de Mato Grosso do Sul.…”

Reservoir host competence and the role of domestic and commensal hosts in the transmission of Trypanosoma cruzi

“…The prevalence of xenodiagnosis-positive dogs and their infectiousness either were ageindependent or declined marginally or significantly with age ( Figure 1B) (Enriquez et al, 2014;Gürtler et al, 2007a;Gürtler et al, 1998bGürtler et al, , 1996aGürtler et al, , 1992aGürtler et al, , 1986bLauricella et al, 1989). The potential contribution of pups to bug infection (P a ) was approximately 50% greater than that of the older age groups combined (Gürtler et al, 1996a).…”

“…Electrocardiographic surveys of infected dogs from endemic rural areas evidenced either a very low frequency of abnormalities or unspecific ones (Lauricella et al, 1989;Ruiz et al, 1985) or significant cardiac alterations (Cruz-Chan et al, 2009). Numerous fatal cases of young dogs (mainly pure-bred) were recorded in veterinary clinics from southern USA (Barr, 2009;Kjos et al, 2008;Williams et al, 1977).…”

Household prevalence of seropositivity for Trypanosoma cruzi in three rural villages in northwest Argentina: environmental, demographic, and entomologic associations.

“…All serologic tests were carried out at the National Chagas Institute (Buenos Aires, Argentina) following standard procedures. 22,23 Seroreactivity for T. cruzi of human sera was demonstrated by titers of 1:32 or greater for the indirect hemagglutination test (IHA) and the immunofluorescent antibody test (IFAT), and by an optical absorbance of 0.2 or greater by an ELISA. Seroreactivity for T. cruzi of dog sera was demonstrated by IHA and IFAT titers of 1:16 or greater and ELISA readings of 0.2 or greater in 1992.…”