Acta Tropica 122 (2012) 164–167 Contents lists available at SciVerse ScienceDirect Acta Tropica jo ur nal homep age : www.elsevier.com/locate /actatropica Field assessment of Trypanosoma cruzi infection and host survival in the native rodent Octodon degus Carezza Botto-Mahan a,∗ , Antonella Bacigalupo b , Juana P. Correa b , Esteban Oda a , Aldo Solari c a Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile b Departamento de Ciencias Biológicas Animales, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile c Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile a r t i c l e i n f o Article history: Received 14 October 2011 Received in revised form 4 December 2011 Accepted 5 December 2011 Available online 13 December 2011 Keywords: Chagas disease Wild reservoir Host survivorship Trypanosoma cruzi Chile a b s t r a c t Chagas disease is a zoonosis caused by the flagellated parasite Trypanosoma cruzi and transmitted by triatomine insects to several mammalian species acting as reservoir hosts. In the present study, we assess T. cruzi-prevalence, survivorship and T. cruzi-infection rate of the endemic rodent Octodon degus from a hyper-endemic area of Chagas disease in Chile. Parasite detection is performed by PCR assays on blood samples of individuals captured in austral summer of 2010, and on non-infected individuals recaptured in 2011 as well as on new captures. Results show a high infection level in this species (up to 70%). Infected O. degus have the same chance of surviving to the next reproductive season as uninfected individuals, irrespective of sex. We suggest that O. degus, an abundant long-lived rodent with high dispersal capability, could be considered an important native reservoir of T. cruzi in the wild transmission cycle of Chagas disease in Chile. © 2011 Elsevier B.V. All rights reserved. Many infectious agents infect more than one host species, some of which may be considered infection reservoirs (Haydon et al., 2002); however, host species may have different relative importance to pathogen transmission (Brunner et al., 2008). In vector-borne diseases, the most important features in assessing reservoir competence are: (i) host infection prevalence, and (ii) host infectivity, i.e., infection transmission to a feeding vector (Brunner et al., 2008). Both these metrics can be difficult to quantify under natural conditions. Nevertheless, other parameters such as lifespan of the reservoir when infected, rate of infection, and probability of congenital transmission are not explicitly considered when assess- ing the potential competence of a reservoir and its effect on disease risk in humans. Chagas disease, considered one of many neglected tropical dis- eases, is a zoonosis caused by the flagellated parasite Trypanosoma cruzi, and transmitted by triatomine insects to several mam- malian species (Leslie, 2011). The protozoan T. cruzi multiplies and differentiates in the digestive tract of the insect vector, and infection of mammalian hosts occurs by contamination of mucous membranes with insect-infected faeces containing the metacyclic trypomastigote stage of the flagellate (Kollien and Schaub, 2000). In ∗ Corresponding author at: Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, P.O. Box 653, Santiago, Chile. Tel.: +56 2 978 7392; fax: +56 2 272 7363. E-mail address: cbotto@uchile.cl (C. Botto-Mahan). hyper-endemic areas of Chagas disease in Chile, the main wild vec- tor Mepraia spinolai can reach infection levels of up to 46%, and in native mammals 61% on average (Botto-Mahan et al., 2005; Rozas et al., 2007). Several of these mammalian species may act as reser- voir hosts because the infectious agent seems to be nonpathogenic (but see Haydon et al., 2002). The endemic Chilean caviomorph rodent Octodon degus (Octodontidae) is a slow-reproducing species with diurnal activ- ity that lives in large colonies of up to 100 individuals (Mu˜ noz and Yᘠnez, 2000). This abundant species is mainly found in semiarid and Mediterranean ecosystems, where it feeds on grasses, shrub leaves, and seeds (Previtali et al., 2009). Under field conditions, it shows an average lifespan of about 3 years, but in captivity it can live 6–8 years (Previtali et al., 2009). Recently, O. degus has become popular as a pet in several countries (Johnson-Delaney, 2006). Molecular evidence indicates that T. cruzi-prevalence in wild pop- ulations of this rodent ranges from 20 to 61%, probably depending on climatic conditions (Botto-Mahan et al., 2010). Under labora- tory conditions, wild caught T. cruzi-infected O. degus can survive for up to two years after field capture (Campos et al., 2010). Even though published studies are informative for some epidemiologi- cal descriptions of the wild transmission cycle of Chagas disease, no information is available about the effect of T. cruzi on survivorship of native mammal hosts under natural conditions. In the present study, we estimate infection prevalence, survivorship, and T. cruzi- infection rate of the reservoir O. degus from a hyper-endemic area of Chagas disease in Chile. 0001-706X/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.actatropica.2011.12.003