Effects of habitat fragmentation on wild mammal infection by Trypanosoma cruzi

Abstract

Expansion of human activities frequently results in habitat fragmentation, a phenomenon that has been widely recognized in the last decades as one of the major threats to world's biodiversity. The transformation of a continuous forest into a fragmented area results in a hyper-dynamic landscape with unpredictable consequences to overall ecosystem health. The effect of the fragmentation process on Trypanosoma cruzi infection among small wild mammals was studied in an Atlantic Rain Forest landscape. Comparing continous forest to fragmented habitat, marsupials were less abundant than rodents in the continuous landscape. An overall decrease in small wild mammal richness was observed in the smaller fragments. An anti-T. cruzi seroprevalence of 18% (82/440) was deteced by immunofluorescence assay. Moreover, this seroprevalence was higher in the fragmented habitat than in the continuous forest. According to the collected data, 3 main factors seem to modulate infection by T. cruzi in small wild mammals: (i) habitat fragmentation; (ii) biodiversity loss; (iii) increase of marsupial abundance in mammal communities. Furthermore, an extremely mild controlled infection by T. cruzi was detected since no patent parasitaemia could be detected in fresh blood samples, and no parasites were isolated by haemoculture.

A Survey of Small Mammals in the Atlantic Forest of the Northwestern Region of Rio De Janeiro State

“…Philander frenatus and M. nudicaudatus are mainly terrestrial marsupials, commonly observed in fragmented landscapes (Pinto et al 2009, Vieira et al 2009). Even species with arboreal habits, and thus relatively more susceptible to deforestation, such as M. incanus, M. (M.) paraguayana and G. microtarsus, have frequently been observed in small forest fragments (Olifiers 2002, Castro & Fernandez 2004, Pardini et al 2005, Vaz et al 2007). The low capture success of these marsupials as well as rodent species in this study may be a consequence of the high habitat disturbance, caused mainly by forest fragmentation in the study areas (Lumbreras et al 2004, Fundação SOS Mata Atlântica & INPE 2015.…”

New Sylvatic Hosts of Trypanosoma cruzi and Their Reservoir Competence in the Humid Chaco of Argentina: A Longitudinal Study

“…7,9,24,42 This separation is not complete because other DTUs have occasionally been found in opossums and armadillos. 4,7,23,43 The most likely local vectors of TcI and TcIII, as yet not identified conclusively, are Triatoma sordida and Panstrongylus geniculatus, respectively. Triatoma sordida is locally abundant and was the only bug species found infected with TcI 31 whereas P. geniculatus was found in local armadillo burrows.…”

“…Residual forest fragments act as a refuge for some host species. The effects of habitat fragmentation on disease prevalence vary with the specific host-parasite relationship, 23,54 and new foci of transmission may be created at intermediate levels of degradation. 23 Some of the main reservoir hosts of T. cruzi adapt easily to peridomestic rural environments where they maintain sizable numbers and high prevalence of infection with T. cruzi.…”

“…The effects of habitat fragmentation on disease prevalence vary with the specific host-parasite relationship, 23,54 and new foci of transmission may be created at intermediate levels of degradation. 23 Some of the main reservoir hosts of T. cruzi adapt easily to peridomestic rural environments where they maintain sizable numbers and high prevalence of infection with T. cruzi. The observed large infection prevalence in white-eared opossums and nine-banded armadillos combined with their rather large abundance in small forest fragments nearby peridomestic sites may facilitate parasite transmission, especially in disturbed areas.…”

“…22 Ongoing large-scale changes in land use and habitat fragmentation throughout Latin America may impact sylvatic transmission cycles in unforeseen ways, either reducing or increasing parasite prevalence. 19,23 Little is known about the structure and spatiotemporal dynamics of sylvatic transmission cycles of T. cruzi in the Gran Chaco. Few areas have been investigated in recent decades, usually through cross-sectional or convenience surveys; sampling efforts have focused on a limited number of species and environments, and identification of parasite DTUs from wild hosts has been sparse.…”