Parasite community interactions: Trypanosoma cruzi and intestinal helminths infecting wild golden lion tamarins Leontopithecus rosalia and golden-headed lion tamarins L. chrysomelas (Callitrichidae, L., 1766).

The parasite prevalence and infection intensity in primate wild populations can be affected by many variables linked to host and/or parasite ecology or either to interparasite competition/mutualism. In this study, we tested how host sex, age, and place of origin, as well parasitic concomitant infections affect the structure of golden lion and golden-headed lion tamarins parasite community, considering Trypanosoma cruzi and intestinal helminths infection in these primates. A total of 206 tamarins from two Atlantic Coastal rain forest areas in Brazil were tested during 4 years for prevalence of T. cruzi infection and helminth prevalence. Three intestinal helminth groups showed high prevalences in both tamarin species: Prosthenorchis sp., Spiruridae, and Trichostrongylidae. An association between presence of T. cruzi infection and higher intestinal helminth prevalence was found in both tamarin species. Two explanations for this association seem to be plausible: (1) lower helminth-linked mortality rates in T. cruzi-infected tamarins and (2) lower elimination rates of helminths in such tamarins. A higher frequency of T. cruzi-positive blood cultures was significantly correlated to female tamarins and to the presence of Trichostrongylidae infection. The possibility of an increase in the transmissibility of T. cruzi and the three analyzed helminths in lion tamarins with concomitant infections is discussed.

Prevalence and intensity of intestinal helminths found in free-ranging golden lion tamarins (Leontopithecus rosalia, Primates, Callitrichidae) from Brazilian Atlantic forest.

Helminth identification and egg counts were performed in 316 fecal samples during 4 years in 199 golden lion tamarins (GLTs), Leontopithecus rosalia, from two Brazilian conservation units. Tamarin sex and age, area of occurrence and helminth co-infection were tested as potential factors that could affect helminth prevalence and egg shedding in host individuals. Three nematodes species were found at low prevalences but not in both conservation units: Ancylostomatidae (12%), Ascarididae (1%) and Tripanoxyuris minutus, an Oxyuridae (4%). Three other species had high prevalences and were found in both conservation units: one acanthocephalan, Oncicola sp. (30%), and two nematodes, Spiruridae (24%), and Trichostrongylidae (31%). These three latter helminths had distinct prevalences between the conservation units, probably due to differences in availability of helminth infective stages in each area. Prevalences were greater in females for all helminth species; this was especially the case for Oncicola sp. Sex and age differences in helminth prevalence may be associated with changes in sexual steroid levels that accompany age and reproductive status. Frequency of simultaneous infections by the two helminths considered most pathogenic (Oncicola and Trichostrongylidae) were statistically lower than expected; this may be related to: (i) higher tamarin death rate caused by the association; (ii) differences in exposure to helminth infective stages in the various areas of occurrence; (iii) and competition between these helminth species. All helminth species followed a negative binomial distribution, with stronger clumping occurring in Trichostrongylidae and in female GLTs. Distinct transmission strategies of Oncicola sp. and Spiruridae, in contrast with Trichostrongylidae, may partially explain the different clumping levels of these helminths in GLTs. Mean fecal egg counts of all helminths were not different between GLT sexes, ages or areas of occurrence. The three most common helminth species may be a threat to isolated or dense GLT populations.

Behavioral and ecological interactions between reintroduced golden lion tamarins ( Leontopithecus rosalia Linnaeus, 1766 ) and introduced marmosets ( Callithrix spp, Linnaeus, 1758 ) in Brazil's Atlantic Coast forest fragments

Callithrix jacchus e spp (micos estrela) tem sido introduzido no estado do Rio de Janeiro em áreas designadas para a reintrodução do Leontopithecus rosalia (mico leão dourado). Os objetivos deste estudo foram estimar a população de sagüis em dois fragmentos particulares, e caracterizar a interação entre as espécies. A densidade de sagüis (0.09 a/ha) foi maior que a de mico-leão (0.06 a/ha). O grau de associação entre mico-leão e o sagüi variou entre grupos e estações do ano (inverno= 61%, verão =35%). Foram observados sinais de competição durante o inverno quando a presença do mico estrela está associada a mudanças no forrageio do mico-leão e aumento de comportamentos territoriais. No verão, sinais de benefícios foram uma diminuição da vigilância por parte dos adultos de micos leões. Além disso, os micos leões foram observados se alimentando de goma proveniente dos buracos feitos pelos micos estrela. Estes resultados sugerem que o mico estrela é uma ameaça para a conservação do mico-leão, no entanto.