[Contribution to knowledge of reservoirs of Trypanosoma cruzi (Chagas, 1909) in Corrientes Province, Argentina]

Parasites and Other Infectious Agents in Non-human Primates of Argentina

Purpose of Review

In Argentina, there are five non-human primate (NHP) species: Sapajus nigritus cucullatus, Sapajus cay, Alouatta caraya, Alouatta guariba clamitans, and Aotus azarae. All of them inhabit protected and non-protected areas and face severe threats due anthropization. We aim to summarize the information available about parasites and infectious diseases of these NHPs and suggest further research on primate diseases in Argentina.

Recent Findings

NHPs of Argentina are hosts of several parasites and pathogens important for conservation as well as public health. Alouatta species are lethally susceptible to yellow fever virus, which makes them suitable health sentinels of possible outbreaks. For other primate species, few parasite surveys have been carried out.

Summary

Assessing the presence of infectious diseases and long-term surveillance on NHP allow the development of strategies to help in the early detection of pathogens that may threat public health. Increasing the knowledge about parasites and infectious diseases and their consequences in NHP of Argentina is needed, considering a One Health approach.

First report of Sapajus cay naturally infected by Trypanosoma cruzi in San Pedro Department, Paraguay

To verify the occurrence of natural Trypanosoma cruzi infection in non-human primates from a rural endemic area of the east region of Paraguay, xenodiagnosis was performed in 35 animals belonging to two species. For genotyping and T. cruzi discrete typing unit (DTU) assignment, a combination of four markers was used, including amplification products of the small (18S) and large (24Sα) subunits of ribosomal ribonucleic acid gene, the intergenic region of mini-exon gene and the heat shock protein 60 Eco-RV polymerase chain reaction-restriction fragment length polymorphism (HSP60/EcoRV-PCR-RFLP). One specimen of Sapajus cay was found positive and infected by the DTU TcII. This result constitutes the first record of natural T. cruzi infection in a sylvatic monkey in Paraguay, harbouring a DTU associated with severe Chagas disease in humans.

Molecular characterization of trypanosomatid infections in wild howler monkeys (Alouatta caraya) in northeastern Argentina

The transmission of Trypanosoma cruzi by vectors is confined to the Americas, and the infection circulates in at least two broadly defined transmission cycles occurring in domestic and sylvatic habitats. This study sought to detect and characterize infection by T. cruzi and other trypanosomes using PCR strategies in blood samples from free-ranging howler monkeys, Alouatta caraya, in the northeastern Argentina. Blood samples were collected at four sites with variable levels of habitat modification by human activity. PCR was conducted using primers for kinetoplast DNA, satellite DNA and ribosomal DNA of the trypanosomatid parasites. Ribosomal and satellite DNA fragments were sequenced to identify the trypanosomatid species and to characterize the discrete typing units (DTUs) of T. cruzi. Overall, 46% (50/109) of the howlers were positive according to the kDNA-PCR assay, but only 7 of the howlers were positive according to the SatDNA-PCR protocol. We sequenced the amplicons of the satellite DNA obtained from five specimens, and the sequences were 99% and 100% similar to T. cruzi. A sequence typical of DTU T. cruzi I was found in one howler monkey from the "remote" site, while sequences compatible with DTUs II, V, and VI were found in howlers from the "remote", "rural" and "village" sites. We detected 96% positive samples for RibDNA-PCR, 9 of which were sequenced and displayed 99% identity with Trypanosoma minasense, while none showed identity with T. cruzi. The results demonstrated the presence of T. cruzi and a species closely related to T. minasense in blood samples from free-ranging A. caraya, belonging to different T. cruzi DTUs circulating in these howler monkey populations. The results obtained in this study could help evaluate the role of A. caraya as a reservoir of T. cruzi in regions where Chagas disease is hyper-endemic and where the human-wildlife interface is increasing.

First finding of Trypanosoma cruzi II in vampire bats from a district free of domestic vector-borne transmission in Northeastern Argentina

Establishing the putative links between sylvatic and domestic transmission cycles of Trypanosoma cruzi, the etiological agent of Chagas disease, is of public health relevance. We conducted three surveys to assess T. cruzi infection in wild mammals from a rural and a preserved area in Misiones Province, Northeastern Argentina, which had recently been declared free of vector- and blood-borne transmission of human T. cruzi infection. A total of 200 wild mammals were examined by xenodiagnosis (XD) and/or polymerase chain reaction (PCR) amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR). The overall prevalence of T. cruzi infection was 8%. Nine (16%) of 57 Didelphis albiventris opossums and two (7%) of 29 Desmodus rotundus vampire bats were positive by both XD and kDNA-PCR. Additionally, one D. rotundus positive for T. cruzi by kDNA-PCR tested positive by satellite-DNA-PCR (SAT-DNA-PCR). The T. cruzi-infected bats were captured indoors and in the yard of a vacant dwelling. All D. albiventris were infected with TcI and both XD-positive D. rotundus by TcII. Fifty-five opossum cubs within the marsupium were negative by XD. The mean infectiousness to the vector was 62% in D. albiventris and 50% in D. rotundus. Mice experimentally infected with a parasite isolate from a vampire bat displayed lesions typically caused by T. cruzi. Our study documents the presence of the genotype TcII in a sylvatic host for the first time in Argentina, and the occurrence of two transmission cycles of T. cruzi in a district free of domestic vector-borne transmission.

The sylvatic transmission cycle of Trypanosoma cruzi in a rural area in the humid Chaco of Argentina

Little is known about the sylvatic transmission cycle of Trypanosoma cruzi in the Gran Chaco ecoregion. We conducted surveys to identify the main sylvatic hosts of T. cruzi, parasite discrete typing units and vector species involved in Pampa del Indio, a rural area in the humid Argentinean Chaco. A total of 44 mammals from 14 species were captured and examined for infection by xenodiagnosis and polymerase chain reaction amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR). Ten (22.7%) mammals were positive by xenodiagnosis or kDNA-PCR. Four of 11 (36%) Didelphis albiventris (white-eared opossums) and six of nine (67%) Dasypus novemcinctus (nine-banded armadillos) were positive by xenodiagnosis and or kDNA-PCR. Rodents, other armadillo species, felids, crab-eating raccoons, hares and rabbits were not infected. Positive animals were highly infectious to the bugs that fed upon them as determined by xenodiagnosis. All positive opossums were infected with T. cruzi I and all positive nine-banded armadillos with T. cruzi III. Extensive searches in sylvatic habitats using 718 Noireau trap-nights only yielded Triatoma sordida whereas no bug was collected in 26 light-trap nights. Four armadillos or opossums fitted with a spool-and-line device were successfully tracked to their refuges; only one Panstrongylus geniculatus was found in an armadillo burrow. No sylvatic triatomine was infected with T. cruzi by microscopical examination or kDNA-PCR. Our results indicate that two independent sylvatic transmission cycles of T. cruzi occur in the humid Chaco. The putative vectors of both cycles need to be identified conclusively.

Differential reactivity of serum immunoglobulins from Brazilian wild mammals to staphylococcal A and streptococcal G proteins

Human pathogens have evolved to infect vertebrate hosts other than human beings without causing symptoms of the disease, thus permitting them to complete their life cycle and to develop into infectious forms. The identification and management of infected animals are alternatives to control dissemination of the disease and to prevent human illness. In the current study, the potential use of staphylococcal A or streptococcal G proteins was evaluated with enzyme-linked immunosorbent assays (ELISAs) for seroepidemiological studies. Sera were collected from animals that were representative of 23 different Brazilian wild mammals. A high protein A binding rate was observed in all animals, except for the orders Didelphimorphia, Artiodactyla, and Rodentia, in which affinity was medium or low. Affinity for streptococcal G protein was higher in animals of the order Artiodactyla, whereas no streptococcal G protein binding was observed in samples obtained from felines (order Carnivora). Bacterial protein binding to mammalian immunoglobulins was confirmed by immunoblotting. The results suggest that secondary detection systems should be better investigated in ELISA protocols before their implementation in seroepidemiological studies involving wild mammals.

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.

Clinical, biochemical, and electrocardiographic aspects of Trypanosoma cruzi infection in free-ranging golden lion tamarins (Leontopithecus rosalia)

BACKGROUND

Wild golden lion tamarins from the Biological Reserve of Poço das Antas, Rio de Janeiro, Brazil, have high prevalence of Trypanosoma cruzi infection leading us to clinically assess the disease in this endangered species.

METHODS

34 tamarins were sampled for the presence of T. cruzi infection (through serology) and clinical evaluation (electrocardiography, blood counts and biochemical analysis).

RESULTS

32% of the sampled tamarins were T. cruzi positive, 45% of these displayed cardiac abnormalities. Main cardiac abnormality in infected tamarins was T wave low voltage; R wave low voltage and V3S wave high voltage were also found. The tamarins displaying T wave low voltage had high proportion of seric cardiac creatine kinase. Seric mean total protein was significantly higher in infected tamarins.

CONCLUSIONS

Sampled tamarins displayed typical signs of T. cruzi infection, similar to experimentally infected primates and human natural infection. Potential risk of T. cruzi infection to this endangered species is discussed.