Trypanosoma cruzi infection in neotropical wild carnivores (Mammalia: Carnivora): at the top of the T. cruzi transmission chain

Modeling the impact of non-human host predation on the transmission of Chagas disease

In addition to the traditional transmission route via the biting-and-defecating process, non-human host predation of triatomines is recognized as another significant avenue for Chagas disease transmission. In this paper, we develop an eco-epidemiological model to investigate the impact of predation on the disease's spread. Two critical thresholds, Rvp (the basic reproduction number of triatomines) and R0p (the basic reproduction number of the Chagas parasite), are derived to delineate the model's dynamics. Through the construction of appropriate Lyapunov functions and the application of the Bendixson-Dulac theorem, the global asymptotic stabilities of the equilibria are fully established. The vector-free equilibrium E0 is globally stable when Rvp<1. E1, the disease-free equilibrium, is globally stable when Rvp>1 and R0p<1, while the endemic equilibrium E∗ is globally stable when both Rvp>1 and R0p>1. Numerical simulations highlight that the degree of host predation on triatomines, influenced by non-human hosts activities, can variably increase or decrease the Chagas disease transmission risk. Specifically, low or high levels of host predation can reduce R0p to below unity, while intermediate levels may increase the infected host populations, albeit with a reduction in R0p. These findings highlight the role played by non-human hosts and offer crucial insights for the prevention and control of Chagas disease.

Phylogeographic analyses of an endemic Neotropical fox (Lycalopex vetulus) reveal evidence of hybridization with a different canid species (L. gymnocercus)

The hoary fox (Lycalopex vetulus) is the only species of the Canidae (Mammalia: Carnivora) endemic to Brazil, and so far has been the target of few genetic studies. Using microsatellites and mtDNA markers, we investigated its present genetic diversity and population structure. We also tested the hypothesis that this species currently hybridizes with the pampas fox (L. gymnocercus), as suggested by previous mtDNA data from two individuals. We collected tissue and blood samples from animals representing most of the two species' distributions in Brazil (n = 87), including their recently discovered geographic contact zone in São Paulo state. We observed that the hoary fox exhibits high levels of genetic diversity and low levels of population structure. We identified six individuals from São Paulo state with clear evidence of hybridization based on introgressed pampas fox mitochondrial DNA and/or admixed microsatellite genotypes (three individuals bore both types of evidence). These results demonstrate the existence of admixed individuals between hoary and pampas foxes in southeastern Brazil, representing the first identified case of interspecies admixture between native South American canids. We discuss our findings in the context of the evolutionary history of these foxes and address potential conservation implications of this interspecies hybridization process.

Merging socioecological variables to predict risk of Chagas disease

How far are we from predicting the occurrence of zoonotic diseases? In this paper we have made use of both socioecological and ecological variables to predict Chagas disease occurrence. Chagas disease involves, Trypanosoma cruzi, a complex life-cycle parasite which requires two hosts: blood-feeding triatomine insects and vertebrate hosts including humans. We have used a common risk assessment method combined with datasets that imply critical environmental and socioeconomic drivers of Chagas dynamics to predict the occurrence of this disease. We also carried out a network analysis to assess the interactions among triatomines and mammal host species given their human contact via whether hunted, domesticated or associated with anthropogenic landscapes in Mexico. We found that social backwardness variation, lack of health services and altitude had the largest relative influence Chagas events. Triatoma pallidipennis made use of the largest host diversity. Host species shared by the highest number of different triatomines were a woodrat, the highly appreciated bushmeat, and racoon. These results indicate both the predominance of socio-economic factors over ecological ones, and how close we are from predicting zoonotic diseases.

Detection and Genotyping of Trypanosoma cruzi Samples in Species of Genus Rhodnius from Different Environments in the Brazilian Amazon

Background: In the Amazon region, several species of triatomines occur in the natural environments. Among them, species of the genus Rhodnius are a risk to human populations due to their high rates of infection with Trypanosoma cruzi. The aim of this study was to identify the T. cruzi genotypes in Rhodnius specimens and their relationship with sylvatic hosts from different environments in the Brazilian Amazon. Methods: A total of 492 triatomines were collected from the municipalities of Monte Negro, Rondônia state, and Humaitá, Amazonas state, 382 of them being nymphs and 110 adults. Genotyping of T. cruzi in six discrete typing units (DTUs) was performed using conventional multilocus PCR. The triatomines that were positive for T. cruzi and engorged with blood were also targeted for amplification of the cytochrome B (cytB) gene to identify bloodmeal sources. Results: Of the 162 positive samples, the identified DTUs were TcI (87.65%) and TcIV (12.35%). It was observed that 102 specimens were engorged with a variety of bloodmeals. Triatomines infected with TcI were associated with DNA of all identified vertebrates, except Plecturocebus brunneus. TcIV was detected in triatomines that fed on Coendou prehensilis, Didelphis marsupialis, Mabuya nigropunctata, P. brunneus, Pithecia irrorata, Sapajus apella, and Tamandua tetradactyla. Conclusion: Results highlight the need to understand the patterns of T. cruzi genotypes in Rhodnius spp. and their association with sylvatic hosts to better elucidate their role in the transmission of Chagas disease in the Amazon region.

Oral Chagas Disease in Colombia-Confirmed and Suspected Routes of Transmission

Chagas disease (CD) remains endemic throughout many regions of Colombia despite implementing decades of vector control strategies in several departments. Some regions have had a significant decrease in vectorial transmission, but the oral ingestion of Trypanosoma cruzi through consumption of contaminated food and drink products is increasingly described. This form of transmission has important public health relevance in Colombia due to an increase in reported acute CD cases and clinical manifestations that often lead to significant morbidity and mortality. Oral CD in Colombia has been associated with the consumption of contaminated fruit juices, such as palm wine, sugar cane, or tangerine juice and water for consumption, or contaminated surfaces where food has been prepared. Another interesting route of oral transmission includes ingestion of unbeknownst infected armadillos' blood, which is related to a traditional medicine practice in Colombia. Some earlier reports have also implemented consumption of infected bush meat as a source, but this is still being debated. Within the Amazon Basin, oral transmission is now considered the principal cause of acute CD in these regions. Furthermore, new cases of acute CD are now being seen in departments where CD has not been documented, and triatomine vectors are not naturally found, thus raising suspicion for oral transmission. The oral CD could also be considered a food-borne zoonosis, and odoriferous didelphid secretions have been implemented in contaminating the human dwelling environment, increasing the risk of consumption of infectious metacyclic trypomastigotes. In this article, we will discuss the complex transmission dynamics of oral CD in Colombia and further examine the unique clinical manifestations of this route of infection. New insights into the oral transmission of Trypanosoma cruzi are being discovered in Colombia, which can help bring increased awareness and a better understanding of this neglected tropical disease to reduce the burden of CD throughout Latin America.

TRYPANOSOMA CRUZI INFECTION IN THREE SLENDER-TAILED MEERKATS (SURICATA SURICATTA)

Trypanosoma cruzi is a protozoan parasite primarily transmitted by triatomine insects (Hemiptera: subfamily Reduviidae) and is the cause of Chagas disease (CD). This report describes three cases of CD in a mob of five slender-tailed meerkats (Suricata suricatta) living in an outdoor exhibit at one zoological institution in Texas. The index case was a 9.5-yr-old female that presented with ataxia, lethargy, and pleural effusion. This case was diagnosed with CD postmortem via cytology, T. cruzi PCR of whole blood and lung fluid, and histology. Blood was opportunistically collected from the remaining four meerkats 28 d after the death of the index case and tested by PCR and serology. The second case was a clinically normal 7.5-yr-old male that tested PCR and antibody positive and the third case was a clinically normal 9-yr-old female that tested PCR positive. The second animal presented depressed, with pneumonia, and with continuous shivering 53 d after blood collection, and clinically improved after treatment with antibiotics and supportive care. Fifteen days later, the animal was found minimally responsive and died shortly thereafter. Histologic examination revealed Trypanosoma sp. amastigotes in the myocardium and the tissue was positive for T. cruzi DNA. The third meerkat, which received two separate courses of benznidazole over a span of almost 2 yr, was monitored routinely by PCR and serology and appeared clinically normal until found dead on exhibit 93 d after completion of the second treatment. Myocardium was positive for T. cruzi DNA. To the authors' knowledge, this case series is the first to document Chagas disease in meerkats and features associated cytologic and histologic findings.

"Mi Casa, Tu Casa": the coati nest as a hub of Trypanosoma cruzi transmission in the southern Pantanal biome revealed by molecular blood meal source identification in triatomines

BACKGROUND

The study of the ecology of Trypanosoma cruzi is challenging due to its extreme adaptive plasticity, resulting in the parasitism of hundreds of mammal species and dozens of triatomine species. The genetic analysis of blood meal sources (BMS) from the triatomine vector is an accurate and practical approach for gathering information on which wild mammal species participate in a local transmission network. South American coatis, Nasua nasua, act as important reservoir host species of T. cruzi in the Pantanal biome because of their high rate of infection and elevated parasitemia, with the main discrete typing unit (DTU) lineages (TcI and TcII). Moreover, the carnivore coati is the only mammal species to build high arboreal nests for breeding and resting that can be shared by various vertebrate and invertebrate species. Herein, we applied the sensitive and specific methodology of DNA barcoding and molecular cloning to study triatomines found in a coati nest to access the diversity of mammal species that explore this structure, and therefore, may be involved in the parasite transmission network.

METHODS

Twenty-three Triatoma sordida were collected in one coati's nest in the subregion of Nhecolândia, Pantanal. The DNA isolated from the gut of insects was subjected to BMS detection by PCR using universal primers that flank variable regions of the cytochrome b (cytb) and 12S rDNA mitochondrial genes from vertebrates. The Trypanosoma spp. diagnosis and DTU genotyping were based on an 18S rDNA molecular marker and also using new cytb gene primers designed in this study. Phylogenetic analyses and chord diagrams were constructed to visualize BMS haplotypes, DTU lineages detected on vectors, and their interconnections.

RESULTS

Twenty of 23 triatomines analyzed were PCR-positive (86.95%) showing lineages T. cruzi DTU TcI (n = 2), TcII (n = 6), and a predominance of TcI/TcII (n = 12) mixed infection. Intra-DTU diversity was observed mainly from different TcI haplotypes. Genetic analyses revealed that the southern anteater, Tamandua tetradactyla, was the unique species detected as the BMS of triatomines collected from the coati's nest. At least three different individuals of T. tetradactyla served as BMS of 21/23 bugs studied, as indicated by the cytb and 12S rDNA haplotypes identified.

CONCLUSIONS

The identification of multiple BMS, and importantly, different individuals of the same species, was achieved by the methodology applied. The study demonstrated that the southern anteaters can occupy the South American coati's nest, serving as the BMS of T. sordida specimens. Since anteaters have an individualist nonsocial behavior, the three individuals detected as BMS stayed at the coati's nest at different times, which added a temporal character to BMS detection. The TcI and TcII infection, and significantly, a predominance of TcI/TcII mixed infection profile with different TcI and TcII haplotypes was observed, due to the discriminatory capacity of the methodology applied. Tamandua tetradactyla, a host which has been little studied, may have an important role in the T. cruzi transmission in that Pantanal subregion. The data from the present study indicate the sharing of coatis' nests by other mammal species, expanding the possibilities for T. cruzi transmission in the canopy strata. We propose that coatis' nests can act as the true hubs of the T. cruzi transmission web in Pantanal, instead of the coatis themselves, as previously suggested.

Discrete typing units of Trypanosoma cruzi: Geographical and biological distribution in the Americas

Chagas disease caused by Trypanosoma cruzi is a public health issue in Latin America. This highly diverse parasite is divided into at least seven discrete typing units (DTUs) TcI-TcVI and Tcbat. Some DTUs have been associated with geographical distribution in epidemiological scenarios and clinical manifestations, but these aspects remain poorly understood. Many studies have focused on studying the parasite and its vectors/hosts, using a wide variety of genetic markers and methods. Here, we performed a systematic review of the literature for the last 20 years to present an update of DTUs distribution in the Americas, collecting ecoepidemiological information. We found that the DTUs are widespread across the continent and that there is a whole gamma of genetic markers used for the identification and genotyping of the parasite. The data obtained in this descriptor could improve the molecular epidemiology studies of Chagas disease in endemic regions.

Measurement(s)	Genotype
Technology Type(s)	Report from Literature

Trypanosomatid Richness in Wild and Synanthropic Small Mammals from a Biological Station in Rio de Janeiro, Brazil

Trypanosomatids are diverse and can infect several host species, including small mammals (rodents and marsupials). Between 2012 and 2014, 91 small mammals were surveyed for trypanosomatid infection in the Estação Biológica FIOCRUZ Mata Atlântica (EFMA), an Atlantic Forest area in Rio de Janeiro that presents different levels of conserved and degraded areas. Blood, skin, liver, and spleen samples were submitted to parasitological, serological, and molecular assays to detect the infection and determine the taxonomic status of their parasites. Sixty-eight individuals (74.7%; n = 91) were infected by trypanosomatids, including fourteen mixed infected by different trypanosomatid parasites. These hosts were infected by: T. cruzi DTU TcI (n = 12), T. cruzi DTU TcIV (n = 2), T. janseni (n = 15), T. dionisii (n = 1), and T. rangeli A (n = 1) detected in blood or tissue cultures, in addition to T. cruzi DTU TcI (n = 9) and Leishmania sp. (n = 1) only by the molecular diagnosis. Serological diagnosis was positive in 38 (71.6%) individuals for T. cruzi, the same amount for Leishmania spp., and 23 (43.3%) individuals were mixed infected. These data indicate a remarkable richness of trypanosomatid species/genotypes infecting small mammals, even in a disturbed area with low mammal species diversity—as is the case of the EFMA—reinforcing the generalist aspect of these parasites.

Serosurvey of antibodies against zoonotic pathogens in free-ranging wild canids (Cerdocyon thous and Lycalopex gymnocercus) from Southern Brazil

The expansion of urbanization on natural areas is increasing contact between human populations with wild animals. Wild carnivores can act as sentinel hosts or environmental health indicators. Thus, the aim of this work was to investigate the exposure of two major species of wild canids from Southern Brazil to selected pathogens. For that, we live-trapped free-ranging Cerdocyon thous and Lycalopex gymnocercus in five localities and determined the frequency of animals with antibodies against Toxoplasma gondii, Trypanosoma cruzi, Leishmania infantum, Neospora caninum, and Leptospira spp. Among the canids sampled, 23% (12/52) (95%CI: 13-36%) had antibodies against T. gondii, with titers ranging from 64 to 512. For T. cruzi, 28% (15/52) (95%CI: 18-42%) of sampled canids were seropositive, with titers ranging from 8 to 64. Concerning the protozoan pathogen N. caninum, a total of 5% (3/52) (95%CI: 2-15%) of wild canids had antibodies against it. None of the sampled canids showed the presence of antibodies against L. infantum. On the other hand, 44% (23/52) (95%CI: 31-57%) of the wild canids showed antibodies against Leptospira spp. The set of results presented here, show that free-ranging neotropical wild canids are exposed and have antibodies against to T. gondii, T. cruzi, Leptospira spp., and to a lesser degree to N. caninum. We found no evidence of L. infantum circulation among the studied populations. These results highlight some of the major pathogens which may represent risks for populations of these wild canids. DATA AVAILABILITY STATEMENT: The data that support the findings of this study are available from the corresponding author upon reasonable request.

Trypanosoma cruzi and Incidental Sarcocystis spp. in Endangered Ocelots (Leopardus pardalis) of South Texas, USA

The federally endangered ocelot (Leopardus pardalis) population of south Texas, USA is declining; fewer than an estimated 80 ocelots remain. South Texas has robust transmission of Trypanosoma cruzi, the protozoan parasite causing Chagas disease in humans and various mammals. This parasite's impact in ocelots is unknown. Blood from live-trapped ocelots was collected by US Fish and Wildlife Service personnel in an annual monitoring program; additionally, tissues were obtained from carcasses collected from 2010 to 2017 around Laguna Atascosa National Wildlife Refuge in south Texas and placed in scientific collections. Variable samples were available from 21 ocelots: skeletal muscle (n=15), heart tissue (n=5), lung (n=1), kidney (n=1), spleen (n=1), liver (n=1), blood clot (n=9), and serum (n=3). Overall, 3/21 (14.3%) ocelots showed evidence of T. cruzi infection or exposure, with T. cruzi PCR-positive samples of skeletal muscle, heart, and blood clot, respectively. All three were infected with the T. cruzi discrete taxonomic unit "TcI"; one of these ocelots also had anti-T. cruzi antibodies. Lymphoplasmacytic inflammation was noted in the PCR-positive heart tissue and in some PCR-negative tissues from this and other individuals. Incidentally, Sarcocystis spp. were noted histologically in five ocelots. Trypanosoma cruzi infection and associated cardiac lesions suggest that this parasite should be further investigated in vulnerable populations.

Intestinal Parasites of Neotropical Wild Jaguars, Pumas, Ocelots, and Jaguarundis in Colombia: Old Friends Brought Back from Oblivion and New Insights

Neotropical wild felids (NWF) are obligate carnivore species present in Central and South America, and some are considered endangered due to constantly decreasing populations. NWF can become infected by a wide range of protozoan and metazoan parasites, some of them affecting their health conditions and others having anthropozoonotic relevance. Parasitological studies on NWF are still very scarce, and most data originated from dead or captive animals. On this account, the current study aimed to characterize gastrointestinal parasites of free-ranging jaguars (Panthera onca), pumas (Puma concolor), ocelots (Leopardus pardalis), and jaguarundis (Herpailurus yagouaroundi), i.e., four out of six NWF species endemic to Colombia. Fecal samples from jaguars (n = 10) and ocelots (n = 4) were collected between 2012 and 2017 as part of the Jaguar Corridor Initiative from six geographic locations in Colombia. In addition, cestode specimens were obtained during puma and jaguarundi necropsies. Scat samples were processed by standardized sodium acetate-acetic acid-formalin (SAF), sedimentation, and flotation techniques and by carbol fuchsin-stained fecal smears. Morphological evaluation of feces showed the presence of one cestode (Spirometra sp.), a nematode (Toxocara cati), an acanthocephalan (Oncicola sp.), and one cyst-forming coccidian (Cystoisospora-like oocysts). Feces oocysts were submitted to a Toxoplasma gondii-specific PCR for species identification, but no product was amplified. The cestodes isolated from a puma and jaguarundi were molecularly characterized by sequencing cytochrome c oxidase subunit I, identifying them as Taenia omissa and as a T. omissa sister lineage, respectively. These results collectively demonstrate the potential role of NWF as natural reservoir hosts for neglected zoonotic parasites (e.g., Spirometra sp., T. cati) and highlight their possible role in parasite transmission to human communities. Due to public health concerns, the occurrence of these parasites should be monitored in the future for appropriate zoonotic management practices in conservation strategies and wild felid health management programs.

Natural infection with Trypanosoma cruzi in three species of non-human primates in southeastern Mexico: A contribution to reservoir knowledge

The mechanisms of infection and dispersion of Trypanosoma cruzi among animals, especially in the sylvatic environment, are still not entirely clear, and various aspects of the transmission dynamics of this parasite in the sylvatic environment are still unknown. T. cruzi is a parasite with a great biological and genetic diversity that infects a wide variety of hosts, therefore, transmission cycles of this parasite are complex. The objective of this study was to determine the prevalence of T. cruzi infection and analyze the genetic variability of the discrete typing units (DTUs) of the parasite in three non-human primate species (Alouatta palliata, Alouatta pigra, and Ateles geoffroyi) in southeastern Mexico. A total of one hundred sixty-four serum samples (42 samples of A. pigra, 41 samples of A. palliata (free-ranging) and 81 samples of A. geoffroyi (hosted in care centers)) were analyzed for the detection of anti-T. cruzi antibodies by ELISA assays. The seroprevalence of infection was 23.39% in A. palliata, 21.40% in A. pigra and 16.27% in A. geoffroyi. Additionally, presence of parasite DNA was assessed by PCR, and the identification of DTUs was performed by real-time PCR coupled to High Resolution Melting (qPCR-HRM). Different DTUs (TcI, TcII, TcIII, TcV and TcVI) were found in the analyzed monkeys. In addition, infection of monkeys was not associated with age or gender, but it was associated with the species. This study reveals the risk of infection in the study area and that the different DTUs of the parasite can coexist in the same habitat, indicating that T. cruzi transmission in the study area is very complex and involves many ecological factors. However, there is a need for long-term studies of host-parasite interactions to provide a solid understanding of the ecology of these species and to understand the dispersion strategies of T. cruzi.

Survey of ticks and tick-borne agents in maned wolves (Chrysocyon brachyurus) from a natural landscape in Brazil

This study evaluated ticks and tick-borne agents in 104 captures of the maned wolf Chrysocyon brachyurus (50 different individuals and 54 recaptures) in the Serra da Canastra National Park (SCNP), a Cerrado preserved area in southeastern Brazil, from 2005 to 2012. From the 104 capture events, a total of 1,206 ticks were collected on 94 occasions (90.4 %), and identified into five species: Amblyomma tigrinum (77.3 % of all collected ticks), Amblyomma sculptum (16.6 %), Amblyomma ovale (0.1 %), Amblyomma brasiliense (0.1 %), Rhipicephalus microplus (0.1 %), and Amblyomma spp. larvae (5.8 %). Molecular analyses of A. tigrinum adult ticks revealed the presence of 'Candidatus Rickettsia andeanae', Rickettsia parkeri sensu stricto, two different haplotypes of 'Ca. Midichloria sp.', and a Hepatozoon canis haplotype. Molecular analyses of maned wolf blood samples revealed two distinct haplotypes of Hepatozoon spp., one identical to the H. canis genotype that was detected in the A. tigrinum ticks, and a Hepatozoon americanum-like haplotype. None tick or blood samples yielded amplicons through PCR assays targeting the genera Ehrlichia, Anaplasma, Babesia, Rangelia, Cytauxzoon, and Theileria. Maned wolf serum samples were tested by immunofluorescence assay against antigens of five Rickettsia species (R. parkeri, R. rickettsii, R. amblyommatis, R. rhipicephali, and R. bellii) and Ehrlichia canis. Among 78 serum samples (45 captures plus 33 recaptures), 74 (95 %) were reactive to at least one Rickettsia species, with R. parkeri eliciting the highest endpoint titers. Some maned wolves that were recaptured during the study were shown to seroconvert to R. parkeri. Serum-reactiveness to E. canis was detected in 36 % (16/45) maned wolves. During the study, general clinical signs of tick-borne diseases were not found in any of the captured animals, indicating that they were under a good health status in the SCNP, despite of been exposed to ticks (mostly A. tigrinum) and some tick-borne agents (Rickettsia, Hepatozoon, Ehrlichia). The results of the present study might represent baseline data for the conservation of the maned wolf in its natural habitat, which should be used to interpret further studies about ticks and tick-borne diseases in maned wolves within human-modified landscapes.

Blood Parasites in Endangered Wildlife-Trypanosomes Discovered During a Survey of Haemoprotozoa from the Tasmanian Devil

The impact of emerging infectious diseases is increasingly recognised as a major threat to wildlife. Wild populations of the endangered Tasmanian devil, Sarcophilus harrisii, are experiencing devastating losses from a novel transmissible cancer, devil facial tumour disease (DFTD); however, despite the rapid decline of this species, there is currently no information on the presence of haemoprotozoan parasites. In the present study, 95 Tasmanian devil blood samples were collected from four populations in Tasmania, Australia, which underwent molecular screening to detect four major groups of haemoprotozoa: (i) trypanosomes, (ii) piroplasms, (iii) Hepatozoon, and (iv) haemosporidia. Sequence results revealed Trypanosoma infections in 32/95 individuals. Trypanosoma copemani was identified in 10 Tasmanian devils from three sites and a second Trypanosoma sp. was identified in 22 individuals that were grouped within the poorly described T. cyclops clade. A single blood sample was positive for Babesia sp., which most closely matched Babesia lohae. No other blood protozoan parasite DNA was detected. This study provides the first insight into haemoprotozoa from the Tasmanian devil and the first identification of Trypanosoma and Babesia in this carnivorous marsupial.

Wild and Domestic Canids and Their Interactions in the Transmission Cycles of Trypanosoma Cruzi and Leishmania spp. in an Area of the Brazilian Cerrado

Trypanosoma cruzi and Leishmania spp. are parasites that infect multiple hosts including canids, considered bioaccumulators of parasites. Deforestation in the Cerrado biome has resulted in the exposure of wild canids to anthropized areas, where they may establish ecological and epidemiological relationships with domestic dogs. We evaluated the infection by trypanosomatids in canids from a Cerrado agroecosystem between 2013 and 2017. Samples of wild canids (blood, bone marrow and skin) and dogs (blood) were collected for parasitological, serological and molecular diagnosis. A total of 414 samples from wild (n = 131) and domestic (n = 283) canids were collected, including recaptures. We obtained five positive hemocultures from Lycalopex vetulus (n = 2), Cerdocyon thous (n = 1) and dogs (n = 2), all characterized as T. cruzi TcIII/V (18S rDNA) and TcIII/V/VI (gGAPDH); one positive skin fragment for Leishmania sp. (C. thous), one positive skin culture (Chrysocyon brachyurus) and one positive fresh blood examination from a dog. Infection by T. cruzi and Leishmania spp. was serologically confirmed in 18% and 4% of the canids, respectively. Active transmission was attested by seroconversion events and occurred despite the low rate of positive parasitological assays. Wild and domestic canids infected by both parasites were detected sharing the same areas, pointing to a possible spillover of parasites among them.

Combination of acamprosate and baclofen (PXT864) as a potential new therapy for amyotrophic lateral sclerosis

There is currently no therapy impacting the course of amyotrophic lateral sclerosis (ALS). The only approved treatments are riluzole and edaravone, but their efficacy is modest and short‐lasting, highlighting the need for innovative therapies. We previously demonstrated the ability of PXT864, a combination of low doses of acamprosate and baclofen, to synergistically restore cellular and behavioral activity in Alzheimer's and Parkinson's disease models. The overlapping genetic, molecular, and cellular characteristics of these neurodegenerative diseases supported investigating the effectiveness of PXT864 in ALS. As neuromuscular junction (NMJ) alterations is a key feature of ALS, the effects of PXT864 in primary neuron‐muscle cocultures injured by glutamate were studied. PXT864 significantly and synergistically preserved NMJ and motoneuron integrity following glutamate excitotoxicity. PXT864 added to riluzole significantly improved such protection. PXT864 activity was then assessed in primary cultures of motoneurons derived from SOD1^G93A rat embryos. These motoneurons presented severe maturation defects that were significantly improved by PXT864. In this model, glutamate application induced an accumulation of TDP‐43 protein in the cytoplasm, a hallmark that was completely prevented by PXT864. The anti‐TDP‐43 aggregation effect was also confirmed in a cell line expressing TDP‐43 fused to GFP. These results demonstrate the value of PXT864 as a promising therapeutic strategy for the treatment of ALS.

Prevalence and Epitope Recognition of Anti-Trypanosoma cruzi Antibodies in Two Procyonid Species: Implications for Host Resistance

More than 180 mammalian species have been found naturally infected with Trypanosoma cruzi. Many of them play an important role in the maintenance of this parasite. In particular, new studies have appeared which indicate that some species of Procyonidae family may play a role as T. cruzi hosts, however, more data are needed to evaluate their long-term physiological response to parasite infection, especially for specific antibodies. In this study, antibodies to T. cruzi were detected and prevalence and epitope recognition were assessed by ELISA (using discrete typing unit (DTU) I as antigen) and WB (using DTU I and DTU II as antigens) and sera from two procyonid species obtained through five-year follow-up of two semicaptive populations living in the same habitat. Marked heterogeneity in antigens recognition between species and differences in seroprevalence (p = 0.0002) between white-nosed coatis (Nasua narica), 51.8% (115/222), and common raccoons (Procyon lotor), 28.3% (23/81), were found. Antigens with high molecular weight when DTU-I was used were the most recognized, while a greater antigen diversity recognition was observed with DTU-II; for white-nosed coatis, low-molecular-weight antigens were mainly recognized, while for common raccoons proteins with molecular weights greater than 80 kDa were recognized most. These divergent humoral immune responses could be related to an alleged pattern of recognition receptors and major histocompatibility complex molecules difference in the procyonids species.

Trypanosomatid infections in captive wild mammals and potential vectors at the Brasilia Zoo, Federal District, Brazil

Background

Conservation projects in zoos may involve translocation of captive animals, which may lead to pathogen spread. Neotropical mammals are important hosts of Trypanosoma cruzi and Leishmania spp. the etiological agents of Chagas disease and Leishmaniasis respectively. Studies of trypanosomatid‐infected mammals and vectors (triatomines and sandflies) in zoos are important for the establishment of surveillance and control measures.

Objectives

We investigated trypanosomatid infections in captive wild mammals, triatomines and sandflies at the Brasília Zoo.

Methods

We collected triatomines during active bimonthly surveys, sampled sandflies using light‐traps and obtained blood samples from 74 mammals between 2016 and 2017. We used quantitative PCR to detect trypanosomatids in vectors and mammals.

Results

We found a colony of 19 Panstrongylus megistus in the porcupine unit and detected T. cruzi infections in five bugs. We captured 17 sandflies of four species including Nyssomyia whitmani and Lutzomyia longipalpis, but no Leishmania infection was detected. qPCR detected 50 T. cruzi‐infected mammals belonging to 24 species and five groups of mammals (Carnivora, Cetartiodactyla, Perissodactyla, Pilosa and Primates); Leishmania DNA was detected in 23 mammals from 15 species, mainly carnivores. We detected trypanosomatid infections in 11 mammals born at the Brasília Zoo.

Conclusions

Our results suggest vector‐borne transmission of T. cruzi among maned wolves; measures to reduce the risk of new infections should therefore be taken. We also report sandfly presence and Leishmania‐infected mammals at the Brasília Zoo. Translocation of wild mammals in and out of the Brasília Zoo should consider the risk of T. cruzi and Leishmania spread.

The reservoir system for Trypanosoma (Kinetoplastida, Trypanosomatidae) species in large neotropical wetland

Distinct species of Trypanosoma have been documented sharing the same hosts in different environments in intricate transmission networks. Knowing this, this study investigated the role of different hosts in the transmission cycles of Trypanosoma species in the Pantanal biome. The mammals were sampled from November 2015 to October 2016. We sampled a total of 272 wild mammals from 27 species belonging to six orders and 15 families, and three species of triatomines (n = 7). We found high parasitemias by Hemoculture test for Trypanosoma cruzi (TcI), Trypanosoma rangeli, Trypanosoma cruzi marinkellei and Trypanosoma dionisii, and high parasitemias by Microhematocrit Centrifuge Technique for Trypanosoma evansi. The carnivore Nasua nasua is a key host in the transmission cycles since it displayed high parasitemias for T. cruzi, T. evansi and T. rangeli. This is the first report of high parasitemias in Tamandua tetradactyla and cryptic infection in Dasypus novemcinctus by T. cruzi; cryptic infection by T. evansi in Eira barbara, Euphractus sexcinctus and Dasyprocta azarae. The collection of Panstrongylus geniculatus increased the geographic distribution of this vector species in the South America. Our results indicate that Trypanosoma species circulate in a complex reservoir system including different host species with different infective competences.

Trypanosomatids in Small Mammals of an Agroecosystem in Central Brazil: Another Piece in the Puzzle of Parasite Transmission in an Anthropogenic Landscape

We surveyed infection by Trypanosoma spp. and Leishmania spp. in small wild mammals from Cumari, Goiás State aiming to investigate the diversity of trypanosomatid in a modified landscape of the Brazilian Cerrado (and possible infection overlapping with canids from the same area). Blood, skin, spleen, and liver samples were collected for parasitological, serological, and molecular assays. Gracilinanus agilis was the most abundant species (N = 70; 48.6%) and it was the only one with patent parasitemia. Characterization by mini-exon and 18SrDNA targets were achieved in 7/10 hemocultures with positive fresh blood examination, which confirmed the T. cruzi infection by Discrete Typing Units (DTU) TcI in single (N = 2) and mixed infections with other DTUs (N = 5). T. rangeli and T. dionisii were detected in skin fragments from Didelphis albiventris and Oecomys cleberi, respectively. G. agilis were found to be infected by L. braziliensis and L. guyanensis, while Leishmania sp. DNA was detected in the liver of Oligoryzomys nigripes and Calomys expulsus. Subpatent infection by T. cruzi and Leishmania sp. was serologically detected in 15% and 9% of the small mammal fauna, respectively. Small mammals from Cumari are included in T. cruzi and Leshmania spp. transmission cycles, showing a higher diversity of trypanosomatid species and/or genotypes than that observed in canids of the same agroecosystem.

Heterogeneity of Trypanosoma cruzi infection rates in vectors and animal reservoirs in Colombia: a systematic review and meta-analysis

Background

The heterogeneity of Trypanosoma cruzi infection rates among triatomines insects and animal reservoirs has been studied in independent studies, but little information has been systematised to allow pooled and comparative estimates. Unravelling the main patterns of this heterogeneity could contribute to a further understanding of T. cruzi transmission in Colombia.

Methods

A systematic search was conducted in PubMed, Medline, LILACS, Embase, Web of Knowledge, Google Scholar and secondary sources with no filters of language or time and until April 2018. Based on selection criteria, all relevant studies reporting T. cruzi infection rates in reservoirs or triatomines were chosen. For pooled analyses, a random effects model for binomial distribution was used. Heterogeneity among studies is reported as I². Subgroup analyses included: taxonomic classification, ecotope and diagnostic methods. Publication bias and sensitivity analyses were performed.

Results

Overall, 39 studies reporting infection rates in Colombia were found (22 for potential reservoirs and 28 for triatomine insects) for a total sample of 22,838 potential animals and 11,307 triatomines evaluated for T. cruzi infection. We have found evidence of 38/71 different animal species as potential T. cruzi reservoirs and 14/18 species as triatomine vectors for T. cruzi. Among animals, the species with the highest pooled prevalence were opossum (Didelphis marsupialis) with 48.0% (95% CI: 26–71%; I² = 88%, τ² = 0.07, P < 0.01) and domestic dog (Canis lupus familiaris) with 22.0% (95% CI: 4–48%; I² = 96%, τ² = 0.01, P < 0.01). Among triatomines, the highest prevalence was found for Triatoma maculata in the peridomestic ecotope (68.0%, 95% CI: 62–74%; I² = 0%, τ² = 0, P < 0.0001), followed by Rhodnius prolixus (62.0%, 95% CI: 38–84%; I² = 95%, τ² = 0.05, P < 0.01) and Rhodnius pallescens (54.0%, 95% CI: 37–71%; I² = 86%, τ² = 0.035, P < 0.01) in the sylvatic ecotope.

Conclusions

To our knowledge, this is the first systematic and quantitative analyses of triatomine insects and potential animal reservoirs for T. cruzi infection in Colombia. The results highlight a marked heterogeneity between species and provide initial estimates of infection rates heterogeneity.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3541-5) contains supplementary material, which is available to authorized users.

Infection by Trypanosoma cruzi in the central nervous system in non-human mammals: a systematic review

Currently, the types and distribution of the lesions induced in the central nervous system (CNS) by Trypanosoma cruzi remain unclear as the available evidence is based on fragmented data. Therefore, we developed a systematic review to analyse the main characteristics of the CNS lesions in non-human hosts infected. From a structured search on the PubMed/Medline and Scopus platforms, 32 studies were retrieved, subjected to data extraction and methodological bias analysis. Our results show that the most frequent alterations in the CNS are the presence of different forms of T. cruzi and intense lymphocytes infiltrates. The encephalon is the main target of T. cruzi, and inflammatory changes in the CNS are more frequent and severe in the acute phase of infection. The parasite's genotype and phenotype are associated with the tropism and severity of the CNS lesions. The methodological limitations found in the studies were divergences in inoculation pathways, under-reporting of animal age and weight, sample calculation strategies and histopathological characterization. Since the changes were dependent on the pathogenicity and virulence of the T. cruzi strains, the genotype and phenotype characterization of the parasite are extremely relevant to predict changes in the CNS and the neurological manifestations associated with Chagas' disease.

Uncovering Trypanosoma spp. diversity of wild mammals by the use of DNA from blood clots

Trypanosoma spp. infection in wild mammals is detected mainly through parasitological tests that usually display low sensitivity. We propose the use of DNA extracted directly from blood clots (BC), which are neglected sources of DNA for diagnosis and identification of Trypanosoma spp. This approach followed by nested PCR targeting the 18S SSU rDNA demonstrated to be sensitive and suitable to evaluate the diversity of trypanosomes infecting sylvatic mammals, including subpatent and mixed infections. Infection was detected in 95/120 (79.2%) samples from bats, carnivores and marsupials that included negative serological and hemoculture testing mammals. Thirteen Trypanosoma spp. or Molecular Operational Taxonomic Units (MOTUs) were identified, including two new MOTUs. The high diversity of trypanosomes species and MOTUs infecting bats and marsupials showed that these hosts can be considered as bio-accumulators of Trypanosoma spp., with specimens of Didelphis spp. displaying the highest trypanosome diversity. The use of blood clots allowed direct access to non-culturable parasites, mixed infections, besides bypassing the selective pressure on the parasites inherent to cultivation procedures. Trypanosoma cruzi was the species found infecting the highest number of individuals, followed by T. lainsoni. Positive PCR for T. cruzi was observed in 16 seronegative individuals and 30 individuals with negative hemocultures. Also, T. lainsoni, previously found only in rodents, showed to be capable of infecting bats and marsupials. This finding makes it clear that some species of Trypanosoma are more generalist than previously thought. Molecular diagnosis using nested PCR from DNA extracted from BC allowed the increase of the knowledge about host-spectrum and distribution of Trypanosoma spp. and allowed the identification of new MOTUs.

Toward an Ecological Framework for Assessing Reservoirs of Vector-Borne Pathogens: Wildlife Reservoirs of Trypanosoma cruzi across the Southern United States

Wildlife species are critical for both feeding vectors and serving as reservoirs of zoonotic vector-borne pathogens. Transmission pathways leading to disease in humans or other target taxa might be better understood and managed given a complete understanding of the relative importance of different reservoir species in nature. Using the conceptual framework of “reservoir potential,” which considers elements of both reservoir competence and vector-host contact, we review the wildlife reservoirs of Trypanosoma cruzi in the southern United States, where many species of triatomine vectors occur and wildlife maintain enzootic cycles that create a risk of spillover to humans, domestic dogs, and captive nonhuman primates that may develop Chagas disease. We reviewed 77 published reports of T. cruzi infection in at least 26 wildlife species across 15 southern states. Among the most well-studied and highly infected reservoirs are raccoon (Procyon lotor), woodrat (Neotoma spp.), and opossum (Didelphis virginiana), with aggregate overall infection prevalences of 36.4, 34.7, and 22.9%, respectively. Just over 60% of studies utilized methods from which an infectiousness index could be generated and show that raccoons and striped skunk (Mephitis mephitis) are among the most infectious wildlife hosts. Triatomine-host contact has sparsely been quantified in the southern United States, but 18 of the 24 host species previously identified to have been fed upon by triatomines are wildlife. Future studies to parameterize the reservoir potential model, especially to quantify wildlife infectiousness, vector-host contact, and the epidemiological importance of parasite strains maintained by wildlife, could open new doors for managing enzootic cycles and reducing T. cruzi spillover risk.

Implementation science: Epidemiology and feeding profiles of the Chagas vector Triatoma dimidiata prior to Ecohealth intervention for three locations in Central America

The Ecohealth strategy is a multidisciplinary data-driven approach used to improve the quality of people's lives in Chagas disease endemic areas, such as regions of Central America. Chagas is a vector-borne disease caused by the parasite Trypanosoma cruzi. In Central America, the main vector is Triatoma dimidiata. Because successful implementation of the Ecohealth approach reduced home infestation in Jutiapa department, Guatemala, it was scaled-up to three localities, one in each of three Central American countries (Texistepeque, El Salvador; San Marcos de la Sierra, Honduras and Olopa, Guatemala). As a basis for the house improvement phase of the Ecohealth program, we determined if the localities differ in the role of sylvatic, synanthropic and domestic animals in the Chagas transmission cycle by measuring entomological indices, blood meal sources and parasite infection from vectors collected in and around houses. The Polymerase Chain Reaction (PCR) with taxa specific primers to detect both, blood sources and parasite infection, was used to assess 71 T. dimidiata from Texistepeque, 84 from San Marcos de la Sierra and 568 from Olopa. Our results show that infestation (12.98%) and colonization (8.95%) indices were highest in Olopa; whereas T. cruzi prevalence was higher in Texistepeque and San Marcos de la Sierra (>40%) than Olopa (8%). The blood meal source profiles showed that in Olopa, opossum might be important in linking the sylvatic and domestic Chagas transmission cycle, whereas in San Marcos de la Sierra dogs play a major role in maintaining domestic transmission. For Texistepeque, bird was the major blood meal source followed by human. When examining the different life stages, we found that in Olopa, the proportion bugs infected with T. cruzi is higher in adults than nymphs. These findings highlight the importance of location-based recommendations for decreasing human-vector contact in the control of Chagas disease.

Trypanosoma cruzi transmission in the wild and its most important reservoir hosts in Brazil

Trypanosoma cruzi (Kinetoplastea: Trypanosomatidae) infects all tissues of its hosts, which along with humans, include hundreds of mammalian species in the Americas. The epidemiology of T. cruzi has been changing in that currently the majority of the cases and/or outbreaks of Chagas disease occur by the ingestion of comestibles contaminated by T. cruzi metacyclic forms. These cases/outbreaks occur in distinct regional scenarios, mainly in the Amazon biome and are related to the local interaction mode of humans with their surroundings, as well as with the overall local ecological peculiarities. As trypanosomiasis caused by T. cruzi is primarily a zoonosis, understanding the variables that influences its transmission in the wild as well as the role played by the extant fauna in the maintenance of the parasite, is critical in establishing control measures. Here, we present the results of our studies of T. cruzi infection of free ranging wild mammalian fauna in the five biomes of Brazil, a country of continental dimensions. From 1992 up to 2017, we examined a total of 6587 free-ranging non-volant wild mammal specimens. Our studies found that 17% of mammals were seropositive and 8% of all animals displayed positive hemocultures indicative of high parasitemia and, consequently, of infectivity potential. We observed that opossums, mainly Philander spp. and Didelphis spp., the coati Nasua nasua, the capuchin monkey Sapajus libidinosus and the golden lion tamarin Leontopithecus rosalia, were mammal taxa that demonstrated higher rates of positive hemocultures. Additionally, Didelphis spp. demonstrated to be a competent bioaccumulator of TcI diversity. Chiroptera were distinguished for hosting the greatest diversity of species and genotypes of Trypanosoma spp. Additionally the observation of the higher host range of some Trypanosoma spp., shows the need to reassess the ecology of representatives of the taxon. Altogether, our results showed that each locality, may display distinct enzootiological and epidemiological scenarios that must be taken into account when it comes to establishing control and/or clarification campaigns of the local population.

Trypanosoma cruzi in Triatomines and wild mammals in the National Park of Serra das Confusões, Northeastern Brazil

INTRODUCTION

The National Park of Serra das Confusões (NPSC) is a protected area of natural landscape located in Southern Piauí, Brazil, and it is considered as one of the largest and most important protected areas in the Caatinga biome.

METHODS

The natural occurrences of trypanosomatids from hemocultures on small mammals and cultures from intestinal contents triatomines were detected through molecular diagnoses of blood samples, and phylogenetic relationship analysis of the isolates parasites using the trypanosome barcode (V7V8 SSUrDNA) were realized.

RESULTS

Only two Galea spixii (8.1%) and six Triatoma brasiliensis (17.6%) were positive by hemoculture, and the isolates parasites were cryopreserved. All the isolates obtained were positioned on the Trypanosoma cruzi DTU TcI branch.

CONCLUSIONS

Research focused on studying the wild animal fauna in preserved and underexplored environments has made it possible to elucidate indispensable components of different epidemiological chains of diseases with zoonotic potential.

Outcomes of Trypanosoma cruzi and Trypanosoma evansi infections on health of Southern coati (Nasua nasua), crab-eating fox (Cerdocyon thous), and ocelot (Leopardus pardalis) in the Brazilian Pantanal

The occurrence of Trypanosoma spp. in wild carnivore populations has been intensively investigated during the last decades. However, the impact of these parasites on the health of free-living infected animals has been largely neglected. The Pantanal biome is the world’s largest seasonal wetland, harboring a great diversity of species and habitats. This includes 174 species of mammals, of which 20 belong to the order Carnivora. The present study aimed to investigate the effect of Trypanosoma evansi and Trypanosoma cruzi infections and coinfections on the health of the most abundant carnivores in the Pantanal: coati (Nasua nasua), crab-eating fox (Cerdocyon thous), and ocelot (Leopardus pardalis). We captured 39 coatis, 48 crab-eating foxes, and 19 ocelots. Diagnostic tests showed T. cruzi infection in 7 crab-eating foxes and 5 coatis. Additionally, 7 crab-eating foxes, 10 coatis, and 12 ocelots were positive for T. evansi. We observed coinfections in 9 crab-eating foxes, 8 coatis, and 2 ocelots. This is the first report of T. evansi and T. cruzi infection on the health of free-living ocelots and crab-eating foxes. We showed that single T. evansi or T. cruzi infection, as well as coinfection, caused some degree of anemia in all animals, as well as an indirect negative effect on body condition in coatis and crab-eating foxes via anemia indicators and immune investment, respectively. Furthermore, the vigorous immune investment observed in sampled coatis, crab-eating foxes and ocelots infected by T. evansi, T. cruzi and coinfected can be highly harmful to their health. Overall, our results indicate that single and combined infection with T. evansi and T. cruzi represent a severe risk to the health of wild carnivores in the Pantanal region.

Imaging the development of chronic Chagas disease after oral transmission

Chagas disease is a zoonosis caused by the protozoan parasite Trypanosoma cruzi. Transmission cycles are maintained by haematophagous triatomine bug vectors that carry infective T. cruzi in their faeces. Most human infections are acquired by contamination of mucosal membranes with triatomine faeces after being bitten, however, T. cruzi can be transmitted by several other routes. Oral transmission is an increasingly important aspect of Chagas disease epidemiology, typically involving food or drink products contaminated with triatomines. This has recently caused numerous outbreaks and been linked to unusually severe acute infections. The long-term impact of oral transmission on infection dynamics and disease pathogenesis is unclear. We used highly sensitive bioluminescence imaging and quantitative histopathology to study orally transmitted T. cruzi infections in mice. Both metacyclic and bloodform trypomastigotes were infectious via the oral cavity, but only metacyclics led to established infections by intra-gastric gavage. Mice displayed only mild acute symptoms but later developed significantly increased myocardial collagen content (p = 0.017), indicative of fibrosis. Gastrointestinal tissues and skin were the principal chronic infection reservoirs. Chronic phase parasite load profiles, tissue distribution and myocardial fibrosis severity were comparable to needle-injected controls. Thus, the oral route neither exacerbates nor ameliorates experimental Chagas disease.

Trypanosoma cruzi Transmission Among Captive Nonhuman Primates, Wildlife, and Vectors

Natural infection of captive nonhuman primates (NHPs) with Trypanosoma cruzi (agent of Chagas disease) is an increasingly recognized problem in facilities across the southern USA, with negative consequences for NHP health and biomedical research. We explored a central Texas NHP facility as a nidus of transmission by characterizing parasite discrete typing units (DTU) in seropositive rhesus macaques (Macaca mulatta), identifying the wildlife reservoirs, and characterizing vector infection. In seropositive NHPs, we documented low and intermittent concentrations of circulating T. cruzi DNA, with two DTUs in equal proportions, TcI and TcIV. In contrast, consistently high concentrations of T. cruzi DNA were found in wild mesomammals at the facility, yet rodents were PCR-negative. Strong wildlife host associations were found in which raccoons (Procyon lotor) harbored TcIV and opossums (Didelphis virginiana) harbored TcI, while skunks (Mephitis mephitis) were infected with both DTUs. Active and passive vector surveillance yielded three species of triatomines from the facility and in proximity to the NHP enclosures, with 17% T. cruzi infection prevalence. Interventions to protect NHP and human health must focus on interrupting spillover from the robust sylvatic transmission in the surrounding environment.

Ecological multiplex interactions determine the role of species for parasite spread amplification

Despite their potential interplay, multiple routes of many disease transmissions are often investigated separately. As a unifying framework for understanding parasite spread through interdependent transmission paths, we present the 'ecomultiplex' model, where the multiple transmission paths among a diverse community of interacting hosts are represented as a spatially explicit multiplex network. We adopt this framework for designing and testing potential control strategies for Trypanosoma cruzi spread in two empirical host communities. We show that the ecomultiplex model is an efficient and low data-demanding method to identify which species enhances parasite spread and should thus be a target for control strategies. We also find that the interplay between predator-prey and host-parasite interactions leads to a phenomenon of parasite amplification, in which top predators facilitate T. cruzi spread, offering a mechanistic interpretation of previous empirical findings. Our approach can provide novel insights in understanding and controlling parasite spreading in real-world complex systems.

Molecular Epidemiology of Trypanosomatids and Trypanosoma cruzi in Primates from Peru

We determined the prevalence rate and risk of infection of Trypanosoma cruzi and other trypanosomatids in Peruvian non-human primates (NHPs) in the wild (n = 126) and in different captive conditions (n = 183). Blood samples were collected on filter paper, FTA cards, or EDTA tubes and tested using a nested PCR protocol targeting the 24Sα rRNA gene. Main risk factors associated with trypanosomatid and T. cruzi infection were genus and the human-animal context (wild vs captive animals). Wild NHPs had higher prevalence of both trypanosomatids (64.3 vs 27.9%, P < 0.001) and T. cruzi (8.7 vs 3.3%, P = 0.057), compared to captive NHPs, suggesting that parasite transmission in NHPs occurs more actively in the sylvatic cycle. In terms of primate family, Pitheciidae had the highest trypanosomatid prevalence (20/22, 90.9%) and Cebidae had the highest T. cruzi prevalence (15/117, 12.8%). T. cruzi and trypanosomatids are common in Peruvian NHPs and could pose a health risk to human and animals that has not been properly studied.

Sylvatic host associations of Triatominae and implications for Chagas disease reservoirs: a review and new host records based on archival specimens

BACKGROUND

The 152 extant species of kissing bug include important vectors of the debilitating, chronic, and often fatal Chagas disease, which affects several million people mainly in Central and South America. An understanding of the natural hosts of this speciose group of blood-feeding insects has and will continue to aid ongoing efforts to impede the spread of Chagas disease. However, information on kissing bug biology is piecemeal and scattered, developed using methods with varying levels of accuracy over more than 100 years. Existing host records are heavily biased towards well-studied primary vector species and are derived from primarily three different types of observations, associational, immunological or DNA-based, with varying reliability.

METHODS

We gather a comprehensive and unparalleled number of sources reporting host associations via rigorous targeted searches of publication databases to review all known natural, or sylvatic, host records including information on how each record was collected. We integrate this information with novel host records obtained via attempted amplification and sequencing of a ∼160 base pair (bp) region of the vertebrate 12S mitochondrial gene from the gastrointestinal tract of 64 archival specimens of Triatominae representing 19 species collected primarily in sylvatic habitats throughout the southern United States and Central and South America during the past 10 years. We show the utility of this method for uncovering novel and under-studied groups of Triatominae hosts, as well as detecting the presence of the Chagas disease pathogen via Polymerase Chain Reaction (PCR) of a ∼400 bp sequence of the trypanosome 18S gene.

RESULTS

New host associations for several groups of arboreal mammals were determined including sloths, New World monkeys, coatis, arboreal porcupines and, for the first time as a host of any Triatominae, tayras. A thorough review of previously documented sylvatic hosts, organized by triatomine species and the type of observation (associational, antibody-based, or DNA-based), is presented in a phylogenetic context and highlights large gaps in our knowledge of Triatominae biology.

CONCLUSION

The application of DNA-based methods of host identification towards additional species of Triatominae, including rarely collected species that may require use of archival specimens, is the most efficient and promising way to resolve recognized shortfalls.

Within-host temporal fluctuations of Trypanosoma cruzi discrete typing units: the case of the wild reservoir rodent Octodon degus

Background

Chagas disease caused by Trypanosoma cruzi is considered a major public health problem in America. After an acute phase the disease changes to a chronic phase with very low parasitemia. The parasite presents high genetic variability with seven discrete typing units (DTUs): TcI-TcVI and Tc bat. The aim of this work is to evaluate fluctuation of parasitemia and T. cruzi DTUs in naturally infected Octodon degus.

Methods

After animal capture parasitemia was obtained by qPCR and later the animals were evaluated by three serial xenodiagnoses using two insect vector species, Mepraia spinolai and Triatoma infestans. The parasites amplified over time by insect xenodiagnosis were analyzed by conventional PCR and after that the infective T. cruzi were characterized by means of hybridization tests.

Results

The determination of O. degus parasitemia before serial xenodiagnosis by qPCR reveals a great heterogeneity from 1 to 812 parasite equivalents/ml in the blood stream. The T. cruzi DTU composition in 23 analyzed animals by xenodiagnosis oscillated from mixed infections with different DTUs to infections without DTU identification or vice versa, this is equivalent to 50% of the studied animals. Detection of triatomine infection and composition of T. cruzi DTUs was achieved more efficiently 40 days post-infection rather than after 80 or 120 days.

Conclusion

Trypanosoma cruzi DTUs composition fluctuates over time in naturally infected O. degus. Three replicates of serial xenodiagnosis confirmed that living parasites have been studied. Our results allow us to confirm that M. spinolai and T. infestans are equally competent to maintain T. cruzi DTUs since similar results of infection were obtained after xenodiagnosis procedure.

Identification of novel mammalian hosts and Brazilian biome geographic distribution of Trypanosoma cruzi TcIII and TcIV

Trypanosoma cruzi is a parasitic protozoan responsible for Chagas disease. Seven different Discrete Typing Units (DTUs) of T. cruzi are currently identified in nature: TcI-TcVI, and TcBat whose distribution patterns in nature, hosts/reservoirs and eco-epidemiological importance are still little known. Here, we present novel data on the geographic distribution and diversity of mammalian hosts and vectors of T. cruzi DTUs TcIII and TcIV. In this study, we analyzed 61 T. cruzi isolates obtained from 18 species of mammals (five orders) and two Hemiptera genera. Samples were collected from five Brazilian biomes (Pantanal, Caatinga, Cerrado, Atlantic Rainforest, and Amazon) previously characterized as Z3 or mixed infection (TcI-Z3) by mini-exon gene PCR. To identify TcIII and TcIV genotypes, we applied restriction fragment length polymorphism analysis to the PCR-amplified histone 3 gene. DTUs TcIII and TcIV were identified in single and mixed infections from wide dispersion throughout five Brazilian biomes studied, with TcIV being the most common. Pantanal was the biome that displayed the largest number of samples characterized as TcIII and TcIV in single and mixed infections, followed by Atlantic Rainforest and Amazon. Species from the Didelphimorphia order displayed the highest frequency of infection and were found in all five biomes. We report, for the first time, the infection of a species of the Artiodactyla order by DTU TcIII. In addition, we describe new host species: five mammals (marsupials and rodents) and two genera of Hemiptera. Our data indicate that DTUs TcIII and TcIV are more widespread and infect a larger number of mammalian species than previously thought. In addition, they are transmitted in restricted foci and cycles, but in different microhabitats and areas with distinct ecological profiles. Finally, we show that DTUs TcIII and TcIV do not present any specific association with biomes or host species.

Modelling the influence of host community composition in a sylvatic Trypanosoma cruzi system

Species composition of wild reservoir hosts can influence the transmission and maintenance of multi-host vector borne pathogens. The 'pace of life' hypothesis proposes that the life history strategy of reservoir hosts can influence pathogen transmission of vector borne generalist pathogens. We use empirical data to parameterize a mathematical model that investigates the impacts of host life history traits on vector transmission dynamics of the vector-borne multi-host parasite Trypanosoma cruzi in habitats characterized by different degrees of deforestation and varying host community structure. The model considers susceptible and infected vector and host populations. When comparing the proportion of vectors infected with T. cruzi predicted by the model with empirical data, we found a trend of increasing vector infection as anthropogenic landscape disturbance increases for both data and model output. The model's vector infection rates were significantly lower than empirical results, but when incorporating host congenital transmission in the model, vector infection approaches field data. We conclude that intervened habitats associated with r-selected host species communities predict higher proportions of infected vectors.

Trypanosoma cruzi (Agent of Chagas Disease) in Sympatric Human and Dog Populations in "Colonias" of the Lower Rio Grande Valley of Texas

AbstractThe zoonotic, vector-borne parasite Trypanosoma cruzi causes Chagas disease throughout the Americas, but human and veterinary health burdens in the United States are unknown. We conducted a cross-sectional prevalence study in indigent, medically underserved human and cohabiting canine populations of seven south Texas border communities, known as colonias. Defining positivity as those samples that were positive on two or more independent tests, we found 1.3% seroprevalence in 233 humans, including one child born in the United States with only short-duration travel to Mexico. Additionally, a single child with no travel outside south Texas was positive on only a single test. Among 209 dogs, seroprevalence was 19.6%, but adjusted to 31.6% when including those dogs positive on only one test and extrapolating potential false negatives. Parasite DNA was detected in five dogs, indicating potential parasitemia. Seropositive dogs lived in all sampled colonias with no difference in odds of positivity across age, sex, or breed. Colonia residents collected two adult Triatoma gerstaeckeri and one nymph triatomine from around their homes; one of three bugs was infected with T. cruzi, and blood meal hosts were molecularly determined to include dog, human, and raccoon. Dogs and the infected vector all harbored T. cruzi discrete typing unit I, which has previously been implicated in human disease in the United States. Colonias harbor active T. cruzi transmission cycles and should be a priority in outreach and vector control initiatives.

Lineage-specific serology confirms Brazilian Atlantic forest lion tamarins, Leontopithecus chrysomelas and Leontopithecus rosalia, as reservoir hosts of Trypanosoma cruzi II (TcII)

Background

Trypanosoma cruzi, the agent of Chagas disease in humans, has a vast reservoir of mammalian hosts in the Americas, and is classified into six genetic lineages, TcI-TcVI, with a possible seventh, TcBat. Elucidating enzootic cycles of the different lineages is important for understanding the ecology of this parasite, the emergence of new outbreaks of Chagas disease and for guiding control strategies. Direct lineage identification by genotyping is hampered by limitations of parasite isolation and culture. An indirect method is to identify lineage-specific serological reactions in infected individuals; here we describe its application with sylvatic Brazilian primates.

Methods

Synthetic peptides representing lineage-specific epitopes of the T. cruzi surface protein TSSA were used in ELISA with sera from Atlantic Forest Leontopithecus chrysomelas (golden-headed lion tamarin), L. rosalia (golden lion tamarin), Amazonian Sapajus libidinosus (black-striped capuchin) and Alouatta belzebul (red-handed howler monkey).

Results

The epitope common to lineages TcII, TcV and TcVI was recognised by sera from 15 of 26 L. chrysomelas and 8 of 13 L. rosalia. For 12 of these serologically identified TcII infections, the identity of the lineage infection was confirmed by genotyping T. cruzi isolates. Of the TcII/TcV/TcVI positive sera 12 of the 15 L. chrysomelas and 2 of the 8 L. rosalia also reacted with the specific epitope restricted to TcV and TcVI. Sera from one of six S. libidinous recognised the TcIV/TcIII epitopes.

Conclusions

This lineage-specific serological surveillance has verified that Atlantic Forest primates are reservoir hosts of at least TcII, and probably TcV and TcVI, commonly associated with severe Chagas disease in the southern cone region of South America. With appropriate reagents, this novel methodology is readily applicable to a wide range of mammal species and reservoir host discovery.

Possible Differences in the Effects of Trypanosoma cruzi on Blood Cells and Serum Protein of Two Wildlife Reservoirs

A key step in the dynamics of vector-borne diseases is the role of seasonality. Trypanosoma cruzi is a protozoan that causes Chagas disease. Some wild mammals are considered natural hosts, yet not all mammals show the same response to infection. We explored the effect of T. cruzi on blood parameters in two mammal carnivores, coati (Nasua narica) and raccoon (Procyon lotor), that were naturally infected in summer and winter seasons. The study was carried out in the Zoological Park "Parque Museo de la Venta," in Southeastern Mexico. Blood samples were collected in summer and winter from 2010 to 2013. Parasite infection was assessed by PCR from whole blood, and a complete hemogram was determined by traditional manual methods. We found that both species had the same T. cruzi I lineage. For coatis, mean corpuscular volume, mean corpuscular hemoglobin, and monocytes were dependent of season, while eosinophils and plasma proteins were significantly different, but with no season effect. For raccoon, erythrocytes, mean corpuscular volume, mean corpuscular hemoglobin, and monocytes were dependent of season. These results and a previous study that indicated interspecific differences in parasitemia in both species suggest that raccoon is a better reservoir than coati. Such a different interspecific response implies that animals do not contribute equally to maintain T. cruzi parasites in the ecosystem. Such inequality differs according to season.

Ecological scenario and Trypanosoma cruzi DTU characterization of a fatal acute Chagas disease case transmitted orally (Espírito Santo state, Brazil)

BACKGROUND

Trypanosoma cruzi infection via oral route results in outbreaks or cases of acute Chagas disease (ACD) in different Brazilian regions and poses a novel epidemiological scenario. In the Espírito Santo state (southeastern Brazil), a fatal case of a patient with ACD led us to investigate the enzootic scenario to avoid the development of new cases. At the studied locality, Triatoma vitticeps exhibited high T. cruzi infection rates and frequently invaded residences.

METHODS

Sylvatic and domestic mammals in the Rio da Prata locality, where the ACD case occurred, and in four surrounding areas (Baia Nova, Buenos Aires, Santa Rita and Todos os Santos) were examined and underwent parasitological and serological tests. Triatomines were collected for a fecal material exam, culturing and mini-exon gene molecular characterization, followed by RFLP-PCR of H3/Alul. Paraffin-embedded cardiac tissue of a patient was washed with xylene to remove paraffin and DNA was extracted using the phenol-chloroform method. For genotype characterization, PCR was performed to amplify the 1f8, GPI and 18S rRNA genes. In the case of V7V8 SSU rRNA, the PCR products were molecularly cloned. PCR products were sequenced and compared to sequences in GenBank. Phylogenetic analysis using maximum likelihood method with 1000 bootstrap replicates was performed.

RESULTS

None of the animals showed positive hemocultures. Three rodents and two dogs showed signs of infection, as inferred from borderline serological titers. T. vitticeps was the only triatomine species identified and showed T. cruzi infection by DTUs TcI and TcIV. The analysis of cardiac tissue DNA showed mixed infection by T. cruzi (DTUs I, II, III and IV) and Trypanosoma dionisii.

CONCLUSIONS

Each case or outbreak of ACD should be analyzed as a particular epidemiological occurrence. The results indicated that mixed infections in humans may play a role in pathogenicity and may be more common than is currently recognized. Direct molecular characterization from biological samples is essential because this procedure avoids parasite selection. T. dionisii may under certain and unknown circumstances infect humans. The distribution of T. cruzi DTUS TcIII and TcIV in Brazilian biomes is broader than has been assumed to date.

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.

Complexity and multi-factoriality of Trypanosoma cruzi sylvatic cycle in coatis, Nasua nasua (Procyonidae), and triatomine bugs in the Brazilian Pantanal

Background

Trypanosoma cruzi is dispersed in nature through many transmission mechanisms among a high diversity of vectors and mammalian species, representing particular behaviors and habitats. Thus, each locality has a unique set of conditions underlying the maintenance of this parasite in the wild. The aim of the present study was to evaluate the life-cycle of T. cruzi in free-ranging coatis from the central region of the Brazilian Pantanal using a multi-factorial approach.

Methods

Three methodological blocks were used in the present study: (i) We evaluated T. cruzi infection using serological (ELISA) and parasitological (hemoculture) tests in free-ranging coatis captured from October 2010 to March 2012. In addition, we characterized T. cruzi isolates as DTUs (Discrete Typing Units); (ii) We evaluated Trypanosoma infection in species of Triatoma and Rhodnius inhabiting coati arboreal nests from May to September 2012 using parasitological and molecular assays; and (iii) We analyzed a set of longitudinal data (from 2005 to 2012) concerning the effects of T. cruzi infection on this coati population. Herein, we investigated whether seasonality, host sex, and host age influence T. cruzi prevalence and patterns of infection.

Results

The 2010–2012 period presented high seroprevalence on coatis (72.0 % ELISA) and a high percentage of individuals with infectivity competence (20.5 % positive hemoculture). All isolates presented TcI band patterns, occurring in single (n = 3) and mixed infections (1 TcI/T. rangeli; 4 with undefined characterization). Both male and female individuals presented the same transmission potential, expressed as positive hemoculture, which was only detected in the summer. However, overall, the data (2005–2012) highlighted the importance of females for T. cruzi maintenance in the winter. Moreover, twenty-three (67.6 %) bugs from five coati nests (71.4 %) were infected with flagellated forms. Seventeen samples were characterized as T. cruzi (TcI and TcIII genotypes).

Conclusion

In the Pantanal region, T. cruzi is transmitted in a complex, multifactorial, dynamic and non-linear transmission web. The coati nests might be inserted in this web, acting as important transmission foci at the arboreal stratum to different mammal species with arboreal or scansorial behavior.

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.

Triatominae (Hemiptera, Reduviidae) in the Pantanal region: association with Trypanosoma cruzi, different habitats and vertebrate hosts

INTRODUCTION

The transmission cycle of Trypanosoma cruzi in the Brazilian Pantanal region has been studied during the last decade. Although considerable knowledge is available regarding the mammalian hosts infected by T. cruzi in this wetland, no studies have investigated its vectors in this region. This study aimed to investigate the presence of sylvatic triatomine species in different habitats of the Brazilian Pantanal region and to correlate their presence with the occurrences of vertebrate hosts and T. cruzi infection.

METHODS

The fieldwork involved passive search by using light traps and Noireau traps and active search by visual inspection. The light traps were placed at five selected points along forested areas for seven nights during each of the nine excursions. At each point where a light trap was set, eight Noireau traps were placed in palm trees and bromeliads.

RESULTS

In all, 88 triatomine bugs were collected: two and one individuals from light traps and Noireau traps, respectively; three from peridomestic areas; 23 in coati nests; and 59 in thornbird nests. In this study, active search in microhabitats showed higher efficiency than passive search, since 95% of the triatomine bugs were caught in nests. Further, triatomine bugs were only found to be infected by T. cruzi in coati nests.

CONCLUSIONS

Coati nests might act as a point of convergence and dispersion for triatomine bugs and mammal hosts infected by T. cruzi, thereby playing an important role in the sylvatic cycle of T. cruziin the Pantanal region.

Co-Infection and Wild Animal Health: Effects of Trypanosomatids and Gastrointestinal Parasites on Coatis of the Brazilian Pantanal

Wild animals are infected by diverse parasites, but how they influence host health is poorly understood. We examined the relationship of trypanosomatids and gastrointestinal parasites with health of wild brown-nosed coatis (Nasua nasua) from the Brazilian Pantanal. We used coati body condition and hematological parameters as response variables in linear models that were compared using an information theoretic approach. Predictors were high/low parasitemias by Trypanosoma cruzi and T. evansi, and indices representing the abundance of distinct groups of gastrointestinal parasites. We also analyzed how host health changed with host sex and reproductive seasonality. Hemoparasites was best related to coati body condition and hematological indices, whereas abundance of gastrointestinal parasites was relatively less associated with coati health. Additionally, some associations were best predicted by models that incorporated reproductive seasonality and host sex. Overall, we observed a lower health condition during the breeding season, when coatis are under reproductive stress and may be less able to handle infection. In addition, females seem to handle infection better than males. Body condition was lower in coatis with high parasitemias of T. evansi, especially during the reproductive season. Total red blood cell counts, packed cell volume, platelets and eosinophils were also lower in animals with high T. evansi parasitemias. Total white blood cell counts and mature neutrophils were lower in animals with high parasitemias for both Trypanosoma species, with neutrophils decreasing mainly during the reproductive season. Overall, decreases in hematological parameters of females with T. evansi high parasitemias were less evident. For T. cruzi, monocytes decreased in individuals with high parasitemias. High abundances of microfilariae in the bloodstream, and cestode eggs and coccidian oocysts in feces were also associated with coati blood parameters. This study shows the potential value of examining hematological parameters as an approach to better understand the ecological relevance of parasite-host interactions.