Vector-borne transmission of Trypanosoma cruzi among captive Neotropical primates in a Brazilian zoo

Background: Neotropical primates are important sylvatic hosts of Trypanosoma cruzi, the etiological agent of Chagas disease. Infection is often subclinical, but severe disease has been described in both free-ranging and captive primates. Panstrongylus megistus, a major T. cruzi vector, was found infesting a small-primate unit at Brasília zoo (ZooB), Brazil. ZooB lies close to a gallery-forest patch where T. cruzi circulates naturally. Here, we combine parasitological and molecular methods to investigate a focus of T. cruzi infection involving triatomine bugs and Neotropical primates at a zoo located in the Brazilian Savannah. Methods: We assessed T. cruzi infection in vectors using optical microscopy (n = 34) and nested PCR (n = 50). We used quantitative PCR (qPCR) to examine blood samples from 26 primates and necropsy samples from two primates that died during the study. We determined parasite lineages in five vectors and two primates by comparing glucose-6-phosphate isomerase (G6pi) gene sequences. Results: Trypanosoma cruzi was found in 44 vectors and 17 primates (six genera and eight species); one Mico chrysoleucus and one Saguinus niger had high parasitaemias. Trypanosoma cruzi DNA was detected in three primates born to qPCR-negative mothers at ZooB and in the two dead specimens. One Callithrix geoffroyi became qPCR-positive over a two-year follow-up. All G6pi sequences matched T. cruzi lineage TcI. Conclusions: Our findings strongly suggest vector-borne T. cruzi transmission within a small-primate unit at ZooB – with vectors, and perhaps also parasites, presumably coming from nearby gallery forest. Periodic checks for vectors and parasites would help eliminate T. cruzi transmission foci in captive-animal facilities. This should be of special importance for captive-breeding programs involving endangered mammals, and would reduce the risk of accidental T. cruzi transmission to keepers and veterinarians

Repercussion of COVID-19 pandemic on Brazilians’ quality of life : a nationwide cross-sectional study

The COVID-19 outbreak, caused by Sars-Cov-2, was officially declared a global pandemic in February 2020, after an unexpected increase in hospitalization and mortality. When faced with this new disease, social and physical distancing and quarantine emerged as solutions to reduce virus transmission. This article examines the quality of life (QoL) of the Brazilian population’s during this period of isolation, due to the COVID-19 pandemic by analyzing; physical, psychological, social, and economic aspects. An online survey was distributed from 27 May to 14 August of 2020. A total of 1859 surveys were completed. Our results indicate that Brazilians were more affected by economic and social aspects than psychological and physical. Unemployed participants and individuals who tested positive for COVID-19 presented the lowest QoL. Females showed worst QoL scores than males, but having children did not influence the score. Higher educational level was associated with a better perception of QoL. Not following social distancing guidelines presented better scores in the psychological domain than the ones following restrict or partial social distancing rules. This study is the first to evaluate adults’ QoL related to the Sars-Cov-2 pandemic in Brazil at a national level. Our data may help health authorities identify the main factors affecting the QoL of the Brazilian population, thereby orientating them to recover after the pandemic

The first Acanthamoeba keratitis case in the Midwest region of Brazil: diagnosis, genotyping of the parasite and disease outcome

We report an Acanthamoeba keratitis case associated with the use of contact lens in a 28-year-old female from Brasília, Brazil. Samples from corneal scraping and contact lens case were used for culture establishment, PCR amplification, and partial sequencing (fragments of ~400kb) of small subunit rDNA; both culture and PCR were positive. The sequence analyses of the cornea and of isolates from the contact lens case showed similarity with the T4 genotype. To the best of our knowledge, this is the first report of T4 Acanthamoeba keratitis case from the Midwest region of Brazil

Expanding the knowledge about Leishmania species in wild mammals and dogs in the Brazilian savannah

Background: Wild, synanthropic and domestic mammals act as hosts and/or reservoirs of several Leishmania spp. Studies on possible reservoirs of Leishmania in different areas are fundamental to understand host-parasite interactions and develop strategies for the surveillance and control of leishmaniasis. In the present study, we evaluated the Leishmania spp. occurrence in mammals in two conservation units and their surroundings in Brasília, Federal District (FD), Brazil. Methods: Small mammals were captured in Brasília National Park (BNP) and Contagem Biological Reserve (CBR) and dogs were sampled in residential areas in their vicinity. Skin and blood samples were evaluated by PCR using different molecular markers (D7 24Sα rRNA and rDNA ITS1). Leishmania species were identified by sequencing of PCR products. Dog blood samples were subjected to the rapid immunochromatographic test (DPP) for detection of anti-Leishmania infantum antibodies. Results: 179 wild mammals were studied and 20.1% had Leishmania DNA successfully detected in at least one sample. Six mammal species were considered infected: Clyomys laticeps, Necromys lasiurus, Nectomys rattus, Rhipidomys macrurus, Didelphis albiventris and Gracilinanus agilis. No significant difference, comparing the proportion of individuals with Leishmania spp., was observed between the sampled areas and wild mammal species. Most of the positive samples were collected from the rodent N. lasiurus, infected by L. amazonensis or L. braziliensis. Moreover, infections by Trypanosoma spp. were detected in N. lasiurus and G. agilis. All 19 dog samples were positive by DPP; however, only three (15.8%) were confirmed by PCR assays. DNA sequences of ITS1 dog amplicons showed 100% identity with L. infantum sequence. Conclusions: The results suggest the participation of six species of wild mammals in the enzootic transmission of Leishmania spp. in FD. This is the first report of L. amazonensis in N. lasiurus

Transferência horizontal de seqüências de minicírculos de kDNA de Trypanosoma cruzi para o genoma de chagásicos e herança vertical das mutações

Tese (doutorado)—Universidade de Brasília, Faculdade de Medicina, 2008.Neste estudo, nós confirmamos e estendemos o conhecimento sobre a transferência de minicírculos de kDNA de Trypanosoma cruzi para o genoma humano. Foram analisadas cinco famílias cujos parentais (G0) eram portadores da doença de Chagas. Foi possível observar a integração de kDNA de T. cruzi no genoma de todos os chagásicos estudados. Concomitantemente, investigamos a transferência gênica vertical (TGV) das seqüências integradas de kDNA para as progênies G1 e G2. A TGV foi identificada em 45% dos descendentes de chagásicos. As análises das regiões do genoma humano que flanqueavam as seqüências de kDNA mostraram a integração de minicírculos de kDNA preferencialmente em retrotransposons LINE (71% dos clones). As integrações foram identificadas também em retroelementos não-autonônomos (12%), em ilha CpG (1%) e em alguns genes (4%). Nos demais clones (12%), não foi possível determinar os loci de integração do kDNA no genoma. A análise da estrutura do kDNA integrado revelou duas seqüências consensos de minicírculos que são inseridas mais freqüentemente que as outras, sugerindo que suas características estruturais possam favorecer o processo de integração. Acreditamos que micro-homologias ricas em AC, presentes nos minicírculos do T. cruzi e no genoma humano, podem mediar a integração do kDNA por recombinação homóloga. Os nossos achados sugerem remodelagem do genoma hospedeiro na região de justaposição das seqüências de minicírculos de kDNA no genoma humano. As análises in silico sugerem que o fenômeno descrito aqui pode resultar no surgimento de novas proteínas ou na alteração de expressão de genes pré-existentes. O real significado de tais mutações não fica restrito à Doença de Chagas, mas, sim, estende-se ao longo do processo da evolução, onde a fixação dessas mutações ajudaria a impulsionar um fluxo genético introdutor de complexidade crescente às espécies.In this study we showed the transference of Trypanosoma cruzi kDNA minicircle sequences into the human genome. All founders (G0) of five families having the chronic T. cruzi infections had the kDNA integrated into retrotransposable elements. Additionally, we demonstrated the vertical gene transfer (VGT) of those kDNA mutations to their G1 e G2 progenies. Indeed, VGT was demonstrated in 45% of Chagas patients’ descendents. The analyses of the juxtaposition regions of the kDNA to the human genome revealed that the minicircle sequences integrate preferentially into retrotransposable LINE in 71% of those mutations. These mutations were also present in non-authonomous retroelements (12%), CpG island (1%) and putatively in some genes (4%). The remaining mutations (12%) were present in undetermined loci in some chromosomes. The structure of the kDNA integrated into the host genome revealed main consensus types I and II sequences, which were found in the integration sites in high ratio then other minicircles integrated in defined loci. It appears that some particular feature in those consensus sequences favor their insertion in those loci. We believe that AC-rich micro-homologies present in the T. cruzi kDNA minicircles and in the human genome could mediate the parasite DNA integration by homologous recombination mechanism. Our findings suggest that host DNA shuffling and recombination may occur at the integration site. It appears that the phenomenon of kDNA integration may alter pre-existing genes expression or they may generate chimera proteins. The true meanings of those mutations appear not to be limited to Chagas disease. We understand that the observed genetic drift of 55% of the kDNA mutation in the progeny may help to propel a robust genetic flux possibly associated with genome growth and increasing complexity of species. We propose that the fixation of those mutations appear to influence the evolution process

Detecting Leishmania in dogs: A hierarchical-modeling approach to investigate the performance of parasitological and qPCR-based diagnostic procedures.

BackgroundDomestic dogs are primary reservoir hosts of Leishmania infantum, the agent of visceral leishmaniasis. Detecting dog infections is central to epidemiological inference, disease prevention, and veterinary practice. Error-free diagnostic procedures, however, are lacking, and the performance of those available is difficult to measure in the absence of fail-safe "reference standards". Here, we illustrate how a hierarchical-modeling approach can be used to formally account for false-negative and false-positive results when investigating the process of Leishmania detection in dogs.Methods/findingsWe studied 294 field-sampled dogs of unknown infection status from a Leishmania-endemic region. We ran 350 parasitological tests (bone-marrow microscopy and culture) and 1,016 qPCR assays (blood, bone-marrow, and eye-swab samples with amplifiable DNA). Using replicate test results and site-occupancy models, we estimated (a) clinical sensitivity for each diagnostic procedure and (b) clinical specificity for qPCRs; parasitological tests were assumed 100% specific. Initial modeling revealed qPCR specificity ConclusionsWe provide statistical estimates of key performance parameters for five diagnostic procedures used to detect Leishmania in dogs. Low clinical sensitivies likely reflect the absence of Leishmania parasites/DNA in perhaps ~50-70% of samples drawn from infected dogs. Although qPCR performance was similar across sample types, non-invasive eye-swabs were overall less likely to contain amplifiable DNA. Finally, modeling was instrumental to discovering (and formally accounting for) possible qPCR-plate contamination; even with stringent negative/blank-control scoring, ~4-5% of positive qPCRs were most likely false-positives. This work shows, in sum, how hierarchical site-occupancy models can sharpen our understanding of the problem of diagnosing host infections with hard-to-detect pathogens including Leishmania