Papers by Alessandra Nava
Research Square (Research Square), May 11, 2023
The zoonotic protozoa parasite Giardia duodenalis infects a wide range of vertebrate hosts, inclu... more The zoonotic protozoa parasite Giardia duodenalis infects a wide range of vertebrate hosts, including domestic and wild animals as well as humans. G.duodenalis is one of the most common intestinal parasite in humans and mammals worldwide. In humans, the disease is called giardiasis, with symptoms such as acute diarrhea which may progress to a chronic stage, but most infections remain asymptomatic. In children, giardiasis has a negative impact on their growth and cognitive development. Zoonotic assemblages A and B have already been identi ed in humans and wild and domestic animals (non-human primates and cats) from Brazilian Amazon. Here, in a screening focusing Giardia identi cation in wild animals from the Brazilian Amazon region, we identi ed, by microscopy, Giardia in two Northern sloths (Bradypus tridactylus). Samples from these two individuals were submitted to molecular assays, PCR targeting the beta giardin gene and amplicon sequencing, and it was revealed that both were infected by G. duodenalisfrom zoonotic assemblage A. In addition, the phylogenetic analysis showed that each one belong to a distinct assemblage A sub-cluster within sequences from humans and animals. Therefore, besides showing, by the rst time, the presence of this parasite in sloths, our ndings reveals that this wild animal species would be part of the zoonotic scenario of this parasite in the Brazilian Amazon.
Mammalian Biology, Mar 1, 2019
In general, habitat fragmentation is associated with a reduction in gene flow that can reduce the... more In general, habitat fragmentation is associated with a reduction in gene flow that can reduce the genetic diversity, and, consequently, a species ability to survive environmental changes. The white-lipped peccary (Tayassu pécari) is a Neotropical ecosystem engineer that is vulnerable throughout its distribution area and under different degrees of threat in the Brazilian Pantanal (near threatened), Cerrado (endangered) and Atlantic Forest (critically endangered). We used 13 microsatellite loci to assess the genetic diversity and population structure of 361 white-lipped peccaries sampled in four areas in the Pantanal, two areas in the Cerrado, and one area in the Atlantic Forest. We found similar levels of genetic diversity in all localities. Bayesian clustering analysis indicated the presence of two (K = 2; all Pantanal localities plus the Cerrado locality at the Pantanal highlands versus the other Cerrado locality plus the Atlantic Forest one) or three (K = 3; with the additional differentiation between the Cerrado locality and the Atlantic Forest) genetically differentiated populations. We found a pattern of isolation by distance (IBD) limited by dispersal events of up to 180 km. This IBD pattern is congruent with gene flow between the geographically closer localities in the Pantanal and the Cerrado in the Pantanal highlands (25–137 km), while dispersal between the other Cerrado locality and the Atlantic Forest, that are 500 km apart, would not be as feasible. Therefore, we considered K = 3 as the best scenario to represent the genetic structure of the populations analyzed. As all populations of white-lipped peccary showed moderate levels of genetic diversity, conservation actions are recommended to maintain their diversity, as it is vital to the long-term viability of these populations, especially those in more threatened biomes.
Revista Brasileira De Parasitologia Veterinaria, Dec 1, 2010
The aim of this study was to assess the occurrence of Cryptosporidium in domestic animals in rura... more The aim of this study was to assess the occurrence of Cryptosporidium in domestic animals in rural properties surrounding rain forest fragments within the municipality of Teodoro Sampaio, southeastern Brazil. Conventional sucrose flotation method followed by molecular characterization of the parasites by sequencing PCR products amplified from SSU rRNA gene were used. Stool samples were collected from domestic animals raised as pets and livestock in all rural properties surrounding three forest fragments. Samples from cattle (197), equine (63), pigs (25), sheep (11), and dogs (28) were collected from 98 rural properties. The frequency of occurrence of Cryptosporidium within each animal species was 3.0% (6/197) among cattle and 10.7% (3/28) among dogs. Cryptosporidium was not detected in stool samples from equine, sheep, and pigs. All sequences obtained from the six samples of calves showed molecular identity with Cryptosporidium andersoni while all sequences from dog samples were similar to C. canis. The frequency of occurrence of Cryptosporidium in these domestic animal species was low. The absence of C. parvum in the present study suggests that the zoonotic cycle of cryptosporidiosis may not be relevant in the region studied. The presence of Cryptosporidium species seldom described in humans may be, otherwise, important for the wild fauna as these animals are a source of infection and dissemination of this protozoan to other animal species. The impact and magnitude of infection by C. andersoni in wild ruminants and C. canis in wild canids have to be assessed in future studies to better understand the actual importance of these species in this region.
Revista Brasileira de Parasitologia Veterinária
The canine filarial parasite Dirofilaria immitis has not been reported in Brazil´s Amazonas state... more The canine filarial parasite Dirofilaria immitis has not been reported in Brazil´s Amazonas state capital, Manaus, for over a century. Here, we report one imported and 27 autochthonous D. immitis infections from a microfilarial survey of 766 domestic dog blood samples collected between 2017 and 2021 in Manaus. An Overall prevalence estimate of 15.44% (23/149) was calculated from our two rural collection sites; a prevalence of 1.22% (4/328) was estimated at our periurban collection site, and an overall prevalence of 0.35% (1/289) was calculated from our two urban clinic collections. Our data suggest that in the urban areas of Manaus, where the parasites are very likely vectored by the same species of mosquito that historically vectored Wuchereria bancrofti (Culex quinquefasciatus), prevalence levels are very low and possibly maintained by an influx from rural areas where sylvatic reservoirs and/or more favorable vector transmission dynamics maintain high prevalences.
Acta Amazonica
The primates that inhabit the rainforest surrounding the city of Manaus (Amazonas, Brazil) have l... more The primates that inhabit the rainforest surrounding the city of Manaus (Amazonas, Brazil) have long been recognised as potentially important reservoirs of emerging and re-emerging infectious diseases (ERIDs). PCR amplification of filarial sequences from wild-caught Simulium oyapockense has been used to incriminate potentially important Amazon-region ERID bridge vectors by showing they had previously fed on non-human primates. The broader use of filarial parasite sequences for the incrimination of biting insects as potentially important zoonotic disease vectors is limited by a paucity of primate-derived filarial parasite reference sequences which can be matched to the PCR amplified sequences obtained from insect-vector vectors. Here we have used shotgun sequencing to obtain reference data from an adult Dipetalonema gracile parasite which was found infecting a wild pied tamarin (Saguinus bicolor) in a peripheral region of Manaus. We report the parasite´s complete mitochondrial genome...
Archives of Virology, 2011
Current knowledge of the pathogenic hantavirus indicates that wild rodents are its primary natura... more Current knowledge of the pathogenic hantavirus indicates that wild rodents are its primary natural reservoir. Specific primers to detect the presence of viral genomes were developed using an SYBR-Green-based real-time RT-PCR protocol. One hundred sixty-four rodents native to the Atlantic Forest biome were captured in São Paulo State, Brazil, and their tissues were tested. The presence of hantavirus RNA was detected in sixteen rodents: three specimens of Akodon montensis, three of Akodon cursor, two of Necromys lasiurus, one of Juliomys sp., one of Thaptomys nigrita, five of Oligoryzomys nigripes, and one of Oryzomys sp. This SYBR Green real-time RT-PCR method for detection of hantavirus may be useful for surveying hantaviruses in Brazil.
Memórias do Instituto Oswaldo Cruz, 2021
BACKGROUND Giardia duodenalis is a protozoan parasite that infects humans and other mammals and c... more BACKGROUND Giardia duodenalis is a protozoan parasite that infects humans and other mammals and causes giardiasis worldwide. Giardia is genotyped into eight assemblages (A-H), with assemblages A and B considered zoonotic. OBJECTIVES The aim of this study was to determine the assemblages of G. duodenalis from individuals living in rural and urban areas of the Amazonas State. METHODS 103 human faecal specimens microscopically positive for the presence of Giardia obtained from four municipalities in Amazonas and four animal faecal specimens were genotyped based on the sequences of two genes, triosephosphate isomerase (TPI) and β-giardin (BG). FINDINGS In humans, assemblage A was the most represented with the identification of sub-assemblages AI, AII and AIII based on BG and sub-assemblages AI and AII based on TPI. Similarly, there is a diversity of sub-assemblage B considering BG (B and BIII) and TPI (B, BIII and BIV). In addition, we characterised homogeneous and heterogeneous genotypes comprising assemblages/sub-assemblages A and B in individuals from urban and rural areas. Here, for the first time, it was genotyped Giardia that infects animals from the Brazilian Amazon region. We identified sub-assemblage AI in one Ateles paniscus and two Felis catus and sub-assemblage BIV in one Lagothrix cana. MAIN CONCLUSIONS Therefore, humans and animals from the urban and rural Amazon share Giardia genotypes belonging to assemblages A and B, which are found in cosmopolitan regions around the world.
Frontiers in Cellular and Infection Microbiology
IntroductionBats are critical to maintaining healthy ecosystems and many species are threatened p... more IntroductionBats are critical to maintaining healthy ecosystems and many species are threatened primarily due to global habitat loss. Bats are also important hosts of a range of viruses, several of which have had significant impacts on global public health. The emergence of these viruses has been associated with land-use change and decreased host species richness. Yet, few studies have assessed how bat communities and the viruses they host alter with land-use change, particularly in highly biodiverse sites.MethodsIn this study, we investigate the effects of deforestation on bat host species richness and diversity, and viral prevalence and richness across five forested sites and three nearby deforested sites in the interior Atlantic Forest of southern Brazil. Nested-PCR and qPCR were used to amplify and detect viral genetic sequence from six viral families (corona-, adeno-, herpes-, hanta-, paramyxo-, and astro-viridae) in 944 blood, saliva and rectal samples collected from 335 bats....
Mammalian Biology, 2019
In general, habitat fragmentation is associated with a reduction in gene flow that can reduce the... more In general, habitat fragmentation is associated with a reduction in gene flow that can reduce the genetic diversity, and, consequently, a species ability to survive environmental changes. The white-lipped peccary (Tayassu pécari) is a Neotropical ecosystem engineer that is vulnerable throughout its distribution area and under different degrees of threat in the Brazilian Pantanal (near threatened), Cerrado (endangered) and Atlantic Forest (critically endangered). We used 13 microsatellite loci to assess the genetic diversity and population structure of 361 white-lipped peccaries sampled in four areas in the Pantanal, two areas in the Cerrado, and one area in the Atlantic Forest. We found similar levels of genetic diversity in all localities. Bayesian clustering analysis indicated the presence of two (K = 2; all Pantanal localities plus the Cerrado locality at the Pantanal highlands versus the other Cerrado locality plus the Atlantic Forest one) or three (K = 3; with the additional di...
Ecology, 2020
Accepted Article This article is protected by copyright. All rights reserved Biological invasion ... more Accepted Article This article is protected by copyright. All rights reserved Biological invasion is one of the main threats to native biodiversity. For a species to become invasive it must be voluntarily or involuntarily introduced by humans into a non-native habitat. Mammals were among first taxa to be introduced worldwide for game, meat and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in southeast USA) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g. Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly due to uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species C. aurita, C. flaviceps, C. geoffroyi, C. jacchus, C. kuhlii, C. penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when use the data in publications. We also request that researchers and teachers inform us on how they are using the data.
PLOS ONE
Many vertebrate species undergo population fluctuations that may be random or regularly cyclic in... more Many vertebrate species undergo population fluctuations that may be random or regularly cyclic in nature. Vertebrate population cycles in northern latitudes are driven by both endogenous and exogenous factors. Suggested causes of mysterious disappearances documented for populations of the Neotropical, herd-forming, white-lipped peccary (Tayassu pecari, henceforth “WLP”) include large-scale movements, overhunting, extreme floods, or disease outbreaks. By analyzing 43 disappearance events across the Neotropics and 88 years of commercial and subsistence harvest data for the Amazon, we show that WLP disappearances are widespread and occur regularly and at large spatiotemporal scales throughout the species’ range. We present evidence that the disappearances represent 7–12-year troughs in 20–30-year WLP population cycles occurring synchronously at regional and perhaps continent-wide spatial scales as large as 10,000–5 million km2. This may represent the first documented case of natural po...
Archives of Virology
As part of a broad One Health surveillance effort to detect novel viruses in wildlife and people,... more As part of a broad One Health surveillance effort to detect novel viruses in wildlife and people, we report several paramyxovirus sequences sampled primarily from bats during 2013 and 2014 in Brazil and Malaysia, including seven from which we recovered full-length genomes. Of these, six represent the first full-length paramyxovirid genomes sequenced from the Americas, including two that are the first full-length bat morbillivirus genome sequences published to date. Our findings add to the vast number of viral sequences in public repositories, which have been increasing considerably in recent years due to the rising accessibility of metagenomics. Taxonomic classification of these sequences in the absence of phenotypic data has been a significant challenge, particularly in the subfamily Orthoparamyxovirinae, where the rate of discovery of novel sequences has been substantial. Using pairwise amino acid sequence classification (PAASC), we propose that five of these sequences belong to m...
Vector-Borne and Zoonotic Diseases, 2017
Bats are reservoir hosts for many paramyxoviruses, some of which cause human and zoonotic disease... more Bats are reservoir hosts for many paramyxoviruses, some of which cause human and zoonotic diseases of public health importance. We developed a Nipah virus nucleoprotein enzyme-linked immunosorbent assay to detect cross-reactive antibodies in serum samples from several bat species in Brazil. Our results warrant further investigation of henipa-like virus reservoirs in the Western hemisphere.
SummaryThe drivers of periodic population cycling by some animal species in northern systems rema... more SummaryThe drivers of periodic population cycling by some animal species in northern systems remain unresolved1. Mysterious disappearances of populations of the Neotropical, herdforming white-lipped peccary (Tayassu pecari, henceforth “WLP”) have been anecdotally documented and explained as local events resulting from migratory movements or overhunting2,3,4, or as disease outbreaks5,6, and have not been considered in the context of large-scale species-specific population dynamics. Here we present evidence that WLP disappearances represent troughs in population cycles that occur with regular periodicity and are synchronized at regional and perhaps continent-wide spatial scales. Analysis of 43 disappearance events and 88 years of commercial and subsistence harvesting data reveals boom – bust population cycles lasting from 20 to 30 years, in which a rapid population crash occurring over 1 to 5 years is followed by a period of absence of 7 to12 years and then a slow growth phase. Overhu...
BACKGROUND Trypanosomatids are widespread and cause diseases - such as trypanosomiasis, sleeping ... more BACKGROUND Trypanosomatids are widespread and cause diseases - such as trypanosomiasis, sleeping sickness, Chagas disease, and cutaneous and visceral leishmaniasis - in animals and humans. These diseases occur in both rural and urban regions due to unplanned growth and deforestation. Thus, wild and synanthropic reservoir hosts living in residential areas are risk factors. OBJECTIVE We aimed to evaluate the diversity of small mammals (rodents and marsupials), and the occurrence of trypanosomatids, especially Leishmania, in the rural settlement of Presidente Figueiredo, Amazonas. METHODS Animals were collected using Sherman, Tomahawk, and Pitfall traps along 16 trails in four landscapes: continuous forest, forest with planting, planting, and peridomiciliar. Leishmania sp. was detected in liver samples by polymerase chain reaction targeting kDNA. FINDINGS Diversity was higher in forests with planting and lower around residences. In total, 135 mammals (81 rodents and 54 marsupials cover...
In this article, we explore elements that highlight the interdependent nature of demands for know... more In this article, we explore elements that highlight the interdependent nature of demands for knowledge production and decision-making related to the appearance of emerging diseases. To this end, we refer to scientific production and current contextual evidence to verify situations mainly related to the Brazilian Amazon, which suffers systematic disturbances and is characterized as a possible source of pathogenic microorganisms. With the acceleration of the Anthropocene's environmental changes, socio-ecological instabilities and the possibility of the emergence of infectious diseases merge into a background of a ´twin insurgency´. Furthermore, there is a tendency to impose economic hegemony in the current Brazilian context, corroborating discourses and pressures to a scientific simplification and denial. With this, we assert that developmental sectoral actions and monoculture of knowledge characterize an agenda of omission, that is, a process of decision making that indirectly re...
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Papers by Alessandra Nava