A major challenge of eco-epidemiology is to determine which factors promote the transmission of infectious diseases and to establish risk maps that can be used by public health authorities. The ...geographic predictions resulting from ecological niche modelling have been widely used for modelling the future dispersion of vectors based on the occurrence records and the potential prevalence of the disease. The establishment of risk maps for disease systems with complex cycles such as cutaneous leishmaniasis (CL) can be very challenging due to the many inference networks between large sets of host and vector species, with considerable heterogeneity in disease patterns in space and time. One novelty in the present study is the use of human CL cases to predict the risk of leishmaniasis occurrence in response to anthropogenic, climatic and environmental factors at two different scales, in the Neotropical moist forest biome (Amazonian basin and surrounding forest ecosystems) and in the surrounding region of French Guiana. With a consistent data set never used before and a conceptual and methodological framework for interpreting data cases, we obtained risk maps with high statistical support. The predominantly identified human CL risk areas are those where the human impact on the environment is significant, associated with less contributory climatic and ecological factors. For both models this study highlights the importance of considering the anthropogenic drivers for disease risk assessment in human, although CL is mainly linked to the sylvatic and peri-urban cycle in Meso and South America.
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 reinforces ecological degradation and carelessness in the face of the possibility of the emergence and spreading of new diseases, such as COVID-19. Tackling the socio-ecological complexity inherent in the risk of the emergence of infectious diseases requires robust co-construction of scientific knowledge, eco-social approaches, and corresponding governance and sophisticated decision-making arrangements.
BACKGROUNDTrypanosomatids 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. OBJECTIVEWe 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. METHODSAnimals 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. FINDINGSDiversity was higher in forests with planting and lower around residences. In total, 135 mammals (81 rodents and 54 marsupials covering 14 genera) were captured. Rodents presented infection rates (IR) of 74% and marsupials of 48%. Rodents in domicile landscapes presented a higher IR (92.9%), while marsupials showed a higher IR in forests (53.3%). MAIN CONCLUSIONSThe results suggest high prevalence of trypanosomatids across 12 mammalian genera possibly involved as reservoir hosts in the enzootic transmission of leishmaniasis in the Amazon's rural, peridomiciliar landscape.
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.
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.
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).
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.
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.
Bats 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.
In 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.
We found that deforested sites had a less diverse bat community than forested sites, but higher viral prevalence and richness after controlling for confounding factors. Viral detection was more likely in juvenile males located in deforested sites. Interestingly, we also found a significant effect of host bat species on viral prevalence indicating that viral taxa were detected more frequently in some species than others. In particular, viruses from the
family were detected more frequently in generalist species compared to specialist species.
Our findings suggest that deforestation may drive changes in the ecosystem which reduce bat host diversity while increasing the abundance of generalist species which host a wider range of viruses.
West Nile virus surveillance, Brazil, 2008―2010 OMETTO, Tatiana; DURIGON, Edison Luiz; SIMAO NETO, Isaac ...
Transactions of the Royal Society of Tropical Medicine and Hygiene,
11/2013, Letnik:
107, Številka:
11
Journal Article
Recenzirano
West Nile virus (WNV) is an emergent pathogen that is widely distributed in North and Central America. The recent introduction in South America has focused attention on the spread of WNV across ...Southern American countries. The transmission network involves mosquitoes, birds, horses and humans.
The serological evaluation of sera from 678 equids and 478 birds was performed using a WNV-specific blocking ELISA, and only the positive results were confirmed by plaque reduction neutralisation tests (PRNTs). Molecular analysis was performed on sera from 992 healthy equids and on 63 macerates of brains from equids that died of encephalitis and had previously tested negative for other pathogens. We also tested swabs from 928 birds. The samples analysed were collected in different biomes of Brazil.
We identified WNV antibodies by ELISA in thirteen equids and five birds, and PRNT90 confirmed WNV positivity in four equid samples collected in 2009 in an area between the Amazon and the Pantanal. None of the ELISA positive bird samples were confirmed by PRNT90, and all samples tested by RT-PCR were negative.
WNV circulation is confirmed by this large scale survey even in the absence of detection of clinical cases.
Morro do Diabo State Park (MDSP) is a significant remnant of the Atlantic Rain Forest in Brazil and is surrounded by rural properties. In that area, wild and domestic animals and humans are in close ...contact, which facilitates the two-way flow of infectious diseases among them. We assessed endoparasites in domestic livestock from all rural properties surrounding MDSP. There were sampled 197 cattle, 37 horses, 11 sheep, 25 swine, 21 dogs, one cat and 62 groups of chickens from 10 large private properties and 75 rural settlements. Eimeria spp. was present in almost all hosts, excepted in horses, dogs and cats. Giardia cysts were present only in cattle. Nematodes were found in swine, ruminants and horses in high prevalence. Ancylostoma, Toxocara and Sarcocystis were found in dogs. Chickens were found with coccidia, Ascaridida and Capillaria spp.. These parasites can cause malnutrition and reproductive disorders for their hosts. Strategies to prevent and control the spread of endoparasites can improve wildlife, animal and human health in this area.
Bats are important reservoirs and spreaders of pathogens. Giardia duodenalis is a globally important protozoan that infects humans and other mammals with considerable public health burden, ...particularly on the child development. Based on genetic variation and host specificity, G. duodenalis is categorized into eight genotypes/assemblages A-H. Assemblages A and B are widespread globally and are associated with human and animal disease. There is evidence of Giardia in the bat feces from diverse geographic regions, but the G. duodenalis assemblages are unknown, which is a key point for the One Health view. Here, we successfully amplified the BG/GDH/DIS3/HCMP2/HCMP3 targets of G. duodenalis from five bat species captured in the Brazilian Amazon biome revealing the presence of zoonotic G. duodenalis assemblages A and B in the feces of these flying mammals. Our study reveals that bats may play a role in transmission of zoonotic G. duodenalis, at least in this biome.
Serum samples from 19 jaguars (
Panthera onca
), nine pumas (
Puma concolor
), and two ocelots (
Leopardus pardalis
) were collected between January 1999 and March of 2005 and tested for presence of ...canine distemper virus (CDV). All cats were free-ranging animals living in two protected areas in the Brazilian Atlantic Forest. In addition, 111 domestic dogs from nearby areas were sampled for CDV. Our results show the first evidence of CDV exposure in Brazilian free-ranging felids. From the 30 samples analyzed, six jaguars and one puma were tested seropositive for CDV. All seropositive large felids were from Ivinhema State Park, resulting in 31.5% of the sampled jaguars or 60% of the total jaguar population in Ivinhema State Park, and 11.28% of the sampled pumas. From the total 111 domestic dogs sampled, 45 were tested seropositive for CDV. At Morro do Diabo State Park, 34.6% of the dogs sampled were positive for CDV, and 100% at Ivinhema State Park. Canine distemper virus in wild felids seems to be related with home range use and in close association with domestic dogs living in nearby areas.
The pied tamarin, or
Saguinus bicolor
, is a callitrichid that inhabits Amazon Forest fragments encased within the municipalities of Manaus, Rio Preto da Eva, and Itacoatiara and their outskirts. ...Therefore, this primate lives in great proximity to humans, and is in critical danger of extinction, resulting from ongoing anthropogenic pressures, with habitat fragmentation being the most prominent threat. Greater conservation efforts and more studies concerning public health need to be carried out in this situation, such as the study of infectious diseases that can affect this primate, including those involving helminths. In this study, we combined necropsy, microscopy with blood smears and quick Panoptic stains, and molecular methods like nested polymerase chain reaction (PCR) targeting the internal transcribed spacer-1 (ITS-1) region, Sanger sequencing and shotgun sequencing to detect and identify filarial parasites in 71
S. bicolor
samples. We detected 24 adult filarial worms in 6.45% of the thoracic cavities, microfilaria in 6.38% from blood smears, and filarial DNA in 28.57% positive blood samples via PCR. We identified eight of the adult worms as being from the Onchocercidae family using Sanger sequencing and one specifically as Dipetalonema gracile, using shotgun sequencing. For the positive blood samples, 70.58% of them were for Mansonella sp., 17.64% for
Dipetalonema
sp., and 11.76% could only be identified as belonging to the Onchocercidae family. There was an event of coinfection that involved
Dipetalonema
sp. adult worm and
Mansonella
sp. microfilaria. This is the first report of the detection of
Dipetalonema gracile
and the genus
Mansonella
in
S. bicolor
, as well as an event of coinfection, pointing out this primate as a new host. It is also another step to understand the situation of filarial infections occurring in Amazonian Regions and its municipalities.
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