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1.
Emerg Infect Dis ; 30(5): 1039-1042, 2024 May.
Article in English | MEDLINE | ID: mdl-38666690

ABSTRACT

In Latin America, rabies virus has persisted in a cycle between Desmodus rotundus vampire bats and cattle, potentially enhanced by deforestation. We modeled bovine rabies virus outbreaks in Costa Rica relative to land-use indicators and found spatial-temporal relationships among rabies virus outbreaks with deforestation as a predictor.


Subject(s)
Cattle Diseases , Disease Outbreaks , Rabies virus , Rabies , Animals , Costa Rica/epidemiology , Rabies/epidemiology , Rabies/veterinary , Cattle , Cattle Diseases/epidemiology , Cattle Diseases/virology , Conservation of Natural Resources , Chiroptera/virology , History, 21st Century
2.
BMC Genomics ; 25(1): 34, 2024 Jan 04.
Article in English | MEDLINE | ID: mdl-38177994

ABSTRACT

BACKGROUND: Bats are renowned for harboring a high viral diversity, their characteristics contribute to emerging infectious diseases. However, environmental and anthropic factors also play a significant role in the emergence of zoonotic viruses. Metagenomic is an important tool for investigating the virome of bats and discovering new viruses. RESULTS: Twenty-four families of virus were detected in lung samples by sequencing and bioinfomatic analysis, the largest amount of reads was focused on the Retroviridae and contigs assembled to Desmodus rotundus endogenous retrovirus, which was feasible to acquire complete sequences. The reads were also abundant for phages. CONCLUSION: This lung virome of D. rotundus contributes valuable information regarding the viral diversity found in bats, which is useful for understanding the drivers of viral cycles and their ecology in this species. The identification and taxonomic categorization of viruses hosted by bats carry epidemiological significance due to the potential for viral adaptation to other animals and humans, which can have severe repercussions for public health. Furthermore, the characterization of endogenized viruses helps to understanding the host genome and the evolution of the species.


Subject(s)
Bacteriophages , Chiroptera , Viruses , Animals , Chiroptera/virology , Ecology , Phylogeny , Virome/genetics , Viruses/genetics
3.
Virus Genes ; 59(6): 817-822, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37796410

ABSTRACT

Rabies is worldwide zoonosis caused by Lyssavirus rabies (RABV) a RNA negative sense virus with low level of fidelity during replication cycle. Nucleoprotein of RABV is the most conserved between all five proteins of the virus and is the most used gene for phylogenetic and phylogeographic studies. Despite of rabies been very important in Public Health concern, it demands continuous prophylactic care for herbivores with economic interest, such as cattle and horses. The main transmitter of RABV for these animals in Brazil is the hematophagous bats Desmodus rotundus. The aim of this study was to determine the dispersion over time and space of RABV transmitted by D. rotundus. Samples of RABV from the State of São Paulo (SP), Southeast Brazil isolated from the central nervous system (CNS) of cattle, were submitted to RNA extraction, RT-PCR, sequencing and phylogeographic analyzes with BEAST (Bayesian Evolutionary Analysis Sampling Trees) v 2.5 software. Was possible to identify high rate of diversification in starts sublineages of RABV what are correlated with a behavior of D. rotundus, the main transmitter of rabies to cattle. This study also highlights the importance of continuous monitoring of genetic lineages of RABV in Brazil.


Subject(s)
Chiroptera , Lyssavirus , Rabies virus , Rabies , Animals , Cattle , Rabies/veterinary , Lyssavirus/genetics , Phylogeny , Bayes Theorem , Brazil , RNA
4.
Animals (Basel) ; 13(18)2023 Sep 20.
Article in English | MEDLINE | ID: mdl-37760375

ABSTRACT

Rabies is a fatal neglected tropical zoonosis, and its significance for domestic herbivores in the rural cycle is probably associated with rainforest deforestation, livestock, and agricultural expansion. This epidemiological survey aimed to study the occurrence of rabies in bovines and equines in the state of Rondônia, located in the Brazilian's Legal Amazon, between the years 2002 and 2021, correlating these findings with the prophylactic strategies adopted by the local sanitary agency for rabies control. During this period, 201 cases were observed in bovines and 23 in equines. A downward trend in rabies incidence was observed for both domestic herbivores. Rabies did not show a higher occurrence in any specific time of the year, and epidemic periods varied during some years for bovines and equines. Using the Generalized estimating equations (GEE) method, a multiple model approach was obtained with the explanatory variables significantly associated with the decrease in rabies incidence in cattle and horses during the study period: the ratio of treated bats and ratio of vaccine doses sold. Furthermore, the ratio of printed educative material was positively associated with rabies incidence. Despite a decreasing trend in rabies occurrences in this Amazon rainforest area, likely due to the actions taken by the animal sanitary agency, rabies remains endemic and requires monitoring, as well as prophylactic strategies to control this disease.

5.
Mamm Biol ; : 1-21, 2023 Jun 12.
Article in English | MEDLINE | ID: mdl-37363038

ABSTRACT

The common vampire bat (Desmodus rotundus) maintains a diverse, sanguivorous diet, utilizing a broad range of prey taxa. As anthropogenic change alters the distribution of this species, shifts in predator-prey interactions are expected. Understanding prey richness and patterns of prey selection is, thus, increasingly informative from ecological, epidemiological, and economic perspectives. We reviewed D. rotundus diet and assessed the geographical, taxonomical, and behavioral features to find 63 vertebrate species within 21 orders and 45 families constitute prey, including suitable host species in regions of invasion outside D. rotundus' range. Rodentia contained the largest number of species utilized by D. rotundus, though cattle were the most commonly reported prey source, likely linked to the high availability of livestock and visibility of bite wounds compared to wildlife. Additionally, there was tendency to predate upon species with diurnal activity and social behavior, potentially facilitating convenient and nocturnal predation. Our review highlights the dietary heterogeneity of D. rotundus across its distribution. We define D. rotundus as a generalist predator, or parasite, depending on the ecological definition of its symbiont roles in an ecosystem (i.e., lethal vs. non-lethal blood consumption). In view of the eminent role of D. rotundus in rabies virus transmission and its range expansion, an understanding of its ecology would benefit public health, wildlife management, and agriculture. Supplementary Information: The online version contains supplementary material available at 10.1007/s42991-023-00358-3.

6.
Proc Natl Acad Sci U S A ; 120(11): e2216667120, 2023 03 14.
Article in English | MEDLINE | ID: mdl-36877838

ABSTRACT

Transmissible vaccines are an emerging biotechnology that hold prospects to eliminate pathogens from wildlife populations. Such vaccines would genetically modify naturally occurring, nonpathogenic viruses ("viral vectors") to express pathogen antigens while retaining their capacity to transmit. The epidemiology of candidate viral vectors within the target wildlife population has been notoriously challenging to resolve but underpins the selection of effective vectors prior to major investments in vaccine development. Here, we used spatiotemporally replicated deep sequencing to parameterize competing epidemiological mechanistic models of Desmodus rotundus betaherpesvirus (DrBHV), a proposed vector for a transmissible vaccine targeting vampire bat-transmitted rabies. Using 36 strain- and location-specific time series of prevalence collected over 6 y, we found that lifelong infections with cycles of latency and reactivation, combined with a high R0 (6.9; CI: 4.39 to 7.85), are necessary to explain patterns of DrBHV infection observed in wild bats. These epidemiological properties suggest that DrBHV may be suited to vector a lifelong, self-boosting, and transmissible vaccine. Simulations showed that inoculating a single bat with a DrBHV-vectored rabies vaccine could immunize >80% of a bat population, reducing the size, frequency, and duration of rabies outbreaks by 50 to 95%. Gradual loss of infectious vaccine from vaccinated individuals is expected but can be countered by inoculating larger but practically achievable proportions of bat populations. Parameterizing epidemiological models using accessible genomic data brings transmissible vaccines one step closer to implementation.


Subject(s)
Betaherpesvirinae , Chiroptera , Rabies Vaccines , Rabies , Humans , Animals , Rabies Vaccines/genetics , Rabies/epidemiology , Rabies/prevention & control , Rabies/veterinary , Vaccination/veterinary , Animals, Wild
7.
Infect Dis Poverty ; 12(1): 10, 2023 Feb 13.
Article in English | MEDLINE | ID: mdl-36782311

ABSTRACT

BACKGROUND: The term virus 'spillover' embodies a highly complex phenomenon and is often used to refer to viral transmission from a primary reservoir host to a new, naïve yet susceptible and permissive host species. Spillover transmission can result in a virus becoming pathogenic, causing disease and death to the new host if successful infection and transmission takes place. MAIN TEXT: The scientific literature across diverse disciplines has used the terms virus spillover, spillover transmission, cross-species transmission, and host shift almost indistinctly to imply the complex process of establishment of a virus from an original host (source/donor) to a naïve host (recipient), which have close or distant taxonomic or evolutionary ties. Spillover transmission may result in unsuccessful onward transmission, if the virus dies off before propagation. Alternatively, successful viral establishment in the new host can occur if subsequent secondary transmission among individuals of the same novel species and among other sympatric susceptible species occurred. As such, virus spillover transmission is a common yet highly complex phenomenon that encompasses multiple subtle stages that can be deconstructed to be studied separately to better understand the drivers of disease emergence. Rabies virus (RABV) is a well-documented viral pathogen which still inflicts heavy impact on humans, companion animals, wildlife, and livestock throughout Latin America due substantial spatial temporal and ecological-natural and expansional-overlap with several virus reservoir hosts. Thereby, the rabies disease system represents a robust avenue through which the drivers and uncertainties surrounding spillover transmission can be unravel at its different subtle stages to better understand how they may be affected by coarse, medium, and fine scale variables. CONCLUSIONS: The continued study of viral spillover transmission necessitates the elucidation of its complexities to better assess the cross-scale impacts of ecological forces linked to the propensity of spillover success. Improving capacities to reconstruct and predict spillover transmission would prevent public health impacts on those most at risk populations across the globe.


Subject(s)
Chiroptera , Rabies virus , Rabies , Animals , Humans , Rabies/epidemiology , Rabies/veterinary , Rabies/prevention & control , Livestock , Phylogeny
8.
J Med Entomol ; 60(1): 213-217, 2023 01 12.
Article in English | MEDLINE | ID: mdl-36269279

ABSTRACT

The bacterial genus Borrelia comprises vector-borne spirochetes that have been classified into three major groups: the relapsing fever group (RFG), the Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner sensu lato group (Bbsl), and the reptile-monotreme group (RMG). All three groups have been associated mainly with ticks and wild animals, especially rodents, birds, and reptiles. Here, we searched for Borrelia infection among 99 vampire bats [Desmodus rotundus (É. Geoffroy)] (Chiroptera: Phyllostomidae) from the Brazilian semiarid region. Through molecular investigation of bat internal organs, haplotypes of a potentially novel Borrelia organism were detected in 5% (5/99) of the bats. Borrelia DNA was detected in the liver, blood, spleen, kidney and brain, suggesting a systemic infection. Phylogenetic analyses inferred from partial sequences of the borrelial rrs and flaB genes indicated that the vampire bat-associated Borrelia sp. of this study form a monophyletic group with a newly reported Borrelia associated with a Colombia bat, distinct from the three main currently recognized groups of Borrelia spp., Bbsl, RFG, and RMG. These novel bat-associated Borrelia spp. from South America might have arisen through an independent event along the borrelial evolutionary history, since previous molecular reports of Borrelia organisms in bats or bat-associated ticks from Africa, Europe, and North America were all classified in the RFG.


Subject(s)
Argasidae , Borrelia , Chiroptera , Relapsing Fever , Animals , Argasidae/microbiology , Borrelia/genetics , Borrelia/isolation & purification , Brazil , Chiroptera/microbiology , Genotype , Phylogeny , Relapsing Fever/genetics , Relapsing Fever/microbiology , Evolution, Molecular
9.
Front Immunol ; 14: 1281732, 2023.
Article in English | MEDLINE | ID: mdl-38193073

ABSTRACT

Bats carry many zoonotic pathogens without showing pronounced pathology, with a few exceptions. The underlying immune tolerance mechanisms in bats remain poorly understood, although information-rich omics tools hold promise for identifying a wide range of immune markers and their relationship with infection. To evaluate the generality of immune responses to infection, we assessed the differences and similarities in serum proteomes of wild vampire bats (Desmodus rotundus) across infection status with five taxonomically distinct pathogens: bacteria (Bartonella spp., hemoplasmas), protozoa (Trypanosoma cruzi), and DNA (herpesviruses) and RNA (alphacoronaviruses) viruses. From 19 bats sampled in 2019 in Belize, we evaluated the up- and downregulated immune responses of infected versus uninfected individuals for each pathogen. Using a high-quality genome annotation for vampire bats, we identified 586 serum proteins but found no evidence for differential abundance nor differences in composition between infected and uninfected bats. However, using receiver operating characteristic curves, we identified four to 48 candidate biomarkers of infection depending on the pathogen, including seven overlapping biomarkers (DSG2, PCBP1, MGAM, APOA4, DPEP1, GOT1, and IGFALS). Enrichment analysis of these proteins revealed that our viral pathogens, but not the bacteria or protozoa studied, were associated with upregulation of extracellular and cytoplasmatic secretory vesicles (indicative of viral replication) and downregulation of complement activation and coagulation cascades. Additionally, herpesvirus infection elicited a downregulation of leukocyte-mediated immunity and defense response but an upregulation of an inflammatory and humoral immune response. In contrast to our two viral infections, we found downregulation of lipid and cholesterol homeostasis and metabolism with Bartonella spp. infection, of platelet-dense and secretory granules with hemoplasma infection, and of blood coagulation pathways with T. cruzi infection. Despite the small sample size, our results suggest that vampire bats have a similar suite of immune mechanisms for viruses distinct from responses to the other pathogen taxa, and we identify potential biomarkers that can expand our understanding of pathogenesis of these infections in bats. By applying a proteomic approach to a multi-pathogen system in wild animals, our study provides a distinct framework that could be expanded across bat species to increase our understanding of how bats tolerate pathogens.


Subject(s)
Chagas Disease , Chiroptera , Humans , Animals , Proteomics , Phenotype , Down-Regulation , Biomarkers
10.
Viruses ; 14(11)2022 10 22.
Article in English | MEDLINE | ID: mdl-36366416

ABSTRACT

Spatial expansions of vampire bat-transmitted rabies (VBR) are increasing the risk of lethal infections in livestock and humans in Latin America. Identifying the drivers of these expansions could improve current approaches to surveillance and prevention. We aimed to identify if VBR spatial expansions are occurring in Colombia and test factors associated with these expansions. We analyzed 2336 VBR outbreaks in livestock reported to the National Animal Health Agency (Instituto Colombiano Agropecuario-ICA) affecting 297 municipalities from 2000-2019. The area affected by VBR changed through time and was correlated to the reported number of outbreaks each year. Consistent with spatial expansions, some municipalities reported VBR outbreaks for the first time each year and nearly half of the estimated infected area in 2010-2019 did not report outbreaks in the previous decade. However, the number of newly infected municipalities decreased between 2000-2019, suggesting decelerating spatial expansions. Municipalities infected later had lower cattle populations and were located further from the local reporting offices of the ICA. Reducing the VBR burden in Colombia requires improving vaccination coverage in both endemic and newly infected areas while improving surveillance capacity in increasingly remote areas with lower cattle populations where rabies is emerging.


Subject(s)
Chiroptera , Rabies virus , Rabies , Animals , Cattle , Humans , Rabies/epidemiology , Rabies/prevention & control , Rabies/veterinary , Colombia/epidemiology , Livestock
11.
Proc Biol Sci ; 289(1982): 20220860, 2022 09 14.
Article in English | MEDLINE | ID: mdl-36069012

ABSTRACT

The pathogen transmission dynamics in bat reservoirs underpin efforts to reduce risks to human health and enhance bat conservation, but are notoriously challenging to resolve. For vampire bat rabies, the geographical scale of enzootic cycles, whether environmental factors modulate baseline risk, and how within-host processes affect population-level dynamics remain unresolved. We studied patterns of rabies exposure using an 11-year, spatially replicated sero-survey of 3709 Peruvian vampire bats and co-occurring outbreaks in livestock. Seroprevalence was correlated among nearby sites but fluctuated asynchronously at larger distances. A generalized additive mixed model confirmed spatially compartmentalized transmission cycles, but no effects of bat demography or environmental context on seroprevalence. Among 427 recaptured bats, we observed long-term survival following rabies exposure and antibody waning, supporting hypotheses that immunological mechanisms influence viral maintenance. Finally, seroprevalence in bats was only weakly correlated with outbreaks in livestock, reinforcing the challenge of spillover prediction even with extensive data. Together our results suggest that rabies maintenance requires transmission among multiple, nearby bat colonies which may be facilitated by waning of protective immunity. However, the likelihood of incursions and dynamics of transmission within bat colonies appear largely independent of bat ecology. The implications of these results for spillover anticipation and controlling transmission at the source are discussed.


Subject(s)
Chiroptera , Rabies virus , Rabies , Animals , Humans , Livestock , Rabies/epidemiology , Rabies/veterinary , Seroepidemiologic Studies
12.
Zoology (Jena) ; 150: 125980, 2022 02.
Article in English | MEDLINE | ID: mdl-34861535

ABSTRACT

Tissue changes during embryonic and postnatal development are critical for the success of physiological processes later in mammalian life. Dietary transition from milk to a variety of other food items is one of the factors inducing these changes in mammal species. Blood is utilized as food by only three species of vampire bats among all living mammals. Considering its high protein content, this unique diet is known to induce several metabolic changes, including fasting susceptibility. However, changes in the renal function to meet the excretory needs associated to the blood diet are unknown. Here we aimed at investigating morphological alterations in vampires' kidneys during embryonic and post-natal development in order to better understand the evolutionary adaptations allowing sanguivory. Common vampire bats (Desmodus rotundus) were captured and had their kidneys removed for histological, morphometrical and stereological analysis. Our results showed increased glomerular area and higher glomerular and uriniferous tubules volumetric densities in adults compared to developing bats. These results, together with a higher Renal Somatic Index and a thicker inner medulla also reported for adults, support renal hypertrophy due to increased renal function in blood-feeding vampires as compared to the earlier life stages. We also report a lower foot process density and its different arrange inside the glomerular capsule in adults, indicating an adaptation to a larger extracellular volume formed by increased glomerular filtration. Taken together, kidney morphological changes reported here for vampire bats may reflect in adults' adaptations to a monotrophic strategy.


Subject(s)
Chiroptera , Adaptation, Physiological , Animals , Biological Evolution , Diet , Kidney/physiology
13.
Transbound Emerg Dis ; 69(4): 2384-2389, 2022 Jul.
Article in English | MEDLINE | ID: mdl-33977671

ABSTRACT

The vampire bat (Desmodus rotundus) is a haematophagous animal that feeds exclusively on the blood of domestic mammals. Vampire bat feeding habits enable their contact with mammalian hosts and may enhance zoonotic spillover. Moreover, they may carry several pathogenic organisms, including coronaviruses (CoVs), for which they are important hosts. The human pathogens that cause severe acute respiratory syndrome (SARS-CoV), Middle East respiratory syndrome (MERS-CoV) and possibly coronavirus disease 2019 (SARS-CoV-2) all originated in bats but required bridge hosts to spread into human populations. To monitor the presence of potential zoonotic viruses in bats, the present work evaluated the presence of CoVs in vampire bats from southern Brazil. A total of 101 vampire bats were captured and euthanized between 2017 and 2019 in Rio Grande do Sul state, southern Brazil. The brain, heart, liver, lungs, kidneys and intestines were collected and macerated individually. The samples were pooled and submitted to high-throughput sequencing (HTS) using the Illumina MiSeq platform and subsequently individually screened using a pancoronavirus RT-PCR protocol. We detected CoV-related sequences in HTS, but only two (2/101; 1.98%) animals had CoV detected in the intestines by RT-PCR. Partial sequences of RdRp and spike genes were obtained in the same sample and the RdRp region in the other sample. The sequences were classified as belonging to Alphacoronavirus. The sequences were closely related to alphacoronaviruses detected in vampire bats from Peru. The continuous monitoring of bat CoVs may help to map and predict putative future zoonotic agents with great impacts on human health.


Subject(s)
Chiroptera , Coronaviridae , Animals , Brazil/epidemiology , Chiroptera/virology , Coronaviridae/classification , Coronaviridae/isolation & purification , Phylogeny , RNA-Dependent RNA Polymerase
14.
Acta Trop ; 225: 106206, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34687642

ABSTRACT

The protozoan Trypanosoma cruzi, the causative agent of Chagas disease, is transmitted by infected feces or consumption of blood-sucking triatomine insects to several mammalian orders including Chiroptera. In Chile, the distribution of several insectivorous and one hematophagous bat species overlaps with those of triatomine vectors, but the T. cruzi infection status of local chiropterans is unknown. In 2018, we live-captured bats from two protected areas in Chile to collect plagiopatagium tissue, feces and perianal swab samples, in search for T. cruzi-DNA by real time PCR assays using species-specific primers. In Pan de Azúcar island (∼26°S), we examined a roost of Desmodus rotundus (common vampire bat) and sampled tissue from 17 individuals, detecting T. cruzi-DNA in five of them. In Las Chinchillas National Reserve (∼31°S), we examined two roosts of Histiotus montanus (small big-eared brown bat), collecting feces or perianal swab samples from eight individuals, detecting T. cruzi-DNA in four of them. This is the first report of T. cruzi-DNA evidence in bat species from Chile. Both vector-borne and oral transmission are potential infection routes that can explain our results. Further investigation is needed for a better understanding of the role of bats in the T. cruzi transmission cycle.


Subject(s)
Chagas Disease , Chiroptera , Trypanosoma cruzi , Animals , Chagas Disease/veterinary , Chile , Humans , Mammals , Trypanosoma cruzi/genetics
15.
Trop Med Infect Dis ; 6(2)2021 Jun 09.
Article in English | MEDLINE | ID: mdl-34207822

ABSTRACT

Rabies is listed as one of the World Health Organisation's (WHO) Neglected Tropical Diseases Worldwide, with a significant impact in South America. This paper explores the dynamics of rabies cases in humans, pets (dogs and cats), livestock and wildlife (bats in particular) in South America during the period 2009-2018. The data used in this study were derived from the two main databases for rabies in South America: the OIE-WAHIS from the World Organisation for Animal Health (OIE) and PANAFTOSA's Regional Information System for the Epidemiological Surveillance of Rabies (SIRVERA). Being a neglected disease with possible underreporting in some areas, the reported rabies cases may not always represent the real disease burden. The analysis focuses on the evolution of the number of cases in time and their spatial distribution, as well as on the main source of infections in humans, determined by laboratory assays of the antigenic variant or through epidemiological investigations. Additionally, Generalised Linear Mixed Models (GLMM) were used to evaluate the risk factors associated with the occurrence of human cases. Our results show that the highest impact of the disease in terms of number of cases was reported on livestock, while the overall number of cases (in animals and humans) progressively decreased along the study period. The spatial distribution of rabies in livestock showed two main clusters in the north-western (mainly Colombia) and in the south-eastern part of the affected area (Brazil), and a third smaller cluster in Peru. A cluster in dogs was observed in Bolivia. Out of the 192 human cases reported during the study period, 70% of them were transmitted by bats. The number of human cases reported during the study period were significantly associated with the number of rabies cases reported in livestock, pets and wildlife. Despite the overall decreasing case report rate, the disease still represents a major animal and public health concern in South America, and new strategies for compiling systematic information, networking and education are needed, as well as the education and training of veterinary staff.

16.
Zoonoses Public Health ; 68(3): 271-276, 2021 05.
Article in English | MEDLINE | ID: mdl-33484236

ABSTRACT

Trypanosoma cruzi is widely reported in bats, yet transmission routes remain unclear. We present evidence from metagenomic sequence data that T. cruzi occurs in the saliva of diverse Neotropical bats. Phylogenetic analyses demonstrated that the bat-associated T. cruzi sequences described here formed part of a bat-specific clade, suggesting an independent transmission cycle. Our results highlight the value in repurposing metagenomic data generated for viral discovery to reveal insights into the biology of other parasites. Evaluating whether the presence of T. cruzi in the saliva of two hematophagous bat species represents an ecological route for zoonotic transmission of Chagas disease is an interesting avenue for future research.


Subject(s)
Chiroptera/virology , Saliva/virology , Trypanosoma cruzi/isolation & purification , Animals , Peru , Phylogeny , Trypanosoma cruzi/genetics
17.
Transbound Emerg Dis ; 68(3): 1564-1576, 2021 May.
Article in English | MEDLINE | ID: mdl-32931658

ABSTRACT

Serology is a core component of the surveillance and management of viral zoonoses. Virus neutralization tests are a gold standard serological diagnostic, but requirements for large volumes of serum and high biosafety containment can limit widespread use. Here, focusing on Rabies lyssavirus, a globally important zoonosis, we developed a pseudotype micro-neutralization rapid fluorescent focus inhibition test (pmRFFIT) that overcomes these limitations. Specifically, we adapted an existing micro-neutralization test to use a green fluorescent protein-tagged murine leukaemia virus pseudotype in lieu of pathogenic rabies virus, reducing the need for specialized reagents for antigen detection and enabling use in low-containment laboratories. We further used statistical models to generate rapid, quantitative predictions of the probability and titre of rabies virus-neutralizing antibodies from microscopic imaging of neutralization outcomes. Using 47 serum samples from domestic dogs with neutralizing antibody titres estimated using the fluorescent antibody virus neutralization test (FAVN), pmRFFIT showed moderate sensitivity (78.79%) and high specificity (84.62%). Despite small conflicts, titre predictions were correlated across tests repeated on different dates both for dog samples (r = 0.93) and in a second data set of sera from wild common vampire bats (r = 0.72, N = 41), indicating repeatability. Our test uses a starting volume of 3.5 µl of serum, estimates titres from a single dilution of serum rather than requiring multiple dilutions and end point titration, and may be adapted to target neutralizing antibodies against alternative lyssavirus species. The pmRFFIT enables high-throughput detection of rabies virus-neutralizing antibodies in low-biocontainment settings and is suited to studies in wild or captive animals where large serum volumes cannot be obtained.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Dog Diseases/blood , Neutralization Tests/veterinary , Rabies virus/isolation & purification , Rabies/veterinary , Animals , Dogs , Green Fluorescent Proteins/chemistry , Neutralization Tests/instrumentation , Rabies/blood
18.
Zoology (Jena) ; 144: 125861, 2021 02.
Article in English | MEDLINE | ID: mdl-33232886

ABSTRACT

Bats have adapted to many different feeding habits, which are known to induce morphophysiological adaptations in several tissues, especially those particularly involved with absorption, metabolism and excretion. The common vampire bat (Desmodus rotundus) has a very unique diet (blood), which, among other challenges, seems to pose a risk to their kidneys, due to the increased nitrogen excretion imposed by their remarkably high protein meal. Fruit-eating bats (Artibeus lituratus) consume a high carbohydrate diet and may be taken as a suitable species for this dietary comparative study. Here we aimed at investigating the renal morphology and stereology, kidneys antioxidant capacity, and plasma antidiuretic hormone (ADH) concentrations in adult fruit-eating and vampire bats. Sixteen animals were captured and used in this study, being 8 adult males from each species. Our results showed higher morphological standards of glomerular area, volumetric density of glomeruli, and renal somatic index for vampire bats, as well as higher reactive species of oxygen (ROS) production, such as nitric oxide (NO), higher plasma iron reduction ability (FRAP), higher activity of the antioxidant enzyme glutathione-S-transferase (GST) and a higher malondialdehyde production (MDA) in vampires' kidneys, compared to the fruit-eating species. The activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) were higher in fruit-eating bats. Plasma ADH concentrations were not different between species. Taken together, the renal morphophysiology conditions presented by vampire bats might be associated with a high demand for nitrogenous products excretion imposed by protein and iron overload. These features may play an important role on preventing protein-overload nephropathy, allowing vampires to survive under such a unique diet.


Subject(s)
Chiroptera/anatomy & histology , Chiroptera/classification , Feeding Behavior , Kidney/anatomy & histology , Kidney/physiology , Adaptation, Physiological , Animals , Blood , Chiroptera/physiology , Diet/veterinary , Fruit , Male
19.
Braz. J. Vet. Res. Anim. Sci. (Online) ; 58: e183270, 2021. mapas, graf, ilus, tab
Article in English | LILACS, VETINDEX | ID: biblio-1344760

ABSTRACT

Livestock rabies is endemic in Peru. Hence, its persistence and annual dissemination represent an important economic impact, especially for impoverished farming communities. The disease is mostly transmitted by the hematophagous bat Desmodus rotundus. The present study aimed to adapt an existing predictive model of the occurrence of livestock rabies to Peru, in which the risk of rabies transmission from bats to livestock was estimated using decision-tree models of receptivity and vulnerability. Official rabies surveillance data between 2010 and 2015 were used along with possible risk factors, such as livestock biomass, environmental changes, and geomorphological characteristics. Several scenarios were established to evaluate the prediction of the occurrence of livestock rabies cases by determining more than one cut-off point of the receptivity variables. During the study period, the precision of the model was estimated through the sensitivity (39.46%) and specificity (98.64%) by using confusion matrices. Targeting control efforts, especially in districts with a high estimated risk, could represent the prevention of a significant proportion of livestock rabies cases, which would optimize the human and economic resources of the Peruvian surveillance service. However, the quality of data produced by the surveillance should be improved not only to obtain higher model precision but also to allow the adequate planning of control actions.(AU)


Raiva de herbívoros é endêmica no Peru. Consequentemente, sua disseminação persistente e anual representa um importante impacto econômico, especialmente às comunidades rurais empobrecidas. A doença é principalmente transmitida pelo morcego hematófago Desmodus rotundus. Este estudo tem por objetivo adaptar um modelo preditivo pré-existente às ocorrências de raiva de herbívoros no Peru, no qual o risco de transmissão de morcegos para os herbívoros foi estimado por meio de árvores de cenários de receptividade e vulnerabilidade. Foram usados os dados oficiais de vigilância da raiva entre 2010 e 2015, assim como os possíveis fatores de risco, tais quais a biomassa de animais, alterações ambientais e características geomorfológicas. Diversos cenários foram criados para avaliar a predição da ocorrência da raiva por meio da determinação de diversos pontos de corte das variáveis de receptividade. Durante o período de estudo, a precisão do modelo foi estimada por meio da sensibilidade (39,46%) e especificidade (98,64%), utilizando matrizes de confusão. Focando em esforços de controle, especialmente em distritos com elevado risco estimado, seria possível prevenir uma proporção significativa dos focos, o que poderia otimizar os recursos humanos e econômicos do serviço oficial peruano. Entretanto, a qualidade dos dados produzidos pelo sistema de vigilância deveria ser melhorada não somente para obter maior precisão do modelo, mas também para possibilitar o melhor planejamento das ações de controle desta doença.(AU)


Subject(s)
Animals , Rabies virus , Proportional Hazards Models , Chiroptera/virology , Infections/diagnosis
20.
Entomol Commun, v. 3, ec03046, dez. 2021
Article in English | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-4773

ABSTRACT

Macronyssid mites are ectoparasites of reptiles, birds, and mammals (mainly bats). Out of 35 genera in this family, Radfordiella Fonseca, 1948 is a genus from the Neotropical region with six valid species, found parasitizing phyllostomid bats. Only Radfordiella desmodi Radovsky, 1967 and Radfordiella oudemansi Fonseca, 1948 have been registered in Brazil. The present study provides a new locality record for the species R. desmodi, microscopy images to aid in the identification, and a distribution map.

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