La coexistencia de Desmodus rotundus con la población humana en San Luis Potosí, México

Desmodus rotundus es transmisor de enfermedades zoonóticas y emergentes a los humanos y al ganado, como el caso de la rabia. La mayoría de las enfermedades infecciosas están limitadas espacialmente por la presencia del transmisor, cuya abundancia y supervivencia son influenciadas por las condiciones ambientales y la presencia de fuentes de alimentación. Una herramienta que facilita su estudio es el uso de los Sistemas de Información Geográfica. El objetivo de este estudio fue analizar la interacción de las poblaciones de murciélagos hematófagos y humanos, a través de la elaboración de un modelo probable de dispersión del D. rotundus basado en refugios conocidos y diferentes variables medioambientales, además de analizar la relación entre refugios identificados durante tres años y su cercanía con asentamientos humanos, como un proceso de coexistencia. El estudio se llevó a cabo en el estado de San Luis Potosí del año 2014 al 2016. Se identificaron un total de 180 refugios de D. rotundus distribuidos hacia la zona de la Huasteca, el 80 % de éstos fueron construidos por el hombre y el 57 % se encontraron habitados. Se calculó un buffer de 5 km a la redonda a partir de la ubicación de cada refugio, encontrando en su interior un total de 976 comunidades rurales y 15 ciudades, con 337,836 habitantes. La distancia media de los refugios hasta el primer asentamiento humano fue de 518.65 ± 11.33 m. Es necesario continuar estudiando la asociación entre la urbanización y el surgimiento de zoonosis, a través del entendimiento de las interacciones entre animales silvestres-ganadería - humanos.

OCORRÊNCIA DO VÍRUS DA RAIVA NA POPULAÇÃO SELVAGEM DE SAGUIS CALLITHRIX GEOFFROYI (HUMBOLDT, 1812) NO SUDESTE DO BRASIL

Background: Zoonosis, which causes acute and lethal encephalitis, is transmitted through the inoculation of the virus present in the saliva of mammals of several species. In Brazil, wild rabies is a challenge for epidemiological surveillance and a significant increase has already been observed in human cases. Some of the main wild reservoirs are: wild dog (Cerdocyon thous), marmosets (Callithrix sp) and hematophagous bats (Desmodus rotundus). Considering cases of positivity in marmosets in the Northeast of Brazil, together with the increasing number of cases in wild animals, this work aimed to survey the occurrence of the virus in a wild population. The animals were necropsied from the tramway ES-060, all of the Callithrix geoffroyi. The material collected for analysis of the rabies virus consisted of brain, which was conditioned and identified for later analysis at the Institute of Agricultural and Forest Defense of Espírito Santo (IDAF). The 44 samples gave negative results. The study suggests that the occurrence of the virus should be investigated in other localities, especially in regions closer to sites that have already been reported cases of rabies, and that the use of trampled animals is feasible for a better understanding of wildlife health.

A two-step metagenomics approach for prey identification from the blood meals of common vampire bats (Desmodus rotundus)

ABSTRACTThe feeding behaviour of the sanguivorous common vampire bat (Desmodus rotundus) facilitates the transmission of pathogens that can impact both human and animal health. To formulate effective strategies in controlling the spread of diseases, there is a need to obtain information on which animals they feed on. One DNA-based approach, shotgun sequencing, can be used to obtain such information. Even though it is costly, shotgun sequencing can be used to simultaneously retrieve prey and vampire bat mitochondrial DNA for population studies within one round of sequencing. However, due to the challenges of analysing shotgun sequenced metagenomic data such as false negatives/positives and typically low proportion of reads mapped to diet items, shotgun sequencing has not been used for the identification of prey from common vampire bat blood meals. To overcome these challenges and generate longer mitochondrial contigs which could be useful for prey population studies, we shotgun sequenced common vampire bat blood meal samples (n=8) and utilised a two-step metagenomic approach based on combining existing bioinformatic workflows (alignment and de novo mtDNA assembly) to identify prey. Further, we validated our results to detections made through metabarcoding. We accurately identified the common vampire bats’ prey in seven out of eight samples without any false positives. We also generated prey mitochondrial contig lengths between 138bp to 3231bp (mean=985bp, SD=981bp). As we develop more computationally efficient bioinformatics pipelines and reduce sequencing costs, we can expect an uptake in metagenomics dietary studies in the near future.

Habituation of common vampire bats to biologgers

Rapid advancements in biologging technology have led to unprecedented insights into animal behaviour, but testing the effects of biologgers on tagged animals is necessary for both scientific and ethical reasons. Here, we measured how quickly 13 wild-caught and captively isolated common vampire bats ( Desmodus rotundus ) habituated to mock proximity sensors glued to their dorsal fur. To assess habituation, we scored video-recorded behaviours every minute from 18.00 to 06.00 for 3 days, then compared the rates of grooming directed to the sensor tag versus to their own body. During the first hour, the mean tag-grooming rate declined dramatically from 53% of sampled time (95% CI = 36–65%, n = 6) to 16% (8–24%, n = 9), and down to 4% by hour 5 (1–6%, n = 13), while grooming of the bat's own body did not decline. When tags are firmly attached, isolated individual vampire bats mostly habituate within an hour of tag attachment. In two cases, however, tags became loose before falling off causing the bats to dishabituate. For tags glued to fur, behavioural data are likely to be impacted immediately after the tag is attached and when it is loose before it falls off.

Potential attack of the common vampire bat (Desmodus rotundus) on nine-banded armadillo (Dasypus novemcinctus) in northern Oaxaca, México

El murciélago vampiro común, Desmodus rotundus, es un depredador que de forma obligatoria, se alimenta de sangre de vertebrados de un grupo diverso de presas, pero con preferencia a los mamíferos, tanto nativos como exóticos. El presente registro documenta la primera depredación potencial de un armadillo de nueve bandas, Dasypus novemcinctus, por D. rotundus en vida silvestre. La observación se registró en una cámara trampa colocada en un fragmento de crecimiento secundario de un bosque tropical perennifolio en Oaxaca, México. En una grabación de 10 segundos, observamos a un individuo de D. rotundus acechando y persiguiendo a un individuo de D. novemcinctus que busca alimento en la hojarasca. La presente observación, junto con otro estudio realizado en Brasil, donde un murciélago vampiro persiguió a un armadillo gigante Priodontes maximus, sugiere que los armadillos podrían ser presas de D. rotundus, pero la interacción es difícil de registrar en vida silvestre.

Análise quantitativa de fatores de receptividade ligados à presença de abrigos de morcegos (Desmodus rotundus) na região centro leste do estado de São Paulo

Durante os anos de 2002 a 2004 foi realizado estudo na região centro leste do estado de São Paulo, com objetivo de analisar quantitativamente determinantes de receptividade à presença de abrigos de morcegos hematófagos Desmodus rotundus (E. Geoffroy, 1810, Chiroptera, Phyllostomidae) utilizando de Sistema de Informações Geográficas (SIG). Foram encontrados 1.566 D. rotundus distribuídos em 93 abrigos em 18 municípios. Em relação à topografia, a maioria dos abrigos artificiais estavam localizados em áreas de baixas declividades e em cotas altimétricas inferiores a 712 m, porém a maioria dos abrigos naturais estavam localizados em cotas altimétricas entre 712 - 812 m podendo ser um indício de altitudes preferenciais à colonização de D. rotundus para esse tipo de abrigo. Em relação à cobertura e ao uso do solo, a maioria dos abrigos estavam em área de agricultura e nenhum abrigo natural foi encontrado em áreas de formação florestal, indicando alto grau de antropização do meio rural e florestal da região, com aumento da oferta de abrigos artificiais para D. rotundus em relação aos abrigos naturais. A quantificação dos fatores de receptividade relacionados à topografia e ao tipo e cobertura do solo podem auxiliar na elaboração de modelos de áreas de risco de ataques de morcegos hematófagos a herbívoros domésticos, devendo-se levar em consideração os efeitos de escala de cada trabalho e as características de paisagem da região estudada.

Captura e identificação de diaemus youngi e diphyla ecaudata em São Francisco do Guaporé, Rondônia

<p>Os morcegos hematófagos são da subfamília <em>Desmodontinae</em>, restrita ao continente americano, e é composta por três espécies hematófagas: <em>Desmodus rotundus, Diphylla ecaudata</em> e <em>Diaemus youngi</em>. As capturas de morcegos hematófagos, e o tratamento do <em>Desmodus rotundus</em>, são ações rotineiras da Agência IDARON na aplicação do Plano Nacional de Controle de Raiva em Herbívoros – PNCRH, onde o objetivo principal do programa é manter sob controle a incidência da raiva na população de herbívoros domésticos. Os morcegos saem para forragear a noite, e por conta disso, é o período principal para realizar as capturas. A equipe da Agência IDARON ULSAV São Francisco do Guaporé/RO, realizou duas atividades de captura de morcegos nos dias 02 e 09 de junho de 2021, em propriedades com queixas de ataque em aves e bovinos, e onde foi realizada a coleta de encéfalo por conta de suspeita de raiva herbívora. Nas respectivas capturas, foram identificados os morcegos <em>Diaemus youngi</em> e <em>Diphylla ecaudata</em>, nessa mesma ordem. Mesmo tendo sido o primeiro relato científico das espécies na região, o banco de dados da agência IDARON relata que entre 2017 e 2019 houve 16 capturas de <em>Diaemus youngi</em>, e a primeira de <em>Diphylla ecaudata</em>, o que demonstra a importância e necessidade de publicação de dados coletados na rotina da agência.</p>

Serological Surveillance of Rabies in Free-Range and Captive Common Vampire Bats Desmodus rotundus

The control of vampire bat rabies (VBR) in Brazil is based on the culling of Desmodus rotundus and the surveillance of outbreaks caused by D. rotundus in cattle and humans in addition to vaccination of susceptible livestock. The detection of anti-rabies antibodies in vampire bats indicates exposure to the rabies virus, and several studies have reported an increase of these antibodies following experimental infection. However, the dynamics of anti-rabies antibodies in natural populations of D. rotundus remains poorly understood. In this study, we took advantage of recent outbreaks of VBR among livestock in the Sao Paulo region of Brazil to test whether seroprevalence in D. rotundus reflects the incidence of rabies in nearby livestock populations. Sixty-four D. rotundus were captured during and after outbreaks from roost located in municipalities belonging to three regions with different incidences of rabies in herbivores. Sixteen seropositive bats were then kept in captivity for up to 120 days, and their antibodies and virus levels were quantified at different time points using the rapid fluorescent focus inhibition test (RFFIT). Antibody titers were associated with the occurrence of ongoing outbreak, with a higher proportion of bats showing titer &gt;0.5 IU/ml in the region with a recent outbreak. However, low titers were still detected in bats from regions reporting the last outbreak of rabies at least 3 years prior to sampling. This study suggests that serological surveillance of rabies in vampire bats can be used as a tool to evaluate risk of outbreaks in at risk populations of cattle and human.

VAMPIRE BAT DESMODUS ROTUNDUS SHELTERS IN THE CENTRAL REGION OF SÃO PAULO STATE, BRAZIL

The vampire bat Desmodus rotundus is the main transmitter of domestic herbivorous rabies, which causes economic losses in cattle raising, being a serious public health problem. The use of Geographic Information Systems (GIS) allows the spatial monitoring of these bats shelters, which is an efficient way to prevent and control rabies. This study located shelters of D. rotundus in the Eastern Center region of São Paulo state and identified the types of shelters used (natural or artificial), their proximity to water, sexual composition, and population estimated of the colonies. Searches were carried out by colonies of vampire bats in natural and artificial shelters during 2002 to 2004, covering 18 municipalities. After located, the shelters were georeferenced, being recorded the nature of the shelter (natural or artificial), use (shelters of males, maternities, digestive) and estimated population. The data were incorporated into a GIS, producing a thematic map of the shelter’s location and their distance from the local water bodies. There were found 1.567 D. rotundus distributed in 94 shelters, where only six shelters (6.38%) were natural (caves). Most shelters (79.78%) were sparsely populated, with up to 15 bats, including male shelters (46 shelters) and 30 maternities (63.82% of maternities). Five shelters (5.37%) had between 50 and 100 bats and only two shelters (2.15%) had a population greater than 100 bats. Six shelters (6.38%) were inhabited houses, which is a concern for public health, as these may constitute a source of dangerous contamination for domestic and human carnivores. All the shelters were at a distance of up to 2 km of rivers or streams. The high percentage of artificial shelters found is a consequence of the intensification of the anthropic changes that increase the supply of food and shelter to D. rotundus, which associated with a large drainage network favors the dispersion of this species of bat in the region. The proximity of all D. rotundus shelters to the drainage network corroborates other studies in São Paulo state, where the areas close to the main rivers generally favor the existence of a larger number of shelters.