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 >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.

Defining New Pathways to Manage the Ongoing Emergence of Bat Rabies in Latin America.

Rabies transmitted by common vampire bats (Desmodus rotundus) has been known since the early 1900s but continues to expand geographically and in the range of species and environments affected. In this review, we present current knowledge of the epidemiology and management of rabies in D. rotundus and argue that it can be reasonably considered an emerging public health threat. We identify knowledge gaps related to the landscape determinants of the bat reservoir, reduction in bites on humans and livestock, and social barriers to prevention. We discuss how new technologies including autonomously-spreading vaccines and reproductive suppressants targeting bats might manage both rabies and undesirable growth of D. rotundus populations. Finally, we highlight widespread under-reporting of human and animal mortality and the scarcity of studies that quantify the efficacy of control measures such as bat culling. Collaborations between researchers and managers will be crucial to implement the next generation of rabies management in Latin America.

Rabies virus monitoring in bat populations in Rondônia state, Brazil.

INTRODUCTION: The Jirau hydroelectric power plant built in Rondônia state has environmental impacts that could be relevant to rabies outbreaks. METHODS: Bat populations were monitored for rabies by fluorescent antibody testing and simplified fluorescent inhibition microtesting between 2010 and 2015. RESULTS: All 1,183 bats tested negative for rabies. The prevalence of rabies antibodies was 17.5% in 1,049 bats. CONCLUSIONS: The rabies antibody dosage was not reactive in samples collected before the environmental changes, and there was a progressive increase in subsequent collections that could indicate an increase in rabies virus circulation among bats and risk of a rabies outbreak.

Rabies virus monitoring in bat populations in Rondônia state, Brazil

Abstract INTRODUCTION: The Jirau hydroelectric power plant built in Rondônia state has environmental impacts that could be relevant to rabies outbreaks. METHODS: Bat populations were monitored for rabies by fluorescent antibody testing and simplified fluorescent inhibition microtesting between 2010 and 2015. RESULTS: All 1,183 bats tested negative for rabies. The prevalence of rabies antibodies was 17.5% in 1,049 bats. CONCLUSIONS: The rabies antibody dosage was not reactive in samples collected before the environmental changes, and there was a progressive increase in subsequent collections that could indicate an increase in rabies virus circulation among bats and risk of a rabies outbreak.

Hematologic profile of hematophagous Desmodus rotundus bats before and after experimental infection with rabies virus.

INTRODUCTION: Hematophagous Desmodus rotundus bats play an important role in the rabies lifecycle. This study describes the hematological profile of these bats before and after experimental infection with rabies virus. METHODS: Cells counts were performed in a Neubauer chamber. RESULTS: The average values of erythrocytes and leucocytes counts in blood before experimental infections were 9.97 × 10(6)mm3 and 4.80 × 10(3)mm3, respectively. Neutrophils represented 69.9% of white blood cells and the lymphocytes represented 26.9%. Following the experimental infections, the average numbers of erythrocytes and leucocytes was 9.43 × 106mm3 and 3.98 × 10(3)mm3, respectively. Neutrophils represented 40% of white blood cells and the lymphocytes represented 59%. CONCLUSIONS: The hematological profile given in this study can serve as reference values for D. rotundus bats.

Experimental infection of the bat tick Carios fonsecai (Acari: Ixodidae) with the rabies virus.

INTRODUCTION: This study assessed the viability of the rabies virus in the argasid tick Carios fonsecai following experimental infection. METHODS: The mouse inoculation test (MIT), fluorescent antibody test (FAT) and polymerase chain reaction (PCR) were used. The rabies virus was administered to ticks via the intra-coelomic route, and the ticks were sacrificed at different time points. RESULTS: The inoculated ticks were negative for rabies according to the MIT. Ticks macerated with rabies virus were positive according to the MIT and FAT. All of the tick lots tested by PCR were positive. CONCLUSIONS The rabies virus became unviable shortly after its inoculation into tick bodies. Ticks are not likely to play an important role in the epidemiology of rabies.

Rabies diagnosis and serology in bats from the State of São Paulo, Brazil.

INTRODUCTION: Bats are one of the most important reservoirs and vectors of the rabies virus in the world. METHODS: From 1988 to 2003, the Zoonosis Control Center in São Paulo City performed rabies diagnosis on 5,670 bats by direct immunofluorescent test and mouse inoculation test. Blood samples were collected from 1,618 bats and the sera were analyzed using the rapid fluorescent focus inhibition test to confirm rabies antibodies. RESULTS: Forty-four (0.8%) bats were positive for rabies. The prevalence of rabies antibodies was 5.9% using 0.5IU/ml as a cutoff. Insectivorous bats (69.8%) and bats of the species Molossus molossus (51.8%) constituted the majority of the sample; however, the highest prevalence of antibodies were observed in Glossophaga soricina (14/133), Histiotus velatus (16/60), Desmodus rotundus (8/66), Artibeus lituratus (5/54), Nyctinomops macrotis (3/23), Tadarida brasiliensis (3/48), Carollia perspicillata (3/9), Eumops auripendulus (2/30), Nyctinomops laticaudatus (2/16), Sturnira lilium (2/17) and Eumops perotis (1/13). The prevalence of rabies antibodies was analyzed by species, food preference and sex. CONCLUSIONS: The expressive levels of antibodies associated with the low virus positivity verified in these bats indicate that rabies virus circulates actively among them.

Rabies diagnosis and serology in bats from the State of São Paulo, Brazil / Diagnóstico e sorologia de raiva em morcegos do Estado de São Paulo, Brasil

INTRODUCTION: Bats are one of the most important reservoirs and vectors of the rabies virus in the world. METHODS: From 1988 to 2003, the Zoonosis Control Center in São Paulo City performed rabies diagnosis on 5,670 bats by direct immunofluorescent test and mouse inoculation test. Blood samples were collected from 1,618 bats and the sera were analyzed using the rapid fluorescent focus inhibition test to confirm rabies antibodies. RESULTS: Forty-four (0.8 percent) bats were positive for rabies. The prevalence of rabies antibodies was 5.9 percent using 0.5IU/ml as a cutoff. Insectivorous bats (69.8 percent) and bats of the species Molossus molossus (51.8 percent) constituted the majority of the sample; however, the highest prevalence of antibodies were observed in Glossophaga soricina (14/133), Histiotus velatus (16/60), Desmodus rotundus (8/66), Artibeus lituratus (5/54), Nyctinomops macrotis (3/23), Tadarida brasiliensis (3/48), Carollia perspicillata (3/9), Eumops auripendulus (2/30), Nyctinomops laticaudatus (2/16), Sturnira lilium (2/17) and Eumops perotis (1/13). The prevalence of rabies antibodies was analyzed by species, food preference and sex. CONCLUSIONS: The expressive levels of antibodies associated with the low virus positivity verified in these bats indicate that rabies virus circulates actively among them.

INTRODUÇÃO: Morcegos são um dos mais importantes reservatórios e vetores do vírus da raiva no mundo. MÉTODOS: No período entre 1998 e 2003, o Centro de Controle de Zoonoses da Cidade de São Paulo realizou o diagnóstico de raiva em 5.670 morcegos utilizando as técnicas de imunofluorescência direta e inoculação intracerebral em camundongos. Sangue foi coletado de 1.618 espécimes para pesquisa de anticorpos pela técnica de inibição de foco de fluorescência rápida. RESULTADOS: Quarenta e quatro (0,8 por cento) morcegos foram positivos para raiva. A prevalência de anticorpos foi de 5,9 por cento usando 0,5UI/ml como ponto de corte. Os morcegos de hábito alimentar insetívoro (69,8 por cento) e os morcegos da espécie Molossus molossus (51,8 por cento) representaram a maioria da amostra. Entretanto, as mais altas prevalências de anticorpos foram observadas nos morcegos Glossophaga soricina (14/133), Histiotus velatus (16/60), Desmodus rotundus (8/66), Artibeus lituratus (5/54), Nyctinomops macrotis (3/23), Tadarida brasiliensis (3/48), Carollia perspicillata (3/9), Eumops auripendulus (2/30), Nyctinomops laticaudatus (2/16), Sturnira lilium (2/17) e Eumops perotis (1/13). A prevalência de anticorpos foi analisada por espécie, hábito alimentar e sexo. CONCLUSÕES: O expressivo nível de anticorpos associado à baixa positividade para o vírus da raiva entre os morcegos estudados indica que o vírus circula ativamente entre morcegos.

Characterization of rabies virus isolated from a colony of Eptesicus furinalis bats in Brazil.

Some bat species have adapted to the expanding human population by acquiring the ability to roost in urban buildings, increasing the exposure risk for people and domestic animals, and consequently, the likelihood of transmitting rabies. Three dead bats were found in the yard of a house in an urban area of Jundiaí city in the state of São Paulo in southeast Brazil. Two of the three bats tested positive for rabies, using Fluorescent Antibody and Mouse Inoculation techniques. A large colony of Eptesicus furinalis was found in the house's attic, and of the 119 bats captured, four more tested positive for rabies. The objectives of this study were to report the rabies diagnosis, characterize the isolated virus antigenically and genetically, and study the epidemiology of the colony.

Characterization of rabies virus isolated from a colony of Eptesicus furinalis bats in Brazil / Caracterização do vírus da raiva isolado de uma colônia de morcegos Eptesicus furinalis, do Brasil

Some bat species have adapted to the expanding human population by acquiring the ability to roost in urban buildings, increasing the exposure risk for people and domestic animals, and consequently, the likelihood of transmitting rabies. Three dead bats were found in the yard of a house in an urban area of Jundiaí city in the state of São Paulo in southeast Brazil. Two of the three bats tested positive for rabies, using Fluorescent Antibody and Mouse Inoculation techniques. A large colony of Eptesicus furinalis was found in the house's attic, and of the 119 bats captured, four more tested positive for rabies. The objectives of this study were to report the rabies diagnosis, characterize the isolated virus antigenically and genetically, and study the epidemiology of the colony.

Algumas espécies de morcegos têm se adaptado ao uso de abrigos em construções urbanas, aumentando a possibilidade de contato desses morcegos com pessoas e animais domésticos e conseqüentemente, o potencial risco de transmissão de raiva. Três morcegos foram encontrados no jardim de uma casa na área urbana da cidade de Jundiaí, Estado de São Paulo, Sudeste do Brasil, dois deles foram positivos para raiva pelas técnicas de imunofluorescência e inoculação em camundongos. Uma grande colônia de E. furinalis foi identificada, vivendo no sótão da casa e 119 morcegos foram encaminhados para diagnóstico de raiva, com mais quatro morcegos positivos. O objetivo desse estudo é apresentar a caracterização genética e antigênica do vírus da raiva isolado desses morcegos e o estudo epidemiológico da colônia.

Serologic Survey for Rickettsiosis in Bats from São Paulo City, Brazil / Levantamento sorológico para rickettsioses em morcegos de São Paulo, Brasil

Blood serum samples were collected from 451 bats captured within the São Paulo city from April 2007 to November 2008, and individually tested by indirect immunofluorescence assay against antigens derived from five Rickettsia species reported to occur in Brazil: the spotted fever group (SFG) species R. rickettsii, R. parkeri, R. amblyommii, R. rhipicephali, and the ancestral group species R. bellii. For this purpose, an anti-bat immunoglobulin G was produced and used in the present study. Overall, 8.6% (39/451), 9.5% (34/358), 7.8% (28/358), 1.1% (4/358), and 0% (0/358) serum samples were reactive to R. rickettsii, R. parkeri, R. amblyommii, R. rhipicephali, and R. bellii, respectively. Endpoint titers of reactive sera ranged from 64 to 256. From 20 bat species of 3 different families (Molossidae, Vespertilionidae, and Phyllostomidae), 46 animals were shown to be reactive to at least one rickettsial antigen. Seropositivity per bat species ranged from 0% to 33.3%. Most of the serologically positive sera reacted with two or more rickettsial antigens. Seropositivity for SFG rickettsial antigens in the absence of reactivity against R. bellii (ancestral group species) suggests that bats from São Paulo city can be infected by SFG rickettsiae. The possible role of soft ticks in serving as vectors of SFG rickettsiae to bats within the São Paulo city, associated to its public health risks, is discussed.