Rabies Outbreaks Research Articles

Phylogenetic Comparison of Rabies Viruses from Disease Outbreaks on the Svalbard Islands

Periodic wildlife rabies epizootics occur in Arctic regions. The original sources of these outbreaks are rarely identified. In 1980, a wildlife epizootic of rabies occurred on the previously rabies-free Svalbard Islands, Norway. After this outbreak of rabies in the arctic fox population (Alopex lagopus), only single cases have been reported from the Islands over the following two decades. Phylogenetic characterization of four viruses isolated from infected arctic foxes from Svalbard from three different time periods suggest that the source of these epizootics could have been migration of this species from the Russian mainland. Arctic fox migration has likely contributed to the establishment of another zoonotic disease, Echinococcus multilocularis, on Svalbard in recent years.

An outbreak of pig rabies in Hunan province, China

The first dog-associated outbreak of rabies in swine in China (Hunan province) has been diagnosed and the related virus isolated. Sequence analysis showed that the pig isolate was a genotype 1 rabies virus with a very high nucleotide identity to local dog isolates.

The Conservation Relevance of Epidemiological Research into Carnivore Viral Diseases in the Serengeti

Recent outbreaks of rabies and canine distemper in wildlife populations of the Serengeti show that infectious disease constitutes a significant cause of mortality that can result in regional extirpation of endangered species even within large, well-protected areas. Nevertheless, effective management of an infectious disease depends critically on understanding the epidemiological dynamics of the causative pathogen. Pathogens with short infection cycles cannot persist in small populations in the absence of a more permanent reservoir of infection. Development of appropriate interventions requires detailed data on transmission pathways between reservoirs and wildlife populations of conservation concern. Relevant data can be derived from long-term population monitoring, epidemic and case-surveillance patterns, genetic analyses of rapidly evolving pathogens, serological surveys, and intervention studies. We examined studies of carnivore diseases in the Serengeti. Epidemiological research contributes to wildlife conservation policy in terms of management of endangered populations and the integration of wildlife conservation with public health interventions. Long-term, integrative, cross-species research is essential for formulation of effective policy for disease control and optimization of ecosystem health.

THE ELIMINATION OF RACCOON RABIES FROM WOLFE ISLAND, ONTARIO: ANIMAL DENSITY AND MOVEMENTS

During 1996 to 1998, an average of 52% to 55% of the raccoon (Procyon lotor) population on Wolfe Island, Ontario was vaccinated against rabies during proactive trap-vaccinate-release (TVR) operations. However, during 1999, the percent of the population vaccinated declined to 39% and an outbreak (6 cases) of raccoon rabies occurred on the island from December 1999 to January 2000. The raccoon population on Wolfe Island declined dramatically (71% reduction) from 1,067 raccoons (mean density = 8.4/km(2) [6.4-12.4, 95% CI]) during 1999 to 305 raccoons (mean density = 2.4/km(2) [0.87-4.1, 95% CI]) in the spring of 2000. Raccoon density immediately following the outbreak was significantly lower in cells with rabies cases, suggesting that rabies had a negative effect on population size. However, raccoon density had doubled by 1 yr following the outbreak. Movement of raccoons on Wolfe Island was as great as 24 km. Male raccoons moved greater distances than females. Movements to surrounding islands were also noted for raccoons ear tagged on Wolfe Island which indicates the island could serve as a focus for greater geographic rabies spread. Point infection control (PIC) during 2000, TVR during 2001-02, and the aerial distribution of Vaccinia-Rabies Glycoprotein (V-RG) baits during 2000 and 2003-05 were used to eliminate rabies from Wolfe Island. No cases have been detected since late January 2000 (to February 2007).

Susceptibilidad canina a rabia después de una campaña de vacunación en zonas endémicas del Perú

Objective: To determine the level of immune response after a mass vaccination campaign against rabies in two areas which presented cases of canine rabies in the last years. Materials and methods: A serologic survey was carried out in 101 and 199 dogs located respectively, in the cities of Tambo Grande (Piura) and Juliaca (Puno) and a rabies serum mouse neutralization test was perform to measure neutralizing antibodies (≥ 0,5 UI/mL) according to area of study, vaccination antecedents, age and sex of the dog. Results: After three months of the rabies campaign 32% of all dogs were properly protected, 66% had vaccination antecedents and only 44% of the vaccinated dogs had antibodies (> 0,1 UI/mL). A greater protection against rabies was found in Juliaca than in Tambo Grande in vaccinated dogs (51 vs 34%, p 0,05). Conclusions: This study found that there is a poor immune response against rabies in the districts of Tambo Grande, and Juliaca, making them very susceptible to develop dog rabies outbreaks.

Low-coverage vaccination strategies for the conservation of endangered species

The conventional objective of vaccination programmes is to eliminate infection by reducing the reproduction number of an infectious agent to less than one, which generally requires vaccination of the majority of individuals. In populations of endangered wildlife, the intervention required to deliver such coverage can be undesirable and impractical; however, endangered populations are increasingly threatened by outbreaks of infectious disease for which effective vaccines exist. As an alternative, wildlife epidemiologists could adopt a vaccination strategy that protects a population from the consequences of only the largest outbreaks of disease. Here we provide a successful example of this strategy in the Ethiopian wolf, the world's rarest canid, which persists in small subpopulations threatened by repeated outbreaks of rabies introduced by domestic dogs. On the basis of data from past outbreaks, we propose an approach that controls the spread of disease through habitat corridors between subpopulations and that requires only low vaccination coverage. This approach reduces the extent of rabies outbreaks and should significantly enhance the long-term persistence of the population. Our study shows that vaccination used to enhance metapopulation persistence through elimination of the largest outbreaks of disease requires lower coverage than the conventional objective of reducing the reproduction number of an infectious agent to less than one.

Legislating Fear and the Public Health in Gilded Age Massachusetts

Between 1876 and 1881 Massachusetts experienced an outbreak of human rabies (hydrophobia). The entire state--the Governor, the legislature, the State Board of Health, newspapers, and the citizenry and elected officials of every town and city--reacted to the disease. Central to the response was the Commonwealth's legislature--called the General Court. Through public hearings, their own debates, and the passage of legislation, it resolved widespread fear and anger, mediated conflicting concepts of disease, and promoted social solidarity in the face of an epidemic. This article first narrates the General Court's legislative actions; it then examines the conflicting understandings of disease causality; finally, it explores the social and political rituals the legislature drew upon to deal with this public health crisis. Arguing that public health legislation is simultaneously instrumental and symbolic, this article demonstrates that attention to both enriches the study of epidemics, historical and yet to come.

Brotes de rabia humana transmitida por vampiros en los municipios de Bajo y Alto Baudó, departamento del Chocó, Colombia 2004-2005

During months May to July 2004, a rabies outbreak in the Embera community of Birrinchao, in the Purricha river basin department of Choc6 was reported with 14 human deaths. Another rabies outbreak was reported in January 2005 in the black communities of Pató and Nauca in the neighboring municipality of Alto Baudó with 3 human deaths. To describe the largest outbreaks of human rabies transmitted by vampire bats reported in Colombia to date. To describe the diagnostic laboratory techniques used, and the activities undertaken for the control of rabies in the area. To discuss the epidemiologic significance and public health implications of these rabies outbreaks. Rabies diagnosis was achieved by direct immunofluorescence, inoculation of mice and immunohistochemistry. Typing of the virus was achieved by indirect immunofluorescence using monoclonal antibodies. Rabies control activities were undertaken in Bajo Baudó consisting in a population census, human vaccination and application of antirabies sera, vaccination of dogs and cats, and application of anticoagulant to bats. Four human cases were confirmed as positive for rabies in both rabies outbreaks. Another 13 rabies cases in humans were inferred by strong epidemiological links. Rabies antigenic variant 3 was identified in the samples studied. Rabies control activities were conducted for a human rabies outbreak caused by vampire bats. The human rabies outbreak in Bajo Baudó has been the largest reported in Colombia. It was caused by vampire bats, showing that these animals are a threat for human health. The implementation of control strategies for this kind of epizootic outbreaks is needed in South America. It remains unknown whether there is a link between this outbreak and one reported 6 months later in the neighboring municipality of Alto Baudó.

Bat-transmitted Human Rabies Outbreaks, Brazilian Amazon

Abstract We describe 2 bat-transmitted outbreaks in remote, rural areas of Portel and Viseu Municipalities, Pará State, northern Brazil. Central nervous system specimens were taken after patients' deaths and underwent immunofluorescent assay and histopathologic examination for rabies antigens; also, specimens were injected intracerebrally into suckling mice in an attempt to isolate the virus. Strains obtained were antigenically and genetically characterized. Twenty-one persons died due to paralytic rabies in the 2 municipalities. Ten rabies virus strains were isolated from human specimens; 2 other cases were diagnosed by histopathologic examination. Isolates were antigenically characterized as Desmodus rotundus variant 3 (AgV3). DNA sequencing of 6 strains showed that they were genetically close to D. rotundus–related strains isolated in Brazil. The genetic results were similar to those obtained by using monoclonal antibodies and support the conclusion that the isolates studied belong to the same rabies cycle, the virus variants found in the vampire bat D. rotundus.

Bat-transmitted Human Rabies Outbreaks, Brazilian Amazon

We describe 2 bat-transmitted outbreaks in remote, rural areas of Portel and Viseu Municipalities, Pará State, northern Brazil. Central nervous system specimens were taken after patients' deaths and underwent immunofluorescent assay and histopathologic examination for rabies antigens; also, specimens were injected intracerebrally into suckling mice in an attempt to isolate the virus. Strains obtained were antigenically and genetically characterized. Twenty-one persons died due to paralytic rabies in the 2 municipalities. Ten rabies virus strains were isolated from human specimens; 2 other cases were diagnosed by histopathologic examination. Isolates were antigenically characterized as Desmodus rotundus variant 3 (AgV3). DNA sequencing of 6 strains showed that they were genetically close to D. rotundus–related strains isolated in Brazil. The genetic results were similar to those obtained by using monoclonal antibodies and support the conclusion that the isolates studied belong to the same rabies cycle, the virus variants found in the vampire bat D. rotundus.

Bat-transmitted human rabies outbreaks, Brazilian Amazon.

We describe 2 bat-transmitted outbreaks in remote, rural areas of Portel and Viseu Municipalities, Pará State, northern Brazil. Central nervous system specimens were taken after patients' deaths and underwent immunofluorescent assay and histopathologic examination for rabies antigens; also, specimens were injected intracerebrally into suckling mice in an attempt to isolate the virus. Strains obtained were antigenically and genetically characterized. Twenty-one persons died due to paralytic rabies in the 2 municipalities. Ten rabies virus strains were isolated from human specimens; 2 other cases were diagnosed by histopathologic examination. Isolates were antigenically characterized as Desmodus rotundus variant 3 (AgV3). DNA sequencing of 6 strains showed that they were genetically close to D. rotundus-related strains isolated in Brazil. The genetic results were similar to those obtained by using monoclonal antibodies and support the conclusion that the isolates studied belong to the same rabies cycle, the virus variants found in the vampire bat D. rotundus.

BEHAVIOR, MOVEMENTS, AND DEMOGRAPHICS OF RABID RACCOONS IN ONTARIO, CANADA: MANAGEMENT IMPLICATIONS

During 1999-2003, 127 cases of raccoon variant rabies were reported in raccoons (Procyon lotor) and striped skunks (Mephitis mephitis) in Ontario, Canada. Raccoons accounted for 98% (125/127) of the reported cases with behaviors/conditions including aggression, fighting with dogs, ataxia, vocalizations, appearance of being sick, and the presence of porcupine (Erethizon dorsatum) quills. Seventy-eight percent of the rabid raccoons were adults. Juveniles were underrepresented (22%) compared with the adult/juvenile ratios found in nonrabid Ontario raccoon populations. Of the known aged raccoons, 83% were < or = 3 yr of age, and 22% of the rabid adult female raccoons had evidence of having had a litter during the year in which they were found to be rabid. The majority of rabid raccoons were reported during the fall, winter, and spring, suggesting a relationship between raccoon behavioral activities such as denning and breeding and the timing of rabies outbreaks. Multiple cases of raccoon rabies occurred at several barns, suggesting that those structures serve as focal points of rabies transmission as a result of denning activities. Movements of five rabid raccoons (range 1,564-4,143 m) were not different from movements of nonrabid raccoons in Ontario. Sixty-six percent of the rabid animals were submitted by government staff, stressing the importance of those agencies in rabies control and surveillance operations. Increased knowledge of the behaviors of rabid raccoons should assist in the development of management strategies for rabies.

Molecular epidemiology of rabies from Maranhão and surrounding states in the northeastern region of Brazil

Although many outbreaks of rabies have been reported in northern Brazil, few epidemiological studies of these outbreaks have been undertaken. In this study, molecular epidemiological analyses were performed using 41 rabies virus samples isolated in the Maranhão (MA), Pará (PA), and Tocantins (TO) states of northeastern Brazil. A 599-bp region of the glycoprotein (G) gene was first amplified from each sample by RT-PCR, then sequenced and subjected to phylogenetic analysis. A phylogenetic tree divided the 41 isolates into two clades: Clade I was associated with terrestrial carnivores and Clade II was associated with vampire bats. The Clade I isolates were further sub-divided into two groups. The first group was closer to carnivore isolates that predominate in central Brazil, whereas the second group more closely resembled wild fox isolates from the northeastern coastal state of Paraíba (PB). MA isolates of Clade II formed an entirely separate group. These results demonstrate that bat- and dog-transmitted rabies occur in northwestern Brazil.

Development of vaccination strategies for the management of rabies in African wild dogs

The standard objective of a vaccination strategy is to reduce the reproductive ratio, R 0, defined as the number of secondary host infections arising directly from introduction of a single infected individual into an otherwise fully susceptible population, to below 1. This ensures that only very small outbreaks are likely to arise. However, this objective usually requires a high level of vaccination coverage that is often expensive and logistically difficult to achieve. For the purposes of conserving rare species that are threatened by outbreaks of infectious disease, population persistence may be assured by a vaccination strategy designed to suppress only the largest outbreaks of disease that reduce the population to below a minimum viable population size. Such strategies targeting only a viable minimal ‘core’ of the population are likely to be logistically less demanding. Here we explore how these core vaccination strategies might be designed for African wild dogs ( Lycaon pictus), an endangered canid species whose remaining populations are threatened by rabies outbreaks. We develop and analyse a population viability model with an explicit epidemiological model embedded within it. The model predicts that core vaccination campaigns, using vaccines that provide two years of immunity, and targets 30–40% of individuals within a population every 1–2 years would be successful in ensuring persistence of small populations, and required coverage levels can be even lower in larger populations. This strategy appears robust to synchronized introduction of rabies into packs, possible Allee effects, and the use of vaccines providing only one year of immunity.

An integrated disease management strategy for the control of rabies in Ethiopian wolves

Infectious diseases pose an important extinction risk for a number of endangered carnivore populations. Wild canids are particularly susceptible to generalist pathogens transmitted from domestic dogs – particularly rabies virus and canine distemper virus (CDV). Here we present a review of rabies as a threat to Ethiopian wolves, an endangered canid restricted to a few isolated Afro-alpine ranges in the Ethiopian highlands, and the impact of rabies on the largest population in the Bale Mountains. In the Bale Mountains, two confirmed rabies outbreaks among Ethiopian wolves in 1991–1992 and 2003–2004 were each responsible for over 70% mortality among focal packs and a third rabies outbreak was suspected in 1990. This review also presents an integrated disease management strategy for Ethiopian wolves combining long-term population monitoring, disease surveillance, conventional and emergency vaccination programs, and advanced modelling techniques.

Rabies, an Emerging Disease in Korea

Since the first rabies case was reported in a dog in 1907, the disease was enzootic up to 1975 in Korea. After a steady decrease in the number of rabies cases from 1976 to 1984, no case was reported for 8 years from 1985 to 1992. Then, a resurgence of the disease was noted in 1993, and a continuous increase of rabies cases was observed during the following years. This report provides information on rabies in South Korea during the reemerging period 1993-2003. A total of 364 rabies cases in five different animal species and five deaths in human beings as a result of rabies were reported. Cattle and dogs accounted for 46.4% and 40.4% of total animal cases, respectively, and raccoon dogs commanded an overwhelming majority (44/48) of rabies cases in wildlife animal species. All animal and human rabies cases occurred only in two provinces, Gyeonggi and Gangwon; majority of them in two counties of Gyeonggi and one county of Gangwon province that border the demilitarized zone. From the three counties, the disease continued to expand to the other areas of the two provinces. The average monthly frequency of animal rabies cases during the 11-year period peaked in January, and the incidence was highest during winter. There were three major rabies outbreaks in animals and the number of animal rabies cases increased with time. Data indicate that the temporal patterns were attributable to the ethology of raccoon dogs in the areas of outbreak.

動物由来感染症への対策

A world trend such as the free trade agreement (FTA) promoted by the World Trade Organization ( WTO) results in an expansion of both importation and exportation of industrial materials, grain, food products and domestic animals, as well as pets and wild animals. Nowadays not only foods but also various kinds of animals are arrived from all over the world to Japan, and an increase in the risk for invasion of zoonoses from abroad to Japan has been pointed out for many years. Actually, BSE, O-157, highly pathogenic avian influenza (HPAI) etc., invaded into Japan within recent several years, and a possibility of the outbreak of rabies, plaque or tularemia which might be introduced by imported animals is still high. In this article, I discuss the risk for zoonoses from the following points. They are "from animal to human, background of the world wide expansion of zoonoses, a warning to human being from nature, zoonosis control strategy, and future problems on zoonosis to be dissolved".

Diagnóstico laboratorial da raiva na região oeste do Estado de São Paulo

The Pólo da Alta Sorocabana laboratory, Presidente Prudente, SP, Brazil, and the Biological Institute in São Paulo State, performed an evaluation of rabies diagnosis from 1996 to 2003 in the west region of São Paulo State. For the tests, the laboratories used direct immunofluorescence and mice inoculation in 4,950 samples, that were sent for analysis involving dogs, cats, cattle, chiroptera (bats) and other animals. According to the results, the laboratories found 74 positive samples; of which 58 (78.4%) were non-hematophagous bats and 16 (21.6%) related to cattle. The present epidemiological study verified that in spite of the high positive index in chiroptera compared to the other species, there was not an outbreak of rabies in the species in the region of Presidente Prudente, from 1996 to 2003 but a rise in the positive index due to a marked increase in the number of chiroptera samples sent to the laboratories for virus rabies research.

Sinais clínicos, distribuição das lesões no sistema nervoso e epidemiologia da raiva em herbívoros na região Nordeste do Brasil

Descrevem-se 24 surtos de raiva em bovinos (25 casos), 4 em eqüinos (5 casos), 2 em caprinos (2 casos) e 2 em ovinos (4 casos). Todos os surtos ocorreram na Paraíba, exceto um em eqüinos que ocorreu no Rio Grande do Norte. Todos os surtos, com a exceção de um em ovinos, foram transmitidos provavelmente por morcegos hematófagos; no entanto, não se descarta a possibilidade de transmissão por raposas (Dusicyon vetulus). Os sinais clínicos foram representativos da localização das lesões no sistema nervoso central (SNC). Em bovinos os sinais eram, principalmente, da forma paralítica, causados por lesões da medula, tronco encefálico e cerebelo; mas alguns animais apresentaram depressão, excitação e outros sinais associados a lesões cerebrais. Três dos 5 eqüinos apresentaram sinais de lesões cerebrais e 2 apresentaram a forma paralítica. De 4 ovinos e 2 caprinos, 4 apresentaram a forma paralítica, mas em um caprino e um ovino os sinais foram predominantemente de lesões cerebrais. Todos os animais afetados, exceto um caprino, tiveram um curso clínico de 2-8 dias. As únicas lesões macros-cópicas observadas foram a dilatação da bexiga em 4 bovinos e a dilatação da ampola retal em 2. Dois cavalos apresentaram lesões da pele causadas por traumatismos. As lesões histológicas foram de encefalomielite e meningite difusa não supurativa. Nos eqüinos e em um caprino com evolução clínica de 35 dias as lesões foram mais severas, observando-se necrose neuronal, neuronofagia e presença de esferóides axonais. Corpúsculos de Negri foram observados em 87% (20/23) dos bovinos examinados e em 83% (5/6) dos ovinos e caprinos. Nessas 3 espécies os corpúsculos foram mais freqüentes no cerebelo, mas ocorreram também no tronco encefálico, medula e cérebro. Em cavalos, corpúsculos de Negri foram menos numerosos, sendo observados somente no córtex de um animal e no córtex e hipocampo em outro. No gânglio trigeminal, as lesões histológicas e os corpúsculos de Negri foram menos freqüentes que no SNC. Esses resultados mostram que na raiva dos herbívoros os sinais clínicos e a distribuição das lesões histológicas do SNC são variáveis, e que para o correto diagnóstico da enfermidade são necessários um bom exame clínico e o estudo histológico das diferentes regiões do SNC. Sugere-se, também, que perante resultados negativos nos testes de imunofluo-rescência e inoculação em camundongos, estes devam ser repetidos com amostras de diferentes regiões do SNC. Utilizando-se dados sobre a freqüência de doenças, de 4 laboratórios de diagnóstico, foi realizada uma estimativa das mortes de bovinos causadas pela raiva, anualmente, em 3 Estados. Na Paraíba, com uma população de 918.262 bovinos, o número de mortes é estimado em 8.609 cabeças por ano. No Mato Grosso do Sul, com uma população de 23 milhões de bovinos, as perdas por raiva são estimadas em 149.500 cabeças e, no Rio Grande do Sul, com uma população de 13 milhões de bovinos, as mortes são estimadas em 13.000 a 16.250 animais por ano. Se estas estimativas forem extrapoladas para todo o Brasil, com 195 milhões de bovinos, as mortes podem ser estimadas em 842.688 cabeças por ano.

Archival study of a Finnish isolate from the 1988/89 rabies outbreak

An archival brain sample from an infected dog taken during the 1988/89 rabies outbreak in Finland was investigated to confirm that it was infected with classical rabies virus (genotype 1). The first 400 base pairs of the virus nucleoprotein gene were then sequenced and used to undertake a phylogenetic comparison between this isolate and a panel of rabies virus sequences from the Baltic region. The Finnish dog isolate was identical to a virus isolated from a raccoon-dog also recorded during the 1988/89 outbreak and closely related to a third isolate from the Russian city of Pskov. The implications of these observations for the possible source of the Finnish outbreak are discussed.