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

Evolutionary analysis of rabies virus using the partial Nucleoprotein and Glycoprotein gene in Mumbai region of India

Nearly 1.7 million cases of dog bites are reported every year in India and many cases of animal rabies are left unattended and undiagnosed. Therefore, a mere diagnosis of rabies is not sufficient to understand the epidemiology and the spread of the rabies virus (RV) in animals. There is a paucity of information about the evolutionary dynamics of RV in dogs and its biodiversity patterns in India. In total, 50 dog-brain samples suspected of rabies were screened by the nucleoprotein- (N) and glycoprotein- (G) gene PCR. The N and G genes were subsequently sequenced to understand the molecular evolution in these genes. The phylogenetic analysis of the N gene revealed that six isolates in the Mumbai region belonged to a single Arctic lineage. Time-scaled phylogeny by Bayesian coalescent analysis of the partial N gene revealed that the time to the most recent common ancestor (TMRCA) for the sequences belonged to the cluster from 2006.68 with a highest posterior density of 95 % betweeen 2005-2008, which is assigned to Indian lineage I. Migration pattern revealed a strong Bayes factor between Mumbai to Delhi, Panji to Hyderabad, Delhi to Chennai, and Chennai to Chandigarh. Phylogenetic analysis of the G gene revealed that the RVs circulating in the Mumbai region are divided into three lineages. Time-scaled phylogeny by the Bayesian coalescent analysis method estimated that the TMRCA for sequences under study was from 1993 and Indian clusters was from 1962. In conclusion, the phylogenetic analysis of the N gene revealed that six isolates belonged to single Arctic lineages along with other Indian isolates and they were clustered into a single lineage but divided into three clades based on the G-gene sequences. The present study highlights and enhances the current molecular epidemiology and evolution of RV and revealed strong location bias and geographical clustering within Indian isolates on the basis of N and G genes.

Paralytic rabies in a goat

Background

Paralytic form of rabies is frequent in cattle in Latin America, but it is uncommon in goats. There are few clinical reports on furious rabies affecting goats, and the sporadic cases of rabid goats from surveillance programs worldwide lack clinical data. Furthermore, few studies reported the cerebrospinal fluid findings in rabid livestock.

Case presentation

On a farm in Midwestern Brazil, six of 47 Saanen goats died within one week. No vaccination protocols were implemented on the farm and the owner stated bat bites history on the livestock. Although rabies is endemic in Brazil, livestock vaccination is not mandatory. One 1-year-old buck was evaluated and showed non-specific clinical signs evolving within 12-h to nervous signs. Cerebrospinal fluid analysis revealed mononuclear pleocytosis, hyperproteinemia and high glucose levels. At necropsy, no gross lesions were present. Microscopically, discrete to moderate perivascular lymphoplasmacytic cuffing in gray and white matter, neuronal necrosis, neuronophagia, and mononuclear ganglioneuritis was observed in the brainstem and cervical spinal cord. Immunohistochemistry revealed strong anti-rabies virus immunostaining. Fresh central nervous system samples were positive for rabies in direct fluorescent antibody test (dFAT) and mouse intracerebral inoculation test (MIT). Exposed livestock recommendations included immediate vaccination, a strict isolation period of 90 days, and booster vaccinations during the third and eighth weeks.

Conclusion

IHC revealed the widespread distribution of rabies virus antigen in the goat’s CNS, contrasting the discrete pathological changes. In this goat, definitive diagnosis of paralytic rabies was obtained through the association of epidemiological, clinical, laboratorial, pathological findings (histology and IHC) and gold standard confirmatory tests (dFAT and MIT).

Molecular epidemiological tracing of a cattle rabies outbreak lasting less than a month in Rio Grande do Sul in southern Brazil

Background

Vampire bat-transmitted cattle rabies cases are typically encountered in areas where the disease is endemic. However, over the period of a month in 2009, an outbreak of cattle rabies occurred and then ended spontaneously in a small area of the Rio Grande do Sul State in southern Brazil. To investigate the epidemiological characteristics of this rabies outbreak in Rio Grande do Sul, 26 nucleotide sequences of rabies virus (RABV) genomes that were collected in this area were analyzed phylogenetically.

Results

Nucleotide sequence identities of the nucleoprotein gene and G–L intergenic region of the 26 RABVs were greater than 99.6 %. Phylogenetic analysis showed that all RABVs clustered with the vampire bat-related cattle RABV strains and that the RABVs were mainly distributed in southern Brazil.

Conclusions

The findings of the present study suggested that a small population of rabid vampire bats carrying a single RABV strain produced a spatiotemporally restricted outbreak of cattle rabies in southern Brazil.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-016-1898-5) contains supplementary material, which is available to authorized users.

The Role of Bats as Reservoir Hosts of Emerging Neuroviruses

Recent studies have clearly shown that bats are the reservoir hosts of a wide diversity of novel viruses with representatives from most of the known animal virus families. In many respects bats make ideal reservoir hosts for viruses: they are the only mammals that fly, thus assisting in virus dispersal; they roost in large numbers, thus aiding transmission cycles; some bats hibernate over winter, thus providing a mechanism for viruses to persist between seasons; and genetic factors may play a role in the ability of bats to host viruses without resulting in clinical disease. Within the broad diversity of viruses found in bats are some important neurological pathogens, including rabies and other lyssaviruses, and Hendra and Nipah viruses, two recently described viruses that have been placed in a new genus, Henipaviruses in the family Paramyxoviridae. In addition, bats can also act as alternative hosts for the flaviviruses Japanese encephalitis and St Louis encephalitis viruses, two important mosquito-borne encephalitogenic viruses, and bats can assist in the dispersal and over-wintering of these viruses. Bats are also the reservoir hosts of progenitors of SARS and MERS coronaviruses, although other animals act as spillover hosts. This chapter presents the physiological and ecological factors affecting the ability of bats to act as reservoirs of neurotropic viruses, and describes the major transmission cycles leading to human infection.

Rabies Risk: Difficulties Encountered during Management of Grouped Cases of Bat Bites in 2 Isolated Villages in French Guiana

In French Guiana, from 1984 to 2011, 14 animal rabies cases and 1 human rabies case (2008) were diagnosed. In January 2011, vampire-bat attacks occurred in 2 isolated villages. In mid-January, a medical team from the Cayenne Centre for Anti-Rabies Treatment visited the sites to manage individuals potentially exposed to rabies and, in April, an anti-rabies vaccination campaign for dogs was conducted. Twenty individuals were bitten by bats in 1 month, most frequently on the feet. The median time to start management was 15 days. The complete Zagreb vaccination protocol (2 doses on day 0 and 1 dose on days 7 and 21) was administered to 16 patients, 12 also received specific immunoglobulins. The antibody titration was obtained for 12 patients (different from those who received immunoglobulins). The antibody titers were ≥0.5 EU/mL for all of them. The serology has not been implemented for the 12 patients who received immunoglobulins. Accidental destruction of a vampire-bat colony could be responsible for the attacks. The isolation and absence of sensitization of the populations were the main explanations for the management difficulties encountered. Sensitization programs should be conducted regularly.

Rabies is a disease almost invariably fatal in humans once the first clinical signs appear. In French Guiana bats represent the virus reservoir, especially vampire bats. From 1984 to 2011, 14 animal rabies cases and 1 human rabies case (2008) were diagnosed. In case of bat bite, anti-rabies immunoglobulins (RIG) and rabies vaccine must be rapidly administrated. The specific rabies management is exclusively performed by Centre for Anti-Rabies Treatment (CART), located at the Institut Pasteur in Cayenne, the prefecture of French Guiana, and 6 Anti-Rabies Treatment Outposts distributed along the coastal edge and along the two main rivers. Only a CART physician can administer RIG. In January 2011, vampire-bat attacks occurred in 2 isolated villages. In mid-January, a medical team from the CART visited the sites to manage individuals potentially exposed to rabies and, in April, an anti-rabies vaccination campaign for dogs was conducted. The most relevant contribution of this study is to underline difficulties to provide rabies post-exposure prophylaxis to remote populations exposed to bat rabies in the Amazonian region and to show the lack of awareness of these rural populations concerning rabies and the risk associated to vampire bats.

First human rabies case in French Guiana, 2008: epidemiological investigation and control

BACKGROUND

Until 2008, human rabies had never been reported in French Guiana. On 28 May 2008, the French National Reference Center for Rabies (Institut Pasteur, Paris) confirmed the rabies diagnosis, based on hemi-nested polymerase chain reaction on skin biopsy and saliva specimens from a Guianan, who had never travelled overseas and died in Cayenne after presenting clinically typical meningoencephalitis.

METHODOLOGY/PRINCIPAL FINDINGS

Molecular typing of the virus identified a Lyssavirus (Rabies virus species), closely related to those circulating in hematophagous bats (mainly Desmodus rotundus) in Latin America. A multidisciplinary Crisis Unit was activated. Its objectives were to implement an epidemiological investigation and a veterinary survey, to provide control measures and establish a communications program. The origin of the contamination was not formally established, but was probably linked to a bat bite based on the virus type isolated. After confirming exposure of 90 persons, they were vaccinated against rabies: 42 from the case's entourage and 48 healthcare workers. To handle that emergence and the local population's increased demand to be vaccinated, a specific communications program was established using several media: television, newspaper, radio.

CONCLUSION/SIGNIFICANCE

This episode, occurring in the context of a Department far from continental France, strongly affected the local population, healthcare workers and authorities, and the management team faced intense pressure. This observation confirms that the risk of contracting rabies in French Guiana is real, with consequences for population educational program, control measures, medical diagnosis and post-exposure prophylaxis.

Caracterização molecular do vírus da raiva isolado de Desmodus rotundus capturados no Estado do Rio de Janeiro

Caracterizou-se filogeneticamente o vírus da raiva, isolado de morcegos hematógafos (Demodus rotundus). Cento e noventa e nove D. rotundus foram capturados em cinco abrigos, no Norte e Noroeste do Estado do Rio de Janeiro e sul do Espírito Santo. Sete deles foram positivos para a raiva. Amostras desses vírus foram sequenciadas e comparadas com sequências provenientes de diversos estados brasileiros. As sequências de vírus da raiva isoladas, na região norte do Estado do Rio de Janeiro, mostraram características que as distinguem de amostras de vírus isoladas em outras regiões do país, no entanto foram idênticas às isoladas de bovinos no noroeste do Rio de Janeiro.

Updated list of bat species positive for rabies in Brazil

This paper presents an updated list of bat species positive for rabies in Brazil. It was developed based on database research via the internet, of international and national literature and annals of the most important technical and scientific meetings related to rabies and chiroptera in Brazil from 1996 to 2009. The new list of rabies positive bats consists of 41 species, belonging to 25 genera and three families: Phyllostomidae 43.9%, Vespertilionidae 29.3% and Molossidae 26.8%. In addition, questions were raised regarding the lack of data, including sex, age, circumstances and location of bat capture and incomplete and outdated species identification. Results of genetic and antigenic studies performed on Brazilian rabies positive bats were shown.

Molecular characterization of Rabies Virus isolates from dogs and crab-eating foxes in Northeastern Brazil

Thirty-eight samples of Rabies Virus isolated from dogs and crab-eating foxes (Cerdocyon thous) in Northeastern Brazil were characterized genetically by analyzing the G gene and the psi region. The results show that there are two groups of Rabies Virus lineages circulating among domestic and wild animals in the region. The topologies of the phylogenetic trees of the G gene and psi region are similar and reveal the existence of geographic groups. The genetic diversity of the lineages isolated from wild animals (wild group) was approximately twice that of the lineages isolated from domestic animals (domestic group), and the genetic distance between the two groups was 9.93%. Polymorphism analysis revealed specific intra- and inter-group molecular signatures for both the G gene and psi region. Together with the analysis of the N gene undertaken previously, the results of this study confirm the existence of a Rabies Virus phylogroup in Northeastern Brazil (NB) circulating in the C. thous population, making this species a rabies biotype in the region.

Characterization of Rabies virus isolated from canids and identification of the main wild canid host in Northeastern Brazil

The rabies cases in dogs and wild canids in Northeastern Brazil are a public and animal health problem. This paper describes the identities of the coding region of the N-gene of Rabies virus (RABV) isolated in canids from Northeastern Brazil. The genetic tree generated using the sequence data described here divided the cluster BRAZILAN CANIDS into two subclusters (DOG-RELATED STRAINS and WILD CANID-RELATED STRAINS) with identities greater than those already described. The two subclusters are sub-divided into geographic groups related to the origin of the isolates, suggesting a long-standing ecological coexistence of the sequence types characteristic of the groups. This article also analyzes the 513-nucleotide stretch of the mitochondrial DNA control region of rabies-positive canids from Northeastern Brazil with a view to identifying the main RABV host among them. Among the four species of wild canids found in the region, two (Cerdocyon thous and Pseudalopex vetulus) are frequently associated with rabies. Phylogenetic analysis of sequence data generated from mtDNA suggests that C. thous is the main wild canid host in the region. The results obtained in this study are in concordance with the zoology and ecology of wild canids, and thus, help improve epidemiologic vigilance of rabies and allow a more targeted control of the disease.

Phylogenetic Characterization of Rabies Virus Isolates from Carnivora in Brazil

The incidence of canine rabies has been widely reported in Brazil, and new rabies virus (RV) variants, genetically similar to canine RV, have recently been isolated from foxes. In order to derive the epidemiological characteristics of Brazilian Carnivora RV, Brazilian RVs isolated from dogs, cats, and foxes were genetically analyzed. Brazilian Carnivora RV isolates were divided into 2 main lineages. The predominant lineage was found in dogs and cats, which included the Argentinean and Bolivian Carnivora RV isolates, and was extensively distributed throughout Brazil and surrounding countries. The other lineage consisted of three sublineages containing Brazilian dog and fox RV isolates, with the dog sublineages located on an internal branch of 2 fox sublineages, suggesting that RV transmission events might have occurred between foxes and dogs in the past. These results suggest that contact between dogs and wildlife has the potential to generate new rabies variants and that it is important to control RV infection cycles in both dogs and wildlife to prevent spread of rabies infection.