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Antibody response to Raboral VR-G® oral rabies vaccine in captive and free-ranging black-backed jackals (Canis mesomelas)
2022
Koeppel,Katja N. | Geertsma,Peter | Kuhn,Brian F. | van Schalkwyk,Ockert L. | Thompson,Peter N.
Rabies is a zoonotic disease that remains endemic in large parts of southern Africa because of its persistence in wildlife and domestic dog vectors. The black-backed jackals (Canis mesomelas) is primarily the wildlife vector responsible for rabies outbreaks in northern parts of South Africa. Two trials were carried out to investigate antibody responses to the oral rabies vaccine Raboral V-RG® in black-backed jackals under captive and free-ranging conditions. In captive jackals 10/12 (83%; 95% confidence interval [CI]: 52% - 98%), seroconverted after single oral vaccination. Nine captive jackals had protective antibody titres (> 0.5 IU/mL) at 4 weeks (median: 2.1 IU/mL; inter quartile range [IQR]: 0.6-5.7) and 10 jackals had at 12 weeks (median: 3.5 IU/mL; IQR: 1.5-8.3) and three maintained antibody titres for up to 48 weeks (median: 3.4 IU/mL; IQR: 2.0-6.3). Four sites were baited with Raboral V-RG® vaccine for wild jackals, using fishmeal polymer and chicken heads. Baits were distributed by hand or from vehicle at three sites in north-eastern South Africa, with an average baiting density of 4.4 baits/km² and at one site in central South Africa, at 0.12 baits/km². This resulted in protective antibody titres in 3/11 jackals (27%; 95% Cl: 6-61) trapped between 3 and 12 months after baiting in north-eastern South Africa, compared with 4/7 jackals (57%; 95% Cl: 18-90) trapped after 3-18 months in central South Africa. This study shows the potential utility of oral rabies vaccination for the control of wildlife-associated rabies in north-eastern and central South Africa, but extensive studies with wider distribution of bait are needed to assess its potential impact on rabies control in wild jackals.
Show more [+] Less [-]Vaccine-induced rabies in a red fox in Poland
2022
Smreczak Marcin | Orłowska Anna | Müller Thomas | Freuling Conrad M. | Kawiak-Sadurska Magdalena | Trębas Paweł
Rabies as a zoonosis threatens public health worldwide. Several thousand people die each year of infections by the rabies virus (RABV). Oral rabies vaccination (ORV) of wildlife was successfully implemented in many European countries and led to rabies being brought under control there. In Poland, ORV was introduced in 1993 using vaccines containing an attenuated strain of the rabies virus. However, attenuated rabies viruses may have residual pathogenicity and cause the disease in target and non-target animals.
Show more [+] Less [-]Apoptosis in natural rabies virus infection in dogs
2016
Vural, Sevil Atalay | Bozkurt, Mehmet Fatih | Ozkara, Ali | Alcigir, Mehmet Eray | Ilhan, Fatma Sayin
Introduction: In the present study apoptosis was investigated in the cornu ammonis and cerebellum of 10 dogs naturally infected with rabies virus. Diagnosis of rabies was based on the results of fluorescent antibody staining and experimental inoculation.Material and Methods: The paraffin tissue sections were stained with haematoxylin and eosin, avidin-biotin complex peroxidase (ABC-P), and terminal deoxynucleotidyl transferase biotin-dUTP nick end-labelling (TUNEL) methods.Results: Histopathological examination revealed encephalomyelitis of varying severity and the presence of Negri bodies. Dense rabies antigens were determined in the motor neurons with ABC-P method. On the other hand, Bcl-2 protein and Bax protein gave positive reaction in seven and five cases, respectively. TUNEL staining demonstrated very marked apoptotic changes in the nuclei of neurons localised deep in the substantia alba of the cerebellum. Similar changes were also determined in perivascular mononuclear cells and glia cells within the substantia alba. No apoptopic changes were found in the motor neurons of the cornu ammonis.Conclusion: The absence of apoptotic changes in the neurons was considered to be the consequence of the necrotic changes that developed in these neurons.
Show more [+] Less [-]Apoptosis in natural rabies virus infection in dogs
2016
Vural Sevil Atalay | Bozkurt Mehmet Fatih | Ozkara Ali | Alcigir Mehmet Eray | Ilhan Fatma Sayin
Introduction: In the present study apoptosis was investigated in the cornu ammonis and cerebellum of 10 dogs naturally infected with rabies virus. Diagnosis of rabies was based on the results of fluorescent antibody staining and experimental inoculation.
Show more [+] Less [-]Vaccine-induced rabies in a red fox in Poland
2022
Smreczak, Marcin | Orłowska, Anna | Müller, Thomas | Freuling, Conrad Martin | Kawiak-Sadurska, Magdalena | Trębas, Paweł
Introduction: Rabies as a zoonosis threatens public health worldwide. Several thousand people die each year of infections by the rabies virus (RABV). Oral rabies vaccination (ORV) of wildlife was successfully implemented in many European countries and led to rabies being brought under control there. In Poland, ORV was introduced in 1993 using vaccines containing an attenuated strain of the rabies virus. However, attenuated rabies viruses may have residual pathogenicity and cause the disease in target and non-target animals. Material and Methods: A red fox carcass was tested as part of national rabies surveillance, and its brain was screened for RABV infection using two conjugates and a fluorescent antibody test (FAT). The rabies virus was isolated in mouse neuroblastoma cells by rabies tissue culture infection test (RTCIT), and viral RNA was detected by heminested reverse transcriptase PCR (hnRT-PCR) as well as by quantitative real-time RT-PCR (rtRT-qPCR). An amplicon of 600 bp was subjected to Sanger sequencing. To differentiate between vaccine and field RABV strains, PCR-restriction fragment length polymorphism (PCR-RFLP) using the Dra I, Msp I, Nla IV and Mbo II restriction endonucleases was performed. Results: The rabies virus was detected in the fox’s brain using FAT, RTCIT and molecular tests. The PCR-RFLP revealed of vaccine-induced rabies, and full-length genome analysis showed 100% nucleotide sequence identity of the isolate with the reference sequences of Street Alabama Dufferin Bern (SAD Bern) vaccine strains and other vaccine-induced rabies virus isolates detected in animals and deposited in GenBank. Conclusion: We detected vaccine-induced rabies for the first time in Poland in a fox during routine rabies surveillance.
Show more [+] Less [-]Determination of the rabies virus variants circulating in Poland in 2021–2023 and their phylogeny with analysis of the strains in the Mazowieckie and Podkarpackie voivodeships
2024
Ciołek Janusz | Orłowska Anna | Smreczak Marcin
Rabies is endemic in Europe and red foxes are the vector and reservoir of the rabies virus (RABV). Based on classification established in the early 1990s, four variants of the rabies virus have been distinguished in Europe. Rabies broke out in January 2021 in the Mazowieckie voivodeship in central north-eastern Poland. The virus spread rapidly, reaching the Świętokrzyskie voivodeship in the central southern part and the Lubelskie voivodeship in the eastern part in the next months. Nine rabies cases were reported in the Podkarpackie voivodeship in south-eastern Poland between 2021 and 2023, mainly in red foxes but also in dogs and wildcat. The aim of the study was the identification of RABV variants in wildlife and domestic animals in Poland between 2021 and 2023.
Show more [+] Less [-]Evaluation of direct metagenomics and target enriched approaches for high-throughput sequencing of field rabies viruses
2019
Orłowska, Anna | Iwan, Ewelina | Smreczak, Marcin | Rola, Jerzy
High-throughput sequencing (HTS) identifies random viral fragments in environmental samples metagenomically. High reliability gains it broad application in virus evolution, host-virus interaction, and pathogenicity studies. Deep sequencing of field samples with content of host genetic material and bacteria often produces insufficient data for metagenomics and must be preceded by target enrichment. The main goal of the study was the evaluation of HTS for complete genome sequencing of field-case rabies viruses (RABVs). The material was 23 RABVs isolated mainly from red foxes and one European bat lyssavirus-1 isolate propagated in neuroblastoma cells. Three methods of RNA isolation were tested for the direct metagenomics and RABV-enriched approaches. Deep sequencing was performed with a MiSeq sequencer (Illumina) and reagent v3 kit. Bioinformatics data were evaluated by Kraken and Centrifuge software and de novo assembly was done with metaSPAdes. Testing RNA extraction procedures revealed the deep sequencing scope superiority of the combined TRIzol/column method. This HTS methodology made it possible to obtain complete genomes of all the RABV isolates collected in the field. Significantly greater rates of RABV genome coverages (over 5,900) were obtained with RABV enrichment. Direct metagenomic studies sequenced the full length of 6 out of 16 RABV isolates with a medium coverage between 1 and 71. Direct metagenomics gives the most realistic illustration of the field sample microbiome, but with low coverage. For deep characterisation of viruses, e.g. for spatial and temporal phylogeography during outbreaks, target enrichment is recommended as it covers sequences much more completely.
Show more [+] Less [-]Factors associated with the rabies vaccination status of dogs in households in Beni City, D.R. Congo
2024
Prince D. Kimpanga | Emery K. Taghembwa | Gauthier M. Mubenga | Jean-Marie T. Makwera | Norbert M. Muhongya | Odrade B. Chabikuli | Justin M. Masumu
Human rabies transmitted by dogs still kills thousands of people each year worldwide. Dog bites are common in the city of Beni (Democratic Republic of Congo), which shows low rabies vaccination coverage. This study aimed to determine the factors associated with the rabies vaccination status of dogs. A cross-sectional analytical study was conducted in the town of Beni among dog owners, during a household survey selected using a multistage sampling. The information sought concerned the knowledge and characteristics of the dog owners as well as the vaccination status of these dogs. Logistic regression was used to investigate associations between the vaccination status of the dogs and the main independent factors. Rabies vaccination coverage in Beni was 26% (95% confidence interval [CI]: 22% – 30%). The main factors associated with the rabies vaccination status of the dog were primary education level of household head (adjusted odds ratio [aOR]:4.8; 95% CI: 1.2– 19.8); university education level of household head (aOR: 5.9; 95% CI: 1.6–22); perceived rabies severity (aOR: 44. 4; 95% CI: 10.4–188), having more than one dog in the household (aOR: 2.6; 95% CI: 1.6–4.3); age range 7–12 months (aOR: 0.2; 95% CI: 0.1–0.6) and confined dog breeding (aOR: 3.9; 95% CI: 1.1–14.9). The low vaccination coverage in Beni requires mass vaccination campaigns against canine rabies targeting the dog owners with low education levels, those raising more than one dog, with stray dogs or dogs less than 12 months old.
Show more [+] Less [-]Duration of immunity after rabies vaccination in dogs: The Rabies Challenge Fund research study
2020
Dodds, W Jean | Larson, Laurie J. | Christine, Kris L. | Schultz, Ronald D.
A prospective study of 65 research beagles kept in a rabies-free environment was undertaken to determine the duration of immunity after they received licensed rabies vaccines. The eventual goal was to extend mandated rabies booster intervals to 5 or 7 years and help reduce the risk of vaccine-associated adverse events. Three groups of dogs were vaccinated with 1 of 2 commercial rabies vaccines or saline at 12 and 15 weeks of age. Beginning 5 years 5 months later, vaccinated and unvaccinated dogs were challenged with virulent rabies virus and observed for 90 days over a series of 3 trials. Humoral and cellular immune responses were examined by serology and flow cytometry. Brain tissue from all challenged dogs was tested for rabies virus. Challenge trial 1 was confounded due to insufficiently virulent virus. In trials 2 and 3 virulent challenge provided 100% mortality in controls. Vaccinate survival was 80% (4/5) after 6 years 7 months, 50% (6/12) after 7 years 1 month, and 20% (1/5) after 8years 0 months. Antibody responses 12 days post-challenge correlated strongly with survival. In a separate non-challenge trial, administration of either a recombinant or a killed rabies vaccine demonstrated memory antibody responses 6 years 1 month after initial vaccination compared with unvaccinated controls. Our data demonstrated that i) duration of immunity to rabies in vaccinated dogs extends beyond 3 years; ii) immunologic memory exists even in vaccinated dogs with serum antibody titer < 0.1 IU/mL; and iii) non-adjuvanted recombinant rabies vaccine induces excellent antibody responses in previously vaccinated dogs 14 days after administration.
Show more [+] Less [-]L-lactate in cerebrospinal fluid can be used as a biomarker of encephalitis in cattle
2020
Curti, Juliana M. | Queiroz, Gustavo R. | Pereira, Priscilla F. V. | Anjos, Mayara C. | Flaiban, Karina K. M. C. | Lisboa, Julio A. N.
Cerebrospinal fluid (CSF) changes are significant for antemortem diagnoses of some neurological diseases. The aim of this study was to evaluate if the concentration of L-lactate in CSF could be used to differentiate healthy from encephalitic cattle. Cerebrospinal fluid samples from healthy cattle (n = 10) and from those naturally affected by rabies (n = 15), bovine herpesvirus type 5 meningoencephalitis (n = 16), histophilosis (n = 6), or bacterial encephalitis (n = 4), including 1 case of listeriosis, were collected and analyzed. Physical, biochemical (i.e., protein and glucose), and cellular analyses were performed in fresh samples. L-lactate, electrolytes (sodium, potassium, and chloride), calcium, and magnesium concentrations were measured in CSF samples that were kept frozen. L-lactate concentrations were also measured in plasma. Analysis of variance was used for comparison between groups and receiver operating characteristic analysis was performed considering L-lactate in CSF of healthy versus encephalitic cattle. The CSF L-lactate concentration was significantly higher in cattle with bacterial encephalitis than in healthy cattle; however, it did not differ between viral and bacterial encephalitis. The calcium concentrations were lower in cattle with encephalitis. L-lactate concentration in CSF > 3.6 mmol/L can be accepted as a cut-off value to indicate encephalitis. Thus, L-lactate in CSF is important for the diagnosis of encephalitis in cattle. Despite the small number of cases of bacterial encephalitis, it is suggested that L-lactate was not important for the differentiation between viral and bacterial encephalitis. Additional studies with a greater number of observations are necessary to clarify this, specifically in cases of listeriosis.
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