A molecular epidemiological study of rabies epizootics in kudu (Tragelaphus strepsiceros) in Namibia

BACKGROUND: A panel of 37 rabies virus isolates were collected and studied, originating mainly from the northern and central regions of Namibia, between 1980 and 2003. RESULTS: These virus isolates demonstrated a high degree of genetic similarity with respect to a 400 bp region of the nucleoprotein gene, with the virus isolates originating from kudu antelope (n = 10) sharing 97.2–100% similarity with jackal isolates, and 97–100% similarity with those isolated from domestic dogs. Phylogenetic analysis suggested that these viruses were all of the canid rabies biotype of southern Africa. The viruses from kudu were closely associated with jackal isolates (n = 6), bat-eared fox isolates (n = 2) and domestic dog isolates (n = 2) at the genetic level and identical at the amino acid level, irrespective of the year of isolation. CONCLUSION: These data suggest that jackal and kudu may form part of the same epidemiological cycle of rabies in Namibian wildlife, and might demonstrate the close-relationship between rabies virus strains that circulate within Namibia and those that circulate between Namibia and its neighbouring countries such as Botswana and South Africa

Wild Rats, Laboratory Rats, Pet Rats: Global Seoul Hantavirus Disease Revisited.

Recent reports from Europe and the USA described Seoul orthohantavirus infection in pet rats and their breeders/owners, suggesting the potential emergence of a "new" public health problem. Wild and laboratory rat-induced Seoul infections have, however, been described since the early eighties, due to the omnipresence of the rodent reservoir, the brown rat Rattus norvegicus. Recent studies showed no fundamental differences between the pathogenicity and phylogeny of pet rat-induced Seoul orthohantaviruses and their formerly described wild or laboratory rat counterparts. The paucity of diagnosed Seoul virus-induced disease in the West is in striking contrast to the thousands of cases recorded since the 1980s in the Far East, particularly in China. This review of four continents (Asia, Europe, America, and Africa) puts this "emerging infection" into a historical perspective, concluding there is an urgent need for greater medical awareness of Seoul virus-induced human pathology in many parts of the world Given the mostly milder and atypical clinical presentation, sometimes even with preserved normal kidney function, the importance of simple but repeated urine examination is stressed, since initial but transient proteinuria and microhematuria are rarely lacking

Serum neutralization profiles of straw-colored fruit bats (Eidolon helvum) in Makurdi (Nigeria), against four lineages of Lagos bat lyssavirus

Lagos bat lyssavirus (LBV) comprising four lineages (A, B, C and D) can potentially cause the fatal disease rabies. Although LBV-B was initially isolated in Nigeria in 1956, there is no information on LBV lineages circulating in Nigeria. This study was undertaken for the first time to measure the neutralizing antibodies against four lineages of LBVs in straw-colored fruit bats (Eidolon helvum) in Makurdi, Nigeria. Serum samples (n = 180) collected during two periods (November 2017–March 2018 and November 2018–March 2019) from terminally bled bats captured for human consumption were tested using a modified fluorescent antibody virus neutralization (mFAVN) assay. A high proportion of bat sera (74%) neutralized at least one lineage of LBV (with reciprocal titers from 9 to >420.89) and most of them neutralized LBV-A (63%), followed by LBV-D (49%), LBV-C (45%) and LBV-B (24%). The majority of positive sera (75%, n = 100) neutralized multiple LBV lineages while the remaining 25% (n = 33) neutralized only a single lineage, i.e., LBV-A (n = 23), LBV-D (n = 8) and LBV-C (n = 2). None exclusively neutralized LBV-B. The results suggest that exposure to LBV is common in E. helvum and that LBV-A (but not LBV-B) is likely to be circulating in this region of Nigeria.The UK Department for Environment, Food and Rural Affairs (Defra), the Scottish Government and the Welsh Government, the European Union’s Horizon 2020 research and innovation program and University of Pretoria Doctoral Research Bursary.https://www.mdpi.com/journal/virusesdm2022Veterinary Tropical Disease

Serum Neutralization Profiles of Straw-Colored Fruit Bats (Eidolon helvum) in Makurdi (Nigeria), against Four Lineages of Lagos Bat Lyssavirus

Lagos bat lyssavirus (LBV) comprising four lineages (A, B, C and D) can potentially cause the fatal disease rabies. Although LBV-B was initially isolated in Nigeria in 1956, there is no information on LBV lineages circulating in Nigeria. This study was undertaken for the first time to measure the neutralizing antibodies against four lineages of LBVs in straw-colored fruit bats (Eidolon helvum) in Makurdi, Nigeria. Serum samples (n = 180) collected during two periods (November 2017–March 2018 and November 2018–March 2019) from terminally bled bats captured for human consumption were tested using a modified fluorescent antibody virus neutralization (mFAVN) assay. A high proportion of bat sera (74%) neutralized at least one lineage of LBV (with reciprocal titers from 9 to >420.89) and most of them neutralized LBV-A (63%), followed by LBV-D (49%), LBV-C (45%) and LBV-B (24%). The majority of positive sera (75%, n = 100) neutralized multiple LBV lineages while the remaining 25% (n = 33) neutralized only a single lineage, i.e., LBV-A (n = 23), LBV-D (n = 8) and LBV-C (n = 2). None exclusively neutralized LBV-B. The results suggest that exposure to LBV is common in E. helvum and that LBV-A (but not LBV-B) is likely to be circulating in this region of Nigeria

Whole-genome sequencing and phylogenetic analysis of rabies viruses from Jordan

Human fatalities caused by rabies are rarely reported in Jordan; however, domestic animals are more likely to fall victim to rabies compared to wild animals, at least this is the case in Jordan due to the presence of canine rabies. In this study, twelve brain samples from domestic and wild animals suspected of being infected with rabies virus from different regions of Jordan were collected during 2019. Seven of them tested positive using the fluorescent antibody test and real-time SYBR RT-PCR assay. Five specimens were from stray dogs and two from foxes. The whole genome sequences were obtained from the positive samples. Sequence analysis showed that one dog virus from Al Quwaysimah city located in Amman governorate, was closely related to an Israeli strain belonging to a Cosmopolitan ME1a clade. The genomes of the remaining six viruses (four from dogs and two from foxes) collected from different areas of Jordan were genetically-related to each other and clustered together with sequences from Iran and Turkey; all belong to Cosmopolitan ME2 clade. These sequences were analyzed with six other Jordanian rabies virus nucleoprotein (N) gene sequences available in the public database, five of them belong to ME1a clade and one belongs to ME1b clade. Rabies virus whole genome data is scarce across the Middle East. This study provides a better understanding of the molecular epidemiology of rabies virus in the region

Genetic analysis of a rabies virus host shift event reveals within-host viral dynamics in a new host

Host shift events play an important role in epizootics as adaptation to new hosts can profoundly affect the spread of the disease and the measures needed to control it. During the late 1990s, an epizootic in Turkey resulted in a sustained maintenance of rabies virus (RABV) within the fox population. We used Bayesian inferences to investigate whole genome sequences from fox and dog brain tissues from Turkey to demonstrate that the epizootic occurred in 1997 (±1 year). Furthermore, these data indicated that the epizootic was most likely due to a host shift from locally infected domestic dogs, rather than an incursion of a novel fox or dog RABV. No evidence was observed for genetic adaptation to foxes at consensus sequence level and dN/dS analysis suggested purifying selection. Therefore, the deep sequence data were analysed to investigate the sub-viral population during a host shift event. Viral heterogeneity was measured in all RABV samples; viruses from the early period after the host shift exhibited greater sequence variation in comparison to those from the later stage, and to those not involved in the host shift event, possibly indicating a role in establishing transmission within a new host. The transient increase in variation observed in the new host species may represent virus replication within a new environment, perhaps due to increased replication within the CNS, resulting in a larger population of viruses, or due to the lack of host constraints present in the new host reservoir

Renewed Public Health Threat from Emerging Lyssaviruses

Pathogen discovery contributes to our knowledge of bat-borne viruses and is linked to the heightened interest globally in bats as recognised reservoirs of zoonotic agents. The transmission of lyssaviruses from bats-to-humans, domestic animals, or other wildlife species is uncommon, but interest in these pathogens remains due to their ability to cause an acute, progressive, invariably fatal encephalitis in humans. Consequently, the detection and characterisation of bat lyssaviruses continues to expand our knowledge of their phylogroup definition, viral diversity, host species association, geographical distribution, evolution, mechanisms for perpetuation, and the potential routes of transmission. Although the opportunity for lyssavirus cross-species transmission seems rare, adaptation in a new host and the possibility of onward transmission to humans requires continued investigation. Considering the limited efficacy of available rabies biologicals it is important to further our understanding of protective immunity to minimize the threat from these pathogens to public health. Hence, in addition to increased surveillance, the development of a niche pan-lyssavirus vaccine or therapeutic biologics for post-exposure prophylaxis for use against genetically divergent lyssaviruses should be an international priority as these emerging lyssaviruses remain a concern for global public health

Between roost contact is essential for maintenance of European bat lyssavirus type-2 in Myotis daubentonii bat reservoir: 'The Swarming Hypothesis'

Many high-consequence human and animal pathogens persist in wildlife reservoirs. An understanding of the dynamics of these pathogens in their reservoir hosts is crucial to inform the risk of spill-over events, yet our understanding of these dynamics is frequently insufficient. Viral persistence in a wild bat population was investigated by combining empirical data and in-silico analyses to test hypotheses on mechanisms for viral persistence. A fatal zoonotic virus, European Bat lyssavirus type 2 (EBLV-2), in Daubenton's bats (Myotis daubentonii) was used as a model system. A total of 1839 M. daubentonii were sampled for evidence of virus exposure and excretion during a prospective nine year serial cross-sectional survey. Multivariable statistical models demonstrated age-related differences in seroprevalence, with significant variation in seropositivity over time and among roosts. An Approximate Bayesian Computation approach was used to model the infection dynamics incorporating the known host ecology. The results demonstrate that EBLV-2 is endemic in the study population, and suggest that mixing between roosts during seasonal swarming events is necessary to maintain EBLV-2 in the population. These findings contribute to understanding how bat viruses can persist despite low prevalence of infection, and why infection is constrained to certain bat species in multispecies roosts and ecosystems

Tissue distribution of angiotensin-converting enzyme 2 (ACE2) receptor in wild animals with a focus on artiodactyls, mustelids and phocids

Natural cases of zooanthroponotic transmission of SARS-CoV-2 to animals have been reported during the COVID-19 pandemic, including to free-ranging white-tailed deer (Odocoileus virginianus) in North America and farmed American mink (Neovison vison) on multiple continents. To understand the potential for angiotensin-converting enzyme 2 (ACE2)-mediated viral tropism we characterised the distribution of ACE2 receptors in the respiratory and intestinal tissues of a selection of wild and semi-domesticated mammals including artiodactyls (cervids, bovids, camelids, suids and hippopotamus), mustelid and phocid species using immunohistochemistry. Expression of the ACE2 receptor was detected in the bronchial or bronchiolar epithelium of several European and Asiatic deer species, Bactrian camel (Camelus bactrianus), European badger (Meles meles), stoat (Mustela erminea), hippopotamus (Hippopotamus amphibious), harbor seal (Phoca vitulina), and hooded seal (Cystophora cristata). Further receptor mapping in the nasal turbinates and trachea revealed sparse ACE2 receptor expression in the mucosal epithelial cells and occasional occurrence in the submucosal glandular epithelium of Western roe deer (Capreolus capreolus), moose (Alces alces alces), and alpaca (Vicunga pacos). Only the European badger and stoat expressed high levels of ACE2 receptor in the nasal mucosal epithelium, which could suggest high susceptibility to ACE2-mediated respiratory infection. Expression of ACE2 receptor in the intestinal cells was ubiquitous across multiple taxa examined. Our results demonstrate the potential for ACE2-mediated viral infection in a selection of wild mammals and highlight the intra-taxon variability of ACE2 receptor expression, which might influence host susceptibility and infection