Isolation of Lagos Bat Virus from Water Mongoose

One-sentence summary for table of contents: Lagos bat virus from water mongoose showed strong sequence homology with other Lagos bat virus isolates from South Africa

Lagos Bat Virus, South Africa

Three more isolates of Lagos bat virus were recently recovered from fruit bats in South Africa after an apparent absence of this virus for 13 years. The sporadic occurrence of cases is likely due to inadequate surveillance programs for lyssavirus infections among bat populations in Africa

Rabies virus seroprevalence among dogs in Limpopo National Park and the phylogenetic analyses of rabies viruses in Mozambique

Rabies is considered a neglected disease among many developing Asian and African countries, including Mozambique, where its re-emergence is often attributed to low dog parenteral vaccination coverage. The objectives of this study were two-fold: (1) to assess the level of antibodies against rabies virus in dogs (n = 418) in Limpopo National Park (LNP), and (2) to genetically characterise selected rabies viruses from brain tissue samples collected in 2017 and 2018. To meet the first objective, we used the BioProTM Rabies blocking ELISA antibody kit, and the results were expressed as the percentage of blocking (%PB). Dog sera with PB ≥ 40% were considered positive for antibodies to rabies virus, whereas sera with PB < 40% were negative. Just under ninety percent (89.2%; n = 373) of dogs were seronegative, and the rest (10.8%; n = 45) had detectable levels of rabies virus-specific antibodies. All eight brain tissue samples were positive for rabies virus antigen using a direct fluorescent antibody test and amplified in a quantitative real-time PCR, but only five (n = 4 from dogs and n = 1 from a cat) were amplified in a conventional reverse-transcription PCR targeting partial regions of the nucleoprotein (N) and the glycoprotein (G) genes. All samples were successfully sequenced. Phylogenetically, the rabies viruses were all of dog origin and were very closely related to each other (Africa 1b rabies virus lineage). Furthermore, the sequences had a common progenitor with other rabies viruses from southern Africa, confirming the transboundary nature of rabies and the pivotal role of dogs in maintaining rabies cycles. The study demonstrates the principal application of the BioProTM rabies ELISA antibody for the detection of anti-lyssavirus-specific antibodies in the serum samples of dogs, and most importantly, it highlights the low levels of antibodies against rabies virus in this dog population.The Third Framework Agreement Program “FA 3 III DGD/ITM 2014–2016” Project: “Communities on the move: animal and human health challenges” from the University of Pretoria (UP) and the Directorate-General Development Cooperation and Humanitarian Aid (DGD)/the Institute of Tropical Medicine of Antwerp (ITM) and by Fundo para a Investigação Aplicada e Multissectorial-FIAM.https://www.mdpi.com/journal/pathogensdm2022Centre for Veterinary Wildlife StudiesVeterinary 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.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

Enhanced diagnosis of rabies and molecular evidence for the transboundary spread of the disease in Mozambique

Rabies is a neglected zoonotic disease with veterinary and public health significance, particularly in Africa and Asia. The current knowledge of the epidemiology of rabies in Mozambique is limited because of inadequate sample submission, constrained diagnostic capabilities and a lack of molecular epidemiological research. We wanted to consider the direct, rapid immunohistochemical test (DRIT) as an alternative to the direct fluorescent antibody (DFA) for rabies diagnosis at the diagnostic laboratory of the Central Veterinary Laboratory (CVL), Directorate of Animal Science, Maputo, Mozambique. Towards this aim, as a training exercise at the World Organisation for Animal Health (OIE) Rabies Reference Laboratory in South Africa, we performed the DRIT on 29 rabies samples from across Mozambique. With the use of the DRIT, we found 15 of the 29 samples (52%) to be negative. The DRIT-negative samples were retested by DFA at the OIE Rabies Reference Laboratory, as well as with an established real-time Polymerase chain reaction, confirming the DRIT-negative results. The DRIT-positive results (14/29) were retested with the DFA and subsequently amplified, sequenced and subjected to phylogenetic analyses, confirming the presence of rabies RNA. Molecular epidemiological analyses that included viruses from neighbouring countries suggested that rabies cycles within Mozambique might be implicated in multiple instances of cross-border transmission. In this regard, our study has provided new insights that should be helpful in informing the next steps required to better diagnose, control and hopefully eliminate rabies in Mozambique.The National Research Foundation (NRF) of South Africahttp://www.jsava.co.zaam2017Microbiology and Plant Patholog

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

Spatio-temporal epidemiology of animal and human rabies in northern South Africa between 1998 and 2017

BACKGROUND : Rabies is a fatal zoonotic disease that is maintained in domestic dogs and wildlife populations in the Republic of South Africa. A retrospective study was conducted to improve understanding of the dynamics of rabies in humans, domestic dogs, and wildlife species, in relation to the ecology for three northern provinces of South Africa (Limpopo, Mpumalanga, and North-West) between 1998 and 2017. METHODS : A descriptive epidemiology study was conducted for human and animal rabies. Dog rabies cases were analyzed using spatio-temporal scan statistics. The reproductive number (Rt) was estimated for the identified disease clusters. A phylogenetic tree was constructed based on the genome sequences of rabies viruses isolated from dogs, jackals, and an African civet, and Bayesian evolutionary analysis using a strict time clock model. Several ecological and socio-economic variables associated with dog rabies were modeled using univariate analyses with zero-inflated negative binomial regression and multivariable spatial analyses using the integrated nested Laplace approximation for two time periods: 1998– 2002 and 2008–2012. RESULTS : Human rabies cases increased in 2006 following an increase in dog rabies cases; however, the human cases declined in the next year while dog rabies cases fluctuated. Ten disease clusters of dog rabies were identified, and utilizing the phylogenetic tree, the dynamics of animal rabies over 20 years was elucidated. In 2006, a virus strain that re-emerged in eastern Limpopo Province caused the large and persistent dog rabies outbreaks in Limpopo and Mpumalanga Provinces. Several clusters included a rabies virus variant maintained in jackals in Limpopo Province, and the other variant in dogs widely distributed. The widely distributed variant maintained in jackal populations in North-West Province caused an outbreak in dogs in 2014. The Rt was high when the disease clusters were associated with either multiple virus strains or multiple animal species. High-risk areas included Limpopo and Mpumalanga Provinces characterized by woodlands and high temperatures and precipitation. CONCLUSION : Canine rabies was maintained mainly in dog populations but was also associated with jackal species. Rural communities in Limpopo and Mpumalanga Provinces were at high risk of canine rabies originating from dogs.The 2019 Japan Society for the Promotion of Science (JSPS) and National Research Foundation (NRF) of South Africa bilateral exchange program grant.https://journals.plos.org/plosntdsdm2022Geography, Geoinformatics and MeteorologyVeterinary Tropical Disease

Mokola Virus in Domestic Mammals, South Africa

We recently identified 2 Mokola viruses from domestic mammals (a dog and a cat) in South Africa. These cases occurred 8 years after the last reported case of infection with this virus. Our findings emphasize the endemicity of rabies-related lyssaviruses in South Africa and the need to better understand the epidemiology of Mokola viruses

Engineering, expression in transgenic plants and characterisation of e559, a rabies virus-neutralising monoclonal antibody.

Rabies post-exposure prophylaxis (PEP) currently comprises administration of rabies vaccine together with rabies immunoglobulin (RIG) of either equine or human origin. In the developing world, RIG preparations are expensive, often in short supply, and of variable efficacy. Therefore, we are seeking to develop a monoclonal antibody cocktail to replace RIG. Here, we describe the cloning, engineering and production in plants of a candidate monoclonal antibody (E559) for inclusion in such a cocktail. The murine constant domains of E559 were replaced with human IgG1κ constant domains and the resulting chimeric mouse-human genes were cloned into plant expression vectors for stable nuclear transformation of Nicotiana tabacum. The plant-expressed, chimeric antibody was purified and biochemically characterized, was demonstrated to neutralize rabies virus in a fluorescent antibody virus neutralization assay, and conferred protection in a hamster challenge model

Exploiting Pan Influenza A and Pan Influenza B Pseudotype Libraries for Efficient Vaccine Antigen Selection.

We developed an influenza hemagglutinin (HA) pseudotype library encompassing Influenza A subtypes HA1-18 and Influenza B subtypes (both lineages) to be employed in influenza pseudotype microneutralization (pMN) assays. The pMN is highly sensitive and specific for detecting virus-specific neutralizing antibodies against influenza viruses and can be used to assess antibody functionality in vitro. Here we show the production of these viral HA pseudotypes and their employment as substitutes for wildtype viruses in influenza neutralization assays. We demonstrate their utility in detecting serum responses to vaccination with the ability to evaluate cross-subtype neutralizing responses elicited by specific vaccinating antigens. Our findings may inform further preclinical studies involving immunization dosing regimens in mice and may help in the creation and selection of better antigens for vaccine design. These HA pseudotypes can be harnessed to meet strategic objectives that contribute to the strengthening of global influenza surveillance, expansion of seasonal influenza prevention and control policies, and strengthening pandemic preparedness and response