Rabies re-examined

A persona-based exploration of rabies post-exposure prophylaxis seeking behavior and its implication for communication strategic planning: Evidence from Thailand

Rabies is a lethal zoonotic illness that claims over 59,000 lives annually. However, this fatality can be avoided by postexposure prophylaxis (PEP). This study aimed to identify and characterize different personas of individuals regarding their PEP-seeking behavior and develop tailored communication strategies to encourage PEP adoption among these distinct groups effectively. We categorized our subjects, residing in two districts of Chonburi province, Thailand, into three groups: (i) individuals with a history of dog bites who underwent PEP; (ii) individuals bitten by dogs who did not receive PEP; and (iii) individuals who had never been bitten. Subsequently, we employed an empathy map, a visual method, and a customer journey map to better understand the participants' experiences and perceptions. A total of 38 individuals were interviewed. We categorized the participants into three distinct personas: positive, neutral, and negative trends. Individuals classified within the positive trend strongly advocate for seeking rabies vaccines in the event of a dog bite. Meanwhile, individuals who have a neutral inclination are more likely to contemplate getting vaccinated following a dog bite, particularly if the injury is substantial. Those with a negative trend demonstrate a notable lack of attention or concern toward preventing rabies. A lack of attention to the potential severity of the issue characterizes their attitude. Notably, nearly half (44.74 %; 17/38) of the individuals involved in the study indicated utilizing interpersonal communication, followed by digital platforms (42.11 %; 16/38) and traditional communication channels (10.52 %; 5/38). Tailoring communication modalities to suit each specific group is crucial for effective outreach.

First Report of Paralytic Rabies in a Lowland Tapir (Tapirus terrestris) in Argentina

As a significant zoonotic disease, rabies poses substantial economic challenges for the livestock sector, highlighting the need for effective wildlife monitoring as part of a One Health approach. This study documents the first case of paralytic rabies in a lowland tapir (Tapirus terrestris) at the Guaycolec Wildlife Station in Formosa, Argentina. The 12-year-old male tapir exhibited neurological symptoms, including limb paralysis and dysphagia, leading to its death. The rabies virus was confirmed through direct immunofluorescence, virus isolation in BHK-21 cells, and molecular diagnostics via real-time RT-PCR and conventional PCR. Antigenic variant 3, associated with Desmodus rotundus, was identified. Histopathological examination revealed non-suppurative encephalitis with lymphocytic perivascular cuffs, neuronal vacuolization, and acidophilic intracytoplasmic inclusion bodies in the grey matter. This case underscores the importance of expanded surveillance for non-traditional hosts, as it demonstrates the potential for rabies transmission in changing environments. The findings highlight the need to maintain epidemiological surveillance systems at the wildlife-livestock-human interface and to develop targeted control strategies to mitigate the spread of rabies, particularly in areas where vampire bat populations are subject to anthropogenic pressures. Comprehensive monitoring and early detection are essential for effective rabies management in both wildlife and urban contexts.

A comparative analysis of the dendritic cell response upon exposure to different rabies virus strains

Rabies is a viral zoonotic disease that causes over 60,000 human deaths annually worldwide. Natural infections lack a virus-specific immune response, leading to a near 100% fatality rate unless immediately treated. Rabies virus (RABV) is typically transmitted through bites from rabid dogs or other carnivores to humans and may initially interact with innate immune cells such as dendritic cells at the site of infection. This study investigates the in vitro response of human monocyte-derived dendritic cells (moDCs) exposed to two pathogenic RABV strains-silver-haired bat rabies virus (SHBRV) and dog-related rabies virus (dogRV)-and an attenuated vaccine strain (SAD P5). MoDCs were susceptible only to high doses of SHBRV and SAD P5, resulting in a more mature and migratory phenotype within the infected moDC populations. No infection was observed in moDCs exposed to dogRV. In co-culture with T cells, the presence of RABV-exposed moDCs, regardless of the strain, did not enhance T cell activation. Additionally, RABV exposure did not hinder LPS-induced moDC maturation; instead, high doses of SHBRV and SAD P5 even boosted activation levels. Overall, the findings suggest varied capabilities of RABV strains to infect and activate moDCs in vitro. However, exposure to any RABV strain did not provoke a clear antiviral state or suppression of moDC responsiveness. This lack of activation may contribute to the absence of an effective adaptive immune response in natural RABV infections.

Dog owners' intention to control rabies and their willingness to pay for rabies vaccine in Northwestern Ethiopia

Rabies is a viral disease that affects both animals and humans. Effectiveness of a rabies control measures depends on collaboration of dog owners. This study was conducted in North West Ethiopia to understand the intention and willingness to pay (WTP) of dog owners related to rabies control and factors affecting rabies control measures. Data was collected from 423 randomly selected dog owners in four Gondar zones, North West Ethiopia. The theory of planned behavior was used to explore the intention of dog owners towards implementing rabies control measures. Contingent evaluation method was used to evaluate WTP for rabies vaccine. Logistic regression analysis was used to test association with factors. Large majority of dog owners had positive intention to control rabies by vaccination of dogs (97% free of charge, 93% with fair price) and 94% by leashing. Majority of dog owners had a positive attitude (AT), positive subjective norms (SN) and positive perceived behavioral control (PBC) towards controlling rabies. Dog owners' AT and SN were positively associated with intention to vaccinate dogs. Male dog owners and dog owners belonging to lower age groups had significantly higher AT towards leashing dogs. Sixty two percent of dog owners were WTP for the suggested price bid amounts; but, in general, their number decreased when price of the vaccine increased. The mean WTP for rabies vaccine was 59.25 Ethiopian Birr (1.14 USD) per year. Monthly income was associated (P < 0.05) with WTP for rabies vaccine. Dog owners who had higher income had higher odds but those who did not vaccinate their dogs in the last two years had lower odds of WTP for rabies vaccine. Intervention directed at changing AT and SN is important to increase intention of dog owners; nevertheless subsidizing rabies vaccine increase dog owners participation in dogs vaccination campaign.

Infection and Prevention of Rabies Viruses

Rabies is a fatal zoonotic disease and causes about 59,000 human deaths globally every year. Especially, its mortality is almost 100% in cases where the rabies virus has transmitted to the central nervous system. The special virus life cycle and pathogenic mechanism make it difficult for the host immune system to combat rabies viruses. Vaccination including pre-exposure and post-exposure prophylaxis is an effective strategy for rabies prevention. The pre-exposure vaccination is mainly applied for animals and the post-exposure vaccination is the most application for humans. Although rabies vaccines are widely used and seem to be safe and effective, there are some disadvantages, limitations, or challenges affecting vaccine promotion and distribution. Therefore, more effective, convenient, safer, and cheaper rabies vaccines have been developed or are being developed. The development of novel human rabies vaccine is mainly focusing on vaccines based on a purified Vero cell-cultured freeze-dried rabies vaccine (PVRV). PVRV has been demonstrated to be promising to make the rabies vaccine more effective and secure in animal studies or clinical trials. Moreover, mRNA-based vaccines have been shown to have the potential to enhance the safety and efficacy of rabies vaccines for both animal and human uses.

The Role of Skunks in the Epidemiology of Rabies in the State of Yucatan from 2000 to 2022: Current Perspectives and Future Research Directions

In 2019, the World Health Organization (WHO) and the Pan American Health Organization (PAHO) bestowed upon Mexico the status of a country free from canine-transmitted human rabies; however, the lingering public health challenge in the nation continues to be the sylvatic cycle of rabies. In Mexico, skunks play a significant role as reservoirs for four antigenic variants of the rabies virus. Nonetheless, up to this point, the specific skunk species involved in this cycle had not been accurately established. This study (2002-2022) aims to identify the taxonomy of skunk specimens diagnosed as rabies-positive in the state of Yucatan, in order to determine the species that serves as the reservoir for the Yucatan sylvatic lineage of rabies. This was achieved through the sequencing of an approximately 680 bp fragment of the mitochondrial gene cytochrome B. All samples belong to the species Spilogale angustifrons yucatanensis. This discovery offers valuable information for understanding and managing the wildlife rabies cycle in Mexico. It also contributes to an improved understanding of the taxonomy within the genus Spilogale.

Possible Factors Concerning the Crossing of Formosan Ferret-Badger Rabies over the Daan River in Miaoli County, Taiwan

The first detection of Formosan ferret-badger (FFB) rabies on the main island of Taiwan occurred in July 2013. National surveillance reports indicated that prior to 2023, rabies outbreaks were limited to the southern region of the Daan River, which was considered a natural barrier preventing the spread northwards. However, in 2023, four new cases of rabid FFBs emerged in Miaoli County, located north of the Daan River, suggesting that the epizootic had crossed the river. Several factors may have contributed to the ability of reservoir FFBs to cross over the Daan River. Firstly, there was a decrease in rainfall in the upstream area of the Daan River in 2023. Secondly, the construction of the Shilin Weir by the Taiwan Power Company in the upstream area of the Daan River aimed to prioritize water diversion for hydropower generation while ensuring domestic water supply for Miaoli County and Taichung City. Lastly, there was an unusual increase in the number of roadkill FFBs during the rainy season of 2023. The decreased rainfall in FFB habitats in the mountains and the near-dry condition of the upstream Daan River caused by the Shilin Weir in 2023, allowing FFBs to easily cross the Daan River into Miaoli County. The evidence of unusually increased FFB activity in 2023 supports the speculation that FFBs crossed the Daan River, introducing FFB rabies into Miaoli County.

The Deadly Details: How Clear and Complete Are Publicly Available Sources of Human Rabies Information?

Human rabies is preventable but almost always fatal once symptoms appear, causing 59,000 global deaths each year. Limited awareness and inconsistent access to post-exposure prophylaxis hinder prevention efforts. To identify gaps and opportunities for improvement in online rabies information, we assessed the readability, understandability, actionability, and completeness of online public rabies resources from government and health agencies in Australia and similar countries, with the aim of identifying gaps and opportunities for improvement. We identified materials via Google and public health agency websites, assessing readability using the Simple Measure of Gobbledygook (SMOG) index and understandability and actionability with the Patient Education Materials Tool for Print materials (PEMAT-P). Completeness was assessed using a framework focused on general and vaccine-specific rabies information. An analysis of 22 resources found a median readability of grade 13 (range: 10-15), with a mean understandability of 66% and mean actionability of 60%; both below recommended thresholds. Mean completeness was 79% for general rabies information and 36% for vaccine-specific information. Visual aids were under-utilised, and critical vaccine-specific information was often lacking. These findings highlight significant barriers in rabies information for the public, with most resources requiring a high literacy level and lacking adequate understandability and actionability. Improving readability, adding visual aids, and enhancing vaccine-related content could improve accessibility and support wider prevention efforts.

Incidence of suspected human rabies virus exposure and associated risk factors in Ethiopia: systematic review and meta-analysis

BACKGROUND

Despite the World Health Organization's 2030 goal of zero deaths, rabies disproportionately affects Asia and Africa, causing 55,000 deaths and 8.6 billion monetary losses annually. In Ethiopia, dogs are the primary cause of human rabies virus exposure due to their close interaction with humans and other domestic animals. The results of previous studies on the incidence of suspected human rabies virus exposure were inconsistent and inadequate. This study aimed to measure the pooled incidence of suspected human rabies virus exposure and associated risk factors in Ethiopia.

METHODS

Published articles without publication date/year restriction were investigated using the guideline Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We searched PubMed, EMBASE, Science Direct, Google Scholar, and African Journals Online databases. Two independent authors extracted the required data. This meta-analysis was carried out using the program Stata Version 17, the DerSimonian-Laird method, and a random-effects model. The I2 and Cochrane Q test statistics were used to determine the studies' heterogeneity. Egger's test and funnel plots were used to assess publication bias. Data were displayed using forest plots of incidence and risk ratio (RR) with a 95% confidence interval.

RESULTS

Eight articles with 18 data points and 116,484 sample sizes were included. The pooled incidence rate was 54.03 (95% CI: 43.92-64.13) per 100,000 population. The highest, 107.32 (95% CI: 80.20-134.45) per 100,000 population, and the lowest, 4.49 (95% CI: 2.00-6.97) per 100,000 incidence rate, were observed in the Oromia and Amhara regions, respectively. Sex was significantly associated with the incidence of human rabies exposure. Being male was (RR = 1.67, 95% CI; 1.53-1.81) times more likely to be exposed to the human rabies virus than those who were females.

CONCLUSION

The estimated incidence was found to vary by location and was reported as high. One important contributing factor was sex. Human rabies virus exposure prevention, such as dog vaccination, public awareness, and an epidemiological surveillance system, should be improved.

Assessment of knowledge, attitude and practice towards rabies and associated factors among household heads in Welkait district, Ethiopia

BACKGROUND

Rabies is an important worldwide viral zoonotic disease with a high fatality rate and substantial socioeconomic losses. There is limited information about the community's knowledge, attitude and practice towards rabies disease in the study area. Therefore, this study was intended to assess knowledge, attitude, and practice (KAP) and associated factors towards rabies among the community in Welkait district, Northwest Ethiopia.

METHODS

A community-based cross-sectional study was conducted in Welkait district from January to April 2021 with a total of 384 study participants. The study sites were randomly selected using the lottery method. A simple random sampling technique was employed to select households. The data was obtained using structured questionnaires. Descriptive statistics and Pearson's Chi-square (X2) analysis were used to report the association between variables. P < 0.05 was considered statistically significant at 95% CI.

RESULTS

Out of 384 study participants, 51.6% (n = 198) had a good level of knowledge, attitude, and practice (KAP) about rabies disease. Among study participants, only 24.2% (n = 93) of respondents had good knowledge of post-exposure prophylaxis. However, most of the study participants 68.5% (n = 263) had good attitudes towards anti-rabies vaccine for humans. Among the d factors assessed, sex (P = 0.001), level of education (p < 0.000) and residence (P = 0.017) had statistically significant associations with knowledge, attitude and practice (KAP) of study participants about rabies disease.

CONCLUSIONS

This study indicated knowledge, attitude, and practice gaps among the community towards rabies disease. Therefore, Community public health education should focus on creating attitudes and practices that effectively reduce the rabies burden in the study area.

Environmental stressors and zoonoses in the Arctic: Learning from the past to prepare for the future

The risk of zoonotic disease transmission from animals to humans is elevated for people in close contact with domestic and wild animals. About three-quarters of all known human infectious diseases are zoonotic, and potential health impacts of these diseases are higher where infectious disease surveillance and access to health care and public health services are limited. This is especially the case for remote circumarctic regions, where drivers for endemic, emerging, and re-emerging zoonotic diseases include anthropogenic influences, such as pollution by long-range transport of industrial chemicals, climate change, loss of biodiversity and ecosystem alterations. In addition to these, indirect effects including natural changes in food web dynamics, appearance of invasive species and thawing permafrost also affect the risk of zoonotic disease spill-over. In other words, the Arctic represents a changing world where pollution, loss of biodiversity and habitat, and maritime activity are likely driving forward occurrence of infectious diseases. As a broad international consortium with a wide range of expertise, we here describe a selection of case studies highlighting the importance of a One Health approach to zoonoses in the circumarctic, encompassing human health, animal health, and environmental health aspects. The cases highlight critical gaps in monitoring and current knowledge, focusing on environmental stressors and lifestyle factors, and they are examples of current occurrences in the Arctic that inform on critically needed actions to prepare us for the future. Through these presentations, we recommend measures to enhance awareness and management of existing and emerging zoonoses with epidemic and pandemic potential while also focusing on the impacts of various environmental stressors and lifestyle factors on zoonoses in the Arctic.

Adapted Milwaukee protocol for rabies treatment in a Brazilian indigenous child: case report

BACKGROUND

This case report describes the treatment of a 12-year-old indigenous Brazilian girl from the Maxakali group with rabies using the adapted Milwaukee Protocol.

CASE PRESENTATION

The patient suffered a superficial bat bite on her right elbow, reported on April 5, 2022. Despite receiving immunoglobulin, a vaccine, and antiviral medications such as amantadine and sapropterin, the patient succumbed to the disease 25 days after hospital admission. The report highlights the inherent challenges in treating rabies due to the virus's neurotropic nature and the difficulties in delivering antiviral drugs to the central nervous system. The case underscores the need for early antiviral intervention and calls for more studies to validate and improve treatment protocols for rabies in vulnerable populations, particularly those with genetic and immunological susceptibilities like the Maxakali indigenous group.

CONCLUSION

The findings suggest that while the Milwaukee Protocol offers some hope, significant obstacles remain in achieving successful outcomes in rabies cases.

Climate change linked to vampire bat expansion and rabies virus spillover

Bat-borne pathogens are a threat to global health and in recent history have had major impacts on human morbidity and mortality. Examples include diseases such as rabies, Nipah virus encephalitis, and severe acute respiratory syndrome (SARS). Climate change may exacerbate the emergence of bat-borne pathogens by affecting the ecology of bats in tropical ecosystems. Here, we report the impacts of climate change on the distributional ecology of the common vampire bat Desmodus rotundus across the last century. Our retrospective analysis revealed a positive relationship between changes in climate and the northern expansion of the distribution of D. rotundus in North America. Furthermore, we also found a reduction in the standard deviation of temperatures at D. rotundus capture locations during the last century, expressed as more consistent, less-seasonal climate in recent years. These results elucidate an association between D. rotundus range expansion and a continental-level rise in rabies virus spill-over transmission from D. rotundus to cattle in the last 50 years of the 120-year study period. This correlative study, based on field observations, offers empirical evidence supporting previous statistical and mathematical simulation-based studies reporting a likely increase of bat-borne diseases in response to climate change. We conclude that the D. rotundus rabies system exemplifies the consequences of climate change augmentation at the wildlife-livestock-human interface, demonstrating how global change acts upon these complex and interconnected systems to drive increased disease emergence.

Safety and efficacy assessment of an mRNA rabies vaccine in dogs, rodents, and cynomolgus macaques

Rabies is a lethal disease caused by the rabies virus (RABV), which causes acute neurological infections in mammals, including human beings. We previously reported that an mRNA vaccine (LVRNA001) encoding the rabies virus's glycoprotein induced strong protective immune responses to rabies in mice and dogs. Here, we further evaluate the safety of LVRNA001. First, we performed a confirmative efficacy study in dogs, which showed that LVRNA001 fully protected the animals from the virus, both pre- and post-infection. Moreover, using pre- and post-exposure prophylaxis murine models, we showed that LVRNA001, built from the CTN-1 strain, was able to protect against various representative RABV strains from the China I-VII clades. To evaluate the safety of the vaccine, chronic and reproductive toxicity studies were performed with cynomolgus macaques and rats, respectively. In a repeated-dose chronic toxicity study, vaccinated monkeys displayed no significant alterations in body weight, temperature, or hematological and biochemical markers. Lymphocyte subset measurement and histopathological examination showed that no toxicity was associated with the vaccine. The immunogenicity study in cynomolgus macaques demonstrated that LVRNA001 promoted the generation of neutralizing antibodies and Th1-biased immune response. Evaluation of reproductive toxicity in rats revealed that administration of LVRNA001 had no significant effects on fertility, maternal performance, reproductive processes, and postnatal outcomes. In conclusion, LVRNA001 can provide efficient protection against rabies virus infection in dogs and mice, and toxicity studies showed no significant vaccine-related adverse effects, suggesting that LVRNA001 is a promising and safe vaccine candidate for rabies prophylaxis and therapy.

Optimizing the location of vaccination sites to stop a zoonotic epidemic

Mass vaccinations are crucial public health interventions for curbing infectious diseases. Canine rabies control relies on mass dog vaccination campaigns (MDVCs) that are held annually across the globe. Dog owners must bring their pets to fixed vaccination sites, but sometimes target coverage is not achieved due to low participation. Travel distance to vaccination sites is an important barrier to participation. We aimed to increase MDVC participation in silico by optimally placing fixed-point vaccination locations. We quantified participation probability based on walking distance to the nearest vaccination site using regression models fit to participation data collected over 4 years. We used computational recursive interchange techniques to optimally place fixed-point vaccination sites and compared predicted participation with these optimally placed vaccination sites to actual locations used in previous campaigns. Algorithms that minimized average walking distance or maximized expected participation provided the best solutions. Optimal vaccination placement is expected to increase participation by 7% and improve spatial evenness of coverage, resulting in fewer under-vaccinated pockets. However, unevenness in workload across sites remained. Our data-driven algorithm optimally places limited resources to increase overall vaccination participation and equity. Field evaluations are essential to assess effectiveness and evaluate potentially longer waiting queues resulting from increased participation.

[Rabies: Epidemiological update and pre- and post-exposure management]

Rabies is a deadly neurotropic viral infection but is preventable through vaccination. Its impact on human and animal health is often devastating. Despite advances in research and control of this disease, along with an effective vaccine, rabies continues to be a lingering threat in many parts of the world. Its high incidence reinforces the constant need to address it with scientific and public health measures. In this review article, we will explore the most important characteristics of the disease, its distribution, symptoms, prevention methods, and the global efforts that have been made to eradicate this deadly disease. The most recent research and advancements in the field of rabies will also be discussed in an effort to understand and combat this deadly disease more effectively.

Rabies Vaccine for Prophylaxis and Treatment of Rabies: A Narrative Review

Rabies, a millennia-old viral infection transmitted through animal bites, poses a lethal threat to humans, with a historic fatality rate of 100% if left untreated. Louis Pasteur's introduction of the rabies vaccine in 1885 marked a turning point in the battle against rabies, preventing numerous cases. The purpose of this paper is to review the historical development, current challenges, and future prospects of rabies vaccination and treatment, with emphasis on the importance of continued research and collaborative efforts in the quest to eradicate this deadly infection. Historical vaccine development progressed from inactivated to live-attenuated forms, with modern recombinant techniques showing promise. The preventive measures at present primarily involve vaccination, but challenges persist, such as differing safety profiles and immunogenicity among vaccine types. Pre-exposure prophylaxis with a three-dose vaccine series is crucial, especially in high-risk scenarios. Post-exposure prophylaxis combines human rabies immunoglobulin and inactivated rabies virus vaccine. The quest for the next generation of vaccines explores genetically modified and viral vector-based approaches; emerging treatments include gene therapy, virus-like particles, and monoclonal antibodies, offering hope for improved outcomes. Economic barriers to post-exposure prophylaxis, limited education, and awareness challenge rabies control. Cost-effective solutions and comprehensive awareness campaigns are vital for the successful eradication of rabies. More research and collaborative endeavors remain pivotal in the ongoing journey to eradicate rabies, one of the deadliest infectious diseases known to humans, if not met with prophylactic measures.

Mathematical model of rabies vaccination in the United States

Rabies is one of the oldest viral diseases and it has been present on every continent except Antarctica. Within the U.S. human rabies cases are quite rare. In the eastern USA, raccoons are the main reservoir hosts and pet vaccination serves as an important barrier against human rabies exposure. In this paper, we develop a compartmental model for rabies transmission amongst raccoons and domestic pets. We find the disease-free equilibria, reproduction numbers for the raccoons and domestic pets. We also determine the vaccination coverage/rates, both for raccoons and pets, needed to achieve the elimination of rabies.

The human alpha7 nicotinic acetylcholine receptor is a host target for the rabies virus glycoprotein

The rabies virus enters the nervous system by interacting with several molecular targets on host cells to modify behavior and trigger receptor-mediated endocytosis of the virion by poorly understood mechanisms. The rabies virus glycoprotein (RVG) interacts with the muscle acetylcholine receptor and the neuronal α4β2 subtype of the nicotinic acetylcholine receptor (nAChR) family by the putative neurotoxin-like motif. Given that the neurotoxin-like motif is highly homologous to the α7 nAChR subtype selective snake toxin α-bungarotoxin (αBTX), other nAChR subtypes are likely involved. The purpose of this study is to determine the activity of the RVG neurotoxin-like motif on nAChR subtypes that are expressed in brain regions involved in rabid animal behavior. nAChRs were expressed in Xenopus laevis oocytes, and two-electrode voltage clamp electrophysiology was used to collect concentration-response data to measure the functional effects. The RVG peptide preferentially and completely inhibits α7 nAChR ACh-induced currents by a competitive antagonist mechanism. Tested heteromeric nAChRs are also inhibited, but to a lesser extent than the α7 subtype. Residues of the RVG peptide with high sequence homology to αBTX and other neurotoxins were substituted with alanine. Altered RVG neurotoxin-like peptides showed that residues phenylalanine 192, arginine 196, and arginine 199 are important determinants of RVG peptide apparent potency on α7 nAChRs, while serine 195 is not. The evaluation of the rabies ectodomain reaffirmed the observations made with the RVG peptide, illustrating a significant inhibitory impact on α7 nAChR with potency in the nanomolar range. In a mammalian cell culture model of neurons, we confirm that the RVG peptide binds preferentially to cells expressing the α7 nAChR. Defining the activity of the RVG peptide on nAChRs expands our understanding of basic mechanisms in host-pathogen interactions that result in neurological disorders.

Preclinical animal models to evaluate therapeutic antiviral antibodies

Despite the availability of effective preventative vaccines and potent small-molecule antiviral drugs, effective non-toxic prophylactic and therapeutic measures are still lacking for many viruses. The use of monoclonal and polyclonal antibodies in an antiviral context could fill this gap and provide effective virus-specific medical interventions. In order to develop these therapeutic antibodies, preclinical animal models are of utmost importance. Due to the variability in viral pathogenesis, immunity and overall characteristics, the most representative animal model for human viral infection differs between virus species. Therefore, throughout the years researchers sought to find the ideal preclinical animal model for each virus. The most used animal models in preclinical research include rodents (mice, ferrets, …) and non-human primates (macaques, chimpanzee, ….). Currently, antibodies are tested for antiviral efficacy against a variety of viruses including different hepatitis viruses, human immunodeficiency virus (HIV), influenza viruses, respiratory syncytial virus (RSV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and rabies virus. This review provides an overview of the current knowledge about the preclinical animal models that are used for the evaluation of therapeutic antibodies for the abovementioned viruses.

Bovine rabies cases in Ecuador: a retrospective cross-sectional observational study (2007 to 2020)

The hematophagous bats are usually the main reservoir of sylvatic rabies, being one of the most important viral zoonoses affecting humans and livestock in Latin America. Despite the most countries have already studied spatio-temporal distribution of bovine rabies, however, in Ecuador, little has been reported about the state of rabies in the country. Aiming to this objective, a descriptive observational study was realized from 2007 to 2020 based on the formal reports by WAHI-OIE and surveillance of bovine rabies retrieved from its official website. During the study period in Ecuador, some 895 cases of rabies were confirmed in cattle. In addition, in the total of bovine rabies cases seen in Andean and Coast regions (185 effected bovines), Loja and Esmeraldas had 95 (6.16% cases per 10,000 animals) and 51 (1.7% cases per 10,000 animals), respectively. Furthermore, the Amazon region indicated higher rabies cases in cattle than to the observed in other regions (710 rabies cases) while it was highly fluctuating with respect to the years (9.74 to 42.82% cases per 10,000 animals). However, Zamora (292 rabies cases), Orellana (115 rabies cases) and Sucumbíos (113 rabies cases) yielded the highest incidence rates than other provinces (9 to 42% cases per 10,000 animals). Based on this evidence, it has been fundamental to assess the current national program for preventing and control of the sylvatic rabies, being also necessary to include concept of the ecology of the vampire bat. Regardless of these results, vaccination is vital for control programs to prevent rabies in livestock and need to be widely increased for limiting their geographic and temporal spread.

MA, Tovar-Rosero YY, Oñate AA, O'Ryan M. Two centuries of vaccination: historical and conceptual approach and future perspectives

Over the past two centuries, vaccines have been critical for the prevention of infectious diseases and are considered milestones in the medical and public health history. The World Health Organization estimates that vaccination currently prevents approximately 3.5-5 million deaths annually, attributed to diseases such as diphtheria, tetanus, pertussis, influenza, and measles. Vaccination has been instrumental in eradicating important pathogens, including the smallpox virus and wild poliovirus types 2 and 3. This narrative review offers a detailed journey through the history and advancements in vaccinology, tailored for healthcare workers. It traces pivotal milestones, beginning with the variolation practices in the early 17th century, the development of the first smallpox vaccine, and the continuous evolution and innovation in vaccine development up to the present day. We also briefly review immunological principles underlying vaccination, as well as the main vaccine types, with a special mention of the recently introduced mRNA vaccine technology. Additionally, we discuss the broad benefits of vaccines, including their role in reducing morbidity and mortality, and in fostering socioeconomic development in communities. Finally, we address the issue of vaccine hesitancy and discuss effective strategies to promote vaccine acceptance. Research, collaboration, and the widespread acceptance and use of vaccines are imperative for the continued success of vaccination programs in controlling and ultimately eradicating infectious diseases.

Assessing the Efficiency of Local Rabies Vaccination Strategies for Raccoons (Procyon lotor) in an Urban Setting

Raccoon rabies virus (RRV) has been managed using multiple vaccination strategies, including oral rabies vaccination and trap-vaccinate-release (TVR). Identifying a rabies vaccination strategy for an area is a nontrivial task. Vaccination strategies differ in the amount of effort and monetary costs required to achieve a particular level of vaccine seroprevalence (efficiency). Simulating host movement relative to different vaccination strategies in silico can provide a useful tool for exploring the efficiency of different vaccination strategies. We refined a previously developed individual-based model of raccoon movement to evaluate vaccination strategies for urban Hamilton, Ontario, Canada. We combined different oral rabies vaccination baiting (hand baiting, helicopter, and bait stations) with TVR strategies and used GPS data to parameterize and simulate raccoon movement in Hamilton. We developed a total of 560 vaccination strategies, in consultation with the Ontario Ministry of Natural Resources and Forestry, for RRV control in Hamilton. We documented the monetary costs of each vaccination strategy and estimated the population seroprevalence. Intervention costs and seroprevalence estimates were used to calculate the efficiency of each strategy to meet targets set for the purpose of RRV control. Estimated seroprevalence across different strategies varied widely, ranging from less than 5% to more than 70%. Increasing bait densities (distributed using by hand or helicopter) led to negligible increase in seroprevalence. Helicopter baiting was the most efficient and TVR was the least efficient, but helicopter-based strategies led to lower levels of seroprevalence (6-12%) than did TVR-based strategies (17-70%). Our simulations indicated that a mixed strategy including at least some TVR may be the most efficient strategy for a local urban RRV control program when seroprevalence levels >30% may be required. Our simulations provide information regarding the efficiency of different vaccination strategies for raccoon populations, to guide local RRV control in urban settings.

Evaluation of the effect of sample suspension concentration and viral load on the outcome of the rabies tissue culture infection test

In this study, we examined various brain suspension concentrations and viral loads in Neuro-2a cell cultures using 20 rabies-positive bovine samples. The reproducibility of results varied: 65% showed consistent outcomes across all concentrations, while 35% disagreed in at least one. Viral titers ranged from less than 25 × 101 to 25 × 103.50 TCID50/mL, with 20% below 25 × 101 TCID50/mL. Concentrations between 5% and 20% yielded over 90% agreement in positive results, but at 30%, agreement dropped from 85% to 50%. Cell confluence was successfully maintained at 5%, 10%, and 20%, while concentrations of 30% and above led to confluence loss. Low viral loads also negatively impacted reproducibility. These results suggest that sample concentration has a direct influence on preservation of cell confluence and that low viral loads may influence the reproducibility of the rabies tissue culture infection test (RTCIT).

Ante-mortem and Post-mortem Diagnosis Modalities and Phylogenetic Analysis of Rabies Virus in Domestic and Wild Animals of Gujarat, India

In the present study, total of 32 ante-mortem (AM) samples (saliva = 18 and corneal smears = 14) from six animal species (cattle = 5; camel = 1; goat = 1; horse = 1; buffalo = 4; dog = 6) and 28 post-mortem (PM) samples of domestic (cattle = 6; camel = 1; goat = 1; buffalo = 5; dog = 7) and wild animals (lion = 4, mongoose = 2; bear = 1; leopard = 1) were examined for rabies diagnosis in Gujarat, India. Direct fluorescent antibody test (dFAT) and reverse transcriptase polymerase chain reaction (RT-PCR) were applied on AM samples, whereas along with dFAT and RT-PCR, histopathological examination, immunohistochemistry (IHC) and real time PCR (qPCR) were used for PM diagnosis. Nucleotide sequencing of full nucleoprotein (N) and glycoprotein (G) genes were carried out upon representative amplicons. In AM examination, 7/18 saliva and 5/14 corneal impressions samples were found positive in dFAT and 8/18 saliva samples were found positive in RT-PCR. In PM examination, 14/28 samples showed positive results in dFAT and IHC with unusual large fluorescent foci in two samples. In histopathology, 11/28 samples showed appreciable lesion and Negri bodies were visible in 6 samples, only. Out of 23 brain samples examined. 12 samples were found positive in N gene RT-PCR and qPCR, and 10 samples in G gene RT-PCR. Phylogenetic analysis of N gene revealed that test isolates (except sample ID: lion-1; lion, Gir) form a close group with sequence ID, KM099393.1 (Mongoose, Hyderabad) and KF660246.1 (Water Buffalo, Hyderabad) which was far from some south Indian and Sri Lankan isolates but similar to Indian isolates from rest of India and neighboring countries. In G gene analysis, the test isolates form a close group with sequence ID, KP019943.1.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-023-01126-0.

No Evidence of Rabies Exposure in Wild Marmosets (Callithrix jacchus) of Northeast Brazil

Rabies transmitted by wildlife is the main source of human rabies mortality in Latin America and considered an emerging disease. The common marmoset Callithrix jacchus of Brazil is the only known primate reservoir of rabies worldwide. We tested whether alive free-ranging C. jacchus were exposed to rabies in four northeast states that have previously reported rabies-positive dead C. jacchus (Pernambuco and Bahia) or not (Paraíba and Rio Grande do Norte). Our results show no evidence of rabies antibodies or infection in the sampled C. jacchus, suggesting that apparently healthy marmosets are not widely exposed to rabies over their natural range.

Spatiotemporal patterns of rabid dogs and cats and the opinions of personnel responsible for disease control in Thailand

The aim of this study was to evaluate the patterns of rabies cases in dogs and cats in Thailand from 2013 to 2016 via spatiotemporal analysis. We also assessed the opinions of responsible district-level personnel regarding risk factors and control measures for rabies. Evaluation of rabies case patterns was based on secondary data from a national online database, and a structured questionnaire was used to obtain the opinions of district-level personnel. A total of 1202 cases (1202/13058, 9.21 %) of rabid dogs and cats were documented between 2013 and 2016, with the majority of cases involving dogs (1165/13058; 8.92 %). The spatiotemporal analysis indicated that most of the cases were recorded in central Thailand and that there was a general trend of an increase in rabies cases from the beginning of 2013 to the end of 2016. Month-by-month analysis for each year suggested that the number of rabies cases tended to increase over the course of the year in 2013 and 2016. Results from the autocorrelation indicated that the correlation coefficient tended to be similar in adjacent time lags. In terms of the opinion analysis, only one factor (i.e., the presence of a forest that served as a habitat for carrier animals in the district) was statistically significant (P < 0.05) in the final binary logistic regression model. The results of this study may facilitate planning for effective rabies control in Thailand.

What a Tick Can Tell a Doctor: Using the Human-Biting Tick in the Clinical Management of Tick-Borne Disease

With expanding concern about ticks, there is a general sense of uncertainty about the diagnosis and treatment of tick-borne diseases. The diagnosis process is often based on clinical judgment in conjunction with laboratory testing and can be pathogen specific. Treatments may require disease-dependent approaches, and co-infections complicate or increase the severity of the clinical picture. Measuring exposure indices in the tick has become popular among providers and their patients, though this practice is not universally understood, and certain public health agencies have voiced concerns regarding interpretation and rigor of testing. As many providers subscribe to or recommend these services to aid in pretest risk and exposure assessments, this work sought to clarify the role of pathogen testing human-biting ticks as a complement to the diagnostic pipeline and raises points that must be addressed through future research and interdisciplinary conversation. Future work is needed to develop quality control oversight for tick testing laboratories. Studies on the integration of tick testing with human cases to see how these services affect health outcomes are also needed. Alongside these, improvements in the quality and availability of diagnostics are of critical importance.

Parasite-mediated manipulation? Toxoplasma gondii infection increases risk behaviour towards culling in red deer

Parasites can modify host behaviour to increase their chances of survival and transmission. Toxoplasma gondii is a globally distributed protozoan whose ability to modify host behaviour is well known in taxa such as rats and humans. Less well known are the effects on the behaviour of wild species, with the exception of a few studies on primates and carnivores. Taking advantage of a culling activity conducted in Stelvio National Park (Italy), the serological status of T. gondii was studied in 260 individuals of red deer Cervus elaphus with respect to the risk of being culled. A temporal culling rank index was fitted as a response variable, and T. gondii serological status as the main explanatory variable in linear models, accounting for covariates such as sex, age, jaw length, bone marrow fat and culling location. The overall seroprevalence of T. gondii was 31.5%, and the selected models suggested that seropositive deer were culled earlier than seronegative ones, but this effect was only evident in females, in individuals with medium-good body condition, and in areas with greater human presence. Our results suggest that T. gondii may be involved in risk behaviour in large herbivores, supporting its role as a facilitator of predation risk.

How knowledgeable are people in Nepal about rabies?

Eliminating dog-mediated human rabies cases by 2030 is a collective global pledge. Rabies is a vaccine-preventable, zoonotic, and fatal viral disease tormenting human beings and animals for at least four thousand years. An average annual fatality of 59,000 people has been reported from rabies in more than 150 countries, including Nepal. Understanding people's knowledge towards rabies is paramount to preventing this disease. A cross-sectional study was conducted in three districts, namely, Siraha, Parsa, and Parasi in Nepal, from October to December 2021 to assess the level of public awareness of rabies. Information was obtained using a structured questionnaire among 308 household heads. Study findings show that some of the respondents were unfamiliar with the term 'rabies'. They knew major carriers or sources of rabies, but the majority of them (87.3%) did not know its causative agent. They had some idea of how rabies is transmitted from animals to humans, but they lacked a clear understanding of the fate of the animals and humans once affected cases are symptomatic. Only 35.1% of respondents knew that rabies pathogens attack and multiply in the brain tissues. Rabies vaccination in pets is critical for rabies eradication, yet only 26.3% of respondents were aware of the vaccination schedule. Nearly 90% of respondents thought post-exposure prophylaxis (PEP) to be effective immediately after a suspected animal bite. The findings show that there was a significant relationship between independent variables viz. pet ownership (X2 = 20.273, p < 0.001), level of education (X2 = 39.215, p < 0.001), household income (X2 = 13.574, p < 0.001), family size (X2 = 15.053, p < 0.001), main occupation (X2 = 11.618, p = 0.020), age (X2 = 6.982, p = 0.008) with dependent variable i. e., knowledge category (good and poor knowledge). Education to invoke awareness among rural people about rabies, its transmission and prevention, including making anti-rabies vaccines freely available, should be the priority for municipalities, public health and veterinary health authorities in the study districts and throughout the country.

Efficiency Comparative Approach of Plant-Produced Monoclonal Antibodies against Rabies Virus Infection

Rabies encephalitis is a fatal zoonotic viral disease caused by the neurotropic rabies virus. It remains a major public health concern as it causes almost 100% fatality and has no effective medication after the onset of the disease. However, this illness is preventable with the timely administration of effective post-exposure prophylaxis (PEP) consisting of the rabies vaccine and passive immune globulins (HRIG and ERIG). Recently, conventional PEP has been shown to have many limitations, resulting in little support for these expensive and heterologous globulins. Monoclonal antibody (mAb) production via recombinant technology in animal and human cell cultures, as well as a plant-based platform, was introduced to overcome the costly and high-tech constraints of former preparations. We used transient expression technology to produce two mAbs against the rabies virus in Nicotiana benthamiana and compared their viral neutralizing activity in vitro and in vivo. The expression levels of selective mAbs E559 and 62-71-3 in plants were estimated to be 17.3 mg/kg and 28.6 mg/kg in fresh weight, respectively. The plant-produced mAbs effectively neutralized the challenge virus CVS-11 strain in a cell-based RFFIT. In addition, the combination of these two mAbs in a cocktail protected hamsters from rabies virus infection more effectively than standard HRIG and ERIG. This study suggests that the plant-produced rabies antibody cocktail has promising potential as an alternative biological to polyclonal RIG in rabies PEP.

Comparison of Anti-rabies Virus Nucleoprotein IgY Prepared by DNA Immunization and Protein Immunization

Immunization of egg-laying hens with viral antigens efficiently produces large amounts of virus-specific IgY antibodies from egg yolks. A supply of practical and economical antibodies against the rabies virus is being desired worldwide. We immunized hens with the antigen gene DNA of the rabies virus, purified specific IgY antibodies from the egg yolk, and characterized the immuno-protein chemistry for use as a diagnosis. To prepare specific IgY antibodies against rabies virus nucleoprotein (RV-N) by DNA immunization, laying hens were pre-injected with λ-carrageenan or Freund's complete adjuvant to increase local immune activity (pre-immune stimulation), and then immunized with RV-N recombinant plasmid DNA. RV-N-specific IgY antibodies were prepared from egg yolks of immunized hens. For comparison, conventional protein antigen immunization was also used to induce the production of RV-N-specific IgY antibodies. Laying hens were immunized with an RV-N protein antigen and RV-N-specific IgY was purified from egg yolks. The binding activity against RV-N antigens was examined using IgY samples prepared by DNA (with pre-immune stimulation) and protein immunization. Immunohistochemical staining showed that IgY antibodies prepared by protein immunization strongly detected viral antigens in the brain sections of dogs infected with the virus, whereas IgY antibodies prepared by DNA immunization did not. Enzyme-linked immunosorbent assay was performed using a commercially available rabies vaccine (inactivated virus) treated with 10% formalin and heating (60°C, 30 min and 90°C, 5 min). IgY prepared by DNA immunization had weaker reactivity with denatured antigens and lower antigen concentrations than IgY prepared by protein immunization. These results suggest that it is necessary to develop a DNA immunization method for inducing IgY antibodies against the rabies virus that strongly bind to native and denatured antigens to prepare specific IgYs that can be used for antigen detection in clinical tests.

Low levels of genetic differentiation and structure in red fox populations in Eastern Canada and implications for Arctic fox rabies propagation potential

Rabies is a lethal zoonosis present in most parts of the world which can be transmitted to humans through the bite from an infected mammalian reservoir host. The Arctic rabies virus variant (ARVV) persists mainly in populations of Arctic foxes (Vulpes lagopus), and to a lesser extent in red fox populations (Vulpes vulpes). Red foxes are thought to be responsible for sporadic southward movement waves of the ARVV outside the enzootic area of northern Canada. In this study, we wanted to investigate whether red foxes displayed notable levels of genetic structure across the Quebec-Labrador Peninsula, which includes portions of the provinces of Quebec and Newfoundland-Labrador in Canada, and is a region with a history of southward ARVV movement waves. We combined two datasets that were collected and genotyped using different protocols, totalling 675 red fox individuals across the whole region and genotyped across 13 microsatellite markers. We found two genetic clusters across the region, reflecting a latitudinal gradient, and characterized by low genetic differentiation. We also observed weak but significant isolation by distance, which seems to be marginally more important for females than for males. These findings suggest a general lack of resistance to movement in red fox populations across the Quebec-Labrador Peninsula, regardless of sex. Implications of these findings include additional support for the hypothesis of long-distance southward ARVV propagation through its red fox reservoir host.

Developments in Rabies Vaccines: The Path Traversed from Pasteur to the Modern Era of Immunization

Rabies is a disease of antiquity and has a history spanning millennia ever since the first interactions between humans and dogs. The alarming fatalities caused by this disease have triggered rabies prevention strategies since the first century BC. There have been numerous attempts over the past 100 years to develop rabies vaccineswith the goal of preventing rabies in both humans and animals. Thepre-Pasteurian vaccinologists, paved the way for the actual history of rabies vaccines with the development of first generation vaccines. Further improvements for less reactive and more immunogenic vaccines have led to the expansion of embryo vaccines, tissue culture vaccines, cell culture vaccines, modified live vaccines, inactivated vaccines, and adjuvanted vaccines. The adventof recombinant technology and reverse genetics have given insight into the rabies viral genome and facilitated genome manipulations, which in turn led to the emergence of next-generation rabies vaccines, such as recombinant vaccines, viral vector vaccines, genetically modified vaccines, and nucleic acid vaccines. These vaccines were very helpful in overcoming the drawbacks of conventional rabies vaccines with increased immunogenicity and clinical efficacies. The path traversed in the development of rabies vaccines from Pasteur to the modern era vaccines, though, faced numerous challenges;these pioneering works have formed the cornerstone for the generation of thecurrent successful vaccines to prevent rabies. In the future, advancements in the scientific technologies and research focus will definitely lay the path for much more sophisticated vaccine candidates for rabies elimination.

Revealing the complexity of vampire bat rabies "spillover transmission"

BACKGROUND

The term virus 'spillover' embodies a highly complex phenomenon and is often used to refer to viral transmission from a primary reservoir host to a new, naïve yet susceptible and permissive host species. Spillover transmission can result in a virus becoming pathogenic, causing disease and death to the new host if successful infection and transmission takes place.

MAIN TEXT

The scientific literature across diverse disciplines has used the terms virus spillover, spillover transmission, cross-species transmission, and host shift almost indistinctly to imply the complex process of establishment of a virus from an original host (source/donor) to a naïve host (recipient), which have close or distant taxonomic or evolutionary ties. Spillover transmission may result in unsuccessful onward transmission, if the virus dies off before propagation. Alternatively, successful viral establishment in the new host can occur if subsequent secondary transmission among individuals of the same novel species and among other sympatric susceptible species occurred. As such, virus spillover transmission is a common yet highly complex phenomenon that encompasses multiple subtle stages that can be deconstructed to be studied separately to better understand the drivers of disease emergence. Rabies virus (RABV) is a well-documented viral pathogen which still inflicts heavy impact on humans, companion animals, wildlife, and livestock throughout Latin America due substantial spatial temporal and ecological-natural and expansional-overlap with several virus reservoir hosts. Thereby, the rabies disease system represents a robust avenue through which the drivers and uncertainties surrounding spillover transmission can be unravel at its different subtle stages to better understand how they may be affected by coarse, medium, and fine scale variables.

CONCLUSIONS

The continued study of viral spillover transmission necessitates the elucidation of its complexities to better assess the cross-scale impacts of ecological forces linked to the propensity of spillover success. Improving capacities to reconstruct and predict spillover transmission would prevent public health impacts on those most at risk populations across the globe.

Global burden of rabies in 204 countries and territories, from 1990 to 2019: results from the Global Burden of Disease Study 2019

OBJECTIVES

Rabies is an acute lethal infectious disease caused by a lyssavirus infection. In 2018, the World Health Organization proposed a global strategic plan to end human rabies deaths by 2030. However, systematic studies on the global rabies disease burden and epidemiological trends are scarce.

METHODS

We extracted the disease burden and epidemiological data of rabies worldwide in the preceding 30 years from the Global Burden of Disease Study 2019 and performed a comprehensive analysis.

RESULTS

In 2019, the incident cases of rabies worldwide were 14,075.51 (95% uncertainty interval: 6124.33-21,618.11), and the number of deaths was 13,743.44 (95% uncertainty interval: 6019.13-17,938.53), both of which were lower than that in 1990. With the improvement of the sociodemographic index, the incident cases, the number of deaths, age-standardized incidence rate, age-standardized incidence death rate, and disability-adjusted life years of rabies all showed downward trends. Adolescents and adults aged <50 years represented the majority of rabies cases worldwide.

CONCLUSION

The global disease burden of rabies has declined over the past 30 years. Furthermore, the disease burden of rabies was closely related to the sociodemographic index level.

Descriptive cross-sectional study on major bovine diseases and associated risk factors in north-eastern Ecuadorian Amazon

Cattle raising is a crucial element of production systems in the tropics and subtropics. However, in recent years, global public health security has been threatened by disease emergence. In Orellana Province, livestock is the most important activity to generate economic income. Nevertheless, there is no available data about Animal Health status. With this objective, a study was performed to describe the major Bovine diseases recorded between 2011 to 2019, and the main Risk factors associated. Data on main Bovine diseases were retrieved from the World Animal Health Information System database. Whereas Bovine population data used to calculate the prevalence rates and confidence intervals were obtained from Ecuador's Ministry of Agriculture. By contrast, the Risk factors identified with an epidemiological questionnaire were applied to 300 livestock farmers. As a result, from 2011 to 2019 in Orellana has been confirmed: 90 cases of Infectious Bovine Rhinotracheitis (31.58%), Bovine Rabies by hematophagous bats (Desmodus rotundus), 83 cases (29.12%), Bovine viral diarrhea with 43 cases (15.10%), Brucellosis by Brucella abortus 35 cases, which was (12.28%), and 34 cases related to Enzootic bovine leukosis (11.92%). Overall, the prevalence rates ranged from (0.24 to 15.37%). In addition, farm size, presence of forest, herd, and paddock sizes, cutting frequency of forages, and other animal species were involved as Risk factors (OR = 3.15 to 11.75; 95% CI, 0.01 to 0.69). In conclusion, there are animal diseases with reproductive and neurologic symptomology and high-Risk factors implicated in the transmission. Consequently, space-temporal and seroprevalence epidemiological studies should be performed in Orellana.

Rabies virus isolated from insectivorous bats induces different inflammatory responses in experimental model

Rabies virus (RABV) is a neurotropic virus that causes fatal neuroinflammation in mammals. The insectivorous bat RABV strains are less pathogenic for mice than strains associated with other reservoirs. We characterized the tissue inflammatory response in the CNS of RABV isolated from insectivorous bats. Eptesicus furinalis (EPBRV)-infected mice had a robust inflammatory response and a greater amount of IL-1β, IL-6 and TNF-α, while Myotis nigricans (MNBRV)-infected mice showed a higher expression of IL-17 and greater activation of IFN-β. New approaches to understand the inflammatory response to different mechanisms of action may provide insights for the development of novel therapies for rabies.

Accounting for animal movement improves vaccination strategies against wildlife disease in heterogeneous landscapes

Oral baiting is used to deliver vaccines to wildlife to prevent, control, and eliminate infectious diseases. A central challenge is how to spatially distribute baits to maximize encounters by target animal populations, particularly in urban and suburban areas where wildlife such as raccoons (Procyon lotor) are abundant and baits are delivered along roads. Methods from movement ecology that quantify movement and habitat selection could help to optimize baiting strategies by more effectively targeting wildlife populations across space. We developed a spatially explicit, individual-based model of raccoon movement and oral rabies vaccine seroconversion to examine whether and when baiting strategies that match raccoon movement patterns perform better than currently used baiting strategies in an oral rabies vaccination zone in greater Burlington, Vermont, USA. Habitat selection patterns estimated from locally radio-collared raccoons were used to parameterize movement simulations. We then used our simulations to estimate raccoon population rabies seroprevalence under currently used baiting strategies (actual baiting) relative to habitat selection-based baiting strategies (habitat baiting). We conducted simulations on the Burlington landscape and artificial landscapes that varied in heterogeneity relative to Burlington in the proportion and patch size of preferred habitats. We found that the benefits of habitat baiting strongly depended on the magnitude and variability of raccoon habitat selection and the degree of landscape heterogeneity within the baiting area. Habitat baiting improved seroprevalence over actual baiting for raccoons characterized as habitat specialists but not for raccoons that displayed weak habitat selection similar to radiocollared individuals, except when baits were delivered off roads where preferred habitat coverage and complexity was more pronounced. In contrast, in artificial landscapes with either more strongly juxtaposed favored habitats and/or higher proportions of favored habitats, habitat baiting performed better than actual baiting, even when raccoons displayed weak habitat preferences and where baiting was constrained to roads. Our results suggest that habitat selection-based baiting could increase raccoon population seroprevalence in urban-suburban areas, where practical, given the heterogeneity and availability of preferred habitat types in those areas. Our novel simulation approach provides a flexible framework to test alternative baiting strategies in multiclass landscapes to optimize bait-distribution strategies.

Spatio-temporal dynamics of rabies and habitat suitability of the common marmoset Callithrix jacchus in Brazil

Rabies transmitted by wildlife is now the main source of human rabies in the Americas. The common marmoset, Callithrix jacchus, is considered a reservoir of rabies causing sporadic and unpredictable human deaths in Brazil, but the extent of the spillover risk to humans remains unknown. In this study, we described the spatiotemporal dynamics of rabies affecting C. jacchus reported to Brazil’s Ministry of Health passive surveillance system between 2008 and 2020, and combined ecological niche modelling with C. jacchus occurrence data to predict its suitable habitat. Our results show that 67 outbreaks (91 cases) of rabies affecting C. jacchus were reported by 41 municipalities between January 2008 and October 2020, with a mean of 5 outbreaks/year [range: 1–14]. The maximum number of outbreaks and municipalities reporting cases occurred in 2018, coinciding with higher surveillance of primate deaths due to Yellow Fever. A mean of 3 [1–9] new municipalities reported outbreaks yearly, suggesting potential spatial expansions of the C. jacchus variant in northeastern Brazil and emerging rabies spillover from vampire bat Desmodus rotundus to C. jacchus in the north and south. Outbreaks were concentrated in the states of Ceará (72%) and Pernambuco (16%) up to 2012, but are now reported in Piauí since 2013, in Bahia since 2017 (D. rotundus’ antigenic variant, AgV3) and in Rio de Janeiro since 2019 (AgV3). Besides confirming suitable habitat for this primate in the northeast and the east coast of Brazil, our Maximum Entropy model also predicted suitable habitat on the north and the west states of the country but predicted low habitat suitability among inland municipalities of the Caatinga biome reporting rabies. Our findings revealed new areas reporting rabies infecting C. jacchus, highlighting the need to implement strategies limiting spillover to humans and to better understand the drivers of C. jacchus rabies dynamics.

Rabies virus is the deadliest virus affecting mammals. In Brazil, rabies transmitted by the common marmoset primate is emerging and causing unpredictable human deaths. This primate once endemic to the northeast of the country has now invaded regions in the south throughout human-mediated introductions. However, the dynamics of rabies in this primate and the extend of spillover risk to humans remain unknown. We found that outbreaks of rabies in this marmoset reported to the Ministry of Health are continuously reported in new areas, including three new states since 2012 and three states reporting rabies originated from the common vampire bat. We also showed that this primate has suitable habitat to invade other states in the north and west of Brazil. Preventive strategies should be implemented to limit further rabies spillover to humans in new areas.

Filter Papers to Collect Blood Samples from Dogs: An Easier Way to Monitor the Mass Vaccination Campaigns against Rabies?

Rabies is a deadly viral disease present mainly in low-income countries of Africa and Asia. Dogs are the main reservoir and the source of human deaths. Mass vaccination campaigns of dogs are pivotal to achieve rabies elimination. The monitoring of the immune response of the dog population is necessary to evaluate the effectiveness of these campaigns, taking into account field conditions. This study explores the feasibility and the performance of a new tool using filter papers (FPs) to collect blood samples associated with an Enzyme-Linked ImmunoSorbent Assay (ELISA) titration of rabies antibodies in dogs. A total of 216 eluates from FP samples were collected from 111 dogs kept in experimental facilities in France and 29 dogs from the field in Tunisia. Sera were also analyzed using both the Fluorescence Antibody Virus Neutralization test (FAVNt) and ELISA. A high specificity (98.0%) was obtained by testing FP blood eluates from 51 unvaccinated dogs, with the results compared with those of FAVNt and ELISA on serum samples. The coefficients of concordance between FP eluates and tested sera were 88.9% for FAVNt and 88.0% for ELISA. Blood filter papers coupled with the titration of rabies antibodies by ELISA provide a reliable, simple, and effective solution to overcome the issues of the logistics and transport of samples, especially in low-income countries.

Knowledge, attitudes, practices (KAP) and control of rabies among community households and health practitioners at the human-wildlife interface in Limpopo National Park, Massingir District, Mozambique

Background

Rabies is a viral zoonotic disease that kills more than 26,000 people each year in Africa. In Mozambique, poverty and inadequate surveillance result in gross underreporting and ineffective control of the disease in animals and people. Little is known of the role of human attitudes and behaviour in prevention or control of rabies, thus this study was undertaken to assess the knowledge, attitudes and practices amongst selected households and health practitioners in one affected area, the Limpopo National Park (LNP), Massingir district.

Methodology

A cross-sectional study was conducted among 233 households in eight villages in LNP and among 42 health practitioners from eight health facilities in Massingir district between 2016 and 2018. Consenting household representatives aged 18 years or over were purposively selected. A KAP survey was administered to obtain information on dog ownership and knowledge of rabies, host species affected, modes of transmission, symptoms, recommended treatment and preventive methods.

Similar to household study participants, health practitioners were purposively selected and completed the questionnaire during the investigators’ visit. The questionnaire sought information on knowledge of rabies, management of bite wounds, vaccination sites and schedules of pre- and post-exposure prophylaxis. Descriptive and inferential data analyses were performed using SPSS software version 18.0.

Results

Approximately twenty per cent (18.9%; 95% CI: 14.3–24.3) and 13.3% (95% CI: 9.4–18.1) of households had good knowledge and practices of rabies, respectively. For health practitioners, only 16.7% (95% CI: 7.5–31.9) had good knowledge, whilst 33.3% (95% CI: 20.0–49.7) adopted adequate attitudes/practices towards the disease.

Conclusions/Significance

In conclusion, both households and health practitioners displayed poor levels of knowledge and adopted bad attitudes and practices towards rabies. The former, had more gaps in their attitudes and practices towards the disease. Village location and education level (P < .05) and similarly, sex and occupation, were found to be statistically associated with good knowledge of rabies among households as compared to HPs. Overall, a lack of community-based education and professional retraining courses contribute significantly to poor awareness of rabies in the LNP of Mozambique. Enhancing public health knowledge should consequently reduce dog-mediated human rabies deaths in this country.

In Mozambique, rabies is maintained primarily by the domestic dog, the principal vector and host species responsible for the majority of human cases dating back to the early 1900s. Control of animal rabies has historically been undertaken by government veterinary authorities, with limited involvement of the health and environment sectors. In the Massingir District in general, and in Limpopo National Park (LNP) in particular, parenteral dog rabies mass-vaccination campaigns and the provision of post-exposure prophylaxis are inconsistent. Limited resources for dog vaccination campaigns, insufficient veterinary field staff, inefficient disease notification procedures and inadequate training of health practitioners constraint effective rabies control across the country. Awareness of good practices regarding management of bite wounds among local community members and health practitioners is crucial to reducing rabies deaths. The results obtained in this study will inform government policy on practical interventions in the control of dog and human rabies.

A database of common vampire bat reports

The common vampire bat (Desmodus rotundus) is a sanguivorous (i.e., blood-eating) bat species distributed in the Americas from northern Mexico southwards to central Chile and Argentina. Desmodus rotundus is one of only three mammal species known to feed exclusively on blood, mainly from domestic mammals, although large wildlife and occasionally humans can also serve as a food source. Blood feeding makes D. rotundus an effective transmissor of pathogens to its prey. Consequently, this species is a common target of culling efforts by various individuals and organizations. Nevertheless, little is known about the historical distribution of D. rotundus. Detailed occurrence data are critical for the accurate assessment of past and current distributions of D. rotundus as part of ecological, biogeographical, and epidemiological research. This article presents a dataset of D. rotundus historical occurrence reports, including >39,000 locality reports across the Americas to facilitate the development of spatiotemporal studies of the species. Data are available at 10.6084/m9.figshare.15025296.

Measurement(s)	occurrence report
Technology Type(s)	digital curation
Sample Characteristic - Organism	Desmodus rotundus
Sample Characteristic - Location	North America • South America

Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.18745316

Household survey on owned dog population and rabies knowledge in selected municipalities in Bulacan, Philippines: A cross-sectional study

Background

Despite the effort to eradicate rabies in the Philippines, human rabies cases have not decreased in the past decade. Rabid dogs pose the most significant hazard in the countries with the highest burden of rabies, and 70% rabies vaccine coverage is recommended for dogs in high-risk areas. Ascertaining the owned dog population and community knowledge on rabies can help improve vaccine coverage and information campaigns.

Methodology/Principal findings

We conducted a cross-sectional survey in six randomly selected communities (five urban, one rural) in Central Luzon, Philippines. We first conducted the complete mapping of 9,173 households and then randomly selected 727 households. More than half (54.1%) of the households owned dogs (1.21 dogs/household). In the 727 households, we identified 878 owned dogs and 3256 humans. According to these results, the dog-to-human ratio was approximately 1:3.7. Only 8.8% of households reported a history of dog bite in 2019. Among dog-owning households, 31% reported that they allow their dogs to roam freely. Of the recorded dogs, 35.9% have never been vaccinated, and only 3.5% were spayed or castrated. Factors associated with lower rabies knowledge include (1) no education aOR: 0.30 (0.16–0.59), and (2) only primary school education aOR: 0.33 (0.22–0.49). In contrast, factors associated with higher knowledge include (1) owning a dog and not allowing them to roam freely aOR: 2.01 (1.41–2.87) and (2) owning a dog and allowing them to roam freely aOR: 1.84 (1.17–2.92), when compared to those with no dogs.

Conclusions/Significance

We identified a larger dog population in the community than the usual estimates (1:10), suggesting that annual vaccine needs in the Philippines must be reassessed. Our survey shows a relatively good understanding of rabies; however, awareness of the concept of rabies as a disease, and how animals and humans can acquire it, is lacking.

Rabies outbreak in black-backed jackals (Canis mesomelas), South Africa, 2016

Rabies, a fatal and vaccine-preventable disease, is endemic throughout Africa. In 2016, a rabies outbreak occurred in black-backed jackals (Canis mesomelas) along the western boundary of Gauteng Province, South Africa. We investigated the possible drivers of the 2016 outbreak and established its origin. Using spatio-temporal locations of cases, we applied logistic regression and Geographic Information System techniques to investigate environmental covariates driving occurrences of emerging rabies cases in Gauteng Province. About 53.8% of laboratory-confirmed lyssaviruses in Gauteng Province in 2016 originated from jackals. Phylogenetic trees reconstructed from a partial region of the glycoprotein gene of these and historical rabies viruses (RABVs) demonstrated the lyssaviruses to be of canid origin with 97.7% nucleotide sequence similarity. The major cluster comprised jackal RABVs from the 2012 KwaZulu/Natal outbreak and the 2016 outbreak in Gauteng Province. The second cluster was composed of both jackal and dog RABVs. Both clusters correlated with independent RABV introductions into Gauteng by dogs and jackals, respectively. This study demonstrated an expansion of a jackal rabies cycle from north-west Province into Gauteng Province during the 2016 dry period, as jackals ranged widely in search for food resources leading to increased jackal-dog interactions, reminiscent of the intricate links of domestic and wildlife rabies cycles in South Africa.

High-throughput sequencing technologies in the detection of livestock pathogens, diagnosis, and zoonotic surveillance

Increasing globalization, agricultural intensification, urbanization, and climatic changes have resulted in a significant recent increase in emerging infectious zoonotic diseases. Zoonotic diseases are becoming more common, so innovative, effective, and integrative research is required to better understand their transmission, ecological implications, and dynamics at wildlife-human interfaces. High-throughput sequencing (HTS) methodologies have enormous potential for unraveling these contingencies and improving our understanding, but they are only now beginning to be realized in livestock research. This study investigates the current state of use of sequencing technologies in the detection of livestock pathogens such as bovine, dogs (Canis lupus familiaris), sheep (Ovis aries), pigs (Sus scrofa), horses (Equus caballus), chicken (Gallus gallus domesticus), and ducks (Anatidae) as well as how it can improve the monitoring and detection of zoonotic infections. We also described several high-throughput sequencing approaches for improved detection of known, unknown, and emerging infectious agents, resulting in better infectious disease diagnosis, as well as surveillance of zoonotic infectious diseases. In the coming years, the continued advancement of sequencing technologies will improve livestock research and hasten the development of various new genomic and technological studies on farm animals.

Preparation of Anti-Rabies Virus N Protein IgYs by DNA Immunization of Hens Using Different Types of Adjuvants

DNA immunization has been used to study vaccination methods and for production of specific antibodies. The present study aimed to apply DNA immunization to prepare specific IgYs, which react against rabies virus N protein (RV-N) and can be used to research and diagnose rabies virus. The DNA sequence of RV-N was ligated into a pcDNA 3.1 plasmid for constructing pcDNA-N. Eight hens were divided into four groups. Group 1 comprised the control group (non-immunized). In Groups 2, 3, and 4, hens were injected intramuscularly with pcDNA-N (400 µg/hen). Eight injections were administered every other week. From the 4th week, an adjuvant was injected in addition to pcDNA-N. Freund's complete adjuvant (FCA) and λ-carrageenan were administered to Groups 3 and 4, respectively. Eggs were collected daily, and the specific antibody activities of egg yolks were measured by ELISA. IgYs were purified from pooled egg yolks at 16–19 weeks post-administration in each group. The detection sensitivities of the RV-N were compared using purified IgY as the primary antibody for ELISA, dot blotting, and western blotting. Egg yolks from one of the two hens in Group 2 (pcDNA-N alone) and all hens in Groups 3 (pcDNA-N + FCA) and 4 (pcDNA-N + λCarra) had increased ELISA values. The combined use of λ-carrageen in DNA immunization resulted in an adjuvant effect comparable to that of FCA. Each purified specific IgY detected RV-N in the ELISA, western blotting, and dot blotting; however, the detection sensitivity differed. Higher detection sensitivity of the +λCarra IgY was observed by ELISA, whereas there was higher detection sensitivity of +FCA IgY in western blotting and dot blotting. In summary, anti-rabies virus N protein IgY was prepared through DNA immunization of hens using FCA or λ-carrageenan as adjuvants and can be used as a primary antibody to detect rabies viruses.