Phylogenetic analysis of rabies viruses from Burkina Faso, 2007

Emerging Genomic Trends on Rabies Virus in Davao Region, Philippines, 2018-2021

Rabies, caused by the rabies virus (RABV), remains a significant public health issue in the Philippines despite efforts to control it. To eliminate rabies by 2030, effective surveillance strategies are crucial. In this study, we examined RABV evolution and phylodynamics in the Davao Region using genome sequences from Davao City and nearby provinces. We adapted the RABV ARTIC Protocol for Oxford Nanopore High-Throughput Sequencing to optimize workflow efficiency under limited resources. Comparing new virus samples collected from June 2019 to June 2021 (n = 38) with baseline samples from June 2018 to May 2019 (n = 49), new sub-clades were observed in the phylogenetic tree, suggesting divergence from older variants that were previously undetected. Most of the new viruses belonged to the Asian SEA4_A1.1.1 lineage, but new (SEA4_B1 and SEA4_B1.1) and emerging (SEA4_B1.1_E1) lineages that have never been reported in the Philippines were also identified. The baseline study reported phylogeographic clustering of RABV isolates from the same areas. However, this pattern was disrupted in the current biosurveillance, with variants detected in areas outside the original cluster. Furthermore, our findings revealed significant transmission routes between Davao City and neighboring provinces, contrasting with the predominantly intra-city transmission observed in the baseline study. These results underscore the need for ongoing and timely genomic surveillance to monitor genetic diversity changes and the emergence of novel strains, as well as to track alterations in transmission pathways. Implementing cost-effective next-generation sequencing workflows will facilitate the integration of genomic surveillance into rabies control programs, particularly in resource-limited settings. Collaborations between different sectors can empower local laboratories and experts in genomic technologies and analysis.

Dog rabies control in West and Central Africa: A review

Rabies is a neglected but preventable zoonotic disease that predominantly affects the most vulnerable populations living in remote rural areas of resource-limited countries. To date, every country on the African mainland is considered endemic for dog-mediated rabies with an estimated 21'500 human rabies deaths occurring each year. In 2018, the United Against Rabies collaboration launched the Global Strategic Plan to end human deaths from dog-mediated rabies by 2030. The epidemiology of rabies from most Western and Central African countries remains poorly defined, making it difficult to assess the overall rabies situation and progress towards the 2030 goal. In this review, we attempt to provide an overview of the current rabies situation in 22 West and Central African countries based on published scientific literature and information obtained from rabies focal points. To this end, information was collected on i) established surveillance, ii) diagnostic capacity, iii) post-exposure prophylaxis (PEP) availability and coverage, iv) dog population estimates, v) dog vaccination campaigns, vi) animal and human health communication (One Health), vii) molecular studies, viii) Knowledge, Attitude and Practices (KAP), ix) cost estimates and x) national control strategies. Although rabies is a notifiable disease in the majority of the studied countries, national surveillance systems do not adequately capture the disease. A general lack of rabies diagnostic capacity has an additional negative impact on rabies surveillance and attempts to estimate rabies burden. Recurrent shortages of human rabies vaccine are reported by all of the countries, with vaccine availability usually limited to major urban centers but no country has yet adopted the new WHO-recommended 1-week intradermal vaccination regimen. Most countries carry out subsidized mass dog vaccination campaigns on World Rabies Day. Such activities are indispensable to keep rabies in the public consciousness but are not of the scale and intensity that is required to eliminate rabies from the dog population. Countries will need to scale up the intensity of their campaigns, if they are to progress towards the 2030 goal. But more than half of the countries do not yet have reliable figures on their dog populations. Only two countries reached stage 2 on the Stepwise Approach towards Rabies Elimination ladder - indicating that their national governments have truly prioritized rabies elimination and are thus providing the necessary support and political buy-in required to achieve success. In summary, the sub-region of West and Central Africa seems to be divided into countries which have accepted the challenge to eliminate rabies with governments committed to pushing forward rabies elimination, while other countries have achieved some progress, but elimination efforts remain stuck due to lacking government commitment and financial constraints. The possibility to meet the 2030 goal without international solidarity is low, because more than two-thirds of the countries rank in the low human development group (HDI ≤ 152). Leading countries should act as role models, sharing their experiences and capacities so that no country is left behind. Unified and with international support it is possible to reach the common goal of zero human rabies deaths by 2030.

Dog ownership, demographics, owners' knowledge of rabies, and factors associated with canine rabies vaccination in urban and rural areas of Dedougou, Burkina Faso

Rabies is a prioritized zoonotic disease in Burkina Faso and is known as a major zoonotic disease with high public health importance. This investigation was conducted to assess community knowledge, dog ecology and demographics, and factors associated with dog vaccination against rabies in the urban and rural areas of Dedougou. Three hundred and sixteen (316) dog-owning households were surveyed in the rural and urban areas of Dedougou using a semi-structured questionnaire. Among participants, 55.7% lived in rural area, and 59.8% were farmers. Only 34.5% of participants had satisfactory knowledge of rabies. About 22% were aware of the required age of dogs’ primo vaccination against rabies while 55.7% knew the frequency of booster vaccination. Participants living in households with less than five persons were significantly more likely to be aware of rabies than those living in households with the higher number of persons (P<0.05). Participants who were aware of rabies were more likely to vaccinate their dogs compared to those who were not aware of rabies (P<0.05). In total, 2930 persons were recorded in visited households with 60.6% from rural area, and an average household size of 9.27 persons. Three hundred and thirty seven dogs were found in surveyed households’ and 54.9% were from rural area. In overall, a dog per human ratio of 1:8.7 was determinated. Regarding dog ownership practices, the majority of respondents reported that they provided their dogs with water (84.5%) and food (84.8%). This research reported supplementary data on dog ecology and rabies, which could be useful for rabies control planning in Burkina Faso.

Incidence and seroprevalence of rabies virus in humans, dogs and other animal species in Africa, a systematic review and meta-analysis

Rabies is transmitted to humans mainly by dogs but also by other animal species. Reliable data on the incidence of Rabies virus (RABV) in humans, dogs, and other animal species in Africa, could be essential in the implementation of a global strategic plan to eliminate the RABV by 2030 as adopted by the WHO, OIE, and FAO. We searched the Pubmed, Embase, Scopus, African Journal Online, and African Index Medicus databases for relevant studies that report data on the incidence of RABV in Africa up to February 17, 2020. Information on active and past RABV exposures in various categories of dogs, humans and other animal species were extracted. Incidence and seroprevalence estimates were pooled using a random-effect meta-analysis. We included 73 articles which provided 142 RABV incidence and seroprevalence records in 21 African countries. The estimated incidence of RABV in 222 humans, 15,600 dogs, and 12,865 other animal species was 83.4% (95% CI = 64.6–96.5), 44.1% (95% CI = 35.1–53.4), and 41.4% (95% CI = 29.6–53.8), respectively. The estimated seroprevalence of RABV in 420 humans, 3577 dogs, and 8,55 other animal species was 33.8% (95% CI = 21.9–46.8), 19.8% (95% CI = 13.3–27.3), and 3.6% (95% CI = 0.3–9.2), respectively. The incidence of RABV in general was higher in suspected rabid dogs, other animal species of the Orders Perissodactyla, Artiodactyla and Carnivora. The incidence of RABV was higher for humans in regions of West and East Africa, for dogs in urban areas and in regions of Central and South Africa, and for animals of the order Perissodactyla in urban areas. This meta-analysis demonstrated a high incidence of RABV in Africa. Itis necessary to improve surveillance system to provide reliable data on RABV in Africa, essential for the implementation of an effective control strategy.

Rabies control in Liberia: Joint efforts towards zero by 30

Despite declaration as a national priority disease, dog rabies remains endemic in Liberia, with surveillance systems and disease control activities still developing. The objective of these initial efforts was to establish animal rabies diagnostics, foster collaboration between all rabies control stakeholders, and develop a short-term action plan with estimated costs for rabies control and elimination in Liberia. Four rabies diagnostic tests, the direct fluorescent antibody (DFA) test, the direct immunohistochemical test (dRIT), the reverse transcriptase polymerase chain reaction (RT-PCR) assay and the rapid immunochromatographic diagnostic test (RIDT), were implemented at the Central Veterinary Laboratory (CVL) in Monrovia between July 2017 and February 2018. Seven samples (n=7) out of eight suspected animals were confirmed positive for rabies lyssavirus, and molecular analyses revealed that all isolates belonged to the Africa 2 lineage, subgroup H. During a comprehensive in-country One Health rabies stakeholder meeting in 2018, a practical workplan, a short-term action plan and an accurately costed mass dog vaccination strategy were developed. Liberia is currently at stage 1.5/5 of the Stepwise Approach towards Rabies Elimination (SARE) tool, which corresponds with countries that are scaling up local-level interventions (e.g. dog vaccination campaigns) to the national level. Overall an estimated 5.3 - 8 million USD invested over 13 years is needed to eliminate rabies in Liberia by 2030. Liberia still has a long road to become free from dog-rabies. However, the dialogue between all relevant stakeholders took place, and disease surveillance considerably improved through implementing rabies diagnosis at the CVL. The joint efforts of diverse national and international stakeholders laid important foundations to achieve the goal of zero dog-mediated human rabies deaths by 2030.

Molecular characterization of rabies viruses from two western provinces of the Democratic Republic of the Congo (2008-2017)

Although rabies is enzootic in the Democratic Republic of the Congo, there is very little molecular epidemiological information about the viruses circulating in animals. In this study, a fragment of the rabies virus (RABV) nucleoprotein gene was amplified and sequenced from 21 animal brain samples collected in two western provinces of the country between 2008 and 2017. The samples tested were from cat (n = 1), dog (n = 17), goat (n = 2), and sheep (n = 1). Phylogenetic analysis revealed that the sequences generated were highly similar to each other and belonged to lineage Africa 1b clustering with a single sample identified in a canine in the Republic of Congo in 2014. This is the first molecular epidemiological study of RABV in the DRC and the data generated will assist authorities in the development of effective control strategies for rabies in the country.

Molecular Detection of Rabies Lyssaviruses from Dogs in Southeastern Nigeria: Evidence of TransboundaryTransmission of Rabies in West Africa

Despite being the first country to register confirmed cases of Mokola and Lagos bat lyssaviruses (two very distant lyssaviruses), knowledge gaps, particularly on the molecular epidemiology of lyssaviruses, still exist in Nigeria. A total of 278 specimens were collected from dogs in southeastern Nigeria between October 2015 and July 2016, and 23 (8.3%) of these tested positive for lyssaviruses with the direct fluorescent antibody test (DFA). The lyssaviruses were genetically characterized by amplifying the highly conserved nucleoprotein (N) gene of the rabies lyssaviruses (RABVs) of the viral genome. Phylogenetic analyses of the nucleotide sequences showed that all the RABV sequences in this study were of the Africa-2 lineage. Our results demonstrated that transboundary transmission of rabies lyssavirus is a key event, given that one of the RABV sequences (MN196576) clustered with rabies variants from neighboring Niger Republic. Furthermore, three RABVs from dogs from Anambra State clustered separately forming a novel and distinct group. Our results demonstrated that transboundary transmission of RABLVs is a key driver in the spread of rabies in West Africa. In order for the successful control of this zoonotic disease, a multinational stepwise surveillance and elimination of rabies in Africa by 2030 is probably the solution for regional elimination.

Viral infections of the central nervous system in Africa

Viral infections are a major cause of human central nervous system infection, and may be associated with significant mortality, and long-term sequelae. In Africa, the lack of effective therapies, limited diagnostic and human resource facilities are especially in dire need. Most viruses that affect the central nervous system are opportunistic or accidental pathogens. Some of these viruses were initially considered harmless, however they have now evolved to penetrate the nervous system efficiently and exploit neuronal cell biology thus resulting in severe illness. A number of potentially lethal neurotropic viruses have been discovered in Africa and over the course of time shown their ability to spread wider afield involving other continents leaving a devastating impact in their trail. In this review we discuss key viruses involved in central nervous system disease and of major public health concern with respect to Africa. These arise from the families of Flaviviridae, Filoviridae, Retroviridae, Bunyaviridae, Rhabdoviridae and Herpesviridae. In terms of the number of cases affected by these viruses, HIV (Retroviridae) tops the list for morbidity, mortality and long term disability, while the Rift Valley Fever virus (Bunyaviridae) is at the bottom of the list. The most deadly are the Ebola and Marburg viruses (Filoviridae). This review describes their epidemiology and key neurological manifestations as regards the central nervous system such as meningoencephalitis and Guillain-Barré syndrome. The potential pathogenic mechanisms adopted by these viruses are debated and research perspectives suggested.

Rabies - epidemiology, pathogenesis, public health concerns and advances in diagnosis and control: a comprehensive review

Rabies is a zoonotic, fatal and progressive neurological infection caused by rabies virus of the genus Lyssavirus and family Rhabdoviridae. It affects all warm-blooded animals and the disease is prevalent throughout the world and endemic in many countries except in Islands like Australia and Antarctica. Over 60,000 peoples die every year due to rabies, while approximately 15 million people receive rabies post-exposure prophylaxis (PEP) annually. Bite of rabid animals and saliva of infected host are mainly responsible for transmission and wildlife like raccoons, skunks, bats and foxes are main reservoirs for rabies. The incubation period is highly variable from 2 weeks to 6 years (avg. 2-3 months). Though severe neurologic signs and fatal outcome, neuropathological lesions are relatively mild. Rabies virus exploits various mechanisms to evade the host immune responses. Being a major zoonosis, precise and rapid diagnosis is important for early treatment and effective prevention and control measures. Traditional rapid Seller's staining and histopathological methods are still in use for diagnosis of rabies. Direct immunofluoroscent test (dFAT) is gold standard test and most commonly recommended for diagnosis of rabies in fresh brain tissues of dogs by both OIE and WHO. Mouse inoculation test (MIT) and polymerase chain reaction (PCR) are superior and used for routine diagnosis. Vaccination with live attenuated or inactivated viruses, DNA and recombinant vaccines can be done in endemic areas. This review describes in detail about epidemiology, transmission, pathogenesis, advances in diagnosis, vaccination and therapeutic approaches along with appropriate prevention and control strategies.

Molecular characterization and phylogenetic relatedness of dog-derived Rabies Viruses circulating in Cameroon between 2010 and 2016

Rabies is enzootic among dog populations in some parts of Cameroon and the risk of human rabies is thought to be steadily high in these regions. However, the molecular epidemiology of circulating Rabies Virus (RABV) has been hardly considered in Cameroon as well as in most neighboring central African countries. To address this fundamental gap, 76 nucleoprotein (N) gene sequences of dog-derived RABV were obtained from 100 brain specimens sampled in Cameroon from 2010 to 2016. Studied sequences were subjected to molecular and phylogenetic analyses with reference strains retrieved from databases. The 71 studied Africa-1 isolates displayed 93.5–100% nucleotide (nt) and 98.3–100% amino-acid (aa) identities to each other while, the 5 studied Africa-2 isolates shared 99.4–99.7% sequence similarities at nt and aa levels. Maximum Likelihood based phylogenies inferred from nucleotide sequences confirmed all studied RABV isolates as members of the dog-related species 1 of the Lyssavirus genus. Individual isolates could be unambiguously assigned as either the Africa-1 subclade of the Cosmopolitan clade or the Africa 2 clade. The Africa-1 subclade appeared to be more prevalent and diversified. Indeed, 70 studied isolates segregated into 3 distinct circulating variants within Africa-1a lineage while a unique isolate was strikingly related to the Africa-1b lineage known to be prevalent in the neighboring Central African Republic and eastern Africa. Interestingly, all five Africa-2 isolates fell into the group-E lineage even though they appeared to be loosely related to databases available reference RABV; including those previously documented in Cameroon. This study uncovered the co-circulation of several Africa-1 and Africa-2 lineages in the southern regions of Cameroon. Striking phylogenetic outcasts to the geographic differentiation of RABV variants indicated that importation from close regions or neighboring countries apparently contributes to the sustainment of the enzootic cycle of domestic rabies in Cameroon.

Rabies has been repeatedly reported among dog populations in Cameroon, especially in Yaounde, its capital city. However, the relative rates and genetic variability of Rabies Virus (RABV) variants circulating among dog populations in Cameroon are still to be documented. This study aimed to estimate the frequency and genetic diversity of RABV isolates originating from rabid dogs in the southern regions of Cameroon from 2010 to 2016. Overall, 76 of the 100 dog-derived RABV isolates sampled in Cameroon from 2010 to 2016 were successfully characterized. Our findings revealed that studied isolates belonged to the dog-related species 1 of the Lyssavirus genus, specifically 70 Africa-1a, 1 Africa-1b and 5 Africa-2 group-E lineages. The general phylogenetic pattern suggested an in-country geographic differentiation of the circulating RABV variants. This apparent geographic differentiation was contradicted by striking outcasts indicating importation from close or distant regions. Overall, this study uncovered the co-circulation of several Africa-1 and Africa-2 lineages in some southern regions of Cameroon, thus providing base-line molecular data that would be of interest for future stages of implementation of the rabies surveillance and control plan that is being setup in Cameroon.

Molecular Characterization of Canine Rabies Virus, Mali, 2006-2013

We genetically characterized 32 canine rabies viruses isolated in Mali during 2006–2013 and identified 3 subgroups that belonged to the Africa 2 lineage. We also detected subgroup F rabies virus. This information should be useful for development of mass vaccination campaigns for dogs and eventual large-scale control programs in this country.

Evolutionary history of rabies in Ghana

Rabies virus (RABV) is enzootic throughout Africa, with the domestic dog (Canis familiaris) being the principal vector. Dog rabies is estimated to cause 24,000 human deaths per year in Africa, however, this estimate is still considered to be conservative. Two sub-Saharan African RABV lineages have been detected in West Africa. Lineage 2 is present throughout West Africa, whereas Africa 1a dominates in northern and eastern Africa, but has been detected in Nigeria and Gabon, and Africa 1b was previously absent from West Africa. We confirmed the presence of RABV in a cohort of 76 brain samples obtained from rabid animals in Ghana collected over an eighteen-month period (2007-2009). Phylogenetic analysis of the sequences obtained confirmed all viruses to be RABV, belonging to lineages previously detected in sub-Saharan Africa. However, unlike earlier reported studies that suggested a single lineage (Africa 2) circulates in West Africa, we identified viruses belonging to the Africa 2 lineage and both Africa 1 (a and b) sub-lineages. Phylogeographic Bayesian Markov chain Monte Carlo analysis of a 405 bp fragment of the RABV nucleoprotein gene from the 76 new sequences derived from Ghanaian animals suggest that within the Africa 2 lineage three clades co-circulate with their origins in other West African countries. Africa 1a is probably a western extension of a clade circulating in central Africa and the Africa 1b virus a probable recent introduction from eastern Africa. We also developed and tested a novel reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay for the detection of RABV in African laboratories. This RT-LAMP was shown to detect both Africa 1 and 2 viruses, including its adaptation to a lateral flow device format for product visualization. These data suggest that RABV epidemiology is more complex than previously thought in West Africa and that there have been repeated introductions of RABV into Ghana. This analysis highlights the potential problems of individual developing nations implementing rabies control programmes in the absence of a regional programme.