Evaluation of an Immunochromatographic Assay as a Canine Rabies Surveillance Tool in Goa, India

Prospects for dog rabies elimination in Nigeria by 2030

The attainment of the global target of zero dog-mediated human rabies by 2030 depends on functional rabies programmes. Nigeria, a rabies-endemic country, and the most populous country in Africa has a very poor rabies control strategy with a score of 1.5 out of 5 based on the Stepwise Approach towards Rabies Elimination (SARE). In this article, we report a scoping review that we conducted to highlight the strengths, weaknesses, opportunities and threats as well as situational analysis of rabies control in Nigeria and suggest a timeline for key activities that are needed to ensure zero by 30. Our findings reveal that rabies is grossly under-reported as only 998 human and 273 dog-suspected rabies cases were reported across Nigeria between 2017 and 2022. Our literature review also demonstrates a paucity of information on rabies in both human and animal health sectors. A total of 49 studies on dog rabies in Nigeria, with a predominance of reports from the North Central geopolitical region (48%, n = 23) were therefore included in this study. Currently, only 16.2% (n = 6/37) of Nigerian states have available data related to the estimated dog populations, the dog ownership rates, the vaccination status of dogs or the incidence of dog bites. Based on a dog-to-human ratio of 1:16.3, we estimated that the dog population in Nigeria was 12,969,368 (95% CI: 12,320,900-13,617,836). Thus, to attain herd immunity and dog rabies control in Nigeria, at least 9.1 million dogs must be vaccinated annually. Our review reveals that, despite the strengths and available opportunities to achieve rabies control in Nigeria by 2030, the weaknesses and challenges will make the attainment of zero by 30 very difficult or impossible. Nigeria's best-case scenario by the year 2030 is SARE stage 3-4 (control-elimination) out of 5. Otherwise, the rabies control programme might not surpass SARE stages 2-3. To attain zero by 30, Nigeria must re-strategize its current rabies control programme by funding and implementing the national strategic plan for rabies control, creating a rabies desk office in the 37 states (FCT inclusive), rigorously conducting mass vaccination campaigns, providing post-exposure prophylaxis, prioritizing mass enlightenment with a focus on responsible pet ownership and conduct baseline national rabies surveillance in the animal and human health sectors.

Recent updates on laboratory diagnosis of rabies

Rabies is a lethal viral disease transmitted through the bite of rabid animals. India has a high burden of rabies, contributing to a significant proportion of the global deaths. However, under-reporting of the disease is prevalent due to lack of laboratory confirmation. Laboratory diagnosis of rabies plays a crucial role in differentiating the disease from clinical mimics, initiation of appropriate care, implementing infection control measures and informing disease surveillance. This review provides an overview of the recent advancements in laboratory diagnosis of rabies, aimed at updating physicians involved in diagnosis and management of rabies cases in India.

Evaluation of lateral flow devices for postmortem rabies diagnosis in animals in the Philippines: a multicenter study

Expansion of the use of lateral flow devices (LFD) for animal rabies diagnosis can help mitigate the widespread underreporting of rabies. However, this has been hindered by the limited number and small sample size of previous studies. To overcome this limitation, we conducted a multicenter study with a larger sample size to assess the diagnostic accuracy of the ADTEC LFD for postmortem rabies diagnosis in animals. Thirteen governmental animal diagnostic laboratories in the Philippines were involved in this study, and 791 animals suspected of having rabies were tested using both the direct fluorescence antibody test (DFAT) and ADTEC LFD between August 2021 and October 2022. The LFD demonstrated a sensitivity of 96.3% [95% confidence interval (CI): 94.1%-97.9%] and a specificity of 99.7% (95% CI: 98.4%-100%). Notably, false-negative results were more likely to occur in laboratories with lower annual processing volumes of rabies samples in the previous years (adjusted odds ratio 4.97, 95% CI: 1.49-16.53). In this multicenter study, the high sensitivity and specificity of the LFD for the diagnosis of animal rabies, compared to that of the DFAT, was demonstrated, yet concerns regarding false-negative results remain. In areas with limited experience in processing rabies samples, it is essential to provide comprehensive training and careful attention during implementation.

Evaluation of a rapid, chip-based, micro-PCR assay for detection of rabies virus in human and canine specimens

Rabies, a lethal zoonotic encephalitis, remains a significant global health concern, causing an estimated 60 000 annual fatalities worldwide. Dogs serve as the primary reservoirs and vectors for transmitting this infection to humans. Definitive diagnosis of rabies in both human and animal cases necessitates laboratory testing involving various clinical specimens. However, the complexity of laboratory infrastructure and the need for skilled personnel, along with the challenge of maintaining cold-chain integrity during sample referral, hinder the decentralization of diagnostic facilities. This study aimed to assess the efficacy of the Truenat rabies assay, a rapid, portable, semiautomated, and closed PCR-based system, for the diagnosis of rabies in both humans and animals. The Truenat assay demonstrated a sensitivity of 100% and a specificity of 86.96% when compared with the fluorescent antibody test (FAT), as the reference standard, on 147 canine brain samples tested. Notably, the Truenat assay exhibited a sensitivity and specificity of 100% when tested on 48 human brain specimens. Furthermore, an examination of 148 human antemortem samples (cerebrospinal fluid, saliva, and skin biopsy) using both the Truenat assay and a validated real-time reverse transcriptase PCR assay revealed a κ value of 0.505, indicative of a moderate level of agreement between the two tests. Thus, the Truenat assay offers a robust, reliable, and affordable point-of-care solution to enhance rabies diagnostic capacity in endemic areas.

United Against Rabies Forum: The first 2 years

Rabies continues to kill an estimated 59,000 people annually, with up to 99% of human cases transmitted by domestic dogs. The elimination of human deaths from dog-mediated rabies is achievable by applying a One Health approach, and the framework to do this is outlined in Zero by 30: the Global Strategic Plan to end human deaths from dog-mediated rabies by 2030. To build on this global goal, and implement the approaches set out in Zero by 30, the United Against Rabies Forum was launched in 2020. This paper gives a review of the objectives, governance, activities and achievements of the United Against Rabies Forum to date. It also outlines ongoing work, and next steps as the United Against Rabies Forum reviews its first 2 years of activities and identifies priority areas for the coming 12 months.

Evaluation of a real-time mobile PCR device (PCR 1100) for the detection of the rabies gene in field samples

BACKGROUND

The Philippines is ranked among the top countries with 200-300 annual deaths due to rabies. Most human rabies cases have been reported in remote areas, where dog surveillance is inadequate. Therefore, a strategy to effectively improve surveillance in remote areas will increase the number of detections. Detecting pathogens using portable real-time reverse transcription-polymerase chain reaction (RT-PCR) has the potential to be accepted in these areas. Thus, we aimed to develop an assay to detect the rabies virus (RABV) genome by combining the robust primer system LN34 with the PicoGene PCR1100 portable rapid instrument targeting RABV RNA (PCR1100 assay).

METHODS

Procedures were optimised using an LN34 primer/probe set, KAPA3G Plant PCR Kit (KAPA Biosystems), FastGene Scriptase II (NIPPON Genetics), and an artificial positive control RNA.

RESULTS

Positive control RNA showed an analytical limit of detection of 10 copies/µL without false positivity, generating results in approximately 32 min. Compared to dFAT or RT-qPCR using field samples, the sensitivity and specificity of the PCR1100 assay were 100%, and even lower copy numbers (approximately 10 copies/µL) were detected.

CONCLUSIONS

This study demonstrated that the developed assay can detect rabies RNA in field samples. Because dog-mediated rabies is endemic in remote areas, the rapidity, mobility, and practicality of the PCR1100 assay as well as the high sensitivity of the LN34 system make it an ideal tool for the confirmation of rabies in these areas.

From Field Tests to Molecular Tools-Evaluating Diagnostic Tests to Improve Rabies Surveillance in Namibia

Rabies is endemic in Namibia and is present both in wildlife carnivores and domestic free-roaming dogs. The disease thus represents a challenge for public human and veterinary disease control. Namibia has implemented a national strategic plan to control rabies and the country's activities are supported by international organizations. To this end, rabies diagnosis at the Central Veterinary Laboratory (CVL) was improved in the frame of a World Organization for Animal Health (WOAH) laboratory twinning program: from practical sampling techniques and the use of lateral flow devices to a novel universal and discriminatory quantitative real-time Reverse transcription polymerase chain reaction (RT-qPCR), which easily identify dog-associated rabies viruses. The procedures applied and the results can be used as a template to improve rabies laboratory diagnosis.

Elimination of human rabies in Goa, India through an integrated One Health approach

Dog-mediated rabies kills tens of thousands of people each year in India, representing one third of the estimated global rabies burden. Whilst the World Health Organization (WHO), World Organization for Animal Health (OIE) and the Food and Agriculture Organization of the United Nations (FAO) have set a target for global dog-mediated human rabies elimination by 2030, examples of large-scale dog vaccination programs demonstrating elimination remain limited in Africa and Asia. We describe the development of a data-driven rabies elimination program from 2013 to 2019 in Goa State, India, culminating in human rabies elimination and a 92% reduction in monthly canine rabies cases. Smartphone technology enabled systematic spatial direction of remote teams to vaccinate over 95,000 dogs at 70% vaccination coverage, and rabies education teams to reach 150,000 children annually. An estimated 2249 disability-adjusted life years (DALYs) were averted over the program period at 526 USD per DALY, making the intervention 'very cost-effective' by WHO definitions. This One Health program demonstrates that human rabies elimination is achievable at the state level in India.

Capacity Building Efforts for Rabies Diagnosis in Resource-Limited Countries in Sub-Saharan Africa: A Case Report of the Central Veterinary Laboratory in Benin (Parakou)

Rabies has been listed as a priority zoonotic disease in many African countries and the countdown to reach the goal of eliminating dog-mediated human rabies deaths by 2030 means that disease control measures need to be applied fast. In this context, an essential pillar of any national plan to control rabies is the implementation of reliable diagnostic techniques to ensure the success of field surveillance systems. Although many African countries have received international support for the control of rabies–some countries, like Benin, have not received a similar level of support. Indeed, until 2018, Benin was not able to diagnose rabies and rabies diagnosis in animals as well as humans relied solely on observed clinical symptoms. Although the Central Veterinary Laboratory (CVL) of Parakou had the equipment to implement two recommended tests, the lack of specific reagents and skills prevented the implementation of a rabies diagnostic service. Here we present the joint efforts of the national authorities in Benin, intergovernmental agencies, and non-governmental organizations to assess the strengths and weaknesses of the government's rabies control efforts. We have applied the Stepwise Approach toward Rabies Elimination (SARE) analysis, implemented rabies diagnostic capacities at the CVL of Parakou, characterized strains of rabies virus circulating in Benin, and finally integrated an inter-laboratory comparison program.

Lateral flow devices for samples collected by straw sampling method for postmortem canine rabies diagnosis

The direct fluorescent antibody test (dFAT) using brain sample after opening the skull is the standard rabies diagnostic test in animal rabies. However, it is not feasible in many resource-limited settings. Lateral flow devices (LFD) combined with a simple sampling methodology is quicker, simpler, and less hazardous than the standard test and can be a useful tool. We conducted a prospective on-site study to evaluate the diagnostic accuracy of the LFD with the straw sampling method compared with that of the dFAT with the skull opening procedure for post-mortem canine rabies diagnosis. We collected 97 rabies-suspected animals between December 1, 2020 and March 31, 2021. Among the 97 samples, 53 and 50 cases were positive tests for dFAT and LFD, respectively. The sensitivity and specificity of LFD with straw sampling method were 94.3% (95% confidence interval [CI], 84.3-98.8%) and 100% (95% CI, 92.0-100%), respectively. The performance of LFD by the straw sampling method showed relatively high sensitivity and 100% specificity compared with that of dFAT performed on samples collected after opening the skull. This methodology can be beneficial and is a strong tool to overcome limited animal surveillance in remote areas. However, because of our limited sample size, more data using fresh samples on-site and the optimizations are urgently needed for the further implementation in endemic areas.

Development of a Kit for Rapid Immunochromatographic Detection of Sacbrood Virus Infecting Apis cerana (AcSBV) Based on Polyclonal and Monoclonal Antibodies Raised against Recombinant VP1 and VP2 Expressed in Escherichia coli

A Korean isolate of the sacbrood virus infecting Apis cerana (AcSBV-Kor) is the most destructive honeybee virus, causing serious economic damage losses in Korean apiculture. To address this, here, we attempted to develop an assay for the rapid detection of AcSBV-Kor based on immunochromatographic detection of constituent viral proteins. Genes encoding VP1 and VP2 proteins of AcSBV-Kor were cloned into an expression vector (pET-28a) and expressed in Escherichia coli BL21(DE3). During purification, recombinant VP1 (rVP1) and VP2 (rVP2) proteins were found in the insoluble fraction, with a molecular size of 26.7 and 24.9 kDa, respectively. BALB/c mice immunized with the purified rVP1 and rVP2 produced polyclonal antibodies (pAbs) such as pAb-rVP1 and pAb-rVP2. Western blot analysis showed that pAb-rVP1 strongly reacted with the homologous rVP1 but weakly reacted with heterologous rVP2. However, pAb-rVP2 strongly reacted not only with the homologous rVP2 but also with the heterologous rVP1. Spleen cells of the immunized mice fused with SP2/0-Ag14 myeloma cells produced monoclonal antibodies (mAbs) such as mAb-rVP1-1 and mAb-rVP2-13. Western blot analysis indicated that pAb-rVP1, pAb-rVP2, mAb-rVP1-1, and mAb-rVP2-13 reacted with AcSBV-infected honeybees and larvae as well as the corresponding recombinant proteins. These antibodies were then used in the development of a rapid immunochromatography (IC) strip assay kit with colloidal gold coupled to pAb-rVP1 and pAb-rVP2 at the conjugate pad and mAb-rVP1-1 and mAb-rVP2-13 at the test line. One antibody pair, pAb-rVP1/mAb-VP1-1, showed positive reactivity as low as 1.38 × 10³ copies, while the other pair, pAb-rVP2/mAb-VP2-13, showed positive reactivity as low as 1.38 × 10⁴ copies. Therefore, the antibody pair pAb-rVP1/mAb-VP1-1 was selected as a final candidate for validation. To validate the detection of AcSBV, the IC strip tests were conducted with 50 positive and 50 negative samples and compared with real-time PCR tests. The results confirm that the developed IC assay is a sufficiently sensitive and specific detection method for user-friendly and rapid detection of AcSBV.

Eliminating dog-mediated rabies: challenges and strategies

Rabies is an acute encephalitis caused by a lyssavirus. It is primarily transmitted through bites of infected dogs which results in the worldwide death of an estimated 59000 humans every year. The disease is preventable through the application of post-exposure prophylaxis (PEP) and its elimination has been demonstrated in many countries by applying multiple interventions simultaneously. Nonetheless, rabies is still widespread in many developing countries, primarily due to the poor implementation of intervention strategies that include inadequate dog-bite wound management practices, unavailability/unaffordability of PEP by the communities, failure to control the disease in free-roaming dogs and wildlife, improper dog population management, weak surveillance and diagnostic facilities and a lack of a One Health approach to the disease. In this review, strategies to control dog-mediated rabies through a One Health approach were discussed. We recommend applying multiple interventions against the disease by involving all the concerned stakeholders in selected urban and rural areas of the countries where rabies is endemic. An empirical demonstration of disease freedom in the selected areas through a One Health approach is needed to convince policymakers to invest in rabies prevention and control on the national level. This multifaceted One Health control model will enhance the likelihood of achieving the goal of global rabies eradication by 2030.

Rabies virus in slaughtered dogs for meat consumption in Ghana: A potential risk for rabies transmission

Dog-mediated rabies is responsible for approximately 60,000 human deaths annually worldwide. Although dog slaughter for human consumption and its potential risk for rabies transmission has been reported, mainly in some parts of Western Africa and South-East Asia, more information on this and factors that influence dog meat consumption is required for a better understanding from places like Ghana where the practice is common. We tested 144 brain tissues from apparently healthy dogs slaughtered for human consumption for the presence of rabies viruses using a Lyssavirus-specific real-Time RT-PCR. Positive samples were confirmed by virus genome sequencing. We also administered questionnaires to 541 dog owners from three regions in Ghana and evaluated factors that could influence dog meat consumption. We interacted with butchers and observed slaughtering and meat preparation procedures. Three out of 144 (2.1%) brain tissues from apparently healthy dogs tested positive for rabies virus RNA. Two of the viruses with complete genomes were distinct from one another, but both belonged to the Africa 2 lineage. The third virus with a partial genome fragment had high sequence identity to the other two and also belonged to the Africa 2 lineage. Almost half of the study participants practiced dog consumption [49% (265/541)]. Males were almost twice (cOR = 1.72, 95% CI (1.17-2.52), p-value = .006) as likely to consume dog meat compared to females. Likewise, the Frafra tribe from northern Ghana [cOR = 825.1, 95% CI (185.3-3672.9), p-value < .0001] and those with non-specific tribes [cOR = 47.05, 95% CI (10.18-217.41), p-value < .0001] presented with higher odds of dog consumption compared to Ewes. The butchers used bare hands in meat preparation. This study demonstrates the presence of rabies virus RNA in apparently healthy dogs slaughtered for human consumption in Ghana and suggests a potential risk for rabies transmission. Veterinary departments and local assemblies are recommended to monitor and regulate this practice.

Human rabies: prospects for elimination

Almost half of all countries in the world are effectively free of human deaths from dog-mediated rabies. But the disease still affects people in low- and middle-income countries, especially the rural poor, and children. Successful regional elimination of human rabies is attributable to advances in significant and sustained investment in dog vaccination, post-exposure vaccination and surveillance, illustrated by productive efforts to reduce human rabies in Latin America over the last 35 years. Nonetheless, countries still facing endemic rabies face significant barriers to elimination. Using the 2017 Global Strategic Plan to end human rabies deaths from dog-mediated rabies by 2030 as a reference point and an organizing framework, we assess progress toward global rabies elimination by examining the characteristics of successful regional control efforts and barriers to elimination. Although substantive barriers exist for countries where rabies remains endemic, advances in knowledge, technology, institutions, and economics provide a basis for optimism.

Evaluation of the diagnostic accuracy of lateral flow devices as a tool to diagnose rabies in post-mortem animals

Implementation of lateral flow devices (LFDs) for rabies antigen detection is expected to improve surveillance through the efficient detection of rabid animals in resource-limited settings; however, the use of LFDs for diagnosis remains controversial because some commercially available kits show low sensitivity. Therefore, we compared the diagnostic efficacy of three LFDs (ADTEC, Bionote, and Elabscience kits) paralleled with the direct fluorescent antibody test (dFAT) using fresh samples and investigated the diagnostic accuracies. To do so, we evaluated rabies-suspected samples submitted to the Regional Animal Disease Diagnostic Laboratory III, Philippines. Furthermore, we conducted real-time RT-PCR and sequencing to measure the accuracy of field laboratory diagnosis. The total number of animals submitted during this study period was 184 cases, including negative control samples. Of these, 53.9% (84 cases) were positive in the dFAT. Dogs were the most common rabies-suspected animal (n = 135). The sensitivities of the ADTEC and Bionote kits were 0.88 (74 cases) and 0.95 (80 cases), respectively. The specificity of both kits was 1.00 (100 cases). Furthermore, the sensitivity and specificity of the ADTEC kit after directly homogenizing the samples in assay buffer without dilution in phosphate-buffered saline (ADTEC kit DM) were 0.94 (79 cases) and 1.00 (100 cases), respectively. By contrast, there were no positive results using the Elabscience kit among all dFAT-positive samples. The sensitivity and specificity of LFDs make these tests highly feasible if properly used. Therefore, LFD tests can be used to strengthen the surveillance of rabies-infected animals in endemic and resource-limited settings.

Evaluation of a rapid immunochromatographic test kit to the gold standard fluorescent antibody test for diagnosis of rabies in animals in Bhutan

Background

Rabies kills approximately 59,000 people each year worldwide. Rapid and accurate diagnosis of rabies is important for instituting rapid containment measures and for advising the exposed people for postexposure treatment. The application of a rapid diagnostic tests in the field can greatly enhance disease surveillance and diagnostic activities, especially in resource poor settings. In this study, a total of 179 brain tissue samples collected from different rabies suspect animal species (113 dogs, 50 cattle, 10 cats, 3 goats, 2 horses, and 1 bear) were selected and tested using both rapid immunochromatographic kit and the reference standard fluorescent antibody test (FAT). We evaluated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of a rapid antigen detection test kit produced by BioNote, Inc. (Hwaseong-si, Korea) relative to a FAT for its fit-for-purpose for confirmation of clinical cases of rabies for early response and enhancing rabies surveillance.

Results

Among 179 samples examined in this study, there was a concordance in results by the rapid test and FAT in 115 positive samples and 54 negative samples. Test results were discordant in 10 samples which were positive by FAT, but negative (false negative) by rapid kit. The rapid test kit showed a sensitivity of 92% (95% CI: 85.9–95.6) and specificity of 100% (95% CI: 93.4–100) using FAT as the reference standard. The positive and negative predictive values were found to be 100% (95% CI:96.7–100) and 84.4% (95% CI: 73.6–91.3), respectively. Overall, there was 94.4% (95% CI: 90–96.9) test agreement between rapid test and FAT (Kappa value = 0.874) with a positive percent agreement and negative percent agreement of 92 and 100%, respectively.

Conclusions

Our finding demonstrated that the rapid test kit (BioNote) can be used for rabies surveillance and confirming clinical case of rabies in animals for making rapid decisions particularly controlling rabies outbreaks in resource poor settings.

Reaching the zero by 30 dog-mediated human rabies goal

It is unacceptable that as we advance into the 21st century rabies is still a threat to humans and animals alike. Given public health interventions that focus solely on disease prevention in humans have no effect on the reduction of infection in the reservoir hosts, the most effective way to combat human rabies infection is to control the disease transmission by mass vaccination of the animal source, e.g. dogs and wildlife1. This short communication focuses on the global strategic target to end human deaths from dog-mediated rabies by 20302 in line with the Sustainable Development Goals by providing recent updates on World Health Organization (WHO) and OIE guidelines3–5 and recommendations as well as highlighting Australian rabies research activities to prevent an incursion of rabies into the country.