Development of harmonised schemes for monitoring and reporting of rabies in animals in the European Union

A Global Perspective on Oral Vaccination of Wildlife against Rabies

The long-term mitigation of human-domestic animal-wildlife conflicts is complex and difficult. Over the last 50 yr, the primary biomedical concepts and actualized collaborative global field applications of oral rabies vaccination to wildlife serve as one dramatic example that revolutionized the field of infectious disease management of free-ranging animals. Oral vaccination of wildlife occurred in diverse locales within Africa, Eurasia, the Middle East, and North America. Although rabies is not a candidate for eradication, over a billion doses of vaccine-laden baits distributed strategically by hand, at baiting stations, or via aircraft, resulted in widespread disease prevention, control, or local disease elimination among mesocarnivores. Pure, potent, safe, and efficacious vaccines consisted of either modified-live, highly attenuated, or recombinant viruses contained within attractive, edible baits. Since the late 1970s, major free-ranging target species have included coyotes (Canis latrans), foxes (Urocyon cinereoargenteus; Vulpes vulpes), jackals (Canis aureus; Lupulella mesomelas), raccoons (Procyon lotor), raccoon dogs (Nyctereutes procyonoides), and skunks (Mephitis mephitis). Operational progress has occurred in all but the latter species. Programmatic evaluations of oral rabies vaccination success have included: demonstration of biomarkers incorporated within vaccine-laden baits in target species as representative of bait contact; serological measurement of the induction of specific rabies virus neutralizing antibodies, indicative of an immune response to vaccine; and most importantly, the decreasing detection of rabies virus antigens in the brains of collected animals via enhanced laboratory-based surveillance, as evidence of management impact. Although often conceived mistakenly as a panacea, such cost-effective technology applied to free-ranging wildlife represents a real-world, One Health application benefiting agriculture, conservation biology, and public health. Based upon lessons learned with oral rabies vaccination of mesocarnivores, opportunities for future extension to other taxa and additional diseases will have far-reaching, transdisciplinary benefits.

Retrospective analysis of sero-prevalence and bait uptake estimations in foxes after oral rabies vaccination programmes at European level: Lessons learned and paths forward

Rabies caused by the Classical Rabies Virus (Lyssavirus rabies abbreviated RABV) in the European Union has been close to elimination mainly thanks to Oral Rabies Vaccination (ORV) campaigns targeting wildlife (primarily red foxes). ORV programmes co-financed by the European Commission include a monitoring-component to assess the effectiveness of the ORV campaigns at national level. This assessment is performed by a random collection of red foxes in the vaccinated areas with control of antibodies presence by serological analysis and control of bait uptake by detection of biomarkers (tetracycline incorporated into the baits) in the bones and teeth. ORV programmes aim to a vaccine coverage high enough to immunize (ideally) 70 % of the reservoir population to control the spread of the disease. European Union (EU) programmes that led to almost elimination of rabies on the territory have been traditionally found to have a bait uptake average of 70 % (EU countries; 2010-2020 period) while the seroconversion data showed an average level of 40 % (EU countries; 2010-2020 period). To better understand variations of these indicators, a study was been set up to evaluate the impact of several variables (linked to the vaccination programme itself and linked to environmental conditions) on the bait uptake and the seroconversion rate. Thus, pooling data from several countries provides more powerful statistics and the highest probability of detecting trends. Results of this study advocate the use of a single serological test across the EU since data variation due to the type of test used was higher than variations due to field factors, making the interpretation of monitoring results at EU level challenging. In addition, the results indicates a negative correlation between bait uptake and maximum temperatures reached during ORV campaigns questioning the potential impact of climatic change and associated increase of temperatures on the ORV programmes efficiency. Several hypotheses requesting additional investigation are drawn and discussed in this paper.

The European Union One Health 2020 Zoonoses Report

This report of the EFSA and the European Centre for Disease Prevention and Control presents the results of zoonoses monitoring activities carried out in 2020 in 27 EU Member States (MS) and nine non-MS. Key statistics on zoonoses and zoonotic agents in humans, food, animals and feed are provided and interpreted historically. Two events impacted 2020 MS data collection and related statistics: the Coronavirus Disease 2019 (COVID-19) pandemic and the withdrawal of the United Kingdom from the EU. In 2020, the first and second most reported zoonoses in humans were campylobacteriosis and salmonellosis, respectively. The EU trend for confirmed human cases of these two diseases was stable (flat) from 2016 to 2020. Fourteen of the 26 MS reporting data on Salmonella control programmes in poultry met the reduction targets for all poultry categories. Salmonella results for carcases of various species performed by competent authorities were more frequently positive than own-checks conducted by food business operators. This was also the case for Campylobacter quantification results from broiler carcases for the MS group that submitted data from both samplers, whereas overall at EU level, those percentages were comparable. Yersiniosis was the third most reported zoonosis in humans, with 10-fold less cases reported than salmonellosis, followed by Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes infections. Illnesses caused by L. monocytogenes and West Nile virus infections were the most severe zoonotic diseases with the highest case fatality. In 2020, 27 MS reported 3,086 foodborne outbreaks (a 47.0% decrease from 2019) and 20,017 human cases (a 61.3% decrease). Salmonella remained the most frequently reported causative agent for foodborne outbreaks. Salmonella in 'eggs and egg products', norovirus in 'crustaceans, shellfish, molluscs and products containing them' and L. monocytogenes in 'fish and fish products' were the agent/food pairs of most concern. This report also provides updates on tuberculosis due to Mycobacterium bovis or Mycobacterium caprae, Brucella, Trichinella, Echinococcus, Toxoplasma, rabies, Coxiella burnetii (Q fever) and tularaemia.

Spillover of West Caucasian Bat Lyssavirus (WCBV) in a Domestic Cat and Westward Expansion in the Palearctic Region

In June 2020, a cat from Arezzo (Italy) that died from a neurological disease was diagnosed with West Caucasian Bat Lyssavirus (WCBV). The virus retained high identity across the whole-genome with the reference isolate found in 2002 from a Russian bent-winged bat. We applied control measures recommended by national regulations, investigated a possible interface between cats and bats using visual inspections, bioacoustics analyses and camera trapping and performed active and passive surveillance in bats to trace the source of infection. People that were exposed to the cat received full post-exposure prophylaxis while animals underwent six months of quarantine. One year later, they are all healthy. In a tunnel located near the cat’s house, we identified a group of bent-winged bats that showed virus-neutralizing antibodies to WCBV across four sampling occasions, but no virus in salivary swabs. Carcasses from other bat species were all negative. This description of WCBV in a non-flying mammal confirms that this virus can cause clinical rabies in the absence of preventive and therapeutic measures, and highlights the lack of international guidelines against divergent lyssaviruses. We detected bent-winged bats as the most probable source of infection, testifying the encroachment between these bats and pets/human in urban areas and confirming free-ranging cats as potential hazard for public health and conservation.

Current Status of Rabies and Its Eradication in Eastern and Southeastern Europe

The objective of this paper is to provide an overview of the current status of rabies in Europe, with special emphasis on Croatia and Southeast and East Europe. Due to the systematic implementation of a rabies eradication program by oral vaccination of wild animals, by the end of the 20th century, most West and Central European countries were rabies-free. The EU goal was to eradicate rabies in wildlife and domestic animals by 2020. No matter how achievable the goal seemed to be, the disease is still present in the eastern part of the EU, as was notified in 2020 by two member states—Poland and Romania. Croatia has been rabies-free for the last seven years but given that it borders a non-EU country in which a case of rabies was confirmed in 2020, it will continue to contribute to the maintenance of the rabies-free region. A rabies-free EU can only be achieved by continuous oral vaccination, coordination and a regional approach. The prevention of reintroductions from bordering countries in which rabies has not been eradicated yet, and the support for the eradication efforts made by these countries, are goals still pending.

The European Union One Health 2019 Zoonoses Report

This report of the EFSA and the European Centre for Disease Prevention and Control presents the results of zoonoses monitoring activities carried out in 2019 in 36 European countries (28 Member States (MS) and eight non-MS). The first and second most reported zoonoses in humans were campylobacteriosis and salmonellosis, respectively. The EU trend for confirmed human cases of these two diseases was stable (flat) during 2015-2019. The proportion of human salmonellosis cases due to Salmonella Enteritidis acquired in the EU was similar to that in 2017-2018. Of the 26 MS reporting on Salmonella control programmes in poultry, 18 met the reduction targets, whereas eight failed to meet at least one. The EU prevalence of Salmonella target serovar-positive flocks has been stable since 2015 for breeding hens, laying hens, broilers and fattening turkeys, with fluctuations for breeding turkey flocks. Salmonella results from competent authorities for pig carcases and for poultry tested through national control programmes were more frequently positive than those from food business operators. Shiga toxin-producing Escherichia coli (STEC) infection was the third most reported zoonosis in humans and increased from 2015 to 2019. Yersiniosis was the fourth most reported zoonosis in humans in 2019 with a stable trend in 2015-2019. The EU trend of confirmed listeriosis cases remained stable in 2015-2019 after a long period of increase. Listeria rarely exceeded the EU food safety limit tested in ready-to-eat food. In total, 5,175 food-borne outbreaks were reported. Salmonella remained the most detected agent but the number of outbreaks due to S. Enteritidis decreased. Norovirus in fish and fishery products was the agent/food pair causing the highest number of strong-evidence outbreaks. The report provides further updates on bovine tuberculosis, Brucella, Trichinella, Echinococcus, Toxoplasma, rabies, West Nile virus, Coxiella burnetii (Q fever) and tularaemia.

A metagenomic glimpse into the gut of wild and domestic animals: Quantification of antimicrobial resistance and more

Antimicrobial resistance (AMR) in bacteria is a complex subject, why one need to look at this phenomenon from a wider and holistic perspective. The extensive use of the same antimicrobial classes in human and veterinary medicine as well as horticulture is one of the main drivers for the AMR selection. Here, we applied shotgun metagenomics to investigate the AMR epidemiology in several animal species including farm animals, which are often exposed to antimicrobial treatment opposed to an unique set of wild animals that seems not to be subjected to antimicrobial pressure. The comparison of the domestic and wild animals allowed to investigate the possible anthropogenic impact on AMR spread. Inclusion of animals with different feeding behaviors (carnivores, omnivores) enabled to further assess which AMR genes that thrives within the food chain. We tested fecal samples not only of intensively produced chickens, turkeys, and pigs, but also of wild animals such as wild boars, red foxes, and rodents. A multi-directional approach mapping obtained sequences to several databases provided insight into the occurrence of the different AMR genes. The method applied enabled also analysis of other factors that may influence AMR of intestinal microbiome such as diet. Our findings confirmed higher levels of AMR in farm animals than in wildlife. The results also revealed the potential of wildlife in the AMR dissemination. Particularly in red foxes, we found evidence of several AMR genes conferring resistance to critically important antimicrobials like quinolones and cephalosporins. In contrast, the lowest abundance of AMR was observed in rodents originating from natural environment with presumed limited exposure to antimicrobials. Shotgun metagenomics enabled us to demonstrate that discrepancies between AMR profiles found in the intestinal microbiome of various animals probably resulted from the different antimicrobial exposure, habitats, and behavior of the tested animal species.

Zero Endemic Cases of Wildlife Rabies (Classical Rabies Virus, RABV) in the European Union by 2020: An Achievable Goal

The elimination of rabies transmitted by Classical Rabies Virus (RABV) in the European Union (EU) is now in sight. Scientific advances have made it possible to develop oral vaccination for wildlife by incorporating rabies vaccines in baits for foxes. At the start of the 1980s, aerial distribution of vaccine baits was tested and found to be a promising tool. The EU identified rabies elimination as a priority, and provided considerable financial and technical resources to the infected EU Member States, allowing regular and large-scale rabies eradication programs based on aerial vaccination. The EU also provides support to non-EU countries in its eastern and south eastern borders. The key elements of the rabies eradication programs are oral rabies vaccination (ORV), quality control of vaccines and control of their distribution, rabies surveillance and monitoring of the vaccination effectiveness. EU Member States and non-EU countries with EU funded eradication programs counted on the technical support of the rabies subgroup of the Task Force for monitoring disease eradication and of the EU Reference Laboratory (EURL) for rabies. In 2018, eight rabies cases induced by classical rabies virus RABV (six in wild animals and two in domestic animals) were detected in three EU Member States, representing a sharp decrease compared to the situation in 2010, where there were more than 1500 cases in nine EU Member States. The goal is to reach zero cases in wildlife and domestic animals in the EU by 2020, a target that now seems achievable.

Control and elimination of rabies in Croatia

Despite the implementation of control measures (preventive dog vaccination), rabies has become endemic in Croatia, with red foxes being the main reservoir species. Oral rabies vaccination (ORV) campaigns supported by the European Commission have been conducted twice a year since the spring of 2011. The first campaigns were limited to the northern and eastern parts of the country, and from the autumn of 2012, the program was extended to the entire country. The Lysvulpen vaccine containing the SAD Bern strain was used for ORV. Following the vaccination campaigns, the number of rabies cases decreased, and the last positive case was recorded in February 2014. The bait uptake ranged from 24.86% to 84.62% and the immunisation rate from 11.24% to 35.64%.

Bokeloh bat lyssavirus isolation in a Natterer's bat, Poland

In recent years, Bokeloh bat lyssavirus (BBLV), a member of the novel lyssavirus genus Bokeloh bat lyssavirus in the family Rhabdoviridae, has been detected in Germany (five cases) and France (two cases). Here, we report the isolation of BBLV in a Natterer's bat (Myotis nattereri) in Poland. The bat brain tested positive for rabies using classical diagnostics tests (FAT and RTCIT) and then subsequently confirmed by molecular techniques. Viral RNA was found in all peripheral organs tested, and the highest viral loads were detected in brain, the salivary gland and bladder. Phylogenetic analysis performed on complete viral genome sequences revealed the closest homology to representatives of BBLV lineage B, isolated previously in southern Germany. This case provides further evidence that BBLV is widespread in Europe.

Evaluation of Enzyme Linked Immuno-Sorbent Assay and Rapid Immuno-Diagnostic Test for Rabies Antigen Detection in Archived Dog Brain Tissues

Rabies urgently requires strengthening of new and existing diagnostic methodology in order to overcome the threat it poses. We evaluated the Enzyme Linked Immuno-Sorbent Assay (ELISA) and the Rapid Immunodiagnostic Test (RIDT) in detecting rabies viral antigens, comparing both tests with the Direct Fluorescent Antibody Test (DFAT) which is the gold standard in rabies diagnosis. Fifty dog brain tissues collected from the archives of the Central Diagnostic Laboratory, National Veterinary Research Institute, Vom, Nigeria, were utilized for this study. ELISA performed better than RIDT and recorded equivalent result with DFAT as compared with RIDT. There was a 96 % agreement between ELISA and DFAT for rabies antigen detection (concordance coefficient 78 % : 95 % C. I. 0.6366 to 0.8654) while there was a 54 % agreement between RIDT and DFAT (concordance coefficient 17 % : 95 % C. I. 0.05138—0.2752). Compared to DFAT, the sensitivities of ELISA and RIDT were 95.5 % and 47.6 %, respectively, and the specificities of ELISA and RIDT were 100 % and 87.5 % respectively. The simple Cohen’s kappa coefficient for ELISA related to the DFAT was found to be 0.834 (95 % C. I. 0.613—1.0). For RIDT, the Kappa value was 0.170 (95 % C. I. 0.003—0.337). The ELISA is as reliable a diagnostic method as the DFAT which is the gold standard for rabies diagnosis. It has an advantage of being able to analyse large number of samples at the same time, making it more suitable for epidemiological studies and for laboratories that cannot perform the DFAT. The unsatisfactory result of RIDT in this study reiterates the need to perform an adequate test validation before it can be used in the laboratory for rabies diagnosis.

An inter- laboratory proficiency testing exercise for rabies diagnosis in Latin America and the Caribbean

The direct fluorescent antibody test (DFA), is performed in all rabies reference laboratories across Latin America and the Caribbean (LAC). Despite DFA being a critical capacity in the control of rabies, there is not a standardized protocol in the region. We describe the results of the first inter-laboratory proficiency exercise of national rabies laboratories in LAC countries as part of the regional efforts towards dog-maintained rabies elimination in the American region. Twenty three laboratories affiliated to the Ministries of Health and Ministries of Agriculture participated in this exercise. In addition, the laboratories completed an online questionnaire to assess laboratory practices. Answers to the online questionnaire indicated large variability in the laboratories throughput, equipment used, protocols availability, quality control standards and biosafety requirements. Our results will inform actions to improve and harmonize laboratory rabies capacities across LAC in support for the regional efforts towards elimination of dog-maintained rabies.

Evaluation of ELISA for the detection of rabies virus antibodies from the thoracic liquid and muscle extract samples in the monitoring of fox oral vaccination campaigns

BACKGROUND

The main goal of oral vaccination of foxes is eradication of rabies in the red fox population as rabies reservoirs. To evaluate the success of vaccination a serological testing is conducted as a part of monitoring program. Two different methods are used regarding rabies serology: virus neutralisation test and ELISA.

METHODS

In this study the reliability of BioPro ELISA was evaluated for testing haemolytic thoracic liquids and muscle extracts originated from 147 foxes in comparison to mFAVN. Also, the influence of heat treatment of samples on test results was investigated.

RESULTS

The specificity of the test for not-heat treated samples was 92.98% and sensitivity 79.20%. Diagnostic validity of the ELISA compared to the mFAVN test when not-heat treated samples were used was 89.16%. The specificity of the test for heat treated samples was 79.10% and sensitivity 96.36%. Diagnostic validity of the BioPro ELISA compared to the mFAVN test for heat treated samples was 94.30%.

CONCLUSION

According to this study, the BioPro ELISA is reliable tool for detection of rabies specific antibodies in the context of evaluation of oral vaccination of foxes from poor quality samples as a substitution for virus neutralisation tests.

Evaluation of the first oral rabies vaccination campaign of the red foxes in Greece

Following the late 2012 recurrence of rabies in wild foxes (Vulpes vulpes) in central and north-western Greece, the first oral fox vaccination campaign co-financed by the European Union (EU) and the Greek state budget, was implemented. Initially, it involved 24 regional units of the Greek territory during the period October-December 2013. Vaccine-baits were aerially distributed by fixed-wing aircrafts. Vaccines were scattered along parallel flight paths 500m apart in order to optimize aerial missions and achieve homogeneous distribution. A geographical information system was used to objectively evaluate bait distribution. This system identified areas of inadequate bait density that would require additional flights. A total number of 1,504,821 baits were distributed covering an area of 54,584.29km(2). To assess the effectiveness of oral vaccination campaign a monitoring program was introduced, which entailed examination of serum samples and canine teeth derived from red foxes collected in the field. The laboratory analysis revealed 60% seropositivity and detection of tetracycline biomarker in 70% of the foxes tested.

Sylvatic rabies epidemic in Italy: implementation of a data management system to assess the level of application of preventive dog vaccination

After 20 years of absence, rabies re-emerged in wild animals in north-eastern Italy in October 2008. Besides measures undertaken to fight the spread of infection in wildlife, vaccination against rabies was made compulsory for dogs living in the risk area. In the last 15 years, the veterinary authorities have focused on implementing computerized data collection systems in animal health, to serve as working tools for epidemiological surveillance activities and emergencies management. The prerequisite for implementing any data collection system is knowledge of the animal population. This also applies to the Canine Registry Data Bank, in which data on dogs and their movements, together with personal data on each owner and keeper, have been stored since 2003. The management information system has been updated and specific functions have been integrated in order to support the activity of both the veterinary services and the veterinary practitioners involved in the dog vaccination program. Vaccination became voluntary in February 2013. This paper describes implementation of the software and organization of data gathering, highlighting the benefits of computerized data compared to previously used paper-based data collection systems. The new functions, designed to centralize collection of uniform, updated vaccination data, have led to more efficient organization and better control of the vaccination plan. Automated information processing allowed vaccination operations to be supervised, incurred costs to be calculated, and vaccination coverage of the dog population to be monitored during the 3 years of compulsory vaccination.

Bat rabies in France: a 24-year retrospective epidemiological study

Since bat rabies surveillance was first implemented in France in 1989, 48 autochthonous rabies cases without human contamination have been reported using routine diagnosis methods. In this retrospective study, data on bats submitted for rabies testing were analysed in order to better understand the epidemiology of EBLV-1 in bats in France and to investigate some epidemiological trends. Of the 3176 bats submitted for rabies diagnosis from 1989 to 2013, 1.96% (48/2447 analysed) were diagnosed positive. Among the twelve recognised virus species within the Lyssavirus genus, two species were isolated in France. 47 positive bats were morphologically identified as Eptesicus serotinus and were shown to be infected by both the EBLV-1a and the EBLV-1b lineages. Isolation of BBLV in Myotis nattereri was reported once in the north-east of France in 2012. The phylogenetic characterisation of all 47 French EBLV-1 isolates sampled between 1989 and 2013 and the French BBLV sample against 21 referenced partial nucleoprotein sequences confirmed the low genetic diversity of EBLV-1 despite its extensive geographical range. Statistical analysis performed on the serotine bat data collected from 1989 to 2013 showed seasonal variation of rabies occurrence with a significantly higher proportion of positive samples detected during the autumn compared to the spring and the summer period (34% of positive bats detected in autumn, 15% in summer, 13% in spring and 12% in winter). In this study, we have provided the details of the geographical distribution of EBLV-1a in the south-west of France and the north-south division of EBLV-1b with its subdivisions into three phylogenetic groups: group B1 in the north-west, group B2 in the centre and group B3 in the north-east of France.

Rabies in Europe: what are the risks?

Rabies remains a serious endemic disease in animal populations in many European countries. Oral vaccination by use of rabies vaccine baits has proved to be durably efficient for controlling and eliminating terrestrial rabies. However, the recurrence of rabies in some countries highlights the fragility of rabies-free country status and the need for continuous surveillance. In Eastern and Southern countries, the rabies control programmes for foxes should be accompanied by stray dog management measures in view of the high populations of strays in certain areas. Alerts of rabies in pets imported from enzootic countries are regularly reported in Europe, threatening the rabies-free status of terrestrial animals. New variants of rabies virus have been recently discovered in autochthonous bats, implying research studies to assess the efficacy of the current vaccines against those strains and the possible crossing of the species barrier in terrestrial mammals. The incidence of the disease in humans is very low, with cases contracted in Europe or in enzootic countries. Sustainable strategies of vaccination programmes in animals and improvement of public awareness, particularly for travelers, regarding rabies risks and legislation for pet movements would render accessible the elimination of rabies in Europe.

Epidemiology and molecular diversity of rabies viruses in Bulgaria

A health emergency situation occurred in Bulgaria in 2007 when positive rabies cases were notified in Sofia district in the central-western part of the country, suggesting a southward spread of the disease for the first time in the last 10 years. Phylogenetic analysis on 49 isolates sampled between 2009 and 2011 showed, for the first time, evidence of the existence of NEE and D clustered lineages in Bulgaria. Their geographical distribution clearly reveals the permeability of natural barriers, as already suggested by the disease spread that occurred across the Balkan mountain range in 2007. The monitoring and passive surveillance programmes conducted since the first 2009 oral vaccination campaign, the spatio-temporal evolution of the disease in the country since 2007, and the need for further investigation of the role of jackals in virus dispersion are discussed.

First isolation of a rabid bat infected with European bat lyssavirus in Luxembourg

Rabid bats are regularly reported in Europe, especially in countries that have implemented a bat surveillance network. In May 2013, bat rabies was evidenced for the first time in Luxembourg (southern city of Differdange). The rabies virus, an EBLV-1b strain, was diagnosed in a serotine bat that bit a 29-year-old male person while he was asleep. The man received rapidly a post-exposure RABV treatment and was put under strict medical supervision.

The elimination of fox rabies from Europe: determinants of success and lessons for the future

Despite perceived challenges to controlling an infectious disease in wildlife, oral rabies vaccination (ORV) of foxes has proved a remarkably successful tool and a prime example of a sophisticated strategy to eliminate disease from wildlife reservoirs. During the past three decades, the implementation of ORV programmes in 24 countries has led to the elimination of fox-mediated rabies from vast areas of Western and Central Europe. In this study, we evaluated the efficiency of 22 European ORV programmes between 1978 and 2010. During this period an area of almost 1.9 million km² was targeted at least once with vaccine baits, with control taking between 5 and 26 years depending upon the country. We examined factors influencing effort required both to control and eliminate fox rabies as well as cost-related issues of these programmes. The proportion of land area ever affected by rabies and an index capturing the size and overlap of successive ORV campaigns were identified as factors having statistically significant effects on the number of campaigns required to both control and eliminate rabies. Repeat comprehensive campaigns that are wholly overlapping much more rapidly eliminate infection and are less costly in the long term. Disproportionally greater effort is required in the final phase of an ORV programme, with a median of 11 additional campaigns required to eliminate disease once incidence has been reduced by 90 per cent. If successive ORV campaigns span the entire affected area, rabies will be eliminated more rapidly than if campaigns are implemented in a less comprehensive manner, therefore reducing ORV expenditure in the longer term. These findings should help improve the planning and implementation of ORV programmes, and facilitate future decision-making by veterinary authorities and policy-makers.

Comparative assay of fluorescent antibody test results among twelve European National Reference Laboratories using various anti-rabies conjugates

Twelve National Reference Laboratories (NRLs) for rabies have undertaken a comparative assay to assess the comparison of fluorescent antibody test (FAT) results using five coded commercial anti-rabies conjugates (Biorad, Bioveta, Fujirebio, Millipore, and SIFIN conjugates). Homogenized positive brain tissues infected with various lyssavirus species as well as negative samples were analyzed blindly using a standardized FAT procedure. Conjugates B, C, D, and E were found to be significantly more effective than conjugate A for GS7 (French RABV) diluted samples (1/8 and 1/100) while the frequency of concordant results of conjugates C and D differ significantly from conjugates A, B and E for CVS 27. For detection of EBLV-1 strains, conjugates C and D also presented a significantly lower frequency of discordant results compared to conjugates A, B and E. Conjugates B, C and D were found to be significantly more effective than conjugates E and A for EBLV-2 and ABLV samples. In view of these results, conjugates C and D set themselves apart from the others and appeared as the most effective of this 5-panel conjugates. This study clearly demonstrates that the variability of conjugates used by National Reference Laboratories can potentially lead to discordant results and influence assay sensitivity. In case of false negative results this could have a dramatic impact if the animal under investigation is responsible for human exposure. To avoid such situations, confirmatory tests should be implemented.

Bat Rabies

The lyssaviruses are a diverse group of viruses capable of causing rabies, which is an invariably fatal encephalitic disease in both humans and animals. Currently, the lyssavirus genus consists of 12 species with 11 of these distinct species having been isolated from bats. The basis for the apparent geographical segregation of bat lyssavirus infection between the Old and New World is poorly understood. In the New World species of insectivorous, frugivorous, and hematophagous bats, all represent important reservoirs of rabies virus. In contrast, rabies virus has never been detected in Old World bat populations, despite being endemic in terrestrial mammals. Instead, both insectivorous and frugivorous bat species across the Old World appear to act as reservoirs for the non-rabies lyssaviruses. In this chapter, we describe the association of the different lyssaviruses with different bat species across the world, classifying bat species by their feeding behavior.

Bat rabies surveillance in Europe

Rabies is the oldest known zoonotic disease and was also the first recognized bat associated infection in humans. To date, four different lyssavirus species are the causative agents of rabies in European bats: the European Bat Lyssaviruses type 1 and 2 (EBLV-1, EBLV-2), the recently discovered putative new lyssavirus species Bokeloh Bat Lyssavirus (BBLV) and the West Caucasian Bat Virus (WCBV). Unlike in the new world, bat rabies cases in Europe are comparatively less frequent, possibly as a result of varying intensity of surveillance. Thus, the objective was to provide an assessment of the bat rabies surveillance data in Europe, taking both reported data to the WHO Rabies Bulletin Europe and published results into account. In Europe, 959 bat rabies cases were reported to the RBE in the time period 1977-2010 with the vast majority characterized as EBLV-1, frequently isolated in the Netherlands, North Germany, Denmark, Poland and also in parts of France and Spain. Most EBLV-2 isolates originated from the United Kingdom (UK) and the Netherlands, and EBLV-2 was also detected in Germany, Finland and Switzerland. Thus far, only one isolate of BBLV was found in Germany. Published passive bat rabies surveillance comprised testing of 28 of the 52 different European bat species for rabies. EBLV-1 was isolated exclusively from Serotine bats (Eptesicus serotinus and Eptesicus isabellinus), while EBLV-2 was detected in 14 Daubenton's bats (Myotis daubentonii) and 5 Pond bats (Myotis dasycneme). A virus from a single Natterer's bat (Myotis nattereri) was characterized as BBLV. During active surveillance, only oral swabs from 2 Daubenton's bats (EBLV-2) and from several Eptesicus bats (EBLV-1) yielded virus positive RNA. Virus neutralizing antibodies against lyssaviruses were detected in various European bat species from different countries, and its value and implications are discussed.

Bat rabies, public health and European bat conservation

Most records of European bat lyssaviruses (EBLVs) are confined to three species - the serotine bat for EBLV1 (900 records) and Daubenton's bat and the pond bat for EBLV2 (25 records). High levels of seroprevalence, which may vary from year to year, are also recorded. All bat vectors of EBLVs are synanthropic, some exclusively so. Despite this, there have been only five cases of human rabies resulting from EBLV infection in the 590 million people of greater Europe during the last 35 years. These have triggered major programmes of surveillance in many European countries. The emphasis on active versus passive surveillance and the intensity with which they have been carried out has varied from country to country. Both involve cooperation between bat researchers, virologists and public health officials and the latter, in particular, engages amateur bat workers and members of the public. Bat NGOs throughout Europe have worked to persuade the public not to handle bats or to do so only with gloved hands and, in the case of bat workers, to receive pre-exposure immunization. They have also countered negative media coverage of bat rabies. Householders with bat roosts in their dwellings have in general been persuaded to retain their bats. Attempts have been made to persuade all European countries to establish comparable EBLV surveillance programmes. In the last 25 years, virologists, public health officials, bat biologists and conservationists, both amateur and professional have worked closely and collaboratively for the protection of the public and the conservation of bats, with little polarization of views.

Eliminating rabies in Estonia

The compulsory vaccination of pets, the recommended vaccination of farm animals in grazing areas and the extermination of stray animals did not succeed in eliminating rabies in Estonia because the virus was maintained in two main wildlife reservoirs, foxes and raccoon dogs. These two species became a priority target therefore in order to control rabies. Supported by the European Community, successive oral vaccination (OV) campaigns were conducted twice a year using Rabigen® SAG2 baits, beginning in autumn 2005 in North Estonia. They were then extended to the whole territory from spring 2006. Following the vaccination campaigns, the incidence of rabies cases dramatically decreased, with 266 cases in 2005, 114 in 2006, four in 2007 and three in 2008. Since March 2008, no rabies cases have been detected in Estonia other than three cases reported in summer 2009 and one case in January 2011, all in areas close to the South-Eastern border with Russia. The bait uptake was satisfactory, with tetracycline positivity rates ranging from 85% to 93% in foxes and from 82% to 88% in raccoon dogs. Immunisation rates evaluated by ELISA ranged from 34% to 55% in foxes and from 38% to 55% in raccoon dogs. The rabies situation in Estonia was compared to that of the other two Baltic States, Latvia and Lithuania. Despite regular OV campaigns conducted throughout their territory since 2006, and an improvement in the epidemiological situation, rabies has still not been eradicated in these countries. An analysis of the number of baits distributed and the funding allocated by the European Commission showed that the strategy for rabies control is more cost-effective in Estonia than in Latvia and Lithuania.

International interlaboratory trials on rabies diagnosis: an overview of results and variation in reference diagnosis techniques (fluorescent antibody test, rabies tissue culture infection test, mouse inoculation test) and molecular biology techniques

Interlaboratory trials on rabies diagnosis were organised in 2009 and in 2010 by the European Union Reference Laboratory (EURL) for rabies. In 2009, two panels of virus samples were sent to participating laboratories to compare results on reference diagnosis techniques and on RT-PCR. A single panel was sent in 2010 to test FAT (fluorescent antibody test), RTCIT (rabies tissue culture infection test) and RT-PCR techniques. The virus panels included the RABV, EBLV-1, EBLV-2 and ABLV strains. Results revealed that laboratories produced the highest proportion of concordant results using RT-PCR (90.5%) and FAT (87.1%), followed by RTCIT (70.0%) and MIT (35.0%) in 2009 and in FAT (85.0%) and RT-PCR (80.6%) followed by RTCIT (77.3%) in 2010. Errors were only observed in bat strains (i.e. none in the RABV strain) for the RT-PCR or FAT techniques, highlighting the need to improve diagnosis most specifically in such strains. RT-PCR was the technique showing the lowest rate of false negative results in either trial year, while RTCIT and MIT (performed in 2009 only) were the techniques with the lowest proportion of false positive results. Nevertheless, the FAT technique represented a good compromise with both satisfactory sensitivity and specificity, as only a few false positive (1.6% in 2009, 5.8% in 2010) and false negative results (1.6% in both 2009 and 2010) were detected. The analysis of technical questionnaires describing the protocols used by participating laboratories revealed variation in the methods used that may induce inconsistencies in the results. In this study, the number of readers for FAT slide examination was identified as a factor affecting significantly the results of laboratories, suggesting that two independent readers are necessary for routine rabies diagnosis. Our findings highlight the need for all rabies diagnostic laboratories to improve harmonisation of procedures.