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

Étude de la transmission d'Echinococcus multilocularis dans une grande agglomération : influence du comportement alimentaire et de l'utilisation de l'espace par le renard roux (Vulpes vulpes) sur la contamination de l'environnement.

Alveolar Echinococcosis is a lethal zoonosis transmitted to humans by the ingestion of eggs of the tænia Echinococcus multilocularis. The cycle of the parasite needs a carnivore as definitive host (mainly the red fox) and the common and water voles (Microtus arvalis and Arvicola terrestris) as intermediate hosts. Since 20 years, the more and more common observations of urban foxes gave rise to many questions about the possible increased risk of transmission to man due to the proximity of foxes. Recent studies showed the presence of E. multilocularis in urban foxes with variable prevalence. However, the conditions of the development of this parasite in the urbanized area are few documented. Work presented here proposes to improve comprehension of the cycle of E. multilocularis in such urbanized area. A monitoring of the red fox infection by collection of road kills or trapped animals highlighted a "rural to urban" decreasing gradient of infection. Along this gradient, different habitats were regularly sampled; this study showed the importance for the red fox of the availability of Microtus sp. in waste land landscape. The study of the adaptation of its diet by red fox to the variations of rodents densities showed that the Microtus sp. was highly consumed even when it was poorly represented in the field whereas in peri-urban area, A. terrestris,is consumed according to its availability. Taking in account the availability of rodents on the scale of the city, it was shown that the consumption of intermediate hosts is more important in rural area than in urban area and that the rural diet exhibits a predominance of Microtus sp. versus A. terrestris whereas these differences are lacking in urban area. The distribution of faeces of the red fox appeared correlated with the densities of Microtus sp and A. terrestris, underlining the possibilities of closing the parasitic cycle whatever the urbanization level. Lastly, the study of foxes movements using GPS collars has allowed to observe various types of behaviours which could induce a modulation in the space dynamics of the urban transmission of the parasite based on the stability of the local red fox populations.L'Echinococcose Alveolaire est une zoonose mortelle transmise a l'Homme par l'ingestion des oeufs du tænia Echinococcus multilocularis. Le cycle du parasite fait intervenir un carnivore comme hote definitif (principalement le renard roux) et des campagnols prairiaux (Microtus arvalis et Arvicola terrestris) comme hotes intermediaires. Depuis une vingtaine d'annees, les observations de plus en plus frequentes de renards urbains ont suscite de nombreuses questions sur l'augmentation du risque de contamination humaine a cause de cette proximite des renards. Des etudes recentes ont montre la presence d'E. multilocularis chez le renard urbain avec des prevalences tres variables. Cependant, les conditions du developpement de ce parasite dans les milieux urbanises sont peu documentees. Les travaux presentes proposent d'ameliorer la comprehension du cycle d'E. multilocularis dans de tels milieux. Un suivi de l'infection vulpine par collecte de cadavres a mis en evidence un gradient d'infection decroissant du milieu rural au milieu urbain. Le long de ce gradient, differents milieux ont ete regulierement echantillonnes et ont montre l'importance pour le renard roux de la disponibilite en Microtus sp. dans les milieux friches. L'etude de la reponse alimentaire du renard roux aux variations de densites de rongeurs a montre que Microtus sp. etait fortement consomme meme lorsqu'il etait faiblement present sur le terrain alors que A. terrestris, en milieu peri-urbain, est consomme selon sa disponibilite. L'etude de la disponibilite en rongeurs a l'echelle de la ville montre que la consommation en hotes intermediaires est plus importante en milieu rural qu'en milieu urbain et que le regime alimentaire rural se caracterise par une predominance de Microtus sp. par rapport a A. terrestris alors que ces differences sont pas presentes en milieu urbain. La repartition des feces de renard roux est correlee aux densites de Microtus sp et d'A. terrestris, soulignant les possibilites d'existence du cycle parasitaire quel que soit le niveau d'urbanisation. Enfin, l'etude de trajectoires de renards par utilisation de colliers GPS a permis d'observer differents types de comportements individuels qui pourraient entrainer une modulation de la dynamique spatiale de la transmission urbaine du parasite basee sur la stabilite des populations vulpines

Fox defecation behaviour in relation to spatial distribution of voles in an urbanized area: An increasing risk of transmission of Echinococcus multilocularis?

International audienceUrbanization of alveolar echinococcosis is a new phenomenon that has been highlighted during the last few decades. It has thus become necessary to understand the dynamics of transmission of Echinococcus multilocularis in urbanized areas. Spatial heterogeneity of infection by E. multilocularis has been explained as the result of a multifactorial dependence of the transmission in which the factors depend on the scale of the investigation. The aim of this study was to assess, in an urbanized area, the effect of such environmental factors as season, habitat type and the level of urbanization, on the availability of two major intermediate hosts (Microtus spp. and Arvicola terrestris), the distribution of red fox faeces and the distribution of E. multilocularis as determined by detection of coproantigens in faeces. Results of the study revealed higher densities of Microtus spp. in rural than in peri-urban areas. Moreover this species was highly aggregated in urban wasteland. Arvicola terrestris densities did not appear to be linked to the level of urbanization or to the type of habitat studied. Distribution of faeces was positively linked to distance walked and to Microtus spp. and A. terrestris distributions whatever the level of urbanization. Such a distribution pattern could enhance the transmission cycle in urban areas. The Copro-ELISA test results on faeces collected in the field revealed that O.D.s were significantly negatively correlated with the abundance of A. terrestris. The larger population densities of Microtus spp. found in urban wastelands and the well known predominance of Microtus spp. in the red fox diet in the region suggest that Microtus spp. may play a key-role in urban transmission of the parasite in the study area

Multi-annual performance evaluation of laboratories in post-mortem diagnosis of animal rabies: Which techniques lead to the most reliable results in practice?

Rabies diagnosis proficiency tests on animal specimens using four techniques (FAT, RTCIT, conventional RT-PCR and real-time RT-PCR) were organised over 10 years (2009-2019). Seventy-three laboratories, of which 59% were from Europe, took part. As the panels were prepared with experimentally-infected samples, the error rate of laboratories on positive and negative samples was accurately estimated. Based on fitted values produced by mixed modelling including the variable "laboratory" as a random variable to take into account the longitudinal design of our dataset, the technique that provided the most concordant results was conventional RT-PCR (99.3%; 95% CI 99.0-99.6), closely followed by FAT (99.1%; 95% CI 98.7-99.4), real-time RT-PCR (98.7%; 95% CI 98.1-99.3) and then RTCIT (96.8%; 95% CI 95.8-97.7). We also found that conventional RT-PCR provided a better diagnostic sensitivity level (99.3% ±4.4%) than FAT (98.7% ±1.6%), real-time RT-PCR (97.9% ±0.8%) and RTCIT (95.3% ±5.1%). Regarding diagnostic specificity, RTCIT was the most specific technique (96.4% ±3.9%) followed closely by FAT (95.6% ±3.8%), real-time RT-PCR (95.0% ±1.8%) and conventional RT-PCR (92.9% ±0.5%). Due to multiple testing of the samples with different techniques, the overall diagnostic conclusion was also evaluated, and found to reach an inter-laboratory concordance level of 99.3%. The concordance for diagnostic sensitivity was 99.6% ±2.0% and for diagnostic specificity, 98.0% ±8.5%. Molecular biology techniques were, however, found to be less specific than expected. The potential reasons for such findings are discussed herein. The regular organisation of performance tests has contributed to an increase in the performance of participating laboratories over time, demonstrating the benefits of such testing. Maintaining a high-quality rabies diagnosis capability on a global scale is key to achieving the goal of eliminating dog-mediated human rabies deaths. The regular organisation of exercises on each continent using selected local strains to be tested according to the local epidemiological situation is one factor that could help increase reliable diagnosis worldwide. Rabies diagnosis capabilities could indeed be enhanced by providing adequate and sustainable proficiency testing on a large scale and in the long term

Evaluation of the Worldwide Occurrence of Rabies in Dogs and Cats Using a Simple and Homogenous Framework for Quantitative Risk Assessments of Rabies Reintroduction in Disease-Free Areas through Pet Movements

International audienceDog and cat rabies cases imported from rabies enzootic countries represent a major threat for areas that have acquired rabies-free status and quantitative risk analyses (QRAs) are developed in order to assess this risk of rabies reintroduction through dog and cat movements. Herein we describe a framework to evaluate dog and cat rabies incidence levels in exporting countries along with the associated uncertainty for such QRAs. For enzootic dog rabies areas (EDRAs), we extended and adapted a previously published method to specify the relationship between dog rabies vaccination coverage and canine rabies incidence; the relationship between dog and cat rabies incidences; and then to predict annual dog and cat rabies incidences. In non-enzootic dog rabies areas (nEDRAs), we provided annual incidence based on declared dog and cat rabies cases. For EDRAs, we predicted an annual incidence potentially greater than 1.5% in dogs and about ten times lower in cats with a high burden in Africa and Asia but much lower in Latin America. In nEDRAs, the occurrence of rabies was lower and of similar magnitude in dogs and cats. However, wildlife could still potentially infect dogs and cats through spillover events. This framework can directly be incorporated in QRAs of rabies reintroduction

Management practices of dog and cat owners in France (pet traveling, animal contact rates and medical monitoring): Impacts on the introduction and the spread of directly transmitted infectious pet diseases

International audienceA number of owner practices among the pet dog and cat population can influence the dynamics of directly transmitted infectious dog and cat diseases, including zoonotic ones. To better depict these management practices, which include pet traveling, contact rates with other companion animals and their medical monitoring (which herein includes prevention aspects), we surveyed 2,122 dog- and/or cat-owning French households through an anonymous online questionnaire. Trips with dogs within the European Union (EU) were frequent, while cats travelled less frequently within the EU and both cats and dogs travelled less frequently outside the EU. Recurrent illegal trips with dogs and cats (non-compliant with regulatory measures) were observed in a context of non-systematic pet border controls. We found that a large proportion of dogs are taken for walks in metropolitan France, with frequent intraspecific contacts (1.4 contacts/day on average), but only a minority (1.4%) of dogs were allowed to roam freely. On the other hand, 59.7% of cat owners allowed their cats to roam freely. We classified pet owners according to different profiles, some of which may be considered 'at risk' for directly transmitted infectious pet diseases. Indeed, one dog owner profile and one cat owner profile depict 'spreaders' of pet diseases (high connectivity with other individuals, little medical monitoring but no traveling) and another dog owner profile describes a potential 'introducer' and 'spreader' of pet diseases (foreign travel, high connectivity with other individuals, and intermediate medical monitoring). While these 'at risk' profiles represent only a minority of French pet owners, they should be better characterized to reinforce targeted prevention designed to minimize the risk of (re)introduction and (re)emergence of directly transmitted infectious dog and cat diseases in France, especially when considering zoonoses with a significant potential impact, such as rabies