Rabies: a disease present on all continents
Rabies is a zoonosis, ie an animal disease transmissible to humans (and vice versa), caused by a virus of the genus Lyssavirus.
How is the disease transmitted?
Present in the saliva of infected animals before the appearance of the first clinical signs, the virus is mainly transmitted to another animal or to humans by bite. The saliva of a rabid animal in contact with a wound or mucous membrane can also cause contamination. As soon as the clinical signs appear, the disease always has a fatal course.
There currently exists 17 virus species recognized rabies. These species of the genus Lyssavirus are globally differentiated by their geographical distribution and by the main hosts that harbor them. The so-called “classic” rabies of carnivores is most often linked to virus RABVthe most frequently identified in human rabies cases.
Where is the disease present?
Provoking more than 55,000 deaths per year in the world, terrestrial rabies is present all over the globe with the exception of certain territories, either because of a particularly favorable geographical situation, such as Australia, Antarctica or the British Isles, or having eliminated the virus through oral vaccination programs in central and western European countries.
In industrialized countries, rabies due to the RABV virus persists only in wildlife. In Europe, dog rabies was eradicated several decades ago, and the virus adapted to wildlife at the end of the Second World War, mainly in foxes and raccoon dogs.
France fulfills the conditions of a rabies-free country according to the definition of the World Organization for Animal Health (OMSA). Thanks in particular to oral anti-rabies vaccination campaigns conducted among foxes, vulpine rabies, affecting foxes, has been eliminated from French territory, the last case recorded dating back to 1998. Since 1970, 23 human deaths due to rabies occurred in France, the last dating back to 2019. Almost all followed contamination outside mainland France by a “classic” strain of rabies virus.
On the other hand, in many developing countries, rabies is an endemic pathology. In these countries, dogs are the main reservoir and the main source of human contamination.
A disease under surveillance
To avoid any risk of reintroductionthe animal rabies situation in France is constantly monitored. The illegal importation from Africa of infected carnivores In particular, there remains a constant concern justified by the consequences of the 11 cases detected in France since 2001, the last case dating back to February 2020 in a dog contaminated with a strain from Morocco.
Forms of rage touching bats, or bats, do exist, however. In Europe, they are mainly due to the EBLV-1 and EBLV-2 viruses, which can infect humans. In 2012 (Moselle) and 2013 (Savoie), a new species of virus, the BBLV virus, was reported on the same species of bat (Vespertilion de Natterer). In 2017 (Jura), another new lyssavirus (LLEBV) was identified on a new bat species, Schreibers’ Minioptera.
For the general population, however, the risk of virus transmission from bats to humans is considered very low due to its low probability of exposure to bats.
A laboratory specializing in rabies in France, Europe and around the world
Animal Rabies Specialist, Nancy Rabies and Wildlife Laboratory plays a major role in the French rabies surveillance system. For nearly 50 years, the laboratory has been involved in the fight against this disease, in particular by conducting research and development and expert appraisal programs. It has contributed to its elimination from the national territory, and actively participates in European and international eradication plans.
National reference laboratory, it carries out rabies diagnosis in animals not having contaminated the human being. Some 495 samples are received annually for rabies diagnosis. The laboratory is also at the head of the national network for surveillance and monitoring of lyssavirus infections in bats. In this context, 400 bats on average are sent to the laboratory every year.
In addition to its national activities, the laboratory also plays a major role at European level with two European reference laboratory mandates for rabies and rabies serology. It is responsible for evaluating the performance of the laboratories both for the diagnosis of rabies and for the post-vaccination serological control. In the latter case, the laboratory issues certificates attesting to the technical performance of the 80 international laboratories involved in checking the effectiveness of the vaccination of dogs and cats traveling from rabies-endemic countries to Europe.
At the international level, the rabies and wildlife laboratory in Nancy is OMSA reference laboratory for rabiesand it provides expertise and laboratory services contributing to strengthening the capacities of national Veterinary Services and the safety of trade as well as diagnostic assistance for the detection and control of rabies.
he is also World Health Organization Collaborating Center (WHO) for the management of zoonoses. It thus participates in the development and application of guidelines relating to rabies and provides scientific expertise on animal rabies control methods.
Finally, the laboratory conducts research activities intended to assess the pathogenicity of bat viruses circulating in France on domestic carnivores and foxes, as well as the crossing of species barriers by lyssaviruses. Research activities are also carried out through international collaborations, most of which are intended for epidemiological and phylogenetic studies as well as the development of new detection tools.
Rabies Risk Assessment
In terms of risk assessment, the expert committee specialized in “Animal Health” and its working groups produced opinions during episodes of reintroduction of canine rabies (from 2004 in the Aquitaine region and from 2008 in Seine- et-Marne). Two opinions were also published in 2007 and 2008 on the risks of contamination in French Guiana where a new case was diagnosed in August 2015 in a dog. A report published in 2003 is entirely devoted to bat rabies. Finally, a last opinion published in April 2020 deals with the question of interpretation of rabies tests in puppies (PDF) traveling within the European Union.
Information for professionals on rabies
Although no case of fox rabies has been observed in France since 1998, rabies remains a threat to our territory. In effect, cases of canine rabies appear sporadically following the illegal introduction of dogs incubating rabies in our country. This phenomenon is not new, but seems to be progressing, despite European regulations for controlling pets at borders.
Vigilance and awareness of this animal disease transmissible to humans therefore remains essential, in particular among veterinarians, doctors and laboratories in charge of diagnosis who are all essential links in this vigilance.