Description of the disease
Rabies is a zoonosis (animal disease that can be transmitted to humans) caused by a virus of the genus Lyssavirus. Found in the saliva of infected animals in the final phases of the disease, the virus is generally transmitted to another animal or to a human through a bite. Contamination may also occur if the saliva of an infected animal comes into contact with a wound or the mucous membranes. Without treatment, the disease is always fatal.
Currently, there are 14 recognised types of rabies. These species of the genus Lyssavirus can generally be differentiated according to their geographical distribution and main animal hosts. So-called "classical" rabies in carnivores is usually caused by the RABV virus, which is the most commonly identified variant in human rabies cases.
Rabies, which causes over 55,000 deaths a year worldwide, is found all over the world except in certain areas with favourable geographical characteristics, such as Australia, Antarctica and the British Isles, and in regions which have eliminated the virus through oral vaccination programmes (Central and Western Europe).
In the industrialised countries, rabies caused by the RABV virus persists only in wild animals (in Europe, mainly foxes and raccoon dogs), whereas it is an endemic disease in many developing countries, where the domestic dog is the principal reservoir and main source of human contamination. In Europe, canine rabies was eradicated several decades ago, but the virus adapted to wildlife at the end of the Second World War. Thanks mainly to oral vaccination campaigns conducted in foxes, vulpine (fox) rabies has been eliminated in France, with the last reported case dating back to 1998. France therefore now fulfils the World Organisation for Animal Health (OIE) conditions for being declared a rabies-free country.
Monitoring of the disease
To avoid any risk of reintroduction, the rabies situation in France is monitored on an ongoing basis. The illegal importation of infected animals from Africa remains a constant concern, and justifiably so since nine cases have been detected in France since 2001.
However, certain types of rabies can affect bats (chiroptera). In Europe, bats are mainly infected with the EBLV-1 and EBLV-2 viruses, which can also infect humans. A new species of rabies virus known as BBLV (currently being ratified by the International Committee for Taxonomy of Viruses [ICTV]), has been reported twice in France in the same species of bat (Natterer's bat). The BBLV virus was first isolated in France in the Moselle region in 2012, and then in Savoy in August 2013. However, the risk of virus transmission from bats to humans in the general public is considered to be negligible due to the low probability of human exposure to bats.
Since 1970, there have been 21 human deaths due to rabies in France, the last one occurring in 2014. All of them were the result of contaminations which took place outside of mainland France.
The work of ANSES
Assessment of risks
With regard to risk assessment, the Expert Committee on animal health and its working groups produced opinions during the last two episodes of canine rabies reintroduction (2004 in the Aquitaine region and 2008 in Seine-et-Marne), and a report was issued in 2003 entirely dedicated to rabies in Chiroptera (bats).
Nancy: a laboratory specialising in rabies
The Nancy Laboratory for Rabies and Wildlife, which specialises in animal rabies, plays a key role in the French rabies monitoring system. For over 40 years, the laboratory has been involved in combating this disease, conducting research and development programmes in particular. It has helped to eliminate the virus in France, and participates actively in European and international eradication plans. As a National Reference Laboratory, it diagnoses rabies in animals which have not contaminated humans. In 2013, 422 samples were received for rabies diagnosis. The laboratory also heads up a national network for monitoring lyssavirus infections in bats. In this framework, 300 bats were received and analysed by the laboratory in 2013.
In addition to its national activities, the laboratory also plays a key role at the European level with two European Union Reference Laboratory (EURL) mandates, for rabies and rabies serology. It is in charge of evaluating laboratory performance both for classic diagnoses and for post-vaccination serological testing. For the latter, the laboratory issues certificates attesting to the technical proficiency of 65 international laboratories involved in controlling the efficacy of vaccinations for dogs and cats travelling to rabies-free countries.
Internationally, the Nancy Laboratory for Rabies and Wildlife is an OIE reference laboratory for rabies, and its role is to provide expertise and laboratory services which contribute to reinforcing the capacities of National veterinary services and the safety of trade, as well as diagnostic assistance for the detection and prevention of rabies.
It is also a World Health Organisation (WHO) collaborating centre for the management of zoonoses. As such, it participates in the development and application of rabies guidelines and provides scientific opinions on the methods for controlling animal rabies.
The laboratory performs research activities aiming to evaluate the pathogenicity of bat viruses circulating in France in domestic carnivores (cats and dogs) and wild carnivores (foxes and raccoon dogs) as well as on the ability of the lyssavirus to cross species barriers.
Information for professionals
While no cases of fox rabies have been reported in France since 1998, rabies remains a threat in the country. Indeed, canine rabies cases do occur sporadically due to the unlawful introduction into France of dogs incubating the disease. This phenomenon is not new, but appears to be growing despite new European measures to control animals at the border. Vigilance is therefore required for this disease which can be transmitted from animals to humans, especially among the veterinarians, physicians, and diagnostic laboratories that are essential links in this monitoring system.