Rabies

Synonym: Sometimes called hydrophobia

What is it?

Rabies is a lethal viral disease affecting a wide range of domestic and wild mammals, including humans. It is both the most feared and best known zoonotic disease and is thought to have the highest case fatality rate of any disease. In developing countries, rabies is mostly transmitted by dog bites, although in rural areas wild animals may sometimes be responsible. Children are at higher risk because of their size and behavior. Dogs are less afraid of children than of adults and children express less caution towards unknown or sick dogs, so that children are more easily bitten. Because of their smaller size, children tend to get bitten nearer the brain, so that the virus has a shorter distance to travel to the brain, so that once bitten, the disease develops faster.

Simplified text: Rabies Disease card (English only); Rabies, CDC (English only); Rabies, FAO (English only)
Simplified video: Global alliance for Rabies Control (3'44; English only)
Technical text: Rabies portal, OIE (English, French and Spanish); Rabies, WHO (English only)

How to recognize it

Rabid animals present signs of abnormal brain function (encephalopathy) with associated behavior changes. The first symptoms appear weeks or even months after exposure to a rabid animal. Animals become progressively paralysed and eventually fail to walk or even stand. Animals are unable to swallow following the paralysis of the larynx, causing apparent salivation. Fear of water is caused by the fact that the animal is thirsty but unable to drink, and for this reason the disease is sometimes called hydrophobia. Paralysis of the larynx also causes severe changes to the voice. Animals appear either angry and aggressive (furious form) or apathetic and attracting sympathy (paralytic form). Wild animals lose their fear of humans and other animals. Clinical rabies is always lethal.

Simplified text: Rabies, CDC (English only)
Technical text: Rabies OIE manual (English only)
Technical video: Brain histopathology (2'57; English); Rabies in Asia Foundation (45'17; English)

In humans, both furious and paralytic forms are observed. Incubation may be very long, especially if the bite is far from the brain (e.g. foot). In humans, the initial symptoms are fever and often pain or tingling or burning sensation at the wound site. People with furious rabies exhibit excited behaviour and a fear of water. Paralytic rabies is less dramatic and usually follows a longer course than the furious form. The muscles gradually become paralyzed, starting at the site of the bite or scratch. A coma slowly develops, and eventually death occurs. The paralytic form of rabies is often misdiagnosed, contributing to the under-reporting of the disease.

Diagnosis is confirmed using brain biopsies.

Simplified text: Rabies, CDC (English only)
Technical text: Rabies OIE manual (English only)
Technical video: Brain histopathology (2'57; English); Rabies in Asia Foundation (45'17; English)

How to control it

Vaccination and quarantine of dogs imported from endemic countries. Importation of dogs from endemic areas should not be allowed unless they are vaccinated. Unvaccinated animals should be quarantined for 4 months.

Surveillance of wild and domestic animals with neurological disorders. Wild and domestic animals exhibiting strange behavior (absence of fear, aggressiveness, paralysis or a strange voice) should be reported and monitored. Suspected rabid animals should ideally be captured for monitoring and diagnosis. If not possible, they should at least be slaughtered to avoid propagation of the virus. Extra precautions must be taken when handling live or dead animals that may have rabies.

Surveillance of human cases. Humans only contract rabies from rabid animals. If it is suspected that humans have rabies, epidemiological investigation must be undertaken to identify and neutralize the animal source of infection. Rabid persons are not contagious (they cannot transmit the disease to other humans or animals), so that particular measures to protect relatives and health workers from infection are not required.

General considerations on dog management

In Africa, most stray dogs are associated with a human community that provides them with food. Some apparently stray dogs are actually owned, but left to roam freely. Some stray dogs return to the wild (feral dogs) but struggle to reproduce. As a consequence, most feral dogs come from owned or stray dog populations. Controlling births among owned and stray dog populations would, therefore, have an impact on all dog populations, including feral dogs.

Unfortunately, no easy and cheap contraceptive methods are available. Castration of males is not useful because one single male can fertilize many females. Spaying female dogs is recommended but more difficult to implement. Alternatively, euthanasia of pups could be recommended but this should be done in a humane way, probably requiring veterinary expertise.

Killing dogs has been demonstrated in to be counterproductive in several situations because the killed stray and feral dogs are quickly replaced by new dogs from outside the community, with the attendant risk of bringing in diseases (e.g. rabies). The dog capture, sterilization, vaccination, treatment and release method is recommended but, again, is very demanding for veterinary services.

Finally, stray dogs mostly feed on waste. Improved waste management is likely to result in reduced stray dog populations.

Simplified text: Guidelines from World Society for the Protection of Animals (English only)
Simplified video: Estudio demografico sobre la tenencia responsable de mascotas y prevencion de la hidatidosis (Chilean video) (4'41; Spanish); FAO film on rabies control (21'00; English only); Rabies control in Liberia (4'18; English only)
Technical text: OIE terrestrial manual code (English only); WHO guidelines for dog management (1990; English only); WHO report on echinococcosis control (English only)

Avoid contacts with rabid animals. Animals exhibiting rabies often attract curiosity from humans and other animals. Rabid animals bite them while they examine them. People should be able to identify rabid animals to reduce the risk of exposure. Live wild animals should never be touched, unless they were shot or trapped. Game animals exhibiting strange behavior should be handled with care and should not be used for food. Domestic animals exhibiting madness should be captured or killed, while avoiding being bitten. Paralyzed animals should not be approached unless the cause of paralysis is evidently not rabies.

Vaccination of dogs. In Africa, the dog is the main source of rabies. Whereas some wild animals can also be infected, dogs maintain the transmission to humans and other domestic animals. As a consequence, vaccination of dogs prevents the dissemination of rabies to humans and domestic animals. The vaccine is protective for 3 to 5 years. However, in endemic areas, annual vaccination is usually recommended. This compensates for the lack of coverage and vaccination failure and for the fact that dog demographics are such that many dogs only live for 2 years so that the population is rapidly renewed. In endemic areas of Africa, dog vaccination should be compulsory and free of charge. Unfortunately, vaccination requires the dog to be caught and handled. When the number of outbreaks reach a critical number, experienced teams could be trained and hired to catch and vaccinate all dogs (using nets) in cities, towns and villages.

Vaccination of human beings. The risk of human rabies at individual level is too low to justify mass vaccination. However, persons at high risk could be preventively vaccinated (for instance, veterinarians and people capturing and monitoring rabid animals).

Post-exposure treatment in humans. In case of any animal bite, the wound should be thoroughly cleaned and disinfected, whether the animal exhibited signs of rabies or not. Early local disinfection will reduce the risk of clinical rabies. There is no treatment against rabies but the course of the disease is so slow that post-exposure vaccination is possible. Bitten people should therefore report to a physician as soon as possible after the bite. Post-exposure vaccination is cumbersome, painful and expensive. Ideally, the biting animal should be captured and quarantined for 10 days to confirm whether it is rabid or not. The outcome of the quarantine may affect the course of the treatment and what epidemiological investigations need to be implemented to identify other exposed individuals.

Education. Education of people in general, and children in particular, is of paramount importance to avoid bites by rabid animals. People, including children, should be able to identify potentially rabid animals presenting signs of madness. They should also be aware of post-exposure procedures after a bite by a suspected rabid animal: local treatment of the wound, report to the clinic for post-exposure treatment and isolation of the live rabid animal for veterinary monitoring.

Popularized illustrations: Global alliance for Rabies Control (English, French, Spanish, Portuguese and others)
Simplified text: Canine Rabies Blueprint (English, French, Spanish, Portuguese and others); FAO news (English, French, Spanish, Portuguese and others)
Simplified video: Global alliance for Rabies Control (3'44; English only); Global alliance for Rabies Control in Tanzania (3'13; English); Mission rabies in India (4'44; English); Rabies in South-Africa (14'50; mix of English and other South-African languages with English subtitles); Rabies in the Philippines (3'29; English)
Technical text: FAO develops Rabies education package (English only); OIE Terrestrial code (English only); Rabies OIE manual (English only)
Technical video: OIE Interview of Dr Tordo (4'53; English); Rabies in Asia Foundation (45'17; English)

Cultural and geographical specificities

Adapted messages should be developed to best suit the different socio-cultural targets. In some places, extension work failed because of a misunderstanding between the veterinary services and the communities: people understood that vaccination would make their dog less aggressive (and thus more effective as guard dogs). To avoid misunderstanding the concept of madness might better describe the behavioral changes caused by rabies than aggressiveness.

Pastoralist communities

Pastoralists usually have poor access to emergency medical and veterinary services, especially emergency medical services. Cell phones could be used to report potential exposures to rabies and seek medical advice.

In pastoral areas, dog vaccination against rabies could advantageously be combined with annual livestock vaccination campaigns and human health campaigns. There have also been successful examples of combining animal vaccination campaigns with human vaccination campaigns, such as for measles.

Cattle owners must be made aware of the risk of rabies in cattle. Rabid cattle salivate and make strange noises. Checking inside the cattle’s mouth or throat with a hand involves a serious risk of exposure to rabies.

Biting dogs should be quarantined for 10 days and reported to veterinary services unless the risk of bite is too high, in which case they should be slaughtered to avoid other bites. Quarantine of dogs might not be easy to implement in pastoral settings. Vital needs should be provided to quarantined animals (water, food and shade).

Simplified video: Global alliance for Rabies Control in Tanzania (3'13; English)

Communities in northern Africa and the Sahel region

Above all, people should be strongly encouraged to bring their dogs for vaccination. Such occasions can also be used to treat dogs for other health problems and make their owners aware of other dog-related health issues and risks, such as hydatid disease (cystic echinococcosis) and visceral leishmaniasis.

Paradoxically, in areas where post-exposure vaccination of human patients is practiced efficiently, people have little or no experience of human rabies. As a result they tend be less likely to take part in dog vaccination campaigns.

Biting dogs should be quarantined for 10 days and reported to veterinary services unless the risk of bite is too high, in which case they should be slaughtered to avoid other bites. Quarantined animals should be provided with basic needs water, food, shelter and shade).

In Arabic and Berber communities, public awareness could build on the Muslim hadiths in relation to dogs, which recommend low dog populations and reduced contacts with dogs. Unfortunately these hadiths also tend to make dogs living close to human communities less easy to handle for veterinary interventions (treatment, sterilization or euthanasia) because they are not used to being manipulated.

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Mixed farming communities in more humid regions

In such communities, dogs are mostly kept for protection. Participating in annual vaccination campaigns poses two problems. First, people wrongly believe that vaccination affects the temper of dogs. Second, dogs leaving the household to go for vaccination are not on duty. Veterinary services might need to consider this latter constraint by, for instance, distributing the vaccine at village level. Herd dogs could be vaccinated during livestock vaccination campaigns.

New extension messages need to aim at eradicating the belief that rabies could be of any use (perhaps just because rabid dog will punish the thief). Rabies is always fatal to the dog that is infected and detrimental to the animals and people in its direct environment.