Page 552 - The Veterinary Laboratory and Field Manual 3rd Edition

Important zoonotic diseases 489

saliva following a bite from a rabid animal. In the If rabies is suspected it is important to con-
sylvatic cycles the main reservoir hosts include tact the relevant authorities and to wear
small carnivores, such as stoats, weasels, civets appropriate PPE. If bitten the wound should
and the mongoose, as well as larger carnivores, be thoroughly washed with soap and water
such as the wolf, wild dog, foxes and jackal. Bats and a series of post exposure prophylaxis
may also act as reservoir hosts and cause a pro- treatments given. https://www.who.int/
portion of the rabies cases in humans, infection rabies/resources/en/
can occur via a bite or by inhaling infectious
material. In urban areas, the most important
reservoir host is the domestic dog. Ruminants, ringworm
horses and humans may become infected if
bitten by a rabid wild, or domestic, animal. Cause: Microsporum canis, Trichophyton spp. and
others
Signs in animals: The virus acts on the nervous
system and results in unusual behaviour. There Epidemiology: These fungi live in the keratin
may be a furious form and a dumb form in the layers of the skin and in the hair coat of various
same animal but often one phase will predomi- domestic and wild animals. Animal to animal
nate. In domestic dogs the animal may become and animal to human transmission occurs via
aggressive, saliva may form around the mouth direct contact with infected skin and hair or by
and the animal may be unable to eat or drink. contact with contaminated bedding and groom-
Rabid cattle may become more friendly or more ing equipment. Signs in animals: There may be
aggressive than normal and often bellow. few signs or there may be hair loss with scaling
of the skin and the formation of plaques. The
Diagnosis: Quarantine any animal suspected to hair may be brittle and discoloured. The skin
have rabies. An infected dog usually dies within lesions are rarely itchy unless there is some sec-
10 days following the onset of signs. Send the ondary bacterial infection. Animals with severe
entire head (chilled) to the laboratory after noti- ringworm often have an underlying immune
fying the nearest veterinary unit. deficiency and therefore other diseases should

Note: diagnosis is possible on a brain speci- also be considered.
men even after a degree of necrosis. Examine Diagnosis: Hair and skin scrapings from infected
for rabies by FAT, ELISA . There are also kits animals. Other samples as indicated for a gen-
1
available from WHO with swabs to take a brain eral health profile. Microscopy and culture.
smear sample without fully opening the skull
and a preservative to place the swab in to send Control. A number of anti-fungal washes and
to the laboratory. Molecular tools are also now creams are available. Dermatophilus sp. (bacterial
available to confirm a diagnosis. skin infection) may cause similar skin lesions
in livestock so this should also be considered.
Control: Vaccinations are available for people Antibiotics for secondary skin infections may
considered ‘at risk’, for example, animal han- be required. Humans should make sure that
dlers, and for domestic dogs, cats and livestock. they wash their hands after handling infected
In some countries vaccination campaigns are animals. Wash contaminated equipment and
also used to control the virus in wild animal bedding and so on using antifungal chemicals.
populations (for example, foxes). In urban areas
there should be a programme for controlling the
number of stray dogs, for example, neutering.

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