Rabies is an infectious disease that affects the central nervous system of both domestic and wild mammals as well as humans (zoonoses) so severely that it leads to death. The infection is transmitted with the bite, with the licking of the mucous membranes or of the solutions continuously from infected animals.
They can be dogs, cats, wolves, foxes, rodents, etc. Wild animals are the natural reservoir of rabies (sylvan rabies) and the dog can act as a unifier between sylvan and urban rabies. According to some authors, the virus at the point of penetration, in the muscle fibers and in the connective tissue, remains for some time and multiplies to then reach, through the nerve axons, the central nervous system. According to other authors in the bite site there is no viral replication, but immediately migration of the virus towards the central nervous system, upon reaching which the virus invades it, multiplies and distributes itself along the nerves, this time in a centripetal manner. In this period the virus is eliminated through the salivary glands which constitute a point of understanding viral multiplication. The 700% of affected dogs have high virus titers in their salivary glands. The possibility of an infected animal spreading rabies through saliva to other animals is high as it is infectious up to five days before the onset of bedbug symptoms. Incubation can range from a minimum of five days to a maximum of 10-14 months but is usually between two and eight weeks.
• Symptoms - Initially there are character variations. The unapproachable and aggressive dog becomes docile, while the affectionate and sociable one becomes aggressive. There is a tendency for individuals to hide in dark, secluded places in an anorexic state with subfebrile temperature. Hallucinative phenomena become evident later. The dog growls, barks, celebrates imaginary things and people, performs the act of catching flies with its mouth.
In this first phase, a modest squint, oscillatory and sometimes rotatory movements of the eyeballs can be observed. Intense itching may appear on the skin, at the site of the wound or bite. This symptom, not always present, can be so accentuated as to lead the dog to get serious injuries. The dog has an excessive need to eat anything due to the lack of the sense of satiety and taste, going so far as to swallow any object (stones, nails, glass, wood, paper, etc.). Then there is intense thirst but due to the paralysis of the larynx the animal is unable to swallow. There is abundant production of saliva and loss of saliva. Also due to pharyngolaryngeal paralysis, the voice undergoes changes and the barking becomes hoarse barking and protracted howl. In 25% of cases of rabid dogs, states of considerable excitement occur which can be short-lived but can last up to 5 hours and recur after moments of tranquility. In this phase the dog has a shaggy appearance, bites whatever comes in front of it and runs, if not stopped, long distances (40-50 km). Then follows a generalized paresis which is evidenced by weakness of the legs and tail, ptosis of the eyelids, sometimes of the tongue as well as of the jaw and persistent difficulty in swallowing. The eyes show dilation of the pupils, strabismus, procidence of the third eyelid. As a final fact, breathing becomes difficult and paresis of the respiratory muscles intervenes. The course of the disease is hardly more than two weeks, usually death occurs five days after the onset of nervous symptoms.
• Laboratory tests - Clinical diagnosis is not easy in the living subject, therefore laboratory tests are necessary. The histological examination done on the brain material is not always reliable. Immunofluorescence is the laboratory method that reveals the presence of the virus from the first moment it invades the central nervous system, so it is considered an excellent laboratory investigation.
• Differential diagnosis - The state of excitement can escape the owner, given the short duration of its duration, so the possibility of a dog suffering from rabies when it has changes in character accompanied by progressive paralysis must always be considered. It is therefore necessary to take into consideration those diseases that can involve the central nervous system such as distemper, pseudorabies, toxoplasmosis, epheme, brain tumors, traumatic events, poisonings, foreign bodies in the oropharyngeal cavity, calcium-deprived tetanias, uremia.
• Prophylaxis - It is aimed at preventing infection in humans. The dog suspected of rabies is not killed but isolated in a safe box for at least ten days and checked both from a symptomatic point of view and with laboratory tests. The dog with rabies rarely lives beyond five days after the onset of nervous symptoms. The vaccines currently available are sufficient to stimulate the body, to produce antibodies against rabid infection. The vaccine commonly used today consists of live virus, attenuated Flury strain.