Systematic Veterinary Virology

TRANSMISSION

• Rabies virus is more commonly transmitted to a new host only through an open wound or, less likely, through the mouth, the eyes, or the mucous membranes of the nose. Since the virus is present in the saliva and brain material of infected individuals, most transmission events occur through bite wounds.
• The respiratory transmission has been reported in very rare circumstances. The incubation period vary from as little as a few days to many years in rare cases. However, in most cases, incubation occurs within one to three months. Once an individual is infected with the rabies virus, it replicates within the cytoplasm of muscle cells and pass from cell to cell.
• Finally, it reaches nerve receptors and enters the nervous system. The virus passes along the nerve network, traveling to the central nervous system, where it concentrates in the brain and upper spinal cord. As the disease progresses, the virus continues to multiply and spreads back through the peripheral nervous system to the salivary glands.
• Not all animals or humans exposed to the virus contract the disease. However, once symptoms become evident, the disease usually is fatal. Many animals like dogs, bats, skunks act as reservoirs.
• When dogs act as reservoirs for spread of rabies to other animals including dogs it is referred as canine rabies. In Asia, Africa and Europe canine rabies are common. However, in US bat rabies pose major problem.