Rabies Health Article

Definition

Rabies is an acute viral disease of the central nervous system that is transmitted through saliva from the bite of an infected animal.

Description

Rabies affects humans and other mammals but is most common in carnivores (flesh eaters). It is sometimes referred to as a zoonosis, or disease of animals that can be communicated to humans. Rabies is almost exclusively transmitted through saliva from the bite of an infected animal. Another name for the disease is hydrophobia, which literally means fear of water, a symptom shared by half of all people infected with rabies. Other symptoms include fever, depression, confusion, painful muscle spasms, sensitivity to touch, loud noise, and light, extreme thirst, painful swallowing, excessive salivation, and loss of muscle tone. If rabies is not prevented by immunization, it is almost always fatal.

In late 2002, rabies re-emerged as an important public health issue. Charles E. Rupprecht, director of the World Health Organization (WHO) Collaborating Center for Rabies Reference and Research, listed several factors responsible for the increase in the number of rabies cases worldwide:

• Rapid evolution of the rabies virus. Bats in the United States have developed a particularly infectious form of the virus.
• Increased diversity of animal hosts for the disease.
• Changes in the environment that are bringing people and domestic pets into closer contact with infected wildlife.
• Increased movement of people and animals across international borders. In one case, a man who had contracted rabies in the Philippines was not diagnosed until he began to feel ill in the United Kingdom.
• Lack of advocacy about rabies.

Demographics

Cases of rabies in humans are very infrequent in the United States, averaging one or two a year (down from over 100 cases annually in 1900), but the worldwide incidence is estimated to be between 30,000 and 50,000 cases each year. These figures are based on data collected by the World Health Organization (WHO) in 1997 and updated in 2002. Rabies is most common in developing countries in Africa, Latin America, and Asia, particularly India. Dog bites are the major origin of infection for humans in developing countries, but other important host animals are the wolf, mongoose, and bat. Worldwide, the highest risk groups for contracting rabies are boys under the age of fifteen. Most deaths from rabies in the United States result from bat bites.

People whose work frequently brings them in contact with animals are also considered to be at higher risk than the general population. This group includes those in the fields of veterinary medicine, animal control, wildlife work, and laboratory work involving live rabies virus. People in these occupations and residents of or travelers to areas where rabies is a widespread problem should consider being immunized.