To understand how rabies is transmitted or spread from animals to humans and animals to animals, it is important to know what rabies is and how it causes the disease.
Rabies is a deadly disease that is caused by viruses most commonly through bites from the saliva of infected animal hosts. Viruses are small microorganisms that are smaller than bacteria. They grow and multiply inside a living cell. Once the virus enters the body, they travel to the brain, infect it, resulting to a gamut of symptoms that will inevitably lead to death within days once the disease manifests.
The early manifestations of the disease among humans are hard to distinguish with other illnesses. They include fever, general weakness or discomfort, headache, nervousness, sore throat, and pain or tingling sensation at the site of the bite. Later, as the disease develops, the following symptoms appear: agitation, anxiety, confusion, difficulty in swallowing, excitation, fear of water (hydrophobia), hallucination (seeing things that are not there), increased salivation, insomnia, and partial paralysis. Ultimately, the person will go into coma and eventually, death.
Only mammals (animals that have hair and nourish their babies through milk from the mammary glands) can have rabies. These animals include bats, cats, dogs, elephants, foxes, raccoons, skunks, and the like. Animals such as birds, chickens, fish, frogs, and snakes do not get rabies.
Animal-to-human spread of the rabies virus starts from an animal—say for example, a dog—harboring the deadly microorganism. Once the infected dog bites a human being, viral spread happens. Bites are the most common mode of transfer of the virus. The virus can also spread once the infected dog licks open wounds. It can also happen through scratches because the paws may contain the infected saliva of the animal. So, be very careful about it. Open wounds or cracks in the skin are points of entry of the virus once the infected animal gets in contact with them.
However, it is important to remember that not all bites, licks, and scratches will result to rabies. In fact, the majority do not cause rabies particularly when the animal received vaccination.
A rare mode of transmission of the virus from animals to man is through eating raw meat of animals like dogs, as practiced in some cultures. There had been documented cases of rabies developed by aerosol inhalation of massive amounts of the virus, and by transplantation of cornea (a part of the eye) and other body organs.