Untreated, rabies causes a painful death. .
Most animals can be infected by the virus and can transmit the disease to man. Infected bats, raccoons, foxes, skunks, dogs or cats provide the greatest risk to humans. Rabies may also spread through exposure to infected domestic farm animals, groundhogs , weasels and other wild carnivores. Squirrels, rodents and rabbits are seldom infected.
Following primary infection the virus enters an eclipse phase in which it cannot be easily detected within the host. This phase may last for several days or months. Investigations have shown both direct entry of virus into peripheral nerves at the site of infection and indirect entry after viral replication in nonnervous tissue. During the eclipse phase, the host immune defenses may confer cell-mediated immunity against viral infection because rabies virus is a good antigen . The uptake of virus into peripheral nerves is important for progressive infection to occur . .
Smallpox.
Smallpox is a serious, contagious, and sometimes fatal infectious disease. There is no specific treatment for smallpox disease, and the only prevention is vaccination. The name smallpox is derived from the Latin word for "spotted" and refers to the raised bumps that appear on the face and body of an infected person.
There are two clinical forms of smallpox. Variola major is the severe and most common form of smallpox, with a more extensive rash and higher fever. There are four types of variola major smallpox: ordinary (the most frequent type, accounting for 90% or more of cases); modified (mild and occurring in previously vaccinated persons); flat; and hemorrhagic (both rare and very severe). Historically, variola major has an overall fatality rate of about 30%; however, flat and hemorrhagic smallpox usually are fatal. Variola minor is a less common presentation of smallpox, and a much less severe disease, with death rates historically of 1% or less.
