Smallpox is a rare, contagious life-threatening infection caused by exposure to a virus called variola. There are two distinct forms of smallpox infection: variola major, which causes severe life-threatening side effects; and variola minor, which causes milder side effects. Smallpox was eradicated as an active infectious disease worldwide by 1980, according to the MayoClinic.com. Still, there is no cure for the disease once it reaches a human host. Samples exist in laboratories for research purposes, and anyone who develops smallpox symptoms needs to seek medical help immediately to prevent spreading this infection to other uninfected people.
High Fever
One of the first side effects of smallpox is a high fever that ranges between 101 and 104 degrees F, warn medical experts with the Centers for Disease Control and Prevention. A high fever can contribute to additional side effects in infected people, such as headaches, sweating or chills. A fever that occurs due to smallpox typically arises within one to two weeks following exposure to the variola virus and can persist for several days.
Fatigue, Malaise and Backache
People exposed to the smallpox virus can develop side effects of fatigue, malaise and backache, report health professionals with the National Institute of Allergy and Infectious Disease. These side effects are typically severe and can prevent an infected person from moving about normally or participating in daily activities. Affected people may sleep for long periods of time throughout the day or complain of body discomfort. These side effects of smallpox typically persist for at least two to four days.
Upset Stomach
Upset stomach side effects can arise in people who have smallpox. These side effects can include nausea, vomiting or diarrhea, explain medical professionals with MayoClinic.com. Diarrhea can contribute to additional side effects, such as abdominal cramping or bloating. People who develop upset stomach side effects due to smallpox can also experience a temporary loss of appetite.
Skin Rash
The characteristic side effect of smallpox is a skin rash that appears after a fever and other flu-like symptoms arise. Initially, small red skin lesions can appear within the mouth and along the tongue of infected patients, according to CDC health experts. These skin lesions become worse over several hours and eventually burst open, allowing the virus to spread into the throat and throughout the body. During this stage of smallpox infection, affected people are highly contagious. Within 24 hours of the emergence of the initial skin rash, people with smallpox can develop skin lesions across their entire body, including the face, arms, legs and feet. Over the next two weeks, these skin lesions progress into small, raised bumps, which eventually form hard pustules that burst and develop a crusty scab. These skin pustules are very painful and can be fatal in certain people. During the third week following the onset of skin rash symptoms, the scabs begin to flake off, leaving behind red, pitted scars. Once all of scabs have fallen off, the infected person is no longer contagious.
