History: A six-year-old boy girl develops high fever to 104, headache, malaise and severe back pain. The patient was described as severely ill. On the fourth day, a rash developed, starting on face and peri-oral region and spreading centrifugally to arms and legs and finally to the palms and soles. The patient’s trunk is also affected but to a lesser extent. The patient’s sister was noted to have a similar presentation and is also severely ill. The rash was initially a flat, macular eruption, then became raised. He is now noted to have dry cough, and poor oral intake.
On physical examination, the boy looks critically ill. He is aware and alert, but tachypneic and blood pressure is 80/50. Rash is widespread, deep-seated, firm, and has a central umbilication and appears pustular. The eyes are beginning to be irritated, and redness is noted of the conjunctivae bilaterally. There is no eschar to suggest anthrax and lesions all appear in the same stage of development, unlikely chickenpox, which are typically in different stages of development at the same time.
There are no lab data available.
Diagnosis: Smallpox
Smallpox is caused by the Variola Virus, an Orthopox virus in the Poxviridae family. Incubation period is typically around 7-17 days. During this period, the patient is asymptomatic and is not contagious. Symptoms are systemic with high fever, severe back pain, severe malaise, and headache and the patient appears severely ill. Rash follows, going through macular, popular, vesicular, and pustular phases. The rash starts on the face and mouth and spreads centrifugally to the extremities, which is the opposite of most viral exanthems. As Thomas Sydenham, prominent 17th century physician, observes “The pustules spread thickest on the face and extremities, so that one might see no part free from them. Fever and dreadful pains torment the patient before eruption; after which, although fever sometimes abates, the danger does not. Ocular involvement is a common source of corneal scarring and blindness to those who survive.
Mortality rate is upwards of 30% for Variola Major, and @ 1% for the milder form, Variola Minor. The Variola Virus causes an initial viremia and liver, lung, splenic, and bone marrow tissue are initially affected. A severe secondary viremia then occurs, with a massive cytokine response creating a cytokine storm that can lead to shock, vascular collapse, mutli-system organ failure, and death. A hepatitis-like dysfunction occurs in the liver, and, if severe enough, can lead to DIC and what’s termed “hemorrhagic smallpox.” Lung involvement causes a viral pneumonitis, and bone marrow involvement cause cytopenia’s to various degree’s, including neutropenia, which can lead to secondary staph aureus bacteremia and sepsis due to breakdown in the integumentary system. The complications resulting from this secondary viremia is what makes Smallpox so lethal.
Transmission is by droplet, usually to the nose or mouth to the unwary recipient. By day ten, rash begins to scab. Until all lesions are scabbed, the patient remains contagious.
Recurrent outbreaks in the 20th century alone are said to have resulted in 300-500 million deaths. Smallpox has been a threat to mankind for centuries. There is no animal reservoir. It was introduced by European colonizers and devastated aboriginal inhabits of the America’s, who had no natural immunity to the virus. The disease has caused widespread panic and fear over the centuries and devastated entire communities and populations. Smallpox was eradicated by vaccine. The last known case was in Somalia in 1977. Jenner noticed that milkmaids who had previously caught Cowpox, a similar but much milder disease in humans, seemed immune to Smallpox. The Cowpox virus, later termed Vaccinia Virus, is part of the Poxviridae Virus family. In 1796, Jenner took pus from Cowpox blisters on a milkmaid named Sarah Nelmes and inoculated it into an 8-year-old boy named James Phipps. The boy developed a mild illness, then recovered. Jenner then vaccinated himself and then deliberately exposed himself to Smallpox, but did not develop the disease, proving he was immune. The term vaccine comes from Vacca, the Latin word for cow, as Jenner termed his method Variolae Vaccinae, or smallpox of the cow. Jenner’s work laid the foundation for modern immunology and led to the disease being extinguished from the world.
