The main manifestations are severe viremia and high mortality after infection. Smallpox virus mainly invades human body through respiratory mucosa, and spreads through droplet inhalation or direct contact.
The course of typical smallpox can be divided into three stages: precursor stage, eruption stage and scab stage.
1, prodromal period, lasting for 3 ~ 4 days, with acute onset, chills, high fever, fatigue, photophobia, headache, pain in back and limbs, abdominal pain; Some patients may have mild symptoms of upper respiratory tract inflammation. Children may be accompanied by vomiting. High fever can last for 2 ~ 5 days.
The patient is seriously ill, with painful expression, conjunctival congestion, sometimes tears, mild swelling of liver and spleen, etc. On the first 1 ~ 2 days of fever, transient "prodromal rash" can appear in the lower abdomen, groin, inner thigh, both sides of waist and abdomen and armpit, showing measles-like, scarlet fever rash-like, urticaria-like or bleeding; Because the number is small, it will retire in a few hours, so it is easy to be ignored.
2. During the eruption period, the time, location and sequence of smallpox eruption have certain rules. On the 3 rd to 4 th day of onset, the body temperature dropped slightly; At this time, a rash appeared. It spread rapidly from the face to the neck, forearm, upper arm, hand, chest, abdomen, lower limbs and soles of feet, and spread to the whole body within 1 ~ 2 days.
The rash is distributed centrifugally, mainly in the exposed parts such as head, limbs, etc. The upper body is more than the lower body, and there is little or no rash under the armpit and waist.
3, scabbing stage, starting to scab after 2 to 4 weeks of illness, leaving scars.
Extended data
Type A smallpox (known as the common type) is found in people who have never been vaccinated against vaccinia. The specific symptoms are as follows:
The incubation period is usually 8 ~ 12 days, with sudden onset, high fever, headache, vomiting and other systemic symptoms. Transient measles-like or scarlet fever-like rashes (prodromal rashes) may appear on lower limbs, inner thighs, armpits and waist/0/~ 2 days after onset.
On the 3rd to 4th day, the body temperature dropped rapidly, and the symptoms were relieved. At the same time, there is a rash with centrifugal distribution, that is, the head, face and extremities are denser than the trunk. At first, it was a dark red macula, which turned into a papule after a few hours, and became a blister on the 6 th to 7 th day of onset.
The center is sunken and the periphery is red. At this time, rashes also appeared in the mouth, throat, canthus and conjunctiva. On the 8th to 9th day, the blister turned into pustule, at which time the body temperature rose again and the poisoning symptoms became worse. On the 8th to 9th day of onset, pustules gradually dried up, forming a thick yellow-green scab.
Consciously itchy, the body temperature gradually dropped, and the general condition improved. After 2 ~ 4 weeks of illness, scabs began to form, leaving scars.
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