Smallpox is caused by smallpox virus infectionAcute infectious diseaseHuman is the only host of smallpox virus.Smallpox virus includes large smallpox virus and small smallpox virus. Smallpox virus infected with large smallpox virus is more serious, with a mortality rate of 30%, while smallpox virus infected with small smallpox virus (also known as smallpox like/sub smallpox/small smallpox) has a lower mortality rate, about 1%.People who have not suffered from smallpox and who have not been vaccinated against smallpox belong to susceptible groups.
Smallpox virus mainly passes throughRespiratory transmissionas well asContact transmission。The incubation period of the virus is 10-14 days. After infection, the virus first propagates in the respiratory tract and then spreads to regional lymph nodes.About 7-11 days after infection, secondary viremia will appear, and patients will have obvious clinical symptoms, such asfever、headache、backache、tiredAnd so on, followed by characteristicMaculopapule。
The treatment of smallpox is mainly symptomatic and supportive, including maintaining the balance of body fluids and electrolytes, skin care and treatment of secondary bacterial infectionscomplication。Tecoviridat is the first antiviral drug used to treat smallpox.For complications, includingkeratitis、pneumoniaAnd doctors in relevant departments should be invited to deal with the symptoms.
Globally, smallpox has caused a large number of deaths. In the 20th century, smallpox caused 300 to 500 million deaths.However, due to the introduction and use of vaccines, smallpox has been successfully eliminated.Smallpox virus only exists in two safe freezers, namely the US Centers for Disease Control and Prevention in Atlanta and the Russian Virology and Biotechnology Vector Research Center in Korsovo, Siberia.world health organizationIn 1980, smallpox was officially declared extinct.
TCM disease name
smallpox
Foreign name
Smallpox, Variola
Visiting department
Infection Department, Infectious Disease Hospital
Multiple population
People who have not suffered from smallpox, who have not been vaccinated against smallpox, and whose immunity is lower than normal
Common diseases
Respiratory tract, skin
Common causes
Infection with smallpox virus
common symptom
Fever, headache, backache, fatigue, oral, facial and arm maculopapules, skin scab peeling
infectivity
yes
atlas
Science popularization in China
Committed to authoritative science communication
The certification expert of this term is
Zhao Hongqing|Chief physician
Wuxi Second People's Hospital Respiratory Departmentcompose
Smallpox is caused by infection with smallpox virus, which includes variola major and variola minor. Smallpox caused by infection with large smallpox virus is more serious, with a mortality rate of 30%, while smallpox caused by infection with small smallpox virus (known asSmallpox like/Subsmallpox/smallpox) has a low mortality rate of about 1%.
Infectious agent
Human is the only host of smallpox virus, and smallpox patients areInfectious agentIt is infectious from virus infection to scab formation, and is the most infectious during rash.Smallpox virus is very stable and canScabIt has survived for several years.Under natural conditions, smallpox virus is still pathogenic for several weeks.
Route of transmission
Respiratory transmission: Smallpox can be transmitted through the droplets generated by the patient's breathing, coughing, sneezing, etc., and can be infected by air when living with the patient in a narrow, closed space.
Contact transmission: Smallpox can be spread by contacting the patient's skin lesions (such as scab, blister fluid, etc.), and even by contacting the patient's clothes, bedding, etc.
Predisposing factors
People with lower immunity than normal (including those taking immunosuppressive drugs, AIDS patients, pregnant women, etc.) become more serious and have higher mortality after being infected with smallpox virus.
symptom
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The incubation period of smallpox is 10-14 days (7-19 days). After patients are infected with smallpox virus, the virus first propagates in the respiratory tract and then migrates to regional lymph nodes.Primary viremia is asymptomatic, and the virus can further migrate tospleen、bone marrowAnd distal lymph nodes.Secondary viremia occurs 7~11 days after infection, followed by fever, headache, backache and extreme fatigue, then maculopapule, which gradually turns into blister and pustule, and then the pustule crusts, leaving scars after desquamation.
according torashIt can be divided into common type, improved type, flat type, hemorrhagic type and variant type.
Typical course of disease (large smallpox)
Incubation period: no symptoms.
Virus like invasion period: it shows flu like symptoms such as high fever, chills, headache, backache, arthralgia, fatigue, etc. that suddenly start.
State stage: macular papules appear, first in the mouth, face and arms, and then quickly spread to the trunk and legs.The maculopapule festers rapidly, becomes blister on the third day, develops into pustule on the seventh day, and then crusts.
Drying period: if the patient survives, there will be a drying period on the 10th to 12th day, when the scab falls off and leaves permanent scars.
Smallpox like symptoms
In the 19th century, smallpox epidemic with weak toxicity occurred in South Africa and Central America, and the mortality rate was 1%. This kind of smallpox with weak toxicity was called smallpox like (also called sub smallpox, small smallpox).Its initial symptoms are similar to smallpox, but not so serious and extensive.
Symptoms of hemorrhagic smallpox
About 5%~10% of people infected with smallpox virus have hemorrhagic or malignant (flat) rashes, typically manifested as fused flat non pustular skin lesions and skin and/or mucosal bleeding, which are almost always fatal (mortality rate 97%). Patients often die of organ failure symptoms after the first 24 hours of the invasion period.
Medical treatment
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world health organizationIt has been announced that smallpox has been eliminated, so smallpox patients will not appear generally.However, if smallpox is suspected, it must be diagnosed through blood tests and skin tests.Once smallpox is confirmed, it will become a global public health emergency. Disease control departments need to take immediate action to isolate patients and people in contact with it.
Visiting department
Infection department or infectious disease hospital
Relevant inspection
Medical history and physical examination
Prevalence: whether smallpox is prevalent;Whether there is smallpox virus laboratory work exposure;
Personal history: age, previous physical condition, whether you have been vaccinated against smallpox, and whether you have been exposed to smallpox patients;
Conscious symptoms: whether there are high fever, fatigue, headache, backache and other symptoms, and whether there is a certain regularity of rash;
Physical examination: whether typical skin lesions (including maculopapules, herpes, pustules, etc.) can be seen.
Immunological examination
Complement fixation test;
Erythrocyte agglutination inhibition test;
Neutralization test.
Etiological examination
Electron microscope: It can be used to observe smallpox virus.
Polymerase chain reaction (PCR): used to detect viral DNA.
differential diagnosis
Monkeypox virusInfection can also cause symptoms similar to smallpox, which needs to be identified by pathogenic examination.
treatment
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Smallpox treatment is mainly symptomatic support treatment, including maintaining fluid and electrolyte balance, skin care and treatment of secondary bacterial infections and other complications.
General treatment
Strict isolation
People infected with smallpox virus must be strictly isolated until they are cured;
The patient's clothes, bedding and other articles should be strictly disinfected;
Persons who have ever come into contact with patients or their supplies should also be isolated for observation and vaccinated against smallpox.
Supportive treatment
To ensure the nutritional supply of patients, intravenous nutrition is available when necessary.
medication
Tecovirimat, the first antiviral drug used to treat smallpox, was approved for use in the United States in July 2018.
Symptomatic support treatment
Patients with bacterial infection can be treated with antibiotics.
High fever patients can use drugs to cool down, such as non steroidal anti-inflammatory drugs, acetaminophen, ibuprofen and other drugs.
Patients with obvious pain can use pain killers.
Skin rashes can be consulted by dermatologists and treated symptomatically with drugs.
Patients with corneal ulcer and oral ulcer can consult with ophthalmologists and stomatologists for symptomatic treatment.
Other treatments
Treatment of complications: For patients with meningitis, osteomyelitis, pneumonia and other complications, doctors in relevant departments should be invited to take appropriate measures to alleviate the pain of patients.
prognosis
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Different types of smallpox have different prognosis. The mortality rate of typical smallpox (large smallpox) is about 30%, that of smallpox like smallpox (small smallpox) is about 1%, and that of hemorrhagic smallpox is as high as 97%.If they can survive, they can get lifelong immunity.
complication
Smallpox patients can have a variety of complications, such as secondary bacterial infection of the skin, keratitis and corneal ulcer leading to blindness, viral arthritis and osteomyelitis, bacterial pneumonia, orchitis, encephalitis, etc.
