Popular among rats, land sloths and other rodents Main manifestations: high fever (residual fever), lymph node swelling and pain, bleeding tendency, special inflammation of the lungs Bacteria-carrying rat fleas act as vectors in humans There are 12 types of international quarantine infectious diseases and natural foci distributed in 19 provinces, mainly bubonic plague.

Yersinia pestis, Gram-negative, encapsulated, non-flagellated, non-sporulating

Capsular antigens and virulence V/w antigens; produce murine toxins and endotoxins

The external environment has weak resistance, moisture, low temperature, and organic matter has a longer survival time.

Source of infection: mice and other rodents; Chlorophytum genus and Slothia are the main reservoir hosts; Rattus norvegicus and Rattus yellow-breasted are the main sources of plague in humans

Transmission routes: Plague transmission between animals and humans; skin-to-skin transmission; respiratory droplet transmission

Population susceptibility: universal susceptibility; invisible infection, long-lasting immunity; vaccination

Epidemic characteristics: my country is mainly the foci of yellow-breasted plague in western Yunnan and the foci of drought in the Himalayas on the Qinghai-Tibet Plateau. Mostly spread from epidemic areas through transportation. Human plague epidemics all occur after animal plague. Human plague is mostly transmitted from the wild to domestic rats. Human plague usually occurs from June to September. Pneumonic plague usually occurs after October Differences in occupational infectivity are related to the opportunity and frequency of exposure to infectious agents

After invading through the skin, it is phagocytized by neutrophils and monocytes-macrophages, and rapidly multiplies from lymph nodes to local lymph nodes, causing primary lymphadenitis. It travels through the blood to lung tissue, causing secondary pneumonic plague.

Basic pathological changes: hemorrhagic inflammation and coagulative necrosis

Incubation period: 2-5 days for bubonic plague. Primary pneumonic plague lasts from several hours to three days. 9-12 days for vaccinated persons

Bubonic plague: swollen lymph nodes at the site of invasion; swollen inguinal, axillary, cervical and submandibular lymph nodes, mostly unilateral, hard and painful

Pneumonic plague: sudden onset, chills and high fever, 24-36 hours, cough and frothy pink bloody sputum

Septicemic plague: fulminant plague, characterized by chills, high fever, and purple-black color after death, so it is called the Black Death.

Mild: people at the beginning or end of the epidemic or those who have been vaccinated

Blood routine: elevated white blood cells, elevated lymphocytes, elevated neutrophils, and decreased blood cells. Urine: proteinuria, hematuria Feces: occult blood Coagulation function: prolonged Cerebrospinal fluid: increased meningitis-type white blood cells and increased protein

Smear test: hematuria cerebrospinal fluid; Brevibacterium

Bacterial culture isolation: lymphocentesis fluid

Serology: Convalescent antibodies increased 4-fold

Have been to plague-endemic areas within 10 days, have a history of contact with suspected plague animals or patients, have a sudden onset of illness, high fever, and have plague symptoms

The case fatality rate is extremely high due to the timely application of antibiotics

General treatment and care

Pathogen treatment: streptomycin; early combined with adequate dose for sensitivity

Symptomatic treatment

Management of sources of infection: Isolate bubonic plague until 7 days after the lymphadenopathy has dissipated, and isolate pneumonic plague until 6 negative sputum cultures are obtained; contacts should be under medical observation for 9 days, and those who receive vaccinations should be quarantined for 12 days, and related supplies should be disinfected and incinerated.

Cut off the transmission route: strengthen quarantine, conduct strict quarantine on transportation vehicles coming from epidemic areas, eliminate rats and fleas, and isolate and quarantine suspicious passengers

Protect susceptible groups: strengthen personal protection, preventive medication, and vaccination (can enter the epidemic area 10 days after vaccination)