Which category of infectious diseases does Class A infectious diseases belong to?

Class A infectious diseases include highly virulent diseases such as cholera and plague, both of which are extremely contagious. Upon detection of a Class A infectious disease, immediate isolation and medical treatment are required.

Cholera typically presents with severe, painless watery diarrhea, with some patients experiencing more than ten episodes of diarrhea per day. If not properly treated, cholera can rapidly lead to severe dehydration and death. Cholera patients or carriers excrete large amounts of the cholera bacterium in their feces, which spreads widely through contaminated water, leading to outbreaks affecting many people. Treatment should be conducted under medical supervision, with commonly used medications including compound sulfamethoxazole tablets and pipemidic acid capsules.

Plague is caused by *Yersinia pestis* and is associated with high risk and severity, as well as an extremely high mortality rate. Rodents are the primary transmission route; fleas first bite infected animals and then transmit the pathogen to humans through subsequent bites. Plague can also spread via respiratory droplets from infected individuals, posing even greater danger. Symptoms include high fever, swollen lymph nodes, and hemorrhaging, and historically, the fatality rate has been very high. Plague can be managed through supportive care and antimicrobial therapy.

If infected with a Class A infectious disease, mandatory isolation is required to prevent further transmission. During treatment or visitation, strict protective measures must be taken to avoid contact with the infectious agent.