Schistosomiasis has a long history of prevalence and causes severe harm in China. It was once widely distributed in 12 provinces (autonomous regions and municipalities) south of and along the Yangtze River， including Shanghai， Jiangsu， Zhejiang， Anhui， Fujian， Jiangxi， Hubei， Hunan， Guangdong， Guangxi， Sichuan， and Yunnan. Among these， Japan-related schistosomiasis is currently the prevalent form in China. This parasitic disease is caused by infection with *Oncomelania hupensis* cercariae (the larval stage)， with the adult worms parasitizing the portal venous and mesenteric venous systems of humans and various mammals.
During flood seasons， natural disasters like floods can lead to unavoidable contact between people or livestock and “epidemic water” containing *Oncomelania hupensis* cercariae， resulting in schistosomiasis infection.
Based on epidemiological history， clinical manifestations， and laboratory examination results， schistosomiasis can be classified into acute schistosomiasis， chronic schistosomiasis， and late-stage schistosomiasis. Acute schistosomiasis receives significant attention due to the strong bodily reactions of patients， which can be fatal if left untreated.
Characteristics of Acute Schistosomiasis
1. Large Infection Dose
This is common in individuals experiencing their first infection. Chronic patients can also develop acute symptoms after a subsequent heavy exposure to cercariae. The incubation period varies from 14 to 84 days， with an average of about 40 days. A significant parasitic load is often the precursor to severe symptoms.
2. Fever and Allergic Reactions
Fever is the main symptom of acute schistosomiasis. The fever pattern and duration are related to the severity of the infection and the patient’s immune status， often showing poor response to common antipyretic medications. Some patients experience severe systemic allergic reactions， manifesting as urticaria (hives)， angioedema (swelling of the face， limbs)， and enlarged lymph nodes. These reactions indicate a robust immune response to the invading parasites.
3. Respiratory and Gastrointestinal Reactions
Respiratory symptoms include cough (often dry)， chest pain， and difficulty breathing. Gastrointestinal symptoms encompass severe abdominal pain (frequently around the navel)， abdominal distension， diarrhea (often with mucus or blood)， nausea， vomiting， and significant， tender enlargement of the liver within a short period. Splenomegaly (enlarged spleen) can also occur rapidly in some patients. The rapid hepatomegaly suggests acute inflammation and possibly congestion.
4. High Misdiagnosis Rate
Due to symptoms like fever， enlarged liver， and diarrhea， which are very similar to those of diseases such as typhoid fever and sepsis， acute schistosomiasis is easily misdiagnosed， especially in non-epidemic areas or when medical professionals lack high vigilance. This highlights the importance of a detailed patient history， including potential exposure to endemic areas or water.
How to Prevent Acute Schistosomiasis?
1. Avoid Contact with Epidemic Water as Much as Possible
During flood seasons， natural disasters can cause water bodies to overflow， expanding the range of water contaminated with schistosomiasis cercariae. When people engage in flood control， swimming， playing in water， washing hands and feet， laundry， washing vegetables， or agricultural labor during flood periods， they are prone to contact with epidemic water. Cercariae can penetrate the skin， leading to schistosomiasis infection.
Preventing contact with epidemic water is an effective way to prevent schistosomiasis. If contact cannot be avoided， protective gloves should be worn before entering the water， and protective ointments like “Fenghu Ling” should be evenly applied to the skin. This provides a physical and chemical barrier against cercarial penetration.
2. Do Not Engage in Activities on Shelled Snail Beaches
Oncomelania snails are the intermediate hosts for *Oncomelania hupensis*. Under natural disasters like floods， these snails can be dispersed to new areas via water flow. Infected snails release cercariae into the water， and when humans or livestock come into contact with this epidemic water， they can become infected with schistosomiasis. Avoiding activities on beaches where shelled snails are present effectively prevents schistosomiasis infection. This underscores the crucial role of snail control in schistosomiasis elimination efforts.
3. Do Not Drink Raw Water
Due to continuous rainfall and other reasons， water sources can become contaminated. If people drink raw water containing schistosomiasis cercariae， they may become infected. Therefore， avoiding drinking raw water reduces the risk of schistosomiasis infection. For temporary water supplies， 0.5 grams of bleaching powder essence or 1 gram of bleaching powder can be added per 50 kilograms of water， with use after 30 minutes of treatment. Drinking water must be boiled before consumption. This is a fundamental safety measure for water hygiene.
4. Proper Fecal Management
The feces of schistosomiasis patients and infected livestock usually contain schistosoma eggs. These eggs can only hatch in water. Therefore， proper management of human and animal feces， safe grazing practices， and preventing feces from entering water bodies can effectively block the transmission of schistosomiasis. This involves the safe disposal of human and animal waste to prevent environmental contamination.
What to Do if Diagnosed with Acute Schistosomiasis?
If symptoms suggestive of acute schistosomiasis appear， seek examination at a disease prevention and control institution as soon as possible and disclose any potential exposure history for timely detection， diagnosis， and treatment. Diagnosis of schistosomiasis typically involves immunological， etiological， and imaging examinations. Patients with acute schistosomiasis require hospitalization and the standardized use of the anti-parasitic drug Praziquantel under medical guidance， along with symptomatic treatment.
