Schistosomiasis (Bilharzia or snail fever)
什么是Schistosomiasis (Bilharzia or snail fever)？
Schistosomiasis (also called bilharzia or snail fever) is a parasitic disease caused by certain species of water-borne flatworms or blood flukes. These parasites are known as schistosomes.
An increasing number of tourists are acquiring the disease with the increased popularity of eco-tourism and travelling off the beaten path.
如何获得Schistosomiasis (Bilharzia or snail fever)？
Schistosomiasis is usually contracted by people in developing countries while fishing or farming in contaminated water. The parasite easily enters through intact skin and matures within organ tissues.
易感性和抗性
Anyone who travels to an endemic area and is exposed to fresh water sources (usually rivers or lakes) is susceptible to schistosomiasis. Some people who have had shistosomiasis may develop a variable degree of immunity to reinfection, but the duration of any immunity to this illness has not been fully documented.
症状是什么？
Schistosomiasis is mainly a chronic infectious disease. Many infections do not produce symptoms. However, acute schistosomiasis may include the following symptoms: diarrhoea, fever, fatigue, abdominal pain, blood in the stool, eosinophilia (increased white blood cell count), hepatosplenomegaly (enlargement of the liver or spleen).
Late complications of schistosomiasis from chronic infection can include:
- _S. haematobium _can cause urinary symptoms such as dysuria (painful urination), hematuria (blood in the urine), and frequent urination.
- Obstructive uropathy (condition in which the flow of urine is blocked, injuring the kidneys)
- Infertility
- Portal hypertension (high blood pressure in the portal vein in the abdominal cavity)
- Liver fibrosis (formation of excess scar tissue in the liver)
- Colonic polyposis (abnormal growths in the colon)
- Rarely, S. japonicum can cause seizures and lesions in the central nervous system.
- There is an increased risk of bladder cancer associated with urinary schistosomiasis. The larva of some schistosomes may cause a rash sometimes known as “swimmer’s itch”; however, these schistosomes do not cause schistosomiasis as they do not mature within humans.
预防措施
降低与血吸虫接触的风险的最佳方法是避免在血吸虫常见的地区通过游泳，沐浴，涉水或参加农业活动与污染的水接触。
处理
Schistosomiasis is easily treatable with a single dose of the drug Praziquantrel annually. Alternative drugs include oxamniquine to treat S. mansoni, and metrifonate to treat S. haematobium.
药物
它常见于哪里？
在世界的不同地方发现了不同种类的血吸虫：-_S。在非洲，地中海东部，加勒比海和南美都发现了mansoni_。 -_S。 japonicum_在中国，菲律宾和印度尼西亚的苏拉威西（Celebes）中发现。 -_S。 haematobium_发生在非洲和东地中海。 -_S。 mekongi_位于柬埔寨和老挝人民民主共和国的湄公河地区。 -_S。 intercalatum_发生在非洲西部部分地区，包括喀麦隆，乍得，刚果民主共和国，加蓬和圣多美。 -_S。 malayensis_仅在马来西亚半岛发现。 -人感染牛寄生虫_S。据报道，南部非洲有马太伊。
