For example, x-ray and CT scans of the chest can be used to detect lesions in the lungs from pulmonary schistosomiasis, and pelvic x-ray can reveal calcification of the bladder in chronic urinary schistosomiasis. Ultrasound may be used to look for abnormalities in the liver and spleen in hepatosplenic schistosomiasis, and CT scan of the liver is a good tool to look for calcification in the liver associated with S. japonicum infection. CT scan can also be used to assess damages from the schistosomiasis infection in the intestinal, urogenital, and central nervous system. MRI is used to evaluate schistosomiasis of the central nervous system, liver, and genital.PET/CT scan that identifies tissues with higher metabolic activity have been used to help diagnose schistosomiasis in rare cases. This is due to the high level of inflammation caused by the schistosomal eggs, which increases the metabolic rate of the surrounding tissues. Prevention
Many countries are working towards eradicating the disease. The World Health Organization is promoting these efforts. In some cases, urbanization, pollution, and the consequent destruction of snail habitat have reduced exposure, with a subsequent decrease in new infections. The elimination of snail populations using molluscicides had been attempted to prevent schistosomiasis in the past, but it was an expensive process that often only reduce but not eliminate the snail population. The drug praziquantel is used for prevention in high-risk populations living in areas where the disease is common.
Transmission and life cycle
Infected individuals release Schistosoma eggs into water via their fecal material or urine. After larvae hatch from these eggs, the larvae infect a very specific type of freshwater snail. For example, in S. haematobium and S. intercalatum it is snails of the genus Bulinus, in S. mansoni it is Biomphalaria, and in S. japonicum it is Oncomelania. The Schistosoma larvae undergo the next phase of their lifecycles in these snails, spending their time reproducing and developing. Once this step has been completed, the parasite leaves the snail and enters the water column. The parasite can live in the water for only 48 hours without a mammalian host. Once a host has been found, the worm enters its blood vessels. For several weeks, the worm remains in the vessels, continuing its development into its adult phase. When maturity is reached, mating occurs and eggs are produced. Eggs enter the bladder/intestine and are excreted through urine and feces and the process repeats. If the eggs do not get excreted, they can become engrained in the body tissues and cause a variety of problems such as immune reactions and organ damage. While transmission typically occurs only in countries where the freshwater snails are endemic, a case in Germany was reported where a man got Schistosoma by an infected snail in his aquarium.Humans encounter larvae of the Schistosoma parasite when they enter contaminated water while bathing, playing, swimming, washing, fishing, or walking through the water.