1911 Encyclopædia Britannica/Bilharziosis
BILHARZIOSIS. In various parts of Africa the inhabitants are liable to suffer from a form of endemic haematuria caused by the presence of a parasite in the mucous membrane of the urinary passages. This parasite was discovered in 1852 by Bilharz, and hence is generally known as Bilharzia, though it has been more scientifically named Schistosoma haematobium. The condition to which it gives rise is that of bilharziosis. (For description and life history of the parasite see Trematodes.) In man the parasites and ova have been found in the minute veins of the bladder, ureter and pelvis of the kidney (more rarely in other organs), where they infest the mucous and submucous tissues. In an affected bladder the mucous membrane presents swollen vascular patches of varying size, or warty prominences on which the urinary salts may be deposited. The ova often serve as a nucleus for urinary calculi. Similar changes may take place in the ureter, and the consequent swelling lead to obstruction to the passage of urine, and if left untreated to pyelitis and pyonephrosis. If the rectum be affected the mucous membrane becomes thickened, polypoid growths form and large submucous haemorrhages may take place.
As to the mode of entrance of this parasite opinion is divided. Some authorities favour the view that the entrance is through the skin, urethra or rectum, the result of bathing in infected water; others that it is taken by the mouth in water or uncooked fish. The symptoms to which it gives rise are haematuria, pain in the perineal region and a greater or less degree of anaemia through loss of blood. If the disease continue, cystitis and its consequent train of symptoms ensue (see Bladder and Prostate Diseases). If the rectum be affected there is considerable discharge of mucus, and later prolapsus ani may be the result. But the symptoms vary to a remarkable extent, from the slightest producing but little discomfort, to the most severe resulting in death. The liquid extract of male fern is the only drug used with much success. The symptoms caused by the parasite must be treated as they arise. Polypoid growths of the rectum must be surgically treated.