In Egypt, 60% of the population in the Northern and Eastern parts of the Nile Delta and only 6% in the Southern part are infected.S. mansoni is commonly found in places with poor sanitation. Because of the parasites fecal-oral transmission, bodies of water that contain human waste can be infectious. Water that contains large populations of the intermediate host snail species is more likely to cause infection. Young children living in these areas are at greatest risk because of their tendency to swim and bathe in cercaria-infected waters longer than adults
. Anyone travelling to the areas described above, and who is exposed to contaminated water, is at risk of schistosomiasis. History
The intermediate hosts Biomphalaria snails are estimated to originate in South America 95–110 million years ago. But the parasites Schistosoma originated in Asia. In Africa, the progenitor species evolved into modern S. mansoni and S. haematobium around 2–5 million years ago.A German physician Theodor Maximillian Bilharz was the first to discover the parasite in 1851, while working at Kasr el-Aini Hospital, a medical school in Cairo. Bilharz recovered them from autopsies of dead soldiers, and noticed two distinct parasites. He described one of them as Distomum haematobium (now S. haematobium) in 1852, but failed to identify the other. In one of his letters to his mentor Karl Theordor von Siebold, he mentioned some of the eggs were different in having terminal spines while some had lateral spines. Terminal-spined eggs are unique to S. haematobium, while lateral spines are found only in S. mansoni.
From there it continues to spread, eventually getting into the blood and spreading to more lung tissue, as well as other organs like the intestines and the brain. Functional impairment of the infected dendritic cells by the measles virus is thought to contribute to measles-induced immunosuppression. Diagnosis
Typically, clinical diagnosis begins with the onset of fever and malaise about 10 days after exposure to the measles virus, followed by the emergence of cough, coryza, and conjunctivitis that worsen in severity over 4 days of appearing. Observation of Kopliks spots is also diagnostic. Other possible condition that can result in these symptoms include parvovirus, dengue fever, Kawasaki disease, and scarlet fever. Laboratory confirmation is however strongly recommended. Laboratory testing
Laboratory diagnosis of measles can be done with confirmation of positive measles IgM antibodies or detection of measles virus RNA from throat, nasal or urine specimen by using the reverse transcription polymerase chain reaction assay. This method is particularly useful to confirm cases when the IgM antibodies results are inconclusive. For people unable to have their blood drawn, saliva can be collected for salivary measles-specific IgA testing. Salivary tests used to diagnose measles involve collecting a saliva sample and testing for the presence of measles antibodies. This method is not ideal, as saliva contains many other fluids and proteins which may make it difficult to collect samples and detect measles antibodies. Saliva also contains 800 times fewer antibodies than blood samples do, which makes salivary testing additionally difficult.