Schistosomiasis (also known as Bilharzia, snail fever, or Katayama fever) is caused by flatworm parasites that live in the blood vessels of the bladder and intestines. Schistosomiasis - also known as bilharzia, snail fever, or Katayama fever - is caused by flatworm parasites that live in the blood vessels of the bladder and intestines. Health Matters
A Tornado warning means A tornado has been  spotted/touched down in your alert area. You should take  cover if a tornado warning is issued for your area;  go into a cellar, or the lowest, most inner part of your house  where there are no windows (a downstairs or basement bathroom is  ideal).
Tornadoes are much harder to forecast than hurricanes, which are larger storms that last a lot longer. According to NOAA, the average amount of time between a tornado warning and the arrival of a storm is about 13 minutes. (A tornado warning means a twister has been sighted, while a tornado watch means one is possible.)