As folate is vital in the first trimester of pregnancy for healthy fetal development, the use of antifolates is strongly contraindicated in pregnancy and carries significant teratogenic risk. Low doses of methotrexate can deplete folate stores and cause side-effects that are similar to folate deficiency.
Cause of Adult Mumps. Adult mumps is caused by an infection with the mumps virus, which is found worldwide. The mumps virus is an RNA (ribonucleic acid) virus from the family Paramyxovirus of the genus Rubulavirus. The mumps virus only infects humans.
Encephalitis can occur with certain childhood viral illnesses, such as mumps, measles, varicella (chicken pox), rubella (German measles), or mononucleosis. A much more serious type of encephalitis is caused by the herpes simplex virus * (HSV).HSV rarely infects the brain, but when it does, it can be life threatening. West Nile virus, which first arrived in the United States from other parts of the world in the late 1990s, can cause encephalitis as well.ncephaliti s may be caused by a variety of viruses, bacteria, and other organisms. These agents include:. 1  Measles, chicken pox, rubella (German measles), mumps, polio, and other viral illnesses, which generally lead to a mild form of encephalitis known as postinfectious or para-infctious encephalitis.