Measles has immediate cause Measles virus
Cause
Measles is caused by the measles virus, a single-stranded, negative-sense, enveloped RNA virus of the genus Morbillivirus within the family Paramyxoviridae.The virus is highly contagious and is spread by coughing and sneezing via close personal contact or direct contact with secretions. Measles is the most contagious virus known. It remains infective for up to two hours in that airspace or nearby surfaces. Measles is so contagious that if one person has it, 90% of non-immune people who have close contact with them (e.g., household members) will also become infected. Humans are the only natural hosts of the virus, and no other animal reservoirs are known to exist, although mountain gorillas are believed to be susceptible to the disease.
Risk factors for measles virus infection include immunodeficiency caused by HIV/AIDS, immunosuppression following receipt of an organ or a stem cell transplant, alkylating agents, or corticosteroid therapy, regardless of immunization status; travel to areas where measles commonly occurs or contact with travelers from such an area; and the loss of passive, inherited antibodies before the age of routine immunization.
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