The presence of an arbovirus in a particular area depends on the availability of specific types of mosquitoes that can carry it and specific birds or animals that can be infected. More than 100 arboviruses cause disease in humans. Most of these are classified into groups, or families. Each causes specific types of illness. These are some examples.
Most infected people have no symptoms.
When symptoms occur, they usually start suddenly, with fever, chills, headache, muscle aches, and tiredness. Symptoms of encephalitis are drowsiness, stiff neck, confusion, convulsions, tremors, and coma. Symptoms of hemorrhagic fever include signs of internal bleeding, which can lead to shock and sometimes death. The time between exposure and symptoms can vary from 3 to 21 days. Complications of encephalitis can be serious, and include coma, permanent brain damage, and death.