The illness usually begins with lethargy and a slowly rising fever over several days. After a fever-free interval the cycle repeats itself, either daily, every other day, or every third day or longer. The first attack lasts for about 1 month if left untreated. Subsequent relapses may occur over the ensuing years until partial or complete immunity results. The mosquito remains infectious for life.
Most species feed at dusk and during early night hours.
All travellers to subtropical and tropical destinations should consult a travel medicine clinic for assessment of their personal risk and appropriate preventive measures, if indicated.