Many cases of yellow fever are not diagnosed correctly because they occur in areas where dengue and chikungunya are endemic. Mild yellow fever symptoms are similar to both dengue and chikungunya. If jaundice develops, hepatitis is typically believed to be the cause.
The CDC can test serum for IgM antibodies and plaque-neutralizing antibodies. If blood is collected early enough in the disease, the virus can sometimes be cultured.
