How long is a toddler with herpangina contagious?

Several weeks: The causes of herpangina vary but generally children are contagious up to a week before there even symptomatic and can still spread the virus several weeks after the initial infection. Good hand hygiene with frequent handwashing with soap and water is very important in decreasing the spread of this viral infection since it can be spread for so long.

During the fever: The primary contagious period is during the fever fluctuations over the first few days. Saliva is teeming with virus as is the poop. After the fever fades the saliva clears but the virus can be detected in poop for weeks. This is one reason it spreads so easily in day care centers.