Enterovirus 71 has caused epidemics associated with significant morbidity and mortality. However, its transmission has not been thoroughly investigated.
In this study, researchers from Taiwan investigated enterovirus 71 transmission and determine clinical outcomes within households.
The team assessed patients at a children's hospital in Taiwan and their family members had symptoms suggestive of enterovirus 71.
The patients and the members of their household underwent clinical evaluations, virological studies, and questionnaire-based interviews. They were followed up for 6 months.
The team confirmed enterovirus 71 infection using either positive viral culture from a throat or rectal swab, or the presence of IgM or a 4-fold increase in neutralizing antibody in serum. Clinical syndromes were defined as asymptomatic, uncomplicated symptomatic, or complicated.
The researchers identified 94 families (433 family members) with at least 1 family member who had evidence of enterovirus 71 infection.
|21% of children had complicated syndromes.|
|Journal of the American Medical Association|
They found that overall enterovirus 71 transmission to other household members was 52%.
The team calculated the transmission rates as 84% for siblings, 83% for cousins, 41% for parents, 28% for grandparents and 26% for uncles and aunts.
Of the 183 infected children, 6% were asymptomatic and 3% had uncomplicated illnesses. Uncomplicated illness included hand, foot, and mouth disease, herpangina, nonspecific febrile illness, upper respiratory tract infection, enteritis, or viral exanthema.
The team determined that 21% of children had complicated syndromes, including central nervous system or cardiopulmonary failure.
During the 6-month follow-up, they found that 10 children died and 13 had long-term sequelae consisting of dysfunction in swallowing, cranial nerve palsies, central hypoventilation, or limb weakness and atrophy.
The team found that age younger than 3 years was the most significant factor associated with an unfavorable outcome.
Of the 87 infected adults, 53% were asymptomatic, 39% had nonspecific illnesses of fever, sore throat, or gastrointestinal discomfort, and 8% had hand, foot, and mouth disease.
There were no complicated cases in adults.
Dr Luan-Yin Chang's team concluded, "Enterovirus 71 household transmission rates were high for children in Taiwan".
"Severe disease with serious complications, sequelae, and death occurred frequently".
"In contrast, adults had a much lower rate of acquisition of the infection and much less adverse sequelae".