Rotavirus Epidemiology

Rotavirus is a common childhood diarrheal illness, with 95% of children ages 3-5 having already contracted the virus. It is also the most severe. It causes 1/3 of diarrhea associated deaths and kills more than 873,000 children worldwide. 2.7 million children age 5 and younger are affected each year in the United States alone, causing 150 deaths, 500,000 doctor visits, 50,000 hospitalizations, and $274 million in medical care and $1 billion in societal costs. The huge numbers of infected individuals stem from the fact that 10 ¹⁰ particles per gram of feces are shed for 3-7 days in normal individuals. The length of time is even greater in immunocompromised individuals. Rotavirus is highly infectious and a dose of less than 100 particles is enough to lead to infection and cause disease. 95% of Rotavirus isolates are from serotypes 1, 2, 3 and 4.

The virus is spread mainly by contact with feces and while it can be decreased by increased hygiene, this technique has proved virtually impossible in young children. It may also be spread through respiratory secretions, person to person contact, or contaminated environmental surfaces, such as diaper pails and toys, as there are high rates of infection even in the most sanitary conditions. Noscomial infections are quite common as well as waterborne epidemics, as Rotaviruses are resistant to chlorination. They have an incubation period of less than 48 hours.

The virus tends to peak in winter and fall in temperate climates. In the US, Rotavirus activity starts in the Southwest in autumn and moves to the Northeast by Spring. In the tropics the virus tend to be endemic year-round.

Rotavirus activity by season in the United States July 1991-June 1997. Reprinted from Emerging Infectious Diseases Volume 4 Number 4 Oct-Dec 1998.

Rotaviruses have been found all over the world. Developing countries are particularly hard hit by Rotavirus, with an average of 2000 children dying each day from Rotavirus infection. Nutrition seems to play a large role in the mortality rates of this virus, as those children already in distress face much more severe symptoms when infected. Death by Rotavirus may be prevented by either Oral Rehydration therapy which replaces lost electrolytes in the child or by a vaccine that has just recently (Aug. 1998) been approved by the FDA.

Global Distribution of deaths caused by Rotavirus. Reprinted from Emerging Infectious Diseases Volume 4 Number 4 Oct-Dec 1998.

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