Rotavirus Facts
Rotavirus is the most common cause of severe, dehydrating diarrhea among children worldwide. Each year it causes:
- About 111 million cases of disease requiring home care only
- 25 million clinic visits
- 2 million hospitalizations
- more than 500,000 deaths in children aged five or younger.*
Read more Facts about Rotavirus and Questions and Answers about Rotavirus.
Populations At Risk
Every child in the world will have at least one rotavirus infection before age five. In industrialized nations like the US, around 70 child deaths are attributed each year to this diarrheal disease. In developing countries, however, nearly 1,400 children die from rotavirus infections each day, succumbing to severe dehydration that could be easily treated if they had access to lifesaving care often routine in richer nations.
Children six months to two years of age are most vulnerable to rotavirus infection, along with premature infants, the elderly, and those with weakened immune systems. Rotavirus in otherwise healthy adults tends to be mild.
Rotavirus in Developing Countries
Children in the poorest countries account for 85% of rotavirus deaths.*
Many factors contribute to children in poor countries carrying this disproportionate burden, including increased malnutrition and limited access to advanced therapy needed to replace the fluids lost through diarrhea and vomiting.
Global Distribution of Rotavirus Mortality
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Nature of the Disease
Rotavirus can be mild or severe. Its incubation period is about two days. The disease causes vomiting and watery diarrhea for 3 to 8 days, and frequently includes fever and abdominal pain.
Infection appears to provide partial immunity, as repeat infections tend to be less severe. This disease pattern makes researchers believe that a vaccine could protect against the severe disease and death caused by rotavirus.
Transmission
A person with rotavirus diarrhea often excretes large amounts of virus, which can spread readily through contaminated hands. Rotavirus, a hearty virus that survives easily in the environment, can also be transmitted through contaminated objects, water, or food.
However, scientists suspect that rotavirus may be transmitted through the air as well, since the virus has been detected in respiratory tract secretions of sick children.
Improvements in sanitation and hygiene that stop many bacteria and parasites has not prevented the transmission of rotavirus.
A universal childhood vaccine may be the best means to prevent rotavirus disease.
Treatment
Neither antibiotics nor other drugs can cure rotavirus.
The only treatment consists of preventing dehydration by providing fluids and salts until the disease runs its course. In the most serious cases, frequent vomiting makes oral rehydration ineffective. Children who cannot keep down fluids urgently need intravenous fluids, or they risk dying from dehydration.
While illness is usually mild enough that parents can care for their children at home, about one in 65 cases requires hospitalization for intravenous fluids.*
The poorest developing countries may lack hospital and laboratory facilities to meet this need. Where such care is unavailable, death rates are highest.
Preventing serious disease in the first place is the best way to protect children in poor countries.
The Virus
First recognized in 1973, rotavirus belongs to the viral family Reoviridae. Its wheel-like shape under an electron microscope earned it the name of “rota” virus.
The rotavirus genome consists of 11 double-stranded RNA segments, each encoding one viral protein. A triple-layered capsule surrounds the RNA.
Scientists have described seven rotavirus groups (A to G). Only groups A, B, and C infect humans. Group A, which has multiple strains, causes the majority of childhood infections. Vaccine candidates are designed to protect against Group A rotaviruses.
Rotavirus infection has also been detected in many species of domestic animals, wild mammals, and birds.
Diagnosis
Health workers diagnose the disease by identifying the virus in the patient’s stool. The standard protocol for hospital-based surveillance of rotavirus requires testing stool for rotavirus using a commercial enzyme immunoassay kit. The kit is the most cost-effective and labor-efficient way to identify the virus. Without such positive identification, it is impossible to determine which of several possible pathogens may be the cause of the patient’s diarrhea.
Why Children Face Higher Risk
Although humans of all ages are susceptible to rotavirus infection, children 3 to 24 months of age account for the vast majority of severe infections. Why does rotavirus hit this age range so hard? It is believed that maternal antibodies protect younger infants, and older children may have built up immunity from repeated earlier infections.
Premature infants, the elderly, and the immunocompromised are also more prone to severe symptoms.
Cause of Clinical Disease
Rotavirus replicates in certain cells that line the inside of the small intestine. This replication decreases the ability of the intestine to absorb salts and water. Rotavirus has never been detected consistently in the blood or in other sites far from the intestine.
* Source: Parashar U, Gibson C, Bresee J, Glass R. Rotavirus and severe childhood diarrhea. Emerging Infectious Diseases. 12(2): 304-306.
Source: Parashar, UD, Hummelmann EG, Bresee, JS, Miller, MA, Glass, RI. Global illness and deaths caused by rotavirus disease in children. Emerging Infectious Diseases. Vol. 9, No. 5, May 2003
Top photo by Richard Lord.