Rotavirus: what kind of infection it is, symptoms, and why it is dangerous

In 2005, Nicaragua experienced the largest recorded rotavirus epidemic — an outbreak with an unusually wide reach and severe course, linked to mutations in the virus genome that may have allowed it to evade population immunity. By the age of five, virtually all children worldwide have had this infection. Below is a calm reference overview: what this virus is, how it is transmitted, and what its real danger is.

What rotavirus and rotavirus infection are

Rotaviruses are a genus of viruses in the family Reoviridae with double-stranded segmented RNA: the genome has 11 segments surrounded by a three-layered protein capsid with icosahedral symmetry. The particle diameter is 65–75 nm, and the appearance resembles a wheel with a wide hub and short spokes; hence the name — from the Latin rota, “wheel.” Rotavirus infection is often incorrectly called “stomach flu,” although the pathogen has no relation to influenza viruses. Rotavirus A accounts for more than 90% of human cases, and it also remains the most common cause of diarrhea in children.

How infection occurs

The main mechanism of transmission is fecal-oral: through contaminated hands, surfaces, and objects; airborne transmission is also possible through close contact with an infected person. The source is the feces of an infected person, which may contain more than 10 trillion viral particles per gram, whereas fewer than one hundred particles are enough to transmit the infection to another person. Outbreaks occur in preschool institutions, among hospitalized children, and in nursing homes. Seasonality is pronounced: in Russia, up to 93% of cases occur from November to April.

Main symptoms of rotavirus infection

The illness is cyclical: the incubation period lasts 1–5 days, the acute period 3–7 days, longer in severe cases, and recovery 4–7 days. The onset is acute: vomiting, a sharp rise in temperature, diarrhea, and the stool on the second or third day is often grayish-yellow and clay-like. Most patients develop a runny nose, redness in the throat, and pain when swallowing, lose appetite, and experience a decline in strength. Stool and urine may resemble a hepatitis picture: light-colored stool, dark urine, sometimes with flakes of blood. About two days pass from infection to the first symptoms, and vomiting and diarrhea may last from three to eight days.

Why rotavirus infection is dangerous: dehydration

The main threat is fluid loss (dehydration). Rotaviruses multiply mainly in the intestine, damaging enterocytes of the villi of the small intestine and causing their death; this leads to malabsorption, and the viral protein NSP4 impairs water reabsorption. Signs of dehydration are a warning signal: in children under five years, fewer wet diapers; in people over five, dark urine with a strong odor or less frequent urination. Some children receive care in a hospital.

How rotavirus is diagnosed

The key test is stool analysis, including detection of rotavirus antigen. The clinical picture is no less informative: a cyclical course with a combination of intestinal and respiratory syndromes at the onset of the illness, the characteristic appearance of the stool, and a seasonal rise help distinguish rotavirus from other causes of diarrhea. For comparison, common causes of diarrhea and vomiting include stomach infection and food poisoning. Making sense of this variety is the doctor’s task.

When to see a doctor

The acute period usually lasts 3–7 days, but there are situations that require examination by a specialist:

• signs of dehydration — dark urine with a strong odor or infrequent urination in a person over five years old;
• in a child under five years — fewer wet diapers than usual;
• the child stops feeding from the breast or bottle;
• diarrhea with blood or bleeding from the anus;
• diarrhea lasts more than seven days, vomiting more than two days.

Rotavirus infection by itself is not a reason to call an ambulance; 103/112 are needed if there is vomiting with blood or vomit that looks like coffee grounds, green vomiting in adults, yellow-green or green vomiting in children, neck stiffness and pain when looking at bright light, sudden severe headache, sudden severe abdominal pain, bluish, gray, or pale skin, lips, or tongue, severe difficulty breathing, or confusion.

If this concerns a child under 12 months and something worries you, do not delay talking to a doctor. This material is for reference and does not replace consultation with a doctor: only a specialist can assess the condition of a specific person.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer