Rotavirus enteritis primarily occurs in infants and young children, often caused by Group A rotavirus, with the peak incidence in autumn, hence the name "infant autumn diarrhea." Group B rotavirus can cause diarrhea in adults and was first reported in China.

bubble_chart Epidemiology

It primarily causes diarrhea in infants and young children during autumn, which can extend into winter, and occurs worldwide. There have also been outbreaks among adults. In addition to fecal-oral transmission, it has been confirmed that the virus can spread through respiratory air, with specific antibodies detected in respiratory secretions. Newborns and young infants are protected by maternal antibodies, resulting in fewer cases compared to the 6-month to 2-year age group.

bubble_chart Pathogen

Rotavirus was first discovered in 1973 by Bishop from the epithelial cells of intestinal biopsies of children with diarrhea in Australia, and was named "rotavirus" due to its wheel-like shape. The virus particles contain double-stranded RNA, with a diameter of 70nm, and there are also defective viruses with a diameter of 55nm. Electrophoresis typing divides them into 7 groups, namely A to G groups, and recently, pararotavirus has been discovered. The first to be discovered was group A, group B rotavirus was found in China, and group C was first discovered in Japan in 1988. Groups A, B, and G can cause zoonotic diseases, while the other groups mainly cause animal diarrhea, with a few infecting humans.

bubble_chart Pathogenesis

The virus invades the epithelial cells of the small intestine, causing the villi to shorten and shed, leading to the loss of small intestine function. The activity of mucosal disaccharidases decreases, resulting in impaired hydrolysis and absorption of xylose and sucrose in the intestinal lumen, which are then decomposed by bacteria to produce organic acids. This increases the osmotic pressure in the intestine, causing a large amount of water and electrolytes to enter the intestinal lumen and reducing intestinal absorption.

The incubation period is approximately 2 to 3 days, with most symptoms being mild, but a few infants may experience severe or even fatal manifestations. The main symptoms include watery diarrhea, with bowel movements occurring 10 to 20 times a day, accompanied by vomiting. Some may also have fever, abdominal distension, and fullness. About half of the affected children experience mild to grade II dehydration, possibly accompanied by electrolyte imbalances. The course of the illness generally lasts 5 to 7 days, but it can extend beyond 10 days. In immunocompromised children, chronic rotavirus enteritis may develop, with long-term viral shedding in feces, becoming a source of pestilence.

Adult rotavirus enteritis is generally milder, but severe diarrhea can occur in elderly individuals with a compromised philtrum.

bubble_chart Auxiliary Examination

The stool is watery, occasionally with a few white blood cells, and no blood. Special wheel-shaped viruses are easily seen under electron microscopy of the stool. ELISA kits have been used to measure viral antigens in the stool, with accuracy comparable to electron microscopy. Latex agglutination and PCR methods are also used to detect stool antigens, and antigens can be measured on diapers with stool or rectal swabs. If stool collection cannot be tested immediately, it should be stored at -70°C for future testing.

Specific serum IgM antibodies can be detected 5 days after infection, and IgG antibodies appear 2-4 weeks later. Specific IgA can be detected in pharyngeal secretions.

bubble_chart Diagnosis

The diagnosis primarily relies on clinical manifestations, stool electron microscopy, or antigen testing. The seasonality of the disease in infants and young children holds significant reference value.

The disease is mainly treated with symptomatic and supportive therapy. Grade I dehydration is treated with oral rehydration, while moderate and Grade III dehydration accompanied by electrolyte disturbances is treated with intravenous rehydration. According to the World Health Organization, each liter of oral rehydration solution contains 20g of glucose, 3.5g of sodium chloride, 2.5g of sodium bicarbonate, and 1.5g of potassium chloride.

In recent years, oral rotavirus antibodies have been used for treatment, which can alleviate symptoms and promote recovery in a few immunocompromised patients with chronic rotavirus enteritis. However, no effect has been observed in normal children and infants after oral administration.

bubble_chart Prevention

Two types of vaccines are widely used in clinical practice. One is the bovine rotavirus NCDV strain, known as RIT4237; the other is the African green monkey rotavirus strain RRV-1, known as MMY-18006, which is attenuated through cultivation to produce an oral vaccine. This vaccine has shown some effectiveness, and it has been observed that breastfeeding does not interfere with the efficacy of the oral vaccine. However, the level of protection may be related to the serotype. Japan has proposed that the vaccine must contain four serotypes of group A rotavirus to provide immunity against group A rotavirus infections.

Breast milk contains specific rotavirus IgA, and breastfed infants are less likely to develop or do not develop rotavirus gastroenteritis, which is why breastfeeding is encouraged.