Viral gastroenteritis
Gastroenteritis is the inflammation of the stomach, small intestine, or large intestine, leading to symptoms such as vomiting and diarrhea. Several viruses can cause viral gastroenteritis, with the most common being rotavirus, norovirus, and adenovirus. In Taiwan, the primary epidemic season for norovirus and rotavirus occurs from November to March of the following year, while adenovirus infections can happen year-round. Rotavirus, adenovirus, sapovirus, and astrovirus are particularly prevalent in children under five years of age, with rotavirus being the leading cause of diarrhea in infants and children under 5 years of age. Norovirus, on the other hand, can be infected at any age. Norovirus outbreaks are more common in densely populated settings, such as schools, hospitals, military barracks, and shelters. They can also occur in venues like restaurants, large cruise ships, dormitories, and campgrounds.
Pathogens
A variety of viruses can cause gastroenteritis, including Norovirus, Rotavirus, Adenovirus 40/41, Sapovirus, and Astrovirus.
Epidemiology
- Distribution of Norovirus:
- (1)Widely distributed around the world, Japan, the United States, Europe and other countries have had epidemics of varying scales in recent years.
- (2) The CDC estimates that about 19 million to 21 million people are infected with Norovirus each year, leading to cases of acute gastroenteritis, with 50% of these infections being foodborne. Between 2009 and 2012, there were 3,494 reported gatherings associated with Norovirus outbreaks, including those in medical institutions (62.7%), restaurants or banquet halls (22.1%), and schools or daycare facilities (6.1%).
- (3) Norovirus is also prevalent in densely populated institutions such as schools, hospitals, military camps, shelters, and nursing homes in China. Additionally, it frequently occurs in restaurants, large cruise ships, dormitories, and campsites.
- Distribution of Rotavirus: Rotavirus is the leading cause of acute gastroenteritis in infants and young children, with nearly every child under the age of 5 having been infected at some point. Globally, it is estimated that 450,000 children under 5 years old die each year due to rotavirus infection, with over 90% of these deaths occurring in developing countries.
Reservoir
- Norovirus, humans are the only carriers of the virus.
- In addition to infecting humans, rotavirus can also infect cattle and primates, but unlike others, rotavirus in animals does not infect humans.
Mode of transmission
Viral gastroenteritis is primarily transmitted through the fecal-oral route. This can occur by consuming food or water contaminated with the virus, or through close contact with infected individuals, such as sharing food, water, or utensils. Infection may also result from contact with vomit, feces, or surfaces that have been contaminated by an infected person. Additionally, inhaling droplets from vomit or feces can lead to transmission.
Clinical symptoms
The main symptoms of viral gastroenteritis are diarrhea and vomiting, and there may also be headache, fever, abdominal cramps, stomach pain, nausea, muscle aches and other symptoms, usually 1~3 days after infection, gastroenteritis symptoms begin to appear, symptoms can last 1~10 days, the length of the disease depends on the type of virus infected and the individual's immunity. Most people who get viral gastroenteritis usually recover completely without long-term sequelae, but for people who lose fluids and electrolytes due to vomiting or diarrhea and cannot replenish them, such as infants, young children, the elderly, immunocompromised and those who need long-term care, the loss of fluids may lead to dehydration and electrolyte imbalance, followed by convulsions, and even death.
Prevention
- Pay attention to personal hygiene and wash your hands properly with soap or hand soap before preparing meals, before eating, after going to the toilet and after caring for the sick (including changing diapers or handling excreta for infants or the elderly).
- Vegetables and fruits should be cleaned and raw food and drinking should be avoided, especially shellfish and aquatic products should be cooked thoroughly before eating; When eating with others, use a serving chopsticks or serving spoon.
- To prevent the spread of the disease, contaminated clothing and bed linens should be changed immediately, and the environment or surfaces should be disinfected with bleach.
- Breastfeeding can improve the immunity of infants.
- Wear a mask when entering and exiting public places, as well as when cleaning and disinfecting excreta or vomit of patients to avoid droplet infection.
Communicable period
Norovirus is usually contagious for 48 hours after the acute diarrhoea has stopped.
Rotavirus is usually infectious within 8 days of an acute attack.
Incubation period
Norovirus usually lasts between 24 and 48 hours.
Rotavirus generally lasts 24 to 72 hours.
資料來源：Taiwan Centers for Disease Control http://at.cdc.tw/f3vwW5