1. Gastroenteritis (infectious diarrhea)

Causes of bacterial gastroenteritis:
Salmonella, Staphylococcus aureus, Shigella, etc.

Causes of viral gastroenteritis:Rotavirus, Norovirus, Sapoviruses, Astrovirus, Adenovirus type 40 and 41, etc.
There are two small, round-structured viruses—Sapporo-like viruses and Norwalk-like virus, which have been renamed and classified into Sapovirus and Norovirus, respectively.

Epidemiology

1. (1) Rotavirus:

   US Centers for Disease Control and Prevention (CDC) revealed that rotavirus infection mostly occurs in children under age-five in developed countries.

2. Norovirus:

   1. Common in Japan, America, and Europe.
   2. The annual number of norovirus infection is estimated at 23 million, 50% of norovirus infection is implicated in contaminated food. Suspected mode of transmission of outbreaks are: person-to-person, foodborne, and waterborne.
   3. In Taiwan, norovirus infection often occurs in densely populated institutions, e.g. daycare centers, kindergartens, schools, long-term care institutions.

3. Sapovirus:

   Both sapovirus and norovirus are viruses belonging to the Caliciviridae family, with single-stranded positive-sense RNA. Sapovirus particles are typically 41–46 nm in diameter. Low concentration of sapovirus in fecal samples makes it difficult in the detection of sapovirus. Sapovirus outbreaks often occur in daycare centers and kindergartens.

 

Host

1. Rotaviruses infect humans and other species of animals, e.g. young calves and primates.
2. Humans serve as the natural host of noroviruses.
3. Sapoviruses are known to infect humans. Sapoviruses also infect swine. Sapoviruses of swine origin belong to genogroup GIII.

 

Transmission

In viral gastroenteritis, viruses are mainly transmitted by the fecal-oral route, via contact with contaminated foods, water, hands, surfaces and objects. Vomiting transmits infection effectively.

Peak season

• Rotavirus

  autumn, winter.

• Norovirus

  throughout the year, prevalent in cold weather, e.g. autumn, winter, early spring.

• Sapovirus

  late spring, early summer.

 

Incubation period

• Rotavirus: 1-3 days
• Norovirus: 1-2 days
• Sapovirus: 5-12 days

 

Contagious period

• Rotavirus: up to eight days after symptoms and signs are first apparent.
• Norovirus: 48 hours after recovery from diarrhea
• Sapovirus: 1-2 days before symptoms and signs are first apparent, up to 14 days after symptoms and signs are first apparent.

 

Susceptible groups

Infants, disabled, elders, nursing institutes, schools, medical centers, hospitals, banquets, cruises, dorms, camps and crowded places.

Symptoms

Nausea, vomit, diarrhea, abdominal pain, fever, stomach cramps. Typically, these symptoms last for 1-6 days.

Treatment

Treatment of acute viral diarrhea is nonspecific and involves management of symptoms.

Prevention

Frequent hand-washing. Avoid unboiled water and raw food. Keep good personal hygiene habits. Inform health authorities if collective diarrhea occurs.

What to do if Your child has diarrhea

Consult doctor. Major causes of diarrhea in summer are bacteria. Antibiotics are effective in the treatment of bacterial diarrhea. Use antibiotics based on advice. When it comes to viral diarrhea, there is no specific medicine. Management of dehydration is vital. The child could be given extra water to drink that contains small amounts of salt and sugar. During diarrhea, disruption of gut flora often occurs. Restoration of normal gut flora and intestinal barrier can be achieved by: consumption of probiotic supplements (e.g. patented probiotics with antiviral effect).

L-glutamine is helpful in reducing diarrhea symptoms by providing protection of gut mucosa.