The causes and symptoms of viral gastro-intestinal disease

Viral gastrointestinal infections can be caused by enteric viruses such as rotaviruses, adenoviruses, norovirus and astroviruses. Majority of the infections usually occur in children as seen in Rotavirus but viral infections also occur in adults. These enteric viruses mainly cause diarrhoea and vomiting but in other instances abdominal and muscle pains, fever and nausea as seen in table 1 below. Most of these infections are usually mild, acute, self-limiting and does not last long. They are usually transmitted from person to person and in some cases through the inhalation of airborne droplets produced during explosive vomiting.

The methods available for the detection of gastrointestinal viral pathogens from faecal samples include manual and automated. Automated analysers include Dynex DS2 and Biomerieux Vidas. Other methods include Enzyme Linked Immunosorbent Assay (ELISA), Polymerase Chain Reaction (PCR), Viral culture and Electron microscopy.

Oral rehydration solution (combination of water, sugar and salt) is used in mild and moderate cases of viral gastrointestinal infections for the replacement of lost bodily fluids. However, intravenous route can be use in more severe cases. Antibiotics should not be used.

Table 1: Properties and symptoms of enteric viruses that causes viral gastrointestinal diseases.

Enteric viruses causing gastrointestinal infections	Viral genome	Age group	Incubation period	Duration of infection/ symptoms	Symptoms
Rotavirus	Double stranded RNA	Usually <2 years old.	1 – 3 days	3 – 7 days	Vomiting, diarrhoea, fever and abdominal pain.
Adenoviruses	Double stranded DNA	Usually <2 years old.	2 – 10 days	5 – 12 days	Vomiting and diarrhoea
Norovirus	Single stranded RNA	All age groups.	10 – 48 hours	24 – 48 hours	Vomiting, diarrhoea,fever, nausea, headache and abdominal pain.
Astroviruses	Single stranded RNA	Infants and young children.	3 – 4 days	2 – 7 days	Vomitting and diarrhoea