Rotavirus has been in the news of late due to the sad loss of two lives, but there are also other causes of acute gastroenteritis. Find out what other bugs can cause upset tummies.
GASTROENTERITIS is due to irritation and inflammation of the gastrointestinal tract, which often results in diarrhoea, abdominal cramps, nausea, vomiting, and fever. This intestinal infection can be contagious, and can spread through contact with an infected person, unhygienic practices, and through contaminated objects, food or water.
Anyone can contract gastroenteritis. However, it is more common among infants and children under the age of five as they are more vulnerable to fluid and electrolyte losses.
As many of the organisms that cause gastroenteritis spread via the oral-faecal route, personal hygiene is very important to minimise the risk of spread of the illness.
Different causes
Gastroenteritis is caused by infection from different types of bacteria, viruses and parasites. These infectious agents can come from outside a person’s body, or result from an internal condition. Among the most common types of bacteria causing this infection are:
Escherichia coli (E. coli) – causes food poisoning, dysentery, traveler’s diarrhoea or colitis.
Salmonella – can cause typhoid fever or non-typhoidal food-poisoning.
Shigella – can cause dysentery (inflammation of the large intestine causing bloody diarrhoea).
Campylobacter – from undercooked meat and unpasteurised milk.
Viruses such as rotavirus, norovirus, and adenovirus account for 30-40% of gastroenteritis in children. They spread through close contact in daycares and schools.
Rotavirus is the most common and potentially lethal virus that primarily infects infants and young children, and it can be vaccinated against.
Each of these organisms causes a person to develop slightly different symptoms, but they all share one similarity – acute diarrhoea leading to dehydration.
Parasites and protozoa are less frequently responsible for intestinal irritation. However, they can infect you when you drink contaminated water.
Swimming pools are common places to come in contact with parasites, such as the Giardia parasite, as they are resistant to chlorine treatment.
Bouts of gastroenteritis can also be caused by food allergies, heavy metals, and certain medications.
The severity of a gastroenteritis infection depends on the immune system’s ability to resist the infection. Electrolytes (these include essential elements of sodium and potassium) may be lost as the affected individual vomits and experiences diarrhoea.
According to the World Health Organization (WHO), diarrhoeal disease is the second leading cause of death worldwide in children under the age of five, and is responsible for killing 1.8 million children every year.
Unlike bacterial infections, which are treatable with antibiotics, viral infections do not respond to antibiotics and add to the global statistics of child fatalities, especially in under-developed countries.
When will symptoms appear?
The incubation period for a gastrointestinal infection can differ depending on the type of germ causing it. For instance, the Shigella bacteria’s incubation period is typically two to four days, but the period for a viral infection ranges from four to 48 hours.
Parasitic infections generally have longer incubation periods, where symptoms can appear within one to four weeks.
Then, depending on the type of germ and the person’s overall health, a gastroenteritis infection can last for a few days or a few weeks.
Diarrhoea usually goes away on its own in a few days. Most people with acute gastroenteritis recover easily, especially healthy adults and teenagers.
But for small children and those with chronic illnesses, it can lead to dehydration that requires medical attention.
Know your viruses
As a parent, it is not so important to know which viruses are causing your child to run to the washroom every few hours. However, it is vital that he be assessed by a medically trained person on the degree of dehydration to start appropriate treatment. Knowing the virus will help to control and prevent the spread of this infection.
1. Rotavirus
Rotavirus, which resembles a wheel when looked under an electron microscope, is the most common, potentially lethal virus that primarily infects infants and young children. Symptoms such as fever, nausea, vomiting and watery diarrhoea will appear two days after exposure to this virus, and the symptoms may last up to eight days.
The virus spreads through the faecal-oral route or through contact with the stools (faeces) of an infected child. The germs from this virus have a long survival rate on infected surfaces such as toys or furniture.
Most children would have been infected by rotavirus by the age of five, and the first infection is usually the worst. However, once a child is exposed to this virus, subsequent exposure to it will have less severe effects as immunity against this virus develops.
Rotavirus vaccines have played a major role in preventing the spread of this virus in young children. The US Centers for Disease Control and Prevention (CDC) reports that while this viral disease is still a significant public health problem globally, there has been a clear reduction in hospitalisations and deaths of young children following the introduction of the vaccine.
Dehydration as a result of diarrhoea can be treated through oral rehydration. This means giving your child more fluids in the form of milk or oral rehydrating salt solutions to drink. Occasionally, intravenous rehydration may be required when the child is vomiting profusely.
Children who have been immunised and breastfed also stand a better chance against the rotavirus.
2. Norovirus
Formerly known as the Norwalk-like virus or NLV, norovirus belongs to a family of gastroenteritis-causing viruses. This virus spreads from person to person through contaminated food or water, and by touching contaminated surfaces. It can also occur if a person’s immune system is not strong enough to fight it.
Infection from this virus spreads in closed or crowded environments, such as hospitals, market places or nursing homes.
This viral infection occurs in all age groups, but is more common in adults.
Symptoms of diarrhoea, abdominal pains and vomiting begin to develop 24 to 48 hours after exposure and could last up to a few days.
Those who have previously been infected with norovirus can have the illness multiple times during their lifetime.
Similar to rotavirus and adenovirus, infection from norovirus is mild and does not require therapy, only treatment of its symptoms or complications. There is also no specific vaccine or drug to treat this infection.
3. Adenovirus
Adenovirus is mainly linked to respiratory illnesses; however it also causes gastroenteritis, conjunctivitis, and bladder infection. Symptoms from this viral infection range from the common cold to pneumonia and bronchitis.
Infants, young children and those with compromised immune systems are more susceptible to the effects of this infection.
Similar to the rotavirus, adenovirus is transmitted through the faecal-oral route, and direct contact with contaminated objects and water. Specifically, it is type 40 and 41 of the adenovirus that causes gastroenteritis, both in children and adults.
Infection from this virus is usually mild and does not require active therapy, only treatment of its symptoms or complications. There is also no specific vaccine or drug to treat this type of infection.
Preventing and controlling the spread
In order to reduce the chances of your child contracting gastroenteritis, always practise good hygiene. Hands must be well-washed after using the toilet, and before eating or touching food. Clean and disinfect contaminated surfaces after an episode of vomiting or diarrhoea. Wash all laundry thoroughly. Cook all foods carefully, and wash raw fruits and vegetables well before eating.
Also, avoid eating pink hamburgers or other undercooked meat, and always refrigerate leftovers quickly – nasty bacteria can grow after just a few hours of sitting on the counter.
The best prevention method is by vaccinating against the most common viral cause – rotavirus – even though it cannot prevent infection by the other organisms mentioned above.
Rotavirus vaccines are given orally to infants aged six months and less. The vaccines are very effective (85% to 98%) in preventing severe rotavirus disease in infants and young children. Rotavirus vaccines will not prevent diarrhoea or vomiting caused by other viruses, but they are very effective against rotavirus infection.
If your child has already contracted viral gastroenteritis, it is crucial to keep your child well-hydrated. A variety of oral rehydration solutions are available. Avoid giving your child fluids like water, apple juice or “isotonic” sports drinks. Water does not replace lost electrolytes, and apple juice could worsen the diarrhoea.
Also avoid sweet foods such as ice cream and candy as these can make diarrhoea worse. Continue to give milk, especially if it is breast milk. Seek immediate medical attention if your child cannot take fluids by mouth or in severe cases of dehydration.
Please remember that severe dehydration in infants can lead to death if not assessed and treated rapidly.
> Datuk Dr Zulkifli is a consultant paediatrician and & paediatric cardiologist. This article is courtesy of the Malaysian Paediatric Association’s Positive Parenting Programme under the Childhood Immunisation Campaign. The opinions expressed in the article are the view of the author. For further information, please visit www.mypositiveparenting.org.
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