Food poisoning or stomach bug?
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You've been up all night with stomach cramps, diarrhoea and vomiting. You feel rotten and you can't keep anything down. Everyone's got a theory as to what's going on and you no doubt wonder yourself…
Was it something you ate? Or have you been struck with the latest horrible tummy virus?
It's true that gastroenteritis – an inflammation of the gut usually caused by an infection – can be caused either by something you ate or a viral infection passed from another person, says Dr Jas Saini, a GP in the western suburbs of Sydney.
Both scenarios can result in similar symptoms such as fever, stomach cramps, diarrhoea and vomiting. But there are often clues that suggest which problem you're dealing with, Saini says.
Typically (but not always) food poisoning starts more dramatically with sudden onset of severe symptoms. But viral gastroenteritis can also cause quite severe abdominal pain, and it can make people just as miserable, Saini says.
"It's not always easy to work out the difference and your doctor will ask a series of questions to try to work out the cause."
Viral gastro
Viral gastroenteritis, caused by bugs like rotavirus and norovirus, tends to peak in winter and spring. It is spread by you coming into contact with surfaces that have been contaminated with human faeces. Symptoms may come on gradually.
"Surfaces can become contaminated if you have not washed your hands properly after using the toilet, or got some stool on your hands when wiping and not washed it off properly. You can then pass the virus on when you touch the tap, toilet flush, door handle or other surfaces."
"Viruses can be present on surfaces anywhere, including escalators and traffic lights and they can stay around for a period of time."
Viral gastro can also be spread through food if people don't wash their hands properly before preparing food. And you can still spread the virus for up to 48 hours after your symptoms have disappeared completely too, Saini says.
That's why it's important to wash hands properly after using the toilet and before eating food.
Food poisoning
On the other hand, food poisoning usually refers to gastro related to eating food that is contaminated with bacteria such as Salmonella, Campylobacter or E.coli.
"Whilst exposure to the culprit food may occur hours or weeks before you fall crook, the symptoms of food poisoning tend to be more dramatic and build up much more quickly than those of viral gastroenteritis."
"You may experience intense vomiting, high fevers and severe abdominal pain. Severe dry retching may also occur, and people describe the feeling of their gut vigorously squeezing out its toxins. It's also more common to see blood or mucous in your stool with food poisoning," Saini says.
"If you do notice blood or mucous, then it's important to go to the doctor to get checked out."
"Stool samples are taken if the doctor is uncertain about the diagnosis, there is blood or mucous in the stool, a bacterial infection is suspected, or symptoms have gone on for a long time. Your doctor may also consider stool samples if you have recently returned from overseas, or if she or he feels your immune system is compromised"
"Antibiotics may be considered for bacterial infection, although many people can get better without using antibiotics," Saini says.
Nailing the culprit
If you think you may have food poisoning, particularly from food you have eaten out, tell your doctor, so they can report it to the public health department who can investigate the source of the problem, Saini says.
But knowing the source of your food poisoning can be tricky. It's not always the last thing you ate that made you sick – it could be anything you have eaten days, weeks or, in the case of listeria bacteria, even months before.
And what you bring up is not necessarily the cause of your illness – it's just what was in your stomach when the symptoms started.
But if your whole family all ate the same dish at your local restaurant and all suddenly got violently ill together shortly afterwards, that's a pattern more suggestive of food poisoning.
Preventing the spread
For viral gastro, preventing its spread through families is actually very difficult.
"There's always a bit of guilt," Saini says. "You can be very careful with hygiene and cleaning surfaces but it's very easy for the whole family to affected all at once."
What's more the common gastro virus norovirus can travel in air droplets, causing much wider contamination of surfaces, says virus expert Professor Bill Rawlinson. Norovirus can also reach the gut by being inhaled into the back of the throat.
"We think it's not a classic aerosol spread like you see with respiratory viruses," says Rawlinson, director of virology at South Eastern Sydney and Illawarra Health Service. You probably need to be in quite close proximity "like a parent cleaning up a child's diarrhoea or vomit". Wearing a mask may be helpful in these circumstances, he says.
To prevent gastro from any cause, it's important to:
- Practice good hand hygiene including always washing your hands with soap and hot water before preparing food, after handling raw food, before eating, after using the bathroom or changing nappies, after working in the garden, or after playing with or feeding pets.
- Store and handle your food safely such as separating raw and ready-to-eat foods, keeping hot food hot (over 60°C) and cold food cold (under 5°C), cooking and reheating foods thoroughly, refrigerating food within two hours of cooking, and thoroughly washing fruit and vegetables.
When to go to the doctor?
'Gastro' can be life threatening in vulnerable people such as babies, pregnant women and elderly people. "That's because they have limited reserves and require more fluids," Saini says.
He recommends going to the doctor if you have:
- vomiting without diarrhoea – this may not be a gastro bug at all and could be another problem such as an ear infection or a urinary tract infection.
- severe stomach pains that are getting worse quickly or came on very suddenly
- blood or mucous in your stool, or stools that are black or very smelly. Black stools may indicate there is bleeding higher up in the gut.
- difficulty passing urine or only passing small amounts of urine
- symptoms that last for more than a few days
- other medical conditions that require careful monitoring, such as diabetes
Take babies to the doctor if they are not tolerating their feeds, they are pale and lethargic or have fewer than four wet nappies in 24 hours.