Noroviruses are a group of viruses that cause gastroenteritis (i.e. inflammation of the stomach or intestines), which leads to cramping, nausea, vomiting, and diarrhea.

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Intestinal infections tend to hit at the worst times. Five years ago, my husband, two children and I were cruising from one Croatian Island to the next when it happened—gut-wrenching cramps doubled me over while sweat dripped down every crevice. I had gone from feeling slightly nauseous to wanting to die within minutes—all because of an intestinal infection I developed from eating bad tuna 12 hours before.

Whether they’re caused by a food-borne illness, like mine was, a parasite, or bacteria you picked up from your kids, intestinal infections are nasty. They trigger inflammation of the gastrointestinal tract (i.e. the stomach and the small intestine). Their most worrying side effect: dehydration. From recognizing the clues necessary to diagnose your illness to learning how to treat and prevent one from taking over, here’s what you need to know about intestinal infections.

What Are the Most Common Signs and Symptoms of Gastrointestinal Disorders?

The number one sign that you’ve contracted an intestinal infection? Diarrhea. “Most GI infections are caused by viruses, which manifest as a short-lived, watery diarrhea,” says Dr. Daniel Freedberg, MD, MS, Assistant Professor of Medicine at Columbia University Medical Center. “Dysentery (bloody diarrhea) is more likely to be caused by bacteria.” Other symptoms include nausea, vomiting, cramps, and sometimes fever.

How Long Does It Take to Get Over an Intestinal Infection?

It depends on what type of intestinal infection you’re suffering from. While certain conditions, such as a food-borne illness, can be beaten within 24 hours, others, like certain parasites, can take months to get over.

What Antibiotics Treat Intestinal Infection?

In some cases, time and plenty of fluids are the only treatment for an intestinal infection. For others, such as bacterial infections or parasites, antibiotics may be in order. The most commonly prescribed medicines to treat intestinal infections include fluoroquinolones and metrindazole, azithromycin, and trimethorprim-sulfamethoxazole, says Freedberg. “But this depends entirely on the organism, and a variety of medicines are used, including anti-parasitics.”

Common Types of Intestinal Infections

There are three main types of intestinal infections.

1. Norovirus. This group of viruses cause gastroenteritis (i.e. inflammation of the stomach or intestines), which leads to cramping, nausea, vomiting, and diarrhea. According to the Centers for Disease Control (CDC), norovirus causes between 19 and 21 million illnesses each year. They estimate “that a person will get norovirus about 5 times during their lifetime.” If you’ve ever had this type of intestinal infection, you know that one time is too many! Norovirus can also cause food-borne illness if the germs were transferred to a piece of food. It’s highly contagious, with over 80 percent of outbreaks occurring during the winter (i.e. from November to April).
2. Food-borne bacterial infections. According to the CDC, 48 million people get sick every year from a food-borne illness. They also claim that over 250 of these diseases have been identified. “Most of them are infections, caused by a variety of bacteria, viruses and parasites,” says the CDC.One of the most prevalent types of food-borne diseases, Clostridium perfringens causes close to one million cases of food poisoning each year. Commonly found on raw meat and poultry, this bacterium can rapidly multiply and create a toxin in the intestine. It’s often contracted from “beef, poultry, gravies, and dried or pre-cooked foods,” says the CDC. The good news: symptoms come on quickly and last for less than 24 hours. Plus, you’re not likely to vomit or get a fever, and it’s not contagious. Our old friend Salmonella is another food-borne illness that can lead to an intestinal infection. According to the CDC, Salmonella causes about 1.1 million illnesses in the U.S. each year. The symptoms include, diarrhea, fever, and abdominal cramping, which appear between 12 and 72 hours after becoming infected. It takes between 4 to 7 days to recover. Shigella and E. coli are two other types of bacteria that can cause an intestinal infection. As is the case with Clostridium perfingens and salmonella, they are often contracted by consuming undercooked food (i.e. poultry, beef, milk products or eggs). They can also be transferred after having close contact with a contaminated animal or its water.
3. Intestinal parasites. Another frequent cause of intestinal infection, these are confused often for food poisoning. According to the CDC, “Giardiasis is the most frequently diagnosed intestinal parasitic disease in the United States and among travelers with chronic diarrhea.” It can last for one to two weeks or longer and includes symptoms such as gas, greasy stool that floats, abdominal cramps, nausea, vomiting, and diarrhea. These crop up seven to 10 days following exposure. Giardiasis is often found in water (i.e. a swimming pool or lake) and is contracted after being ingested. Cryptosporidium is another common parasite that is commonly spread the same way.

What to Eat (And Avoid) When You Have an Intestinal Infection

Your first line of defense when you’re suffering from an intestinal infection: drink plenty of fluids to avoid dehydration. Then, slowly try a bland diet known as BRAT (bananas, rice, applesauce, and toast), recommends Freedberg. Steer clear of milk products, though, since most types of illnesses that cause infectious diarrhea cause lactose malabsorption.  “The exact foods eaten are probably not critical,” he says, “but alcohol, milk products, very fatty foods, and foods which may contribute towards diarrhea should be avoided.”

Is an Intestinal Infection Contagious?

It depends on the type. As mentioned earlier, certain infections, such as norovirus, are highly contagious. Others, such as food-borne illnesses, are easily transferrable from infected foods, but aren’t likely to be passed from one person to another (unless you’ve managed to rub raw chicken on your friend’s hands or mouth, for instance). That said, Freedberg says, “most GI infections are contagious, transmitted by accidental ingestion of fecal material. However, exposure to a potential pathogen is not synonymous with infection.” In other words, whether you’ll contract an intestinal infection depends on how many of the infected organisms you ingest (gross!) as well as how healthy you were when you ingested them.

How to Prevent an Intestinal Infection

The best way to avoid getting sick: wash your hands! Also, carefully rinse fruits and vegetables, and cook poultry, meat, oysters and other shellfish thoroughly. Keep food at the correct temperature once cooked (140°F or warmer or 40°F or cooler) to prevent growth of bacterial spores that may have survived the cooking process. Refrigerate food at 40°F or colder within two hours of preparation and reheat to at least 165°F.

Also, clean and disinfect contaminated surfaces (e.g. toilets, countertops, TV remotes and door handles). One more thing: Remove and wash clothing or sheets immediately after they’ve been contaminated.

Intestinal Infection: Home Remedies

“Oral rehydration is the most important home remedy by far,” says Dr. Freedberg. Boost the electrolytes you’ve lost through diarrhea and vomiting by adding a tablespoon of sugar and half a teaspoon of salt to one liter of water. Then, drink up. “When people are dying of infectious diarrhea (usually in the developing world), this recipe saves lives,” he says.=

How Common are Intestinal Infections?

Very, says Dr. Freedberg. “A healthy person can expect to have a—usually mild, usually viral—enteric infection every several years.” Great, something to look forward to!

For related reading, visit these posts:

• Stomach Flu or Food Poisoning? How to Tell the Difference
• Could Dehydration Be the Answer to Your Question, “Why Do I Feel Tired All the Time?”
• 8 Diverticulitis Symptoms You Should Watch Out For
• Gastroenteritis: What You Can Do to Protect Yourself
• SIBO Diet: What to Eat If You Have Small Intestinal Bacterial Overgrowth
• Probiotics and Antibiotics Should Go Together Like Cheese and Wine
• Gastritis Definition: What Is Gastritis, and Why Is the Term So Confusing?
• SIBO Treatment with Herbs Is as Effective as Antibiotics
• Foods That Stop Diarrhea
• What Causes Diarrhea?
• Natural Cures for Nausea and Dehydration
  
• One of the Best Natural Remedies for Food Poisoning: Oregano Oil

This article was originally published in 2018. It is regularly updated.