Viral Diarrhea

What is Viral Diarrhea?

Viruses are the main cause of sudden, infectious stomach and intestinal inflammation, or gastroenteritis, in the United States and across the world. In fact, they are often the reason behind most instances of sudden diarrhea that someone catches in their community. Sudden or acute diarrhea is when you start passing watery or loose stools more than three times within 24 hours, or at least 200 grams of stool per day. This condition usually lasts for up to 14 days.

It’s also possible to have other symptoms like feeling nauseous, throwing up, running a fever, experiencing abdominal (stomach area) pain, and general discomfort. Some people may also have respiratory (breathing) symptoms, feel tired, and lose weight.

What Causes Viral Diarrhea?

Several viruses, like rotavirus, enteric adenovirus, astrovirus, and the Norovirus and Sapovirus (which belong to the Caliciviridae family), have been extensively researched as common causes of illnesses in humans. Certain types, like aichivirus, that are part of the Picornaviridae family, are thought to cause stomach and intestinal inflammation. However, there are still other viruses that cause diarrhea whose origins haven’t been found yet.

The Norovirus, another member of the Caliciviridae family, is a common cause of sudden stomach and intestinal inflammation. It is a tiny virus without an envelope around it that has one strand of RNA. This virus may cause significant outbreaks often through contaminated water or food and can easily spread from person to person.

Outbreaks of viruses can also happen in places with lots of people, like schools, or on cruise ships. The rotavirus, a member of the Reoviridae family, is a virus without an envelope with two strands of RNA. There is also the enteric adenovirus, a virus without an envelope that has two strands of DNA. Types 40 and 41 of this virus are the main ones that cause stomach and intestinal inflammation, especially in children younger than 2.

Risk Factors and Frequency for Viral Diarrhea

Rotavirus, Norovirus, and Adenoviruses are common viruses that cause gastroenteritis, an inflammation of the stomach and intestines.

• Rotavirus often spreads among individuals in winter and spring. Before vaccines were available, this virus caused 30% to 70% of child hospital admissions due to sudden (acute) gastroenteritis. Globally, rotavirus results in around 800,000 cases of acute gastrointestinal sickness in children yearly. Adults can also get infected, but their symptoms are usually less severe.
• Norovirus is the leading cause of diarrhea obtained outside of a healthcare setting. This virus leads to outbreaks of gastroenteritis and foodborne illnesses both in the United States and around the world. Each year in the United States, Norovirus is responsible for about 800 deaths, 71,000 hospitalizations, 400,000 emergency department visits, 1.9 million scheduled doctor visits, and 21 million instances of disease.
• Adenovirus types 40 and 41 typically cause gastroenteritis in children under two, especially in daycare settings. However, Adenoviruses are generally less infectious than Rotavirus and Norovirus, leading to fewer medical consequences.
• Every year in the United States, diarrheal illnesses lead to around 179 million outpatient visits, 500,000 hospitalizations, and over 5,000 deaths.

Signs and Symptoms of Viral Diarrhea

Acute viral gastroenteritis often shows up 24 to 60 hours after exposure and typically lasts from 12 to 60 hours. Vomiting is a common symptom, while the length of diarrhea can differ depending on the type of virus causing the illness. Fever, though not always present, can also accompany these symptoms. The severity of these symptoms can vary widely, from mild discomfort to severe dehydration, although severe cases are relatively rare.

There are different types of viruses that can cause acute gastroenteritis and their symptoms can vary slightly. For example, rotavirus often begins with vomiting, followed by intense diarrhea, and sometimes fever. This illness usually lasts between 5 and 7 days. Norovirus, on the other hand, is more variable. While vomiting, diarrhea, and nausea are common symptoms, some children may experience only vomiting, and some older adults may experience only diarrhea. Symptoms often show up 12 to 48 hours after exposure and commonly last 1 to 3 days. Enteric adenovirus is different in that it has an incubation period of 8 to 10 days and the illness can last for up to 2 weeks.

• Rotavirus symptoms: Vomiting, intense diarrhea, potential fever, lasting around 5-7 days
• Norovirus symptoms: Vomiting, diarrhea, nausea, lasting approximately 1-3 days
• Enteric adenovirus symptoms: Vomiting, diarrhea, with an illness duration of up to 2 weeks

During a physical examination, patients may feel mild, all-over abdominal pain. Even though doctors may see some reflex stomach muscle tightening, the abdomen often remains soft to the touch. Around half of all patients may have a mildly high fever between 101°F and 102°F.

Testing for Viral Diarrhea

For those experiencing acute diarrhea, it’s essential to figure out the cause, whether it’s an infection or something else. Usually, viruses causing acute stomach illness are diagnosed through a clinical evaluation, which means you talk about your symptoms with your doctor instead of conducting laboratory tests or stool studies. Stool studies, which check your poop for illness indicators, are generally not needed unless you have continued fever and dehydration, or there’s blood or pus in your stool.

Your doctor can usually tell if you’re dehydrated by looking at you, so blood tests for dehydration, like serum electrolytes, are not often needed. Blood count tests aren’t the most reliable way to tell if your diarrhea is caused by a virus or a bacteria. If a lab test is required, the most common technique is reverse transcriptase-polymerase chain reaction (RT-PCR) of stool. This test looks for unique evidence of a virus’s genetic material in your poop.

There are quick diagnostic tests available to detect specific viruses in your stool, such as rotavirus and adenoviruses. These tests use techniques like an enzyme immunoassay (EIA), latex agglutination, or nucleic acid amplification techniques (NAATs).

Diagnosing a Norovirus infection can be difficult because there are many different types of this virus. There are certain criteria called the Kaplan criteria that doctors use to identify Norovirus outbreaks, such as short incubation time (time from when you get infected to when you start showing symptoms), short illness duration, and the presence of vomiting with more than 50% of affected people showing a negative stool culture. These criteria are right 98% of the time (high sensitivity) but might point to Norovirus when it’s actually something else about 32% of the time (68% specificity).

Doctors can identify Noroviruses using the RT-PCR technique or EIAs to detect certain viral proteins. However, there currently isn’t a universal test approved by the U.S. Food and Drug Administration (FDA) to diagnose a Norovirus infection.

Treatment Options for Viral Diarrhea

Viral diarrhea is a short-term condition that normally improves on its own, so medicines aren’t usually needed. Most people can recover at home by drinking enough fluids. However, you might need to go to the hospital if you have severe dehydration, frequent or greenish vomiting, can’t keep down fluids, have kidney abnormalities, experience changes in your thinking or behaviour, or have intense stomach pain.

The elderly, those who have lost weight, people with weak immune systems, pregnant women, and those who have been in the hospital recently or have used antibiotics in the past few months might also need hospital care. This is because they might have a higher risk of a specific type of infection called Clostridioides difficile.

The main issues with viral gastroenteritis, also known as stomach flu, are losing fluids and electrolytes. For adults without severe dehydration, sports drinks and broths can help replace these losses. Oral rehydration solutions, which can be bought at the pharmacy, are better than sports drinks for those with mild to moderate dehydration. People who are severely dehydrated or can’t drink enough fluids might need to get fluids through an IV in the hospital. There aren’t any strict dietary restrictions, but eating smaller meals and choosing mild, easy-to-digest foods might help.

Medicines to stop vomiting or diarrhea are sometimes required, but they aren’t usually recommended because they can have side effects. Probiotics and prebiotics, which are types of dietary supplements, aren’t typically recommended either.

Zinc supplements aren’t recommended for adults with acute diarrhea since their benefits aren’t well-studied. However, the World Health Organization recommends zinc for children with acute diarrhea because diarrhea can lead to a zinc deficiency, which can make the symptoms last longer and be more severe.

There are also two types of rotavirus vaccines, which protect against a common cause of viral diarrhea. They’re given to infants at 2 months of age.

What else can Viral Diarrhea be?

When diagnosing acute viral gastroenteritis, which is a stomach infection, doctors need to consider other reasons for the illness. These can include other types of infections—like viral, bacterial, or parasitic—or non-infection related reasons that can cause sudden diarrhea. If a patient has had diarrhea for more than a week, doctors should get a detailed health history. Important information includes any recent travel, hikes, or any specific sexual behaviors. If the history points to a possible cause, doctors should test for parasites like Cryptosporidium or Giardia. If the patient has recently been hospitalized or used antibiotics, it’s essential to explore the chance of a C. difficile infection.

Doctors also consider foodborne illnesses that are mostly due to bacterial infections when symptoms appear within a shorter time (usually 8 to 16 hours) after eating the food, which is quicker than most viral infections develop. There are also non-infectious factors that might cause diarrhea and need to be looked at. They include things like:

• Colorectal cancer
• Irritable bowel syndrome
• Inflammatory bowel disease
• Colitis
• Issues with digestion
• Diarrhea after gallbladder removal
• Medications

What to expect with Viral Diarrhea

Acute viral gastroenteritis, commonly known as stomach flu, typically comes and goes on its own and the outcome is usually good. However, severe dehydration caused by this condition may require a hospital stay, especially for very young and older individuals. If the symptoms of stomach flu don’t get better, it might become necessary to have more regular check-ups or even to be hospitalized.

People with other existing health conditions may be more likely to experience complications and face worse outcomes if they get stomach flu. They might need to be admitted to the hospital if their symptoms don’t improve. These health conditions could include:

• Autoimmune diseases, like rheumatoid arthritis and systemic lupus erythematosus — these conditions cause your immune system to attack healthy cells in your body
• Cancer
• Conditions that require immunosuppressant drugs, systemic corticosteroids, or diuretics — drugs that reduce inflammation, control the immune response, or help the body get rid of excess water
• Hematopoietic cell transplant — a procedure where healthy blood stem cells are given to replace unhealthy ones
• Immunodeficiency syndromes like T-cell immunodeficiency or severe combined immunodeficiency — these are conditions where the immune system is not working properly
• Inflammatory bowel disease — a group of disorders causing inflammation in the digestive tract
• Metabolic diseases, like diabetes mellitus — conditions that affect how the body turns food into energy
• Renal impairment — issues with the kidneys’ ability to filter blood
• Solid organ transplant — the replacement of a damaged organ with a healthy one
• Structural heart disease — problems with the structure of the heart

Possible Complications When Diagnosed with Viral Diarrhea

Viral gastroenteritis, or stomach flu, can affect anyone, but it hits kids and older people hardest. This condition leads to more illnesses and deaths in these groups. The situation is worse in developing countries, where it often turns deadly for children under 5. Severe stomach flu, especially when caused by a virus called rotavirus, can lead to severe problems like seizures, brain inflammation, or even encephalitis – a dangerous brain infection.

People diagnosed with common variable immunodeficiency, a type of immune disorder, have a higher risk of continuous and recurring Norovirus infections, a common cause of stomach flu. Some patients may continually spread the virus, while others may face serious gut diseases characterized by symptoms including frequent diarrhea, malabsorption problems where their bodies can’t absorb nutrients properly, inflammation, and villi atrophy – a condition where the small, finger-like projections that line the gut wall become damaged.

Common Side Effects:

• Severe impact on young children and older populations
• Higher illness and death rates in these groups
• Potential for severe problems like seizures, brain inflammation, or encephalitis
• Higher risk of continuous and recurring Norovirus infections
• Frequent diarrhea
• Malabsorption problems
• Inflammation
• Villi atrophy

Preventing Viral Diarrhea

The best way to prevent infections from spreading is by practicing good hygiene and taking necessary precautions. This applies to both individuals and communities. One effective method is maintaining a consistent hand washing routine. This involves scrubbing hands with soap and water for at least 20 seconds to prevent passing on infections to those nearby.

However, keep in mind that some viruses, like the Norovirus, are not easily killed by alcohol-based hand sanitizers. In places with a high risk of disease outbreaks like healthcare and care homes, it’s encouraged to perform stringent precautions like thorough handwashing and wearing gloves.

Cleaning the surroundings is another important measure. This includes removing noticeable contamination and then using a chlorine bleach solution, with strength ranging from 1000 ppm to 5000 ppm (parts per million), for disinfection.

Doctors usually suggest that those who are sick remain at home for 2-3 days after their symptoms have alleviated before they go back to work. Measures should also be taken at a public level when an outbreak is traced to a particular food or water source to prevent further spread of the disease.