Norovirus and enterovirus are common viruses that cause numerous infections annually. Although both are widespread, they belong to different viral families, resulting in distinct illnesses, symptoms, and modes of transmission. Understanding these differences is helpful for the recognition, prevention, and management of the sickness they cause.
Viral Characteristics and Transmission
Norovirus and enterovirus are both RNA viruses from separate families, which dictates their behavior and spread. Norovirus, from the Caliciviridae family, is highly contagious. As few as 10 to 18 viral particles can be enough to make a person sick, and high concentrations are shed in the feces and vomit of an infected individual.
The structure of norovirus makes it resilient, allowing it to survive on surfaces for up to two weeks and withstand freezing, heating, and many alcohol-based hand sanitizers. Its primary transmission route is fecal-oral, occurring through direct contact, consuming contaminated food or water, or touching contaminated surfaces. Aerosolized particles from vomit can also lead to infection.
Enteroviruses are part of the Picornaviridae family. While also transmitted via the fecal-oral route, they can also spread through respiratory secretions from a cough or sneeze. This dual-transmission capability allows enteroviruses to circulate efficiently, especially in settings with close contact like schools and childcare centers.
Distinguishing Symptoms
The illnesses caused by these viruses are markedly different. Norovirus infection leads to acute gastroenteritis, often mislabeled as the “stomach flu,” though it is not related to the influenza virus. The onset of symptoms is sudden, appearing 12 to 48 hours after exposure, and includes severe vomiting, watery diarrhea, nausea, and stomach cramping.
These symptoms are short-lived, with most people recovering within one to three days. While the illness is brief, the symptoms can lead to significant fluid loss. A low-grade fever, headache, and body aches may also accompany the primary gastrointestinal issues.
In contrast, enterovirus describes a group of viruses that can cause a wide spectrum of diseases, and many infections are asymptomatic. When symptoms appear, they can range from a mild febrile illness to conditions like herpangina and Hand, Foot, and Mouth Disease, which involve respiratory symptoms, rashes, or mouth sores.
A small fraction of enterovirus infections lead to severe conditions affecting the nervous system. These rare outcomes can include aseptic meningitis or acute flaccid myelitis (AFM), which causes sudden muscle weakness. This potential for varied systemic illness sets enteroviruses apart from the predictable gastrointestinal symptoms of norovirus.
Seasonality and Vulnerable Groups
Norovirus and enterovirus have different seasonal patterns and affect different groups. Norovirus activity peaks from late fall through early spring, from November to April, earning it the nickname “winter vomiting bug.”
Norovirus can infect people of all ages. The consequences can be more severe for the very young, older adults, and individuals with compromised immune systems who are at greater risk for dehydration. Dehydration is the most common complication and the primary reason for hospitalization.
Enterovirus infections tend to peak during the summer and fall. The groups most commonly affected are infants, children, and teenagers. This is because adults are more likely to have developed immunity from previous infections with various enterovirus types.
Prevention and Medical Management
For norovirus, its resistance to alcohol-based sanitizers means handwashing is a priority. Thoroughly washing hands with soap and water for at least 20 seconds is more effective at removing viral particles. Disinfecting contaminated surfaces requires a bleach-based solution to inactivate the virus.
Preventing enterovirus spread involves standard hygiene. Frequent handwashing with soap and water is effective, as is teaching children to avoid touching their eyes, nose, and mouth. Since enteroviruses can spread through respiratory droplets, covering coughs and sneezes also helps reduce transmission.
There are no public vaccines to prevent either norovirus or the most common enterovirus infections. Since both illnesses are caused by viruses, antibiotics are ineffective. Medical management for both is supportive, aiming to relieve symptoms and prevent complications while the body fights the infection.
For both viruses, maintaining hydration is the main focus of care, and oral rehydration solutions can help replace lost fluids and electrolytes. Seek medical attention for a norovirus infection if there are signs of severe dehydration, like a lack of urination or dizziness. For enterovirus, medical evaluation is recommended for a high fever with a severe headache, a stiff neck, or difficulty breathing, which could indicate neurological issues.