Rhinoviruses And Enteroviruses

Colds, sometimes referred to as common colds, are the most common infectious diseases in many countries, so much so that most people are likely to experience them more than once every year. But what is it that causes them exactly? 

Colds are most often caused by a virus, usually a rhinovirus or enterovirus. Rhinoviruses and enteroviruses are very common, highly diverse viruses that affect not just the respiratory airways, but can also involve the digestive system and, in rare cases, the heart and nervous system. 

Keep reading if you want to learn about the similarities and differences between rhinoviruses and enteroviruses, including different types, the organs they affect, the symptoms they cause, how they spread, and how they are treated. 

Overview

Note: rhinoviruses and enteroviruses are both part of the genus enterovirus. To avoid confusion, any mention of enteroviruses in this article refers exclusively to non-rhinovirus enteroviruses.¹

Rhinoviruses and enteroviruses are two distinct groups of viruses that infect humans. While both rhinoviruses and enteroviruses are contagious, they usually result in mild illness, though they can rarely result in severe symptoms. 

Rhinoviruses and enteroviruses include more than 100 types each. To manage this diversity, these have been classified into groups. There are currently three groups of rhinoviruses and twelve groups of enteroviruses.

Rhinoviruses affect the respiratory airways.² They are classified into three groups: A, B, and C. Rhinovirus-C is one of the most common species and the most common in children. If severe, rhinovirus C may cause severe wheezing.³ 

Enteroviruses can infect not only the respiratory airways but often also other regions such as the intestines. The two most common enteroviruses are echovirus and coxsackievirus. Enteroviruses are classified alphabetically into twelve groups ranging from A to L.

Outbreaks of some species of enterovirus have caused concern in the past, especially if they result in severe symptoms. In 2014, an outbreak of enterovirus D68 caused acute flaccid myelitis, a serious condition affecting children that result in muscle weakness.^1,

Rhinoviruses and enteroviruses are among the most common infectious diseases. Despite the mildness of the resulting illness, their prevalence makes them a significant issue for public health, especially for those at the highest risk of developing severe illness such as children, older adults, and people whose immune system has been weakened.

Though enteroviruses and rhinoviruses share some similarities as part of the same family of viruses, they also show some differences. The following sections will describe these in detail. 

What are the similarities between rhinoviruses and enteroviruses? 

While rhinoviruses and enteroviruses are classified as two different groups, they do have some similarities, including genetics, how they store genetic information, how prevalent they are, the regions they infect, how they spread, and the symptoms they present and their severity. But in what ways are they similar, specifically?

They belong to the same family of viruses

After looking into their genetics, rhinoviruses and enteroviruses are closely related, and as a result, they have been grouped under the same genus, enterovirus (though when talking about enteroviruses, rhinoviruses are often excluded), within the family picornaviridae.⁴ 

They store genetic information in the same way

Both rhinoviruses and enteroviruses store their genetic information in RNA, a close “chemical relative” of DNA. While DNA consists of two interweaving string-like structures, called strands, rhinoviruses, and enteroviruses store their genes in a single strand of RNA.⁴

They are very common

Both rhinoviruses and enteroviruses are very common. Rhinoviruses are the most common virus behind common colds (more than half are rhinovirus infections), while enteroviruses are the most common virus in the world.⁵ In more temperate regions, the number of infections by rhinoviruses and enteroviruses peaks in certain seasons, though when exactly depends on the species.⁶ They may affect anyone regardless of age, though they are most common in young children.⁶

They infect respiratory airways

Rhinoviruses and enteroviruses are also similar in that they affect the respiratory tract (made up of the nose, throat, larynx, trachea, bronchi, and lungs). Though enteroviruses are known to infect more body regions, some species - especially Enteroviruses C and D - are exclusively found in the respiratory airways.⁴

They can cause similar symptoms

Infections from both rhinoviruses and enteroviruses usually present no symptoms or mild ones, and only rarely lead to severe illness. These include:

• Coughing
• Sore throat
• Runny nose
• Body aches
• Sneezing
• Fever 

However, on some occasions, they may present with more severe symptoms such as bronchitis or pneumonia in the case of rhinovirus infection, and aseptic meningitis, hepatitis, pancreatitis, as well as brain and heart conditions such as encephalitis and myocarditis in the case of enteroviruses.⁷

What are the differences between rhinoviruses and enteroviruses?

Note to editor(s): consider changing section title e.g. “What are the differences between rhinoviruses and enteroviruses”

While rhinoviruses and enteroviruses share some similarities and belong to the same family, some differences exist between them, especially regarding what organs are affected and the symptoms they may cause.

While both rhinoviruses and enteroviruses can affect the respiratory tract, leading to similar symptoms, enteroviruses can spread to more parts of the body. They may first infect the respiratory airways and intestines, but if they reach the blood and lymph nodes, they can affect the heart (causing myocarditis) and pancreas (causing pancreatitis), and eventually reach the central nervous system, though this is rare.¹ Despite affecting the gastrointestinal tract, enteroviruses are not known to result in symptoms such as diarrhoea or vomiting.⁷

Enteroviruses also include viruses that cause polio (also known as poliomyelitis), a condition that can result in paralysis and death. However, thanks to vaccination efforts, polio has been eradicated in most parts of the world except for some developing countries.

How are rhinoviruses and enteroviruses treated?

Infections with both rhinoviruses and enteroviruses are managed through supportive care, meaning that the illness is waited out with the option to take medication that reduces symptoms such as fever and congestion.¹

Are rhinoviruses and enteroviruses contagious?

Rhinoviruses and enteroviruses are contagious. The most common way of spreading rhinovirus and enterovirus is by coming into contact with viral particles from an infected person either by travelling through the air (such as by coughing or sneezing) or through close contact with the infected person. Some enteroviruses may also enter the body through contaminated food, water, or surfaces that contain faecal matter.⁷ Incubation of enteroviral infections tends to last anywhere from half a day to 5 days,¹ while for rhinoviruses, it usually only takes less than two days.⁸

You can take preventive measures to lower the risk of becoming infected. These include washing your hands thoroughly, avoiding touching your face with unwashed hands, and avoiding close contact with people that are sick. Wearing a mask may be useful when there is a high risk of infection, such as when in contact with someone sick or in crowded spaces. 

Summary

Enteroviruses and rhinoviruses are the most diverse and common culprits behind flu-like illness, resulting in no or mild symptoms in most cases, but can lead to major health issues and severe complications in rare cases. For this reason, it is important for vulnerable populations to be aware of their risk and to take the necessary steps, both individually and in society as a whole, to lower their risk of becoming infected. Therefore, observing good hygiene and seeking medical help if experiencing symptoms can ensure that conditions caused by rhinoviruses and enteroviruses do not lead to more severe symptoms.