Enteroviruses – Infection, Transmission & Diseases
Enterovirus
Enteroviruses are non-enveloped, icosahedral viruses whose genome is in the form of RNA . That is why they belong to the RNA viruses . They multiply in the cytoplasm of the infected host cell. As pathogens in humans, they can lead to many unspecific symptoms, in particular to complaints of the gastrointestinal tract and influenza infections . The frequent occurrence of summer flu in the hot days is often due to enteroviruses. Apart from that, however, they are also the cause of well-known diseases such as polio ( child paralysis ) and hepatitis A.
What are enteroviruses?
Enteroviruses are a genus of viruses comprising a total of 9 species with many different subtypes. They are single-stranded RNA viruses, also known as pico RNA viruses. Enteroviruses have an icosahedral shape and are approximately 25 nm in size on average. They are not shrouded.
The genetic information of these viruses is in the form of RNA, namely as a single strand with positive polarization. Due to the positive polarization, the RNA of the viruses can be directly translated into protein when they multiply in the host cell . In contrast, viruses containing DNA first have to convert their genetic material into RNA.
Occurrence, Distribution & Properties
Enteroviruses are not only found in humans, but also in pigs, rodents, cattle and various species of monkeys. On the other hand, there is no geographical limitation of the distribution area, the enteroviruses occur worldwide. However, some of the diseases they cause are much more common in developing countries, since the necessary preventive measures, such as nationwide vaccination or certain hygienic standards, cannot be implemented sufficiently there. Enteroviruses are acid stable.
As a rule, the following types of enteroviruses relevant to humans are distinguished: polioviruses , hepatitis A viruses , coxsackie viruses , echoviruses and human enteroviruses 68-71 and 73.
Droplet and smear infection are possible transmission routes , with fecal-oral infection (smear infection) being much more common. It can occur, for example, via food or drinking water, toys and hands contaminated with stool or saliva . Swimming pools or lakes contaminated with faeces are also an important source of infection. Infections with enteroviruses therefore occur more frequently in the temperate climate zone in summer.
If a pregnant woman becomes infected with enteroviruses, she can also infect the child via the placenta , which can have serious consequences, including the infant becoming ill with pneumonia .
The incubation period for infection with enteroviruses can be two to 35 days, but usually ranges between five and seven days on average. Enteroviruses multiply after the patient is infected in the patient’s intestinal wall and mesenteric lymph nodes . From there they can enter the patient’s bloodstream ; transient viraemia may occur. It can then infect almost any organ in the body. Therefore, there can also be many different symptoms that alone are not sufficient for a clear clinical diagnosis. Detection is usually via virus cultivation in cell culture or genetic methods such as qr-RT-PCR.
Diseases & Ailments
There is no fixed association between any type of enterovirus and any particular disease. The symptoms are often non-specific and overlap between the different enteroviruses as well as other pathogens. However, some enteroviruses are detected particularly frequently in certain clinical pictures, so that they are considered typical. The most common non-specific symptoms include complaints of the gastrointestinal tract.
Polioviruses, which primarily affect children, cause influenza infections or aseptic meningitis ( inflammation of the brain ), sometimes affecting the central nervous system . The most well-known consequence of an infection with polioviruses is probably polio. Symptoms of polio include fever , fatigue , headache , nausea , body aches , and stiff neck . A permanent paralysishowever, only occurs in some of those infected. The most effective protection against the disease is vaccination. There is no cure for polio. Today, polio is no longer widespread in most countries due to the good vaccination status of the population.
Coxsackie viruses are also the cause of influenza infections, but also lead to infections of the respiratory tract or the heart muscle , as well as hand, foot and mouth disease and Bornholm disease. Newborns and children are particularly at risk from Coxsackie viruses.
Echoviruses express themselves in non-specific febrile illnesses and respiratory infections. Symptoms also include diarrhea . Echoviruses are particularly often detected in aseptic meningitis and inflammation of the pericardium or heart muscle.
The hepatitis A virus is also known as enterovirus 72 and is the causative agent of hepatitis A. After spreading through the blood of the infected person, it affects the liver , which leads to inflammation (hepatitis).
The so-called human enteroviruses 68-71 and 73 usually trigger acute respiratory infections . Sometimes polio-like symptoms also occur.
However, most infections with enteroviruses, up to 90-95%, remain completely symptom-free and therefore often go unnoticed. The therapy of an infection with enteroviruses is symptomatic and depends strongly on which organ system is affected. Drug therapy of the causes is not yet possible. After infection with enteroviruses, the body has persistent serotype-specific immunity against the type of virus with which infection occurred.
Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.