Enteroviruses

We  all have heard about the disabling disease polio, which is caused by the polio virus. Poliovirus is a type of eneterovirus, a group of viruses that enter the human gut and survive there for years; often affecting other organs like the nervous system, as in the case of the polio virus. Unfortunately, they are extremely common and one of the major reasons for diseases in humans and mammals, second only to the cold and cough viruses.

Other than the three types of polio viruses, there are 58 other non polio enteroviruses that can affect humans. The common ones are Coxsackie virus, HMV and Echo viruse that can be found in respiratory secretions, nasal mucus, and stool. These enteroviruses stay in the human body for several years and can cause disease at any point of time after initial infection, although many of them may cleared off off without causing harm.

Enterovirus infections are very common in summer and fall with at least 1 billion people on the planet infected each year. This is a big number as they are extremely contagious   and spread through  the fecal and oral route. Infants are the first victims as  they have less immunity against these infections. It is believed that every child will suffer from one enterovirus infection a year with very rare chances of complications. Adults develop immunity against these viruses and are not common victims, although, those with pre existing medical conditions may have a difficult time reaching remission.

Why are enteroviruses in news these days? It is fall time and enterovirus D 68 has been detected and its presence confirmed in six states of the US including Colorado, Illinois, Iowa, Kansas, Kentucky and Missouri. It is also feared to have spread to Washington, though the CDC has not yet found its traces.

The reason beind the fear is that firstly, this small single stranded RNA virus is associated with some serious organ diseases such as myocarditis of heart, aseptic encephalitis of the brain, Type 1 diabetes, hand mouth and foot disease, ADHD, herpangina, polio and paralysis, pleurodynia of lungs and tricky chronic fatigue syndrome. Secondly, the virus can survive the highly acidic gut environment as well as  bleaching and freezing. It can stay on for days on floor mats and door handles as well. On the other hand, it can be easily destroyed by heat and disinfectant liquids like hand wash, etc. So it is important to frequently wash hands, especially before food and after contact with an infected person.

There are no standard serological tests to identify all the enteroviruses, as antibodies for only few of them like the coksackie B virus can be detected in the infected person’s blood. However, the virus can be isolated from infected body fluids using the PCR method, which is a highly sensitive and specific method for detecting viruses.

There are no standard medications to kill the virus and so prevention is the best way. Pleconaril is one drug that prevents binding of enterovirus  and intravenous immunoglobulin therapy is highly useful in case of serious infections like myocarditis andencephalitis. For serious victims, beta interferon therapy can be used; however, it is to be noted that these therapies are extremely costly.

Due to  lack of standard medications, it is vital to boost  immunity to fight the disease when it occurs. Commercially available immunity boosters, balanced diet and exercise are used to fight the infection, yet, soap and water are still the cheapest and most effective ways to prevent the spread.