The wide pantropicity of enteroviruses underlies a wide variety of clinical forms of infection caused by them, affecting almost all organs and tissues of the human body: nervous, cardiovascular systems, gastrointestinal, respiratory tract, as well as kidneys, eyes, skin muscles, oral mucosa, liver, endocrine organs. Enterovirus infections are especially dangerous in immunodeficient individuals.
Most cases of enterovirus infections are asymptomatic. Most clinically noticeable manifestations are colds-like diseases, and enteroviruses are considered the second most common causative agent of acute respiratory viral infections.
Conventionally, two groups of diseases caused by enteroviruses can be distinguished:
- Potentially severe:
– serous meningitis;
– acute paralysis;
– neonatal septic-like diseases;
– myo- (peri-) carditis;
– chronic infections of immunodeficient individuals.
- Less dangerous:
– a three-day fever with or without rash;
– vesicular pharyngitis;
- Herpetic tonsillitis. On the first day of the disease, red papules appear, which are located on a moderately hyperemic mucosa of the palatine arches, tongue, soft and hard palate, quickly turn into vesicles 1-2 mm in size, from 3-5 to 15-18, not merging with each other. After 1-2 days, the vesicles open with the formation of erosion or dissolve without a trace by 3-6 days of illness. Pain when swallowing is absent or insignificant, sometimes salivation occurs. The increase in cervical and submandibular lymph nodes is small, but their palpation is painful.
- Epidemic myalgia (Bornholm disease, “damn dance”, pleurodinia). It is characterized by acute pain with localization in the muscles of the anterior abdominal wall of the abdomen, lower chest, back, and limbs. The pains are paroxysmal in nature, lasting from 30–40 seconds to 15–20 minutes, are repeated for several days, can be recurrent in nature, but with less intensity and duration.
- Meningeal syndrome persists from 2–3 days to 7–10 days; cerebrospinal fluid rehabilitation occurs in the 2nd – 3rd week. Residual effects in the form of asthenic and hypertensive syndromes are possible.Other neurological symptoms in case of enteroviral etiology meningitis can include impaired consciousness, increased tendon reflexes, lack of abdominal reflexes, nystagmus, foot clonus, short-term oculomotor disorders.
- The paralytic forms of enterovirus infection are distinguished by polymorphism: spinal, bulbospinal, pontine, polyradiculoneuric forms may develop. More often than others there is a spinal form, which is characterized by the development of acute flaccid paralysis of one or both legs, less often – hands with severe pain of a muscular nature. The course of these forms is easy, does not leave persistent paresis and paralysis.
- Enterovirus fever (minor illness, 3-day fever). This is the most common form of enterovirus infection, but difficult to diagnose with sporadic morbidity. It is characterized by short-term fever without pronounced symptoms of local lesions. It proceeds with mild general infectious symptoms, little well-being is disturbed, there is no toxicosis, the temperature persists for 2–4 days. Clinically, it can be diagnosed in the presence of an outbreak in the team, when other forms of enterovirus infection are found.
- Enterovirus exanthema (“Boston fever”). It is characterized by the appearance from the 1st to 2nd day of illness on the face, trunk, limbs of the rashes of a pink color, spotty or spotty-papular in nature, sometimes there may be hemorrhagic elements. The rash lasts 1-2 days, less often – longer and disappears without a trace.
- Intestinal (gastroenteric) form. It occurs with watery diarrhea up to 5-10 times a day, abdominal pain, flatulence, infrequent vomiting. Symptoms of intoxication are moderate. In children under 2 years of age, intestinal syndrome is often combined with catarrhal phenomena from the nasopharynx. The duration of the disease in young children for 1-2 weeks, in older children 1-3 days.
- The respiratory (catarrhal) form is manifested by mild catarrhal phenomena in the form of nasal congestion, rhinitis, and dry, rare cough. On examination, hyperemia of the mucous membrane of the oropharynx, soft palate and posterior pharyngeal wall is revealed. Mild dyspeptic disorders may be noted. Recovery occurs in 1–1.5 weeks.
- Myocarditis, newborn encephalomyocarditis, hepatitis, damage to the kidneys, eyes (uveitis) – these forms of enterovirus infection in children are rare. Clinical diagnosis of them is possible only in the presence of manifest forms of enterovirus infection or epidemic outbreaks of the disease. More often they are diagnosed during virological and serological studies.
The high tropism of enteroviruses to the nervous system is characterized by a variety of clinical forms of the most common lesions of the nervous system: serous meningitis, encephalitis, polyradiculoneuritis, facial neuritis.
The leading place among childhood neuroinfections is still occupied by meningitis, which accounts for 70–80% of the total number of infectious lesions of the central nervous system. An increase in the incidence of enteroviral meningitis in the summer-autumn period is noted annually. Mostly children of preschool and school age are affected. Clinically, aseptic serous meningitis caused by different types of polioviruses, ECHO viruses, Coxsackie A and B viruses, is almost impossible to distinguish. Changes in cerebrospinal fluid are also indistinguishable. To date, the most common clinical form of enteroviral meningitis has been well described.
According to the WHO, enterovirus infections of the heart are a regularly reported pathology in the world. Depending on the causative agent, enteroviral heart infections have a well-defined share in the structure of the total infectious morbidity, which makes up about 4% of the total number of registered viral diseases. The largest number of enterovirus infections of the heart is caused by Coxsackie B viruses, second place among causative agents of enterovirus infections of the heart (by specific gravity in infectious diseases) is occupied by Coxsackie A viruses, followed by ECHO viruses and polioviruses.
The following clinical forms of virus-induced heart diseases are distinguished: myo-, peri-, endocarditis, cardiomyopathies, congenital and acquired heart defects.
The clinical manifestations of enterovirus infections of the heart depend on the degree of involvement of the myocardium in the pathological process and can be accompanied by almost complete absence of impaired functional activity of the myocardium, or severe damage to cardiac activity, accompanied by dilatation of all heart chambers with significant impairment of systolic function. Enteroviruses have a high tropism for heart tissues, in which alternatively destructive processes first develop due to the direct cytopathic effect of the virus, and subsequently there is a virus-induced inflammation with the formation of myo-, endo- and epicarditis, diffuse cardiosclerosis, leading to the development of dilated cardiomyopathy.
Of interest are reports of vascular lesions in Coxsackie infections detected in patients with entroviral myocarditis.
Enterovirus 70 in recent years has caused numerous outbreaks of acute epidemic hemorrhagic conjunctivitis, prone to spread. In some patients, after a period of time from the onset of the disease, paralysis and paresis of various severity and localization developed. There are uveitis caused by ECHO 11, 19.
Enterovirus infections pose the greatest danger for immunosuppressive individuals: patients with malignant blood diseases, newborns, people after bone marrow transplantation, and HIV-infected patients.
Coxsackie A9 virus infection is associated with the development of autoimmune diseases. The role of enteroviruses in the development of type 1 diabetes has been proven.
The literature discusses the role of enterovirus infections, in particular Coxsackie-Virus, in the etiology of spontaneous miscarriages.
The defeat of the genital area is manifested by the clinic of parenchymal orchitis and epididymitis, most often caused by the Coxsackie viruses B1-5, ECHO 6, 9, 11. Enteroviruses as the cause of infectious orchitis take the second place after the mumps virus. The peculiarity of this disease is that at the first stage, a clinic of another symptom complex, characteristic of enterovirus infection (herpangina, meningitis, etc.) develops, and after 2-3 weeks there are signs of orchitis and epididymitis. The disease occurs in children of puberty and proceeds relatively benignly, but can also end with the development of azoospermia.