Adenovirus infection

Adenovirus infection is a group of anthroponotic acute viral diseases affecting the mucous membranes of the respiratory tract, eyes, intestines and lymphoid tissue mainly in children and young people.

The term "adenoviruses" was proposed by Enders and Francis in 1956, and the diseases caused by this pathogen were referred to as adenoviruses.

ICD-10 codes

• B34.0. Adenovirus infection not specified.
• B30.0. Keratoconjunctivitis caused by adenovirus.
• B30.1. Conjunctivitis caused by adenovirus.

[1], [2]

Epidemiology of adenovirus infection

The source of infection is a sick person who releases the virus into the environment throughout the course of the illness, as well as the virus carrier. Virus isolation occurs from the upper respiratory tract, with feces, tears. The role of “healthy” virus carriers in the transmission of infection is significant enough. The maximum time of virus release is 40-50 days. Adenoviral conjunctivitis can be a nosocomial infection. The transmission mechanism is airborne, fecal-oral. Ways of transmission - airborne, food, contact-household. Possible intrauterine infection of the fetus. Susceptibility is high. Mostly children and young people are sick. Seasonality is not critical, but in the cold season, the incidence of adenoviral infections increases, with the exception of pharyngoconjunctival fever, which is diagnosed in summer. The nature of the epidemic process is largely determined by the serological types of adenoviruses. Epidemics caused by adenovirus types 1, 2, 5, are rare, types 3, 7 are more common. After the illness, a species-specific immunity is formed.

[3], [4], [5], [6], [7], [8], [9]

What causes adenovirus infection?

Pathogens - adenoviruses of the genus Mastadenovirus (mammalian adenoviruses) of the family Adenoviridae. The genus includes 80 species (serotypes).

The family combines viruses with a bare capsid, the average diameter of the virion is 60-90 nm. The mature virus consists of 252 capsomers, including 240 hexones that form faces, and 12 pentones. Forming verticals. The genome is represented by a linear double stranded DNA. Each virion has at least 7 antigenic determinants. Antigenic properties are the basis for the classification of adenoviruses. Nucleocapsid is a single complement-binding antigen of this family. That is why adenoviruses are detected in the RAC using group-specific serum. Hexons contain reactive determinants of the family and type-specific antigens that act upon the release of hexones from the virion and are responsible for the manifestation of the toxic effect. Hexon antigens also contain genus-and group-specific determinants. Pentones contain small antigens of the virus and reactive soluble antigen of the family, found in infected cells. Purified DNA strands contain the main type-specific antigen. Pentones and filaments cause hemagglutinating properties of viruses. Surface antigens of structural proteins are species- and type-specific. The genome is represented by a linear double-stranded DNA molecule.

Adenoviruses are extremely resistant in the environment. Stored in a frozen state, adapt to a temperature of from 4 to 50 ° C. In water at 4 ° C, they remain viable for 2 years: on glass, clothes survive for 10-45 days. Resistant to ether and other lipid solvents. Perish from exposure to ultraviolet radiation, chlorine; at a temperature of 56 ° C die in 30 minutes.

For humans, the pathogens are 49 types of adenoviruses, serovars of types 1, 2, 3, 4, 5, 6, 7, 8, 12, 14, 21 are of most importance, and types 1, 2, 5, 6 often cause disease in preschool children; types 3, 4, 7, 14, 21 - in adults.

Pathogenesis of adenovirus infection

Various organs and tissues are involved in the pathological process: respiratory tract, lymphoid tissue, intestines, bladder, eyes, brain. Adenoviruses of serotypes 3, 4, 8, 19 cause conjunctivitis, and serotypes 40, 41 cause the development of gastroenteritis. Infections caused by serotypes 3, 7, 11, 14. 21, occur acutely with the rapid elimination of the pathogen. Serotypes 1, 2, 5, 6 cause easily flowing diseases, but can persist for a long time in the lymphoid tissue of the tonsils, adenoids, mesenteric lymph nodes, etc. Adenoviruses can penetrate the placenta, causing abnormal development of the fetus, pneumonia of the newborn. Entrance gates of infection - upper respiratory tract or conjunctival mucosa.

Primary replication of the virus occurs in the epithelial cells of the mucous membrane of the respiratory tract and intestines, in the conjunctiva of the eye and lymphoid tissue (tonsils, mesenteric lymph nodes). Adenoviruses, circulating in the blood, affect the vascular endothelium. In the affected cells, intranuclear inclusions of oval or round shape are formed containing DNA. Cells increase, undergo destruction, serous fluid accumulates under the epithelium. This leads to exudative inflammation of the mucous membranes, the formation of fibrinous films and necrosis. Lymphoid infiltration of the deep layers of the trachea and bronchus walls is observed. In the lumen of the bronchi contains serous exudate mixed with macrophages and single leukocytes.

In young children, viruses can reach the alveoli by bronchogenic means, causing pneumonia. In addition to local changes, adenoviruses have a general toxic effect on the body, which is expressed by symptoms of intoxication.

[10], [11], [12]

Symptoms of adenovirus infection

The incubation period lasts from 5 to 14 days.

Adenovirus infection is distinguished by the polymorphism of clinical symptoms and syndromes. The clinical picture may be dominated by symptoms that indicate lesions of the respiratory tract, eyes, intestines, and bladder. Lymphoid tissue. Perhaps the development of meningoencephalitis. In adults, adenovirus infection occurs more often in a latent form, in young people - in a clinically pronounced. The disease develops gradually. The temperature rises from the first day of illness, its duration varies from 5-7 days to 2 weeks. Sometimes subfebrile condition lasts up to 4-6 weeks, there may be two-wave fever, rarely three waves are observed. In most cases, symptoms of intoxication are moderately pronounced even with high fever.

Since the adenoviruses are trophic to the lymphoid tissue, nasopharyngeal tonsils are involved in the process from the first days of the disease and there is difficulty in nasal breathing, facial puffiness, serous rhinitis with abundant discharge (especially in younger age groups). A characteristic symptom of the disease is pharyngitis with a pronounced exudative component. Pharyngitis is characterized by moderate pain or sore throat. On examination, hyperplasia of lymphoid follicles is revealed against the background of edematous and hyperemic mucosa of the posterior pharyngeal wall. Tonsils are enlarged, in some patients white tender patches are visible, which are easily removed with a spatula.

In adults, unlike children, clinical signs of bronchitis are rarely detected. For children characterized by moderate short cough with scanty mucous discharge. In addition, almost every fifth sick child develops acute stenosing laryngotracheitis, which is difficult, with a pronounced exudative component. Some children develop obstructive syndrome, which has a puffy or mixed form. It can last up to 3 weeks. In this case, the cough is wet, obsessive; exhalation is difficult, dyspnea mixed type. Auscultatory is determined by a large number of wet variegated and single dry rales. In young children may develop bronchitis obliterans.

Often, adenoviral infection is accompanied by moderate lymphadenopathy. The cervical, submandibular, mediastinal and mesenteric lymph nodes are enlarged. Mesadenitis is manifested either against the background of other manifestations of adenoviral infection, or as the main syndrome. The main clinical sign is acute paroxysmal pain mainly in the lower abdomen (in the right iliac, paraumbilical areas). Often there is nausea, less vomiting, diarrhea. Changes in the cardiovascular system are practically absent. In some patients, hepatolienal syndrome occurs, sometimes with increased activity of aminotransferases (ALT, ACT).

Conjunctivitis often develops. At first it is one-sided, later the second eye is affected. There are catarrhal, follicular and membranous conjunctivitis. The latter form is most typical. The conjunctiva of the eyelids is hyperemic, granular, somewhat swollen; perhaps a small secretion. After 1-3 days on the conjunctiva appear white or grayish-white film raids. A common symptom is swelling of the eyelids. Rarely, keratoconjunctivitis is observed, in which infiltration is formed in the subepithelial layer of the cornea, clouding of the cornea occurs, and visual acuity decreases. The process lasts up to one month and, as a rule, is reversible.

In adults with adenovirus infection, there may be clinical signs of cystitis. Cases of the acute encephalitis caused more often by a serotype 7 adenovirus are described. Pharyngoconjunctival fever, which has a fairly clear clinical picture, with a high 4-7-day fever, intoxication, rhinopharyngitis, and membranous conjunctivitis has been isolated into an independent form of the disease.

[13],

Complications of adenovirus infection

Frequent complications - otitis, sinusitis and pneumonia, developing as a result of the accession of a secondary infection. Often, on the background of adenovirus infection, exacerbation of chronic tonsillitis occurs. Cases of complications of adenoviral mesadenitis with intestinal invagination are described.

[14], [15], [16], [17]

Diagnosis of adenovirus infection

Clinically, adenovirus infection is diagnosed by the presence of conjunctivitis, pharyngitis, lymphadenopathy in the presence of fever.

The blood picture in adenovirus infection is non-specific and has no diagnostic value. Serological diagnosis is used for retrospective interpretation of the etiology of SARS. RTGA and RSK are widely used. Methods of rapid diagnosis are represented by the reaction of indirect haemadsorption, ELISA and REEF. They allow for 3-4 hours to detect adenovirus antigens in epithelial cells of the nasal cavity. Cell scraping takes place in the first days of the infection process. Detection of viral antigens in the nuclei of epithelial cells indicates the latent course of the infectious process, the presence of antigens in the cytoplasm allows us to diagnose an acute disease. Virus isolation in tissue culture is used for scientific purposes.

[18], [19], [20], [21],

Differential diagnostics

Differential diagnosis is performed with SARS of a different etiology, oropharyngeal diphtheria, eye diphtheria, tonsillitis. Adenovirus infection has a number of similar symptoms with infectious mononucleosis, typhoid fever. Yersiniosis also occurs with symptoms of pharyngitis, conjunctivitis, hepatolienal syndrome, diarrhea and prolonged fever.

[22], [23], [24], [25]

Indications for consulting other specialists

Indication for consulting a surgeon - the development of adenoviral mesadenitis, occurring with severe abdominal pain and vomiting. An ophthalmologist's consultation is indicated for eye damage.

[26], [27], [28], [29]

Indications for hospitalization

The treatment of most patients is carried out at home. Patients with severe form of the disease, with complications, concomitant diseases, as well as for epidemiological indications are subject to hospitalization.

[30], [31], [32], [33], [34]

Treatment of adenovirus infection

Mode and diet

In the febrile period shows bed rest. A special diet is required.

[35], [36], [37], [38],

Drug treatment

In most cases, with an uncomplicated form of adenoviral infection, etiotropic therapy is not prescribed. In case of severe infection, it is possible to prescribe arbidol, interferon preparations and its inductors. Among human leukocyte interferon drugs used: human leukocyte interferon dry 2 times a day in both nasal passages of 5 drops (0.25 l), interlock 1 drop 10 times a day in each eye (for the treatment of conjunctivitis), leukinferon for injection dry (injected in oil, inhalation) 100 thousand ME. Antibiotics are indicated when attaching a secondary bacterial infection.

[39], [40], [41], [42],

Clinical examination

Dispensary observation is not carried out.

[43], [44], [45], [46], [47], [48],

How is adenovirus infection prevented?

In the prevention of adenoviral diseases, the main role belongs to the methods of increasing the nonspecific resistance of the organism (hardening, rational nutrition). During epidemic outbreaks, interferon or drugs from the group of interferon inductors are prescribed to contact persons. In the outbreak carry out the current disinfection. During outbreaks of adenoviral infections, children are separated for at least 10 days after the last patient is identified.

[49], [50], [51], [52]

What is the prognosis of adenovirus infection?

The prognosis is usually favorable. Discharge from the hospital is carried out after clinical recovery.