Adenoviral infection – a disease from the group of SARS caused by an adenovirus and characterized by the development of rhinopharyngitis, laryngotracheobronchitis, conjunctivitis, lymphadenopathy, dyspeptic syndrome. In the overall structure of acute respiratory infections adenovirus infection is about 20%. Most sensitive to adenoviruses demonstrated by children from 6 months to 3 years. It is believed that at preschool age, almost all children suffer one or more episodes of adenovirus infection. Sporadic cases of adenovirus infections are year-round; in cold season, the incidence is in the nature of epidemic outbreaks. Close attention to adenoviral infection is confined with infectious diseases, Pediatrics, otolaryngology, ophthalmology.
Causes of adenovirus infection
Currently there are more than 30 serovars of viruses of the family Adenoviridae, causing human disease. The most common cause of outbreaks of adenovirus infections in adults are 3, 4, 7, 14 and 21 serotypes. Serovar types 1, 2, 5, 6 usually affects pre-school children. Pathogens pharyngoconjunctival fever and adenoviral conjunctivitis in the majority of cases are serotypes 3, 4, 7.
The virions of the causative agent contain double-stranded DNA, have a diameter of 70-90 nm and a three-antigen (group-specific A-antigen; determining the toxic properties of adenovirus To the serotype antigen and S-antigen). Adenoviruses are relatively resistant in the environment: under normal conditions persisted for 2 weeks, tolerate low temperature and desiccation. However, the causative agent of adenoviral infection inactivated when exposed to UV rays and chlorinated disinfectants.
Adenoviruses are spread from the sick people who are isolated pathogen from nasopharyngeal mucus and faeces. From here there are 2 main ways of infection in the early period of the disease — airborne; in the late — fecal-oral – in this case, the disease occurs by type of intestinal infections. Possible water route of infection, therefore, adenoviral infection is often called a “disease of the swimming pools.” The source of adenoviral infection can be virus carriers, patients with asymptomatic and blurred forms of the disease. Immunity after the previous infection type-specific, so the possible recurrence caused by a different serotype of the virus. Found in nosocomial infection, including during the parenteral treatment procedures.
Adenovirus can enter the body through mucous membranes and upper respiratory tract, intestinal tract or the conjunctiva. The replication of the virus occurs in the epithelial cells, regional lymph nodes and the lymphoid formations of the intestine, which coincides with the incubation period of adenovirus infection. After the death of infected cells viral particles are released and penetrate into the bloodstream, causing viremia. Changes develop in the nose, tonsils, posterior pharynx, conjunctiva; inflammation is accompanied by severe exudative component, which causes the appearance of serous discharge from the nose and conjunctiva. Viremia may lead to involvement in the pathological process of the bronchi, digestive tract, kidneys, liver, spleen.
The symptoms of adenovirus infection
The main clinical syndromes, the form of which can accept adenoviral infection are: Qatar Airways (nasopharyngitis, tonsillopharyngitis, laringotraheobronhit), pharyngoconjunctival fever, acute conjunctivitis and keratoconjunctivitis, diarrheal syndrome. For adenoviral infection can be light, moderate and severe; uncomplicated and complicated.
The incubation period for adenovirus infection lasts 2-12 days (usually 5-7 days), after followed by a symptomatic period with a consistent onset of symptoms. Early signs are increased body temperature to 38-39 °C and moderately expressed symptoms of intoxication (lethargy, poor appetite, muscle and joint pain). Simultaneously with the fever occur catarrhal changes in the upper respiratory tract. Appear serous nasal discharge, which then becomes Muco-purulent; difficult nasal breathing. In moderate redness and swelling of the mucous membrane of the posterior pharyngeal wall, point a whitish coating on the tonsils. In adenoviral infection occurs, the response of the submandibular and cervical lymph nodes. In the case of laringotraheobronhit there is hoarseness, dry barking cough, possible shortness of breath, the development of laryngospasm.
The defeat of the conjunctiva with adenovirus infection can occur by type catarrhal, follicular or membranous conjunctivitis. Usually in the pathological process of the eye are involved by turns. Worried about stinging, burning, lacrimation, the feeling of presence of a foreign body in the eye. On examination revealed moderate redness and swelling of the eyelids, hyperemia and granularity of the conjunctiva, the sclera inetsirovany, sometimes the presence of a dense grayish-white film on the conjunctiva. In the second week of the disease the conjunctivitis can join signs of keratitis.
If adenovirus infection occurs in the intestinal form, there are paroxysmal pain in the umbilical and right iliac region, fever, diarrhea, vomiting, mesenteric lymphadenitis. When expressed pain syndrome clinic resembles acute appendicitis.
Fever with adenovirus infection lasts 1-2 weeks and can wear a wavy character. Signs of rhinitis and conjunctivitis subside in 7-14 days, Qatar the top respiratory ways – through 14-21 days. In severe form of the disease affects parenchymal organs; may occur meningoencephalitis. In children the first year of life often develop adenoviral pneumonia and severe respiratory failure. Complicated for adenovirus infection is usually associated with the layering of secondary infection; the most frequent complications are sinusitis, otitis media, bacterial pneumonia.
Diagnosis and treatment of adenovirus infection
Detection of adenovirus infection is usually made based on clinical data: fever, respiratory catarrh, conjunctivitis, poliadenit, sequential development of symptoms. Methods of rapid diagnosis of adenoviral infection is the reaction of immunofluorescence and immune electron microscopy. Retrospective confirmation of the etiological diagnosis is carried out by methods ELISA, HAI, RAC. Virological diagnosis involves the release of adenovirus from nasopharyngeal swabs, conjunctival scrapings and faeces of the patient, however due to the complexity and duration is rarely used in clinical practice.
Differential diagnostics of various clinical forms of adenovirus infection is carried out with influenza, other respiratory catarrh, diphtheria of the pharynx and eyes, infectious mononucleosis, mycoplasmal infection, yersiniosis. For this purpose, and to assign the local etiotropic treatment, patients need to consult a ophthalmologist and otolaryngologist.
Common etiotropic therapy is drugs antiviral action ( umifenovir, ribavirin, the drug of antibodies to gamma interferon person). Local therapy of adenovirus infection include: instillation of eye drops (solution DNase or sulfatsil sodium), application of acyclovir as eye ointment for the eyelid, intranasal application oksolinovoj ointments, and endopharyngeal endonasal instillation of interferon. Symptomatic and posindromnoy therapy: inhalation, ingestion antipyretic, antitussive and expectorant drugs, vitamins. In adenoviral infection, burdened by bacterial complications, antibiotic treatment.
Prognosis and prevention of adenovirus infection
Uncomplicated forms of adenoviral infection end favorably. Deaths may occur in children of early age in connection with the occurrence of severe bacterial complications. Prevention is similar to prevention of other respiratory viral infections. During periods of epidemic outbreaks shows the isolation of patients; carrying out of current disinfection, ventilation and UVI premises; the interferon to the persons subjected to the risk of infection. Specific vaccination against adenoviral infection has not yet been developed.