Adenoviruses cause various diseases including pneumonia, cystitis, conjunctivitis, diarrhea, hepatitis, myocarditis and encephalitis. In short, adenoviruses can be found in almost every system and every organ of the human body. Infections can occur at any time of the year and in all age groups.
Cultures in cell lines are the reference method for the diagnosis of adenovirus infections, but may take up to 3 weeks to complete. Serological tests are much faster, but less sensitive than cell cultures. Molecular testing with PCR provides a rapid, specific and sensitive means of diagnosis by detecting adenovirus DNA.
More information on Adenoviruses
Adenoviruses cause various diseases, the most important of which are upper respiratory tract infections (sometimes the lower respiratory tract), ophtalmic and gastrointestinal infections.
Adenoviruses are icosahedral-shaped viruses without envelopes, 70-90 nm in size. Their morphogenesis takes place in the nucleus of the infected cells, where they aggregate to form large crystals. Their genome is linear, double-stranded DNA. Thus far they have been classified into 51 different serotypes and 6 groups.
They can mainly affect epithelial cells in the eyes, pharynx, respiratory system and gastrointestinal tract. After a 5-10 day incubation period, various symptoms may occur depending on the site of infection:
|Respiratory||Symptoms take the form of rhinitis or non-bacterial pharyngitis, depending on the type of virus and the condition of the patient. Acute, flu-like syndrome can develop and, especially in young children, develop into a potentially dangerous pneumonia.||Type 1, 2, 5 and 6|
|Eye||Isolated symptoms can occur, but they usually coexist with pharyngitis, ranging from follicular conjunctivitis to corneal conjunctivitis which can even cause permanent partial loss of vision||Type 3 and 7|
|Gastrointestinal||Two serotypes are causally related to infant gastroenteritis and may account for 5-15% of cases of viral gastroenteritis. Adenoviruses are abundant in diarrheal stools||Type 40 and 41|
Generalized infection of the population by adenoviruses begins early in childhood, so adenovirus infections play a more important role in children than in adults. Approximately 5% of all common colds in children under the age of 5 may be due to adenoviruses, and they are the second most common cause of viral diarrhea after rotavirus.
Respiratory adenoviruses are transmitted mainly by droplets, but also by faeces as viruses are also excreted in faeces. Ophthalmic infections can occur from the water in swimming pools or in the case of adenovirus type 8, iatrogenically from inadequately sterilized ophthalmic tools. Intestinal infections are also transmitted via the faecal-oral route, mainly by contact rather than through contaminated water or food. Adenoviruses can remain asymptomatic for up to 18 months after infection or enter a latent phase and then reactivate.
Unlike most respiratory viral infections, adenoviruses induce effective and long lasting immunity against re-infections. This may be due to the fact that adenoviruses also infect peripheral lymph nodes and lymphoid cells in the gastrointestinal tract. Disease resistance appears to be directly related to the presence of circulating neutralizing antibodies, which may remain for a lifetime. Maternal antibodies usually protect infants against severe respiratory infections from adenoviruses.
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. Correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.