Adenovirus can infect and duplicate in different types of cells and in anatomical sites, such as the breathing apparatus, the eyes, the gastrointestinal and urinary tract and the liver. According to the serogroup, adenovirus can cause epidemics such as conjunctivitis, pharyngitis, whooping cough pneumonia, hemorragical cystitis, gastroenteritis and hepatitis. In particular conditions, adenovirus can even cause the ARD (Acute Respiratory Disease). Adenovirus’ infections in immune-depressed patients can give rise to dangerous complications with an high mortality rate.
Epidemiology
Even though epidemiological characteristics can vary according to the type, every adenovirus is transmitted by direct contact, oral transmission and occasionally by water. Some types can cause an asymptomatic infection, which is persistent in tonsils, adenoids and intestine of infected people. The release of the adenovirus can go on even for months or years. Serotypes 1, 2, 5 and 6 are normally acquired during the childhood and they can cause endemic infections. Serotypes 8, 19 and 37 are associated to epidemic conjunctivitis. Serotypes 40 and 41 cause gastroenteritis, especially in children. In the USA, serotypes 4 and 7 are responsible of the ARD.
For some adenovirus the clinical manifestation depends on the way of acquisition. For example, infections of adenovirus 7, which are acquired by means of inhaling, are associated to dangerous diseases of the breathing apparatus (ARD), while the oral transmission of this virus can cause a softer symptomatology.
Febrile epidemics with conjunctivitis are associated to the water transmission (for example lakes or following a lack of chlorine treatment in swimming pools).
Breathing epidemics of adenovirus are more frequent in late winter, in spring and in summer. Anyway, infections of adenovirus can occur during all the year.
Test
The amplification by means of PCR of a region, which is highly conserved by the Hexon gene (it codifies for a protein) allows to highlight every serogroups of clinically relevant adenovirus in clinical samples. ATTENTION: since adenovirus can stay inactive for a long period of time,
the highlight of the virus is not necessarily correlated to the disease.
Sample taking
Eye smear, pharynx smear, breathing samples, liquor, urine, genital tract and faeces smear.
