Prevalence and genotypes of the adenovirus infection as well detection of co-infection with bocavirus in Mexican immunosuppressed and non-immunosuppressed children with pneumonia.

Background: Adenovirus (AdV) causes respiratory infection; recent observations suggest that some subtypes have more ability to develop fatal disease. AdV infection has been associated with co-infection with human bocavirus (HBoV). We analysed the frequency of AdV infection, its subtypes and the presence of co-infection with HBoV, as well the clinical characteristics of such co-infection in Mexican paediatric immunosuppressed (IP) and non-immunosuppressed patients (non-IP) diagnosed with pneumonia.

Methods: A total of 5185 nasopharyngeal swabs from two groups of children with pneumonia, one IP and the other non-IP, were analysed for the detection of AdV by immunofluorescence and confirmed by PCR and culture. HBoV was identified by PCR. Positive samples for AdV and AdV/HBoV were typed using PCR sequencing, the clinical characteristics of the AdV/HBoV co-infection were analysed.

Results: Thirty-seven of the 5185 (0.71%) samples were positive for AdV, of those 27/37 (73%) were detected in non-IP and 10/37 (27%) in the IP group. Twelve were typed as follows: 9/12 (75%) as Species B1 subtype 3, of those 8/9 (88.9%) in non-IP and 1/9 in the IP group. One of twelve AdV2 subtype B11a was identified in one non-IP and the remaining two out of 12 successfully typed, were identified as Species C subtypes 2 and 6 in the group of non-IP. The presence of both AdV and HBoV1 in co-infection was observed in 2/37 (5.4%) non-IP with a syndrome like influenza.

Conclusions: In this 5 year analysis of samples from non-IP and IP hospitalized paediatric patients with a diagnosis of pneumonia, a low incidence of AdV was found. B1 was the most frequent subtype and frequently found in non-IP, and two cases of co-infection AdV/HBoV1 were detected in two non-IP with a influenza-like syndromes. This is the first report of HBoV and AdV co-infection in Mexico. The frequency of AdV and HBoV co-infection was lower than that reported in other populations.