Detection of Adenoviruses (AdV) in Culture-Negative Environmental Samples by PCR during an AdV-Associated Respiratory Disease Outbreak

Abstract

Since 1954, adenoviruses (AdV) have been recognized as an important cause of acute respiratory disease (ARD) among U.S. military recruits. Until recently, routine oral vaccination for AdV serotypes 4 and 7 eliminated epidemic AdV-associated ARD in this population. Now that the manufacturer has ceased production, vaccination has ended and AdV epidemics have reappeared. As part of a prospective epidemiological study during the high-risk ARD season, serial samples were obtained from ventilation system filters and tested for AdV by culture and PCR. An outbreak occurred during this surveillance. Of 59 air filters, 26 (44%) were AdV positive only by PCR. Sequence analysis confirmed the presence of AdV serotype 4, the implicated outbreak serotype. The number of AdV-related hospitalizations was directly correlated with the proportion of filters containing AdV; correlation coefficients were 0.86 (Pearson) and 0.90 (Spearman's rho). This is the first report describing a PCR method to detect airborne AdV during an ARD outbreak. It suggests that this technique can detect and quantify AdV-associated ARD exposure and may enable further definition of environmental effects on AdV-associated ARD spread.

Detection of viruses in used ventilation filters from two large public buildings

“…It is possible that the conditions used for virus isolation might not have been optimal for all viruses, although we used 2 blind passages in 3 different cell lines and SPF chicken eggs. This is in agreement with the findings of Echavarria et al, 23 who could not isolate adenovirus from the implicated ventilation filters during an outbreak of adenovirus infection but could detect viral nucleic acids in many of the filters. The authors sampled filter surfaces by wiping them with swabs premoistened with cell culture medium.…”

“…8,22 Although these filters are not designed specifically to capture virus-sized particles and have not been evaluated as such, they can be expected to trap viral aerosols because they filter large volumes of air continuously, and aggregates of viruses and particles laden with one or more viruses are likely to be deposited on their surfaces. The role of ventilation filters in the epidemiology of adenovirus-related respiratory disease was documented by Echavarria et al, 23 who conducted a study in buildings occupied by unvaccinated US Army trainees for adenovirus-related infections. The percentage of filters that were positive for adenovirus type 4 by polymerase chain reaction (PCR) analysis was directly proportional to the number of hospitalizations of the trainees housed in those buildings, indicating that these filters could trap the aerosolized infectious pathogens.…”

Transmission Dynamics and Prospective Environmental Sampling of Adenovirus in a Military Recruit Setting

“…Despite evidence of an increased environmental burden of adenovirus concomitant with human infection, the prediction of the outbreak was not demonstrated. Air-filte detection of adenovirus concomitant with an outbreak was reported by Echavarria et al [32] in 2000; during an adenovirus outbreak among Army recruits, 26 (44%) of 59 filter from the ventilation system were found to be positive by PCR, although none tested positive by cell culture. However, no surface sampling was performed in that study.…”

Transmission routes of respiratory viruses among humans

“…During a military training period, increased numbers of adenovirus infections occurred over time, which correlated with an increased detection of PCR-positive air filters. Additionally, a correlation between disease and the extent of ventilation was observed, with more ventilation resulting in fewer disease cases [103 ]. In a more recent study in military recruits, positive viral DNA samples were mainly obtained from pillows, lockers and rifles, although adenovirus DNA was also detected in air samples.…”