Evaluation and molecular characterization of human adenovirus in drinking water supplies: viral integrity and viability assays

Fongaro, Gislaine; Nascimento, Mariana A do; Rigotto, Caroline; Ritterbusch, Giseli; da Silva, Alessandra D’ A; Esteves, Paulo A; Barardi, Célia R M

As already reported in the literature, it is important to evaluate viral integrity (state of preservation of viral particles, with undamaged particles being defined as those in which the genetic material is protected by viral capsid) [6] and infectivity, (ability of the virus to replicate in permissive cells) [12] , instead of only evaluating the presence or absence of the viral genome. Therefore, the processed samples were used to evaluate viral integrity (via enzymatic assay with DNase I) and infectivity (via PA and ICC-RT-qPCR-et) of HAdV present in the collected water samples. The majority of samples evaluated in this study contained intact HAdV particles, but this result does not mean that those particles were infectious, as factors such as temperature, pH and UV radiation are known to cause conformational changes in the viral capsid, resulting in Figure 2 Undamaged and infectious HAdV particle: Average number of undamaged and infectious HAdV particle detected in water samples: a) Lagoon water b) Spring source water, and c) Public supply system water. In black bar: undamaged particles; in gray bar: infectious particle, measured by ICC-RT-qPCR assay, and in line: infectious particles, measured by (PA). loss of infectivity [3] . On the other hand, HAdV has the ability to form aggregate particles in the water that protect the individual viral particles from inactivating factors [24] .