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

The integrity of HAdV particles was positively correlated with their infectiousness, as evaluated by ICC-RT-qPCR, which corroborates other studies that have reported that enzymatic techniques are a valuable alternative when making inferences about potential viral infectivity, as they avoid laborious cell culture techniques and not all viruses can replicate in cell culture [27] . HAdV serotypes that are responsible for gastroenteritis are HAdV40 and 41 that are usually difficult to propagate in cell culture, so the use of enzyme tests can infer on viral infectivity, being a less laborious than techniques in cell culture [28] . Molecular and bioinformatics studies have both demonstrated higher efficiency in characterization, as in the discovery of new virus subtypes [29, 30] . HAdV-2 is commonly found throughout the world. The virus subtype causes diseases that affect the upper respiratory tract, particularly in children [31, 32] . The results of the HAdV characterization performed in the present study, by sequencing and molecular characterization, indicated the prevalence of HAdV, serotype subgroup C in the samples evaluated. The viruses that belong to HAdV subgroup C (C1-C2-C5-C6, and C7) are known to cause respiratory viral infections [33] . Our findings corroborate those of other studies that reported the prevalence of HAdV-2 in the aquatic environment and in stool samples [34] [35] [36] . Taken together, these studies and others indicate that HAdV-2 is one of the serotypes most commonly excreted by humans [37] , suggesting that this virus is intermittently excreted in the feces of most individuals, even if they are asymptomatic [16] .