Introduction: Merkel cell polyomavirus is categorized as a member of the Polyomaviridae family, with a double-stranded DNA as its genomic material, which is associated with Merkel cell carcinoma and was first identified in 2008. Epidemiological studies have demonstrated a high seroprevalence of MCPyV in adults, particularly in the skin tissues of asymptomatic individuals.
In recent years, research has demonstrated that MCPyV is not only confined to human tissues but can also be identified in the environment, such as wastewater, surface water, and even swimming pools. The relative stability of MCPyV in water suggests the possibility of indirect transmission; as a result, it emphasizes the importance of monitoring water sources.
Since swimming pools are frequently used by humans, identifying and assessing the level of MCPyV contamination is of particular public health importance. Such studies can help to have a better understanding of the possible routes of viral transmission and also play a crucial role in improving healthcare quality.
This study aims to investigate the presence of MCPyV in recreational water samples from different pools located in Tehran, Iran.
Methods: The samples collected in favor of this study include 40 various swimming pools' water located in different geographical areas of Tehran. Physicochemical characteristics of the collected water samples were analyzed. The samples were concentrated using electronegative filters, and after extraction, they were processed by applying a nested PCR technique to detect and identify MCPyV. Three positive samples were sequenced, and phylogenetic analysis was performed to classify these samples.
Results: The results show that 14 out of 40 samples were positive (35%). No significant differences were found in Physicochemical characteristics, including temperature, PH, turbidity, free chlorine concentration, EC, and TDS, among MCPyV-positive and negative samples. The phylogenetic analysis revealed that the MCPyV isolates belonged to the Caucasian clade.
Conclusion: These results indicate that MCPyV can enter aquatic environments through human secretions, feces and urine, and is relatively persistent in these environments. This also highlights the importance of monitoring recreational water sources for the viral contamination. Given that the time this virus can persist in infected pool water or whether it can contribute to disease transmission is unclear, further studies on its persistence, viral load, and transmissibility are warranted.