Dear Editor,
In 2007, Allander et al. from the Karolinska Institute, discovered a new human polyomavirus (KIPyV) in respiratory secretions from patients with acute respiratory tract infections (ARTIs).1 Furthermore, Gaynor et al. from Washington University, reported in the same year another new polyomavirus (WUPyV) in respiratory secretions.2 The prevalence of these viruses range from 0% to 8% for KIPyV and from 0% to 1% for WUPyV depending on the age and immune status of the study population.1, 2, 3, 4, 5, 6
We determined the prevalence of KIPyV and WUPyV in a group of Dutch adult patients admitted to the hospital with community acquired pneumonia (CAP).
A throat swab was collected from 567 adult patients with suspected CAP admitted to the emergency ward of our hospital between March 2008 and March 2009. Patients’ ages ranged from 20 to 95 years (mean: 66.83 years; median: 69 years) and 59% were male.
Nucleic acids were extracted using the MagNa pure LC total nucleic acid isolation (Roche Diagnostics, Basel, Switzerland) and samples were tested for the presence of common respiratory viruses by real-time PCR specific for adenovirus, human bocavirus, human metapneumovirus, human rhinovirus, human coronaviruses (OC43, NL63, HKU, 229E), parainfluenza viruses 1–4, influenza A and B viruses, respiratory syncytial virus, and KIPyV and WUPyV.1, 2, 7, 8, 9
KIPyV was detected in 3 patients (0.5%) and WUPyV in 4 patients (0.7%), respectively, in both males and females. The ages of the KIPyV-positive and WUPy-positive patients ranged from 69 to 82 years (Table 1 ). Two KIPyV-positive patients had a respiratory syncytial virus or influenza B virus co-infection. Two WUPyV-positive patients had a co-infection, one with coronavirus NL63 and influenza B virus, and another with influenza A virus. One KIPyV- and one WUPyV-positive patient had a positive sputum culture for Haemophilus influenzae. None of the polyomavirus positive patients had positive bacterial or fungal blood cultures. Most (5/7) patients with KIPyV and WUPyV had underlying medical conditions. One patient had COPD and breast cancer, one patient had COPD and used immunosuppressive medication, 2 patients suffered from cardiac failure, 1 patient suffered from cardiac failure and diabetes.
Table 1.
Characteristics of KIPyV and WUPyV positive patients.
| Sex | Age | Month detected | Signs/symptoms | Co-infections | |
|---|---|---|---|---|---|
| KIPyV positive | |||||
| 1 | Male | 80 | December 2008 | Fever | Respiratory syncytial virus and Haemophilus influenzae |
| 2 | Female | 75 | January 2009 | Cough, fever, headache | None |
| 3 | Male | 82 | March 2009 | Cough, fever, dyspnoea | Influenza B virus |
| WUPyV positive | |||||
| 1 | Female | 84 | May 2008 | Cough | None |
| 2 | Male | 71 | September 2008 | Cough, fever, dyspnoea | Coronavirus NL63 and Influenza B virus |
| 3 | Male | 91 | January 2009 | Cough, fever, dyspnoea | None |
| 4 | Female | 69 | February 2009 | Cough, fever, dyspnoea | Influenza A virus and Haemophilus influenzae |
Similar to earlier reports we found KIPyV and WUPyV in small percentages of patients (<1%) and co-infections for KIPyV and WUPyV were detected in most of them.2, 3, 4, 5, 6 Given the fact that only 10% of CAP in The Netherlands is hospitalised, we have no data on the majority of patients who recovered at home. In this study KIPyV and WUPyV seem to infect adults (>69 years). Ren et al.5 did not found any WUPyV and KUPyV in nasal and throat swabs of immunocompetent adults. Abedi Kiasari et al.6 found 3 of 47 nasopharyngeal aspirates positive for KIPyV (6.3%) of adults aged between 45 and 69 and none positive for WUPyV. Mourez et al.4 found in nasal aspirates and bronchoalveolar lavages a prevalence of KIPyV of 8% in their population of immunocompromised patients (median age 46 years; range 3–85 years) and a prevalence of 1% of WUPyV.
In the literature KIPyV and WUPyV were detected throughout the year although seasonal variations were detected.2, 3, 10 In this study, with limited numbers of positive patients, no seasonality was observed.
Samples were collected using throat swabs in this study. As the sensitivity of our diagnostic PCR assay may be lower if throat swabs are used compared to sputum, nasopharyngeal sampling or washings, it is possible that we underestimate the prevalence of KIPyV and WUPyV in our population.11
In conclusion, KIPyV and WUPyV are incidentally present in adults with community acquired pneumonia. They are more often found in patients with an underlying medical condition. Finally, co-infections with KIPyV and WUPyV with other respiratory viruses are common.
Conflict of interest
None.
References
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