Viral causes of influenza‐like illness: Insight from a study during the winters 2004–2007

Abstract

Limited information is available on the viral etiology of influenza-like illness in southern European countries, and it is still a matter of debate whether certain symptoms can be used to distinguish among the specific viruses that cause influenza-like illness. The main objective of the present study was to identify the demographic and clinical predictors of influenza-like illness due to specific viral agents. The study, which was observational in design, was conducted in Rome and Naples, Italy. Cases of influenza-like illness were defined as individuals with fever >37.5 degrees C and at least one systemic and one respiratory symptom, recruited during the winters of 2004-2005, 2005-2006, and 2006-2007. Influenza and other respiratory viruses were identified using the polymerase chain reaction (PCR), performed on throat swabs. Basic individual information was collected using a standard form. A total of 580 persons were included in the analysis. Viral pathogens were identified in fewer than 50% of the cases. Overall, 240 viral agents were detected: 22.8% were positive for influenza viruses, 10.9% for adenoviruses, 6.0% for parainfluenza viruses, and 1.7% for respiratory syncytial virus. The month of diagnosis, and muscle and joint pain were associated with influenza virus, though the positive predictive value (PPV) was low. Abdominal pain was associated with adenovirus infection. Although the PPV of symptoms for influenza virus infection was low, especially in low activity periods, these findings may help clinicians to improve their ability to perform diagnoses.

Virological Diagnosis of Influenza Viruses in Zagazig University Hospitals

“…Concerning the clinical presentations of influenza virus infections fever (88.5%) and cough (84.6%) were the most common presenting symptoms followed by Rhinorrhra (76.9%) and whereas GIT symptoms appeared as uncommon clinical finding (7.7%). This was in agreement with Puzelli et al [26] & Ohmit and Monto [28] who reported that fever and cough are the best predictors for influenza virus infections. Fifteen (57.7%) of positive cases for influenza virus infection occurred in winter with peak in January 2011 [16,26].…”

“…This may be attributed to that school-age children have the highest contact rates and they have less immunity to influenza than adults and tend to excrete large amounts of virus. Another explanation of this age distribution is the higher vaccination coverage among older adults or the duration of viral shedding in young children which is usually longer than in adults and characterized by higher virus concentration [26]. Also sample collection may be more difficult in adults than in children since adults may resist more strongly the taking of swabs or blow their noses more often and thereby reduce the quantity of virus in the nasopharyngeal swab [27].…”

Etiology and Incidence of Viral Acute Respiratory Infections Among Refugees Aged 5 Years and Older in Hagadera Camp, Dadaab, Kenya

“…Among patients with ARI, muscle/joint pain was associated with influenza A, whereas headache was positively associated with influenza B. One previous study by Puzelli and others 13 demonstrated the similar association between muscle/joint pains and headache and influenza infection. However, another study by Yang X and others, Beijing failed to demonstrate that muscle/joint pains or headache were associated with influenza virus.…”

Chlamydophila pneumoniae, Mycoplasma pneumoniae, and influenza in children with respiratory infections in Alexandria, Egypt

“…First of all, the identification of the cause of ARI remains challenging, due either to inadequate samples that may lead to false negative results, or to difficult interpretation of positive findings between infection and colonization. Secondly, the low proportion of cases attributable to influenza viruses might be explained by the place of recruitment, since influenza is usually underrepresented in hospital-based studies [14]. In a previous study conducted in the same site, the respiratory syncytial virus was detected in 7% of the samples, representing 8% of all isolates, compared with 5% for influenza [9].…”