Human Rhinoviruses: the Forgotten but Still Important Viruses

Human rhinoviruses (HRVs) are responsible for many of the characteristic symptoms of the common cold, such as a sore throat, runny nose, nasal congestion, sneezing, and coughing. However, despite the high detection rate in children, most HRV infections are asymptomatic. As a result, these viruses are generally ignored, even though a close association between HRV infections in early life and the subsequent induction of asthma has been reported. Therefore, it is necessary to conduct further research into HRV diagnostics, treatments, epidemiology, and vaccines. This review describes recent studies of HRVs, including their genomic diversity, surveillance systems, taxonomy, and immune responses, as well as vaccines.

Human Rhinoviruses: the Forgotten but Still Important Viruses

Human rhinoviruses (HRVs) are responsible for many of the characteristic symptoms of the common cold, such as a sore throat, runny nose, nasal congestion, sneezing, and coughing. However, despite the high detection rate in children, most HRV infections are asymptomatic. As a result, these viruses are generally ignored, even though a close association between HRV infections in early life and the subsequent induction of asthma has been reported. Therefore, it is necessary to conduct further research into HRV diagnostics, treatments, epidemiology, and vaccines. This review describes recent studies of HRVs, including their genomic diversity, surveillance systems, taxonomy, and immune responses, as well as vaccines.

Rhinovirus detection by real-time RT-PCR in children with acute respiratory infection in Buenos Aires, Argentina / Detección de rinovirus por RT-PCR en tiempo real en muestras respiratorias de niños de Buenos Aires, Argentina

Human rhinoviruses (HRV), the major cause of common colds, have a significant genetic diversity and are classified into 3 species (A, B, C) with more than 100 serotypes. HRV species C, described in 2006, can only be detected using molecular methods. The objectives of this paper were to adapt a real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for HRV detection and to further determine the frequency of HRV in respiratory samples from children under 2 years of age, with acute respiratory infection (ARI), from Buenos Aires, Argentina. Two real-time RT-PCR assays amplifying the 207 base pair of the 5' non-coding region were compared. The original protocol includes locked nucleic acid analogues and a pyrimidine derivative in the forward primer, while the adapted protocol avoided those molecules. Of 67 respiratory samples, 17 (25.4 %) were positive with the original protocol, and 20 (29.9 %) with the adapted one. Discrepant results were confirmed by sequencing analysis. An expanded gold standard was defined to determine the performance of both assays, and was used to describe the clinical characteristics of positive patients. Better sensitivity and specificity were obtained with the adapted protocol. Considering the expanded gold standard, HRV were detected in 23/67 (34.3 %) patients with ARI: 8/18 (44.4%) outpatients and 15/49 (30.6 %) hospitalized. Wheezing episodes were more frequent in HRV positive patients (43.5 %) than in HRV negative patients (18.2 %) (p = 0.041). This study describes the utility and clinical sensitivity of an adapted real-time RT-PCR assay for HRV detection.

Los rinovirus humanos (RVH) constituyen la principal causa de resfrío común y poseen una gran diversidad genética, con más de 100 serotipos clasificados en tres especies (A, B, C). Los RVH C fueron descritos en 2006 y solo pueden detectarse utilizando métodos moleculares. El objetivo del presente trabajo fue adaptar un protocolo de transcripción reversa seguida de reacción en cadena de polimerasa (RT-PCR) en tiempo real para detectar RVH y posteriormente determinar su frecuencia en muestras de niños menores de 2 años con infección respiratoria aguda (IRA). Se compararon dos protocolos de RT-PCR en tiempo real, que amplifican 207 pares de bases de la región 5' no codificante. El protocolo original incluyó un cebador directo con análogos de nucleótidos bloqueados (LNA) y un derivado pirimidínico en su secuencia, mientras que el protocolo adaptado no los incluyó. De 67 muestras, 17 (25,4 %) fueron positivas con el protocolo original y 20 (29,9 %) con el protocolo adaptado; los resultados discrepantes se confirmaron por secuenciación. Se definió un gold standard expandido para determinar el desempeño de ambos ensayos y describir las características clínicas de los pacientes RVH positivos. La mejor sensibilidad y especificidad se obtuvo con el protocolo adaptado. Considerando el gold standard expandido, se detectó RVH en 23/67 (34,3 %) pacientes con IRA: 44,4 % (8/18) ambulatorios y 30,6 % (15/49) internados. Los episodios de sibilancias fueron más frecuentes en pacientes RVH positivos (43,5 %) que en RVH negativos (18,2 %) (p = 0,041). El presente estudio describe la utilidad y la sensibilidad clínica de esta RT-PCR en tiempo real adaptada para detectar RVH.

Human rhinovirus in the lower respiratory tract infections of young children and the possible involvement of a secondary respiratory viral agent

Human rhinoviruses (HRV) are usually associated with mild respiratory symptoms in children. However, some studies have found that HRV can cause severe disease, especially when the patient is co-infected with a second virus. In this study, 532 nasopharyngeal aspirates (NPAs) were collected over a nine-year period from children at the Clinics Hospital of Uberlândia. The collected NPAs were then tested for HRV RNA using the reverse transcription-polymerase chain reaction. Eighty-three specimens from children diagnosed with lower respiratory tract illness (LRTI) were positive for HRV RNA and were then tested for the presence of eight other respiratory viruses. A second virus was detected in 37.3 percent (31/83) of the samples. The most frequent clinical diagnosis was bronchiolitis, followed by other LRTI and then pneumonia. The frequency of severe disease in children infected with more than one virus was not significantly different from the frequency of severe disease in children infected with HRV alone. Children infected with both HRV and parainfluenza virus (1.5 m.o.) were significantly younger than those infected by HRV alone (5.0 m.o.) (p = 0.0454). Overall, these results suggest that infection with a second virus does not lead to a higher frequency of severe syndromes in children presenting with LRTI.