What is Rhinovirus? How Does the Rhinovirus Test Kit Work?
With three species and around 160 recognized serotypes, rhinoviruses are the most common viruses affecting human health and are among the primary causes of the common cold. Especially for those at higher risk of developing severe disease from airway infections, getting better informed on rhinoviruses along with available testing methods, vaccination, treatment, and prevention methods can be valuable. Read along to learn more about rhinoviruses, symptoms to look out for, different methods of testing, and how to protect yourself this winter season.
What are Rhinoviruses?
Rhinoviruses are small, non-enveloped, simple, positive-stranded RNA viruses that are members of the genus Enterovirus of the family Picornaviridae. Rhinoviruses are categorized into three species which are A, B, and C, with more than 160 known serotypes that differ according to their surface antigens. Unfortunately, immunity across different serotypes is very limited. In fact, infection-induced immunity against rhinoviruses is not only serotype-specific but also short-lived, and highly variable.
Rhinoviruses often spread from person to person through respiratory droplets, airborne aerosols, direct person-to-person contact, and contact with contaminated surfaces. Given the ability of rhinoviruses to survive on different objects and surfaces for a prolonged amount of time, transmission via hands and contaminated surfaces has been identified as a significant factor contributing to the spread of the disease. The incubation period of rhinovirus infections typically lasts 2 to 7 days, but infected people are known to shed the virus for up to six weeks.
What are the symptoms of a Rhinovirus infection?
Rhinoviruses are the most common etiologic agent of acute nasopharyngitis or the common cold. In fact, it is estimated that rhinoviruses are responsible for around 30-35% of all adult colds. The common cold is a mild and often self-limiting disease of the upper respiratory tract. Rhinoviruses primarily affect the nose and nasopharynx. The infection does not usually extend beyond the respiratory tract epithelium but can sometimes cause lower respiratory infections. Common symptoms of rhinovirus infections include runny nose, nasal congestion, sneezing, sore throat, and cough, which can be accompanied by myalgia, fatigue, headaches, and loss of appetite.
While rhinoviruses seldom cause severe illness, their role in acute exacerbations of asthma, chronic obstructive pulmonary disease, and other respiratory diseases has been observed. Thus, especially in patients with low or compromised immunities, other infections, and medical conditions, infection with rhinoviruses is more likely to cause severe disease and complications. As such, infants, older adults, and those with chronic asthma or other respiratory diseases are most affected by rhinovirus infections. In addition to exacerbations of reactive airway diseases, potential complications of rhinovirus infections may emerge from the spread of the infection from the nose and throat to the sinuses, the lower respiratory tract, and the middle ear, which may lead to sinusitis, laryngitis, chronic bronchitis, and otitis.
Are Rhinovirus infections common?
Rhinoviruses are the most common viruses affecting human health and are the predominant cause of the common cold around the world. Rhinoviruses are distributed worldwide, and multiple serotypes of rhinoviruses have been known to circulate simultaneously within a single community. Infection is common all year round but may lead to epidemics in autumn and spring. In fact, rhinoviruses are the primary cause of acute viral respiratory infections for the majority of the year. According to Monto (2002), rhinoviruses account for more than three-quarters of all viruses in circulation. Depending on the seasonal pattern of the specific year and geographic characteristics, rhinovirus infections can even be more predominant in spring. While respiratory infections are lower in warmer seasons, rhinoviruses also prove to be the most commonly isolated viruses during summer months. In the winter months, however, other respiratory viruses such as influenza, respiratory syncytial virus (RSV), and the more recent SARS-CoV-2 are known to predominate the circulation of rhinoviruses. However, similar to other respiratory viruses, the seasonal pattern of rhinoviruses is significantly affected by human factors such as the start of the school year and the holiday seasons.
How can you test for Rhinoviruses?
The diagnosis of rhinovirus infections usually involves a physical exam and the examination of medical history. However, as various common viruses, such as coronaviruses, adenoviruses, and parainfluenza viruses, can cause symptoms and complications similar symptoms and complications, testing may be required for the differential diagnosis in patients with severe disease and complications. In addition to the isolation of the virus in sensitive cell culture, infections with rhinoviruses can also be diagnosed and verified through antigen detection and nucleic acid detection methods. Among nucleic-acid detection methods, RT-PCR is the standard method for the detection of rhinoviruses in the laboratory. RT-PCR offers a faster and simpler method in comparison to virus isolation through cell culture. It also remains susceptible since the RNA sequences targeted by RT-PCR tests are almost entirely conserved among the majority of the serotypes. However, the results of these tests may be challenging to interpret as they are often positive for prolonged periods of time, even in asymptomatic individuals. On the other hand, antigen tests allow for point-of-care testing without the need for laboratory equipment or highly trained staff and deliver results in minutes. Although antigen testing is relatively less sensitive than virus isolation methods and nucleic acid detection methods, its convenience, accessibility, and affordability offer unique advantages for public health purposes.
How can you protect yourself against infections with Rhinoviruses?
Due to the limited level of cross-protection among its serotypes, there are currently no vaccines against rhinoviruses. However, recent studies have detected that some areas of the Rhinovirus genome were conserved among its different serotypes, which have demonstrated potential for the future development of a pan-serotype rhinovirus vaccine. A recent study by Lee et al. (2016) has proven that a polyvalent inactivated rhinovirus vaccine was broadly immunogenic in rhesus macaques, which has further accelerated the efforts for the development of a vaccine. In addition, washing hands regularly with soap and water, wearing masks around infected people, and refraining from touching the mouth, eyes, and nose can help prevent infection.
Monto, A. S. (2002). The seasonality of rhinovirus infections and its implications for clinical recognition. Clinical Therapeutics, 24(12), 1987–1997. https://doi.org/10.1016/s0149-2918(02)80093-5
Lee, S., Nguyen, M. T., Currier, M. G., Jenkins, J. B., Strobert, E. A., Kajon, A. E., Madan-Lala, R., Bochkov, Y. A., Gern, J. E., Roy, K., Lu, X., Erdman, D. D., Spearman, P., & Moore, M. L. (2016). A polyvalent inactivated rhinovirus vaccine is broadly immunogenic in rhesus macaques. Nature Communications, 7(1). https://doi.org/10.1038/ncomms12838
Khan, M. U., Farman, A., Rehman, A. U., Israr, N., Ali, M. Z. H., & Gulshan, Z. A. (2021b). Automated System Design for Classification of Chronic Lung Viruses using Non-Linear Dynamic System Features and K-Nearest Neighbour. 2021 Mohammad Ali Jinnah University International Conference on Computing (MAJICC). https://doi.org/10.1109/majicc53071.2021.9526272