Respiratory tract infections

Infections in respiratory tract are one of the most common reasons why people visit healthcare professionals¹. However, as the symptoms and signs of influenza, COVID-19 and other respiratory infections somewhat overlap, the correct diagnosis of the infection is critical. A swift diagnosis ensures the right treatment and minimal spread of the infection. Correct diagnosis also reduces unnecessary antibiotic prescribing. Aidian offers a wide range of visually read and instrument read rapid tests for the detection of influenza, SARS-CoV-2, and other respiratory infections.

C-reactive protein (CRP) 

Accurate and rapid CRP point of care testing aids in the clinical management of patients with symptoms of infection. Measuring CRP increases diagnostic certainty, guides appropriate antibiotic prescribing and aids in ruling out severe bacterial infections^2-4.

Learn more:

About C-reactive protein (CRP)

CRP and lower respiratory tract infections

Bacteria

Bacteria are microscopic single-celled organisms that can live inside or outside a body. Different bacteria play a vital role in human health – they live on our skin and in our bodies playing a role for example in digesting food. However, bacteria can also cause infectious diseases.⁵ Unlike viral infections, certain bacterial infections can be treated with antibiotics⁶. 

Bacteria can be divided into Gram-negative and Gram-positive bacteria. Gram-negative bacteria have an extra outer membrane which makes it harder for antibiotics to penetrate through. Gram-negative bacteria are also more prone to developing resistance towards antibiotics.⁵

Bacteria causing respiratory tract infections 

Bacteria can cause several respiratory infections including for example pharyngitis, pneumonia, and acute bronchitis. Rapid diagnostic testing improves the management of respiratory infections and guides appropriate antibiotic use. Avoiding unnecessary antibiotic use is important in combatting antibiotic resistance⁶. 

Below are some examples of bacteria causing respiratory tract infections and products that can be used in their diagnostics.

Streptococcus pyogenes 

S. pyogenes, also called Strep A or GAS, is a significant cause of pharyngitis. Streptococcal pharyngitis is often difficult to distinguish from viral infection⁷ and rapid tests offer fast and cost-effective way to detect Strep A infections accurately.

Products:

• QuikRead go Strep A (used together with the QuikRead go Instrument / QuikRead go Plus Instrument)

Legionella

Legionella may cause a serious type of pneumonia. The bacteria can grow in freshwater systems and spread through small droplets. Less commonly people can get sick also by aspiration of drinking water containing Legionella.⁸ Rapid test detects the Legionella antigens in urine specimens.

Mycoplasma pneumoniae

M. pneumoniae is a bacterium that is causing usually mild but long-lasting infections of the respiratory system. The most common type of illness caused by M. pneumoniae is tracheobronchitis, but it can also cause pneumonia⁹. Mycoplasma rapid tests detect the M. pneumoniae immunoglobulin M (IgM) antibody in serum samples.

Streptococcus pneumoniae

S. pneumoniae is often found in respiratory tract of healthy persons, especially the ones having school-aged children or persons in military settings¹⁰. Pneumonia, bacteremia and meningitis caused by S. pneumoniae most often occurs when predisposing condition exists.

Viruses

Viruses are not cells and, unlike cells, viruses have no metabolic abilities of their own¹¹. To be able to survive and reproduce, viruses need to enter a living cell (such as a human cell) called a host⁵.

Infections caused by viruses can’t be treated with antibiotics. For some viral infections there are antiviral drugs available but antibiotics do not work on viruses^6,12. Taking antibiotics when they’re not needed does not offer any help. On the contrary, unnecessary antibiotic use could cause harmful side effects and it contributes to the rise of antibiotic resistance^5,6.

Viruses causing respiratory tract infections

Viruses can cause several respiratory tract infections including for example influenza, COVID-19, and RSV infection. Correct diagnosis of viral infection reduces unnecessary antibiotic use. 

Below are some examples of viruses causing respiratory tract infections and products that can be used in their diagnostics.

Adenovirus

Adenovirus can cause illnesses from common cold to sore throat, but it can also cause pneumonia, acute gastroenteritis, and neurological diseases¹³. Adenovirus rapid tests help to identify the cause of the symptoms as the symptoms of respiratory adenoviral infection may be difficult to differentiate from other respiratory infections.

Respiratory syncytial virus (RSV) 

RSV is a leading cause of respiratory tract infections and it accounts for more than 60% of acute respiratory tract infection cases among young children^14,15. RSV is often associated with high morbidity and mortality rates among children as well as the elderly and immunocompromised patients. As the symptoms are very similar to other viral infections, RSV rapid tests assist in detection of the cause of the illness.

Infectious mononucleosis

Infectious mononucleosis Infectious mononucleosis is a contagious disease usually caused by Epstein-Barr virus (EBV) and it is common among teenagers and young adults¹⁶. With rapid mononucleosis test, EBV can easily be detected from whole blood, fingerstick whole blood, serum or plasma.

Influenza

Influenza is one of the leading causes of acute respiratory infections¹⁷. Despite the seasonal vaccination against influenza, the infections represent a considerable public burden worldwide. This is due to continuous antigen changes in the surface glycoproteins of influenza virus, which reduce the effectiveness of vaccination¹⁸. Influenza rapid tests help to quickly differentiate the cause of the illness making it easier to treat the patients accurately.

SARS-CoV-2

COVID-19 is the respiratory disease caused by SARS-CoV-2. People infected with SARS-CoV-2 will experience mild to moderate respiratory illness and most will recover without a need for special treatment. However, COVID-19 can sometimes cause a severe disease requiring intensive care. Older people and those with underlying medical conditions are more likely to develop serious illness.¹⁹ COVID-19 can transmit easily, and rapid identification of infected persons aids in cutting transmission routes.

References

1. Finely CR, Chan DS, Garrison S, et al. What are the most common conditions in primary care? Canadian Family Physician 2018; 64, 832-840.
2. Markanday A. Acute Phase Reactants in Infections: Evidence-Based Review and a Guide for Clinicians. Open Forum Infect Dis 2015; 2(3): ofv098.
3. Little P et al. Effects of internet-based training on antibiotic prescribing rates for acute respiratory-tract infections: a multinational, cluster, randomised, factorial, controlled trial. Lancet 2013; 382(9899): 1175-1182.
4. Emery P. Evidence-based review of biologic markers as indicators of disease progression and remission in rheumatoid arthritis. Rheumatol Int 2007; 27(9): 793-806.
5. What’s the difference between bacteria and viruses? https://imb.uq.edu.au/article/2020/04/difference-between-bacteria-and-viruses Accessed: 3 March 2026
6. Centres for Disease Control and Prevention (CDC). Antibiotic Do’s & Don’ts. https://www.cdc.gov/antibiotic-use/do-and-dont.html Accessed: 14 December 2023
7. Bisno AL, Gerber MA, Gwaltney JM Jr, Kaplan EL, Schwartz RH. Practise Guidelines for the Diagnosis and Management of Group A Streptococcal Pharyngitis. CID 2002; 35(2); 113 - 125.
8. Centres for Disease Control and Prevention (CDC). About the Disease. Available at: https://www.cdc.gov/legionella/about/index.html Accessed: 3 March 2026
9. Centres for Disease Control and Prevention (CDC). Signs and Symptoms. Available at: https://www.cdc.gov/pneumonia/atypical/mycoplasma/about/signs-symptoms.html Accessed: 9 October 2023
10. Centres for Disease Control and Prevention (CDC). Streptococcus pneumoniae. Available at: https://www.cdc.gov/pneumococcal/clinicians/streptococcus-pneumoniae.html Accessed: 9 October 2023
11. Michael T. Madigan, John M. Martinko, Jack Parker. Brock Biology of Microorganisms (10th Edition). Pearson Education Inc, 2003.
12. Centres for Disease Control and Prevention (CDC). Viruses or Bacteria; What’s got you sick? https://www.cdc.gov/antibiotic-use/pdfs/VirusOrBacteria-Original-P.pdf Accessed: 3 March 2026
13. Centres for Disease Control and Prevention (CDC). Symptoms. Available at: https://www.cdc.gov/adenovirus/symptoms.html Accessed: 5 October 2023.
14. Hall CB. Respiratory syncytial virus and parainfluenza virus. N Engl J Med. 2001;344(25):1917–28.
15. Falsey AR, Hennessey PA, Formica MA, Cox C, Walsh EE. Respiratory syncytial virus infection in elderly and high-risk adults. N Engl J Med. 2005;352(17):1749–59.
16. Centres for Disease Control and Prevention (CDC). About Infectious Mononucleosis. Available at: https://www.cdc.gov/epstein-barr/about-mono.html Accessed: 5 October 2023.
17. Reed C, Chaves SS, Kirley PD, et al. Estimating influenza disease burden from population-based surveillance data in the United States. PLoS ONE 2015;10:e0118369.
18. de Vries RD, Altenburg AF, Rimmelzwaan GF. Universal influenza vaccines: A realistic option? Clinical Microbiology and Infection 2016;22:S120-S4.
19. European Centre for Disease Prevention and Control (ECDC). Questions and answers on COVID-19: Basic facts. Available at: https://www.ecdc.europa.eu/en/covid-19/questions-answers/questions-answers-basic-facts Accessed: 3 March 2026