As the respiratory tract is one of the three significant conduits between the human body and the outside world, many pathogens from the outside world can easily enter the respiratory tract and cause the occurrence of many diseases. These diseases are characterized by high susceptibility, rapid transmission, and are difficult to control. Data from the World Health Organization prior to COVID-19 pandemic showed that respiratory infections and other diseases caused by them ranked as the third leading cause of human death.
The most common infections of the respiratory tract are caused by viruses. COVID-19 sweeping the world has seriously challenged the global healthcare system and has become the absolute protagonist in the field of respiratory infections today. The most common respiratory viruses are coronaviruses, influenza viruses, syncytial viruses, rhinoviruses, parainfluenza viruses, and adenoviruses.
We have developed a number of panels for common respiratory viruses based on PCR and multiplex PCR technology for a wide range of samples. They provide fast, accurate and reliable results with simultaneous detection of mutations and subtypes.
In addition to our respiratory virus PCR panels, we offer a range of analytical and PCR sequencing services.
Polymerase chain reaction (PCR) detection for respiratory pathogens is easy, fast, accurate, and early detection. Compared to other testing methods such as antibodies, PCR technology is highly sensitive, and can detect pathogens as long as they are present in the body, even in trace amounts. Moreover, the sampling is convenient, and the detection of six pathogens can be done in one sampling. In addition, the nucleic acid test uses a probe method with high specificity (simply understood: the proportion of non-genuine cases is correctly identified) and accurate and reliable test results.
PCR technology has the following three applications in respiratory virus research.
Coronavirus mainly invades the respiratory and digestive tracts and can involve the nervous system. Coronaviruses are the most predominant pathogens of respiratory infections, accounting for approximately 15%-30% of the causative agent of the common cold. In recent decades, more than half of the major global infectious disease outbreaks have also been associated with these viruses, with SARS, MERS, and COVID-19 outbreaks being caused by these viruses, and every few years a newly discovered coronavirus stirs the nerves of epidemic prevention worldwide.
Severe Acute Respiratory Syndrome (SARS), a respiratory disease caused by a novel coronavirus outbreak in 2003, occurred mainly in East Asia and caused more than 8,000 infections and 774 deaths over the course of a year. The widespread use of hormonal modulation of immunity has reduced the mortality rate to some extent, but the mortality rate of about 10% is still high for respiratory viral infections.
Middle East respiratory syndrome, which broke out in the Middle East in 2012, is also a category of rapid and severe respiratory symptoms caused by MERS-CoV that has a faster onset and higher criticality than other coronavirus infections, and can migrate to the urinary system, causing dual system failure of respiratory failure and renal failure, so the rate of death is extremely high for people with underlying disease. By September 2015, there were 1569 cumulative cases and 703 deaths worldwide, with a 45% morbidity and mortality rate, ranking high as the leading respiratory virus mortality rate.
A viral infectious respiratory disease that is widely circulating worldwide in 2019. It is caused by a novel coronavirus (SARS-CoV-2), and the main sites of infection are the lower respiratory tract and lungs. As of August 13, 2021, it has caused 200 million infections and 4.3 million deaths worldwide, with a morbidity and mortality rate of 2.1%. In terms of morbidity and mortality, it is lower than SARS and MERS. However, the transmission rate is extremely high and widespread, and as a global epidemic, it can be ranked in the top 5 in the history of global infectious diseases, and in the field of respiratory infectious diseases, it is second only to the influenza pandemic in Europe and the United States in the 1910s.
Influenza viruses include human and animal influenza viruses. Human influenza viruses are divided into three types: A, B, and C, which are the pathogens of influenza (flu). Among them, influenza A virus antigenicity is prone to mutation and has caused many worldwide pandemics. For example, in the pandemic of 1918-1919, at least 20-40 million people died of influenza worldwide; influenza B virus is also more pathogenic to humans, but it has not been found that influenza B virus has caused a worldwide pandemic; influenza C virus only causes inconspicuous or mild upper respiratory tract infections in humans and rarely causes pandemics.
On the basis of nucleoprotein antigenicity, influenza viruses are also classified into different subtypes based on the antigenicity of hemagglutinin HA and neuraminidase NA. HA can be divided into 18 subtypes and NA into 11 subtypes, and different combinations of the two form different influenza subtypes. Genetic recombination, antigenic drift, and antigenic transformation cause viral mutation, and the continuous emergence of new viral strains is the main reason why influenza appears every year according to the season.
Influenza A virus is the most common and pathogenic influenza virus, which not only has numerous subtypes and numerous mutated strains, but also covers strains of human and animal commensal influenza such as avian influenza and swine influenza, therefore, the influenza flow adjustment, treatment and vaccine are basically for Influenza A virus.
Influenza B virus causes pandemic influenza, which is characterized by rapid onset and high contagiousness, symptoms and response plan (detection, treatment, prevention and control) are similar to those of influenza A, but the rate of severe illness and death is lower than that of influenza A. The frequency of antigenic transformation is lower than that of influenza A, so the vaccine against influenza B has a longer duration of action than that of influenza A. For influenza B virus, we generally refer to influenza A virus and combine the management, diagnosis, treatment and prevention of both.
Influenza C virus only causes mild upper respiratory symptoms, so there are no strict control measures or targeted treatment plans for it, but only the same treatment plan as for rhinovirus, adenovirus and other common cold pathogens.
In recent years, influenza in animals is breaking through the racial barrier and receptor specificity and is mutating into a human-animal co-morbid disease. In 2013, the H7N9 avian influenza virus caused an epidemic in China. The result was more than 130 infections and 45 deaths.
These include syncytial viruses, parainfluenza viruses, rhinoviruses, adenoviruses, human parapneumoviruses, and Boca viruses.
These viruses do not cause severe, global, high morbidity and mortality epidemics compared to coronaviruses and influenza viruses, but they are also pathogens that are dangerous to human health. Some of them are long-term latent in the human respiratory tract and are resident viruses that cause the common cold when the human immune system is low, and normal adults usually carry such viruses without causing disease due to the immune system. However, this type of virus has a greater chance of causing disease in people with low immunity.
