Influenza A Virus and the Test Way

Influenza ( short for influenza) is a common acute respiratory infectious disease caused by influenza virus, common in winter and spring. It is also a highly contagious and rapidly spreading disease. It is mainly transmitted through airborne droplets, person-to-person contact or contact with contaminated objects.

Influenza viruses belong to the orthomyxoviridae family. They are 80-120nm in diameter, spherical or filamentous, and have an RNA virus genome. There are three types of influenza viruses: influenza A (A), influenza B (B) and influenza C (C). Among them, A is particularly prone to mutation and can infect humans and a variety of animals. It is the main pathogen of human influenza, often causing pandemic and small and medium-sized epidemics. Influenza B viruses mutate less and cause outbreaks or mini-epidemics. The influenza C is stable and can infect humans, mostly in sporadic cases.

The influenza A and norovirus infections, which account for 99% of seasonal flu cases, are in high season. Even more contagious and lethal than COVID-19. This influenza is mainly A(H1N1). The surveillance data of the National Influenza Center showed that the positive rate of influenza virus detection continued to rise in the seventh week of 2023 (February 13-19) in southern and northern provinces, with A(H1N1)pdm09 predominating and A(H3N2) subtype influenza viruses circulating together. The percentage of influenza-like cases in southern and northern provinces increased slightly. Generally speaking, influenza A is much more prevalent than influenza B. As far as the current detection data, the domestic influenza A accounted for 99.2%, B accounted for 0.8%.

In retrospect, there have been four influenza pandemics, named 1918 H1N1, 1957 H2N2, 1968 H3N2, and 2009 H1N1 [1]. Up to now, about 1 billion people around the world are infected with influenza virus every year, and 294 000~518 000 people die from seasonal influenza [2].

2 The symptoms of the influenza A virus infection

The incubation period of the influenza A is usually 1-3 days. Clinically, it is characterized by severe systemic poisoning symptoms such as high fever, fatigue, headache, and body pain, while respiratory symptoms are relatively light. There are also some mild respiratory symptoms, such as cough, runny nose, sore throat, etc. Influenza virus is prone to mutation, strong infectivity, often cause influenza epidemic.

Both influenza A virus and novel coronavirus are respiratory diseases. They have similar symptoms of infection, including fever, headache, myalgia and discomfort. However, the pathogens and epidemiological characteristics of the two viruses are quite different.

3 How to treat the influenza A virus infection.

Until now, influenza vaccines have been mainly divided into two types: live attenuated nasal spray vaccine (trivalent) and inactivated influenza vaccine (trivalent or quadvalent). The nasal spray vaccine is suitable for children aged 3-17 years. The trivalent vaccine is available in child form (0.25ml) and adult form (0.5ml). A new change for this year’s flu vaccine is that children aged 6-35 months can receive the quadrivalent inactivated vaccine (0.25ml).

In terms of coverage, inactivated tetrad > inactivated triad > nasal spray triad, and in terms of price, nasal spray triad > inactivated tetrad > inactivated triad. From the perspective of vaccine effectiveness, there was little difference among brands of inactivated vaccines, and the data of nasal spray attenuated live vaccines in children group was slightly better. Flu shots must be given before flu season, usually between October and December.

Oseltamivir is not an anti-flu drug, but it is not completely ineffective or has significant side effects. It is not recommended to blindly stock up, it is not recommended to use it for excessive treatment and prevention, nor is it recommended to blindly reject its use. For individuals, getting an annual flu vaccine is the best form of prevention. For now, oseltamivir remains the drug of choice for antiviral treatment against influenza, after being evaluated and weighed by a doctor.

At present, the commonly used detection methods of the influenza A detection reagents on the market are: PCR- fluorescence probe method and colloidal gold immunochromatography. East- Mab Biomedical can provide high-quality raw materials of influenza A antibodies, we have perfect quality control system and affordable price.Of course you can check them with free sample at first.

Raw materials for testing Influenza A virus

Reference

[1] Wang Dayan, Shu Yuelong. The history and thinking of influenza pandemic [J]. Science in China: Life Sciences,2018,48(12): 1247-1251.

[2] PAGET J,SPREEUWENBERG P,CHARU V,et al.Global mortality associated with seasonal influenza epidemics: new burden estimates and predictors from the GLaMOR project [J].J Glob Health,2019,9(2):020421.