The flu is an infection of the nose, throat, and lungs. It spreads easily from person to person. This article discusses influenza types A and B. A type of influenza A infection due to the H1N1 influenza strain is commonly called the swine flu. Alternative Names Influenza — commonly known as the flu — is a respiratory infection caused by flu viruses. There are three main types of influenza: A, B, and C. Types A and B are similar, but influenza B can ...The four main types of Type A and B influenza viruses that are most likely to spread and make people sick during the upcoming flu season are the targets of seasonal influenza (flu) vaccines. All of the available flu vaccinations in the United States offer protection against the influenza A(H1), A(H3), B/Yamagata, and B/Victoria lineage viruses.*The BD Veritor™ System for Rapid Detection of SARS-CoV-2 & Flu A+B is intended for the in vitro, simultaneous qualitative detection and differentiation of SARS-CoV-2 nucleocapsid antigen and/or influenza A and B nucleoprotein antigens directly from anterior nasal swab samples taken from individuals who are suspected of a viral respiratory infection consistent with COVID-19 by a healthcare ... Similarities: Both COVID-19 and flu can have varying degrees of symptoms, ranging from no symptoms (asymptomatic) to severe symptoms. Common symptoms that COVID-19 and flu share include: Fever or feeling feverish/having chills. Cough. Shortness of breath or difficulty breathing.Jan 12, 2023 · There are 4 types of influenza viruses, types A, B, C and D. Influenza A and B viruses circulate and cause seasonal epidemics of disease. Influenza A viruses are further classified into subtypes according to the combinations of the hemagglutinin (HA) and the neuraminidase (NA), the proteins on the surface of the virus. Currently circulating in ... Sep 28, 2022 · Similarities: Both COVID-19 and flu can have varying degrees of symptoms, ranging from no symptoms (asymptomatic) to severe symptoms. Common symptoms that COVID-19 and flu share include: Fever or feeling feverish/having chills. Cough. Shortness of breath or difficulty breathing. Oct 3, 2022 · fever* or feeling feverish/chills. cough. sore throat. runny or stuffy nose. muscle or body aches. headaches. fatigue (tiredness) some people may have vomiting and diarrhea, though this is more common in children than adults. *It’s important to note that not everyone with flu will have a fever. There are two main types of influenza viruses: types A and B. Both type A and B influenza viruses regularly spread in people and are responsible for seasonal flu each year. WHAT IS THE Follow recommended infection prevention and control measures1. SARS-CoV-2 Testing. Test for SARS-CoV-2 by nucleic acid detection 2. , 3 ; OR if not available, by SARS-CoV-2 antigen detection assay. 5. a) If SARS-CoV-2 Test result is positive, administer supportive care. If the patient is at high risk for progression to severe COVID-19 ...People who are sick with flu often feel some or all of these symptoms: Fever*/feeling feverish or chills. Cough. Sore throat. Runny or stuffy nose. Muscle or body aches. Headaches. Fatigue (tiredness) Some people may have vomiting and diarrhea, though this is more common in children than adults.Waner JL, Todd, SI, Shalaby H, et al. Comparison of Directigen FLU-A with viral isolation and direct immunofluorescence for the rapid detection and identification of influenza A virus. J Clin Microbiol. 1991; 29(3):479-482. 2037665serious flu complications. There are two main types of . influenza viruses: types A and B. Both type A and B . influenza viruses regularly spread in people, and are . responsible for seasonal flu ... Information for the 2023-2024 Flu Season Thursday, August 17, 2023. CDC Reports Two Human Infections with Flu Viruses From Pigs Friday, August 4, 2023. H5N1 Bird Flu Found in Polish Domestic Cats Friday, July 21, 2023. Influenza Risk Assessment Tool (IRAT) Thursday, July 6, 2023. Virus Descriptions and Report Summaries Tuesday, July 4, 2023.Influenza, commonly known as " the flu ", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms begin from one to four days after exposure to the virus (typically two days) and last for about 2–8 days.The flu is an infection of the nose, throat, and lungs. It spreads easily from person to person. This article discusses influenza types A and B. A type of influenza A infection due to the H1N1 influenza strain is commonly called the swine flu. Alternative NamesAs fears of a "tripledemic" die down, health officials say they are seeing an uptick of a particular strain of the flu: influenza B. According to data from the Centers for Disease Control and ...Influenza types A and B. These 2 types of viruses cause widespread illness (epidemics) almost every winter. They often lead to more people needing to go to the hospital, and more people dying from the flu. Public health officials focus on stopping the spread of types A and B. One of the reasons the flu remains a problem is because the viruses ... Mar 26, 2018 · Influenza — commonly known as the flu — is a respiratory infection caused by flu viruses. There are three main types of influenza: A, B, and C. Types A and B are similar, but influenza B can ... Print. The Centers for Disease Control and Prevention (CDC) recognizes that school administrators, teachers, staff, and parents are concerned about influenza (flu), particularly its effects on children. Educators and staff can help slow the spread of respiratory illnesses, including flu. On this page, you will find information on preventing the ...The influenza virus causes flu. Influenza A, B and C are the most common types that infect people. Influenza A and B are seasonal (most people get them in the winter) and have more severe symptoms. Influenza C doesn’t cause severe symptoms and it’s not seasonal — the number of cases stays about the same throughout the year. Interference was observed for flu A, flu B, RSV, and SARS-CoV-2 when evaluated with high concentrations of Pneumocystis jirovecii (PJP). There is a risk of false negative for flu A, B, RSV, and SARS-CoV-2 results under certain co-infection circumstances with Pneumocystis jirovecii (PJP). The Alinity m Resp-4-Plex assay was validated with ...During the 2020-2021 flu season, there was very low circulation of seasonal flu viruses. During September 27, 2020–May 22, 2021 in the United States, 1,899 (0.2%) of 1,081,671 clinical samples tested were positive for an influenza virus (713 [37.5%] influenza A and 1,186 [62.5%] influenza B). During that same period, public health ...People who are sick with flu often feel some or all of these symptoms: Fever*/feeling feverish or chills. Cough. Sore throat. Runny or stuffy nose. Muscle or body aches. Headaches. Fatigue (tiredness) Some people may have vomiting and diarrhea, though this is more common in children than adults.Influenza A and B: A(H1), A(H1)pdm09, A(H3) SARS-CoV-2, Adenovirus, Coronavirus 229E, Coronavirus HKU1, Coronavirus NL63, Coronavirus OC43, Human Metapneumovirus, Human Rhinovirus/Enterovirus, Parainfluenza Virus 1, Parainfluenza Virus 2, Parainfluenza Virus 3, Parainfluenza Virus 4, Respiratory Syncytial Virus: NPS: Approximately 45 minutes ...Waner JL, Todd, SI, Shalaby H, et al. Comparison of Directigen FLU-A with viral isolation and direct immunofluorescence for the rapid detection and identification of influenza A virus. J Clin Microbiol. 1991; 29(3):479-482. 2037665The four types of influenza are A, B, C, and D. Types A and B are widespread during most winters in the United States. Type C is milder than types A or B and does not spread as easily. Type D ...Influenza (flu) is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs. Some people, such as people 65 years and older, young children, and people with certain health conditions, are at higher risk of serious flu complications. There are two main types of influenza (flu) viruses: types A and B.Flu viruses are of four main types: A, B, C and D. Human influenza type A and B viruses are mainly responsible for the “flu season,” or seasonal influenza epidemics almost every winter in the United States. Type A influenza: This is the cause of most flu cases. It is the only influenza virus causing flu pandemics (a large number of flu ...Nationally, flu activity during the 2021-2022 season began to increase in November and remained elevated until mid-June with two different waves of influenza A (H3N2) virus activity occurring; the first peaked in late December 2021, and the second in April 2022. Prior to the emergence of SARS-CoV-2, flu activity would most commonly begin to ...Sep 28, 2022 · Similarities: Both COVID-19 and flu can have varying degrees of symptoms, ranging from no symptoms (asymptomatic) to severe symptoms. Common symptoms that COVID-19 and flu share include: Fever or feeling feverish/having chills. Cough. Shortness of breath or difficulty breathing. The last time the state saw a significant wave of influenza B was in 2019, when 12,950 cases of influenza B were recorded. In 2020, 720 notifications of influenza B were made. There were 57 in ...Feb 16, 2023 · indicate that influenza A and/or influenza B is likely, and diagnostic test results for other causes of illness (e.g., other respiratory illness) are negative. Rapid Molecular Assay [influenza viral RNA or nucleic acid detection] A and B. NP 5 swab, nasal swab. 15-30 minutes 6. Yes/No 6. Immunofluorescence, Direct (DFA) or Indirect (IFA) Florescent Antibody Staining [antigen detection] A and B. NP 4 swab or wash, bronchial wash, nasal or endotracheal aspirate. 1-4 hours.Performance characteristics for influenza A and B were established during February through March 2011 when influenza viruses A/California/7/2009 (2009 H1N1), A/Perth/16/2009 (H3N2), and B/Brisbane/60/2008 (Victoria-Like) were the predominant influenza viruses in circulation according to the Morbidity and Mortality Weekly Rapid Molecular Assay [influenza viral RNA or nucleic acid detection] A and B. NP 5 swab, nasal swab. 15-30 minutes 6. Yes/No 6. Immunofluorescence, Direct (DFA) or Indirect (IFA) Florescent Antibody Staining [antigen detection] A and B. NP 4 swab or wash, bronchial wash, nasal or endotracheal aspirate. 1-4 hours.Table 2: Available FDA-Cleared Rapid Influenza Diagnostic Tests (Antigen Detection Only) 1. These tests provide results in 10-15 minutes and differentiate between influenza A and B. Available FDA cleared tests as of August 2020.The last time the state saw a significant wave of influenza B was in 2019, when 12,950 cases of influenza B were recorded. In 2020, 720 notifications of influenza B were made. There were 57 in ...Information for the 2023-2024 Flu Season Thursday, August 17, 2023. CDC Reports Two Human Infections with Flu Viruses From Pigs Friday, August 4, 2023. H5N1 Bird Flu Found in Polish Domestic Cats Friday, July 21, 2023. Influenza Risk Assessment Tool (IRAT) Thursday, July 6, 2023. Virus Descriptions and Report Summaries Tuesday, July 4, 2023.Influenza (the flu) is a viral infection that causes symptoms like fever and chills, sneezing, coughing and a sore throat. The flu can be serious for some people, but if you are otherwise fit and healthy you usually don’t need to see a doctor. There is a vaccine available for the flu, and it’s recommended that everyone over the age of 6 ... types of influenza viruses: A, B, and C. Type A viruses are the most prevalent and are associated with most serious epidemics. Type B viruses produce a disease that is generally milder than that caused by type A. Type C viruses have never been associated with a large epidemic of human disease. Both type A and B viruses canMay 28, 2009 · Influenza A viruses infect a range of mammalian (e.g. pigs and horses) and avian species, whereas type B and C infections are largely restricted to humans. Only types A and B cause human disease of any concern. All of the currently identified 16 HA and 9 NA subtypes of influenza A viruses are maintained in wild, aquatic bird populations. Different types of COVID-19 and flu test kits use different testing methodologies. They can either be antigen-based or use molecular techniques. Diagnostic tests for viral antigens or RNA indicate a current infection. Antigen Tests. Antigen assays typically detect nucleocapsid proteins from a virus like SARS-CoV-2 or Flu A+B.Doctors & departments Overview Flu (influenza) is an infection of the nose, throat and lungs, which are part of the respiratory system. Influenza is commonly called the flu, but it's not the same as stomach "flu" viruses that cause diarrhea and vomiting. Most people with the flu get better on their own.May 28, 2009 · Influenza A viruses infect a range of mammalian (e.g. pigs and horses) and avian species, whereas type B and C infections are largely restricted to humans. Only types A and B cause human disease of any concern. All of the currently identified 16 HA and 9 NA subtypes of influenza A viruses are maintained in wild, aquatic bird populations. Flu Treatment. If you get sick with flu, influenza antiviral drugs may be a treatment option. Antiviral drugs work best when started early, such as one to two days after your flu symptoms begin. Check with your doctor promptly if you are at higher risk of serious flu complications and you get flu symptoms .A healthcare professional may be able to test for COVID-19, the flu and RSV at the same visit. Abbott offers several diagnostic tools to aid in fast, reliable respiratory virus testing. From our ID-NOW™ rapid system to the Alinity m Resp-4-Plex to the Panbio COVID-19/Flu A&B Rapid Panel test*, we are equipping clinicians with tools to ...Only type A and B cause human disease of any concern. Influenza virus is transmitted primarily by droplets or respiratory secretions of infected persons. Influenza occurs all over the world, with an annual global attack rate estimated at 5 – 10% in adults and 20 – 30% in children. Overview. Influenza virus testing is not required to make a clinical diagnosis of influenza in outpatients with suspected influenza, particularly during increased influenza activity when seasonal influenza A and B viruses are circulating in the local community. However, influenza virus testing can inform clinical management when the results may ... Influenza (Flu) Viruses There are two main types of human flu viruses: types A and B. The flu A and B viruses that routinely spread in people are responsible for seasonal flu epidemics each year. Flu A viruses can be broken down into sub-types depending on the genes that make up the surface proteins.Seasonal influenza (flu) vaccines are designed to protect against the four main groups of flu Type A and B viruses that research indicates are most likely to spread and cause illness among people during the upcoming flu season. All current U.S. flu vaccines protect against a flu A (H1) virus, a flu A (H3) virus, a flu B/Yamagata lineage virus ...Viral transport medium acceptable for collection of influenza specimens in 1 mL or 3 mL volumes can be used to transport swabs for COVID-19 testing. For swabs in saline: OP, NP or anterior nasal swabs may be placed in 1 to 3 mL of sterile saline (0.85 to 0.9%) in a sterile screw cap container.Strains of influenza B are exclusively contracted by humans, while A can be carried (and spread) by animals, however, both strains are transmitted mainly by respiratory droplets from coughing and contact with an infected person.Seasonal influenza (flu) vaccines are designed to protect against the four main groups of flu Type A and B viruses that research indicates are most likely to spread and cause illness among people during the upcoming flu season. All current U.S. flu vaccines protect against a flu A (H1) virus, a flu A (H3) virus, a flu B/Yamagata lineage virus ...For influenza A and influenza B viruses, selective amplification of target nucleic acid from the sample is achieved by the use of target-specific forward and reverse Influenza (flu): The flu is commonly caused by type A and B influenza strains. Symptoms are typically more severe than the common cold and can include coughing, fever (or chills), muscle aches, shortness of breath, and more.Jan 12, 2023 · There are 4 types of influenza viruses, types A, B, C and D. Influenza A and B viruses circulate and cause seasonal epidemics of disease. Influenza A viruses are further classified into subtypes according to the combinations of the hemagglutinin (HA) and the neuraminidase (NA), the proteins on the surface of the virus. Currently circulating in ... Influenza B almost exclusively infects humans and is less common than influenza A. Flu type B also mutates about two to three times more slowly than influenza A. Because humans are the natural host of influenza B, pandemics generally do not occur with influenza B viruses. 22. Although scientists can classify and monitor the different types of ...Influenza A is the most common type of influenza virus that causes the seasonal flu. Influenza A viruses are classified by subtypes based on surface proteins hemagglutinin (H) and neuraminidase (N). The viruses are named for the combination of proteins, such as A (H1N1) or A (H3N2). Influenza B.*The BD Veritor™ System for Rapid Detection of SARS-CoV-2 & Flu A+B is intended for the in vitro, simultaneous qualitative detection and differentiation of SARS-CoV-2 nucleocapsid antigen and/or influenza A and B nucleoprotein antigens directly from anterior nasal swab samples taken from individuals who are suspected of a viral respiratory infection consistent with COVID-19 by a healthcare ... Different types of COVID-19 and flu test kits use different testing methodologies. They can either be antigen-based or use molecular techniques. Diagnostic tests for viral antigens or RNA indicate a current infection. Antigen Tests. Antigen assays typically detect nucleocapsid proteins from a virus like SARS-CoV-2 or Flu A+B.During the 2020-2021 flu season, there was very low circulation of seasonal flu viruses. During September 27, 2020–May 22, 2021 in the United States, 1,899 (0.2%) of 1,081,671 clinical samples tested were positive for an influenza virus (713 [37.5%] influenza A and 1,186 [62.5%] influenza B). During that same period, public health ...Influenza B almost exclusively infects humans and is less common than influenza A. Flu type B also mutates about two to three times more slowly than influenza A. Because humans are the natural host of influenza B, pandemics generally do not occur with influenza B viruses. 22. Although scientists can classify and monitor the different types of ...The fastest molecular flu test just got faster and even better. Now with early detection and positive results in as few as 5 minutes, allowing you to make effective clinical decisions sooner. Abbott ID NOW is a rapid, instrument-based system for the qualitative detection of infectious diseases using isothermal nucleic acid amplification technology.The CDC Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay is a real-time reverse-transcription polymerase chain reaction (rRT-PCR) laboratory test that can simultaneously detect and differentiate between influenza A, influenza B, and SARS-CoV-2 in upper or lower respiratory specimens. The test is a highly accurate, nucleic acid-based diagnostic ...Influenza — commonly known as the flu — is a respiratory infection caused by flu viruses. There are three main types of influenza: A, B, and C. Types A and B are similar, but influenza B can ...Flu A and B cause the same types of symptoms, so it’s impossible to tell which variety you have from symptoms alone. Flu B symptoms can range from mild to severe. They often come on quickly and last for about a week.Rapid influenza diagnostic tests (RIDTs) detect influenza viral antigens in respiratory tract specimens. Available RIDTS detect and differentiate between type influenza A and B viruses, but do not specifically identify or differentiate subtypes of influenza A viruses. RIDTs are not recommended for use in hospitalized patients with suspected ...Background. Rapid influenza diagnostic tests (RIDTs) are immunoassays that can identify the presence of influenza A and B viral nucleoprotein antigens in respiratory specimens, and display the result in a qualitative way (positive vs. negative) (1). In the United States, a number of RIDTs are commercially available.Sep 28, 2022 · Similarities: Both COVID-19 and flu can have varying degrees of symptoms, ranging from no symptoms (asymptomatic) to severe symptoms. Common symptoms that COVID-19 and flu share include: Fever or feeling feverish/having chills. Cough. Shortness of breath or difficulty breathing. Follow recommended infection prevention and control measures1. SARS-CoV-2 Testing. Test for SARS-CoV-2 by nucleic acid detection 2. , 3 ; OR if not available, by SARS-CoV-2 antigen detection assay. 5. a) If SARS-CoV-2 Test result is positive, administer supportive care. If the patient is at high risk for progression to severe COVID-19 ... For influenza A and influenza B viruses, selective amplification of target nucleic acid from the sample is achieved by the use of target-specific forward and reverseDifferent types of COVID-19 and flu test kits use different testing methodologies. They can either be antigen-based or use molecular techniques. Diagnostic tests for viral antigens or RNA indicate a current infection. Antigen Tests. Antigen assays typically detect nucleocapsid proteins from a virus like SARS-CoV-2 or Flu A+B.Nov 14, 2022 · The CDC Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay is a real-time reverse-transcription polymerase chain reaction (rRT-PCR) laboratory test that can simultaneously detect and differentiate between influenza A, influenza B, and SARS-CoV-2 in upper or lower respiratory specimens. The test is a highly accurate, nucleic acid-based diagnostic ... Flu Treatment. If you get sick with flu, influenza antiviral drugs may be a treatment option. Antiviral drugs work best when started early, such as one to two days after your flu symptoms begin. Check with your doctor promptly if you are at higher risk of serious flu complications and you get flu symptoms .Jan 12, 2023 · There are 4 types of influenza viruses, types A, B, C and D. Influenza A and B viruses circulate and cause seasonal epidemics of disease. Influenza A viruses are further classified into subtypes according to the combinations of the hemagglutinin (HA) and the neuraminidase (NA), the proteins on the surface of the virus. Currently circulating in ... Results are for the identification and differentiation of RNA from SARS-CoV-2, Influenza A, Influenza B and RSV. Limitations This assay is intended for use only under the Food and Drug Administration's Emergency Use Authorization.Nov 7, 2022 · A healthcare professional may be able to test for COVID-19, the flu and RSV at the same visit. Abbott offers several diagnostic tools to aid in fast, reliable respiratory virus testing. From our ID-NOW™ rapid system to the Alinity m Resp-4-Plex to the Panbio COVID-19/Flu A&B Rapid Panel test*, we are equipping clinicians with tools to ... Type C causes infection but does not cause typical flu symptoms. Both influenza A and B have been linked to the development of Reye's syndrome, a potentially fatal complication that usually ...Rapid influenza diagnostic tests (RIDTs) detect influenza viral antigens in respiratory tract specimens. Available RIDTS detect and differentiate between type influenza A and B viruses, but do not specifically identify or differentiate subtypes of influenza A viruses. RIDTs are not recommended for use in hospitalized patients with suspected ...
Print. The Centers for Disease Control and Prevention (CDC) recognizes that school administrators, teachers, staff, and parents are concerned about influenza (flu), particularly its effects on children. Educators and staff can help slow the spread of respiratory illnesses, including flu. On this page, you will find information on preventing the .... 402
455. McKesson Brand #181-34125. Respiratory Test Kit McKesson Consult™ Strep A Test 25 Tests CLIA Waived. A rapid test for the qualitative detection of Strep A antigen in throa …. Easy-to-use flip step eliminates need for pipetting. Fast, accurate detection of Group A Strep with walk-away convenience. #1107841.cough. sore throat. runny or stuffy nose. muscle or body aches. headaches. fatigue (tiredness) some people may have vomiting and diarrhea, though this is more common in children than adults. *It’s important to note that not everyone with flu will have a fever. More information is available at Flu and COVID-19 symptoms.Print. The Centers for Disease Control and Prevention (CDC) recognizes that school administrators, teachers, staff, and parents are concerned about influenza (flu), particularly its effects on children. Educators and staff can help slow the spread of respiratory illnesses, including flu. On this page, you will find information on preventing the ...Influenza (flu): The flu is commonly caused by type A and B influenza strains. Symptoms are typically more severe than the common cold and can include coughing, fever (or chills), muscle aches, shortness of breath, and more.Full genome sequencing can reveal the approximately 13,500-letter sequence of all the genes of the influenza virus’ genome. The two influenza types (A and B) that cause seasonal epidemics have eight RNA gene segments. These genes contain instructions for making new viruses and play an important role in how influenza viruses cause infection.Influenza A viruses infect a range of mammalian (e.g. pigs and horses) and avian species, whereas type B and C infections are largely restricted to humans. Only types A and B cause human disease of any concern. All of the currently identified 16 HA and 9 NA subtypes of influenza A viruses are maintained in wild, aquatic bird populations.H1N1 flu is a subtype of influenza A. Subtypes of influenza A are categorized based on two proteins on the surface of the virus, hemagglutinin (H) and neuraminidase (N). There are many H and N subtypes, and each one is numbered. All H and N flu subtypes are influenza A viruses. Each influenza subtype has many different strains of influenza virus.Aug 22, 2023 · FluNet Summary. This content is last updated on 22 August 2023. National Influenza Centres (NICs) and other national influenza laboratories from 108 countries, areas or territories reported data to FluNet for the time period from 24 July 2023 to 06 August 2023* (data as of 18/08/2023 06:58:57AM UTC). The WHO GISRS laboratories tested more than ... Room temperature (15°C to 30°C/59°F to 86°F) Internal controls. Positive and negative included. External controls. Positive and negative included. PPA* (versus an FDA-cleared influenza A and B molecular assay) A: 81.5%, B: 80.9%. NPA* (versus an FDA-cleared influenza A and B molecular assay) A: 97.8%, B: 99.1%. Type C causes infection but does not cause typical flu symptoms. Both influenza A and B have been linked to the development of Reye's syndrome, a potentially fatal complication that usually ...Viral transport medium acceptable for collection of influenza specimens in 1 mL or 3 mL volumes can be used to transport swabs for COVID-19 testing. For swabs in saline: OP, NP or anterior nasal swabs may be placed in 1 to 3 mL of sterile saline (0.85 to 0.9%) in a sterile screw cap container.Table 2: Available FDA-Cleared Rapid Influenza Diagnostic Tests (Antigen Detection Only) 1. These tests provide results in 10-15 minutes and differentiate between influenza A and B. Available FDA cleared tests as of August 2020. Mar 30, 2023 · There are four types of influenza viruses: A, B, C, and D. Influenza A and B viruses cause seasonal epidemics of disease in people (known as flu season) almost every winter in the United States. Influenza A viruses are the only influenza viruses known to cause flu pandemics (i.e., global epidemics of flu disease). The four types of influenza are A, B, C, and D. Types A and B are widespread during most winters in the United States. Type C is milder than types A or B and does not spread as easily. Type D ...Influenza A is the most common type of influenza virus that causes the seasonal flu. Influenza A viruses are classified by subtypes based on surface proteins hemagglutinin (H) and neuraminidase (N). The viruses are named for the combination of proteins, such as A (H1N1) or A (H3N2). Influenza B.1. INTRODUCTION. Influenza outbreaks are seen every year during the colder months of the year. Until now, four influenza pandemics have been reported, including the H1N1 (1918), the H2N2 (1957), the H3N2 (1967) and the H1N1 pandemic in 2009. 1 In addition, seasonal flu is reporting in different countries every year.Only type A and B cause human disease of any concern. Influenza virus is transmitted primarily by droplets or respiratory secretions of infected persons. Influenza occurs all over the world, with an annual global attack rate estimated at 5 – 10% in adults and 20 – 30% in children. types of influenza viruses: A, B, and C. Type A viruses are the most prevalent and are associated with most serious epidemics. Type B viruses produce a disease that is generally milder than that caused by type A. Type C viruses have never been associated with a large epidemic of human disease. Both type A and B viruses canBackground. Rapid influenza diagnostic tests (RIDTs) are immunoassays that can identify the presence of influenza A and B viral nucleoprotein antigens in respiratory specimens, and display the result in a qualitative way (positive vs. negative) (1). In the United States, a number of RIDTs are commercially available..