Influenza a h1 ni latest

Just-in-Time LectureInfluenza A(H1N1) (Swine Flu): A Global Outbreak (Version 11, first JIT lecture issued April 26)Tuesday, May 26, 2009 (01:30 AM EST) Rashid A. Chotani, MD, MPH, DTM Adjunct Assistant Professor Uniformed Services University of the Health Sciences (USUHS) 240-367-5370 chotani@gmail.com

Viral family: Orthomyxoviridae

Size: 80-200nm or .08 – 0.12 μm (micron) in diameter ,[object Object]

N (neuraminidase)Virus Credit: L. Stammard, 1995

Structure of the influenza hemagglutinin monomer HA monomer. Sites A-E are immunodominant epitopes (From Fields Virology, 2nd ed, Fields & Knipe, eds, Raven Press, 1990, Fig.40-4)

Structure of the influenza hemagglutinin trimer HA trimer. (From Fields Virology, 2nd ed, Fields & Knipe, eds, Raven Press, 1990, Fig.39-6)

Influenza A reservoir Wild aquatic birds are the main reservoir of influenza A viruses. Virus transmission has been reported from weild waterfowl to poultry, sea mammals, pigs, horses, and humans. Viruses are also transmitted between pigs and humans, and from poultry to humans. Equine influenza viruses have recently been transmitted to dogs. (From Fields Vriology (2007) 5th edition, Knipe, DM & Howley, PM, eds, Wolters Kluwer/Lippincott Williams & Wilkins, Philadelphia, Fig 48.1)

Influenza replication Replication of influenza A virus. After binding (1) to sialic acid-containing receptors, influenza is endocytosed and fuses (2) with the vesicle membrane. Unlike for most other RNA viruses, transcription (3) and replication (5) of the genome occur in the nucleus. Viral proteins are synthesized (4), helical nucleocapsid segments form and associate (6) with the M1 protein-lined membranes containing M2 and the HA and NA glycoproteins. The virus buds (7) from the plasma membrane with 11 nucleocapsid segments. (-), Negative sense; (+), positive sense; ER, endoplasmic reticulum. (From Medical Microbiology, 5th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Figure 60-2.)

Influenza pathogenesis Pathogenesis of influenza A virus. The symptoms of influenza are caused by viral pathologic and immunopathologic effects, but the infection may promote secondary bacterial infection. CNS, Central nervous system. (From Medical Microbiology, 5th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Figure 60-3.)

Definitions General Epidemic – a located cluster of cases Pandemic – worldwide epidemic Antigenic drift Changes in proteins by genetic point mutation & selection Ongoing and basis for change in vaccine each year Antigenic shift Changes in proteins through genetic reassortment Produces different viruses not covered by annual vaccine

Survival of Influenza Virus Surfaces and Affect of Humidity & Temperature* Hard non-porous surfaces 24-48 hours Plastic, stainless steel Recoverable for > 24 hours Transferable to hands up to 24 hours Cloth, paper & tissue Recoverable for 8-12 hours Transferable to hands 15 minutes Viable on hands <5 minutes only at high viral titers Potential for indirect contact transmission *Humidity 35-40%, Temperature 28C (82F) Source: Bean B, et al. JID 1982;146:47-51

Influenza The Normal Burden of Disease Seasonal Influenza Globally: 250,000 to 500,000 deaths per year In the US (per year) ~35,000 deaths >200,000 Hospitalizations $37.5 billion in economic cost (influenza & pneumonia) >$10 billion in lost productivity Pandemic Influenza An ever present threat

Swine Influenza A(H1N1)Introduction Swine Influenza (swine flu) is a respiratory disease of pigs caused by type A influenza that regularly cause outbreaks of influenza among pigs Most commonly, human cases of swine flu happen in people who are around pigs Swine flu viruses do not normally infect humans, however, human infections with swine flu do occur, and cases of human-to-human spread of swine flu viruses have been documented

Swine Influenza A(H1N1) History in US A swine flu outbreak in Fort Dix, New Jersey, USA occurred in 1976 that caused more than 200 cases with serious illness in several people and one death More than 40 million people were vaccinated However, the program was stopped short after over 500 cases of Guillain-Barre syndrome, a severe paralyzing nerve disease, were reported 30 people died as a direct result of the vaccination In September 1988, a previously healthy 32-year-old pregnant woman in Wisconsin was hospitalized for pneumonia after being infected with swine flu and died 8 days later. From December 2005 through February 2009, a total of 12 human infections with swine influenza were reported from 10 states in the United States

Swine Influenza A(H1N1) Transmission to Humans Through contact with infected pigs or environments contaminated with swine flu viruses Through contact with a person with swine flu Human-to-human spread of swine flu has been documented also and is thought to occur in the same way as seasonal flu, through coughing or sneezing of infected people

Swine Influenza A(H1N1) Transmission Through Species Human Virus Avian Virus Avian/Human Reassorted Virus Swine Virus Reassortment in Pigs

Swine Influenza A(H1N1) March 2009Timeline In March and early April 2009, Mexico experienced outbreaks of respiratory illness and increased reports of patients with influenza-like illness (ILI) in several areas of the country April 12, the General Directorate of Epidemiology (DGE) reported an outbreak of ILI in a small community in the state of Veracruz to the Pan American Health Organization (PAHO) in accordance with International Health Regulations April 17, a case of atypical pneumonia in Oaxaca State prompted enhanced surveillance throughout Mexico April 23, several cases of severe respiratory illness laboratory confirmed as influenza A(H1N1) virus infection were communicated to the PAHO Sequence analysis revealed that the patients were infected with the same strain detected in 2 children residing in California Samples from the Mexico outbreak match swine influenza isolates from patients in the United States Source: CDC

Swine Influenza A(H1N1) March 2009Facts Virus described as a new subtype of A/H1N1 not previously detected in swine or humans CDC determines that this virus is contagious and is spreading from human to human The virus contains gene segments from 4 different influenza types: North American swine North American avian North American human and Eurasian swine

Swine Influenza A(H1N1) US Response The Strategic National Stockpile (SNS) is releasing one-quarter of its Anti-viral drugs Personal protective equipment and Reparatory protection devices President Obama today asked Congress for an additional $1.5 billion to fight the swine flu On April 27, 2009, the CDC issued a travel advisory that recommends against all non-essential travel to Mexico Source: CDC

Swine Influenza A(H1N1) Global Response The WHO raised the alert level to Phase 5 WHO’s alert system was revised after Avian influenza began to spread in 2004, and April 27 was the first time it was raised above Phase 3 and on April 29 to Phase 5. European Union (EU) issued a travel advisory to the 27 EU member countries recommending that “non-essential” travel to affected parts of the U.S. and Mexico be suspended Source: WHO

Swine Influenza A(H1N1) May 25, 2009Status Update MEXICO: March 01-May 22, a total of 4,174 Laboratory confirmed cases, with 80 deaths and 1311 hospitalizations (for pneumonia) reported in 32 of 32 States UNITED STATES: March 28-May 25, a total of 6,764 Laboratory confirmed cases, with 10 deaths (Arizona 3; Missouri 1; New York 1; Texas 3; Utah 1 and; Washington 1) from 48 States (including District of Columbia) Over 100 Hospitalizations Most cases mild CANADA: As of May 25, a total of 921 Laboratory confirmed cases, with one deaths (1 Alberta) from 10 of 13 States 116 new Laboratory confirmed cases May 25 Most cases mild Source: Secretaria de Salud, Mexico, CDC, Public Health Agency of Canada, European CDC, WHO

Swine Influenza A(H1N1) May 25, 2009Status Update EUROPEAN UNION & EFTA COUNTRIES: April 27- May 25, a total of 360 Laboratory confirmed cases, with no deaths from 19 countries 11 confirmed cases reported on May 24 130 in-country transmissions Vast majority of cases reported between 20-49 years of age Most cases (except 1) report mild disease GLOBALLY: March 1-May 25, a total of 12,727 Laboratory confirmed cases, from 46 countries 92 Deaths among laboratory confirmed cases from 4 countries Mexico: 80 deaths US: 10 deaths Canada: 01 death Costa Rica: 01 death Source: Secretaria de Salud, Mexico, CDC, Public Health Agency of Canada, European CDC, WHO

Swine Influenza A(H1N1)MMRW Report, April 28 MMWR, April 28, 2009 / 58(Dispatch);1-3 47 patients reported to CDC with known ages (out of 64) the median age was 16 years (range: 3-81 years) 38 (81%) were aged <18 years 51% of cases were in males Of the 25 cases with known dates of illness onset, onset ranged from March 28 to April 25 Five patients hospitalized Of 14 patients with known travel histories 3 had traveled to Mexico 40 of 47 patients (85%) had not been linked to travel or to another confirmed case Source: CDC. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm58d0428a2.htm

Swine Influenza A(H1N1)MMRW Report, April 30 MMWR, April 30, 2009 / 58(Dispatch);1-3 NYC school (high school A) 2,686 students and 228 staff members April 23-24, 222 students visited the school nursing office and left school because of illness DOHMH collect nasopharyngeal swabs from any symptomatic students April 24 (Friday), DOHMH collected nasopharyngeal swabs from five newly symptomatic students identified by the school nurse and four newly symptomatic students identified at a nearby physician's office April 27, School closed DOHMH also provided nasopharyngeal test kits to selected physicians' offices in the vicinity of high school A April 26, 7 of 9 specimens collected on April 24 were positive for the new strain of influenza April 26-28, 37 (88%) of 42 specimens collected tested positive, bringing the total number of confirmed cases to 44 April 27 DOHMH conducted telephone interviews with the 44 patients Median age was 15 years (range: 14-21 years) All were students, with the exception of one student teacher aged 21 years Thirty-one (70%) of the 44 were female Thirty (68%) were non-Hispanic white; seven (16%) were Hispanic; two (5%) were non-Hispanic black; and five (11%) were other races Four patients reported travel outside NYC within the United States in the week before symptom onset, and an additional patient traveled to Aruba in the 7 days before symptom onset. None of the 44 patients reported recent travel to California, Texas, or Mexico Source: CDC. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm58d0428a2.htm

Swine Influenza A(H1N1) MMRW Report, April 30 MMWR, April 30, 2009 / 58(Dispatch);1-3 Illness onset dates ranged from April 20 to April 24 10 (23%) of the patients had illness onset on April 22, and 28 (64%) had illness onset on April 23 (Figure). Among 35 patients who reported a maximum temperature, the mean was 102.2°F (39.0°C) (range: 99.0-104.0°F [37.2--40.0°C]) In total, 42 (95%) patients reported subjective fever plus cough and/or sore throat, meeting the CDC definition for influenza-like illness (ILI) At the time of interview on April 27, 37 patients (84%) reported that their symptoms were stable or improving, three (7%) reported worsening symptoms (two of whom later reported improvement), and four (9%) reported complete resolution of symptoms Only one reported having been hospitalized for syncope and released after overnight observation Source: CDC. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm58d0428a2.htm

Laboratory-Confirmed Cases of New Influenza A(H1N1) by Countries, May 25, 2009 12,727 Cases & 92 Deaths 10 80 1 1 Chinese Taipei has reported 1 confirmed case of influenza A (H1N1) with 0 deaths. Cases from Chinese Taipei are included in the cumulative totals provided in the table above.

Global Distribution of Reported Cumulative & Probable Cases of Swine Influenza A(H1N1) by Countries, May 25, 2009 (08:00 GMT) US 6,767 cases 10 deaths Total 12,727 Cases 92 deaths 12,727 Cases & 92 Deaths Source: WHO

Swine Influenza A(H1N1) USCase Definitions A confirmed case of swine influenza A (H1N1) virus infection is defined as a person with an acute febrile respiratory illness with laboratory confirmed swine influenza A (H1N1) virus infection at CDC by one or more of the following tests: real-time RT-PCR viral culture A probable case of swine influenza A (H1N1) virus infection is defined as a person with an acute febrile respiratory illness who is: positive for influenza A, but negative for H1 and H3 by influenza RT-PCR, or positive for influenza A by an influenza rapid test or an influenza immunofluorescence assay (IFA) plus meets criteria for a suspected case A suspected case of swine influenza A (H1N1) virus infection is defined as a person with acute febrile respiratory illness with onset within 7 days of close contact with a person who is a confirmed case of swine influenza A (H1N1) virus infection, or within 7 days of travel to community either within the United States or internationally where there are one or more confirmed swine influenza A(H1N1) cases, or resides in a community where there are one or more confirmed swine influenza cases. Source: CDC

Swine Influenza A(H1N1) USCase Definitions Infectious period for a confirmed case of swine influenza A(H1N1) virus infection is defined as 1 day prior to the case’s illness onset to 7 days after onset Close contact is defined as: within about 6 feet of an ill person who is a confirmed or suspected case of swine influenza A(H1N1) virus infection during the case’s infectious period Acute respiratory illness is defined as recent onset of at least two of the following: rhinorrhea or nasal congestion, sore throat, cough (with or without fever or feverishness) High-risk groups: A person who is at high-risk for complications of swine influenza A(H1N1) virus infection is defined as the same for seasonal influenza (see Reference) Source: CDC

Swine Influenza A(H1N1) Guidelines for Clinicians Clinicians should consider the possibility of swine influenza virus infections in patients presenting with febrile respiratory illness who live in areas where human cases of swine influenza A(H1N1) have been identified or have traveled to an area where human cases of swine influenza A(H1N1) has been identified or have been in contact with ill persons from these areas in the 7 days prior to their illness onset If swine flu is suspected, clinicians should obtain a respiratory swab for swine influenza testing and place it in a refrigerator (not a freezer) once collected, the clinician should contact their state or local health department to facilitate transport and timely diagnosis at a state public health laboratory Source: CDC

Swine Influenza A(H1N1) Guidelines for Clinicians Signs and Symptoms Influenza-like-illness (ILI) Fever, cough, sore throat, runny nose, headache, muscle aches. In some cases vomiting and diarrhea. (These cases had illness onset during late March to mid-April 2009) Cases of severe respiratory disease, requiring hospitalization including fatal outcomes, have been reported in Mexico The potential for exacerbation of underlying chronic medical conditions or invasive bacterial infection with swine influenza virus infection should be considered Non-hospitalized ill persons who are a confirmed or suspected case of swine influenza A (H1N1) virus infection are recommended to stay at home (voluntary isolation) for at least the first 7 days after illness onset except to seek medical care Source: CDC

Swine Influenza A(H1N1) Guidelines for Clinicians FDA Issues Authorizations for Emergency Use (EUAs) of Antivirals On April 27, 2009, the U.S. Food and Drug Administration (FDA) issued EUAs in response to requests by the Centers for Disease Control and Prevention (CDC) for the swine flu outbreak One of the reasons the EUAs could be issued was because the U.S. Department of Health and Human Services (HHS) declared a public health emergency on April 26, 2009 The swine influenza EUAs aid in the current response: Tamiflu:Allow for Tamiflu to be used to treat and prevent influenza in children under 1 year of age, and to provide alternate dosing recommendations for children older than 1 year. Tamiflu is currently approved by the FDA for the treatment and prevention of influenza in patients 1 year and older. Tamiflu and Relenza: Allow for both antivirals to be distributed to large segments of the population without complying with federal label requirements that would otherwise apply to dispensed drugs and to be accompanied by written information about the emergency use of the medicines. Source: FDA

Swine Influenza A(H1N1) Biosafety Guidelines for Laboratory Workers Diagnostic work on clinical samples from patients who are suspected cases of swine influenza A (H1N1) virus infection should be conducted in a BSL-2 laboratory All sample manipulations should be done inside a biosafety cabinet (BSC) Viral isolation on clinical specimens from patients who are suspected cases of swine influenza A (H1N1) virus infection should be performed in a BSL-2 laboratory with BSL-3 practices (enhanced BSL-2 conditions) Additional precautions include: recommended personal protective equipment (based on site specific risk assessment) respiratory protection - fit-tested N95 respirator or higher level of protection shoe covers closed-front gown double gloves eye protection (goggles or face shields) Waste all waste disposal procedures should be followed as outlined in your facility standard laboratory operating procedures Source: CDC

Swine Influenza A(H1N1) Biosafety Guidelines for Laboratory Workers Appropriate disinfectants 70 per cent ethanol 5 per cent Lysol 10 per cent bleach All personnel should self monitor for fever and any symptoms. Symptoms of swine influenza infection include diarrhea, headache, runny nose, and muscle aches Any illness should be reported to your supervisor immediately For personnel who had unprotected exposure or a known breach in personal protective equipment to clinical material or live virus from a confirmed case of swine influenza A (H1N1), antiviral chemoprophylaxis with zanamivir or oseltamivir for 7 days after exposure can be considered Source: CDC

Swine Influenza A(H1N1) Biosafety Guidelines for Laboratory Workers FDA Issues Authorizations for Emergency Use (EUAs) of Diagnostic Tests On April 27, 2009, the U.S. Food and Drug Administration (FDA) issued EUAs in response to requests by the Centers for Disease Control and Prevention (CDC) for the swine flu outbreak One of the reasons the EUAs could be issued was because the U.S. Department of Health and Human Services (HHS) declared a public health emergency on April 26, 2009 The swine influenza EUAs aid in the current response: Diagnostic Test: Allow CDC to distribute the rRT-PCR Swine Flu Panel diagnostic test to public health and other qualified laboratories that have the equipment and personnel to perform and interpret the results. Source: CDC

Swine Influenza A(H1N1) Guidelines for General Population Covering nose and mouth with a tissue when coughing or sneezing Dispose the tissue in the trash after use. Handwashing with soap and water Especially after coughing or sneezing. Cleaning hands with alcohol-based hand cleaners Avoiding close contact with sick people Avoiding touching eyes, nose or mouth with unwashed hands If sick with influenza, staying home from work or school and limit contact with others to keep from infecting them

Swine Influenza A(H1N1) Treatment No vaccine available Antivirals for the treatment and/or prevention of infection: Oseltamivir (Tamiflu) or Zanamivir (Relenza) Use of anti-virals can make illness milder and recovery faster They may also prevent serious flu complications For treatment, antiviral drugs work best if started soon after getting sick (within 2 days of symptoms) Warning! Do NOT give aspirin (acetylsalicylic acid) or aspirin-containing products (e.g. bismuth subsalicylate – Pepto Bismol) to children or teenagers (up to 18 years old) who are confirmed or suspected ill case of swine influenza A (H1N1) virus infection; this can cause a rare but serious illness called Reye’s syndrome. For relief of fever, other anti-pyretic medicationsare recommended such as acetaminophen or non steroidal anti-inflammatory drugs. Source: CDC

Swine Influenza A(H1N1) Treatment Dosing recommendations for antiviral treatment of children younger than 1 year using oseltamivir. Recommended treatment dose for 5 days. <3 months: 12 mg twice daily; 3-5 months: 20 mg twice daily; 6-11 months: 25 mg twice daily Dosing recommendations for antiviral chemoprophylaxis of children younger than 1 year using oseltamivir. Recommended prophylaxis dose for 10 days. <3 months: Not recommended unless situation judged critical due to limited data on use in this age group; 3-5 months: 20 mg once daily; 6-11 months: 25 mg once daily Source: CDC

Swine Influenza A(H1N1) Other Protective Measures Defining Quarantine vs. Isolation vs. Social-Distancing Isolation: Refers only to the sequestration of symptomatic patents either in the home or hospital so that they will not infect others Quarantine: Defined as the separation from circulation in the community of asymptomatic persons that may have been exposed to infection Social-Distancing: Has been used to refer to a range of non-quarantine measures that might serve to reduce contact between persons, such as, closing of schools or prohibiting large gatherings Source: CDC

Swine Influenza A(H1N1) Other Protective Measures Personnel Engaged in Aerosol Generating Activities CDC Interim recommendations: Personnel engaged in aerosol generating activities (e.g., collection of clinical specimens, endotracheal intubation, nebulizer treatment, bronchoscopy, and resuscitation involving emergency intubation or cardiac pulmonary resuscitation) for suspected or confirmed swine influenza A (H1N1) cases should wear a fit-tested disposable N95 respirator Pending clarification of transmission patterns for this virus, personnel providing direct patient care for suspected or confirmed swine influenza A (H1N1) cases should wear a fit-tested disposable N95 respirator when entering the patient room Respirator use should be in the context of a complete respiratory protection program in accordance with Occupational Safety and Health Administration (OSHA) regulations. Source: CDC

Swine Influenza A(H1N1) Other Protective Measures Infection Control of Ill Persons in a Healthcare Setting Patients with suspected or confirmed case-status should be placed in a single-patient room with the door kept closed. If available, an airborne infection isolation room (AIIR) with negative pressure air handling with 6 to 12 air changes per hour can be used. Air can be exhausted directly outside or be recirculated after filtration by a high efficiency particulate air (HEPA) filter. For suctioning, bronchoscopy, or intubation, use a procedure room with negative pressure air handling. The ill person should wear a surgical mask when outside of the patient room, and should be encouraged to wash hands frequently and follow respiratory hygiene practices. Cups and other utensils used by the ill person should be washed with soap and water before use by other persons. Routine cleaning and disinfection strategies used during influenza seasons can be applied to the environmental management of swine influenza. Source: CDC

Swine Influenza A(H1N1) Other Protective Measures Infection Control of Ill Persons in a Healthcare Setting Standard, Droplet and Contact precautions should be used for all patient care activities, and maintained for 7 days after illness onset or until symptoms have resolved. Maintain adherence to hand hygiene by washing with soap and water or using hand sanitizer immediately after removing gloves and other equipment and after any contact with respiratory secretions. Personnel providing care to or collecting clinical specimens from suspected or confirmed cases should wear disposable non-sterile gloves, gowns, and eye protection (e.g., goggles) to prevent conjunctival exposure. Source: CDC

Types of Protective Masks Surgical masks Easily available and commonly used for routine surgical and examination procedures High-filtration respiratory mask Special microstructure filter disc to flush out particles bigger than 0.3 micron. These masks are further classified:• oil proof• oil resistant• not resistant to oil The more a mask is resistant to oil, the better it is The masks have numbers beside them that indicate their filtration efficiency. For example, a N95 mask has 95% efficiency in filtering out particles greater than 0.3 micron under normal rate of respiration. The next generation of masks use Nano-technologywhich are capable of blocking particles as small as 0.027 micron.

Summary WHO raised the alert level to Phase 5 on April 29, 2009 There is a disparity between the % case-fatality-rate between Mexico (1.91%), Canada (0.11%) and USA (0.15%) The overall global case-fatality (12,727 cases and 92 deaths) is 0.72% ~ 1,500 cases worldwide (reported) needed hospitalization Majority in Mexico Epidemiological Data US Median Age 16 years (range: 1-81 years) Over 80% of the cases in <18 years 60% female; 40% Male Mexico Majority of the cases reported in health young adults 77.5% of the deaths were reported in healthy young adults, 20-54 years Individuals 60+ seem to be protected as the number of cases and have a lower case-fatality compared to the rest of the population 56% female; 44% Male EU Majority of the cases reported in health young adults (20-29 years). In-country transmission (36%) has been documented No vaccine is available Anti-virals available

Timeline of Emergence Influenza A Viruses in Humans Reassorted Influenza virus (Swine Flu) H1 1976 Swine Flu Outbreak, Ft. Dix Avian Influenza H7 H9 H5 H5 H1 H3 H2 H1 2009 1918 1957 1968 1977 1997 2003 Asian Influenza H2N2 Hong Kong Influenza H3N2 Russian Influenza Spanish Influenza H1N1 1998/9

Influenza a h1 ni latest

Recomendados

Recomendados

Mais conteúdo relacionado

Mais procurados

Mais procurados (19)

Destaque

Destaque (8)

Semelhante a Influenza a h1 ni latest

Semelhante a Influenza a h1 ni latest (20)

Mais de Bea Galang

Mais de Bea Galang (20)

Último

Último (20)

Influenza a h1 ni latest