Presentation on theme: "Prepared by Dr Alissar Rady, WHO Lebanon"— Presentation transcript:
1 Prepared by Dr Alissar Rady, WHO Lebanon Influenza A H1 N1Prepared byDr Alissar Rady, WHO Lebanon
2 Influenza Virus Types A and B Type A(Seasonal, avian, swine influenza,….)Type B(Seasonal influenza)Can cause significant diseaseGenerally causes milder disease but may also cause severe diseaseInfects humans and otherspecies (e.g., birds; H5N1)Limited to humansCan cause epidemics and pandemics (worldwide epidemics)Generally causes milder epidemicsWhile there are three types of influenza viruses—A, B, and C—only two cause significant disease in humans (A and B). Type B influenza viruses are limited to humans, whereas Type A viruses can cause severe disease in humans and affect more species.Influenza Type AType A influenza is considered to cause the most serious disease among the influenza viruses, although not all strains cause clinical disease. Influenza A can cause severe epidemics (as well as severe worldwide epidemics; or pandemics) among all ages. Influenza type A infects multiple species including people, birds, pigs, horses, and other animals. Wild birds are the natural hosts for these viruses.Influenza Type BInfluenza B viruses are usually found only in humans. Influenza B viruses can cause some morbidity and mortality among humans, but in general are associated with less severe epidemics (chiefly among children) than influenza A viruses. Although influenza type B viruses can cause human epidemics, they have not caused pandemics.Because avian influenza and all pandemic viruses are of the Type A variety, we will focus this session on Type A influenza viruses.
3 Circulating Influenza Strains and Pandemics in The 20th Century 1918: “Spanish Flu”1957: “Asian Flu”1968: “Hong Kong Flu”20-40 million deaths1-4 million deaths1-4 million deathsH3N2H2N2H1N1
5 Seasonal Epidemics vs. Pandemics Seasonal InfluenzaA public health problem each yearUsually some immunity built up from previous exposures to the same subtypeInfants and elderly most at riskInfluenza PandemicsAppear in the human population rarely and unpredictablyHuman population lacks any immunityAll age groups, including healthy young adultsWhile seasonal influenza occurs every year, pandemic influenza rarely occurs. Here we compare some features of seasonal influenza with features of pandemic influenza.While the population usually has some immunity built up from previous exposures to seasonal influenza, the human population lacks any immunity to pandemic influenza strains.In seasonal influenza epidemics, infants and the elderly are most at risk of illness and complications. But during an influenza pandemic, even healthy, young people are at increased risk for serious complications.Seasonal influenza strains are the result of Antigenic Drift, while pandemic influenza strains are the result of Antigenic Shift.
6 Prerequisites for pandemic influenza A new influenza virus emerges to which the general population has little/no immunityThe new virus must be able to replicate in humans and cause disease2 of the 3 prerequisites for a human pandemic have been metA novel influenza virus has emerged and the general population has demonstrated little or no immunityAnd the new virus has been able to replicate in humansThe main questions that remains are:Will the virus will develop into a form that is efficiently transmitted from one human to another? (thus meeting the criteria for a pandemic)If so, where, when, how quickly, and how severely?The first two of three prerequisites have been met:A novel virusVirus must be able to replicate in humans and cause diseaseNew virus must be efficiently transmitted from one human to anotherVirus can improve its transmissibility via two mechanisms:adaptive mutationgenetic reassortment(can take place in humans without prior adaptation in another mammalian species, such as the pig)The new virus must be efficiently transmitted from one human to another
11 Big dropletsfall on peoplesurfaces bed clothesCourtesy of CDC
12 Signs and Symptoms Human Influenza Type of infection Upper and lower respiratoryFeverYesHeadacheCoughRespiratory symptomsVaries; sore throat to difficulty breathingGastrointestinal symptomsUncommon, except children, elderlyRecovery2-7 daysIt can be difficult to tell if a patient has influenza because the signs and symptoms for influenza are similar to those for other diseases that may cause respiratory illnesses. If you do suspect influenza, there are a few differences between human influenza and avian influenza that you can assess, especially in the early days of illness.Human influenza usually causes both upper respiratory (sore throat runny nose) and lower respiratory (cough, bronchitis) symptoms. Common signs and symptoms include fever, headache, cough, sore throat, muscle ache, and exhaustion. Other respiratory symptoms may appear, varying from sore throat to difficulty breathing. Children and the elderly may also have gastrointestinal symptoms like diarrhea, vomiting and nausea, but adults uncommonly have gastrointestinal symptoms, except loss of apetitie. People generally recover anywhere from 2 to 7 days after symptoms appear. However, cough and muscle ache may last more than 14 days. Although influenza generally causes an upper respiratory infection with tracheobronchitis, it can progress to pneumonia and respiratory failure in some cases.Although similar initially, avian influenza differs from human influenza in its course. Avian influenza leads to a lower respiratory illness with variable upper respiratory involvement. Initial symptoms are similar to human influenza. These include fever, headache, cough, sore throat, muscle ache, and exhaustion. Gastrointestinal symptoms of watery diarrhea, vomiting, and abdominal pain have been more commonly reported from H5N1 patients (20-70% diarrhea rate depending on case series). Symptoms of a lower respiratory infection appear early in course of the illness. About five days after symptoms appear, patients often begin to have difficulty breathing leading to respiratory distress, and an increased respiratory rate may also be observed. By this time, cough is prominent, sputum production may occur sometimes containing blood. Most patients develop pneumonia with bilateral pulmonary infiltrates.Ref: Writing Committee on WHO Consultation. NEJM 353: , 2005
13 "The entire purpose is to Swine flu"The entire purpose is tolimit exposure“The Centers for Disease Control and Prevention hopes to have a vaccine to manufacturers within 6 months (??)
14 Non-pharmaceutical Interventions 1. Delay disease transmission and outbreak peak2. Decompress peak burden on healthcare infrastructure3. Diminish overall cases and health impactsDailyCases#1#2#3Days since First CasePandemic outbreak:No interventionWith intervention
15 Cough etiquette Respiratory etiquette Hand washing! Cover nose / mouth when coughing or sneezingHand washing!We have just discussed infection control measures in health care facilities to prevent patient to health care worker and patient to patient transmission of avian influenza. Next we will discuss how to prevent person to person spread of avian influenza in the community.Specific infection control policies and procedures may be easier to implement in a controlled environment such as a medical facility, but good infection control practices can also be adapted to prevent and control respiratory disease transmission in the community. The following measures to contain respiratory secretions are recommended for all individuals with symptoms of a respiratory infection such as avian influenza:-Cover the nose and mouth with a mask, tissue or cloth when coughing or sneezing, and dispose of the tissue in the nearest waste receptacle after use.-If a mask, tissues or cloth are not available, cough or sneeze into your upper sleeve versus your hands.-Perform hand hygiene (e.g., hand washing with non-antimicrobial soap and water, alcohol-based hand rub, or antiseptic hand wash) after having contact with respiratory secretions or contaminated objects.(NOTE TO REVIEWERS: PLEASE ADD IN USE OF LOCAL MATERIALS HERE)
16 Voluntary IsolationSeparation and restricted movement of ill persons with contagious disease (often in a hospital setting and Primarily individual level)Isolate severe and mild casesLocation of isolation (home, hospital) depends on several factors (severity of illness, the number of affected persons, the domestic setting)Do not wait for lab confirmationPlan for large number of severe casesProvide medical and social care
17 Voluntary QuarantineSeparation and restricted movement of well persons presumed exposedIdentification of contactsOften at home, but may be designated residential facility or hospitalApplied at the individual or community levelRegular health monitoring is essential part of quarantineSelf-health monitoring and reporting
18 Hand Washing Method Wet hands with clean (not hot) water Apply soap Rub hands together for at least 20 secondsRinse with clean waterDry with disposable towel or air dryUse towel to turn off faucetWhile not formally a type of PPE, we will first discuss hand hygiene, because it is the cornerstone of infection control! Always remember to wash hands in between contact with each new patient. This slide describes effective hand hygiene techniques:When washing hands with soap and water, first wet hands with water, then apply the amount of soap recommended by the manufacturer. Rub hands together for at least 20 seconds, covering all surfaces of the hands and fingers. Rinse hands with water, dry them thoroughly with a disposable towel, and use the towel to turn off the faucet. Of course, this assumes that clean water is available. If there is any doubt about this, boiled or bottled water, or water treated with chlorine tablets should be used.*Source: Guideline for Hand Hygiene in Health-care Settings. MMWR 2002; vol. 51, no. RR-16.
19 Alcohol-based Hand Rubs Effective if hands not visibly soiledMore costly than soap & waterMethodApply appropriate (3ml) amount to palmsRub hands together, covering all surfaces until dryIf hands are not visibly soiled, alcohol-based hand cleaners are also effective. When decontaminating hands with an alcohol-based hand rub, apply product to palm of one hand and rub hands together, covering all surfaces of hands and fingers, until hands are dry. The volume to use depends on the manufacturer directions, but usually a coin-sized amount in your hand is sufficient.
21 Patients Cared for at Home Potential for transmissionMust educate family caregiversFever / symptom monitoringInfection control measuresHand washingUse of available material as mask …As with any infectious disease, there is the potential for avian influenza to be transmitted in the home. Therefore, people within the home of an infected individual should be educated on the risk for transmission, and ideally wear personal protective equipment including gloves, gowns and surgical masks. If PPE items are unavailable, readily available materials such as tissues or cloths should be used. And hand hygiene, as always, is critically important in preventing the spread of avian influenza in the home. Finally, as will be discussed in a moment, anyone handling corpses should wear protective gear.
29 Antivirals- Oseltamivir Treatment is 75 mg twice a day for 5 days.Prophylaxis is 75 mg once a day for 7 days after last exposure.Prophylaxis:High risk exposure (household contacts)Moderate risk (unprotected very close exposure to sick animals; HCW with unprotected exposure to patients)Low risk exposure: no need for prophylaxis unless activation of exceptional measures.