* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Slide 1
Survey
Document related concepts
Eradication of infectious diseases wikipedia , lookup
Public health genomics wikipedia , lookup
Transmission (medicine) wikipedia , lookup
Viral phylodynamics wikipedia , lookup
Infection control wikipedia , lookup
Canine distemper wikipedia , lookup
Marburg virus disease wikipedia , lookup
Canine parvovirus wikipedia , lookup
Henipavirus wikipedia , lookup
Human mortality from H5N1 wikipedia , lookup
Transcript
Management of Suspect Cases of Human Infection with Avian Influenza A (H5N1) Virus 1 Outline • Part 1: Background and epidemiology of avian influenza A (H5N1) virus infection in humans Human H5N1 clusters Clinical features of human infection with H5N1 virus • Part 2: Assessing case patients: Collecting clinical and epidemiologic information Specimen collection and diagnostics Treatment Management of Suspect Cases of Human Infection with Avian Influenza A (H5N1) Virus Part 1: Epidemiology and Clinical Features 3 Part 1: Learning Objectives • Understand the epidemiology of known human H5N1 cases and risk factors • Importance of clusters • Recognize clinical features of H5N1 in humans 4 Epidemiology of Influenza A(H5N1) Virus Infection of Humans Photo: T. Uyeki, CDC 5 Global Epidemiology • 409 cases have been reported to WHO from 15 countries* • Case fatality proportion = 256/409: ~ 63% • Human surveillance has focused upon severe respiratory disease (pneumonia) 6 *Reported as of March 2, 2009 Progression of Human Cases Human Avian Influenza A (H5N1) Cases by Onset Date and Country (as of 23 November 2009) As of 23 March 2009, total of 412 cases were reported officially to WHO * Cases missing onset date are excluded: World Health Organization, Western Pacific Regional Office Communicable Disease Surveillance and Response 1 Viet Nam, 13 Indonesia, 3 Azerbaijan, 20 Egypt, 1 Turkey, 1 Iraq, 1 Nigeria ** CFR Trend: computed based on cumulative dead & total number of cases WHO Summary of H5N1 cases • Epidemiologic summary of H5N1* Median age: 18 years (range 3 months - 75 years) 90% of cases were aged <40 years Male to female ratio = 1:1 Median time to hospitalization: 4 days Case fatality proportion: ~60% Highest case fatality: 10-19 years (76%) Lowest case fatality: ≥50 years (40%) Median time to death: 9 days (range 2 – 31 days) *Update: WHO-confirmed human cases of avian influenza A(H5N1) infection, November 2003–May 2008. Weekly Epidemiological Record, NO. 46, 14 November, 2008 WHO Avian Influenza http://www.who.int/csr/disease/avian_influenza/en/ 9 Review Question 1 Which two countries have reported the most cases Influenza A (H5N1) to WHO to date? a. Indonesia and Vietnam b. Egypt and Thailand c. China and Cambodia d. India and China Answer: a. Indonesia and Vietnam Review Question 2 What age group has the highest reported case fatality rate from H5N1 virus infection? a. 0-9 years old b. 10-19 years old c. 20-29 years old d. > 50 years old Answer: 10 – 19 years old Risk Factors: Exposures in the Week Before Illness • Touching sick or dead poultry Slaughtering, preparing for cooking • Touching dead wild birds Photo: AP/ Bikas Das • Having sick or dead poultry in the household • Visiting a live poultry market 12 Risk Factors: Culture-Specific Risk • Eating uncooked duck blood • Defeathering of swans • Playing with dead chickens Photo: TIME Magazine / John Stanmeyer • Contact with roosters used in cock fighting 13 Avian to Human Transmission of H5N1 • Primary mode of transmission is avian-to-human (zoonotic): Exposure to infected poultry Preparing or consuming uncooked or undercooked H5N1 virus-infected poultry or poultry products • Indirect transmission may occur through: Inhalation of aerosolized H5N1 virus infected material Contact with surfaces contaminated with infected poultry feces Contact with infected animals that ate dead poultry 14 Human-to-Human Transmission of H5N1 Virus Infection • Probable but limited, non-sustained* humanto-human transmission Very rare, but documented Occurred during close, prolonged, unprotected contact with a human H5N1 case Mostly in family members Transmission in hospital setting reported *Currently, no evidence of sustained human-to-human H5N1 virus transmission 15 Human Influenza A(H5N1) Case Clusters Occurrence of H5N1 Clusters • >25% of all cases have occurred in clusters • Clusters are 2 or more H5N1 cases that are epidemiologically-linked Occurred in several countries Hong Kong (2003) Thailand (2004) Indonesia (2006) Human Case Cluster, Hong Kong 2003 • Family of five Hong Kong residents visited Fujian Province, southern China in late January 2003 • 7-year old girl developed pneumonia and died, was buried, but not tested • Four survivors returned to Hong Kong • Father and son were hospitalized with pneumonia; both confirmed with H5N1, father died • No direct link between cases and avian flu infection in poultry was found Human Case Cluster, Thailand 2004 • 11-year old girl who lived in a rural village with her aunt where poultry deaths occurred Mother lived near Bangkok (no poultry exposure) • The girl developed fever and lower respiratory tract disease, hospitalized with pneumonia Mother and aunt traveled to hospital to provide care • • • The girl died 24 hours later Mother and aunt became sick, were confirmed with H5N1 virus infection; mother died Probable human-to-human transmission of H5N1 virus from girl to her mother and aunt Human Case Cluster, Indonesia 2006 • A large H5N1 family cluster occurred in North Sumatra 1 probable + 7 confirmed H5N1 cases 7 deaths H5N1 virus was isolated from 7 cases Index case was likely infected by contact with sick/dead chickens Limited human-to-human-to-human transmission Interpretation of Case Clusters • Cases with similar illness onset dates Same exposure source, similar incubation period? • Cases with illness onset separated in time Similar exposure source, different incubation periods? Different exposure sources? Limited human-to-human transmission? 21 Significance of Case Clusters • Increase in number and size of clusters, or increase in number of mild cases can indicate: That H5N1 viruses are spreading to more people Possible increased adaptability of H5N1 viruses to humans • Signal for: An increased pandemic threat and a change in WHO Pandemic Alert Period Phases The beginning of a pandemic Early containment measures 22 Assessing for Possible Human-to- Human H5N1 Virus Transmission • • • Documented exposure to a confirmed, probable, or suspected human H5N1 case, AND The time interval between contact with a suspected, probable, or confirmed H5N1 case and illness onset is 7 days or less, AND No other sources of H5N1 exposures Such as: birds, other animals, feathers, droppings, fertilizers made of fresh bird droppings, live poultry markets, contaminated environments, or laboratory specimens H5N1 Cluster Summary • ~25% of confirmed H5N1 cases have occurred in clusters worldwide Mostly among blood related family members Most cluster cases had contact with sick birds • • • Evidence of limited, non-sustained, human-to-human contact has occurred Clinically mild pediatric H5N1 cases identified during investigations of severely ill index cases Changes in size, number or epidemiology of clusters could signal important viral changes/adaptability, or pandemic • Epidemiologic evidence that H5N1 virus can be transmitted from patients to healthcare workers Review Question 3 If you recognize a cluster of human H5N1 cases, what would cause you to suspect that human-to-human transmission of H5N1 virus has occurred? a. b. c. d. e. Documented exposure to a confirmed, probable, or suspected human H5N1 case The time interval between contact with a suspected, probable, or confirmed H5N1 case and illness onset is 7 days or less No other apparent source of H5N1 exposure 3 or more cases are reported H5N1 is isolated from common environment of cases Answer: a,b, and c Clinical Features of Human Infection with H5N1 Virus 26 H5N1 Viral Infection in Humans • Incubation period Generally from 2 to 7 days • Viral shedding period for H5N1 virus Still largely unknown May be 2 weeks or longer Longer for children and immune compromised 27 H5N1 Clinical Manifestations • Common signs and symptoms: Fever ≥38C, cough, shortness of breath, difficulty breathing • Other findings (less common): Sore throat, headache, muscle aches, diarrhea • Clinical findings are non-specific, and are similar to other common acute respiratory diseases Critical to ask about H5N1 exposures 28 Possible Complications of H5N1 Infection • Most common: pneumonia May progresses to respiratory failure May requires mechanical ventilation Acute respiratory distress syndrome (ARDS) • • Gastrointestinal disease Multi-organ failure Heart and kidney dysfunction • Neurologic symptoms Encephalitis, seizures, altered mental status, progression to coma 29 H5N1 Pathogenesis • • High H5N1 viral levels are associated with an abnormal inflammatory response Other blood changes Decreased white blood cell count Low lymphocyte count Mild to moderately decreased platelet count • Infection and inflammation contribute to respiratory failure and multi-organ failure Cytokine dysregulation (cytokine “storm”) 30 Review Question 4 a. b. c. d. e. f. g. What clinical signs and symptoms are pathognomonic (distinguishing) for Influenza A (H5N1) infection? Fever Cough Shortness of breath Sore throat Pneumonia Gastrointestinal symptoms None of the above Answer: g. These symptoms may typically occur, but they are non-specific and similar to other acute respiratory diseases. Part 1 Summary: Epidemiology • Most human H5N1 cases have been healthy children and young adults • Epidemiology and exposure sources critical to suspecting a case • Most H5N1 cases had direct contact with sick or dead poultry or birds in the week prior to illness onset • Limited, non-sustained human-to-human transmission of H5N1 virus is rare, but has occurred 32 Part 1 Summary: Clinical Manifestation • Signs and symptoms of H5N1 infection are non-specific and are observed in other respiratory diseases: Fever, cough, shortness of breath, difficulty breathing • Pneumonia • Peripheral blood changes may occur but are non-specific 33 Management of Suspect Cases of Human Infection with Avian Influenza A (H5N1) Virus Part 2: Diagnosis, Management, and Treatment Part 2: Overview • Clinically assessing suspected patients: • • Collecting clinical and epidemiologic information Diagnostic and laboratory tests Current recommendations for clinical treatment Part 2: Learning Objectives • Identify important sources of clinical and epidemiologic information • Recognize laboratory tests used for identification of new cases Clinical specimen collection, diagnostic and laboratory tests • Know the treatments and interventions for suspected case-patients and their contacts 36 Part 2: Learning Objectives, cont • Know what pharmaceutical treatments are available for seasonal and pandemic influenza • Understand the difference in the recommendations between seasonal vs. pandemic flu treatment 37 Assessing Suspected H5N1 Patients 38 Assessing Suspected H5N1 Patients Does the patient have findings consistent with H5N1 virus infection? 1. Collect clinical history and data on clinical findings 2. Evaluate epidemiological data 3. Consider clinical, laboratory, and epidemiologic information together 39 Clinical Data to Collect • Date of illness onset • Complications Type and date of onset • Signs and symptoms • Clinical specimens collected for H5N1 testing • Routine laboratory results • Precautions used, breaks in precautions 40 Clinical Data • Common signs and symptoms: Fever Cough Shortness of breath Difficulty breathing • Other signs and symptoms that may occur: Sore throat Sputum production (may be bloody) Diarrhea / abdominal pain Muscle aches Headache Runny nose 41 Clinical Complications • Respiratory failure Complication from pneumonia within a few days to 2 weeks after illness onset • • Acute Respiratory Distress Syndrome Multiple organ failure Renal dysfunction Cardiac dysfunction • Abnormal lab values Low lymphocytes: <1500 / mm3 Low platelets: < 150,000 / mm3 Normal lymphocyte count 1500 - 4000 / mm3 Normal platelet count 150,000 - 400,000 / mm3 42 Medical Charts Include: • Demographic information • Medical history • Illness signs and symptoms • Physical examination findings • Treatment • Laboratory testing results 43 Epidemiologic Context Potential exposure to H5N1 • Occupational exposure Animal culler, veterinarian, health care workers • Residence or travel in area affected by H5N1 outbreaks in birds or animals (e.g., poultry market) • Direct contact with dead or diseased birds or other animals in affected area • Close contact with a person with H5N1 virus infection, unexplained moderate or severe acute respiratory illness Warning! Even if NO reports of ill poultry in a location, there could be disease in that area, especially if poultry influenza vaccines are used or reporting is poor 44 Sample Patient Chart: Exposure History Contact with ill people? (If yes, date and name, relationship to patient) ___________________________________________ ___________________________________________ Contact with diseased poultry (Live or dead)? (If yes, date and location) ___________________________________________ ___________________________________________ Recent travel? (If yes, date and location) ___________________________________________ ___________________________________________ Other close patient contacts (Household members, close coworkers) ___________________________________________ Are any of these contacts ill? 45 Review Question 5 What are the critical pieces of epidemiologic information that must be collected from a patient with illness that is clinically compatible with Influenza A (H5N1) infection? Answer: Occupational exposure - Animal culler, veterinarian, health care workers Residence or travel in area affected by H5N1 outbreaks in birds or animals (e.g., poultry market) Direct contact with dead or diseased birds or other animals in affected area Close contact with a person with H5N1 virus infection, unexplained moderate or severe acute respiratory illness Use All Information • Clinical signs compatible with H5N1 virus infection • History suggests exposure to H5N1 virus 7 days prior to symptom onset • Are there multiple cases or respiratory deaths in the same family or in contacts? • Send samples for laboratory confirmation 47 Specimen Collection and Diagnostics Diagnostic and Laboratory Testing Suspected Human H5N1 Case • Clinical specimen collection • Diagnostic tests Laboratory testing • Imaging Chest X-ray 49 Clinical Specimens: Lower Respiratory Tract • H5N1 viruses primarily infect lower respiratory tract tissue Deep lung tissues • Best specimens for detecting H5N1 viruses: Lower respiratory tract Endotracheal aspirates from intubated, mechanically ventilated patients Bronchioalveolar lavage (BAL) 50 Other Clinical Specimens for H5N1 Testing • Upper respiratory tract has worse virus yield than lower respiratory tract Throat swabs better for detecting H5N1 virus than other upper respiratory tract locations Use for ambulatory patients • H5N1 virus has also been detected* in: Rectal swab and stool Blood serum and plasma *Cerebrospinal (CSF) specimens These clinicalfluid specimens should not be the primary sources used for H5N1 diagnosis 51 Collecting Specimens for H5N1 Testing • All respiratory secretions and bodily fluids of H5N1 patients should be considered potentially infected with H5N1 virus! • Collect specimens from different respiratory sites from the same patient on multiple days • Collect oropharyngeal and nasal/nasopharyngeal swabs from both ventilated and non- ventilated patients 52 Collecting Specimens, cont. • Respiratory Collect endotracheal specimens from mechanically ventilated patients Collect throat and nasal swabs from all patients Collect specimens as soon as possible • Blood May be useful for detection of H5N1 antibodies three weeks after infection Not useful for rapid detection of H5N1 virus infection for rapid detection of outbreaks Need to collect paired sample: acute and convalescent • Rectal swab or diarrheal stool • Not primary specimen for confirming H5N1 virus infection 53 Review Question 6 What are the optimal specimens to collect from a non-ambulatory suspected case of Influenza A(H5N1) infection? Answer: Lower respiratory tract; endotracheal aspirates from intubated, mechanically ventilated patients Review Question 7 What are the optimal specimens to collect from an ambulatory suspected case of Influenza A(H5N1) infection? Answer: Throat swabs Diagnosis Tests on respiratory samples (most common): • • • • PCR-based techniques Virus isolation Immunofluorescence Rapid antigen detection (Flu A or B) Tests on serum: • • Measurement of specific antibodies PCR-based techniques Other tools: • Chest X-Ray Tests on Respiratory Samples • Reverse-transcription polymerase chain reaction (RT-PCR) Primary method of confirming H5N1 virus infection Highly sensitive and specific • Virus Isolation “Gold standard” Requires BSL-3 laboratory Allows for characterization of the virus 57 Other Tests • Serological methods Require acute and convalescent sera (serum obtained >21 days from onset) • Immunoflorescence Requires H5 monoclonal antibody Can be difficult to interpret 58 Rapid Influenza Test • Commercially available • Results in 15 - 30 minutes • Detect human influenza A and B viruses • Very low accuracy to detect H5N1 virus and seasonal influenza Not sensitive or specific for detecting H5N1 virus May result in false negatives and false positives • NOT RECOMMENDED for DETECTION of H5N1 virus 59 Other Diagnostic Tools Peripheral blood • Decrease in the white blood cell count (WBC) Decrease in lymphocyte count (one type of white blood cell) • Mild to moderate decrease in the blood platelet count 60 Imaging Radiologic Imaging (X-ray) • Non-specific evidence of pneumonia on admission • Often progresses to bilateral, multi-lobar pneumonia • Diffuse or patchy infiltrates • Fluid in the space surrounding the lungs • Cavities may form in the lung tissue Severe H5N1 Pneumonia - Vietnam 2004 DAY 5 DAY 7 DAY 10 •Fever •Progressive pulmonary disease •Death Hien TT et al., New England J Med 2004;350:1179-1188 62 Review Question 8 What is the most sensitive and specific laboratory test for confirmation of influenza A (H5N1) infection in humans? a. b. c. d. Real-time PCR Rapid influenza test Chest X-ray Serology Answer: a. Real-Time RT-PCR A Clinician Should Suspect H5N1 Virus Infection: • Severe acute respiratory illness AND • Exposure 7 days before symptom onsets to: Sick poultry or wild birds Suspect , probable, confirmed H5N1 case OR • Residence in an area with known H5N1 virus infections of poultry or other animals OR • Occupational risk factors, or reported cases of severe respiratory illness among close contacts and household members 64 Diagnostic Tests • • If Patient is suspected human H5N1 case or meets other trigger criteria (link to trigger criteria) Then Patient’s specimen should be sent to a WHO H5 Reference Laboratory* for further influenza testing and confirmation * Every country should have access to at least one laboratory capable of H5N1 virus detection by RT-PCR 65 Clinical Treatment for Seasonal and Pandemic Influenza 66 Treatment for Influenza Viruses • Neuraminidase Inhibitors Oseltamivir Zanamivir • Other Treatments • Chemoprophylaxis • Clinical Management Top image located at: http://www.biota.com.au/?page=1021001&subpage=1021019. Bottom image located at: http://www.free-rx-drugstore.com/gb/. Antivirals 68 Antivirals • Used for the treatment and prevention of seasonal influenza A and B virus infections • Effectiveness against H5N1 virus infection is unknown • WHO recommended first line therapy for treatment and prevention of H5N1 virus infection • Treatment should be given as soon as possible • May be given as chemoprophylaxis to prevent H5N1 disease in exposed persons 69 Neuraminidase Inhibitors • Two drugs available: Oseltamivir (Tamiflu ®); Zanamivir (Relenza ®) • Inhibit the Neuraminidase enzyme which provides the bond between infected cell and new virus particles • Prevents the release of new virus particles from the infected cell • Virus particles cannot go on to infect other cells 70 Oseltamivir for Seasonal Influenza • • • • • Capsule or suspension administered by mouth Approved in the U.S. for treatment of seasonal influenza in children aged ≥1 year Pediatric dosage depends on age and weight Administered twice a day for 5 days Side effects: nausea, vomiting Effectiveness Reduces influenza symptoms by 1 day when administered within 2 days of illness onset Reduces lower respiratory tract complications, pneumonia, and hospitalization 71 H1N1 Oseltamivir Resistance • Seasonal H1N1 resistance observed EU in 2008 Prevalence varies: 0-60+% • H1N1 resistance elsewhere 8% in the U.S. None reported elsewhere • Implications for avian influenza H5N1 Need to know more about why H1N1 resistance occurred Theoretically viruses could swap genes, but evidence does not support this possibility European Center for Disease Prevention and Control Oseltamivir: Considerations • Precautions People with kidney disease (reduce dose) Pregnant or nursing females Reports of delirium in pediatric patients (mostly from Japan) • Resistance Can develop with treatment, but frequency of resistance to oseltamivir is low 73 Oseltamivir for H5N1 Infection Effectiveness for H5N1 treatment is unknown However is first line therapy for H5N1 infections 74 Recommended Treatment for Human H5N1 Infection WHO recommends Oseltamivir treatment • Optimal dosage, duration for H5N1 unknown • WHO recommends similar dosage to seasonal influenza (capsule and oral suspension) 75 mg twice per day, 7-10 days Pediatric dosing based upon age and weight Consider longer treatment, and higher doses (150 mg) on case by case basis, especially in patient with progressive disease 75 OseltamivirTreatment for Human H5N1 Infection • Should be started as early as possible in suspected H5N1 patients • Warranted even with late presentation • Resistance has been reported during treatment of a small number of H5N1 patients Zanamivir can treat oseltamivir resistant viruses 76 Treatment of Children • Different oseltamivir dosage Based on child’s weight Not approved in children <1 year old • No aspirin for children <18 years of age Risk of Reye’s syndrome with aspirin Use paracetemol or ibuprofen • Children potentially infectious for longer periods than adults after illness onset 77 Zanamivir • • • • Orally inhaled powder – administered by mouth via special device Approved in the U.S. for treatment of seasonal influenza in patients aged 7 years and older and for chemoprophylaxis in persons older than 5 years of age Treatment dosage for seasonal influenza is one puff in the morning and one at night for 5 days Side effects Wheezing, and breathing problems 78 Zanamivir: Effectiveness • Effectiveness in seasonal influenza Can reduce influenza symptoms by 1 day if administered within 48 hours Reduces lower respiratory tract complications Oseltamivir-resistant influenza A(H1N1) viruses remain sensitive to zanamivir 79 Zanamirvir: Considerations • Not recommended for People with chronic respiratory disease Pregnant or nursing females • Resistance Very low for human influenza A (H1 and H3) viruses 80 Zanamirvir for H5N1 Infection Effectiveness for H5N1 treatment is unknown Used as second line therapy for H5N1 infections when virus is resistant to oseltamivir 81 Adamantanes Amantadine and Rimantadine • Chemically related, orally administered drugs • Reduce viral replication of Influenza A viruses • No activity against Influenza B viruses • High frequency of resistance among circulating human influenza A (H3) viruses Resistance develops rapidly influenza A viruses • Adverse effects include gastrointestinal and neurological symptoms • NOT recommend for H5N1 treatment 82 Review Question 9 According to WHO, what drug is the first-line for treatment of Influenza A (H5N1) infection? a. b. c. d. Oseltamivir, 75 mg twice per day, 7-10 days Zanamirvir, 75 mg twice per day, 7-10 days Amandatine, 75 mg twice per day, 7-10 days Rimantadine, 75 mg twice per day, 7-10 days Answer: a. • Consider longer treatment, and higher doses (150 mg) on case by case basis • Pediatric dosing is based on age and weight Other Treatments 84 Corticosteroids • No proven effectiveness on clinical H5N1 infection • Risk of side effects, including opportunistic infections • May be considered on case by case basis for persistent septic shock with adrenal insufficiency 85 Recommended Treatment with Antibiotics • Antibiotic prophylaxis should be avoided • When pneumonia is present: Antibiotic treatment is appropriate Treat according to published evidence-based guidelines 86 Treatment for the Acute Respiratory Distress Syndrome (ARDS) • Therapy for H5N1 virus infection associated ARDS should be based upon published guidelines for ARDS Lung protective mechanical ventilation with low tidal volume 87 WHO Recommnedations: Antiviral Chemoprophylaxis for Human Infections with H5N1 Virus • Pre-exposure prophylaxis may be considered for Those involved in culling or disposing of infected poultry • Post-exposure prophylaxis should be considered for Household and close contacts of suspected or confirmed H5N1 cases Healthcare worker with exposure without appropriate PPE to suspected or confirmed H5N1 patients • Treatment depends on level of risk WHO recommends oseltamivir WHO. Rapid advice guidelines for pharmacological management of H5N1. 2006 88 Antiviral Chemoprophylaxis: High Risk WHO recommends Oseltamivir for chemoprophylaxis of high-risk groups: 75 mg / day for 7-10 days after the last known exposure High-risk: Household or family members and close contacts, including pregnant women, of a strongly suspected or confirmed H5N1 patient WHO. Rapid advice guidelines for pharmacological management of H5N1. 2006 89 Chemoprophylaxis: Moderate Risk Antiviral chemoprophylaxis may be considered in persons defined by WHO as having moderate risk Moderate Risk: Persons handling sick animals, decontaminating environments, without the appropriate use of PPE or without using PPE 100% of the time Unprotected and very close direct exposure to sick or dead animals infected with H5N1 virus or birds implicated in human cases Healthcare workers in close contact with strongly suspected or confirmed H5N1 patients (performing intubation, tracheal suctioning, delivering nebulized drugs, handling body fluids) without the appropriate use of PPE 90 Chemoprophylaxis: Low Risk Antiviral chemoprophylaxis is generally not recommended for low risk persons Low Risk: Healthcare workers not in close contact with a strongly suspected or confirmed H5N1 patient and having no direct contact with infectious material Healthcare workers in contact with H5N1 cases wearing appropriate PPE Culling of non-infected or likely non-infected animals Handlers of sick animals or decontaminating environments 91 while using appropriate PPE Clinical Management • Infection control: Isolate patient Implement infection control precautions – – All bodily fluids, secretions, clinical specimens should be considered potentially infectious Proper personal protective equipment (PPE) for caregivers • Supportive care: Supplemental Oxygen Mechanical ventilation for respiratory failure in the intensive care unit • For the health care provider, PPE and not prophylaxis is the first line of defense! 92 Summary • Oseltamivir is first line therapy for treatment and prevention of H5N1 virus infection Chemoprophylaxis is recommended depending on level of risk (low, moderate, high) • Treatment with antibiotics should be avoided 93 Part 2 Summary: Epidemiology and Diagnosis • Collect clinical and epidemiologic data from multiple sources • Identify and collect appropriate specimens for diagnostic testing Lower respiratory tract Multiple respiratory samples should be collected for H5N1 testing • Diagnostic Tests: Real-time reverse-transcription polymerase chain reaction (RT-RTPCR) is the most sensitive and timely method for confirming H5N1. Rapid influenza tests are not sensitive for detecting H5N1 94 Part 2 Summary: Clinical Management and Treatment • Consider all evidence together (epidemiologic, clinical and diagnostic) • Treatments and interventions for suspected H5N1 patients include Antiviral treatment with oseltamivir Oxygen and mechanical ventilation Supportive care 95 Glossary • • • • • • • • • • Case fatality proportion: The proportion (percentage) of all the cases of disease who died within a specific time period. Also know as the case fatality rate Incubation period The period of time between the exposure to a virus or disease causing pathogen and when the actual infection or disease onset begins. Viral shedding process that occurs when a virus is present in bodily secretions and can thereby be transmitted to another persons. Encephalitis Inflammation in the brain usually caused by a virus (viral encephalitis). Pathogenesis The origination and development of a disease or the mechanism through which the disease causes illness 96 Glossary • • • • • • Cytokine dysregulation (“cytokine storm”) A complicated and uncontrolled immune response caused by severe infections. This exaggerated and damaging immune response can lead to organ damage, multi-organ failure, and death. Symptoms include: hypotension, tachycardia, dyspnea, fever, ischemia, or insufficient tissue perfusion (especially involving the major organs), uncontrollable hemorrhage, and multisystem organ failure (caused primarily by hypoxia, tissue acidosis, and severe metabolism dysregulation Lower respiratory tract: Portion of the respiratory system that refers to the Trachea, Primary bonchi and lungs Upper respiratory tract Portion of the respiratory system that refers to the nasal cavity, pharynx and larynx 97 Glossary • • • • Sensitive Used to describe a test that is “accurate” or “sensitive” to cases of true disease The proportion of specimens that are infected with the Influenza A(H5N1) virus that test positive based on diagnostic criteria. Specificity Proportion of true negatives among specimens that are not infected with Influenza A(H5N1) virus. • • False negatives A case that tests negative for disease although they are actually infected • • False positive A person who tests positive for disease but are not actually infected • • Biosafety Level 3 (BSL3) The level of biocontainment and safety practices for facilities that work on potentially dangerous agents (biological or environmental). Level three is applicable for agents which cause serious or potentially lethal disease (e.g., anthrax, 98 SARS, Typhus, etc). References and Resources • • • • • • • WHO. Update: WHO-confirmed human cases of avian influenza A(H5N1) infection, 25 November 2003 – 24 November 2006. Weekly Epidemiological Record 2007;82:41-48. Recommendations and laboratory procedures for detection of avian influenza A(H5N1) virus in specimens from suspected human cases, August 2007. http://www.who.int/csr/disease/avian_influenza/guidelines/RecAIlabtestsAug07.pdf WHO. WHO Rapid Advice Guidelines for pharmacological management of human infection with avian influenza A (H5N1) virus. 2006 http://www.who.int/medicines/publications/WHO_PSM_PAR_2006.6.pdf WHO. Avian influenza, including influenza A (H5N1), in humans: WHO interim infection control guideline for health care facilities. 24 April 2006. http://www.wpro.who.int/NR/rdonlyres/EA6D9DF3-688D43161DF5553E7B1DBCD/0/InfectionControlAIinhumansWHOInterimGuidelinesfor2b_0628. pdf Clinical management of human infection with avian influenza A (H5N1) virus. 15 August 2007. http://www.who.int/csr/disease/avian_influenza/guidelines/ClinicalManagement07.pdf Risk of Influenza A (H5N1) Infection among Health Care Workers Exposed to Patients with Influenza A (H5N1), Hong Kong Carolyn Buxton Bridges, Katz JM, Seto WH, Chan PKS, Tsang D, Ho W, Mak KH, Lim W, Tam JS, Clarke M, Williams SG, Mounts AW, Bresee JS, Conn LA, Rowe T, Hu‐Primmer J, Abernathy RA, Lu X, Cox NJ, and Fukuda K. The Journal of Infectious Diseases 2000 181:1, 344-348 99