bealeavianflu

Avian Flu: The Next Pandemic of the 21st Century?: 

Avian Flu: The Next Pandemic of the 21st Century? Presented by: Leslie Beale, Ed.D.

Presentation framework: 

“Science knows no country, because knowledge belongs to humanity, and is the torch which illuminates the world.” (Louis Pasteur) “Knowing is not enough, we must apply; willing is not enough, we must act.” (Johann Wolfgang Von Goethe) Presentation framework

Slide3: 

2005--The Year of the Rooster

Presentation Outline: 

Presentation Outline Description, risks, symptoms, and treatment of avian influenza How bird flu spreads H5N1 bird flu virus description Risk to humans from H5N1 virus Treatment of the H5N1 virus Vaccine for the H5N1 virus Confirmed human cases of H5N1 virus Latest news on the H5N1 virus CDC recommendations related to H5N1 virus H5N1 virus as a biological weapon Directions for future research Discussion questions for students References

What is avian influenza (bird flu)?: 

What is avian influenza (bird flu)? Bird flu is an infection caused by avian (bird) influenza (flu) A viruses. This flu virus can affect domestic and wild bird species including chickens, turkeys, ducks, geese, gulls, shorebirds. Aquatic birds (ducks, shore birds, and gulls) are the natural reservoirs for the avian flu viruses. The waterfowl do not develop disease when infected with avian influenza (asymptomatic).

How are bird flu viruses different from human flu viruses? : 

How are bird flu viruses different from human flu viruses? There are many different subtypes of type flu A viruses. These subtypes differ because of certain proteins in the flu A virus. There are 16 different HA subtypes and 9 different NA subtypes of flu A viruses. Many different combinations of HA and NA proteins are possible. Each combination is a different subtype. All subtypes of flu A viruses are found in birds. They do not usually infect humans, even though we know they can do so. Human flu viruses are those subtypes that occur widely in humans. There are only three known subtypes of human flu viruses (H1N1, H1N2, and H3N2); it is likely that some genetic parts of current human flu A viruses came from birds originally. Flu A viruses are constantly changing, and they might adapt over time to infect and spread among humans.

What is the risk to humans from bird flu?: 

What is the risk to humans from bird flu? The risk from bird flu is generally low to most people because the viruses occur mainly among birds and do not usually infect humans. However, during an outbreak of bird flu among poultry (domesticated chicken, ducks, turkeys), there is a possible risk to people who have contact with infected birds or surfaces that have been contaminated with excretions from infected birds. The current outbreak of avian influenza A (H5N1) among poultry in Asia is an example of a bird flu outbreak that has caused human infections and deaths. In such situations, people should avoid contact with infected birds or contaminated surfaces, and should be careful when handling and cooking poultry.

What are the symptoms of bird flu in humans?: 

What are the symptoms of bird flu in humans? Symptoms of bird flu in humans have ranged from typical flu-like symptoms (fever, cough, sore throat and muscle aches) to eye infections, pneumonia, severe respiratory diseases (such as acute respiratory distress), and other severe and life-threatening complications. The symptoms of bird flu may depend on which virus caused the infection.

How is bird flu in humans treated?: 

How is bird flu in humans treated? Studies suggest that the prescription medicines approved for human flu viruses would work in preventing bird flu infection in humans. However, flu viruses can become resistant to these drugs, so these medications may not always work.

How does bird flu spread?: 

How does bird flu spread? Infected birds shed flu virus in their saliva, nasal secretions, and feces. Susceptible birds become infected when they have contact with contaminated excretions or surfaces that are contaminated with excretions. It is believed that most cases of bird flu infection in humans have resulted from contact with infected poultry or contaminated surfaces.

What is the H5N1 bird flu? : 

What is the H5N1 bird flu? Outbreaks of influenza H5N1 occurred among poultry in eight countries in Asia (Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand, and Vietnam) during late 2003 and early 2004. At that time, more than 100 million birds in the affected countries either died from the disease or were killed in order to try to control the outbreak. By March 2004, the outbreak was reported to be under control. Beginning in late June 2004, however, new deadly outbreaks of influenza H5N1 among poultry were reported by several countries in Asia (Cambodia, China, Indonesia, Malaysia [first-time reports], Thailand, and Vietnam). It is believed that these outbreaks are ongoing. Human infections of influenza A (H5N1) have been reported in Thailand, Vietnam and Cambodia.

Why the concern?: 

Why the concern? The H5N1 virus mutates rapidly (unique in how fast it mutates) and can infect other animal species like pigs. causes severe disease or fatality in humans. has a high pathogenicity (death for birds within 48 hours). This pathogenicity has become progressively more potent over time. birds that survive infection excrete the virus for at least 10 days making it easier to spread the virus at live poultry markets and by migratory birds. survives several days longer in the environment compared with when it first emerged n 1997. has expanded its mammalian host range including pigs. has been found increasingly in dead migratory birds (which usually is not affected by the virus).

Major outbreaks of H5N1Avian Influenza (as of 6/28/05): 

Major outbreaks of H5N1Avian Influenza (as of 6/28/05) Birds 1997 Hong Kong 1.5 million birds culled in 3 days 2003-05 Asia 120 million+ birds died/culled 4/05-5/05 China 6,000 migrating geese/100 a day died People 108 human cases, 54 fatal; unofficial numbers are higher. Countries Cambodia, China (Taipei China & People’s Republic of China), Hong Kong, Indonesia, Japan, Laos, Malaysia, South Korea, Thailand, Vietnam.

Transmission of H5N1: 

Transmission of H5N1 Routes of bird-to-bird transmission include: Airborne transmission if birds are in close proximity Direct contact with contaminated respiratory secretions or fecal material Broken contaminated eggs infecting healthy chicks Movement of infected birds between flocks Movement of contaminated clothing, shoes, equipment, egg flats, feed trucks Contact with infected wild birds & waterfowl Fecal contamination of water Garbage flies

Global path of H5N1 : 

Global path of H5N1

What is the risk to humans from the H5N1 virus in Asia? : 

What is the risk to humans from the H5N1 virus in Asia? In 1997, the first case spread from a bird to a human was seen during an outbreak of bird flu in poultry in Hong Kong. The virus caused severe respiratory illness in 18 people, 6 of whom died. Since that time, there have been other cases of H5N1 infection among humans. Most recently, human cases of H5N1 infection have occurred in Thailand, Vietnam and Cambodia during large H5N1 outbreaks in poultry. The death rate for these reported cases has been about 50 percent. Most of these cases occurred from contact with infected poultry or contaminated surfaces; however, it is thought that a few cases of human-to-human spread of H5N1 have occurred.

What is the risk to humans from the H5N1 virus in Asia? : 

What is the risk to humans from the H5N1 virus in Asia? So far, spread of H5N1 virus from person to person has been rare and spread has not continued beyond one person. However, because all influenza viruses have the ability to change, scientists are concerned that the H5N1 virus could one day be able to infect humans and spread easily from one person to another. Because these viruses do not commonly infect humans, there is little or no immune protection against them in the human population. If the H5N1 virus were able to infect people and spread easily from person to person, an influenza pandemic (worldwide outbreak of disease) could begin. No one can predict when a pandemic might occur. However, experts from around the world are watching the H5N1 situation in Asia very closely and are preparing for the possibility that the virus may begin to spread more easily and widely from person to person.

Three levels of H5N1 transmission: 

Three levels of H5N1 transmission Intercontinent--transport live poultry, frozen poultry meat, untreated hatching eggs, poultry by-products over long distances--free living migrating birds. International--trade of commercial poultry including live birds, crates, vehicles, containers, international exhibitions, shows, bird markets--birds that display seasonal migration patterns. Local--farm personnel, contaminated poultry manure & waste stuff, airborne particles & dust--birds living in close vicinity to people.

How is infection with H5N1 virus in humans treated?: 

How is infection with H5N1 virus in humans treated? The H5N1 virus currently infecting birds in Asia that has caused human illness and death is resistant to amantadine and rimantadine, two antiviral medications commonly used for influenza. Two other antiviral medications, oseltamavir and zanamavir, would probably work to treat flu caused by the H5N1 virus, though studies still need to be done to prove that they work.

Is there a vaccine to protect humans from H5N1 virus? : 

Is there a vaccine to protect humans from H5N1 virus? There currently is no vaccine to protect humans against the H5N1 virus that is being seen in Asia. However, vaccine development efforts are under way. Research studies to test a vaccine to protect humans against H5N1 virus began in April 2005. (Researchers are also working on a vaccine against H9N2, another bird flu virus subtype.)

Slide31: 

Cumulative number of confirmed human cases of avian influenza A(H5N1) reported to WHO since 2003 (28 June 2005) country official cases/deaths unofficial cases/death Vietnam 87/38 91/40 Thailand 17/12 17/12 Cambodia 4/4 4/4 TOTAL 108/54 113/56

Latest news: 

Latest news May 13 Avian flu case reported in Vietnam/WHO denies that countries hoard H5N1 samples May 17 Vietnamese find another case of avian flu May 18 WHO: flu pandemic threat may be growing May 19 WHO raises avian flu case count to 97 May 23 Vietnamese dies of avian flu; China has cases in wild geese May 24 WHO updates rules to prevent spread of disease May 27 Indonesian pigs have avian flu virus; bird cases double in China June 3 China plans early warning system for avian flu June 10 WHO calls H5N1 flu “unpredictable; seeks China field visit June 14 Human trial of H5N1 vaccine prompts concern, Australia touts poultry test June 15 Indonesia confirms human case of H5N1; 6 more people ill in Vietnam June 17 WHO logs four more avian flu cases in Vietnam June 20 China’s alleged use of human flu drug in poultry questioned

Latest news: 

Latest news June 21 Avian flu infects two more Vietnamese, hits poultry in China June 24 Experts study behavior of H5N1 virus in Vietnam, China June 27 Japan has H5N2 avian flu outbreak June 28 Flu kills more migratory birds in China June 29 H5N1 virus has not grown more dangerous, experts say June 30 WHO says pandemic risk unchanged; Fatal H5N1 case reported in Vietnam July 5 Global health agencies have plan to fight avian flu July 6 Wild birds could spread H5N1 virus beyond Asia, reports say July 7 Avian flu control plan to focus on small farms July 8 First avian flu in Philippines July 11 Thailand has first avian flu outbreaks in 3 months July 14 Another avian flu death reported in Vietnam and 3 more people infected July 15 Avian flu suspected in 3 deaths in an Indonesian family-a man and his 2 daughters who had no contact with poultry

What does CDC recommend regarding the H5N1 bird flu outbreak in Asia?: 

What does CDC recommend regarding the H5N1 bird flu outbreak in Asia? In February 2004, CDC provided U.S. health departments with recommendations for enhanced surveillance (detection) in the U.S. of avian influenza A (H5N1). Follow-up messages (Health Alert Network) were sent to the health departments on August 12, 2004, and February 4, 2005, both reminding health departments about how to detect, diagnose, and prevent the spread of avian influenza A (H5N1). It also recommended measures for laboratory testing for H5N1 virus. CDC currently advises that travelers to countries in Asia with known outbreaks of influenza A (H5N1) avoid poultry farms, contact with animals in live food markets, and any surfaces that appear to be contaminated with feces from poultry or other animals.

H5N1 virus as a biological weapon: 

H5N1 virus as a biological weapon Extremely contagious High mortality rate Severe economic consequences of an outbreak Virus has a high potential for genetic mutations and for new strains to arise and affect new species

Directions for future research: 

Directions for future research How does the avian flu impact economies, societies, and cultures in South East Asian countries? How do western-based public health strategies to control avian flu affect indigenous cultures in South East Asia? What are some locally-based public health strategies to control avian flu? What are the interactions between western-based and locally- based public health practices to control avian flu?

Student discussion questions: 

Student discussion questions Growing numbers of animal and human cases of bird flu in Asia are causing concern among health officials. What is avian flu and, what are the possible risks to humans? Is the Avian flu the next pandemic? Some dissentient public health officials state that the World Health Organization (WHO) response to the H5N1 Avian Influenza is based on fear tactics that are unfounded and, cause unnecessary economic, social, and environmental burdens on people and places. Do you agree or disagree with WHO’s “alarm “ tactics to this virus? What should be US Center to Disease Control (CDC) response to the H5N1 Avian Influenza? What are implications of the H5N1 Avian influenza for SEAsian countries, cultures, and people? Conservative estimates are that by the end of 2005, SEAsian countries affected by the avian flu have economic losses of $130 billion. SEAsian countries like Vietnam and Cambodia are jointly asking for monetary relief of $120 million from wealthy countries like the US. Should the US and other wealthy countries give $120 million in relief funds to avian flu affected SEAsian countries?

References: 

References US Center for Disease Control (CDC): www.cdc.gov/flu/avian World Health Organization (WHO): www.who.int/csr/disease/avian_influenza British Broadcasting Corporation (BBC): www.news.bbc.co.uk/2/hi/science/nature University of Minnesota Center for Infectious Disease Research & Policy (CIDRAP): www.cidrap.umn.edu/cidrap/content/influenza/avianflu European Commission on-line (EUROPA): www.europa.eu.int/comm/food/animal/ diseases/controlmeasures/avian Nature Magazine: www.nature.com/nature/focus/avianflu New York Times: www.nytimes.com