The flu ... and you.
When your coworker or a patient is coughing, sneezing and blowing their nose, do you wonder, "Are Standard Precautions enough?" Many people are not sure how much of a threat influenza is, how to identify people with the flu, and what action to take if a member of the dental team or a patient is contagious. News of deadly new strains of influenza, such as the "bird flu," is a worldwide concern. In addition, a dental office should be safe and clean, so that even highly susceptible patients or workers are protected. This course will describe seasonal and avian influenza, suggest how to recognize flu, and present facts about prevention and treatment of both "bird flu" and the more certain occurrence of seasonal flu.
Upon completion of this course the dental professional should be able to:
* Understand the general biology of influenza.
* Compare past and present epidemic and pandemic threats.
* Explain flu transmission and suggest methods to prevent transmission.
* Recognize signs and symptoms of influenza and health risks.
* Summarize considerations for vaccinations and antiviral treatment.
* Take appropriate precautions against influenza exposure.
* Discuss and practice Respiratory Hygiene/ Cough Etiquette.
* Follow CDC Recommendations for workers with influenza.
II. Course Objectives
III. Course Outline
V. Background of Influenza
VI. Flu Biology: A New Flu Every Year
VII. Types of Influenza
VIII. Health Risks Associated with Influenza
IX. Clinical Signs and Symptoms of Influenza
XI. Prevention and Infection Control Measures
B. Avian Flu
C. Antiviral Medications
D. Respiratory Hygiene/Cough Etiquette
E. Masking and Separation of Persons with Respiratory Symptoms
F. Droplet Precautions for Influenza Transmission Control
G. If You Have Influenza Symptoms
H. Prevention of Avian Flu
Background of Influenza
Influenza is an acute respiratory illness that spreads through populations yearly during the winter months. This infection is generally self-limiting in healthy people, but may be serious or deadly in susceptible individuals. Periodically new and very deadly strains of influenza appear, leading to epidemics and pandemics. Birds are natural hosts to all subtypes of influenza, and serve as a constantly moving, extensive reservoir of potentially dangerous flu viruses.
Asymptomatic, wild birds infected with mild or lethal influenza subtypes can transmit them to humans via intermediate animals such as domestic poultry and pigs. Live animal farms and markets, where animals are crowded together and species are commingled, provide the perfect environment for influenza viruses to be transmitted. Infected birds and animals transmit influenza directly when in close contact, indirectly through secretions and excretions (which remain stable in the environment, especially in cold weather) or when eaten raw.
Historically, Asia has been recognized as the main source for epidemic and pandemic influenza, but until the present, outbreaks of highly pathogenic avian flu in poultry were relatively rare. Since 1959 there have been 24 outbreaks, with 14 occurring in the last decade; most had limited distribution.
Flu Biology: A New Flu Every Year
Because the virus continues to mutate, it poses a new threat each year. If the change is slight, immunity developed from previous exposure may give some protection against the new altered virus. Influenza RNA contains 8 segments. It changes by genetic mutation or reassortment during viral replication. Antigenic drift refers to successive small point mutations that occur with successive replication. These changes may cause new subtypes capable of causing epidemics. Antigenic shift is a major and abrupt genetic reassortment, made possible when two subtypes exchange genetic material. This occurs when a single host is infected with two or more subtypes at once. The resulting new variants, or subtypes, are potentially very dangerous because they are completely unrecognized by host immune systems. They are able to infect many animals or humans and spread rapidly, leading to epidemics or pandemics.
Types of Influenza
There are three types of influenza. Type A is the most diverse and infects many animals, including ducks, chickens, pigs, whales, horses, and seals. While certain subtypes are found in specific animal hosts, birds are hosts to all subtypes of influenza A and are a repeated source of new flu pathogens. Type A is likely to undergo an antigenic shift if two or more subtypes infect a single host, creating new subtypes based on surface antigens hemagglutinin (H) and neuraminidase (N). Type A causes both epidemics and pandemics.
The earliest recognized pandemic of avian flu occurred in 1580 and there have been 31 since then. In 1918-1919, Spanish influenza A (H1N1) pandemic started in Kansas and spread worldwide through United States troops and steamship travel. In less than 5 months, 21 million people died. The pandemic claimed 500,000 U.S. lives and killed 50 million worldwide (2% of those infected died). In 1957-1958 the "Asian Flu" [A (H2N2)] killed 70,000 Americans, and the 1968-69 Hong Kong Flu [A (H3N2)] caused 34,000 U.S. deaths.
Typically an avian flu virus first infects pigs, then humans. The Hong Kong strain may have jumped directly from birds to humans, and the avian flu being spread today--"bird flu" or influenza A (H5N1)--is easily spread between birds but so far, rarely spreads from birds to humans and does not spread easily between humans. The virus is readily transmitted from farm to farm on contaminated shoes, clothing, vehicles, equipment, feed, and cages. This highly pathogenic virus can survive on surfaces for more than a month in cold temperatures, and weeks in warmer temperatures. For unknown reasons, most human cases of A (H5N1) have been in rural farms with small flocks rather than in presumed higher risk groups such as poultry markets.
Type B influenza infects only humans, primarily children, and generally causes milder disease than type A. Type B is known to cause seasonal outbreaks and epidemics, but not pandemics.
Influenza A (H1N1) and (H3N2) and Influenza B have circulated globally in humans since 1977. In 2001, A (H1N2) emerged and spread globally. It probably resulted from genetic reassortment of A (H1N1) and A (H3N2) when both viruses were present in one host. A (H5N1) is the current avian flu that is spreading globally in birds and is deadly to humans.
Type C influenza is common in swine, but rarely seen in humans.
Health Risks Associated With Influenza
Influenza is not a cold. The virus infects the lungs and can lead to pneumonia and more dangerous problems, especially in young children under two years of age, the elderly, and the immunocompromised. The three main health threats from influenza are (1) viral pneumonia or secondary bacterial pneumonia and death in susceptible people, (2) epidemics, and (3) less frequent but more deadly and widespread pandemics.
Influenza infects about 26% of the U.S. population every year. Twenty-five percent of health care workers develop influenza every year. More than 200,000 people are hospitalized and 36,000 die each year of the flu and its complications, including pneumonia, and worsening of chronic illnesses such as asthma, congestive heart failure, or diabetes. More than 90% of recorded flu deaths were in people 65 years old or older.
In humans, influenza A (H5N1) has a mortality rate of 64%, with most victims being previously healthy young adults or children. In contrast, the Spanish Flu of 1918-19 had a mortality rate of 2%. As of February 2006,165 people have been infected worldwide with A (H5N1) and 88 have died. Deaths have been reported in Vietnam (42), Indonesia (16), Thailand (14), Cambodia (4), Turkey (4), and Iraq (1). There have been no reported cases in the United States. People most likely to be infected are those who have close contact with infected birds, including bird blood and secretions. Almost all victims had direct or indirect exposure to infected birds. Health care workers who care for infected people and anyone in close contact with infected people may be at risk and should take appropriate precautions.
Experts are very concerned that A (H5N1) is spreading rapidly worldwide along migratory bird flyways. It also may spread among domestic poultry. This subtype has the ability to evolve and spread between people and to become the next deadly influenza pandemic.
Clinical Signs and Symptoms of Influenza
Symptoms of influenza typically include sudden onset of fever between 104[degrees] F-106[degrees] F (days 1-3), body/muscle aches, headache, extreme tiredness, dry cough, sore throat and nasal/sinus congestion and discharge (days 2-7). Cervical adenopathy is more common in children. Complications can include bacterial pneumonia, dehydration, and worsening of chronic medical conditions such as heart failure, asthma or diabetes. Children usually have a sinus and ear infection at the same time. Seasonal flu may result in death in the elderly, the very young, and the immunocompromised.
Birds can carry A (H5N1) without symptoms, with mild symptoms such as ruffled feathers and/or respiratory secretions, or suffer deadly systemic bleeding and death within 48 hours. It has earned the nickname "chicken ebola" from these more drastic symptoms. In humans, after an incubation period of 2 to 17 days, the most frequent symptoms are fever, eye infections, cough and x-ray evidence of pneumonia, though some have no respiratory symptoms. Clinical deterioration is rapid. About 33% have diarrhea and/or vomiting, and 70% have acute respiratory distress syndrome, and bleeding from the gingiva and nose have been reported. The overall mortality rate is 64% to 80% for those under 15 years of age. Death is caused by the flooding of lung tissues with fluid along with lung tissue destruction.
Flu is primarily transmitted via large and small virus-laden droplets that are generated when an infected person talks, sneezes, coughs or when spray-producing procedures such as dentistry are performed. These particles are usually larger than 5 microns ([micro]m) and settle on surfaces within 3 feet of the source-person or on the nasal surfaces of susceptible people who are within 3 feet. Direct contact or indirect contact with respiratory secretions will also transmit the flu, for example, touching surfaces or items contaminated with the virus and then touching the eyes, nose or mouth. Adults shed the virus and are infective from the day before symptoms begin to approximately 5 days after symptoms start. Children are infective longer: for 10 or more days, and young children can shed flu virus several days before symptoms begin. Severely immunocompromised people can continue to shed the virus (remain infective) for weeks or months.
Flu virus is relatively stable, especially in low humidity and cool temperatures.
Avian flu is transmitted by ingesting or by direct or indirect contact with nasal secretions, excretions and blood of infected birds. Some cultures are highly exposed because of customs or practices involving use of, or contact with these infective bird materials.
Prevention and Infection Control Measures
Vaccination is the best way to prevent flu infection. Researchers monitor circulating flu to predict the most likely strains to appear the next year, and prepare vaccines based on that prediction. There are two kinds of vaccinations:
* The "flu shot" is an inactivated virus. It is approved for people over 6 months old.
* The nasal-spray is a Live Attenuated Influenza Vaccine (LAIV). It is approved for healthy people over five years to 49 years of age who are not pregnant.
* October or November is the best time to get vaccinated.
Who Should Get Vaccinated?
* All children between 6 months and 23 months of age
* People 50 years or older
* People housed in long-term care facilities
* People 6 months and older with chronic heart or lung conditions including asthma, metabolic diseases or weak immune systems
* People on long-term aspirin therapy
* Women pregnant during the flu season
* Anyone in contact with susceptible people
CDC 2005 Influenza Recommendation Updates:
1. Persons with any condition that compromises respiratory function or management of respiratory secretions that may increase risk of aspiration should be vaccinated.
2. All health care workers should be vaccinated annually, and their employers are encouraged to provide and facilitate vaccinations.
3. Both available vaccines (inactivated and live attenuated) are recommended for eligible persons as appropriate, with inactivated vaccines preferred for high-risk groups.
4. Specific vaccine composition and availability will be continually monitored by CDC.
The flu shot is considered safe for pregnant women in the 2nd and 3rd trimester, and for breastfeeding mothers, but is NOT recommended for those with severe allergy to chicken eggs. Always consult a physician before being vaccinated.
Avian Flu [A (H5N1)]
Prevention measures in birds begin with culling (separating and killing) infected birds or birds possibly infected with A (H5N1). In 1997, Hong Kong's entire poultry population (estimated at 1.5 million birds) was destroyed, possibly preventing an A (H5N1) epidemic. Now a bird vaccine is in use for domestic poultry where available.
Prevention vaccinations are not available for humans yet. In January 2006, researchers in Pittsburgh, Pa., announced a very promising vaccine that is genetically engineered out of human cold virus and is 100% effective against A (H5N1) in mice and chickens. The vaccine can be produced very rapidly in lab dishes rather than needing fertilized chicken eggs. Human trials are planned to begin in February 2006.
There are four prescription antiviral medications available in the U.S., classified in two different categories. Adamantane derivatives (Anantadine and Rimantadine) have already been shelved as flu preventives and/or treatments because the 2005-2006 flu strains are resistant to them. Neuraminidase inhibitors (Zanamivir and Oseltamivir) as of this writing, are still active against both Type A and B influenza.
Zanamivir (Relenza[R]) by Glaxo SmithKline is an inhaled powder approved for treatment of flu in people seven years and older. Oseltamivir (Tamiflu by Hoffman-LaRoche) is a capsule or oral suspension approved for treatment of flu in people one year and older and a flu preventive (chemoprophylaxis) in persons 13 years and older.
Both of the remaining effective drugs (Relenza[R] and Tamiflu[R]) should be administered within 48 hours of illness onset and taken for 5 days. It is often difficult, however, to obtain a definite flu diagnosis within the first 48 hours.
Limited evidence suggests that oseltamivir (Tamiflu[R]) can improve survival rates in avian flu [A (H5N1)] if administered within 48 hours of symptom onset. Increased doses and longer administration time have also been suggested.
Respiratory Hygiene/Cough Etiquette
Respiratory Hygiene/Cough Etiquette should be incorporated into Standard Precautions to prevent transmission of all respiratory infections, including influenza. Implement the following infection control measures at the first point of contact with patients.
1. Visual Alerts
* Post visual alerts instructing patients and other visitors to:
--inform health care personnel if they have symptoms of respiratory infection when they first register.
--practice Respiratory Hygiene/Cough Etiquette.
2. Respiratory Hygiene/Cough Etiquette
* Cover the nose/mouth when coughing or sneezing.
* Use tissues to contain respiratory secretions and dispose of them in the nearest waste receptacle after use.
* Perform hand hygiene after having contact with respiratory secretions and contaminated objects/ materials: wash hands with non-antimicrobial or antiseptic soap and water, or use waterless alcoholbased hand rub.
3. Health care facilities should ensure the availability of materials for adhering to Respiratory Hygiene/ Cough Etiquette in reception areas.
* Provide tissues and no-touch receptacles for used tissue disposal.
* Provide alcohol-based hand rubs in common areas and reception rooms.
* Ensure that supplies for handwashing (i.e., soap, disposable towels) are consistently available at sinks.
Masking and Separation of Persons with Respiratory Symptoms
During flu season and times when community outbreaks of respiratory infections occur, offer masks to persons who are coughing. Either ear loop masks or surgical tie masks may be used to contain respiratory secretions. Respirators (N-95 or above) are not necessary for this purpose. Encourage coughing persons to sit at least 3 feet away from others in common areas. It may be easier to implement if this recommendation is used year-round.
Advise health care personnel to observe droplet precautions in addition to standard precautions when examining a patient with symptoms of a respiratory infection, particularly if a fever is present. Maintain precautions until cause of symptoms is determined not to require droplet precautions.
Droplet Precautions for Influenza Transmission Control
* Place patients in private rooms. Special air handling systems and ventilation are not necessary and the door may remain open.
* Health care personnel should wear masks when working within 3 feet of the patient. * Note: no studies have definitively shown that mask use by either infectious patients or health care personnel prevents influenza transmission.
* Patient Transport: Only transport patient out of private room when essential. Mask patient if possible when transporting.
If You Have Flu Symptoms
1. First, notify office safety manager.
2. Consider restriction from work to protect workers and patients, especially susceptible patients.
3. Observe droplet precautions.
4. Limit contact with other health care workers and patients.
5. Cover mouth when coughing or sneezing.
6. Wash your hands after contact with your respiratory secretions.
Prevention of Avian Flu [A (H5N1)]
Avoid contact with wild birds. Do not handle sick or dead birds. When traveling in countries where A (H5N1) is present, avoid poultry farms, animals in live food markets, and any surfaces that appear to be contaminated with feces from poultry or other animals. Do not eat raw bird meat, blood, or fluids and be careful handling or cooking poultry.
Patients with known or suspected avian flu infection should be given life-saving medical treatment in specially designed medical facilities using standard, contact and respiratory precautions and eye protection.
Seasonal influenza is primarily an upper respiratory illness that recurs yearly in slightly different forms. The "flu shot," or yearly vaccine, is the best precaution for preventing flu. All health care workers at risk are advised to be vaccinated every year. Occasionally more dangerous or even deadly forms develop, possibly leading to epidemics and pandemics. Both type A and B can cause epidemics, but influenza type A has greater potential to develop new and deadly subtypes and is responsible for the current "bird flu" that threatens to mutate to a form capable of a human pandemic.
The flu is spread by droplets of oral and respiratory secretions. In dental facilities, in addition to Standard Precautions, Droplet Precautions should be observed when people with highly contagious respiratory infections such as influenza are present. Consistent use of masks and careful hand hygiene, including use of alcohol-based waterless agents in both treatment and public areas by both employees and patients, are the most important precautions to control influenza. CDC Respiratory Hygiene/Cough Etiquette (available in posters from the CDC) is the perfect starting point to inform workers and patients how to keep the dental office "a safe place to be healed" rather than a place to contract the flu.
asymptomatic--A condition without symptoms.
Avian Flu- Influenza type A (H5N1) a subtype of influenza type A that was identified in 2003 and continues to infect birds. A (H5N1) has infected humans, who appear to have contracted it directly from infected birds. This subtype has the potential to cause a human pandemic if it mutates to a form that can be passed easily between humans.
bird flu- Influenza A types that primarily infect birds, but can infect humans.
chicken Ebola--Nickname for highly pathogenic avian influenza that causes internal hemorrhaging and rapid death. droplets- Respiratory and oral particles larger than 5 microns in diameter generated by coughing, sneezing, talking, or by splatter-producing procedures, such as dentistry.
flu--A commonly used term for influenza. highly pathogenic avian influenza--A very contagious, fatal influenza that progresses very rapidly. It is found primarily in bird populations, but may be spread to other species, including humans. First identified in Italy in 1878, it can kill within 48 hours with 100% mortality.
influenza epidemic--A widespread, rapid transmission of influenza infection throughout a population.
influenza pandemic--A worldwide spread of a new subtype or one that has not circulated among humans for a long time. People do not have immunity to the pathogen, so it causes severe infection, illness and death. Influenza pandemics result from Influenza A undergoing antigenic shift, creating a new virus capable of being transmitted between humans. Influenza pandemics arise at regular intervals.
pathogen--An agent that causes disease.
Standard Precautions--A term used in infection control to identify a standard of care in which all blood or any other body fluid, excretion, or secretion (except sweat) and non-intact skin or mucous membranes, regardless of whether they contain blood, are treated as infectious.
To order posters: http://www.cdc.gov/flu/professionals/flugallery/ posters.htm Prevention and Control of Influenza, MMWR July 29, 2005/Vol 54/No. RR-8, p.2.
Key Facts about Influenza and Influenza Vaccine. Department of Health and Human Services, Centers for Disease Control and Prevention, Sept. 28, 2005.
WHO Avian influenza ("bird flu")--Fact Sheet Jan. 2006 http://www.who.int/csr/disease/avian_influenza/avianinfluenza_factsheet Jan2006/3n/print.html
Guidelines for Infection Control in Dental Health Care Settings--2003, Centers for Disease Control MMWR Dec. 19, 2003/52(RR17);1-61.
Fighting the Flu. John A. Molinari, PHD. Dimensions of Dental Hygiene Jan. 2005, pp. 22-26.
The Implications of Influenza. John A. Molinari, PHD. Dimensions of Dental Hygiene Feb. 2005, pp. 22-24.
Influenza (Flu)/Primary Changes and Updates in the 2005 Recommendations, Department of Health and Human Services, Centers for Disease Control and Prevention, August 8, 2005. http://www.cdc.gov/flu/professionals/vaccination/primarychanges.htm
Inactivated Influenza Vaccine--What You Need to Know. Department of Health and Human Services, Centers for Disease Control and Prevention, July 18, 2005.
Prevention and Control of Influenza: Recommendations of the Advisory Committee in Immunization Practices (ACIP) (MMWR 29 July 2005;54[RR)*]:1-40).
Fact Sheet: Influenza Symptoms, Protection, and What to Do If You Get Sick. Department of Health and Human Services, Centers for Disease Control and Prevention, January 14, 2006.
Droplet Precautions, Guideline for Isolation Precautions in Hospitals, Department of Health and Human Services, Centers for Disease Control and Prevention, http://www.cdc.gov/ncidod/dhqp/ gl_isolation_droplet.html
Interim Guidance for the Use of Masks to Control Influenza Transmission. Department of Health and Human Services, Centers for Disease Control and Prevention, August 8, 2005.
Influenza Antiviral Medications: 2004-05 Interim Chemo-prophylaxis and Treatment Guidelines. November 3, 2004. Department of Health and Human Services, Centers for Disease Control and Prevention.
Evidence Mounts for Shelving Two Flu Drugs. Michael Smith, MedPage Today Staff Writer, Zalman S. Agus, MD: http://www.medpagetoday.com accessed 2/7/2006.
Fact Sheet: Antiviral Agents for Influenza: Background Information for Clinicians. Department of Health and Human Services, Centers for Disease Control and Prevention. Dec. 16, 2003.
Transmission of Influenza A Viruses Between Animals and People. Department of Health and Human Services, Centers for Disease Control and Prevention http://www.cdc.gov/flu/ avian/gen-info/transmission.htm
Influenza Vaccine Information for Health Care Personnel. Department of Health and Human Services, Centers for Disease Control and Prevention http://www.cdc.gov/ncicoc/hip/flu_vac.htm
Respiratory Hygiene/Cough Etiquette Resources
* Respiratory Hygiene/Cough Etiquette www.cdc.gov/flu/professionals/infectioncontrol/resphygiene.htm
* Notice to Patients to Report Flu Symptoms www.cdc.gov/ncidod/dhqu/pdf/Infdis/RespiratoryPoster.pdf Emphasizes covering coughs and sneezes hand hygiene
* Cover Your Cough www.cdc.gov/flu/protect/covercough.htm Tips to prevent the spread of germs from coughing
* Information about Personal Protective Equipment www.cdc.gov/ncidod/dhqp/ppe.html Demonstrates the sequences for donning and removing personal protective equipment
THE FLU...AND YOU POST-TEST
Choose the one best answer.
1. Influenza is usually acute, but can become chronic.
2. Flu Epidemics occur because
a. influenza viruses mutate during replication, introducing new, perhaps deadly, viruses
b. mutations bring forth new flu subtypes that people do not have immunity to
c. there are mechanisms for widespread flu transmission and many susceptible people
d. All of the above
3. A symptom of influenza typically includes a fever of
a. 98.6[degrees] F--99.6[degrees] F
b. 104[degrees]F- 106[degrees] F
c. 102[degrees]F- 103[degrees]F
d. 100[degrees] F
e. no fever associated
4. A major shift in genetic material, likely to occur when two viral types infect the same host, is
a. genetic drift
b. common in pigs and possible in humans
c. antigenic shift
5. Flu-laden particles or droplets generated while coughing, sneezing or doing dentistry are thought to usually
a. be larger than 5 microns
b. be smaller than 5 microns
c. require fit-tested respirators
d. require procedure or surgical masks
6. Dental workers should be vaccinated
a. with either the "flu shot" or nasal spray
b. only the "flu shot"
c. only nasal spray (Live Attenuated Influenza Vaccine)
d. every other year
7. Respiratory Hygiene/Cough Etiquette refers to:
a. saying "excuse me" to warn others of a cough
b. coughing away from others
c. covering one's cough and washing hands or using alcohol hand sanitizer afterward
d. wearing a fit-tested respirator when you have a cough
8. Influenza type A (H5N1) has killed people in the United States.
9. Symptoms of seasonal flu may include
a. sudden fever
b. muscle aches
c. sore throat
d. sinus congestion
e. All of the above
10. Avian influenza Type A (H5N1)
a. is widespread in birds and pigs
b. is spreading currently through the bird populations
c. has extremely low chance of becoming a human pandemic
d. is primarily threatening humans, with birds showing no symptoms
Nancy Andrews is a dental consultant, national speaker and author. She can be reached at email@example.com.
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|Title Annotation:||free course on influenza for dental professional|
|Publication:||The Dental Assistant|
|Date:||Mar 1, 2006|
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