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Infectious diseases: Preparing for winter

Oct. 1, 2011
This winter, make a commitment to stay healthy. If you understand how you get infected with a cold, the flu, or other infectious diseases, you can employ strategies to avoid getting sick.

by Leslie Canham, CDA, RDA

This winter, make a commitment to stay healthy. If you understand how you get infected with a cold, the flu, or other infectious diseases, you can employ strategies to avoid getting sick. Dental health-care providers (DHCP) have a responsibility when it comes to preventing the spread of infectious diseases in the dental setting, not only with regard to sterilization and disinfection, but also with regard to the transmission of infectious diseases via hands, surfaces, and close contact with patients.

DHCP are also responsible for monitoring their health status. If they have acute or chronic medical conditions that render them susceptible to opportunistic infection, they should discuss with their personal physician or another qualified authority whether the condition might affect their ability to safely perform their duties.1

How do I know if I have a cold or the flu?

The common cold and the flu are both caused by viruses and have similar symptoms, with the flu being worse than a cold. Flu-like symptoms include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills, and fatigue. Some people may also have vomiting and diarrhea. People may be infected with the flu and have respiratory symptoms without a fever. These symptoms can last for up to two weeks.

Colds generally do not result in serious health problems such as pneumonia, bacterial infections, or hospitalizations. On the other hand, the flu, a contagious respiratory illness, can cause mild to severe illness, and at times can lead to death. Because cold and flu symptoms are very similar, it can be difficult to tell whether you have a cold or the flu based on symptoms alone. If it is necessary to determine whether a person has a cold or the flu, special tests can be performed during the first few days of the illness.

What causes colds?

There are over 200 different viruses that can cause the common cold, the most common being rhinovirus. When germs that cause colds first infect the nose and sinuses, the nose makes clear mucus. This helps wash the germs from the nose and sinuses. After two or three days the body’s immune cells fight back, changing the mucus to white or yellow. As the bacteria that live in the nose grow back, they can also be found in the mucus, which changes to a greenish color.2

How does flu spread?

Most experts believe that flu viruses spread mainly by droplets when people with the flu cough, sneeze, or talk. These droplets can land in the mouths or noses of people nearby. Less frequently, people might also get the flu by touching a surface or object that has flu virus on it and then touching their mouth, eyes, or nose.

You may be able to pass the flu on to someone before you know you’re sick, as well as while you’re sick. Most adults may be able to infect others beginning one day before symptoms develop, and up to five to seven days after becoming sick. Some people, especially young children and people with weakened immune systems, might be able to infect others for an even longer time. 3

Seasonal flu — In the United States, seasonal influenza refers to the periodic outbreaks of respiratory illness in the fall and winter. Outbreaks are typically limited and most people have some immunity to the circulating strain of the virus. A vaccine prepared in advance of the influenza season is designed to match the influenza viruses most likely to be circulating in a community.

Influenza pandemic — In 2009, OSHA published guidelines for employers to prepare workplaces for an influenza pandemic. In the publication, OSHA defines a pandemic as a global disease outbreak. An influenza pandemic occurs when a new influenza virus emerges for which there is little or no immunity in the human population, and causes serious illness that spreads easily from person to person worldwide. A worldwide influenza pandemic could have a major effect on the global economy, such as travel, trade, tourism, food consumption, and eventually investment and financial markets. It is essential that business and industry plan for an influenza pandemic in order to minimize a pandemic’s impact.4

In the guidelines, OSHA indicated that in the event of a pandemic, employers play a key role in protecting employees’ health and safety, as well as limiting the impact on the economy and society.

H1N1 swine flu — In the spring of 2009, a new flu virus spread across the United States and the world. Swine flu is a respiratory disease in pigs caused by type A influenza viruses that regularly cause outbreaks of influenza in pigs. The classical swine flu virus (an influenza type A H1N1 virus) was first isolated from a pig in 1930. The 2009 H1N1 influenza virus (referred to as swine flu early on) was first detected in people in the U.S. in April 2009. This virus was originally referred to as swine flu because laboratory testing showed that its gene segments were similar to influenza viruses that were most recently identified in and known to circulate among pigs.

The Centers for Disease Control and Prevention (CDC) believes that this virus resulted from reassortment, a process through which two or more influenza viruses can swap genetic information by infecting a single human or animal host. When reassortment occurs, the virus that emerges will have some gene segments from each of the infecting parent viruses and may have different characteristics than either of the parental viruses, just as children may exhibit unique characteristics that are like their parents.

In this case, the reassortment appears to have occurred between influenza viruses circulating in North American pig herds and Eurasian pig herds. Reassortment of influenza viruses can result in abrupt, major changes in influenza viruses, known as “antigenic shift.” When shift happens, most people have little or no protection against the new influenza virus.5

According to the World Health Organization, by June of 2010, more than 214 countries and overseas territories or communities had reported laboratory confirmed cases of pandemic influenza H1N1 2009, and there were 18,209 deaths reported. The number of fatal cases is an under representation of the actual numbers, as many deaths are never tested or recognized as influenza-related. Centers for Disease Control and Prevention estimates that between 43 million and 89 million cases of 2009 H1N1 occurred between April 2009 and April 2010.

The most severe recorded outbreak of the flu was the Spanish flu of 1918 and 1919. During this pandemic, more than 21 million people died worldwide, with over 500,000 deaths in the United States.

Flu seasons are unpredictable and can be severe. In the United States every year, 5% to 20% of the population gets the flu, more than 200,000 people are hospitalized from seasonal flu-related complications per year, and the CDC estimates 36,000 flu-associated deaths per year.

The recent 2009 H1N1 pandemic could have been a lot worse. But the general public was informed about H1N1 within weeks of the first U.S. case, vaccinations were made available as quickly as possible, and people followed the guidelines issued by public health agencies.

CDC says “Take 3” actions to fight the flu

Action 1, get vaccinated: CDC recommends an annual flu vaccination as the first and most important step in protecting against the flu. Even if you vaccinated with the 2010-2011 flu vaccine, you should get vaccinated again with the 2011-2012 vaccine as it will protect against an influenza A H3N2 virus, an influenza B virus, and the H1N1 virus. Everyone six months and older should get vaccinated against the flu as soon as the 2011-2012 season vaccine is available. Flu season can begin as early as October and last until May or later.

Action 2, take everyday preventive actions to stop the spread of germs. These actions include: cover your nose and mouth with a tissue when you cough or sneeze; throw the tissue in the trash after use; wash your hands often with soap and water; if soap and water are not available, use an alcohol-based hand rub; avoid touching your eyes, nose, and mouth because this is how germs spread; try to avoid close contact with sick people; if you are sick with a flu-like illness, CDC recommends that you stay home for at least 24 hours after your fever is gone; and while sick, limit contact with others as much as possible to keep from infecting them.

Action 3, take flu antiviral drugs if your doctor prescribes them. Antiviral drugs are different from antibiotics. They are prescription medicines (pills, liquid, or an inhaled powder) and are not available over-the-counter. Antiviral drugs can make illness milder and decrease the time you’re sick. They may also prevent serious flu complications.

It’s very important that antiviral drugs be used early (within the first two days of symptoms) to treat people who are very sick (such as those who are hospitalized) or people who are sick with flu symptoms and at increased risk of complications, such as pregnant women, young children, people 65 and older, and people with certain chronic health conditions.6

Another important step hygienists can take is to make sure that the masks worn during patient care provide the appropriate level of protection.

The purpose of wearing a surgical mask is twofold. First, the mask protects the patient against microorganisms generated by the DHCP (with greater than 95% bacterial filtration efficiency). Secondly, the mask protects the dental health-care provider from large particle droplet spatter that might contain bloodborne pathogens or other infectious microorganisms.

Unless otherwise specified, the term facemask refers to disposable facemasks cleared by the U.S. Food and Drug Administration (FDA) for use as medical devices. This includes facemasks labeled as surgical, dental, medical procedure, isolation, or laser. Such facemasks have several designs.

The American Society for Testing and Materials (ASTM) evaluates masks according to five performance factors: fluid resistance, bacterial filtration efficiency, particulate filtration efficiency, differential pressure/breathability, and flammability.

Fluid resistance is the ability of the mask to prevent fluid from passing through to the wearer’s face. Bacterial filtration efficiency measures the size of bacterial cells that could pass through the mask to the wearer. Particulate filtration measures the efficiency of the masks to filter particles. Differential pressure/breathability measures the air pressure both inside and outside of the mask. Flammability measures how easily the mask can be ignited and burn.

How to choose a mask

Choosing a mask depends on the type of procedure and level of contamination anticipated. When performing procedures that generate high levels of aerosolized moisture, such as use of high-speed handpieces, air-water syringes, and ultrasonic scalers, an ASTM “high barrier” category mask should be used.

For procedures with low level of aerosolized moisture or particles, an ASTM “moderate barrier” mask can be used. For procedures with no aerosolized moisture or particles, such as oral exams or taking X-rays, an ASTM “low or primary barrier” mask can be used.

Non-ASTM masks do not meet the ASTM performance standards. These nonrated masks provide only a paper barrier as protection. Because nonrated ASTM masks offer the lowest level of protection for the wearer, they should not be worn for dental procedures where aerosolized moisture or particles are generated from the patient’s oral cavity, or when working with items contaminated with oral fluids.

Armed with information about how colds and the flu are spread, steps can be taken to protect yourself and your patients this winter.

The 2009 Swine Flu H1N1 timeline:
• April 15, 2009 — The first H1N1 case in the U.S., a 10-year old patient in California.
• April 26, 2009 — The U.S. government declares a public health emergency for H1N1 flu.
• June 11, 2009 — The World Health Organization (WHO) declares global H1N1 flu pandemic.
• June 19, 2009 — By this date, all 50 states in the U.S., the District of Columbia, Puerto Rico, and the U.S. Virgin Islands report cases of H1N1 flu.
• June 23, 2010 — The U.S. Public Health Emergency for H1N1 flu expires.
• August 10, 2010 — World Health Organization declares an end to the global H1N1 flu pandemic.

Leslie Canham, CDA, RDA, is a dental speaker and consultant specializing in infection control and OSHA compliance. Leslie is the founder of Leslie Canham & Associates, providing programs for associations and study clubs, in-office training, mock-inspections, consulting, and online webinars to help the dental team meet state and federal regulations. Leslie’s fast paced and entertaining programs have earned her the reputation as an outstanding speaker in dentistry. Leslie is recognized as a continuing education provider by the California Dental Board and is authorized by the Department of Labor as an OSHA Outreach Trainer in General Industry Standards. You can reach her at

1. Kohn WG, Collins AS, Cleveland JL, et al. Guidelines for infection control in dental health-care settings, 2003. MMWR Recomm Rep. 2003;52(RR-17):1-61. Web 17 Jul 2011. <>.
2. “Get Smart: Know When Antibiotics Work.” Centers for Disease Control and Prevention. N.p., 17JUL2011. Web. <>.
3. “Seasonal Influenza (Flu).” Centers for Disease Control and Prevention. N.p., 14JUL2011. Web. 17 Jul 2011. <>
4. United States Department of Labor, Occupational Safety and Health Division. (2009). Guidance on preparing workplaces for an influenza pandemic (OSHA 3327-02N 2007). Retrieved from <>
5. Centers for Disease Control and Prevention, Origin of 2009 h1n1 flu (swine flu). (2009, November 25). Retrieved from
6. “Seasonal Flu.” Centers for Disease Control and Prevention. N.p., 13JUL2011. Web. 17 Jul 2011. <>.

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