Severe acute respiratory syndrome (SARS) is the first new and readily contagious disease of the 21st century. The earliest SARS cases occurred in a province of southern China in November 2002. The outbreak was not recognized or announced until March 2003. Scientific evidence strongly points to what is called a coronavirus as the cause of SARS. Although several laboratory tests have been developed, there is no conclusive test for finding the presence of the coronavirus in humans at this time.
A diagnosis of SARS is based on certain symptoms of the disease and travel to an affected area or close exposure to a SARS patient. There is no specific treatment yet available for persons with SARS. Care is provided as needed to fight the effects of pneumonia or respiratory distress.
The symptoms of SARS include fever, cough, and difficulty breathing. The disease is spread through close contact. Close contact means having cared for, lived with or had face-to-face (within one metre) contact with a person with SARS. Close contact also means having had direct contact with respiratory secretions or body fluids of a person with SARS. From the time of exposure, it takes between two to ten days to develop signs of SARS illness. People are considered infectious once they develop fever or respiratory symptoms. From what has been seen with SARS so far, it appears that older people will develop more severe SARS illness than younger persons. Most people affected by SARS will recover after a brief illness, but about 10 per cent will die from health complications.
Global air travel had a major role in the rapid spread of SARS disease all across the world. Many countries are now using the quarantine act to try to prevent the disease from spreading further. Measures have been taken at airports to find persons with early symptoms of SARS. These people are not allowed to board an aircraft.
Currently, our only means to control the spread of SARS is to recognize it early, and use proper isolation and infection control measures. SARS is an example of how a new disease can emerge and spread in the global community in a very short period of time and illustrates the importance of maintaining a strong public health surveillance and response system.
Viruses are responsible for most respiratory infections, the most common being colds and influenza. The most frequent bacterial respiratory infection is Strep throat, caused by Group A streptococcus bacteria. Antibiotics are used to treat infections caused by bacteria. Antibiotics have no effect on infections caused by viruses, and should not be used in their treatment.
Prevention of Respiratory Infections
Though many different viruses and bacteria may be the cause, the same measures help fight the spread of respiratory infections.
A cold or upper respiratory infection is a viral infection with a runny nose and possibly a scratchy throat. It is passed through direct contact with someone already infected with a cold. There are as many as 200 viruses that cause colds. With repeated exposure it is possible to develop some immunity (resistance) over time. Most healthy children get at least six colds each year. Frequent colds in children are generally not a concern.
Currently there is no cure for the common cold. Over-the-counter drugs can help manage some of the symptoms. A fever is usually gone within three days and other upper respiratory symptoms disappear in a week. A cough may last for two to three weeks.
Complications from colds, such as ear infections or even pneumonia, are most common in children under 12 months of age. Infants can become dehydrated as a result of trouble breathing and sucking at the same time. Smaller airways in young children make them more at risk for breathing problems than older children or adults. The frequency of colds slowly lessens as children grow. By the time they enter school, children have about the same number of colds as adults.
Comparing Colds and Influenza (from the National Institute of Allergy and Infectious Disease)
|Fever||Rare||Common and high (38°C to 40°C) Lasts three to four days|
|Headache||Rare||Almost always present|
|General aches and pains||Mild||Often severe|
|Fatigue, exhaustion and weakness||Mild||Extreme exhaustion is early and severe. Fatigue and weakness can last for two to three weeks.|
|Stuffy nose||Nearly always||Sometimes|
|Chest discomfort and cough||Mild to moderate, hacking cough||Common, can be severe|
Influenza (the ‘flu’)
Do I need a flu shot?
The following people should have an influenza vaccine each year:
• Adults and children with chronic heart or lung illnesses (including asthma) severe enough to require regular medical follow-up or hospital care
• People of any age who live in nursing homes and other long-term care facilities
• People 65 years of age and older
• Adults and children with chronic conditions, including diabetes and other diseases of the metabolism, cancer, kidney disease, and problems with red blood cells (such as anemia) or with the immune system
• Children and adolescents (six months to 18 years of age) who have conditions treated for long periods with acetylsalicyclic acid (ASA, e.g. Aspirin™
• Those who will be traveling to places where the disease is likely to be present
The vaccine is also recommended for those who may pass influenza to those at high risk of influenza complications, including:
• health care workers, nursing home employees, and other personnel
• Household contacts (including children) of people at high risk who cannot have the vaccine or whose immune system may have an inadequate response to the vaccine
Note: ASA (acetylsalicylic acid, e.g. Aspirin™) and products that contain ASA are rarely recommended for persons under 18 years of age. Reye’s Syndrome is a very serious condition involving the liver and brain. It has been linked with ASA use in children who have viral infections, including influenza.
The influenza family has three main types; A, B, and C. Outbreaks of disease are due to Influenza A or Influenza B. Since these viruses change quickly, they can cause outbreaks each year. Circulating influenza viruses may change drastically at irregular intervals, usually ten years or more. A major shift can mean a worldwide epidemic.
An influenza epidemic typically strikes Canadians each year sometime between October and March. Influenza is a very important disease, due in part to the speed with which epidemics spread.
Symptoms are more severe and complications occur more often with influenza than with other viruses such as colds. The very young and the elderly are among those at highest risk of severe complications. People with certain long-term medical conditions affecting the immune (defence) system are also at high risk. Pneumonia is the most common complication of influenza. It generally develops about five days after the start of flu-like symptoms. Less common complications include cardiac (heart) disease, encephalitis (inflammation of the brain) and Reye’s Syndrome (an inflammation of the brain and liver). According to estimates, about one per cent of people with influenza must spend time in hospital.
A specific group of symptoms occur with influenza, including a severe cough (new or worse), fever, headache, sore throat, muscle aches, joint pain, and a complete lack of energy. Influenza can be identified in a lab by growing a specimen taken from the nose or throat, but this is not routinely done.
The best way to prevent influenza is to get an influenza vaccination or ‘flu shot’ every fall. Since the virus changes slightly every year, annual vaccinations are required. Some studies have found that improving vaccination rates in individuals results in a healthier community. Vaccination provides 70 to 100 per cent protection against influenza when the virus and vaccine are well matched. Vaccines may be slightly less effective in people whose immune system has a weaker response than that of healthy young adults.
The vaccine is injected into a muscle, usually in the arm. It is not recommended for people who are severely allergic to eggs or to thimerosal (a preservative which may also be found in contact lens solutions). Since the vaccine does not contain live virus, it is impossible to get influenza from an immunization. The injection site may be red and tender. Other side effects include mild fatigue, muscle aches and pains. In very few cases people have mild flu-like symptoms within the first 24 hours after vaccination. Symptoms generally occur between six and 12 hours after the vaccination and are gone within 48 hours.
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