Health Newsletter:May 2006
Related Links:| Avian Flu Flu Vaccine Influenza | Hepatitis A Hepatitis Vaccines Viral Infections | Life Expectancy Calories Reduction Metabolism | Blood Clots Vein Thromboses Blood Circulation | Peanut Allergies Allergies Asthma |
From WebHealth
Contents |
Avian Flu Needs Preparedness Instead Of Panic
Nobody can predict when the next pandemic will hit and whether it will be from an avian flu, but Canada and other countries are not taking any chances. The feds have commissioned a mock vaccine that can be adapted to whatever strain comes along. The Canadian Public Health Agency is also calling for alertness to patients coming back from countries where avian flu has occurred, especially countries with human cases. Canada is erring on the side of caution when it comes to the national flu pandemic preparedness plan. There is preparation for up to 138,000 people in need for hospitalization and between 11,000 and 58,000 death could occur. The economic impact is estimated between $ 10 and 24 billion.
It is true that public health agencies are worried, as three conditions for a possible pandemic are present: the viral strain is a new one, humans have no immunity to this new virus, and the strain is virulent.
The fourth condition would be that the strain could be spread from person to person. However this condition has not developed at this point. A lot of hype has gone through the press, misinformation is rampant, and as a result people are mixing up influenza preparedness with an avian flu pandemic. Anxiety runs high in the population. Some health professionals are already suffering from pandemic burnout before the virus has even landed, which is not a surprise: in the last few years warnings were sounded due to the outbreak of SARS. West Nile, Ebola, and Lassa fever have been other diseases that caused concern and anxiety. Before jumping to frightening conclusions that the avian flu will jump from person to person, it is important to see the facts in perspective. H5N1 at this point is not spread from person to person. The virus is transmitted from affected birds (chicken ducks, and other fowl) to humans, who have to be in close contact with the animal. The virus is found deep in the lungs of the infected person, and as a result it is more difficult to transmit than a virus that is found in mouth, nose or throat.
Human fatalities have occurred in Asia and the Middle East. Vietnam has had the highest number of deaths related to H5N1: 93 infections, 42 fatalities. Turkey has had 12 documented cases, four of them fatal.
In the meantime the world is not defenseless. Vaccines are in preparation, and vaccination trials are have been introduced in Vietnam. Work with horse antibodies is ongoing and the results are encouraging. Researchers in China developed a passive immunization by using horse antibodies. The advantage is the fact, that larger amounts of vaccine can be produced faster than with the culturing of the virus on eggs.
Public health agencies and health professionals are aware of the fact that pandemics have been around in the past. They are still a threat now. They agree that programs have to be in place to help mitigate the impact by doing the best they can. Disaster preparedness and alertness are definitely in order. Panic is not.
National Review Of Medicine, March 30, 2006, page 5.
Vaccinate Kids Against Hepatitis A
To vaccinate or to not vaccinate is often a point of dispute, especially if new vaccinations come into the forefront. Often the vaccinations have been used for a long time in areas where certain diseases were a threat to the population.
Hepatitis vaccines have been tried and tested for a long time (for hepatitis A and B). They have made their way into TV commercials, warning travelers to get vaccinated before they embark on exotic trips. It is true that the ice cube in a tropical drink could be the source of hepatitis, but it is a fallacy to believe, that staying home means being safe from hepatitis A and B. The demographics are also different: it is not only adventurous adult travelers that can get infected with hepatitis. Children share the same risk. They don't even have to travel!
In October 2005, the Advisory Committee on Immunization Practices, an advisory panel to the United States Centers for Disease Control and Prevention, recommended that all children age 12 to 23 months should receive a hepatitis vaccination. The vaccination would protect the young population not only against endemic but also imported viruses. A common source of infection can be agricultural products. Vaccination reduced the incidence of infection by 80% between 1999 and 2003.
There is always the question, whether this is just one vaccination too many, but bearing in mind that hepatitis can be a killer, the answer is more obvious. Hepatitis A has devastating consequences when super-imposed on chronic hepatitis C. Hepatitis C has been on the rise in the U.S., and there is no vaccination available. In order to avoid more serious consequences it is very likely of benefit to vaccinate children early.
BMJ 2006; 332:715-718 (25 March)
Life Extension Through Calorie Restriction
Animal experiments in the past have pointed out that overfeeding resulted in less life expectancy of the animal. Experiments with primates showed that withholding food did not compromise the health and vitality. To the contrary: the chimp lived well and even lived longer. Experiments with rodents are still very much removed from the application to humans, and to get closer to the facts, new research has enlisted the help of humans. Participants were randomized to 1 of four groups in a study that went on for half a year. The first group received caloric restriction of 25% of baseline requirement. A second group had 12.5 % caloric restriction, group three 12.5% more exercise with a structured program. A fourth group consumed a very low-calorie diet of 890 kcal until 15% weight reduction, which was followed by a weight maintenance diet.
At 6 months, fasting insulin levels were significantly reduced from baseline in the intervention groups. Core body temperature was reduced in the group with calorie restriction and the group with calorie restriction with exercise.
These findings suggest that 2 biomarkers of longevity (fasting insulin level and body temperature) are decreased by prolonged calorie restriction in humans. The metabolic rate is lowered as a result. DNA damage was also researched, and in the intervention groups (calorie restricted diets) it was lower. The 6-month study suggests, that calorie restriction may not mean deprivation, but less "wear and tear" on the metabolism. Studies of longer duration are required to determine if calorie restriction has the capability to slow down aging in humans.
JAMA. 2006; 295:1539-1548
Blood Clots Related To Air Travel
Extended air travel and sitting in the narrow seat of a plane has been blamed for the risk of deep vein thromboses (DVT). The formation of a blood clot in the leg veins is not only an inconvenience that causes severe leg swelling. It cannot be ignored, as untreated it may progress to an embolism, a clot that travels in the blood stream to lung or brain. Pulmonary embolism can kill! The affected patient needs treatment with blood thinners to dissolve the clot.
Pamphlets in planes encourage the traveler to move legs, feet and toes to counteract a stagnant blood flow in the leg veins. It remains a good practice for any traveler to get up and move about on lengthy flights. Some individuals are more susceptible than others to develop blood clots. It has been known for a while that the use of oral contraceptives is associated with a risk of clotting.
Dutch researchers under the leadership of Dr. Frits Rosendaal of Leiden Medical Center in the Netherlands recently published some of their findings. They examined, whether sitting for extended periods in narrow spaces would be the main risk for the formation of DVT. The volunteers were 15 individuals with no known risk factors for DVT. The group also had 11 women, who were carrying the factor V gene (a known risk for blood clotting), 15 women who were taking oral contraceptives, and another group of 15 women who had the factor V Leiden and were taking oral contraceptives. The entire group was taken on an 8-hour flight aboard a chartered 757 jet. Blood samples were taken before, during and after the flight. Several weeks later the same people sat through a movie marathon at a cinema, where the seats had the same legroom as the plane. Blood work was done as with the previous setting on the plane. No one was allowed to drink alcohol, take aspirin or wear compression stockings during the experiments. The test persons were asked to remain seated as much as possible, both during the flight and at the movies.
Finally the group was monitored for 8 hours while they went about their normal day-to-day routines.
The results showed that 17% of the entire group had early signs of possible clotting in their blood after the flight. After the movie marathon only 3% showed the same signs. The rates dropped to 1% during normal everyday routines. As predictable, the group with the factor V gene who were also taking oral contraceptives was at the highest risk.
As a result of these findings, the researchers believe, that sitting is not the only risk for the development of blood clots. The combination of low cabin pressure and low oxygen levels in jet travel may increase the risk for DVT in susceptible individuals.
The Medical Post, March 28,2006, page 50
Peanut Traces Still Present After Brushing Teeth
Allergy season triggers a lot of questions in patients who have had allergic reactions in the past. The most feared ones are anaphylactic reactions or anaphylactic shock from exposure to peanuts or ragweed. People with a history of allergies all have the risk of more severe reactions that need rapid intervention as anaphylactic shock can be deadly. People can be sensitized to various foods (peanuts, nuts, fish, shell fish, soy, wheat). Food additives often associated with allergic reactions can be sulfites (present in dried fruit and wine), food coloring (tartrazine) and flavor enhancers like monosodium glutamate. Beside those allergies, reactions to animal fur and dander, feathers, pollen of trees, grasses and weeds (ragweed being one of the worst) can be a challenge to allergy sufferers. People can get sensitized in any age group. Even adults who showed no allergic reactions in the past can come down with allergies later in life.
Education of the person with allergies is of great importance. Effective treatment does not only involve taking an antihistamine against allergies, which can be bought over-the counter. To get optimal control of allergy symptoms, evaluation with the help of an allergist is necessary, and skin tests will give more information. A regimen of allergy shots is an effective way to control allergies. It is also up to the allergic person to avoid substances that can be the cause of the problem.
Patients with food-related allergies should be aware that an injection with adrenaline (epinephrine) could make a difference between life and death in severe allergic reactions. Carrying an EpiPen (an injectable dose of epinephrine) is one important way of having an "emergency break". But carrying the device at all times is not enough. The user has to be fully knowledgeable as to how to use it and when to use it. Getting a prescription from the physician and proper explanation from physician as well as the pharmacist is the next important step.
Food allergies have received more attention over the past years. Food labels will show, whether a product may contain traces of nuts or peanuts, and many schools have banned the use peanuts among their students. It may sound like a radical approach, but given the fact that peanuts have shown disastrous reactions in allergic individuals, it is not a surprise. A new Ontario law, which was passed in 2005, is geared to make schools safer for children with allergies. After 13-year-old Sabrina Shannon from Pembroke, Ontario died at school in 2003 following food-allergy related anaphylaxis, the law requires every school board to establish and maintain an anaphylaxis policy. School staff must be trained in dealing with life-threatening allergies and emergency procedures must be in place.
Studies by researchers at the Mount Sinai Medical Center in New York showed that levels of Ara h 1, the major peanut allergen has staying power. Volunteers who ate a peanut butter sandwich had the allergen in their saliva for several hours after the meal. Clearance took up to 4.5 hours. The researchers went on to assess several interventions: vigorous tooth brushing for two minutes, tooth brushing and rinsing the mouth twice with water, rinsing the mouth without tooth brushing, and chewing gum for 30 minutes. All those intervention reduced the amount of peanut allergen, but none uniformly removed it! For persons with food allergies it is a warning signal: even a kiss from a person who recently ate the food (peanuts in this case) can cause dangerous allergic reactions. The presence of allergens in the saliva may or may not be applicable to other foods besides peanuts. More studies are needed, said Dr. Jennifer Maloney and her colleagues.
The Medical Post, April 4,2006, page 19-21
