Madely Health Headlines Commentary for April 9, 2010

Source:

B.C. measles outbreak expands to 26 cases

Related articles:

1. CMAJ issues warning over polio outbreak
2. Tanning beds do not reduce risk of sunburn but increase risk of melanoma skin cancers
3. Why the H1N1 vaccine program is focusing on high-risk groups first

Originally published in The Ottawa Citizen May 11, 2005
Original Title: Forget the Palms, Look at the Nails!

Many diseases can alter the appearance of our fingernails and toenails. Curvature changes, discolourations, lines and pits are clues used to diagnose various conditions.

Nails are made of stacked sheets or layers of protein called keratin. The soft whitish halfmoon area found at the base of the nail is called the lunula. The nail grows from a nail bed or matrix located just under the cuticle adjacent to the lunula. This matrix has two sections: The section closest to the cuticle’s edge (distal matrix) produces the deeper layers, and the section farthest away from the edge (proximal matrix) produce the superficial or top layer of the nail.

Changes in the colour of the lunula can be revealing. In patients with Wilson’s disease, a liver defect that leads to copper overload, the lunula can turn a blue hue (azure lunula). A red lunula can indicate heart failure, and the antibiotic tetracycline, commonly used to treat acne, can turn it yellow. Too much fluoride can turn nails brown or black.

Nails grow about one millimetre every six to 10 days. If the distance between the line and the nail bed is known, it can help the physician estimate when an acute disease began. Various lines running the length or breadth of the nail can appear at times. They can be the result of a bad flu, trauma, cold exposure or more severe disease.

A common benign condition in children and active adults is leukonychia. These are random uneven white lines that can appear on more than one nail. These lines do not span the nail. Minor trauma to the proximal nail bed is thought to be the likely cause and it is of no clinical significance.

Red or brown lines running the length of the nail can be splinter hemorrhages. These occur when the tiny blood vessels (capillaries) in the skin under the nail leak blood. This condition is a classic sign in people with inflammation of the inner lining of the heart (endocarditis). It is also seen in people who have lupus, rheumatoid arthritis, malignancies, trauma, psoriasis, localized fungal infection or peptic ulcer disease, and in women who are pregnant or using the birth control pill.

Yellow-nail syndrome occurs when the nail’s growth slows and it becomes thicker. The edges of the nail curve downward. The lunula disappears and the nail turns yellowish in colour.

People who suffer from chronic lung congestion (bronchiectasis), sinusitis, fluid accumulation around the outside of the lung (pleural effusions), immune system damage or deficiency, poor drainage of fluid away from the extremities (impaired lymphatic drainage) or malignant cancers can develop yellow-nail syndrome. Protein leaking from damaged nail bed capillaries is thought to cause the discolouration.

Ten per cent to 50 per cent of people with psoriasis will develop pitting nails. Psoriasis, allergic reactions or chemical irritation around the nail bed can damage the proximal matrix, causing small pits to form on the nail surface. Connective tissue diseases, pemphigus (a blistering skin disease) and alopecia areata (localized scalp hair loss) are other causes.

Clubbing, although technically not a nail change, occurs when the skin surrounding the cuticle can become thickened and spongy. It is associated with lung diseases like cancer, bronchiectasis, scarring (pulmonary fibrosis), cystic fibrosis and lung abscesses and celiac disease, cirrhosis, inflammatory bowel disease, and in some instances congenital heart disease and endocarditis.

When clubbing is noted without any other symptoms, a thorough investigation for lung cancer is required.

When the nail curves upward and away from the fingertip appearing spoon-shaped (koilonychia), it can be a normal variant in infants that resolves with several years. For older children and adults it can be a sign of iron deficiency, iron overload (hemochromatosis), or due to trauma or constant occupational exposure to petroleum-based solvents.

Unlike palm lines, your nail’s appearance can reveal more about you than you think. Ask your doctor to check them out.

Related articles:

1. Psoriasis: a lifelong torment often overlooked
2. Get a check up, but don’t check everything
3. Skin pigment changes have many causes

Originally published in The Ottawa Citizen January 23, 2005

Mad cow disease (bovine spongiform encephalopathy, or BSE) remains in the news, with two more cases reported in cattle this month in Alberta.

What is the incidence of this disease in Canada? How does it spread and what is your risk of contracting the disease if you eat beef? What is its relationship to Creutzfeldt-Jakob disease (CJD)?

Should consumers stop eating beef?

CJD is a fatal infectious disease that literally creates holes or gaps in brain tissue. The causative agent is the prion (proteinaceous infectious agent). Prions are normally found in small quantities on the surface of many cells, including nerve cells. A distorted form of this protein is responsible for CJD.

There are two forms of CJD: classical and variant.

Classical CJD is not linked to eating beef. It is a human disease occurring in older individuals (mean age of 65 years) whose incidence is about one per million people per year. People die about five months after disease onset.

Variant CJD (vCJD) appears in younger individuals. Indeed, a study out of the United Kingdom reported a mean age of onset of 29 years. People succumb about 14 months after diagnosis. It frequently causes psychiatric disturbances, cognitive impairment, involuntary body movements, immobility, unresponsiveness and mutism, among other nervous system damage.

In the United Kingdom, several factors contributed to the development of vCJD in humans: The cattle that people ate were exposed to the infection from the offal or feed that contained bovine brain and nervous-system ruminants, and slaughter practices contaminated the meat with the BSE prion. Fifty thousand infected cattle entered the human food chain. Despite this number of cattle, human infection rates were low.

There have been 155 reported cases of vCJD worldwide as of January 2004, including 145 from the U.K., six from France, and one each from Ireland, Italy, Canada and the United States.

Why, despite the level of contamination in some countries, has the number of worldwide cases remained small? Some of the proposed possible explanations include:

• A low level of the prion in milk and meat.
• The prion has difficulty causing infection when ingested orally.
• The cattle prion is not efficiently designed to spread to other species; there is a species barrier.
• There is a low incidence of certain genetic factors in humans that can increase the susceptibility to vCJD.

The single case of vCJD in Canada was related to this person spending time living in the U.K. There has never been a documented case of vCJD from a Canadian source of beef.

The latest reports from Health Canada and the Canadian Food Inspection Agency (CFIA) is that there are three confirmed cases of BSE in cattle in Canada. So, how does this affect the chance of contracting vCJD?

Health risk assessment is a mix of fact and perception. Indeed, Dr. William Leiss, scientist at the University of Ottawa McLaughlin Centre for Population Health Risk Assessment, has produced a thoughtful essay on the assessment of BSE risk in Canada.
Dr. Leiss states that, to accurately calculate risk, one must include not only the probability of infection but the consequences of the infection to society.

In other words, the first report of one cow with BSE in Canada in 2003 was enough for the U.S. to close the border to our live cattle and increase the public’s concern about infection (even though the documented individual health risk is negligible).

As Dr. Leiss writes, “BSE risk, however, is a classic case of the type known as ‘low-probability, high-consequence’ risk — others of this type are, for example, nuclear power plant accidents, severe earthquakes in populated areas, and terrorism events. In all cases of this type, the final risk estimation is driven overwhelmingly by consequences rather than frequency or likelihood (probability).”

Indeed, there have been health problems due to the impact of BSE: Farmers and people whose livelihoods depend on the beef industry have suffered from depression and other stress-related disorders. This in turn can introduce family stresses, damage relationships, and worsen existing health disorders.

There have been various classifications of risk. Sir Kenneth Calman, the chief medical officer of health in Great Britain, classified events into these categories:

• Moderate: Less than one in 100 but greater than one in 1,000 (smoking 10 cigarettes a day, parachuting, for example).
• Low: Less than one in 1,000 but greater than one in 10,000 (influenza, highway accidents).
• Very Low: Less than one in 10,000 but greater than one in 100,000 (leukemia, playing soccer, accident at work, murder).
• Minimal: Less than one in 100,000 but greater than one in 1,000,000 (railway accidents, horseback riding, fishing).
• Negligible: Less than one in 1,000,000 (hit by lightning or radiation leak from nuclear power station).

From an individual BSE infection-rate perspective, our risk is negligible. But from a societal health and economic perspective, the consequences of the disease have been, in Dr. Leiss’ calculation, “catastrophic.”

In short, it’s all about how you look at it.

Dr. Leiss’s report -  http://www.leiss.ca/bse/155
Health Canada – http://www.hc-sc.gc.ca/english/diseases/bse/

Related articles:

1. Waiting Your Turn: Hospital Waiting Lists in Canada
2. Waiting Your Turn: Hospital Waiting Lists in Canada
3. E. coli vacine for cattle reduces risk to population

Originally published in The Ottawa Citizen January 09, 2005
Original Title: Toxic Soup

All the ingredients for a potential health calamity are present

The tsunami survivors face great health challenges. To date there have not been reports of epidemics of cholera or other infectious diseases. However, the massive aid pouring into the affected regions is designed to address the health risks that have the potential to cause further harm.

All the ingredients for a potential health calamity are present: a contaminated water supply, lack of sanitation infrastructures, overcrowding, malnutrition, and endemic infectious diseases.

Human waste and decaying corpses contribute to the massive contamination. In effect, some of the survivors are living amongst a biologic toxic soup containing myriad pathogenic micro-organisms.

It is the children who will suffer most. Their weakened state impairs their ability to resist disease. Many can live without food for a week or more, but survival time is measured in days without clean water; they will rapidly succumb to dehydration, especially within the hot tropical environment.

With weakened immune systems comes an increased incidence of diarrheal illnesses, pneumonia, urinary tract infections and skin infections, among others. The severity of the illness and the survival rate is usually proportional to the time it takes to diagnose and treat it.

Indeed, bacterial diseases such as typhoid (Salmonella typhii), cholera (Vibrio cholerae), and enterotoxigenic E. coli are a major cause of dehydration, and are endemic in developing countries in Asia and Africa. All these organisms are found in contaminated food and water. They will also pass from person to person. Lack of adequate shelter makes it impossible to isolate the sick from the uninfected population.

Although the manner in which they cause disease (pathogenesis) differs, the end result is similar: They will infect and damage the intestines (enteric disease).

The small intestine absorbs most of the nutrients from food while the large intestine absorbs about 99 per cent of all water that flows through it. Damage to these structures can lead to bleeding and reduced absorptive capacity causing massive diarrhea.

Children and the elderly do not have as great a fluid reserve as do younger adults. In many instances, they must receive intravenous fluid replacement to compensate for their losses from diarrhea. The availability of clean water to drink will not help them in this case because the large intestine has lost its ability to absorb it.

The supportive care to treat cholera and other enteric diseases requires many litres of intravenous fluid replacement per patient. Some may need between 10 and 20 litres during the course of disease. Given the thousands of people that will contract these diseases, the resources alone for this one condition can strain available medical resources and supplies.

Contaminated pools of water attract disease-carrying flies, malaria and dengue fever-laden mosquitoes, and also harbour hepatitis A.

Without adequate shelter and netting for nighttime protection, the survivors are at risk for malaria and dengue fever. Left untreated, many will die. Waterborne parasites can also cause intestinal infection leading to cramps, bleeding and diarrhea. Most healthy people will recover from hepatitis A without any major consequences. However, the survivors of the tsunami have a greater risk of complications because of their weakened state.

Tuberculosis, a disease that affects two billion people worldwide — roughly one-third of the world’s population, most in developing countries — will claim more victims. This highly contagious person-to-person disease will have the opportunity to infect many others because of the living conditions and migration of people to temporary shelters or camps.

Some will have physical injuries that require proper wound care. Without treatment, these wounds will fester and infections will develop. Cellulitis is a common and potentially serious skin infection that normally starts in areas where there is pre-existing skin damage. The skin becomes swollen, red and hot and has a poorly defined border. The area of redness (erythema) rapidly expands and creeps along the skin within hours.

If diagnosed early, treatment consists of an oral antibiotic. Intravenous antibiotics are used if oral treatment fails or if there is an initial extensive spread of the infection. However, many of the survivors will not have access to prompt medical treatment. The end result is that a readily treatable infection will spread and increase the risk of septic shock and death.

The relief efforts are designed to counter the problems outlined, here. Setting up proper sewage and waste management systems will take time. Burying the dead, decontaminating water supplies, providing food and shelter and tending to the sick and injured are the initial focus of the recovery program. This in turn will slowly introduce order into a chaotic situation, but it will take months or years to remedy.

© Dr. Barry Dworkin 2005

Related articles:

1. Fighting pests that bug your intestines
2. Have needle, will travel
3. The onus is on you to prevent illness when on vacation

Originally published in The Ottawa Citizen Friday, November 12, 2004
Original Title: Infection control for dummies

Infection control can be a complicated matter, especially for viruses that spread as easily as the flu. The flu can spread through direct hand-to-hand contact, via airborne droplets (fomites) after a sneeze, and with contact with recently touched surfaces such as doorknobs, telephones, countertops and desks.

Preventing infection does depend upon “boosting your immune system,” but not in the way some believe it to be.

Our immune system begins at birth as a bunch of raw army recruits. They are healthy and strong but lack experience at recognizing and fighting the enemy. With training and combat they gain experience and become more efficient in their role as a standing army. Some are selected for special-forces duty and reconnaissance missions. They are able to track down and identify their target so that the army can move in and destroy it.

Our immune system follows this analogy. It has the potential to respond to threats from viruses and bacteria. Indeed, it will respond well to minor threats such as colds and minor cuts and scratches. But other pathogens, like the measles virus, polio, diphtheria, meningitis, typhoid and hepatitis, among others, can overwhelm the immune system. It tries to fight back, sometimes succeeding but with great collateral damage to organs and other structures.

If the system is trained to recognize these pathogens before the war, it stands a greater chance of protecting the body. This is the underlying reason why vaccines work.

Vaccines stimulate the immune system to develop antibodies, the body’s special forces that will seek out, identify and target the invader for the main battle group. Without these specific antibodies, the immune system is not co-ordinated to quickly prevent the attack and damage; you either lose the battle, suffer collateral damage or play a game of attrition — a draining experience.

Some argue that exposure to the pathogen is the preferred route of developing immunity, as opposed to using a vaccine. Indeed, the infected person will create antibodies and immunity if they survive the real infection. But this may come at a cost of permanent damage.

The vaccines contain either killed or weakened strains of the organism that have orders of magnitude less potential to cause harm compared to the original virus or bacterium.

Indeed, some will disagree with me and cite Internet references or studies that indicate the opposite. The response is that the studies to support vaccine use far outnumber the ones that imply the opposite. There is no conspiracy.

The flu vaccine is a “best assumptions” vaccine. It is predicated on what flu virus strains we expect will come into Canada and the United States from other regions of the world. If the assumption proves incorrect or incomplete, the importance of proper hygiene practices becomes more apparent.

What other infection control measures can people take for the upcoming flu season?

If you have the flu, isolate yourself from others and do not go to school or work. Wearing a properly fitted surgical mask and goggles with side protectors will help prevent catching the virus from an infected person or transmitting it to a caregiver.

Ineffective hand washing after sneezing into a tissue or coughing into the hand will leave viral/bacterial organisms on the hands. The perfect cleanser does not exist. However, a combination of products will offer substantial protection.

Soaps are excellent detergents and remove grit, grime, dirt, soil, and other organic compounds. The non-antimicrobial soaps fail to remove resident disease-causing bacteria from the skin but do remove some transient bacteria. Sharing a plain soap bar has the potential to spread disease because it can become contaminated.

Numerous studies indicate that alcohol (ethanol) washes dramatically reduce hand bacteria and viral counts after washing for 30 seconds. The alcohol gels should be used for at least 20 to 30 seconds and cover the entire hand and under the nails. Apply about a nickel- to quarter-size blob in the palm. If the hands dry in less than 15 seconds, insufficient gel was used.

There is an antiviral flu medication available called Tamiflu. It must be used close to the onset of the flu and will only reduce, not eradicate the symptoms and duration of the illness.

Carry a small squeeze bottle of alcohol gel with you and use it routinely to prevent the usual winter colds and flu this season.

Related articles:

1. The science of hand washing
2. Childhood rashes hard to diagnose at first
3. Microbiology 101: Why antibiotics don’t kill viruses

Originally published in The Ottawa Citizen October 18, 2004
Original Title: The HN factor

New information and reports of bird flu have shifted attention to the possibility of a new flu pandemic. The most lethal pandemic in our history occurred from 1917 to 1919 killing an estimated 20 million to 50 million people.

The World Health Organization (WHO) released a statement this month encouraging governments and pharmaceutical companies to begin production of bird flu vaccines.

To date there has not been any documented human-to-human transmission of the bird flu virus, but it is the high mortality rate for those who have caught it that has garnered attention. Millions of chickens have been killed during the past few years to contain the latest incarnation of the bird flu.

Why does the flu pose such potential danger, what are its origins and why does the vaccine change every year?

Imagine a beach ball with a small stick trapped inside it. Covering much of the beach ball’s surface is gritty sand. This is what influenza looks like under an electron microscope. The stick is the genetic material that infects us. The beach ball is the shell that protects the genetic material until it can invade our cells. The grains of sand represent the pieces of protein called antigens protruding out on the shell surface.

The antigens are designated with the “H” (hemagglutinin) and “N” (neuraminidase) monikers. For example, the bird flu has a designation of H5N1.

If our immune system is sufficiently primed for this viral invasion it will attack the antigens on the shell. The shell will break open and the immune system’s cells move in to destroy the genetic material before it causes disease. Our bodies develop immunity with each exposure to the flu virus and with each vaccination.

Many viruses slowly mutate or change over time. Most healthy people can adapt to these minor changes.

Epidemics and pandemics occur when the virus (usually Influenza A) undergoes a radical genetic change over a short time. This occurs when a human and bird virus both infect an animal simultaneously. The viruses swap genetic material, forming a new strain.

Because the immune system has never seen this new strain, it has no counter-measures to fight it; the body is defenceless.

Scientist Yoshihiro Kawaoka, of the University of Wisconsin-Madison and the University of Tokyo, looked into why the Spanish flu was so lethal. He stated, “We found that just one gene called HA, hemagglutinin, is sufficient to make a benign virus pathogenic.” The results of the study were reported in the journal Nature.

“One of the hallmarks of the 1918 Spanish flu is hemorrhage in the lungs,” said Mr. Kawaoka.

The suspicion is that the Spanish flu originated from birds. The research team wanted to look for clues within the genetic code of the virus that could help predict future lethal strains before they had a chance to spread.

Those most vulnerable are people over age 65, pregnant women, young children and those with chronic illnesses like asthma diabetes. Hospitalization rates for children under the age of two who have the flu are equal to those over 65.

The historical record of flu pandemics, the last in 1968, indicates a cycle of roughly 20 to 30 years; we are overdue. The WHO’s concern is that the world is unprotected against the bird flu virus, hence its recommendation for vaccine development.

The vaccine’s ability to protect you is determined by how closely they can match the strains that will arrive in North America each year. With a close match, protection rates against clinical influenza approach 70 to 90 per cent.

The flu vaccine contains dead viruses; it does not cause the flu. The vaccines cause side effects less than five per cent of the time. These commonly include a low-grade fever and fatigue for eight to 24 hours after immunization; minimal discomfort compared to the actual flu.

The vaccine is recommended for:

• Persons 65 years of age or older;
• Residents of nursing homes and chronic care facilities that house people with chronic medical conditions;
• Adults and children who have chronic heart and lung disorders, including children with asthma;
• Adults and children who with chronic diseases including diabetes mellitus, kidney failure, anemia or poor immune system function;
• Healthy pregnant women in their second or third trimester;
• And you!

Ottawa Public Health does not recommend the vaccine for people with:

• A previous allergic reaction to influenza vaccine;
• An allergy to eggs or thimerisol;
• A changing neurological condition;
• A history of Guillain-Barre Syndrome;
• A history of Oculo-Respiratory Syndrome.

Studies in the United States demonstrate marked cost savings to the health care system and increased work productivity. In one study, vaccinating working adults reduced absenteeism by 50 per cent.

Related articles:

1. There’s no good reason to avoid taking a flu shot
2. Chickenpox Vaccine is Effective
3. New flu vaccine production process

Originally published in The Ottawa Citizen September 7, 2004

Original Title: The heebee jeebee itch

With the beginning of the school year, cold viruses, potential allergens and other infections are ready to greet our children at the door.Although we handle these situations well, the anxiety meter reaches a crescendo when we face those nefarious villains: scabies and head lice (Pediculosis).

Mention that your child has head lice and watch your friends and family members slowly back away from you, start scratching their heads or bodies and run for the nearest door.

What can parents and schools do to prevent and treat these infestations? Where do they come from and how do infestations occur?

Let us enter heebie-jeebie territory.

Head lice (Pediculus humanus capitis) are one of three types of lice that live only on humans. The other two are pubic lice (Phthirus pubis or crabs) and body lice (Pediculus humanus corpus). Contrary to popular belief, these insects do not fly, jump or hop from person-to-person, nor are they related to poor hygiene and low socioeconomic status.

Head-to-head contact is the primary mode of transmission, although sharing hats, combs and brushes can do so as well. Three- to 11-year-old children are most susceptible, especially girls because of their social behaviour.

The infestation can start two or more weeks prior to the development of the allergic reaction and itch (due to the louse’s saliva). Children will frequently scratch their heads once the bugs have set up shop.

Detecting lice can prove difficult because they move rapidly. Indeed, many will see the lice eggs or nits — tiny oval-shaped blobs that stick out at an angle from the hair shaft. Nits can be confused with normal skin flakes or dandruff. Dandruff is brushed off the hair shaft whereas nits are glued in place.

Finding nits does not mean there is an active infestation. If microscopic examination of the nit shows it contains an embryo or you find at least one louse, then there is an active colony. All family members must be examined for lice under this circumstance.

Eradication of head lice includes a combination of mechanical removal of nits with a nit comb or brush, substances to asphyxiate them, certain antibiotics and/or an insecticide. The insecticides are toxic to the louse’s nervous system.

Solvents such as formic acid and white vinegar will dissolve the cement that holds the eggs on the hair shaft, enabling easier removal of the nits. Although it may create a bit of a mess, applying olive oil and wearing a shower cap for six hours per day for four consecutive days may kill the lice and nits. Using petrolatum (Vaseline) on eyelashes produces good results.

The treatment of choice is usually an insecticide such as permethrin (Nix or Rid shampoo). It is safe and effective, it can be used even by those who are pregnant. Suspect insecticide resistance if lice are found alive 24 to 48 hours after treatment. Your doctor will recommend another agent.

Given that lice survive for only a day if separated from the human host, a simple wash of recently worn clothes is all that is required. Vacuum the furniture, toys and other household objects. A complete scrub-down is unnecessary.

The scabies mite (Sarcoptes scabiei) shares some of the head louse’s characteristics: it is a human parasite and is transmitted by direct contact. However, it can survive up to four days away from its human host on clothing, bedding and upholstered furniture. Contact with any of these infested objects can result in the bug’s transmission.

It will burrow into the underarms, elbow creases, waist, groin, buttocks and feet to lay its eggs. These areas become intensely itchy from the louse’s excrement and a bumpy red rash can develop. Skin damage (excoriations) occurs from the intense scratching. Infants may demonstrate larger sores or bumps on their skin and have head and neck involvement.

Adults and children older than five years of age can use a five-per-cent solution of permethrin. After a bath or shower, the cream is applied from the neck down to cover the entire body surface. It is washed off after eight to 14 hours. One application has a cure rate of about 90 per cent. Although generally safe for use by pregnant women, breastfeeding should be delayed or halted until all residual cream is washed off the skin.

Treatment failures should be assessed by your doctor.

Itching and discomfort can continue for up to four weeks after treatment. Leftover pieces of the mites will remain buried under the skin until the skin regenerates and sloughs the debris away. Antihistamines can help treat the itch.

All clothes, linens, towels, and upholstered furniture used in the previous four days must be decontaminated or the cycle of infestation may recur.

More information can be found at HealthyOntario.com .

© Dr. Barry Dworkin 2004

Related articles:

1. The facts of lice life
2. Risk of recurrent head injuries in children
3. Childhood rashes hard to diagnose at first

Originally published in the Ottawa Citizen, July 19, 2004
Original Title: Preventing malaria when you travel

Hippocrates (460?-377 BC) described it in his written observations. Ancient Chinese, Egyptian and Middle Eastern cultures refer to this disease. Outbreaks often coincide with warfare, mass migrations and other societal disruptions.  The British blamed “bad air” in the mid 1800’s India for a disease that killed many of their nationals. This mala aria (from the Italian) has killed more soldiers in the 20^th century wars than bullets. The World health Organization reported 270 million worldwide cases and one million deaths in 1998.

Contrary to popular belief, malaria did exist in the Americas and arrived here as early as 1493. High risk areas for malaria include Central and South America, Haiti and the Dominican Republic, Southeast Asia, Africa, India, and the Middle East.

In 1638, Spanish Jesuit missionaries brought South American cinchona bark back to Europe. The bark, the first treatment for malaria contains quinine. Tonic water was used as means to make the drug more palatable.

Malaria spreads by the bite of an infected Anopheles mosquito. Once the parasite enters the blood stream it heads to the liver to reproduce. The red blood cells will carry the parasite that can infect more mosquitoes if you are bitten.

Over 80 percent of people with malaria will develop chills, sweats, headaches, fever, muscle aches and joint pain. Others in addition may experience a loss of appetite, nausea, vomiting and abdominal pain.

It can take ten to 28 days after the mosquito bite to develop symptoms. Indeed, malaria can appear in as little as eight days after a bite or one year later depending upon which of the four common types of malaria parasite is involved.

How can you assess your risk of contracting malaria?

Your doctor will need to know exactly where you will be traveling and your accommodations. This includes the specific cities or regions within the country. The destinations’ elevation is important because malaria transmission is rare 2,000 metres above sea level.

Many organizations monitor malaria. The country’s malaria risk can vary throughout the year and with the seasons. Some areas may be devoid of malaria while there may be pockets of severe infestation.

If you are a night owl and spend time outdoors, beware; the Anopheles mosquito feeds from dusk to dawn. Even as little as an hour of outdoor nighttime exposure can lead to infection.

People commonly wait too long before consulting their doctor for travel vaccines and malaria prevention. Certain vaccines and malaria medications must be given weeks to months before you travel so that they can provide maximum protection. Visit your doctor at least six weeks before your departure.

The choice of antimalarial medications will be linked to your destination and the latest information from travel medicine advisory centres. Although antimalarial drugs can significantly reduce the chance of infection, they are not foolproof. Furthermore, it is mandatory that the medications be taken exactly as prescribed. If not, it will provide an opportunity for the parasite to infect you even after you have returned home. Indeed, there are many endemic areas that have specific patterns of antimalarial drug resistance

Prudent malaria prevention actions include:

• Curtail nighttime activities. Wear long sleeve shirts and pants when outside at night.
• Insect repellents like DEET in concentrations of approximately 30 percent for adults and ten percent for children should be used on the hands and face and other exposed skin. Spray it on clothes as well. Reapply every three to four hours.
• Check your accommodations to make sure they have screens over their doors and windows or make sure they are shut tight at night. If possible choose a room that is air-conditioned since the mosquito likes heat.
• Drape the bed with mosquito netting permeated with the insect repellent permethrin. It can reduce the mosquito attack rate by 97 percent
• Stick to your medication schedule and complete the course even after you return home.

Consult your doctor immediately if you develop a fever after returning home.

For more information visit these sites:

CDC Travelers’ Health Information: www.cdc.gov/travel
Malaria Foundation International: www.malaria.org
International Association for Medical Assistance to Travellers: www.iamat.org

Related articles:

1. A look at an experimental malaria vaccine
2. Malaria risk when traveling
3. Malaria prevention when traveling

Originally published in The Ottawa Citizen June 11, 2004

Original Title: Stay away from Puss ‘n Boots

We live with a multitude of bacteria and parasites in our environment. Many do not cause disease in healthy individuals.Toxoplasma gondii is a protozoan that is relatively harmless for most healthy people. Although pregnant women have the same risk of contracting the parasite as the general population, they should take precautions to reduce their risk of exposure to toxoplasma.

There are about 250 new cases of toxoplasmosis (toxoplasma infection) per year in Ontario.

Toxoplasmosis can cause harm to a developing fetus. About 10 infants will be infected per year in Ontario. Approximately 32 to 40 per cent of Canadian women are immune to toxoplasma due to previous exposure; they will be able to protect their unborn child. Indeed, mothers exposed to toxoplasma six months before pregnancy do not pass the infection on to their child.

Infected pregnant women will not have many symptoms. It is the fetus that is at risk. Toxoplasma will cross through the placenta to the fetus an average of 30 to 40 per cent of the time. The transfer risk, about 15 per cent, is lowest in the first trimester but it can cause severe nervous system disease, spontaneous abortions and stillbirths. By the third trimester the transmission rate is about 60 per cent but the fetal disease is mild.

About 70 to 90 per cent of infected newborns will not have any initial symptoms. Indeed, it may take years to develop. However, if left untreated 85 per cent will develop blindness or impaired vision due to chorioretinitis (inflammation of the retina and surround eye structures). Ten to 30 per cent will experience moderate hearing loss and 25 to 75 per cent will manifest some developmental delay and brain damage.

Some of the signs that do suggest toxoplasmosis at birth include fever, enlarged liver and spleen, small head size (microcephaly), jaundice, seizures and rash. An infant that has water accumulation in the brain (hydrocephalus), chorioretinitis and calcium deposits on the inside of the skull strongly suggest congenital toxoplamosis.

Prevention is paramount during pregnancy.

Many people focus on cats as the primary risk of toxoplasma infection. Once a cat is infected it will only spread toxoplasmosis for a few weeks thereafter. Kittens are more likely to spread the infection because they have not yet become immune to the disease.

Daily cat litter changes done by a healthy, non-pregnant individual will prevent the parasite’s eggs from becoming infectious spores. It takes four days to change from egg to spore. Keep your cat indoors to reduce your chances of catching toxoplasmosis. Feed it dry or canned cat food and not uncooked or undercooked meat scraps.

Despite the cat precautions, cats and cat litter are not the major source of infection.

Indeed, 25 per cent of fresh pork and lamb have cysts containing toxoplasma. Eating raw or partly cooked meat, handling it or touching the cutting board or dish that it was in contact with it, and then putting your hands to your mouth, can transfer the infection.

Since toxoplasma is found in the soil, be sure to wash all raw fruits and vegetables. Avoid unpasteurized goat’s milk or cheese.

Other prevention methods include:

* Wear gloves while gardening because cats often use gardens as litter boxes.

* Wash all cutting boards, dishes and other items with hot soapy water after they have been in contact with raw meat, poultry, seafood and raw fruits and vegetables.

* Cook meat until it is no longer pink. The meat thermometer should read 160 degreesF (71 degreesC). Do not taste meat until it is well-cooked.

* Avoid drinking the water when travelling to underdeveloped countries.

Toxoplasma is treatable but its success depends upon early diagnosis. Routine screening is not done in Canada because of the relatively low prevalence and the blood tests would not provide an accurate assessment of infection.

The bottom line is for pregnant women to reduce their exposure to sources of toxoplasma. If you suspect you are at risk of exposure to toxoplasma and are pregnant, please consult your physician.

© Dr. Barry Dworkin 2004

Related articles:

1. What is contributing to teen hearing loss?
2. Routine male circumcision could reduce a man’s risk of HIV infection
3. What foods and dietary patterns reduce the risk of heart disease?

Originally published in The Ottawa Citizen May 29, 2004
Original Title: Bugs down the gullet

They have exotic names but they are less than endearing. Intestinal parasites come in all shapes and sizes. Each has its own way of taking advantage of the body’s metabolism and anatomy.

Although there’s a wide variety of parasites, let’s look at the most common vermin to hitchhike the intestinal highway (sorry, if you are eating breakfast).

Pinworm or Enterobius vermicularis is a worldwide infection affecting about 200 million adults and approximately 30 per cent of children.

These small roundworms or nematodes measure eight to 13 millimetres for females and two to five millimetres for males. Transmission of the parasite’s eggs occurs via the fecal-oral route. Poor hand washing and hygiene can transfer them from person to person.

Once the eggs are swallowed, they hatch in the initial portion of the small intestine called the duodenum. From there they migrate to the large intestine and settle in the cecum located in the right lower quadrant of your abdomen. The female will take a nightly crawl from the cecum to the outside edge of the rectum where she will lay up to 15,000 eggs.

This infestation causes few symptoms, is self-limiting and lasts about six weeks (if the host person remains isolated from any new infected contacts).

Rectal, vaginal and perineal (the skin between the rectum and vagina or scrotum) irritation and itch are the most common symptoms. Indeed, children who complain of rectal itch and are unable to sleep may have pinworm. Weight loss, bladder infections and appendicitis are very rare complications.

Applying cellophane tape to the rectal area will pick up the eggs. They can be seen under the microscope.

One dose of mebendazole (Vermix) taken two weeks apart will kill the pinworms. Prevention includes treating household contacts and cleaning the bedrooms and beds.

Giardia lamblia often invades individuals who hike in the wilderness, hence its nickname “beaver fever.” Poor sanitation and contaminated waterways contribute to this protozoan’s worldwide presence. Like pinworm, it follows a fecal-oral route of transmission but lives in water.

Indeed this infection, known as zoonosis, can survive in chlorinated city water and cold mountain streams. It infects many species including beavers, dogs, rodents, cattle and bighorn sheep, thus ensuring a rich reservoir.

Giardia will incubate for about two weeks before symptoms occur. It may cause an upset stomach, nausea, fatigue, gas, cramps, fatty stools, weight loss and diarrhea. Some may have itching and rashes. The infection persists two to four weeks. Malaise, fatigue and depression may wax and wane over many months if the condition is not treated.

A stool examination for ova (eggs) and parasites will uncover giardia. Treatment with the antibiotic metronidazole will eradicate the infection in adults.

The infection can be prevented by employing proper sewage treatment and disposal. Travellers to at-risk areas should drink only bottled water. Water treatment options include boiling for one minute, using iodine water-purifying tablets eight hours prior to drinking, and proper handwashing technique.

Entameba histolytica is another protozoal infection spread by the fecal-oral route. Poor hygienic food preparation techniques and food grown in soil fertilized with human waste are common worldwide problems. Ten per cent of the world’s population carries the infection. Although 90 per cent of infected people do not have symptoms, the remaining 10 per cent or 50 million people will experience intestinal bleeding, fatigue, weight loss, severe abdominal cramps and pain, copious bloody diarrhea and fever — worldwide, 100,000 die each year from it.

It can escape from the intestine, causing abscesses in the liver and the tissues lining the lung (pleura) and heart (pericardium).

Metronidazole is a common antibiotic choice for uncomplicated infestation. Avoid eating unpeeled fruits and vegetables when travelling to endemic areas. Stick to bottled water and use iodine tablets for any non-bottled water source.

Consult your doctor should you experience diarrhea and malaise after travel.

Related articles:

1. Why Children will suffer the most
2. Fighting Back Against the “Silent Disease”
3. The onus is on you to prevent illness when on vacation