Malaria Vaccine

travelmedicine
by Dr. Rajiv Narula

Malaria

Among the many diseases transmitted by mosquitoes, malaria is one of the most dreaded, and yet pre­ventable, causes of mortality among travelers. The geographic distribution of malaria covers most tropical regions and some warm temperate regions of the world. Risk of malarial transmis­sion decreases above 4,500 feet, how­ever in hotter climates, it may occur at heights above 9,000 feet. Last summer there was a big outbreak in Kissi, Kenya - altitude 6,000 feet.

Malaria is transmitted by the bite of the female Anopheles mosquito that injects the malaria parasite into the blood. These usually bite between dusk and dawn. Early symptoms are flu, fever, chills, muscle aches, headaches and sometimes vomiting and diarrhea Severe cases can rapidly progress to mental confusion, liver and kidney failure, convulsions, coma and death.

Making an early diagnosis is cru­cial to a successful outcome. You may have any of these symptoms from one week to several months after possible exposure to the mosquito. The period between the bite and the onset of ill­ness is usually seven to 21 days but can be several months.

There are four species of malaria which can infect humans and cause ill­ness, however only Falciparum Malaria can be life threatening; it can be treat­ed effectively in its early stages. Yearly about 300-500 million people contact malaria, out of that 2-3 million will die! One million people die yearly in Africa alone, the second biggest killer on the continent after AIDS, according to the United Nations.

Travelers can protect themselves by avoiding mosquito bites by minimiz­ing outdoor activities at night, wearing proper clothing, taking the correct anti-malarial medications, using repel­lents such as DEET and permetherine and mosquito nets. You cannot reduce the risk to absolute zero, but using this three-layer strategy will reduce the odds significantly.

The choice of anti-malarials is of paramount importance, as picking the correct one depends on the patient’s medical history- allergies, health status and itinerary. Studies done in Canada and Europe have shown that only between 11-27% of travelers were given the correct recommendations for protection.. This shows the importance of getting these recommendations from a reliable source. Vaccines for preven­tion are being developed and will hopefully be available in a few years. Until then, try not to make yourselves feeding grounds for mosquitoes.

Motion Sickness

travelmedicine
by Dr. Rajiv Narula

Motion Sickness by Dr. Rajiv Narula

Motion sickness is a common problem encountered by travelers – whether by sea, air land, camel or elephant ! We all suffer from it, the difference lies in the level of discomfort- 5% suffer heavily, 5% suffer minimally and the remainder 90 % suffer moderately. According to the Medical College of Wisconsin from one third to one half of airline passengers experience some degree of motion sickness when encountering heavy turbulence.

The body has two pathways whereby it maintains balance, one is visually and the other is maintained by the inner ear. Both inputs are relayed to the brain. If the brain is sent conflicting messages, which is what occurs, when for example, one is below deck on a ship. Visually your eyes see very little motion, because one is unable to see the horizon , however the inner ear senses the motion. Both these in turn send the brain conflicting messages which results in symptoms of motion sickness.

Symptoms vary from person to person, these generally consist of malaise, cold sweating, abdominal discomfort, nausea and vomiting. Other symptoms may include drowsiness, salivation, hyperventilation, headache and flushing. There is also a major psychological component ; some persons develop some of these symptoms in anticipation of an air flight or a boat ride. Most people will adapt rapidly to motion, that is they will be able to tolerate the motion that made them sick at the beginning of their voyage. The French term for the debilitating effect of motion illness is Mal de Mar, luckily it is not life threatening, although the person suffering sure feels like they are in a bottomless pit. Women are usually more susceptible than men, this is worsened near menstruation and pregnancy. Factors that can predispose one to feel motion sickness include – alcohol, certain drugs, and as stated earlier, anxiety levels and sleep deprivation. An interesting study published in Aviation Space Environmental Medicine in 1993 showed that Chinese subjects were more susceptible than Caucasians.

There are many remedies that are used, ranging from use of behavior therapy – avoiding rooms without a view of the horizon, to eating ginger , to using wrist bands and also the use of prescription medications in oral as well as in transdermal forms. Yet others believe in avoidance of certain foods prior to and during the trip.

The first scientific study regarding the use of ginger was published in 1982. In this study 940 mg of ginger were shown to be more effective than Dramamine 100 mg. However other studies have shown it not to be effective in certain situations. Issues that remain to be looked at include the quality of the ginger preparation and the time that is required for it to produce it’s effect. The most common prescription medication is probably scopolamine, it comes in two forms an oral preparation and a transdermal format. The ‘transderm patch’ is applied behind one’s ear, 6-8 hours prior to departure. Medication is released in a fixed dosage, it penetrates the skin and is then absorbed. Absorbtion differs between different persons and unfortunately in some cases may be too much, the amount released differs from person to person. On the other hand the oral formulation can be taken an hour before travel, and is effective for 8 hours. The dose can be titrated to the person’s weight and individual needs. It would be advisable to try the oral preparation prior to the patch. Both these can have the side effect of causing some drowsiness, use of alcohol with them must be avoided. Alcohol is perhaps the last thing on a person’s mind when they have that dreaded feeling of mal de mar !

DVT

DVT
by Dr. Rajiv Narula

Do an Internet search on ‘Economy Class Syndrome’ and you are likely to come up with a long list of articles/ links. The death of a 28 year old woman, after a 20 hour flight from Australia to England, from a blood clot in her lungs ,has been a popular news item in Australia and the UK. The Australian government and a British Parliamentary committee are commissioning a study on Deep Vein Thrombosis or DVT and its relationship to air travel. The person who coined the term Economy Class Syndrome, perhaps spent a restless part of their trip in the dungeons of an airplane – the ‘economy’ section. This section usually has fares advertised in national newspapers and when you call, they are usually sold or not available due to one of those reasons listed at the bottom of the page.

Deep vein thrombosis usually presents as a warm, swollen, lower extremity. Risk factors include pregnancy, post operative after orthopedic and pelvic surgery, prolonged periods of immobility, having certain cancers, especially pancreatic cancer and women on oral contraceptive pills. Diagnosis can be made clinically, but is usually confirmed by an ultrasound study of the leg veins. Therapy consists of the use of blood thinners. These may need to be used for 6 months or longer, requiring frequent blood monitoring. A small percentage of these blood clots will travel to the heart and lung, where they may cause death. This is most likely the cause of death of that young woman who died when she reached the UK from Australia.

Air travel, especially when one is stuck in the back of the plane where leg space is minimal, could play a role in the formation of one of these deadly clots. Studies have shown that flights that are more than 8 hours in length can also play a role. People who try and pass time by drinking alcohol, are infact dehydrating themselves( alcohol inhibits the absorption of water), the one consolation in this is that they need to go to the bathroom on a regular basis, so they do do some stretching, unintentionally !

Possible strategies to reduce your chances of developing a blood clot from flying includemaking sure you are well hydrated before and during your flight, do some low level exercise/ stretching while in flight. Try to get an aisle seat so that you can get out without aggravating your fellow passengers. Research by Japanese researchers found that in an airplane environment , food and non alcoholic beverages improved oxygen levels in the body by 21% and by 48% in the brain. According to Dr. Makoto Matsumura, Assistant Professor of Cardiovascular Surgery at Saitama Medical School , Japan, “ after eating and drinking, blood volume may be increased.” This increase in blood volume, reduces the chances of clot formation in the veins of the lower legs.

Some airlines, like British Airways, Air New Zealand and some Australian airlines possibly sensing legal ramifications are giving passengers warning leaflets with their tickets. However, according to the news agency, Reuters, 800 Australians have signed up with a Melbourne law firm seeking damages from various airlines due to issues resulting from this.

Dengue Fever Vaccine

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travelmedicine
by Dr. Rajiv Narula
Dengue Fever - a Global Health Problem, Why You Should be Concerned

Dengue Fever is a mosquito- borne, viral illness occurring primarily in tropical and sub-tropical regions of the world. The risk is greatest in the Indian sub-continent, Southeast Asia, South China, most countries in Cen tral and South America, Mrica, the Pacific islands, and even Texas, where there were cases last year.

This shows that Dengue Fever is a widespread problem with up to 100 million cases worldwide in
one year. The increase in population and unplanned urbanization has led to sub standard housing, water and sewage treatment, and poor mosquito control. The increase in air travel has allowed the virus to move through the world.

The virus is transmitted by the Aedes Aegypti mosquito, which lays its larvae in artificial water containers, such as discarded tires, plastic containers, flower vases.

The illness is characterized by the sudden onset of high fever, severe headache, joint and muscle pains and a rash. The disease is usually benign and self-limiting, but convalescence may take weeks. Their are no known permanent effects of the disease.

Prevention and control of Dengue Fever are important as there is no known effective vaccine on the mar ket. Travelers can avoid getting the fever by using DEET on exposed skin, and Permetherine repellent on cloth ing and mosquito nets. Travelers should stay in airconditioned hotels with well-kept grounds.

If you feel you have caught Dengue Fever, avoid analgesics with aspirin; use those with acetaminophen, and get rest, drink plenty of fluids and see a doctor.