The Travel Independently Blog

Influenzas:  Avian Flu, H1N1 (Swine flu) and other upper respiratory viral illnesses

Almost annually, there is a warning about a new flu strain that could impact on travelers. Often people forget that the seasonal influenza kills tens of thousands of people each year in North America.  So every year it is wise to get an influenza vaccine.

The vaccine used changes yearly based on the changes in the virus at the end of the previous flu season.  There are typically two attenuated (i.e.,dead) influenza viruses that are used in each vaccine.  The vaccine is an educated guess about the nature of the upcoming flu season.

Viruses mutate rapidly, so the vaccine effective for one year isn’t for the next.  And the flu viruses that infect people often trade genetic material with avian flu viruses and swine flu viruses.  Sometimes the mutations make the flu more serious either because so few people have any immunity so it sweeps through the population or because it is more severe and produces more serious secondary infections, such as pneumonia.

Contagion and prevention: Getting an annual flu vaccine can reduce your chances of catching the seasonal flu.  Influenzas are spread through person-to-person contact, most often via airborne droplets or touch.  While coughing and sneezing get the most attention, the virus is easily spread via the hands.  Thus, careful and frequent hand washing is an important preventive measure.  Be careful not to touch your eyes, nose or mouth, as all can be an entry point for viruses on your hands.  Remember that touching surfaces touched by someone who is ill is a direct transmission route.  Carry antiseptic hand wipes with you, but take time to wash your hands with soap and water frequently, especially before eating.

Airplanes, due to the dryness of the air and the fact that the air is re-circulated can make an airplane a prime environment for the transmission of viral illnesses.  There is little evidence that facemasks protect from airborne viruses.  However, if one has a cold or influenza, a facemask can help protect others.

So what can you do on an airplane to minimize your risk of contracting influenza?  Take along antiseptic hand wipes.   You may wish to clean the armrests, tray table and other surfaces by your seat.  Do use the hand wipes to clean your own hands especially before eating.  Stay well-hydrated.

So what about the avian flu, H1N1 (swine flu), etc?  What makes them different?  Why is the media inciting so much panic about them?

Influenza viruses vary in many ways, some are easy to transmit from one person to another, and some are very difficult to transmit.  Some are quite virulent, causing more severe symptoms and more severe complications.  So, for instance, the Avian flu is quite difficult to transmit person to person, the vast majority of cases have been transmitted via direct contact with sick or dead birds or their droppings.

But Avian flu is quite virulent, and most of the people we know of who contracted it died.  There may be more who lived, but the cases may not have been reported.  The Avian flu has been mostly confined to areas of southern China and parts of Vietnam.  There have not recently been reported cases of the Avian flu, but since we know that the virus is still active in various bird populations, it is expected that it or a variation of it will return.

The latest flu to worry people is a strain that was first detected in Mexico where it caused a number of deaths.  It was initially titled “swine flu” as it carries some genes from swine flu viruses, some avian flu genes and some human flu genes.  This flu has been of concern because it appears to be easily passed from person to person and there have been deaths among the young and healthy.

Seasonal influenzas, while causing deaths, mostly cause deaths among the elderly, infants and those who are already ill or have weakened immune systems.  Influenza that kills young and healthy people has the potential to cause pandemics.

The pandemic cited as the type that public health officials worry about is the 1917-18 influenza.  Millions died.  Indeed, more people died of the flu than died in combat in World War I, which was raging at the time.  This flu killed the young and healthy, and at times it killed within hours of the person falling ill.  Some researchers believe that the rapid deaths among the young and healthy were caused by an overwhelming response by the immune system that then caused collapse of the person’s immune system.  Usually flu deaths are related to complications such as pneumonia.

At present, it appears that the H1N1 flu is quite contagious but it does not appear to be very virulent.  So the Center for Disease Control and World Health Organization are both keeping a close eye on the spread of the virus and any changes in virulence.

The CDC website is an excellent source of information about the influenza outbreak.  It is updated frequently and it has links to the WHO pages on the outbreak.

Technorati Tags: H1N1 flu, Independent Travel, influenza, swine flu, travelers health

Many of the recommended immunizations for travel are immunizations one should have just to stay at home. These were covered in the last article. There are others, however, that are important for visitors to particular parts of the world.

Do your research first at the CDC website so you will be prepared to ask good questions when you see your travel medicine professional. Below are a few of the more common immunizations recommended or required for particular destinations.

Typhoid

Typhoid is a risk primarily in tropical countries. It is a disease of sanitation. In some parts of the world, there is antibiotic-resistant typhoid, making the vaccine more important for travelers. The vaccine has a lower effectiveness rate than most other vaccines, about 80-85%, but the risks make it a worthwhile vaccine for most travelers to tropical climes. The vaccine comes in two forms, an injection which is effective for 2 years and an oral vaccine, effective for 5 years.

Yellow Fever

Yellow Fever is currently the only disease for which a vaccination is required for entry into some countries. Countries where Yellow Fever is endemic, all of which are located in South America and Africa, require the vaccine for all travelers entering the country.

Yellow Fever is spread by mosquitoes, so using a good repellant is a wise precaution as well. Many countries require travelers who have been in a Yellow Fever endemic area during the last month to show evidence of having received the Yellow Fever Vaccine. You must have the YF vaccine administered at a certified Yellow Fever Center, and must have the formal documentation of the vaccine. The CDC website lists certified Yellow Fever Vaccine Centers.

Japanese Encephalitis

Japanese Encephalitis is yet another disease spread by mosquitoes. The animal vectors are ducks and pigs, so it primarily a disease of rural farming areas. It occurs seasonally in more northern areas of Asia such as northern China and Korea, but has an extended seasonal risk in the tropical areas of Asia. Most travelers are not at risk for JE. The CDC recommends the vaccine only for those people who will be spending extended periods of time in rural farming areas, at least 4 to 6 weeks.

Rabies

The rabies vaccine is different from other vaccines in that it does not prevent the development of rabies, but rather gives the person exposed to rabies a longer period of time to seek treatment. It also makes the treatment of the exposed person easier. Rabies is essentially 100% fatal once symptoms develop.

There have been only two documented cases of persons who developed rabies and have survived with intensive care. Rabies is transmitted through the saliva of infected animals, often, dogs, bats and monkeys, but any mammal can spread rabies. While animal bites are the most common route of transmission, rabies can be transmitted by an animal licking a person who has a skin break as minor as a scratch.

More on Rabies

Factors to consider in whether or not to have the pre-exposure vaccine include the incidence of rabies in the areas you are visiting, how far you will be from good medical care, and the activities you will be engaged in.

Those travelers who are at greatest risk of exposure, such as those who will have close contact with animals, those who are bicycling or hiking in areas with high incidence of rabies should consider the vaccine. The cdc website has a list of countries with high endemic rates of rabies. Note that India has the highest rate of human rabies in the world.

Pre-exposure vaccine consists of three shots of the rabies vaccine. If one is exposed to rabies and has had the pre-exposure vaccine, treatment consists of a series of two shots.

For anyone who experiences an animal bite, immediate first aid should be thorough washing with soap and water.

If one is exposed to rabies and has not had a previous vaccination, post-exposure treatment include a series of three shots plus human rabies immune globulin. In developing countries, the human rabies immune globulin may not be available, and Equine rabies immune globulin may be administered instead.

This serum has higher rates of serious adverse reactions than the human immune globulin, but given the seriousness of rabies exposure, it is still advised if no human immune globulin is available. In addition, post-exposure treatment for those previously not vaccinated is 5 shots of rabies vaccine.

This is the first article in a series on Travel Health

Some people are scared by the idea of traveling somewhere where immunizations are advised; others are oblivious, and don’t even read about recommended health precautions for the places they plan to visit.  You don’t need to be scared – or oblivious.  You need to be informed.

Vaccines

When people read about health precautions for visiting other countries, they often forget that we all take health precautions at home.  There are routine vaccines given to both children and adults that have cut the rates of infectious disease dramatically.  DPT (diphtheria, pertussis, tetanus) has been the way most people in the US get their first tetanus immunization.

Tetanus is an organism that is ubiquitous in the soil around the world.  An often fatal and always agonizing disease, the fact that it is rarely encountered in the developed world is a testament to the power of immunization. Check with your doctor to see if you need a booster.

Childhood Diseases

Childhood diseases (measles, mumps, rubella and chicken pox) are rarely seen in the US now except for small pockets of unimmunized children. A recent rise in US parents opting not to have their children vaccinated has yielded mini-epidemics of a number of childhood illnesses, some with very serious consequences.  People often think of these as fairly benign illnesses, but in fact, they can have serious sequelae in children including brain damage from very high fevers, and there are some deaths from these illnesses.

In adults, these illnesses are much more serious, with a greater risk of serious complications or even death.  These illnesses are encountered in places where these inoculations are not common, so as a traveler, you might have contact with them in any third world country and in other countries where children are not routinely inoculated.

If you did not have these illnesses as a child (which is believed to confer life-long immunity) or if you had the inoculations as a child but have not as an adult, check with your doctor about the advisability of a booster shot.

Polio

Polio, which has been nearly eradicated, does still exist in India and parts of Africa.  Periodically, there are reports of cases elsewhere, typically from an infected traveler.  If you have not had a polio inoculation as an adult, check with your doctor to determine if you are still protected.

Hepatitis A

Few people pause to think about what inoculations they would be wise to have to visit say France or Canada or Brussels or London.  But Hepatitis A is a vaccine it would be wise to have even if you are staying at home.  As with many other diseases, Hepatitis A is a disease of sanitation breakdown.   There are outbreaks of Hepatitis A in the US, Canada and Western Europe from time to time.   Two shots six months apart confer at least 20 years of immunity.  Some health care professionals believe we may find that the two shots confer life-long immunity.

Hepatitis B

Hepatitis B is a blood-borne illness.  It is spread by contact with blood and other bodily fluids.  Contact with blood via injury, unsterilized needles or medical equipment, blood transfusions with infected blood, or sexual contact with someone who carries Hepatitis B are all routes to contracting this serious illness.

There is a vaccine for Hepatitis B, often given in combination with the Hepatitis A vaccine.  It takes a series of three shots over an 18-month period to confer full immunity.  Many day care centers in the US require children in their care to be immunized, as children may have inadvertent contact with the blood of other children in a day care environment.

Travel Medicine Resources

There are a number of good travel medicine websites.  In the US, the standard of care is the Center for Disease Control website:  wwwn.cdc.gov/travel

While the information in this article can be helpful in thinking about immunizations prior to travel, it is no substitute for a visit with a travel medicine professional.

Next in this series:  Immunizations for travelers

Technorati Tags: diphtheria, hepatitis B, Independent Travel, tetanus, Travel Health, travel immunizations, travel medicine