An outbreak of Ebola hemorrhagic fever in the west African nation of Guinea has revived fears of a global contagion, but infectious disease experts say Ebola poses little threat to travellers.
Although Ebola violently attacks the body and kills up to 90 per cent of those infected, it can only be transmitted via bodily fluids, which greatly reduces its ability to spread, says Jay Keystone, a travel physician and professor in the department of medicine at the University of Toronto.
"If we had a case in Canada we'd isolate the case, the patient would live or die, and we'd be highly unlikely to have it transmit," says Keystone.
In terms of transmission, he adds, "there are far worse diseases out there."
The biggest recorded outbreak of Ebola was in 2000 in Uganda, with 425 infected and 224 dying as a result, according to the World Health Organization (WHO). But large outbreaks like this have happened only about once per decade, and most years the WHO records a handful of cases or none at all.
In comparison, according to the WHO, malaria kills 1.2 million people annually, while 100,000 to 120,000 people die every year from cholera.
The Public Health Agency of Canada has posted a list of 32 of the most prominent diseases travellers need to be concerned about.
Mark Tyndall, head of the division of infectious diseases at the Ottawa Hospital, says that worried flyers should consult a travel physician to find out if there are specific health concerns and precautions for the regions they plan to visit.
"We have quite a good network in Canada of travel clinics, and if people are travelling, they should take advantage of these places where people know exactly what [travellers] should be concerned about for different countries," he says.
Here's a look at some of the most infectious diseases around the world.
Food- and water-borne diseases
Countries such as Mexico and Cuba are popular destinations for Canadian travellers, but visitors run the risk of contracting food- and water-borne illnesses due to bacteria such as E. Coli, which can contribute to so-called "traveller's diarrhea," as well as diseases such as hepatitis A, which in extreme cases can lead to liver damage.
According to the Public Health Agency of Canada, E. Coli and hepatitis A thrive in "locations with poor sanitation or unsafe food handling practices."
There are immunizations available for hepatitis A.
As for those nasty E. Coli bacteria, Tyndall says "we can't do much about that other than equip people with some antibiotics to take with them in case they get diarrhea."
Tyndall says typhoid fever, a bacterial disease transmitted through food or water contaminated with the feces of an infected person, remains a particular concern in many Asian countries. A typhoid infection typically lasts four weeks, and can include severe stomach pain, internal hemorrhaging and even fits of delirium.
A typhoid vaccine is available, although it is not 100 per cent protective, says Tyndall.
"Vector-borne" diseases — or diseases transmitted by insects and ticks — affect millions of people every year.
Malaria, the most deadly vector-borne disease, kills more than 1.2 million people annually — mostly African children under the age of five, according to WHO.
Insect-borne diseases such as malaria and dengue fever are typically found in subtropical countries and are transmitted by mosquitoes. Both diseases can produce headaches, joint pain and vomiting, but the latter can develop into dengue hemorrhagic fever, which can lead to significant blood loss.
There is no effective vaccine for either disease.
For many people, the most frightening diseases are those that are transmitted via the air. Spread by coughing and sneezing, measles is one of the most contagious viruses known to science.
Measles, which produces a fever and severe rashes, kills an estimated 122,000 children every year, according to the U.S.-based Measles & Rubella Initiative. Most North Americans are immunized as children against measles, but it remains a major concern in India and southern Africa.
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- Manitoba confirms 2nd measles case in Winnipeg
Tuberculosis, another airborne disease, killed 1.3 million people in 2012, according to WHO. It is a leading killer of people with HIV. TB is caused by bacteria that typically affect the lungs, leading to chronic cough, fever and weight loss. Travellers can be vaccinated for TB.
Diseases transmitted by bodily fluids or blood
Although Ebola gets a lot of media attention, the Lassa hemorrhagic fever is far more prevalent, says Jeffrey Lee, an assistant professor in the department of laboratory medicine and pathobiology at the University of Toronto.
The Lassa virus, which is endemic in west African countries such as Sierra Leone, Guinea and Nigeria, infects between a quarter to half a million people a year and kills nearly 10,000 people annually, Lee says.
"With Ebola, we have these [small] outbreaks, but the Lassa virus is definitely more of an emerging virus," he adds.
As with Ebola, there is no vaccine for Lassa.
Like Ebola, human immunodeficiency virus (HIV) is transmitted by bodily fluids — typically through unprotected sex or the sharing of dirty needles. HIV can develop into auto-immune deficiency syndrome (AIDS), which weakens a person's immune system to the point where the body can no longer fight off infection. Although the death rate of HIV/AIDS has dropped significantly in the past decade, it still killed an estimated 1.6 million people in 2012, according to WHO.
HIV is a worldwide health concern, but Tyndall says that given the public awareness of it, he says he "can't remember seeing a return traveller who contracted HIV."
He acknowledges that "there's a lot of risky behaviour that people engage in," but when it comes to HIV, he advises travellers to simply use common sense.
"Whether you're in Canada or Nairobi, you probably don't want to have unprotected sex with people you don't know."