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Ward off the travel bugs

The Straits Times (5 February 2015) - A 45-year old Singaporean, MJ, had booked a 10-day trip to South Africa for herself, her husband, 12 year-old son and 10 year-old daughter. Three weeks before her departure date, she came to Tan Tock Seng Hospital with her children for a travel medicine consultation.

She had to decide if they should cancel their trip because of the Ebola outbreak or, if they chose to go ahead, be advised on the vaccines that would be needed. She had done some research online and was also concerned about malaria.

In travel medicine, destination is everything.

WHERE YOU GO, WHAT YOU DO

As doctors, we want to know where the traveller is going and what he intends to do there because it affects medical recommendations.

When it comes to Africa, however, it is an entire continent. Disease risks are very different if you are in Timbuktu, Mali, versus Nairobi, Kenya – just as risks would be different in rural Cambodia compared to urban Singapore. Similarly, activities planned vary widely.

Business travellers may spend most of their time in meetings, but volunteers visiting an orphanage may get exposed to infections such as measles or pertussis, which may be more common in countries with gaps in national immunisation systems.

 

To address MJ’s question on Ebola, the Ministry of Health here advises postponing non-essential travel to Ebola-affected countries in West Africa. However, the Ebola outbreak is concentrated in three countries: Guinea, Liberia and Sierra Leone. Sporadic cases have spread to surrounding countries such as Mali, Nigeria and Senegal.

There are no Ebola travel advisories for South Africa at this time, although situations can change. Fortunately, it was not necessary for MJ to cancel her family trip.

They were flying to Capetown and spending four days on the beach. Then it was on to the Zimbabwe-Zambia border to see Victoria Falls, before a three-day safari in Kruger National Park. Their itinerary meant there would be some exposure to malaria for a segment of their travels.

YOUR MEDICAL HISTORY

The other part of the travel medicine consultation addresses one’s age, gender, medical history and allergies.

MJ and her husband are in their 40s, while their two children are in primary school.

Malaria is more severe in very young children under five years old and pregnant women.

Those with G6PD-deficiency (a genetic disease) may be more difficult to treat if they get infected with the vivax species of malaria.

This is because treatment includes primaquine, a medication that can cause red blood cell damage in people like them.

Older people are routinely advised to be vaccinated against influenza annually, and pneumococcus once, if they are over 65 years old.

But if a traveller has diabetes or chronic heart, lung, kidney or liver problems, he may need these vaccines even before 65.

Recommendations for vaccines also depend on the vaccines a person had received previously.

If you are travelling to a developing country, you should get jabs to protect you from hepatitis A and typhoid, which are infections spread by food and water.

If you have not had the tetanus vaccine within the past 10 years, getting a booster shot is important if you think you may sustain injuries while outdoors, as tetanus spores in soil can enter the body even through minor skin abrasions.

Travellers should make sure they are up-to-date with their childhood vaccines, such as hepatitis B, measles, mumps, rubella and polio.

Some vaccines are recommended only for specific destinations. For example, a yellow fever vaccine is required if one is travelling to countries in Sub-Saharan Africa and South America, where the disease is still active.

The meningococcal vaccine, on the other hand, is needed for those going to the meningitis belt of Africa, and for Haj and Umrah pilgrims to Saudi Arabia.

Japanese encephalitis, as well, is a mosquito-borne infection which long-term travellers to rural parts of Asia are at higher risk of contracting, so they should get vaccinated against it.

Then, there is a three-dose vaccine for rabies that protects people before they get bitten by a rabid animal – two more doses are required if they are bitten. These injections can potentially save lives, given that this viral infection still kills nearly everyone who is infected.

In the case of MJ and her family, and others going on a similar trip, assuming they are all healthy, doctors would generally recommend vaccines for hepatitis A, typhoid and influenza, as well as ensure they are up-to-date with their vaccinations for tetanus. There is no commercially available vaccine for malaria, but preventive medications, such as Malarone (atovaquone/proguanil), would be recommended to cover their potential exposure to the disease at Kruger and Victoria Falls.

For a five-day exposure, 13 days of Malarone would be needed, starting one day before they reach the risk area, up till seven days after they leave the area.

Singaporeans travel for business, pleasure and volunteer work. More than five million people live here, but we also welcome more than 45 million passing through Changi Airport every year. Many infections can be prevented by vaccines.

Food and water precautions, and personal and traffic safety are also important issues to be aware of when overseas.

With good travel medicine advice, I hope people can travel safely and come home with wonderful memories.

Bon voyage!

Associate Professor Lim Poh Lian is the head of the Department of Infectious Diseases at Tan Tock Seng Hospital, the flagship of the National Healthcare Group, the Regional Health System for central Singapore. 


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Source: The Straits Times © Singapore Press Holdings Limited. Reproduced with permission.