Travel-Related Infections: Risks for International Travelers
Passengers traveling abroad are at risk for various infectious diseases. Travel-associated infections are particularly common among those traveling to developing countries.
Health problems commonly encountered in travelers to developing countries include diarrhea transmitted through the fecal-oral route, hepatitis A, typhoid, cholera, polio; yellow fever, Japanese encephalitis, malaria due to mosquito bites; meningococcal meningitis, influenza, legionellosis; hepatitis B, C, HIV through sexual contact, exposure to blood and body fluids; tick-borne encephalitis, rabies due to tick bites, and dog bites.
Before traveling, routine vaccinations tailored to the traveler’s age and underlying health conditions should be administered. These vaccines include tetanus, diphtheria, pertussis, Haemophilus influenzae type B, measles, mumps, rubella, chickenpox, pneumococcal, and influenza vaccines. Vaccinations for hepatitis A and B, polio, typhoid, Japanese encephalitis, tick-borne encephalitis, and rabies are recommended for situations involving travel-related risks. Mandatory vaccinations are necessary before going to specific regions where certain infections are endemic (Table 1).
| Routine recommended vaccinations | |
| Tetanus-diphtheria-acellular pertussis (TDaB) | TDaB is administered to children in 5 doses (one dose at 2, 4, 6, 18 months and one dose at 5-6 years of age). In adults, a booster dose of TDaP is given at age 19 and Td is repeated every 10 years. |
| Haemophilus influenzae tip B | It is administered to children in 4 doses (1 dose each at 2, 4, 6 and 18 months). Those who underwent splenectomy after the age of 19 are administered 1 dose 15 days in advance, those who underwent bone marrow transplantation are administered 3 doses at 1-month intervals 6 months after transplantation, and 1 or 3 doses are administered to other *risk groups. |
| Measles-Rubella-Mumps | One dose of vaccine is administered to children between the ages of 1 and 5, and to adults after the age of 19. Those planning international travel, students and healthcare workers are administered 2 doses of vaccine, 1 month apart (it is not recommended for those over the age of 57 as they are considered immune). |
| Varicella | Çocuklar 1 ve 5 yaşlarında 1 er doz, 19 yaşından sonra bir ay arayla 2 doz aşı yapılması önerilir. |
| Pneumococcal conjugate (PCV13) | In children 2, 4, 6 and 12-15. 1 dose is administered every month. >2 years, >19 years *1 dose is administered to risk groups. |
| Pneumococcal polysaccharide (PPSV23) | Firstly, 1 dose of PCV13 is administered to *risk groups >2 years of age, *risk groups after 19 years of age, and >65 years of age, and 1 dose of PPSV23 is administered 2 months later. *1 dose of PPSV23 is applied again to risk groups after 5 years. |
| Influenza | It is recommended that children and adults >6 months receive influenza vaccination annually. It is held in September-October-November before the influenza season in the Northern Hemisphere, and in January-February-March in the Southern Hemisphere. |
| Vaccinations and recommendations due to risk | |
| Hepatit A | Since there is a risk of Hepatitis A transmission through contaminated water or food for those traveling to developing countries, 2 doses of vaccine (1 dose every 6 months) are recommended. |
| Hepatit B | If there is a possibility of any medical procedure, tattoo, piercing or sexual contact with a new partner, it is recommended to get 3 doses of vaccine (1 dose at 0, 1, 6 months). |
| Polio /Inactivated Poliovirus (IPV) | In children, the 3rd dose is administered at 2, 4 and 6-18 months, and the 4th dose is administered at 4-6 years of age. A single dose of IPV vaccine is administered to those who will go to regions where polio has not been eradicated (Ethiopia, Kenya, Somalia, Syria, Afghanistan, Nigeria, Pakistan, etc.) and those who have previously been vaccinated. |
Rabies | In developing countries, those who will go to risky travel areas for rabies (those doing field work, camping, cycling or backpacking) are given 3 doses of vaccine (1 dose on days 0, 7 and 21) before travel. |
Typhoid | The risk is higher in North and West Africa, southern Asia, Central and South America and the Middle East. A single dose of vaccine is recommended for people >2 years of age who will stay longer than 1 month, especially in areas where the risk of long exposure to contaminated water and food is high and the disease is endemic. |
| Tick-borne encephalitis | It is recommended for those who will stay in Eastern and Central Europe, Siberia’s forested regions and rural areas between April and October, when the risk of tick contact increases. The vaccine is not available in our country. Those who will be camping or working in farms and forest areas should wear a long-sleeved shirt, shirt tucked into trousers, trousers tucked into socks, |
| Japanese encephalitis | Vaccination is recommended for those who will go to rural areas of Russia, China, Japan and the Korean Peninsula during the endemic season and stay for more than a month. The vaccine is not available in our country. Those staying in rural areas should use clothes that cover the body such as long-sleeved shirts, long trousers, hats, and fly repellent sprays. |
| Mandatory Vaccinations | |
| Yellow fever | The vaccine is administered as a single dose 10 days before traveling to risky areas. The protection period is 10 years. For yellow fever, South America (Peru, Ecuador, Brazil, Bolivia and Colombia) and some countries in the equatorial region in Africa pose a high risk. |
| Meningococcus | The disease occurs between December and June in sub-Saharan Africa. Meningococcal vaccination is a condition required by Saudi Arabia for those who will visit Mecca and Medina during the Hajj and Umrah period. |
Risk groups: HIV, kidney disease, splenectomy, chronic heart, lung or liver disease, diabetes patients, cancer patients, immunosuppressive treatment patients, cochlear implant, hemoglobinopathy, multiple myeloma, transplant patients and > 65 years of age.
Table 1. Pre-travel vaccinations and recommendations
Personal hygiene and nutritional precautions: Many travel infections occur through consumption of contaminated food and water. Foods sold openly, foods consumed raw, uncooked or undercooked are not safe. Ice should not be placed in water and beverages. Water and beverages that are closed and in intact packaging should be consumed.
Well-cooked and hot foods or canned foods should be preferred, uncooked-raw, undercooked meat and meat products, and salads with cream and mayonnaise should be avoided. The best method against travel-related traveler’s diarrhea is to “Boil, cook, peel, wash” and if we cannot do these, do not eat or drink any of them.
The most common illness among travelers is traveler’s diarrhea. Diarrhea is seen in 50% of people who travel from developed countries to developing countries for 2-3 weeks. Enterotoxigenic and Enterohemorrhagic Escherichia coli, Campylobacter, Salmonella and Shigella species are the main causative agents.
At lower rates, viruses such as Noroviruses and protozoan Entamoeba histolytica are the causative agents.
Antibiotics are generally not recommended for prevention. Treatment should be arranged according to the results of stool examination and culture, but since such procedures are difficult during travel, those who go to risky areas can carry antibiotics with them upon the recommendation of their doctor.
According to the report of the World Tourism Organization, the 10 most traveled countries in 2013 are France, USA, Spain, China, Italy, Turkey, Germany, England, Russia and Thailand, respectively (Table 2). Türkiye ranks 6th among the most traveled countries.
| Place | Country | International tourist arrivals 2013 (million) | International coming tourists 2012 (million) |
| 1 | France | 84.7 | 83.0 |
| 2 | USA | 69.8 | 66.7 |
| 3 | Spain | 60.7 | 57.5 |
| 4 | China | 55.7 | 57.7 |
| 5 | Italy | 47.7 | 46.4 |
| 6 | Türkiye | 37.8 | 35.7 |
| 7 | Germany | 31.5 | 30.4 |
| 8 | England | 31.2 | 29.3 |
| 9 | Russia | 28.4 | 25.7 |
| 10 | Thailand | 26.5 | 22.4 |
Table 2: According to the report of the World Tourism Organization, the 10 most visited countries in 2013 in terms of the number of international trips.
Malaria is the most common cause of death among infections related to travel. The most risky regions worldwide are sub-Saharan Africa, Oceania (Solomon Islands and Papua New Guinea), and Vanuatu. The risk is moderately high in India and Haiti, while it is low in Southeast Asia and Latin America. Cases of chloroquine-resistant malaria are increasingly prevalent in Central-South America, Southeast Asia, and sub-Saharan Africa.
Chloroquine-sensitive P. falciparum is prevalent in regions such as Mexico, the Caribbean, the western and northern parts of the Panama Canal in Central America, North Africa, the Middle East, and China. Chloroquine-resistant P. vivax is widespread in Indonesia and Papua New Guinea.
To prevent malaria in chloroquine-sensitive areas, chloroquine is initiated one week before traveling with a 300 mg tablet, followed by one tablet per week during the stay and for four weeks after returning. In chloroquine-resistant malaria regions, mefloquine is initiated one week before traveling with 250 mg (one tablet per week) and continued for four weeks after returning. Alternatively, Atovaquone-proguanil (250-100 mg) or doxycycline 100 mg can be started one day before traveling, with one tablet daily during the stay and one tablet daily for four weeks after returning. Additionally, to avoid mosquito bites, reducing outdoor activities at night, wearing long-sleeved clothes and pants treated with permethrin, sleeping in enclosed spaces, and, if not possible, using permethrin-treated bed nets are recommended (safe for pregnant women and children). Insect repellents containing diethyl-meta-toluamide (DEET) are the most effective, although sufficient data on their use in pregnant women are lacking.
For protection against sexually transmitted diseases and potential exposure to HIV and other microorganisms, abstaining from sexual activity or, if not 100% protective, using condoms is the best solution. In addition to avoiding sexual contact, staying away from procedures that pose a risk of exposure to blood and body fluids, such as injections, tattoos, shaving, and haircuts, as well as transfusions, is necessary.
References:
- http://www.seyahatsagligi.gov.tr
- http://en.wikipedia.org/wiki/Tourism
- Recommended Adult Immunization Schedule United States 2015, Mortality Weekly Report (MMWR) on February 5, 2015.
- Recommended Immunization Schedule for Persons Aged 0 Through 18 Years, United States 2015.
- The practices of Travel Medicine: Guidelines by the Infectious Diseases of Society of America. CID 2006;43: 1499-539.
- http://www.cdc.gov/malaria/resources/pdf/clinicalguidance.pdf
- http://www.cdc.gov/malaria/travelers/drugs.html
