Traveling in other countries, especially third world countries where standards of air and water quality, food handling, as well as local disease vaccination rates and vector control, may be lower (or poorly enforced) compared to the U.S., can make staying healthy a challenge. This post will discuss the various aspects you should be concerned with to prevent getting infectious diseases while traveling. Part 2, here ,talks about preventing food and water-borne infections. Part 3, here, discusses preventing illness from environmental dangers.
Vaccinations and Preventive drugs
As mentioned in my post on pre-trip health preparations <here>, the first thing you should do before you leave is make sure you get any recommended vaccinations and preventive drugs (such as anti-malaria drugs) for the countries and areas you are plan to visit. Good sources of information on what you need are available at the CDC Travel website here and at the IAMAT website here. Be aware that not all vaccines are 100% effective at preventing you from getting the disease they are intended to prevent. Even vaccines listed as “highly effective” are often only about 90-95% effective, so there is still some chance that you can get infected.
Become Informed about Diseases
While you are on the CDC or IAMAT websites, you should take the time to become informed about the various diseases which you are trying to prevent, just in case your vaccines are ineffective. You should also become informed about the diseases which commonly occur in your destination country for which there are no vaccinations available. It’s important to at least be aware of some of the initial symptoms of these diseases because some of them, such as Chagas disease (common in Latin America), often show very mild symptoms in the initial stages and, if ignored, have serious health consequences in their later stages. If you have an early symptom, such as a swollen eyelid, which can occur as an early symptom of Chagas, you may just think that it’s just an eye irritation, rather than a symptom of a serious disease, and not seek medical attention at a stage when it could be most beneficial.
Some of the diseases without vaccines include: Chagas disease (American trypanosomiasis), Chikungunya, Dengue, Cytomegalovirus, HIV/AIDS, Hookworm infection, Leishmaniasis, Malaria, Respiratory Syncytial Virus, Schistosomiasis, Zika, West Nile Virus. Malaria is “sort-of” covered with drugs that prevent the Plasmodium parasite from setting up shop in your body, but most of the rest you need to try to prevent with good sanitation, watching what you eat and drink, practicing safe sex, mosquito (and other insect) avoidance measures, etc. The CDC website mentioned above does not go into details about diseases which have no vaccinations available, but the IAMAT website does. For example, the CDC website does not list Chagas as a risk in Guatemala, but the IAMAT website does.
Mosquito Prevention
If you are traveling in countries with tropical climates and will be spending any significant time below 6000-6500’ in elevation, then you need to be concerned about mosquitoes. Mosquitoes carry a potential smorgasbord of the world’s most harmful diseases, several of them without vaccines available (e.g. Dengue, West Nile Virus, Chikungunya, Zika Virus). The only thing you can do to prevent becoming infected is avoid getting bitten. You need to carry and apply “effective” mosquito repellent for this purpose and avail yourself of any other active measures to reduce the chance of mosquitoes biting you, such as wearing loose-fitting long sleeved shirts and full length pants (preferably light colored), using mosquito netting (at least 285 holes per square inch) around your bed, and so on. Different mosquito species feed at different times of the day, so you can’t really let your guard down at any time, but the worst period seems to be dusk through sunrise. The most often recommended mosquito repellents contain DEET or Icaridin (also called picaradin, KBR 3023, or trade names Bayrepel and Saltidin), usually in at least 20% concentration. Icaridin is claimed to be just as effective as DEET in the 20% concentration without the skin irritation problems of DEET. The CDC also lists IR3535 and some oil of lemon eucalyptus and para-menthane-diol products as effective against West Nile Virus mosquitoes, but it didn’t see mention of whether these products are also effective against other mosquito species. Mosquitoes are attracted to scented soaps and lotions, deodorants, perfume and after-shave lotion so avoid using these.
In mosquito-endemic areas, often mosquito bed netting will be provided, but if you are going to be staying in a mosquito zone for a long time and are concerned about being protected in situations where the netting isn’t available, or is inadequate (torn, holes too large, too small, etc.), you should consider bringing your own travel mosquito bed net. There are many models available ranging in weight from 8 oz to several pounds. Make sure you get one that is large enough and that can seal or tuck under the mattress. There are double-size nets for couples. There are also fully enclosed mosquito tents available, usually for a single person. A mosquito net also provides some protection against other types of bugs, such as ticks, flies, spiders and beetles, some of which may also be disease carriers. You can increase the effectiveness of your mosquito netting by coating it with an insecticide, such as permethrin. You may also use permethrin on your clothing as well. Mosquitos may bite through thin clothing, so spraying clothes with repellent containing permethrin and\or repellent will give extra protection. In fact, U.S. military personnel treat their uniforms with permethrin in malaria-endemic areas. Of course you still need to apply repellents to any exposed areas of skin that you can’t monitor easily (such as your face).
My personal experience with long term use of strong DEET solutions in Alaska, where the mosquitoes are so large then can bite through a couple layers of clothing, is that I want as little on my skin as possible. In Alaska, we wore the same outer layer shirts and pants every day and these were impregnated with DEET from multiple applications. If I’m traveling in a bad mosquito zone, I’ll most likely try to adopt a similar practice, with one light colored long sleeve shirt and pair of trousers dedicated as my anti-mosquito outfit, sprayed with repellent and maybe permethrin as well, so I can keep the stuff off my skin as much as possible.
The IAMAT website has a very thorough downloadable whitepaper, available here, on how to protect yourself against malaria which I recommend you download and read.
Other Insect-borne diseases
In addition to diseases which are spread by mosquitoes, there are also a variety of diseases which are carried by other insects. Chagas disease is spread by the assassin or “kissing” bug. Lyme disease, Typhus Fever, and Tick Borne Encephalitis are carried by ticks. Sleeping sickness is spread by Tsetse Flies, Filariasis is spread by Deerflies as well as mosquitoes, and Leishmaniasis is spread by Sandflies. Plague is carried by fleas. It may seem like with all these potential insects that can infect you that you don’t stand a chance, but most of the same methods you use to prevent mosquito bites, such as treated insect netting and wearing loose fitting long sleeve shirts and pants, will also help prevent getting bitten by other bugs as well. To increase your protection, you can avoid going barefoot and wear socks and closed shoes, rather than sandals, when walking around away from the beach or swimming pool. In tick-infested areas, don’t wear shorts or skirts and tuck trousers into socks so ticks can’t crawl up your legs and bite you. Treating your clothing with permethrin and\or repellents is also a good idea.
Another practice you can follow to detect ticks that have buried themselves in your skin or see evidence of bites from other possibly infection-bearing insects is to do a nightly skin survey. In order to be able to examine your back or other hard-to-inspect areas you can have your partner help with the inspection or carry a small mirror. Look for any spots of redness, rash, or swelling, especially occurring in a circular pattern, or surrounding any suspicious bite marks on your skin. If you see an area like this, get it checked out by a doctor. For several insect borne diseases you may have secondary symptoms of fever, malaise, muscle aches, nausea, stiffness, etc. If you find that you are feeling poorly within a week of seeing skin symptoms of a possible bug bite, definitely get yourself to a doctor. Diagnosis usually requires blood tests.
Diseases Transmitted by Blood or Body Fluids
Finally we come to diseases that you get by contact with blood or body fluids from another person. These include HIV/AIDS, Hepatitis B and C, Human Papillomavirus (HPV), Genital Herpes, Trichomonas Vaginalis, Chlamydia, Gonorrhea, and Syphilis.
The rate of HIV/AIDS infection in the U.S. for adults age 15-49 is about 0.6%. In many developed countries the rates are much lower. However, in some countries in Africa, HIV/AIDS rates for this age group range as high as 28%. The chance of HIV transmission, from both homosexual and heterosexual contact, is very high in these places. Africa isn’t the only place that has higher rates of HIV/AIDS. There are number of countries with HIV/AIDS infection rates 2-5 times higher than the U.S., so in general it’s always a good idea to practice safe sex, using a condom, with any partner whose sexual history you don’t know and trust. This will also protect you from transmission of all the other sexually transmitted diseases on the list as well.
HIV is transmitted by blood, semen, rectal or vaginal fluids, or breast milk. In order to infect someone, these fluids must come in contact with a person’s mucous membrane (inside of the rectum, vagina, penis, or mouth) or damaged tissue or directly injected into the bloodstream. HIV is not spread through saliva. There is no vaccine available for HIV.
Hepatitis B (HBV) vaccination is required for children in the U.S., so the rates of HBV are very low in our country (about .27%), but rates in many other countries are much higher. For example, the rate is about 11% in Vietnam, 5.5% in China, 6.4% in Thailand, 4.7% in Belize. There is a vaccine available for HBV which is about 90% effective
Hepatitis B (HBV) is 50 to 100 times easier to transmit sexually than HIV. HBV can be found in vaginal secretions, saliva, or semen. It can be transmitted by oral sex, but there are no documented cases of transmission by kissing. However, if HBV is present in saliva, it is assumed that the possibility exists to transmit it through deep kissing.
Hepatitis C (HCV) is transmitted through contact with an infected person’s blood, so it is less easy to transmit. There is no vaccine available for HCV.
The other way these diseases can be transmitted is through blood transfusions and sharing of needles from intravenous drug use. I won’t address the intravenous drug issue, other than to say, if you are a drug user, don’t share needles. Blood transfusion is a more serious issue. If you are injured in a low-income country and you require a blood transfusion you are rolling the dice on potentially receiving a serious disease along with your blood transfusion.
According to WHO, which reported on blood collection in 164 countries, 97% of high-income countries screen blood donations following basic quality procedures for transfusion-transmissible infections (TTIs) like HIV, hepatitis B and C, and syphilis. In medium-income countries, the number is 82%, and in low-income countries, 53%. In 39 countries, blood donations are not routinely tested for transfusion-transmissible infections. According to WHO, the prevalence of TTIs in blood donations is as follows, by country income groups:
| COUNTRY TYPE | HIV | HBV | HCV |
|---|---|---|---|
| High Income | .003% | .030% | .020% |
| Medium Income | .120% | .910% | .320% |
| Low Income | 1.08% | 3.7% | 1.03% |
Unfortunately, if you require a transfusion to save your life in an emergency situation, there’s not really much you can do about the quality of the blood you are receiving. If you are living long-term in a country with poor blood quality testing you may be able to arrange to donate and store some of your own blood against the possibility that you need a transfusion at some point. Blood donation in general is much less common in low-income countries, so often the blood supply is poor to begin with, particularly for more rare blood types.
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