Welcome back, the goal of this section is to provide you with an overview of vector-borne diseases, how they affect travelers and what you can do to prevent them while you're travelling. We may discuss some clinical presentations of disease, but that's really not the most important part. I mean, the goal of this is not for us to be clinicians and to start diagnosing ourselves, but rather to be a little bit aware of what's going on and maybe when you should seek care. What I really want you to take away from this section, though, are the risks that are associated with different vector-borne diseases, knowing where and how you might become infected, and really how to stop that from happening is the most important takeaway. In this section, we'll be talking more specifically about Malaria, Yellow fever, Dengue, Japanese encephalitis, and Schistosomiasis. And some of these are far more common in travelers than others, but your risk profile will help you to determine which of these you should be concerned with. And remember that while all of these might not be applicable to your most impending travel, it may be applicable in the future. So for each of these, we'll be discussing transmission, the when, where, what, and how of things and then, most importantly, prevention. Is there prophylaxis that's available, medications that you can take to make yourself feel better, vaccinations and what can you do from a behavior side of things to prevent yourself from getting ill? The first vector-borne disease that we will talk about today is malaria. But, I'm not going to go over the ins-and-outs of the parasite life cycle, because you've likely had that information, or you'll have it in other courses, or really it's just not relevant to travel health. It's most important for you to know where malaria is prevalent and how travelers most often get it. I want to start with a quick question. In how many countries is malaria prevalent? And while you're thinking about this, I want to emphasize that, for those of you who have lived in or are born in malaria endemic countries, this is still a really important section and question for you. Because oftentimes if we are continuously exposed to or very used to a specific risk, we saw viewing it as a risk. But malaria is still a risk, even if you've lived in a malaria endemic country for a very long time. So how did you answer? Well, the answer is in 96 countries. And you can see on the image on the right that we're really following that southern hemisphere band, right? You see it in Latin America, especially Sub-Saharan Africa there. And the greatest risk for travelers in getting malaria is in Sub-Saharan Africa. So, for those of you who are traveling to or considering traveling to Sub-Saharan Africa, this section is really relevant for you. And then, of course, you can see in India as well in other parts of Southeast Asia. The first thing I want to talk about as we discuss malaria prevention is malaria chemoprophylaxis. Here I've listed three of the major prophylaxis options that are available to you. And there are others that are available. But we discuss them a bit less because many of them, there's resistance to that prophylaxis in most parts where that prophylaxis used to be very useful. So the most common Chemoprophylaxis that are available are Malarone, Lariam and Doxycycline. In here, I've listed some of the pros and cons of each of these drugs. Not all but the major ones that you should think about as you go in and talk to your travel doctor who will, of course, give you a lot more information about what you should be considering. So Malarone is what I tend to take because it's good for last-minute travelers. You don't have to start taking it a long time before you travel. And side effects are fairly uncommon or at least very rarely severe. So I like that, that I'm not going into taking a medication that could have major side effects. The down side is that you do take it daily and then, because you take it daily, it might be more expensive. Lariam is one of the few Chemoprophylaxis that can be used during pregnancy. And you'll only have to take it weekly, which is nice. But you can't take it in some areas due to resistance. And it is known for having psychiatric symptoms, most commonly is night terrors. And so for those people who have a history of mental health issues, even family mental health issues, they themselves haven't had it. You might want to stay away from Lariam, or at least have a more in-depth conversation with your doctor. And then Doxycycline tends to be the least expensive option, which makes it more appealing to students. But one of the largest issues with it is it does increase sun sensitivity. And for those of you who are travelling towards the equator, this can be actually a really big issue and can really be uncomfortable. It can make your eyes more sun sensitive and can make you more likely to burn. It can also cause upset stomach and you have to continue it for about four weeks after travel. Please remember that most of the protective effects don't begin immediately. So, you need to start medication in advance of your travel. And travel doctors will be able to talk you through all of this again. But, remember that many providers, like your normal medical providers, don't regularly encounter travelers who are seeking malaria prevention. So, they might not be as familiar with appropriate dosing and side effects. So, this section is really about getting you prepared to talk to your travel doctor or to your regular doctor. All right, so that was a long winded way of talking about the different prophylaxis. But when you're considering which one is most appropriate for you, think about how well you remember to take you medications, what's more right for you daily weekly, your mental health state and history, right? That's really relevant for Lariam. Sun sensitivity and if you have it already or if it's a major concern for you. And then I think it's important to also think about cost and what your insurance will cover, because different insurances will or will not cover some, all, none, of these medications. So please have conversations with your insurance company early on about what they will actually cover. And I want to also encourage you to always purchase your medications from a trusted source, preferably prior to travel. And if you are a US citizen or you are living in the US, I'd recommend purchasing it here or from your home country. Whatever you feel most comfortable with. There is advice out there that you can save money by purchasing prophylaxis once you get to your site, wherever that is. And that's true, oftentimes those medications are cheaper, once you are in your location. The problem is that there aren't as many regulations around counterfeit and substandard medications. So just be aware that that advice is out there. And of course you can choose where and when you want to purchase your medications. But the advice I would give is to purchase it prior to travel, especially since you need to start your medication before you are actually exposed to a malaria epidemic area. So chemoprophylaxis is one of the best ways to prevent malaria, but it's not 100% effective. None of them are. So in combination with the prophylaxis, you should also be using these other protection methods. Including using bed nets at night because malaria mosquitoes are night biting, bug spray at dawn and dusk whenever you're going out. You an always choose to have permethrin treated clothing if you would like that added protection. And I absolutely recommend long sleeved clothing, particularly at nighttime because it really does help to prevent mosquito bites. And just remember that there is no vaccine, so the best way of preventing malaria is a combination of chemoprophylaxis and behavioral methods. Now, let's talk about yellow fever. Yellow fever occurs in urban and rural areas of Africa and Central and South America. You can see on the map here the band where yellow fever is located. What I really want to talk about with yellow fever is the vaccination and how it's an entry requirement for many countries. So please don't forget to one, get your yellow fever vaccination and two, bring your yellow fever certification card with you whenever you travel. Often time country rules are that you need to have your card if you're traveling from one yellow fever endemic country to another one. But, really I recommend that you always carry it whether you're coming from the US, or Europe or a non yellow fever endemic country, it doesn't matter. Just always carry it with you because you'd really hate to get stopped at the border and not be allowed entry. And some countries may deny you entry without one. And others might require that you get the vaccine again in the airport if you fail to show your card. And I don't think anybody wants to go through having to sit there at customs getting their vaccination again. Yellow fever illness in travelers is very rare. But this is due, in large part, to vaccination efforts and to those vaccine requirements. The yellow fever vaccine is recommended for people nine months and older. So that should be everyone in the class, who are traveling to or planning to live in high-risk yellow fever areas. And regulations now stipulate that the vaccine protection is valid for the duration of the life of the person who is vaccinated. So it used to be about every ten years you needed to get, revaccinated but that's not the case anymore. And then your certificate of vaccination becomes valid 10 days after you get the yellow fever vaccination. So, make sure you are not trying to do it the day before you leave. Dengue fever is another vector-borne disease, another mosquito born disease just like malaria and just like yellow fever. Dengue fever is often called breakbone fever just because of the amount of pain that people experience in their bones and joints when they have it. It's a viral illness that's spread through mosquito bites. And those who are most at risk are travelers to tropical and subtropical regions, including the Caribbean and those in urban areas. So Dengue mosquitos really tend to prefer urban areas. It's one of the few where you find them, they're urban biters. Mosquitos carrying Dengue bite during the day and night, indoors and outdoors in urban areas where they're found. And so they're really quite everywhere, which makes prevention a bit of a pain and something that you have to think about more. The World Health Organization has endorsed the first ever vaccine for dengue fever. Which is huge, I mean this is a really big deal in the global health community. But it's meant at this time for people who are over the age of nine who live in endemic areas, and who have likely been exposed previously. So there's not a vaccine that's available for travelers right now. Because there are four stereotypes of Dengue, the biggest risk is really getting it more than once. So the first time you get it, it sucks, it's no fun. The second time is even worse. So prevention methods for Dengue include using bug spray with Deet, treated clothes using bed nets because they bite at night as well as during the day and then staying in screened in or air conditioned places. And that's because they're day biters. It's important to remember with Dangue that there is no chemopropholyaxis, there is no treatment and there is no vaccine for travelers. So this is really one of those vector-borne diseases where you have to think about your behaviors and what you personally can do on a day to day basis to prevent getting bit by mosquitoes. All right, so we're going to move on to Japanese encephalitis, another mosquito born disease. Japanese encephalitis is the leading cause of viral encephalitis in Asia. And it principally occurs in rural, agricultural locations, mostly during the rainy season. And you can see on the map to the right of your slide that Japanese encephalitis is really found in Asia and occurs in almost all Asian countries. Your risk of getting Japanese encephalitis varies greatly based on how long you're going to travel, the season you're traveling in, and location. So unlike Dengue, but you're not really at risk for JE if you're in an urban area. But the more rural, agricultural areas that you are, the higher that your risk goes up. And the greatest prevention methods for JE are to avoid mosquito bites and to get vaccinated. Though this is another one where you have to think about the cost of vaccination because the JE vaccine can cost quite a bit. So who should get vaccinated? Again this is based on your risk profile. It's those who are planning to visit rural farming areas in countries with Japanese encephalitis. Or those who are planning to visit countries where a recent Japanese encephalitis outbreak has occurred. The interesting thing about the vaccination for JE is that allergic reaction may occur up to two weeks after the vaccine is administered. So again, you're going to want to make sure that you leave enough time for the vaccination prior to travel just like yellow fever. Schistosomiasis is really the odd bird in this section, because it's the only disease we're talking about here, that's not mosquito born. In fact, schistosomiasis is a helminth parasite that's transmitted in contaminated bodies of fresh water by snails. So it's a weird one. Most travel associated schistosomiasis is found in sub-Saharan Africa. And sites in Africa that are frequently visited by travelers are common sites of infection. So if you think about major rivers and water sources that you might live near or might travel to for fun, like the Nile River, Lake Malawi, Lake Victoria, these are places where there's definitely schistosomiasis, regardless of what the local claim is. So I've been to a couple of these sites where the people living there or tourist companies that are running there, claim that there's no schistosomiasis in the fresh water that's there. But anybody of fresh water in sub-Saharan Africa may have schistosomiasis. So just think about that as you do your rafting or water testing, whether it's work or pleasure, be mindful. For schistosomiasis, there is no vaccine that's available and there's no prophylaxis that's available. And prevention just really includes avoiding bodily contact with freshwater in endemic countries as I talked about on the previous slide. There has been some research that DEET repellents can block penetration of the parasite. But this is short-lived and it's not necessarily reliable, so I wouldn't suggest covering yourself in DEET bug spray, and hoping into fresh water. If you're going to go swimming, please just be aware that schistosomiasis is in the area. And take precautions, talk to your travel doctor when you return. And just be mindful that any body of fresh water may have schistosomiasis. The most important things to take away from this section are that prophylaxis and vaccines are available for some vector-borne diseases, but not for all. And that, when there is a vaccine available, or prophylaxis available, it's not always 100% effective. And so those are best combined with other prevention methods that we talked about including avoiding exposure to the Using Deet bug Spraying treating your clothing and always using bed nets. And please, as you travel, don't forget your yellow card if you're going to any country. Just always take your yellow card with you.
