Madeline King, PharmD, BCIDP
Jeanine Abrons, PharmD, MS, FAPhA
At the end of this case, students will be able to:
- Identify risk factors for common parasitic and vector-borne infections in travelers
- Describe common parasitic and vector-borne infections in travelers
- List common prophylactic measures for parasitic and vector-borne infections
- Recommend appropriate treatment regimens for a patient with a parasitic infection
Every year there are more than 700,000 deaths from parasitic and vector-borne (transmitted from mosquitos, ticks, and flies) infections. Common examples include malaria, dengue, schistosomiasis, human African trypanosomiasis, leishmaniasis, Chagas disease, yellow fever, Japanese encephalitis, and onchocerciasis.1 The burden of these infections is highest in tropical and subtropical areas and disproportionately affects the poorest populations. Some diseases, such as Chikungunya, leishmaniasis, and lymphatic filariasis cause chronic suffering, life-long morbidity, disability, and occasional stigmatization.2-4 Vector-borne and parasitic infections can be a significant concern for international travelers of all ages.5,6 Up to 80% of people who travel to low- to middle-income countries may acquire a travel-related infection, making these infections relevant for healthcare professionals based in the United States as well. A lengthy list of different parasitic and vector-borne diseases is available in the Centers for Disease Control and Prevention (CDC) Yellow Book,5 as well as the World Health Organization (WHO) resources on vector-borne diseases.7
Specific vectors and parasites may be endemic in certain regions based on climate and the availability of filtered water and proper sewage systems. Variability of the climate may result in vector/pathogen adaptations and expansions impacting vector-host interaction, host immunity, and the evolution of these pathogens. According to the WHO, factors such as the lack of source control can be a factor in enhancing the risk of vector-borne infections, including poorly designed irrigation and water systems, poor waste disposal, and water storage.7 Additionally, factors that impact the usage of land such as deforestation and loss of biodiversity can contribute to the potential risks. Beyond these factors, socioeconomic/cultural factors, practices regarding pest control, and access to healthcare can influence the prevalence of these diseases.5,7 Parasites can often be ingested through contact with contaminated water (e.g., swimming pools/recreational water) or through consuming contaminated food.5
Basic prevention strategies for parasitic infections include maintaining appropriate hygiene, including the frequent washing of hands when handling, preparing and eat food, and after using the bathroom. When water is not an option, hand sanitizers with greater than 60% alcohol content can substitute. Adjustments in diet may also be recommended to lessen exposure, such as only using bottled water (for drinking as well as brushing teeth) and only consuming foods cooked to recommended internal temperatures (avoiding raw produce which may have been exposed to unsafe water). For prevention of vector-borne illness, the use of insect repellents endorsed by the Environmental Protection Agency (EPA) is recommended,8,9 as well as the use of protective clothing and barriers (e.g. long-sleeved shirts, long pants, treated clothing and gear). Patients can be counseled to stay in indoor, air-conditioned areas as much as possible to reduce risk, and when available, to stay where screens (without holes) are present on windows/doors. When screens are not available, patients should be counseled to sleep under a mosquito net (which can be purchased prior to travel) that is WHO Pesticide Evaluation Scheme (WHOPES)-approved and long enough to tuck under mattresses; permethrin-treated nets can provide additional protection.5,8,9
CC: “I am traveling to Peru this summer and want to make sure I have the vaccines I need.”
HPI: FP is a 35-year-old woman who presents to the clinic. She is traveling abroad and seeks your advice related to vaccines and prevention or prophylactic strategies for parasitic and vector-borne infections during her upcoming international trip.
PMH: Asthma (controlled); allergies (seasonal)
- Never smoked
- No history of illicit drug use
- Consumes alcohol occasionally in a social setting
ROS: No complaints today
- Fluticasone/salmeterol 100/50 mcg one puff twice daily
- Fexofenadine 180 mg once daily
Allergies: NKDA; seasonal allergies to pollen
- Up to date on all her childhood immunizations
- Received Vivotif nine and two years ago before traveling to India
- Received Hepatitis A and yellow fever vaccines nine years ago before traveling to Egypt
- Receives an influenza vaccine yearly and PPSV23 pneumococcal vaccine 11 years ago
SDH: FP and her partner (MS) are traveling to Peru together for three weeks this summer. MS was born in Peru and moved to the United States as a teenager, with her family. FP was born in the United States and has traveled to several countries outside of the United States but not to Peru. FP works as a history professor for a university, while MS is an emergency medical technician. They do not have any children. MS does not believe she needs any vaccinations or prophylaxis because she was born in Peru and does not expect to acquire any infections there.
1. What vaccinations do you recommend for FP today?
2. Does FP need any malaria prophylaxis while in Peru? If so, what will you recommend?
3. Should you ask that FP’s partner MS also makes an appointment? Why or why not?
4. What non-pharmacological travel health recommendations are reasonable to recommend to FP and MS?
5. What other counseling should you provide on medications as well as travel safety?
Pharmacists have a vital role in patient education, disease prevention, and public health because of their unique position to educate patients and provide vaccines, as well as antimicrobial travel prophylaxis. Pharmacies may be more readily accessible to patients than clinics or health departments. With more people traveling for pleasure, business, or volunteer work, there is a greater need for accessible travel health information.
Pharmacists are also responsible for preparing and dispensing prophylaxis and treatment of parasitic infections to patients. It is important for the pharmacist to recognize which agents are preferred, and which may be contraindicated in certain patients (e.g., children). They will also need to provide counseling on the proper use of medications, including how they should be taken or applied and any side effects the patient should expect. Pharmacists in community pharmacies are in a unique position to talk to their patients at the time of prescription request or pick-up. If a patient were to ask for an override from their insurance because they are traveling, the pharmacist would be able to talk to the patient about their travel plans and travel health on the spot. They could schedule vaccines, contact providers (if necessary) to ask for prescriptions, and discuss over-the-counter (OTC) considerations like insect repellant. In addition, pharmacists who work in facilities where they have collaborative practice privileges or prescribing authority can schedule visits with patients themselves. This, again, makes it easier for patients to see someone prior to travel in the case that it takes longer to make an appointment with their primary care physician.
Patient Approaches and Opportunities
Pharmacists are uniquely positioned to educate travelers about diseases endemic to areas they plan to visit. Vaccines, OTC and prescription-based products, and non-pharmacological strategies for prevention should be discussed. Insurance coverage of some pharmacological therapies may be variable and should be discussed with patients. Other factors such as side effect tolerability and the ability to adhere to the dosage duration should be considered. Behavioral strategies to lessen the potential for vector bites should be stressed,6 and patients should be instructed on what products need to be bought in advance and what factors should be considered when selecting travel accomodations.1,5,7 Clinicians should encourage patients to avoid uncooked and undercooked foods and unfiltered water.1
Pharmacists’ care opportunities in vector-borne and parasite illness are not limited to pre-trip prophylaxis. Upon return from travel, patients may seek guidance from pharmacists in the community setting for selection of OTC products for new onset or mild symptom management. Alongside open-ended questions to obtain information about symptoms, pharmacists should inquire about recent travel to fully understand the potential differential. For patients who have traveled, trip details such as types of areas the patient visited (urban vs rural), the nature of accommodations/modes of transportation, food/beverage consumption, recreational activities, sexual activity, and tattoos or piercings acquired during travel are important.
Related chapters of interest:
- Ethical decision-making in global health: when cultures clash
- The cough heard ‘round the world: working with tuberculosis
- Sex education: counseling patients from various cultural backgrounds
- Centers for Disease Control and Prevention. Parasites. 2021. . Accessed March 2, 2021.
- Fischer LS, Mansergh G, Lynch J, Santibanez S. Addressing disease-related stigma during infectious disease outbreaks. Disaster Med Public Health Prep 2019;13(5-6):989-994.
- Smith RA, Hughes D. Infectious disease stigmas: maladaptive in modern society. Commun Stud 2014;65(2):132-138.
- Perry P, Donini-Lenhoff F. Stigmatization complicates infectious disease management. AMA J Ethics 2010;12(3):225-230.
- Griffin PM. Hill V. Chapter 2 – Preparing international travelers: food and water precautions. CDC Yellow Book 2020: Health information for international travel. . Accessed March 9, 2021.
- Centers for Disease Control and Prevention. Division of Vector-Borne Diseases. Prevent tick and mosquito bites. . Accessed March 2, 2021.
- World Health Organization. Vector-borne diseases. . Accessed March 2, 2021.
- US Environmental Protection Agency. Repellents: protection against mosquitoes, ticks, and other arthropods. 2013. . Accessed March 2, 2021.
- Centers for Disease Control and Prevention. Traveler’s health: avoid bug bites. . Accessed March 2, 2021.