Travel medicine
Examples of non-in infectious disease topics to consider before traveling
-Altitude sickness -motor vehicle accident prevention -access to healthcare when traveling -travel and evacuation insurance -letters for special needs
principles of Chemoprophylaxis for malaria
-Drug choices based on predominant Plasmodium species at the destination and the degree of antimalarial resistance -need to factor in the need for chemoprophylaxis, resistance patterns and toxicity risk from drugs -chemo prophylactic drugs are started for travel, taken during the duration of trip, and then taken after return. Timeline depends on the specific drug used.
TD in Latin America
-E.coli -enterotoxigenic, enteroaggregative -resistance +/-
Things to consider when diagnosing travel related illnesses
-Geography -activities undertaken -incubation periods of possible infections -vaccines given or not given -prophylaxis taken or not taken
Determining what risks exist in different parts of the world
-Likelihood of exposure -spectrum of organisms based on location -antibiotic resistance
delayed onset malaria in travelers
-Most antimalarials work on the blood stage of the parasite life cycle -What are the implications for travelers? 35% were late illness > 2 months after return -P vivax or ovale 89% -P falciparum 6% 62% took their prophylaxis
chemoprophylaxis regimens for malaria
-No reported chloroquine resistance → chloroquine weekly -chloroquine resistance reported: → mefloquine weekly →atovaquone/proguanil daily → doxycycline daily → primaquine daily (only with expert advice)
Rifaximin
-Nonabsorbed rifamycin derivative -Comparable to ciprofloxacin in the treatment of travelers' diarrhea caused by noninvasive E. coli in patients ≥ 12 years of age (FDA approved 5/04) -Prevention study in Guadalajara, Mexico 72% effective vs placebo during 2 week course -Safe, well tolerated
yellow fever vaccine
-Only 10-30% of US travelers going to yellow fever endemic areas get vaccinated -Not for age < 6-9 months, pregnant, immunocompromised, or thymectomy -Age > 60 more serious adverse effects
New Malaria
-P. knowlesi -Rapid diagnostics in US (BINAXNow) -Artesunate
Other infectious disease topics to consider prior to travel
-STD risk reduction -rabies (veterinarians, adventure bikers) -Japanese encephalitis (farmers) -healthcare workers (HIV, hepatitis) -cholera (disaster relief workers)
Self-directed therapy for travelers diarrhea
-Strategy that should be used for the majority of travelers -what to use: 1. Loperamide -Rapid control of symptoms -Avoid if bloody stools or dysentery 2. Effective antibiotics: *Fluoroquinolone* -1-3 day course -Most get better after 1-2 doses -Cipro 500 mg BID (Rx #6 for 2 weeks) *Azithromycin* -SE Asia for extended period -Cant tolerate quinolone -500mg BID x 3 d *Rifaximin* -Alternative -400 mg TID x 3d 3. Typically 1-3 day course is sufficient
Core infectious disease topics for travel
-Vaccinations -Travelers diarrhea -malaria prevention
Information healthcare worker needs prior to travel for best advice
-Where's the patient going -what are they doing -what time of year -how long -type of activities -health status (pregnancy, age, allergies, medications etc.)
required pre-travel vaccines
-Yellow fever vaccine may be required for travel to and through countries in Africa and S America -*Meningococcal vaccine* is required for travel to Saudi Arabia during *Hajj*
Mosquito avoidance
-insect repellent -insecticide -avoiding prime feeding times of day
Malaria Deaths Following Inappropriate Malaria Chemoprophylaxis--US, 2001
1. 7 malaria-related deaths from among US citizens who had traveled abroad following inappropriate chemoprophylaxis -All were given chloroquine to be taken for travel to known chloroquine-resistant areas 2. Out of 4685 cases of imported malaria (92-01) -19% took inappropriate regimen -56% took no chemoprophylaxis
Common illnesses that present upon travelers return
1. Diarrhea 2. Upper respiratory tract infection 3. Rashes 4. Fever
NOT TO MISS diagnoses
1. Falciparum malaria 2. Typhoid fever 3. Meningococcemia 4. Rickettsial diseases
Prevention of Travelers diarrhea
1. Prophylaxis 2. Self-directed therapy
3 categories of pre-travel vaccinations
1. Routine adult and pediatric updates 2. Required vaccines for travel (yellow fever) 3. Recommended vaccines for special risk/unique situations
malaria chemophrophylaxis
1. Start before travel -Mefloquine or chloroquine 1 week before -Atovaquone/proguanil 2 days before -Doxycycline 1 day before 2. Take during trip 3. Take after return -4 weeks: mefloquine, chloroquine, doxycycline -1 week: Atovaquone/proguanil -Primaquine terminal prophylaxis when indicated
Reasons for pretravel consultation
1. assess, communicate, and manage risks associated with travel 2. Working knowledge of up-to-date easily accessible resources is key to prevention 3. Risk for acquisition of infectious disease is there only one of the many topics that should be discussed and considered
TD in Asia
-*Shigella, Salmonella, Campylobacter* -Invasive -Resistance +++
mefloquine side effects
cardiac and neuropsych
dengue and yellow fever
daytime mosquitoes
chloroquine
well tolerated
malaria prevention in travelers
-Accurate risk assessment CDC Malaria Hotline 770-488-7788 -Personal protection measures Mosquito bite protection -Chemoprophylaxis
Travelers diarrhea prophylaxis
-A strategy that should be used for the rare traveler -examples of situations where prophylaxis may be warranted: critical nature of trip host factors making a diarrheal illness higher risk -what to use Once daily quinolone (>90%) Once daily or BID rifaximin (72%) Bismuth subsalicylate 2 tabs QID (65%)
3 Rs of travel vaccineS
-*Routine* Adult immunizations up to date? -*Required* Crossing an international border or entering a country requiring yellow fever vaccine for entry? -*Recommended* Any special risks?
Hepatitis A
*#1 vaccine preventable disease in travelers* Average disability ~ 30 days in young adults Mortality up to 3% age over 40 underlying liver disease
Etiology of Travelers' Diarrhea
*Bacteria (60%+)* -E. coli (ETEC, EAEC) -Shigella -Salmonella -Campylobacter -Aeromonas -Plesiomonas *Unknown (20-30%)* *Parasitic (3%)* -Giardia -Cryptosporidium -Entamoeba histolytica -Cyclospora -Rare isospora, Dientamoeba *Viral (10%)* -Norovirus -Rotavirus
Percent of US travelers going to areas endemic for hepatitis A that were not vaccinated
80%
Vaccines and Travel
Beware the VFR -Visiting friends and relatives Accelerated vaccine schedules exist -TwinrixTM 0,7d,21d,1yr (vs 0,1mo,6mo) Pick up where you left off
tools for Assessing malaria risk
CDC website CDC malaria Hotline
Vaccine resources
CDC website yellow book
mosquito avoidance
DEET containing Insect Repellant -35-50% concentration -7-20% Picaridin is a newer option Permethrin-treated bed nets/clothes -Reapply after every 5 washings Long-sleeves and pants -Malaria: nighttime feeder -Dengue and Yellow Fever: daytime feeder
STD risks for travelers
HIV-1 and HBV : everywhere HIV-2 : West Africa, India, Portugal Fluoroquinolone resistant GC Chancroid, LGV, Donovanosis, HSV, syphilis Counsel: condoms, HBV vaccine, risks
other pre-travel vaccines recoomended for certain destinations
Hepatitis A HBV or Twinrix (combined HAV/HBV) Typhoid Rabies Meningococcus Japanese B encephalitis Tick-born encephalitis Cholera
Preventing hepatitis A in travelers
Immunoglobulin: -Antibody present in serum = 2 days -efficacy → 70-80% -duration of protection = 3 to 5 months Vaccination: -antibody present in serum = 14 days -efficacy > 90% -duration of protection >10 years
worst places for TD
Latin America, Africa, Southern Asia 40% risk
places with moderate (15%) risk of TD
N. Mediterranean, China, Russia, Jamaica
Hepatitis A bottom line
ONE SHOT → MAKE IT HEPATITIS A VACCINE 1. Travel anywhere outside of US, W Europe, Japan, N Zealand, Australia, Canada. 2. Give at least 4 weeks before travel -CDC recommends immune globulin for some groups in addition to HAV vaccine if < 2 weeks before travel -WHO does not recommend immune globulin, just single dose HAV vaccine
malaria
Plasmodium vivax, ovale, malariae -Can make you sick -Increasing vivax resistance esp S Pacific Plasmodium falciparum -Can kill you if non-immune -Vast majority of world has drug resistance -Severe complications possible: cerebral malaria, black water fever (massive hemolysis), acute renal failure, ARDS, DIC
HAV vaccines
Primary Booster Havrix™ 1 dose 6-12 mos Vaqta™ 1 dose 6-18 mos One dose = 88% seroconversion @ 2 wks 99% seroconversion @ 4 wks
TD pharmacology
Prophylaxis -This is for the rare traveler or someone who can't afford to be sick Self-directed therapy -Preferred method for majority of travelers
Malaria Endemic countries
Risk of malaria differs markedly from area to area and depends on itinerary, accommodations, time of year and intensity of transmission within the region of travel
Preventing TD
Safe: Steaming hot foods (>59°C) dry bread peeled fruits foods with high sugar content low pH items like citrus juices carbonated drinks Unsafe: room temperature food buffet items utilizing buffet warmers milk if you're not sure where it's from hamburgers not steaming hot fruits vegetables berries with intact skin sauces tap water things rinsed with tap water Swiss charter tourists 97% made a food faux pas within 72 hours
When travelers with diarrhea should get prompt medical attention
Severe illness bloody stool dysentery
Typhoid Fever and Travel
Short-term travel has risks -37% of cases occur in travelers staying < 4 wks 6 countries account for 76% of cases -India, Pakistan, Mexico, Bangladesh, Philippines, Haiti Only 4% of travelers had received typhoid vaccine in the 5 yrs preceding
Routine pre-travel vaccines (ones that may need updating)
Tetanus/diptheria/pertussis Pneumococcal Influenza Polio Measles
Traveller's diarrhea
This is a big deal 10% persistent diarrhea 30% confined to bed 60% of travelers get TD 40% change their itinerary because of it 20% are bedridden for part of trip 10% post-infectious IBS
HAV vaccine administration
Well tolerated and safe -Inactivated virus -OK to co-administer with other vaccines -If start with one brand of vaccine, OK to finish with the other vaccine
low risk (2-4%) for TD
U.S., Canada, NW Europe, Australia, N Zealand
malaria pitfalls
front end: -No prophylaxis -Wrong prophylaxis -Didn't take prophylaxis -Didn't avoid mosquitoes Back end: -Delayed diagnosis -Delayed treatment **Undifferentiated fever in the traveler returning from a malarious region is malaria until proven otherwise whether or not prophylaxis was taken*
primaquine side effects
must be G6PD negative -use only with expert advice
malaria
nighttime mosquitoes
doxycycline side effects
photosensitivity
atovaquone/proguanil side effects
renal impairment
