TRAVEL MEDICINE EVALUATION OF FEVER AND MEDICAL EMERGENCIES IN THE RETURNING TRAVELER
Outline of Travel Medicine Issues • Evaluation of Fever in the Returning Traveler • Medical Emergencies in Travelers • Traveler’s Diarrhea • Prevention of Infection: Vaccines and Antibiotic Prophylaxis • Geographic Infections : Abroad and at Home
Overview of Travel Related Illness • 20 to 70 % of 50 million travelers to the developing world report illness associated with travel. • 1 to 5 % end up seeking medical care • 1 in 100,000 dies of a travel related illness
Evaluation of Fever in the Returning Traveler • Careful documentation regarding • Time of onset of symptoms • Travel locales and accommodations • Activities and exposures • Host factors – medical /immune status
Evaluation of Fever – Time Factor • Timing of exposures –a powerful tool • Calculation of incubation periods • Duration of total travel- probability of an infection increases with stay( ie. relative risk of malaria is 80 fold for stays of >6 mos compared to a week) • Short-term travel rarely leads to helminthic infections; seen more commonly in immigrants • Fevers due to infection occurring more than one year after travel is distinctly uncommon.
Less than 2 weeks Malaria Ricketsiae Dengue Typhoid Diarrheal illnesses. 6 weeks or moreMalaria TB Hepatitis B Leishmaniasis Rabies Two – Six weeks Malaria Hepatitis A, E Leptospirosis Amebic abscess Schistosomiasis Incubation Periods
Evaluation of Fever:Prophylaxis History • Detailed vaccine/prophylaxis history- This does not exclude certain illnesses (ie: efficacy of yellow fever vaccine is greater than typhoid vaccine) • Malarial prophylaxis regimen may fail based on resistance patterns and patient compliance
Evaluation of Fever:Exposures • Food and Beverage Intake • Arthropod and Animal contacts • Recreational Activities- Hiking, Water exposures –fresh and salt water • Sexual contacts
Evaluation of Fever - Workup • Physical exam should carefully focus on: Skin for lesions, rash, genital lesions Lymph node, spleen and liver enlargement • Laboratory Tests: CBC with diff., LFT’s, Blood cultures, CXR and malarial smears x 3 Stool studies if symptomatic- O&P, cultures for enteric pathogens (SSCY) Serology if indicated by LFT’s (Hepatitis A,B,E, or E.Histolytica).
Fever and Eosinophilia • Peripheral eosinophilia is associated with helminthic infections that migrate through tissues - rarely with luminal infections • Acute Schistosomiasis • Acute Trichinosis • Acute Strongyloides • Lymphatic Filariasis
Evaluation of FeverEmergencies • Hemorrhagic Fevers Meningococcus Rickettsiae Leptospirosis Plague- Yersinia *Dengue Other viral hemorrhagic fevers (Lassa, Rift Valley, Congo-Crimean)
Hemorrhagic Fevers:Dengue Fever • Endemic in Caribbean, Central and South America and South Asia • Estimated 100 million cases/yr, with symptoms ranging from mild fever to shock and death. • Four distinct serotype (1-4) of this flavivirus, transmitted by mosquito • Prior exposure increases risk of DHF-shock
Dengue:Clinical Picture • Incubation period of 3-10 days • Fever, retro-orbital headache, myalgias-arthralgias –”break-bone fever” • Rash occurs 2- 5 days post fever onset,seen in 50% • GI symptoms in about 50% • Thrombocytopenia, leukopenia - 16-55% • Hemorrhagic Fever- seen with vascular leak and shock state • Serologic studies • Treatment is supportive only
Evaluation of Fever Emergencies Fever and Confusion and lethargy P.falciparum malaria (cerebral form) N.meningococcus Rickettsiae – R. conori, proweseki
Malaria • Fever in traveler from malarial region • Highest after rainy season; uncommon at altitude >2000 ft • Over 1,500 cases in US /yr • Appropriate prophylaxis is about 80% effective. • Incubation period varies by species- P.falciparum- 12-14 d P. vivax/ovale -up to 2 mos, can be years P.malariae- 35 days *P. knowlesi- transmitted in SE Asia; endemic in monkeys
Malaria:Evaluation and Rx • Fever associated with sweats, headache, myalgias. • Anemia, thrombocytopenia • Thick smears q 6-12 hours for 48 hrs. First smear + in 95%. • Parasitemia of greater than 3% should be hospitalized; greater than 5% have significant mortality when treated.
Malaria:Treatment For Chloroquine-sensitive species (P.vivax/ovale/malariae): • Chloroquine 600mg, followed by 300mg at 6, 24 , 48 hrs. For Chloroquine-Resistant P.falciparum Quinine+Doxycycline -7 days Malarone – 3 days (if no malarone prophylaxis) Mefloquine – 1250 mg in divided doses
Evaluation of Fever Emergencies • Respiratory Distress Malaria Hanta virus Influenza SARS Avian Influenza.
Travelers’ Diarrhea • Travel to the developing world carries a 40-60% risk of diarrhea- usually benign and self-limited. • More than 90% is bacterial, and food/water borne. • Most common pathogen – Enterotoxin E.coli (ETEC). • Parasitic enteritis requires a more contaminated environment than usually encountered by tourists. • Note: Airline food is prepared in departure city.
Travelers’ Diarrhea- Risk Factors • Low Risk (<10%) – N.Europe,Australia, US, Canada-but note high Giardia risk in US West/NE mountains • Moderate Risk (up to 20%) – Caribbean, Mediterranean, and Israel • High Risk (>30%) – Asia, Africa, Mexico, Central and South America • Gastric bypass and resection, histamine blockers will allow bacteria to survive to small bowel.
Travelers’ Diarrhea: Clues to Pathogens • Watery and Afebrile Most common pathogen is ETEC- the prototype travelers’ diarrhea is self limited • Bloody Diarrhea with Fever Salmonella, Shigella, Campylobacter and Yersina are invasive; E.histolytica. • Vibrio cholerae will cause a profound secretory diarrhea (“rice water”), with highest risk of dehydration/death.
Travelers’ Diarrhea: Therapy • Prevention: prophylactic antibiotics are not recommended unless a person’s medical condition or dehydration risk is severe- IBD Renal Immunosuppresion AIDS • Empiric Abx- quinolones; for convenience, consider qd dosing with levofloxacin indicated in cases of fever, blood or pus, and > 4 daily stools.
Skin Lesions in Travelers • Arthopod Bites- Myiasis -botfly larvae will penetrate skin and mature leading to a nodule. Tungiasis (sand flea larvae are expelled under skin after a blood meal). Rickestiae will see a necrotic ulcer
Skin Ulcers Tularemia Atypical Mycobacterial Endemic fungal STD’s –genital ulcers- Syphilis, LGV,Chanchroid Creeping Eruptions Cutaneous larva migrans (hookworm larva) Loiasis Strongyloidiasis. Skin Lesions in Travelers
Preventable Traveler’s Infections • Yellow Fever – viral, mosquito-borne,lethal • Malaria – parasitic, mosquito-borne, lethal • Typhoid Fever –bacterial, food-borne,contagious • Hepatitis A – viral, food-borne, contagious • Meningococcus – bacterial, contagious, lethal, seasonal and epidemic. • Japanese Encephalitis- viral, mosquito-borne, seasonal, lethal, low-risk for short-term travelers
Yellow Fever Prevention • An Equatorial infection in both East/West • A live-virus vaccine • Only vaccination legally required by certain countries for entry. • Four reported cases of vaccine-related multi-organ failure, with three deaths in 1996-98 in USA. • Contraindicated for pregnant and immunodeficient persons (live-virus). • Single IM dose; booster every ten years
Malaria Prevention • Nearly 300 million cases worldwide each year, with more than one million deaths. • Four species: Plasmodium falciparum, vivax, ovale and malariae. Fatalities with falciparum. • Several hundred cases/year in US travelers. During 1980-93, 3005 US cases with 51 deaths (1.7%). • Highest risk occurs in Sub-Saharan Africa. • Need to consider up-to-date resistance patterns.
Malarial Prevention • Prophylactic antibiotics are 90-95% effective. • Regimens routinely require starting pills 1-2 weeks prior to, and for 4 weeks following exposure. • Chloroquine is the first-line agent for travel to areas that still have chloroquine-sensitive P.falciparum, restricted to Central America, Middle East. • Chloroquine resistant strains of P.vivax have now appeared in Africa and Asia
Malaria Prevention • Topical insect repellants which include (DEET). Can see dermatitis, and neurotoxicity from absorption (caution with children-use lower %) • Mosquito netting sprayed with permethrin. • Note: Yellow Fever is transmitted by mosquitos that bite during daytime, malaria transmitted at night. • PREGNANCY- Chloroquine is safe, Mefloquine appears safe, Malarone data is still insufficient.
Malaria Prevention for Travel to Chloroquine Resistant (CR)Regions • Mefloquine- 250 mg q week (-1 to 4+ travel) active against all species, yet resistant strains of P.falciparum now exist in Africa and in Thai-Cambodian-Myanmar regions. Side effects include neuropsychiatric and GI. • Malarone– combination of atovaquone/proguanil. Taken qd 1-2 days prior to,during, and one week post. Equivalent to mefloquine vs. CR P.falciparum. • Doxycycline- 100 mg qd 1-2 days prior, 4 wks. post travel. Issue of photosensitivity.
Typhoid Fever and Prevention • Salmonella typhi is still prevalent in Asia, Africa and Latin America. • Risk appears greatest in Indian subcontinent. • Vaccination is best advised for those going to more remote regions, or during reported outbreaks • Oral vaccine(Vivotif)- taken prior to travel qod x 4, and can be boosted every 5 years. • Injectable(Typhim)- provides protection for 1-2 yrs • Both vaccinations provide about 50-80% protection
Homeland Security - Travel Medicine in the USA • Endemic infections must be considered in evaluation of fever after US travel. • Recreational activities increase the chance of exposure to arthropods and the endemic fungi • Ticks – Babesios (New England coast/islands) Lyme (Northeast coast, WI,CA) RMSF (Appalachia, Northeast) Erhlichiosis (Northeast, MO, AR) Tick Paralysis ( Rocky Mts.)
US Travel Medicine • Endemic Mycoses – Pulmonary/Systemic Blastomycosis – LA, WI, Miss. River valley Histoplasmosis – Ohio, St.Lawrence and Mississippi river valleys Coccidiomycosis - desert SW, San Joaquin • Hanta Virus Pulmonary Syndrome- NM,CO,AZ • Plague- flea bite, AZ bubonic not pneumonic
Prevention of Infections Related to Travel – Abroad and At Home • Potential exposures should signal a series of immunizations and prophylaxis. • Resources: • WWW. ISTM.org. • WWW. Cdc.gov • WWW. Tropnet.net • Travel Medicine Clinics
Be Careful Out There BON VOYAGE