II. Epidemiology
- Of those travelers returning with acute life-threatening illness, 9!% present with fever
- Up to two thirds of international travelers develop a travel related illness
- Most illnesses are minor and self-limited
- Most common travel related illnesses are Traveler's Diarrhea and respiratory infections (e.g. Influenza)
- However more than 50% seek medical advice prior to travel, and may lack recommended Vaccines and chemoprophylaxis
III. Indications
- Recent travel in the last 3-4 weeks
IV. Risk Factors
- Longer trips
- Lack of Pretravel Consultation (esp. lack of travel Vaccination, Malaria Chemoprophylaxis)
- Underlying comorbidity
- Pregnant women and children
- Travel to rural regions
- Outdoor activities (e.g. hiking, water activities)
- Visit to friends and relatives
- Typically stay longer in more remote or rural areas, with greater exposure to local food and drink
- Frequently avoid pretravel medical Consultation, Immunizations, chemoprophylaxis, and overall travel prevention
V. Precautions: Malaria and Other Important Infections
-
Fever in a returning traveler from Malaria endemic area is Falciparum Malaria until proven otherwise
- Stat blood smear with direct communication with reading pathologist
- Especially consider Malaria with Leukopenia and Left Shift, Thrombocytopenia
- Up to 50% of Malaria cases are misdiagnosed on the first visit
- Initial presentations are often mild and non-specific (fever, chills, malaise, myalgia, Headache)
- This is an emergent evaluation
- Other common causes in the differential of Malaria
- Other important travel-related infectious disease to consider
- Leptospirosis
- Trypanosomiasis
- Schistosomiasis
- Rickettsial Disease (e.g. Typhus, Rocky Mountain Spotted Fever and other Tick Borne Illness)
- Ebola
- Vaccine preventable illness that are more common outside the United States
- Consider Bacterial infectious conditions unrelated to travel
VI. Causes: Fever with other organ involvement
VII. Causes: By frequency in febrile travelers returning to developed countries
- Malaria (21%)
- Febrile Diarrhea (15%)
- Febrile respiratory infections (14%)
- Dengue Fever (6%)
- Non-Diarrheal, febrile gastrointestinal illness (5%)
- Fever with rash (4%)
- Genitourinary infections with fever (4%)
- Ricckettsia (2%)
- Typhoid Fever or Paratyphoid Fever (2%)
- Wilson (2007) Clin Infect Dis 44(12): 1560-8 [PubMed]
VIII. Causes: Geographic regions
- Caribbean
- Central America and South America
- South Central Asia
- Malaria (typically NOT Plasmodium Falciparum)
- Dengue Fever
- Enteric Fever (Salmonella typhi and paratyphi)
- Severe Acute Respiratory Syndrome (SARS)
- Chikungunya virus
- Southeast Asia
- Sub-Saharan Africa
- Malaria (mostly Plasmodium Falciparum)
- Tick-borne Rickettsiae (most common fever cause in southern africa)
- Acute Schistosomiasis
- Dengue Fever
- Chikungunya virus
- Filariasis
- Yellow Fever
- Leishmaniasis
- Hemorrhagic fever
- African trypanosomiasis
- Enteric Fever
- Katayama Fever
- Meningococcal Meningitis
- West Africa (Liberia, Sierra Leone, Guinea)
- Ebola (as of 2014)
- Worldwide conditions
- Human Immundeficiency Virus (HIV)
- Hepatitis A (common) , Hepatitis E, and other Viral Hepatitis
- Malaria
- Tuberculosis
- COVID-19
- References
- See CDC Yellow Book resource below
IX. Causes: Vector Exposures
- See Vector Borne Disease
- Mosquitoes
- Ticks
- Rickettsioses
- Tularemia
- Babesiosis
- African Tick Bite fever
- Lyme Disease
- Q Fever (Coxiella Burnetii)
-
Fleas
- Murine Typhus
- Rickettsial infection
- Yersinia pestis
- Mites
- Reduviid Bugs
-
Flies
- African Trypanosomiasis (Tsetse Flies)
- Leishmaniasis (Sand Flies)
- Loiasis
- Onchocerciasis or River Blindness (Black Flies)
-
Lice
- Borrelia recurrentis
- Rickettsial infection
X. Causes: Animal Exposures
- See Pet-Borne Parasitic Zoonoses
- See Animal Bite
- See Marine Injury
-
General
- Rabies
- Q Fever
- Tularemia (esp. Rabbits)
- Brucellosis
- Echinococcosis
- Plague
- Tetanus
- Livestock
- Cats
- See Pet Borne Zoonoses
- See Cat Bite
- Bartonella Henselae
- Capnocytophaga canimorsus (life threatening in Asplenic patients)
- Pasteurella multiocida
- Toxoplasmosis
- Dogs
- See Pet Borne Zoonoses
- See Dog Bite
- Dog Bites in developing countries is the most common cause or Rabies worldwide
- Cutaneous Larva Migrans (common)
- Helminths (e.g. Anclyostoma, Echinococcus, Toxocara)
- Parasites (e.g. Giardia)
- Bacterial Infections (Pasteurella, Leptospirosis)
- Bats
- Rabies
- Viral Hemorrhagic Fever
- Nipah Virus
- Histoplasmosis
- Respiratory Virus (SARS, SARS-CoV2, MERS)
- Rodents (or their urine or droppings)
- Hantavirus
- Lassa Fever
- Leptospirosis
- Plague
- Rat Bite Fever
- Rickettsioses
- Primates
- Exotic Birds
XI. Causes: Exposure Related Febrile Illnesses
- Sexually Transmitted Disease
- Infected Person Contact
- Viral Hemorrhagic Fever
- Enteric Fever (Salmonella typhi and paratyphi)
- Meningococcal infection
- Tuberculosis
- Severe Acute Respiratory Syndrome
- Raw or undercooked meat or fish
- See Foodborne Illness
- Enteric Infections
- Cestodiasis
- Trichinosis
- Typhoid Fever
- Cholera
- Salmonellosis
- Untreated water or unpasteurized dairy products
- See Waterborne Illness
- Salmonellosis
- Shigellosis
- Hepatitis A
- Amebiasis
- Cholera
- Brucellosis (dairy exposure)
- Tuberculosis (dairy exposure)
- Freshwater Exposure
- Barefoot Exposure
- Infected soil exposure or cave exploring
XII. Causes: Incubation Periods
- Incubation <7-10 days
- Traveler's Diarrhea
- Dengue Fever (common)
- Yellow Fever
- Spotted Fever (Rickettsiae)
- Meningococcemia
- Chikungunya
- Zika Virus
- Severe Acute Respiratory Syndrome (SARS)
- Cuteneous Larva Migrans
- Plague
- Viral respiratory infections (Influenza, Covid19)
- Incubation 7-21 days
- Amebiasis
- Babesiosis
- Leptospirosis
- Viral Hemorrhagic Fevers (including Ebola)
- Japanese Encephalitis
- Plasmodium FalciparumMalaria (common)
- Enteric Fevers
- Typhoid Fever (common)
- Paratyphoid
- Typhus
- East African Trypanosomiasis
- Q Fever
- Incubation >21 days
- Human Immundeficiency Virus (HIV)
- Hepatitis A (common) , Hepatitis E, and other Viral Hepatitis
- Malaria (common, symptoms may be delayed months)
- Tuberculosis (common, symptoms may be delayed years)
- Amebic Liver Abscess
- West African Trypanosomiasis
- Borreliosis
- Brucellosis
- Plasmodium Vivax and Plasmodium OvaleMalaria
- Visceral Leishmaniasis
- Systemic Schistosomiasis (Katayama)
- Visceral Leishmaniasis
- Filariasis
- Rabies
- Months
XIII. History
- Travel itinerary (establish a travel and exposure timeline)
- Who did you see (family, wildlife, farm animals)?
- Where did you travel (what region and countries, what environments, what living conditions)?
- When did you travel and for how long?
- What did you do (wilderness travel, mission work, farm work, construction)?
- Did you seek medical care while traveling?
- Did you take locally prescribed or recommended medications or therapies?
- Exposures
- Insects (e.g. ticks, Mosquitos)
- Animal exposures (including farm animals)
- See Pet-Borne Infection
- See Animal Bite
- See Marine Injury
- Skin Trauma
- See Cellulitis for specific exposures
- Contagious contacts (in travel country or home country)
- Sexually Transmitted Infection risk or exposure while traveling
- Did you use barrier protection?
- Drug resistant gonorrhea Prevalence is increasing world-wide
- Food sources of infection
- Water sources of infection (ingestion, fresh water swimming)
- Adventure Tourism
- Weather extremes (e.g. Cold Weather Injury)
- Rural exposures (e.g. Waterborne Illness, Vector Borne Disease)
- Medical Tourism (travel for less expensive surgical or medical care)
- Bacterial Infections acquired in travel are multi-drug resistant in up to 30% of cases
- ESBL Infections (esp. E. coli) are most common (esp. north africa, and southeast and southern asia)
- Sridhar (2021) Curr Opin Infect Dis 34(5): 423-31 [PubMed]
- Humanitarian Travel (e.g. medical missions)
- Health care workers may be at particular risk of unique infections
- Mass Gatherings (e.g. wedding)
- Medications
- New medications (especially immune compromising medications)
- Medications purchased in local pharmacies while traveling
- Pretravel Immunizations (and other Immunization status)
- Pretravel Antibiotic prophylaxis (e.g. Mefloquine for Malaria Prophylaxis)
XIV. Symptoms: General
-
Fever Pattern and course
- See Fever
-
Cough and other Respiratory Symptoms
- Often due to common Upper Respiratory Infections
- Influenza or Pneumonia (Close contact with local population)
- Q Fever (Farm exposure to cattle, goats, sheep or unpasteurized milk)
- Legionellosis
- Leptospirosis
- Acute Schistosomiasis or Katayama Fever
- Associated with boating or swimming in sub-saharan africa or southeast asia
- Coronavirus
- Corona Virus 19 (SARS-CoV2, Covid19)
- Severe Acute Respiratory Syndrome (SARS)
- Middle East Respiratory Syndrome (MERS)
- Travel to arabian peninsula in last 14 days (or exposure to traveler)
- Rash
- See Febrile Traveler with Rash
- Dengue Fever
- Chikungunya
- Zika Virus
- Typhus
- Enteric Fever
- Meningococcus
- Mpox (Monkeypox)
- Rash is uncommon with Malaria
- Aside from Petechiae in severe Falciparum Malaria with DIC
- Most common causes
- Lymphadenopathy
- Myalgia
- Malaria (mild to moderate Muscle pain and tenderness)
- Dengue Fever (severe Muscle pain)
- Leptospirosis (severe tenderness)
- Typhus (severe tenderness)
XV. Symptoms: Gastrointestinal
- See Gastrointestinal Disease in Returning Traveler
-
Abdominal Pain
- Red flag findings include Jaundice, Hepatomegaly, Splenomegaly or bloody Diarrhea
- Rash, Abdominal Pain and fever seen in Viral Hemorrhagic Fever, Brucellosis, Enteric Fever
- Typhoid Fever (Enteric Fever) is among the most concerning causes of fever and Abdominal Pain
- Eosinophilia, respiratory symptoms, adominal pain and fever seen in Helminth infection (e.g. Hookworm)
-
Diarrhea
- See Traveler's Diarrhea
- See Acute Inflammatory Diarrhea (bloody Diarrhea, Dysentery)
- See Infectious Diarrhea Causes
- See Foodborne Disease
- See Waterborne Illness
- Most Diarrhea in the returning traveler is self-limited and rarely caused by Parasites or Helminths
- Most common Bacterial causes include E. coli (enterotoxigenic and enteroaggregative)
- Febrile Seizures and Diarrhea seen in Shigellosis
- Covid19 presents with Diarrhea in one third of patients (half have Nausea or Vomiting)
- Differential diagnosis includes Hepatitis A infection and Clostridioides difficile
- Jaundice
-
Hepatosplenomegaly
- Acute Hepatitis (including Viral Hepatitis)
- Malaria
- Leishmaniasis
- Amoebiasis with abscess (Entamoeba histolytica)
- Enteric Fever
- Brucellosis
- Schistosomiasis
XVI. Symptoms: Neurologic
-
Altered Mental Status
- Cerebral Malaria
- Viral Encephalitis
- Tick-borne Encephalitis (esp. Eastern European Outdoor Exposure)
- Bacterial Meningitis (esp. Sub-Saharan African Meningitis belt)
-
Febrile Seizures
- Shigellosis (Diarrheal illness)
- Japanese Encephalitis (Mosquito-Borne Illness in Southeast Asia, Western Pacific)
- Dengue Hemorrhagic Fever
- Cerebral Malaria
- Chronic Parasitic Infections cause Seizures (however these do not present in the short-term traveler)
XVII. Exam: Focal areas
-
Vital Signs
- See Pulse-Temperature Dissociation
- Pulse slower than normal for fever degree (pulse fails to increase with fever spike)
- Seen with Typhoid Fever, Rickettsial infection
- Eye Exam
- Lymph Node Exam
- Cardiopulmonary Exam
- Abdominal Exam
- Neurologic Exam
- Skin Exam
XVIII. Labs
-
Complete Blood Count (CBC) with differential
- Observe for Eosinophilia (non-specific)
- Manual differential (standard with Wright stain)
- Test Sensitivity for Malaria approaching that of thin smear (Giemsa stain)
- Serum Electrolytes with Glucose
- Renal Function tests including Blood Urea Nitrogen
- Liver Function Tests
- Urinalysis
- Urine Pregnancy Test (if indicated)
- Malaria thick and thin smears (Giemsa stain) x3, 12 hours apart
- Serologies as indicated
- Serum sample spun and saved for later Antibody titers
- Infectious disease panel (multiplex and biofilm PCR) as indicated for system involved
- Consider Dengue Fever IgM, IgG and virus detection
- Diagnose and start treatment based on clinical findings if suspected
- Use labs only for confirmation
- Cultures
-
Stool Testing (consider if Diarrhea)
- Stool Culture or NAAT testing (including Salmonella typhi)
- Stool Ova and Parasite studies
- Stool Occult Blood
-
Cerebrospinal Fluid Examination
- Indicated in Altered Mental Status and fever
- Exclude Meningitis and Encephalitis
XIX. Management
- Consider Infectious Disease Consultation
- CDC and local public health mandate reporting of many of the febrile infections in returning travelers
- Consider empiric Antibiotic coverage until diagnosis
- Example: Doxycycline 100 mg orally twice daily
XX. Prevention
- See Travel Preparation
- Two most important, common Vaccine preventable illnesses
XXI. Resources
- CDC Yellow Book
- CDC National Notifiable Diseases
- CDC Current Outbreak List
- GeoSentinel
- https://geosentinel.org/
- Collaboration between CDC and the International Society of Travel Medicine (ISTM)
- Worldwide infectious disease surveillance (requires subscription
- Among the first to widely report Covid19 epidemic onset in China, late 2019
XXII. References
- Anderson (2014) Crit Dec Emerg Med 28(7): 11-9
- Black, Martin, DeVos (2018) Crit Dec Emerg Med 32(8): 3-12
- Mason and Marsh in Herbert (2019) EM:Rap 19(5): 12-3
- Nordurft-Froman and DeVos (2022) Crit Dec Emerg Med 36(4): 4-15
- Walker (2001) HP Primary Care Medicine Lecture
- Feder (2013) Am Fam Physician 88(8): 524-30 [PubMed]
- Lo Re (2003) Am Fam Physician 68(7):1343-50 [PubMed]
- Rathjen (2023) Am Fam Physician 108(4): 396-403 [PubMed]
- Suh (1999) Med Clin North Am 83(4):997-1017 [PubMed]