Ambulatory Conference: Travel Medicine Hollis Ray, MD June 6, 2011

Travel Clinic   Should be carried out by persons who have training in the field, particularly for travelers who have complex itineraries or special health needs   Primary care physicians and non- specialists should be able to advise travelers who are in good health and visiting low-risk destinations with standard planned activities.

Travel Clinic  Epidemiology, transmission and prevention of travel-associated infectious diseases  A complete understanding of vaccine indications and procedures  Prevention and management of non- infectious travel health risks  Recognition of major syndromes in returned travelers (e.g., fever, diarrhea, and rash)

Immunization   Update vaccines/boosters: tetanus, pertussis, diphtheria, Haemophilus influenzae type b, measles, mumps, rubella, varicella, Streptococcus pneumoniae, and influenza   Hepatitis A and B, poliomyelitis, and Neisseria meningitidis – –for travel as well as for routine health care.   Yellow fever vaccine: endemic zones (Africa and S. America) – –some countries may require as a condition for entry   Vaccines against Japanese encephalitis, rabies, tick-borne encephalitis and typhoid fever – –Administered based on a risk assessment – –Quadrivalent meningococcal vaccine is required by Saudi Arabia for religious pilgrims to Mecca for the Hajj or Umrah.

Most Common Diagnoses   Short Incubation Period (<2 weeks) – –Malaria – –Typhoid fever – –Dengue – –Rickettsial disease – –Hepatitis A   Long Incubation Period (>4 weeks) – –Malaria – –Tuberculosis

Malaria

Malaria   Largely preventable   Incubation period: 10 days to 1 year   Signs and symptoms: GI symptoms, cyclical fevers, anemia, splenomegaly   Diagnosis: thick and thin peripheral blood smear – –Thrombocytopenia without leukocytosis CDC Public Health Image Library

Infecting Organisms   Plasmodium falciparum: potentially fatal and considered an emergency – –Acquired in Africa = 3:1 likelihood – –95% have clinical onset within 2 months exposure – –Peripheral blood smear: parasitemia > 2%, only ring forms, banana-shaped gametocyte, erythrocytes of all sizes infected, erythrocytes contain no Schuffner granules   Other species: P. vivax, P. ovale, P. malariae, P. knowlesi – –fevers occurring at regular intervals of 48 to 72 hours

Severe Malaria  Cerebral malaria, with abnormal behavior, impairment of consciousness, seizures, coma, or other.  Severe anemia due to hemolysis  Hemoglobinuria  Pulmonary edema or ARDS, which may occur even after the parasite counts have decreased in response to treatment  Abnormalities in blood coagulation and thrombocytopenia  Shock

Treatment of Severe Malaria in the United States Artesunate for hospitalized patients with  Severe malaria disease  High levels of malaria parasites in the blood  Inability to take oral medications  Lack of timely access to intravenous quinidine  Quinidine intolerance or contraindications  Quinidine failure

Malaria Chemoprophylaxis Largely based on resistance patterns to chloroquine phosphate or hydroxychloroquine sulfate. (IDSA Travel Medicine Guidelines)

Typhoid Fever   Typically present 1-3 weeks after ingestion of food or water contaminated with Samonella enterica serotype typhi   Have visited Indian subcontinent, in the Philippines, or in Latin America   Fever and constitutional symptoms – –May have insidious onset – –Abdominal pain, cough, chills – –Diarrhea may eventually develop

Typhoid Fever   Diagnosis: identify organism in urine, blood, stool, or bone marrow   Vaccines partially effective   Treatment: 3 rd gen. cephalosporin, floroquinolone, or azithromycin – –Relapse: 2-3 weeks after treatment

Typhoid Rash

Dengue Fever   Primary vector: Aedes mosquito   Caused by one of four different serotypes of Flavivirus   Incubation period: 4-7 days   Fever, severe myalgias, retro-orbital pain   Leukopenia and thrombocytopenia   Dengue shock syndrome and dengue hemorrhagic fever: second infection with a different serotype

Dengue Fever   Diffuse erythema or nonspecific maculopapular or petechial rash   No specific treatment – –IV fluids   Primary preventive approach: mosquito repellent and screens (NEJM 2002)

Travelers Diarrhea

Travelers Diarrhea   Between 20%-50% international travelers – –Onset: usually first week of travel but may occur later   Most common agent: enterotoxigenic Escherichia coli (ETEC)   Primary source of infection: ingestion of fecally contaminated food or water.   Most important risk determinant: traveler's destination – –Latin America, Africa, the Middle East, and Asia – –High-risk: young adults, immunocompromised, pts with inflammatory-bowel disease, diabetes, and persons taking H-2 blockers or antacids.

Travelers Diarrhea   Prevention: food and liquid hygiene and provision for prompt self-treatment in the event of illness – –Hydration, loperamide (if no fever >38.5 degrees C & no gross blood or mucus in stool) – –Short course (1 dose to 3 days) of a fluoroquinolone, azithromycin or rifaximin   Usually resolves in 3-5 days   Antibiotic prophylaxis is not recommended for most travelers

Prolonged Diarrhea   Greater than 2 weeks   Less likely to isolate specific organism   More likely to be parasitic – –Giardia lamblia, Cryptosporidium parvum, Entamoeba histolytica, and Cyclospora cayetanensis most frequently identified – –detected in fewer than 1/3 travelers with chronic diarrhea and in only 1-5% travelers with acute diarrhea

Hepatitis A Virus   Transmitted through fecal contimination of food and drink   Treatment: supportive (no antivirals)   Vaccination – –Should be immunized at least 2-4 weeks prior to traveling – –Single dose: 100% protection by 4 wks – –2 nd dose administered 6 months later results in antibody titers likely to last many decades

Rickettsial Diseases   Tick transmitted, occur throughout the world, typically named for geographic region –African tick bite fever (sub- Saharan) –Meditterranean tick bite fever (N. Africa and Middle East) –Exception: RMSF African tick typhus (NEJM 2002)

Rickettsial Diseases   Headache, fever, myalgias and often a truncal maculopapular or vesicular rash   Clinical clue: eschar at site of bite   Treatment: doxycycline, self-limited

Fungal Infections   Coccidioidomycosis: Southwest US, Mexico, and parts of South America   Histoplasmosis: Ohio River valley, Mexico, Central America   Penicillium marneffei: Southeast Asia, parts of China, Hong Kong, and Taiwan – –Disseminated infection increasing in immunocompromised patients (AIDS)

Scabies   Due to Sarcoptes scabiei infection   Common in – –Developing world – –Adventurous backpackers   Sexually active travelers are those most commonly infected

(Foot of a person who had recently visited the Caribbean) (NEJM 2002)

Cutaneous Larva Migrans   Most frequent serpiginous lesion among travelers   Results from migration of animal hookworms (e.g., Ancylostoma braziliense and A. caninum) in superficial tissues   Usually acquired after direct skin contact with soil or sand contaminated with dog or cat feces   Lesions – –may initially be papular or vesicular – –Pruritic – –commonly found on the foot or buttock

QUESTIONS

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