14 - Travel Infections Flashcards
1
Q
Types of traveller’s diarrhea
A
- Mild = tolerable, not distressing, doesn’t interfere w/ planned activities
- Moderate = distressing or interferes w/ planned activities
- Severe = incapacitating or completely prevents planned activities; all dysentery is considered severe
2
Q
Transmission of TD
A
Contaminated food and/or water
3
Q
Cause of TD
A
- Bacteria are most common cause (enterotoxigenic E. coli, shigella spp., campylobacter spp., salmonella spp.)
- Shigella is more rare but need a very small amount to cause severe TD
- Viral pathogens are 2nd most common cause (norovirus, rotavirus, astrovirus)
- Giardia main protozoal pathogen
4
Q
Sx of bacterial or viral TD
A
- Sudden onset of bothersome sx
- Can range from mild cramps & urgent loose stools to severe abdominal pain, fever, vomiting, bloody diarrhea
- Vomiting may be more prominent w/ norovirus
5
Q
Duration of TD
A
- Untreated bacterial diarrhea usually lasts 3-7 days
- Viral lasts 2-3 days
6
Q
Which countries have intermediate and high risk of TD?
A
- Intermediate risk = eastern Europe, south Africa, some Caribbean islands
- High risk = most of Asia, middle east, Africa, Mexico, central & south America
7
Q
Pt-related risk factors for TD
A
- Young adults
- Very young at higher risk of severe and/or prolonged TD
- Highest risk = immunocompromised, gastric acid suppression, IBD
- More common in px from low risk countries travelling to moderate or high-risk countries
8
Q
Environment-related risk factors for TD
A
- Warmer climates where access to plumbing is low => higher stool contamination in environment
- Inadequate electrical capacity => poorly functioning refrigeration => unsafe food storage
- Lack of safe water
- No handwashing stations in food prep areas
9
Q
Higher-risk foods
A
- Raw or undercooked meats, fish, & shellfish
- Uncooked vegetables, unpasteurized milk, cheese, or fruit juices
- Raw fruits that aren’t peeled (ex: berries)
- Food & beverages from street vendors
- Tap water
10
Q
Non-pharms for TD prevention
A
- Handwashing (no evidence for reducing TD, but have evidence for preventing diarrhea)
- Alcohol-based hand sanitizer if water not available
11
Q
OTC options for TD prevention
A
- Bismuth subsalicylate (Pepto-Bismol) 524 mg QID
- Probiotics (harmless, but result are inconclusive)
- Dukoral (oral, inactivated TD & cholera vaccine) for > 2 y/o; effectiveness not demonstrated for TD
12
Q
When should antibiotics be used as prophylaxis for TD?
A
- Px at high-risk for serious infections or complications (ex: immunocompromised, diabetes, end-stage renal disease, severe IBS)
- Travelling for a short time who can’t tolerate any down time (ex: athletes, professionals)
13
Q
Antibiotics for TD prophylaxis
A
Cipro or levo 500 mg once daily
14
Q
Goals of tx for TD
A
- Prevent dehydration and replace fluids
- Decrease duration & severity of sx
- Minimize impact of travel
15
Q
Pharm agents (other than antibiotics) for TD tx
A
- Loperamide
- Sx relief; useful adjunct to antibiotics
- 4 mg stat then 2 mg after each loose stool (max 16 mg/day) for adults
- Bismuth subsalicylate (BSS) 524 mg q30min to max of 8 doses/day
16
Q
Antibiotic for TD tx
A
- If prophylaxis used, then different antibiotic is used for tx
- Cipro 500 mg BID x 3 days or 750 mg x 1 dose
OR - Levo 500 mg once daily x 3 days or 1 g x 1 dose are 1st line
- Azithro may be preferred in certain px (allergies, pregnancy, children, breastfeeding) & regions b/c of resistance
– 500 mg once daily x 3 days or 1 g x 1 dose
– 5-10 mg/kg (max 500 mg) once daily x 3 days for children
17
Q
Guidelines for TD tx
A
- Mild = antibiotics not recommended; loperamide or BSS may be considered
- Moderate = antibiotics (FQs, azithro) may be used; loperamide may be used as adjunctive therapy for moderate-severe or monotherapy in moderate TD
- Severe = antibiotics should be used (azithro preferred); single dose antibiotic regimens may be used
- Good idea to give antibiotics to a backpacker who is more than 24 h away from medical care so that they can self-tx before they can get to medical care
18
Q
Malaria cause, sx, & transmission
A
- Human disease caused by 5 protozoan parasites
- Sx = fever & flu-like sx (chills, headache, myalgias, malaise); sx can occur at intervals
- Transmitted through bite of infected mosquito; rarely through blood transfusion, organ transplant, needle sharing, or congenitally from mother to fetus
19
Q
Malaria individual risk assessment
A
- A = awareness (where it occurs in the world)
- B = bite avoidance (sleep in screened accommodations; wear light, long clothing; tuck pants into socks; hours of biting between sunset & sunrise; use DEET 20% or more or icaridin 20% or more)
- C = chemo prophylaxis (see anti-malaria medications)
- D = diagnosis (any pt w/ history of travel to malaria areas should go to emergency to rule out malaria)
20
Q
Which cause of malaria is most likely to progress to severe infection?
A
P. falciparum
21
Q
Hepatitis A vaccine indications
A
- All susceptible people > 1 y/o should be vaccinated prior to departure to areas w/ high or intermediate hep A endemicity
- Intermediate risk = Mexico, some Caribbean, Central America, South America, North Africa, Middle East
- High risk = Africa (except North), India, Afghanistan, Pakistan, Bangladesh
22
Q
Hepatitis A vaccine dosing schedules
A
- Single dose gives protective antibody levels w/in 2-4 weeks, but is indicated regardless of time period before departure
- Full series includes 2 doses ranging from 6-36 months apart (recommended between 6-12 months apart)
23
Q
Hepatitis B vaccine indications
A
- All travellers to high and intermediate risk areas
- Causes of reduced immune response to hep B vaccine = older age, male, obesity, smoking, route of administration, some chronic underlying diseases
24
Q
Hepatitis B vaccine dosing schedules
A
- Conventional schedule at 0, 1, and 6 months gives optimal protection by month 7
- Accelerated schedule = 0, 7, and 21 days then 12 months after first dose
25
Q
Indication for combined hep A & hep B vaccine
A
Non-immune travellers > 1 y/o
26
Q
Dosing schedule for combined hep A & hep B vaccine
A
- Primary schedule = 0, 1, and 6 months
- 2 doses protect 100% against hep A but only 50-95% against hep B
- Single dose doesn’t provide adequate protection against HAV or HBV
- Accelerated schedule = 0, 7, and 21 days plus 12 months after first dose
