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see also  http://www2.ncid.cdc.gov/travel/yb/utils/ybBrowseO.asp
Investigating the Returned Traveller (Full sheet)

INVESTIGATING THE RETURNED TRAVELLER  - Summary

Assess Risk

• Africa - schistosomiasis
• Africa, PNG, Solomon Islands, Vanuatu - Malaria
• Exposure risk - contaminated food & water, insect bites, sexual contacts
• Risk increases with length of stay, remote area travellers & Backpackers

Febrile Illness - refer immediately if unwell

1. Malaria until proven otherwise
2. Typhoid Fever & Dysentery
3. Viral Hepatitis ( A to E )
4. Dengue
5. Others: pneumonia, legionnaires, septicaemia (meningococcal, staph, strep, meliodosis)
   gonorrhoea, chlamydia, leptospirosis, Q fever, typhus, acute HIV.

Investigations:

• Thick and Thin Blood films 12 hrly x 3 - one negative blood film does not exclude malaria
• If thrombocytopaenia there is a high chance of malaria - refer immediately

Diarrhoeal Illness - (NB. could still be malaria)

• Bacterial - Enterotoxigenic E. coli (ETEC) account for >80% of cases, Less common - Campylobacter, Salmonella, Shigella, Yersinia, Aeromonas
  - Single Faeces M & C usually will detect these (Nb. ETEC not detected with routine culture)
  - Treat Norfloxacin 800mg stat then 400mg BD for 3 days or Azithromycin (To hospital if unwell)

• Parasites - Giardia most frequent (Treat with Tinidazole 2 g orally stat)
  Less common but important: - Entamoeba histolytica, Hookworm, Strongyloides, Schistosomiasis, Cryptosporidium, Clostridium difficile and Vibrio cholera (especially if watery diarrhoea).
  - Stools M & C x 3 (ask for microscopy for tropical parasites - should also include immunoassay for Giardia & Crytosporidium antigens)
  - Persisting diarrhoea: collection of faeces using preservative may detect D.fragilis parasite
  - FBE may show eosinophilia (NB. giardia, amoebae and helminths (tapeworms, adult ascaris) DO NOT cause eosinophilia.)
• Treatment
  consider empirical therapy according to exposure
  - mebendazole 100mg BD 3 days - roundworm.
  - praziquantel - schistosomiasis, fasciola (drug is easy and safe to use).
  - Albendazole,: - ascaris,hookworm, strongyloides (drug has high toxicity; therefore pursue diagnosis actively).
  - Ivermectim - onchocerciasis & strongyloides
  - Tinidazole 2g daily 3 days (amoebic dysentery) or metronidazole 400mg three times a day for 10 days. cure rate > 95%
    For cyst carriers add diloxanide furonate 500mg three times a day for 10 days after metronidazole.
  

Schistosomiasis - An increasing illness amongst travellers & often asymptomatic

• Geography: - North & Central Africa particularly Sub-Saharan Africa
  - Egypt & Gulf states (Saudia Arabia, Iran, Iraq, Syria, Turkey)
  - India, China, Indonesia, Philippines, Thailand, Cambodia, Laos, Japan
  - South America
• Symptoms: - Acute febrile illness (Katayama Fever) often with urticarial rash.
  - Cercarial Dermatitis ( a common self limiting illness with itchy papules lasting a few days - symptomatic treatment only is required.)
  - Chronic Fibro inflammatory disease occurs after many years if untreated.
• Investigations: - Serology for all returned travellers from Africa and other risk areas who swam, waded or walked in streams or lakes. Schistosoma eggs can be ingested via contaminated water.
  - Check for Eosinophilia.
  - Other tests include Faeces for eggs & Terminal urine x 3 for microscopy
  nb. Serolgy is often negative with the early Katamaya fever and eggs do not appear until weeks later.
• Consider Empirical treatment:
• Treatment: Praziquantel 40mg/kg/d for 3 days gives 95% cure rate with no relapses. Eosinophilia often takes 6 months to reduce and may actually rise soon after treatment.

Serological tests of value

• Schistosomiasis: early seroconversion within weeks but may be delayed for up to 3 months
  few false negatives after 3 months
  some false positives occur
• Amoebiasis: highly specific.
  sensitivity:- extra intestinal disease - 95%
  invasive intestinal disease - 85%
  asymptomatic carrier - 10%
• Strongyloides: sensitivity & specificity - 80-90%
  (in comparison, stool microscopy = 80% sensitive)
• Filariasis: up to 30% false positives
  low positive results difficult to interpret -Treat: diethyl carbamazine
• Hydatid: sensitivity:
  active liver cysts 90%
  dead/calcified cysts 50%
  specificity: - poor at low titre IHA
  good at high titre IHA
• HIV: most positive by 3 months
  if high risk check at 6 & 12 months

Information mostly taken from: "International Travel and Health" (WHO year book - internet only)
Australian Immunisation Handbook, 8th Edition - 9/2003 - Part1 - Part 2 & Part 3 (large pdf files)
Centre for Disease Control, USA -  www.cdc.gov/travel Travel Health Seminar Oct 96, June 97,Feb 98, March 99, May 2000, August 2002 & March 2005 - Victorian Medical Postgraduate Foundation.
Manual of Travel Medicine, Melbourne, Oct 2004. Updated 06/09/2006.  Additional references & disclaimer.