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South Pacific Underwater Medicine Society (SPUMS) Journal Volume 33 No. 2 June 2003 SPUMS Annual Scientific Meeting 2002
Abstract
(Batchelor T. Post-travel illness. SPUMS J 2003; 33: 91-97)An estimated 50 million people travel from industrialised countries to less developed areas of the world annually. Between20% and 70% of these travellers will experience ill-health whilst abroad. Although most of these ailments are minor,between 1% and 5% of travellers will seek medical advice either whilst abroad or on their return home. Additionally, oneshould consider groups such as refugees and asylum seekers who will present to doctors in industrialised nations withdiseases endemic to their home countries. In travellers, the most common health problems are diarrhoea, respiratoryinfections and skin conditions, relatively minor complaints that can be easily managed at the primary care level. One tothree per cent of post-travel patients will be febrile and, if they have travelled to an area endemic for malaria, should beinvestigated as a matter of urgency to exclude potentially life-threatening P. falciparum infection. The range of possiblediagnoses in a post-travel patient is diverse and can be daunting. Taking a thorough travel and exposure history andconsidering incubation times can result in a more workable differential diagnosis.
Introduction
diseases. The world’s population is now incredibly mobile– at any time a patient may walk into our clinics or An estimated 50 million people travel from the emergency rooms having departed from any point on the industrialised world to the less developed world each year.
globe within the last 24 to 48 hours.
Between 20% and 70% of these travellers will developillness related to their travels.1 Whilst most of these ailments Epidemiology
are minor, 1–5% of travellers will seek medical advice fortheir travel-related illness either whilst abroad or on their Data are increasingly being collected to analyse the return home.2 Thus, it is to be expected that doctors in epidemiology of travellers’ illness. One American study Australia and NZ will frequently be consulted by patients conducted in a travel medicine clinic analysed data collected who have acquired illness whilst travelling.
from 780 individuals who had travelled to less developedcountries for a period of less than three months. Of this Post-travel patients are diverse, with each group having cohort, 64% reported illness during their travels, the most unique potential exposures. Apart from the leisure traveller, common complaints being diarrhoea (46%), respiratory one should consider special groups such as humanitarianworkers, missionaries, religous pilgrims, the military,international students, business people, long-termexpatriates and their families, adventure travellers, those travelling for sex and so on. It is not just travellers from ILLNESS IN A USA POST-TRAVEL CLINIC (ref 3)
the industrialised world to the less developed world whoshould be considered when looking at post-travel problems.
One should also consider those moving in the opposite direction; refugees, immigrants, asylum seekers and migrant workers may all present with illness endemic totheir home country.
As in all fields of medicine, a thorough history will providethe majority of the information required to produce a workable differential diagnosis. In the case of post-travel presentation this is arguably even more important thanusual, as the range of possible illness is so broad and diverse.
The recent outbreak of SARS has highlighted the role that international travel can play in the spread of emerging Diarrhoea Respiratory
South Pacific Underwater Medicine Society (SPUMS) Journal Volume 33 No. 2 June 2003 10 MOST FREQUENT DIAGNOSES AT CIWEC
THE MINIMUM REQUIREMENTS FOR A POST-
TRAVEL MEDICINE CENTER, KATHMANDU,
TRAVEL MEDICAL HISTORY
DIAGNOSIS
Skin condition (rash, infection, dermatitis) Specific exposures: unsafe sex, swimming in fresh water or consumption of certain foodstuffs Pre-travel vaccinations: date(s) of administration Anti-malaria prophylaxis and compliance with Animal bite/rabies post-exposure prophylaxis tract symptoms (26%) and skin problems (8%). Of the study fractures and lacerations (4%), followed by a variety of other group, 26% reported illness on their return home. Once again, the most common complaints were diarrhoea (13%),respiratory tract symptoms (10%) and skin problems (3%) Thus, it is apparent that the majority of post-travel patients will present with relatively minor complaints that can bedealt with easily at the primary-care level. The febrile post- Similar figures are reported from the CIWEC Travel travel patient has more potential to be a medical emergency, Medicine Center in Kathmandu, Nepal (P. Pandey, personal but accounts for only 2–3% of ill travellers. Life-threatening communication). This Western-run travellers’ clinic sees conditions such as Plasmodium falciparum malaria must approximately 6,000 patients annually and collects data be excluded in these patients as a matter of urgency. An on all patient visits. These unique data provide an excellent analysis of 232 febrile post-travel patients admitted to the insight into the health problems of travellers whilst in a Royal Melbourne Hospital showed malaria to be the most destination country. Of 8,900 travellers analysed, the most common diagnosis (27%), followed closely by respiratory common complaints were acute bacterial diarrhoea (19%), tract infections (24%), then gastroenteritis (14%), dengue acute respiratory infection (14%), skin conditions (5%), fever (8%), enteric fever (3%) and a variety of other parasitic diarrhoea (5%), and injuries such as sprains, FEBRILE POST-TRAVEL PATIENTS ADMITTED TO THE ROYAL MELBOURNE HOSPITAL (ref 4)
Diarrhoea iagnosis
Respiratory
Hepatitis A
South Pacific Underwater Medicine Society (SPUMS) Journal Volume 33 No. 2 June 2003 Taking a post-travel history
TYPICAL INCUBATION TIMES FOR SELECTED
TROPICAL DISEASES
Apart from the standard medical history, a travel history should be taken in as much detail as possible (Table 2). Ata minimum this should include departure and return dates, SHORT (<10 days)
all countries and regions visited, illnesses that occurred Arboviral e.g., Japanese b encephalitis, dengue fever, whilst abroad, medications taken abroad, illness amongst fellow travellers and specific exposures such as unsafe sex, swimming in fresh water or consumption of certain foodstuffs. Pre-travel vaccinations and their date of Haemorrhagic fevers e.g., Lassa, Marburg, Ebola administration should be reviewed, as should the appropriateness of anti-malaria prophylaxis and patient compliance with the prescribed regimen.
A detailed geographical history will help exclude many potential pathogens and may also provide very specific clues. Activities undertaken can also offer specific clues.
For instance, white-water rafting is associated with leptospirosis, walking safaris in southern Africa with African tick bite fever, and sexual contact with HIV. An Typhus – African tick bite, flea-borne, scrub, Rocky accurate timescale of potential exposures and knowledge of incubation times are essential as these parameters maybe used to exclude many aetiologies (Tables 3 and 4).
MEDIUM (10–21 days)
•
A thorough examination with a particular emphasis on Arboviral e.g., Murray Valley encephalitis, tick-borne temperature, lymphadenopathy, skin, chest, liver and spleen is imperative and may add further clues. Baseline Haemorrhagic fevers e.g., Congo-Crimean, Lassa, investigations for a febrile patient should include: full blood count (FBC), three malaria smears, antigen testing, liver function tests, urea, electrolytes, blood culture, urinalysis, chest X-ray, stool and serum for relevant serology.
Fever in the post-travel patient
Febrile travellers must be assessed with urgency, in particular to exclude potentially life-threatening P. falciparum malaria. The ‘big four’ illnesses to exclude in the febrile traveller are malaria, dengue fever, enteric fever and hepatitis. The list of potential diagnoses is extensive and will not be covered in this review. A recent review article by Schwartz provides a timely methodological approachfor the evaluation of fever in the returned traveller.5 LONG (>21 days)
•
Malaria has been covered in detail in a previous article in this series and will not be discussed again.6 It is, however, important to emphasise that malaria remains the most frequently diagnosed disease in the febrile traveller and may be rapidly fatal.4 The fever pattern in malaria is variable and may not be continuous, and the absence of fever at the time of evaluation should not exclude the possibility of malaria. At least three negative malaria smears read by a competent pathologist over a period of 48 hours are required to exclude the diagnosis. Most would agree that all patients with P. falciparum should be admitted to hospital fortreatment as their clinical status may deteriorate rapidly.
South Pacific Underwater Medicine Society (SPUMS) Journal Volume 33 No. 2 June 2003 SPECIFIC EXPOSURES FOR SELECTED
Dengue fever is increasingly being recognised as a risk to TRAVEL-RELATED DISEASES
travellers. Dengue viruses are the most common cause ofarboviral disease in the world and are estimated to cause50–100 million cases of dengue fever annually.7 Untreated water
Hepatitis A and E, bacterial diarrhoea, cholera The principal vector of dengue, Aedes aegypti, is found Unpasteurised dairy products
throughout the world between the latitudes of 35O North and South. It is a highly efficient vector and over the past Undercooked meat
60 years the incidence, distribution and clinical severity of Cestodes, trichinosis, bacterial diarrhoea dengue has increased dramatically.7 An analysis of European Animal contact/bites
travellers who had contracted dengue abroad showed that Rabies, Q fever, typhus, echinococcosis, leptospirosis over 50% of cases were acquired in Asia. Thailand and Mosquitoes
India in particular are high-risk destinations.8 Of patients Malaria, dengue fever, yellow fever, arboviruses admitted to the Royal Melbourne Hospital with dengue, Sand flies
Tsetse flies
Dengue has a short incubation period of four to seven days and in the classical presentation common symptoms include the abrupt onset of high fever, severe headache, retro-orbital pain, myalgias, arthralgias and sometimes a maculopapular rash. Laboratory findings commonly associated with dengue include neutropenia, lymphocytosis, and thrombo- Freshwater exposure
cytopenia.7 Diagnosis is by virus isolation or positive serology. There is no specific treatment available for dengue.
Barefoot exposure
Patients should be watched for signs of dengue Strongyloidiasis, cutaneous larva migrans haemorrhagic fever (DHF), the more severe manifestation Sexual contact
of the illness. DHF is primarily a disease of children under 15 in hyperendemic areas, characterised by haemorrhagic IV drug use/tattoos/transfusions
manifestations and a platelet count of less than 100,000.7 Sick contacts
Enteric fever is the clinical syndrome caused by Salmonellatyphi (typhoid fever) or ‘paratyphi’ Salmonella species(paratyphoid fever). The dominant symptoms are sustainedfever and headache. Patients have constipation, abdominal vaccine. It is therefore disturbing to see that hepatitis A pain, and a dry cough. Leukopenia and thrombocytopenia still accounted for 3% of the patients in the Royal Melbourne may be present on FBC. The most common destination for Hospital series. This reflects a failure of travellers to seek acquiring the illness is the Indian subcontinent (India and appropriate advice pre-travel, or of healthcare providers to Nepal), which now has increasing species of quinolone- offer adequate pre-travel vaccination advice.
resistant Salmonella. Eighty per cent of the cases of typhoidfever treated at the CIWEC Travel Medicine Center in Hepatitis E is endemic in Nepal and there is currently no Kathmandu, Nepal, this year have been resistant to vaccine available. Like hepatitis A, it is food and water ciprofloxacin (W. Cave, personal communication).
borne and presents clinically in a manner indistinguishable Interestingly, older drugs such as co-trimoxazole are being from hepatitis A. Hepatitis E is a particularly serious disease found to treat the illness successfully. Diagnosis is made in pregnant women resulting in a 30% maternal and fetal by culture. Blood culture is approximately 50% sensitive, mortality rate if contracted in the final trimester. A vaccine whilst bone marrow is more reliable and offers trial is currently underway in Kathmandu; unblinding of approximately 90% sensitivity. Without treatment, the case the results will occur in May of this year. Interestingly, this fatality rate of enteric fever is 10%. This is reduced to less study has been conducted in members of the Royal Nepalese than 1% with appropriate antibiotic therapy.
Army and has shown an incidence rate of 5% in the studypopulation (R. Scott, personal communication). The diagnosis is made on serology and should be considered inall cases of hepatitis in travellers, particularly in those to Theoretically, hepatitis A should no longer be a cause of the Indian subcontinent. Treatment is supportive.
fever in travellers since the advent of a highly effective South Pacific Underwater Medicine Society (SPUMS) Journal Volume 33 No. 2 June 2003 Diarrhoea
The laboratory should be specifically requested to look forCryptosporidium; at 4 microns (mm) diameter it is best Acute traveller’s diarrhoea has previously been discussed diagnosed using an acid fast stain and fluorescent in these review articles.9 Chronic diarrhoea (diarrhoea of microscope. In immunocompromised individuals, greater than two weeks’ duration) is more likely to present Cryptosporidium can be a debilitating illness and there is to the doctor evaluating a post-travel patient. Chronic currently no highly effective treatment.
diarrhoea is more commonly parasitic than bacterial inorigin, however a bacterial cause should always be excluded.
Cyclospora accounts for 5% of the diarrhoea seen in In Kathmandu, Campylobacter is the second most Kathmandu, a city known to be highly endemic for the commonly found pathogen in patients with diarrhoea lasting parasite. Cyclospora appears during the hot, rainy monsoon for two to four weeks (P. Pandey, personal communication).
months in Nepal (June to October) and is characterised by The most common parasitic causes of prolonged diarrhoea the abrupt onset of watery diarrhoea accompanied by upper in travellers are Giardia lamblia, Entamoeba histolytica, abdominal symptoms. Profound fatigue is commonly Cryptosporidium and Cyclospora.10 reported. The parasite is 8 mm in diameter and can beidentified by the naked eye by an experienced microscopist, but is more easily identified with acid fast staining. Onceagain, the laboratory should be specifically asked to look Giardia lamblia is the most common protozoan infection for Cyclospora. Treatment is with trimethoprim- in returning travellers.10 At the CIWEC clinic it accounts sulphamethoxazole double strength, twice daily for one for 5% of cases of traveller’s diarrhoea. G. lamblia tends to week. Unfortunately there is no alternative treatment for cause a prolonged, low-grade illness characterised by two those with sulphur allergy and without treatment the illness to five loose bowel motions daily with accompanying nausea, mild fatigue and abdominal discomfort.
‘Sulphurous burps’ are often mentioned in travel books as If travellers have been on antibiotics, the diagnosis of being specific to G. lamblia, however analysis of data Clostridium difficile should also be entertained and a request collected at CIWEC has shown that they are no more for C. difficile toxin made on stool examination.
common in patients with G. lamblia than those with anyother pathogen.
G. lamblia is diagnosed by stool examination, but may be Tropical sprue is a malabsorption syndrome acquired in difficult to find. Antigen testing can also be carried out and the tropics and associated with weight loss, fatigue and this gives a more reliable result. Empiric treatment for decreased appetite. The cause of the disease remains giardiasis is often suggested if a bacterial cause has been unclear; however, it often occurs after an episode of acute excluded in a patient with chronic diarrhoea post-travel.
bacterial diarrhoea when travelling. Diagnosis is made after Tinidazole, 2 g daily for two days, is the standard protocol.
empiric treatment for parasitic causes has failed, if the In some areas of the world e.g., Kathmandu, tinidazole clinical criteria are fulfilled and the patient has an abnormal resistance is now developing. Treatment with quinacrine, D-xylose test. Treatment is with 250–500 mg tetracycline 100 mg three times daily (TDS) for five days, is effective four times daily for four to six weeks, and folate 5 mg daily.
treatment in these refractory cases.
If there is no response after four weeks of treatment analternative diagnosis should be considered and the patient should be referred to a gastroenterologist.10 Entamoeba histolytica is an unusual cause of diarrhoea in Patients with chronic diarrhoea who do not respond to travellers. The most important point to raise regarding E. empiric treatment for bacteria and parasites, have a clear histolytica is the identification of two distinct but stool, no evidence of colitis, no weight loss and a normal morphologically identical strains of amoebae.11 E. D-xylose test are a problematic group. Dietary manipulation histolytica is a pathogen that can cause disease ranging may be helpful, for instance avoidance of dairy products. It from asymptomatic to liver abcess and fatal colitis. E. dispar is important that they are reassured they do not have a is non-pathogenic. The two strains are indistinguishable hidden parasite and do not waste their time doctor shopping under the microscope and can only be differentiated using in order to find a solution. Post-infectious irritable bowel E. histolytica antigen testing. E. dispar does not require syndrome (IBS) is the most likely diagnosis and should be treatment whereas E. histolytica should be treated with managed along standard lines for the treatment of IBS.
tinidazole 2 g daily for three days followed by diloxanidefuroate 500 mg TDS for 10 days.
One should also be aware of the possibility of inflammatorybowel disease presenting for the first time post-travel. Thus, if there is weight loss, evidence of colitis or any concerningclinical features the patient should be referred to a Cryptosporidiosis is also uncommon in travellers but should be considered in all cases of prolonged diarrhoea post-travel.
South Pacific Underwater Medicine Society (SPUMS) Journal Volume 33 No. 2 June 2003 Skin conditions
Treatment consists of removal of the larva by occludingthe punctum with vaseline or an occlusive dressing for 12 hours and then gentle removal. Antibiotics are not requiredunless there is evidence of secondary infection. Prevention Cutaneous larva migrans is the most commonly reported skin condition in travellers returning from tropicalcountries.12 It is caused by the larvae of animal hookworms In Africa, the tumbu fly will present in a similar fashion.
Ancylostoma braziliense or A. caninum. Humans are However, the eggs of the fly are usually laid on people’s infected as a result of skin contact with contaminated soil.
clothes as they are hung out to dry. When the infected clothes Humans are only an incidental host, however, so whilst the are worn the eggs hatch and penetrate the skin, and multiple larva burrows through intact skin it remains in the upper lesions are the norm. Prevention is by ironing all clothes dermis.13 Time from exposure to the onset of symptoms is one to six days and classically the lesion will start as anerythematous papule that then becomes serpiginous as the Other common skin conditions include pyoderma, insect larva burrows along the upper dermis. It is usually intensely bite dermatitis, tungiasis and urticaria.
pruritic and it is this symptom that causes people to seektreatment. Complications such as impetigo and allergic Schistosomiasis
reactions may occur. Whilst it is a self-limiting condition(spontaneous healing usually occurs within weeks or Special mention should be made of schistosomiasis as it is months), treatment with ivermectin or albendazole will common for travellers to present to their primary-care doctor usually result in rapid resolution of troublesome symptoms.14 requesting that they be checked for infection after travel toan endemic area. Schistosomiasis is caused by various species of blood flukes belonging to the genusSchistosoma.19 The majority of infected travellers will be Leishmaniasis results from infection with one of the exposed to schistosomiasis in Africa, particularly by protozoan parasites of the Leishmania species. The swimming in freshwater lakes such as Lake Malawi. There organism is transmitted to humans by the bite of an infected are four species of schistosomes that infect man but they sandfly and occurs in tropical and subtropical areas all have the same lifecycle. Eggs are voided from humans throughout the world except Australia. Worldwide, over in their stool and urine. On reaching fresh water, these two million cases occur each year and leishmaniasis is eggs hatch and their larvae then infect specific species of increasingly recognised as a risk to travellers.15 The majority aquatic snail (the intermediate host). After a period of time, of cases in travellers are contracted in central and South the microscopic larvae are released into the water. Humans America.16 There are three quite distinct clinical syndromes then become infected by exposure to the fresh water.
– visceral leishmaniasis, cutaneous leishmaniasis andmucocutaneous leishmaniasis. The majority of cases in If patients are symptomatic, they will most commonly travellers are of cutaneous leishmaniasis. An ulcerous skin present with haematuria, dysuria or urinary frequency if lesion develops at the site of the bite. These lesions are infected with S. haematobium, or with abdominal pain, typically painless and slowly progressive and will heal diarrhoea and rectal bleeding if infected with S. mansoni.20 spontaneously after between three and six months.17 The majority of infected individuals are, however, Diagnosis is made by biopsy and the patient should be asymptomatic and present for screening as they are aware referred to an infectious diseases specialist.
that they may have been exposed. As infection can result indelayed serious complications, all travellers requesting investigation should undertake the following, ideally at least12 weeks after their final exposure: FBC, schistosomiasis Myiasis is caused by the invasion of skin by larval maggots serology, one stool sample and urine dipstick. Eosinophilia of various Diptera fly species – most commonly the botfly is not a reliable finding. Serology is far more reliable with in South America and the tumbu fly in Africa.17 The botfly the ELISA test being >95% sensitive for S. mansoni and is the common name for Dermatobia hominis. The botfly 90% sensitive for S. haematobium. Stool and urine lays its eggs on another insect, usually a mosquito, which microscopy provides additional support for a positive then transfers the eggs onto human skin whilst feeding.
serological result. However, most travellers have a low These eggs penetrate the skin and then slowly develop into parasite burden and hence rarely show eggs on microscopy.
larvae, thus creating a subcutaneous nodule. At this stage, Positive serology requires treatment with praziquantel 20 the larva remains in contact with the air and thus there is a punctum in the nodule through which the larva breathes.18Afflicted patients often feel a sensation of movement within Investigating the asymptomatic post-travel patient
the nodule as the larva grows. After about four to six weeksthe larva matures and emerges from the lesion; however, Travellers will often present requesting a ‘post-travel most people seek medical attention before this occurs.
checkup’. A thorough history should be taken that looks South Pacific Underwater Medicine Society (SPUMS) Journal Volume 33 No. 2 June 2003 for particular exposure risks, especially sexually transmitted 15 Roberts LJ, Handman E, Foote SJ. Science, medicine diseases and schistosomiasis. A thorough examination and the future: Leishmaniasis. BMJ 2000; 321: 801- should also be performed. A basic work up would include a FBC, one stool sample for ova/cysts/parasites (O/C/P) and 16 Herwaldt BL, Stokes SL, Juranek DD. American serology as relevant e.g., for schistosomiasis or an STD cutaneous leishmaniasis in U.S. travelers. Ann Intern checkup. This is a good opportunity to offer any vaccine boosters that may be required, or to undertake a post-travel 17 Kain KC. Skin lesions in returned travelers. Med Clin Mantoux test if required. One should also keep in mind psychological problems that may occur after travel. In 18 Rubel DM, Walder BK, Jopp-McKay A, Rosen R.
particular, readjustment disorder (reverse culture shock) Dermal myiasis in an Australian traveller. Australas J for long-term travellers and expatriates is a well-recognised phenomenon and may present with somatisation.
19 Joubert JJ, Evans AC, Schutte CH. Schistosomiasis in Africa and international travel. J Travel Med 2001; 8: References
20 Day JH, Grant AD, Doherty JF, Chiodini PL, Wright Ryan ET, Wilson ME, Kain KC. Illness after SG. Schistosomiasis in travellers returning from sub- international travel. N Eng J Med 2002; 347: 505-516 Saharan Africa. BMJ 1996; 313: 268-269 Steffen R, Rickenbach M, Wilhelm U, Helminger A,Schar M. Health problems after travel to developing Dr Trish Batchelor, MB, BS, FRACGP, MPH (Trop Med), countries. J Infect Dis 1987; 156: 84-91 is the Medical Adviser to The Travel Doctor TMVC, New Hill DR. Health problems in a large cohort of Americans Zealand. Trish was the principal guest speaker at the traveling to developing countries. J Travel Med 2000; SPUMS ASM, Port Vila, Vanuatu, May 2002. O’Brien D, Tobin S, Brown GV, Torresi J. Fever in Currently she is working as a medical officer at the CIWEC returned travelers: review of hospital admissions for a Travel Medicine Centre, PO Box 12895, Durbar Marg, 3-year period. Clin Infect Dis 2001; 33: 603-609 Schwartz MD. Fever in the returning traveler, part one: E-mail: <[email protected]>
a methodological approach to initial evaluation.
Wilderness Environ Med 2003; 14: 24-32 Batchelor T. Malaria and the traveller. SPUMS J 2003;33: 11-18 Gibbons RV, Vaughn DW. Dengue: an escalatingproblem. BMJ 2002; 324: 1563-1566 Jelinek T, Muhlberger N, Harms G, et al. Epidemiologyand clinical features of imported dengue fever inEurope: sentinel surveillance data from TropNetEurop.
Clin Infect Dis 2002; 35: 1047-1052 Batchelor T. Traveller’s diarrhoea. SPUMS J 2002; 32: 10 Taylor DN, Connor BA, Shlim DR. Chronic diarrhoea in the returned traveler. Med Clin North Am 1999; 83:1033-1052 11 Jackson TF. Entamoeba histolytica and Entamoeba dispar are distinct species; clinical, epidemiologicaland serological evidence. Int J Parasitol 1998; 28: 181-186 12 Caumes E, Carriere J, Guermonprez G, Briacaire F, Danis M, Gentilini M. Dermatoses associated withtravel to tropical countries: a prospective study of the diagnosis and management of 269 patients presentingto a tropical disease unit. Clin Infect Dis 1995; 20:542-548 13 Caumes E. Treatment of cutaneous larva migrans. Clin 14 Bouchaud O, Houze S, Schiemann R, et al. Cutaneous larva migrans in travelers: a prospective study, withassessment of therapy with ivermectin. Clin Infect Dis2000; 31: 493-498

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