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Canada Communicable Disease Report
Volume: 23 (ACS-1)
1 April 1997
An Advisory Committee Statement (ACS)
Committee to Advise on Tropical Medicine and Travel (CATMAT)
FEVER IN THE INTERNATIONAL TRAVELLER INITIAL ASSESSMENT
GUIDELINES
Introduction
1. Initial approach to the diagnosis in the acutely
febrile, returning traveller
2. Public-health and quarantine services, and documents
related tonternational disease control
Appendix
References
Introduction
Fever is a cardinal sign of disease (1,2) , but it is sufficiently
non-specific to be of little etiologic or diagnostic assistance on its
own. A detailed history, including a complete travel history, and an appropriate
physical examination are essential starting points. The judicious use
of laboratory testing should follow. These steps are essential in defining
the cause of fever in international travellers. It must be emphasized
that diagnoses of the tropical causes of fever are likely to be missed,
with serious consequences to the patient, if febrile patients are not
asked about their travel exposures (3,4) . All febrile patients
must be asked if they have travelled. If exposed to malaria, they must
be assumed to have it, until proven otherwise.
This article addresses two features of fever in the international
traveller:
-
the initial approach to the diagnosis in the acutely febrile,
returning traveller; and
-
public-health and quarantine services, and documents related to
international disease control.
* Members: Dr. W. Bowie; Dr. L.S. Gagnon; Dr. S. Houston; Dr.
K. Kain; Dr. D. MacPherson (Chairman); Dr. V. Marchessault; Dr. H. Onyett;
Dr. R. Saginur; Dr. D. Scheifele (NACI); Dr. F. Stratton; Mrs. R. Wilson
(CUSO).
Ex-Officio Members: LCdr. D. Carpenter (DND); Dr. E. Gadd (HPB);
Dr. B. Gushulak (Secretary); Dr. H. Lobel (CDC); Dr. A McCarthy (LCDC
and DND); Dr. S. Mohanna (MSB); Dr. M. Tipple (CDC).
1. Initial approach to the diagnosis
in the acutely febrile, returning traveller
Although travel raises the possibility of an unusual imported disease
in the returning ill traveller, non-tropical diseases such as viral infections,
pneumonia, and urinary tract infections remain common. Table 1 presents
two lists of causes of fever in returning travellers as diagnosed by tropical
medicine clinics. It is important to note that malaria is by far the most
frequent tropical cause of fever, accounting for 30% to 40% of causes
of fever in returning travellers. Immediate diagnosis must be made and
immediate action taken to preserve the health of the individual as well
as to protect the community in cases of malaria, meningitis, and the viral
causes of hemorrhagic fever. The interested reader is directed to more
detailed discussions of the returning ill traveller for additional information
( 5-8) .
Table 1 Reported causes of fever in returning travellers
Diagnosis
|
Report 1 (31)
(n=587)
%
|
Report 2 (32)
(n=195)
%
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Malaria
Respiratory illness*
Diarrheal illness
Hepatitis
Dengue
Urinary tract infection
Enteric fevers
Tuberculosis
Meningitis
Acute HIV infection
Miscellaneous
Undiagnosed
|
32
11
4.5
6
2
4
2
1
1
0.3
11.3
25
|
42
2.5
6.5
3
6
2.5
2
2
1
1
8
24.5
|
*includes upper respiratory infections, bronchitis, and pneumonia.
|
The approach to fever in the traveller must begin with a detailed travel
history, which includes departure and arrival dates, countries visited,
nature of exposure abroad, pre-exposure vaccinations, and the use of antimalarial
drugs and other antimicrobials. A knowledge of incubation periods, and
global distribution and mode of transmission of tropical diseases will
assist in forming a differential diagnosis. There are several published
resources which detail the global distribution of diseases (9-11)
. In addition, there are frequently updated epidemiologic reports on specific
diseases, such as malaria (12-16) , polio(17-19)
, and tuberculosis (20-21) . Table 2 presents typical incubation
periods for common tropical diseases.
In a recent prospective survey of fever in 1,572 volunteer travellers,
123 of 1,187 (10.4%) travellers who returned their surveys reported having
had fever (22) . In the majority of patients, malaria was not
considered as a possible diagnosis by travellers themselves. Only six
of these 123 travellers treated themselves for presumptive malaria. An
extensive evaluation of the cause of fever in these six travellers resulted
in the following diagnoses: three viral infections (one dengue), one gastritis,
one amebiasis, and one malaria (species not stated). An additional 14.2%
of travellers were ill or had an accident, but had no fever. The remaining
73.5% reported no illness at all during their travels or during the 1
month following return. Fevers are common in travellers but are rarely
acted upon as potentially serious illnesses. Improved pre-travel counselling
on the implications of fever during or following international travel
is needed to reduce delays in seeking medical assistance and to increase
the awareness of tropical diseases in travellers.
Table 2 Incubation periods for selected tropical infections (33)
Infection
|
Incubation period
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Malaria
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P.falciparum
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7 days (minimum) to 12 weeks (usual maximum)
|
P.spp.
|
Weeks to several years
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Dengue
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3 to 14 days
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Hepatitis A
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15 to 50 days
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Hepatitis B
|
45 to 180 days
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Enteric fevers
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Typhoid
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3 days to 3 months (usually 1 to 3 weeks)
|
Campylobacte
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1 to 10 days (usually 2 to 5 days)
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Shigella
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12 to 96 hours
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Viral hemorrhagic fevers
|
2 to 21 days
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The physical examination must address two questions.
-
Is there an obvious source or cause for the fever?
-
Are there any manifestations of sepsis, shock or hemorrhage?
Clinical findings may assist in defining the most probable cause of fever
in the international traveller, although laboratory testing is usually
required to confirm the diagnosis. For example, the presence of a tick
eschar points to typhus, rose spots to typhoid fever, and jaundice to
hepatitis.
The initial laboratory investigations (Table 3) should be directed toward
the most probable cause of fever. Malaria films must be performed and
competently examined as a matter of urgency, if the patient has travelled
through a malarious zone. If blood films can not be examined quickly and
competently, the films or the patient should be referred as quickly as
possible to a centre where this can be done (23) . The urgency
in examining blood films is independent of whether the patient has used
antimalarial chemosuppressive therapy or not. The greatest risk period
for clinical presentation of Plasmodium falciparum infections is
in the 12 weeks following the last, potential, infected-mosquito exposure.
Blood films may need to be repeated even if the first ones are negative.
Table 3 List of initial laboratory investigations for fever in the
returning traveller
- Complete blood count, white cell differential, and platelet
count
- Thick and thin blood films for malaria parasites
- Blood cultures
- Liver transaminases and bilirubin
- Urine screening
- Chest x-ray (if clinically indicated)
- Save serum aliquot (held as "acute sera" for subsequent
serologic testing
|
Features of sepsis, shock or hemorrhage raise concerns of bacterial sepsis
(e.g. enteric fever, meningococcemia), severe and complicated malaria,
and viral hemorrhagic fevers (e.g. severe dengue, Ebola, Lassa, etc.).
Cultures of blood, urine, and possibly cerebral spinal fluid must be performed.
Presumptive therapy should be considered for severe or life-threatening
infections. If diagnostic or treatment difficulties arise, consultation
with an expert in tropical medicine or infectious diseases should be sought
as soon as possible.
Practice Point
Diagnosis must begin with a detailed travel history. The febrile traveller,
who was exposed to malaria, has malaria until proven otherwise.
Recommendation 1
All assessments of febrile patients should include a travel and exposure
history. Once a history of travel is obtained, a complete assessment of
its relevance to the febrile event is required.
Category A(24)
Good evidence to support a recommendation for use.
Grade III
Evidence from opinions of respected authorities on the basis of clinical
experience, descriptive studies, or reports of expert committees.
2. Public-health and quarantine
services, and documents related to international disease control
Local, provincial, and federal public-health and quarantine services
are responsible for surveillance, detection, and interventions to protect
Canadians against communicable diseases. Recent events, such as international
outbreaks of plague in India (25) , Ebola virus in Zaire (26)
, and dengue throughout the tropics (27) , have raised the
profile of these services.
Questions related to international health and the potential scenario
of an unusual, imported, dangerous disease are now addressed in detailed
documents. These documents on the management of suspected cases of virulent
infectious diseases recognize that surveillance is the weakest link in
the defence against the importation of emerging and re-emerging infectious
diseases (28-30) . Rapid international travel can permit even
communicable infectious diseases with short incubation periods to bypass
several international borders before their clinical manifestation. By
the time patients present to medical attention, they may be far from the
epicentre of disease activity and an early correct diagnosis may be problematic.
The new frontier for presentation of imported communicable diseases is
likely to be the emergency room or a primary caregiver's office, and it
could be anywhere in the country.
The use of policy documents to control the importation of virulent communicable
diseases is likely to have very limited success unless accompanied by
the ability to:
-
put practical practice guidelines into the hands of primary caregivers
throughout the country, and
-
communicate when a new potentially "importable" disease has appeared.
This has implications for international disease surveillance and management
as well as for local emerging diseases, such as those caused by hantaviruses,
multiple-drug resistant organisms (e.g. Mycobacterium tuberculosis,
Streptococcus pneumoniae, vancomycin-resistant Enterococcus),
and virulent disease syndromes (e.g. Group A streptococcal disease, toxic-shock
syndrome, Lyme disease), which may have significant public-health impacts
as well. Accurate and timely reporting to the health-care delivery site
will be the challenge for the foreseeable future. The appendix contains
the addresses of the provincial and federal contacts for questions related
to public- and quarantine-health issues.
Practice Point
Rapid international travel has allowed the possibility of exotic and emerging
infectious diseases to be acquired in one locality and then to present
clinically thousands of miles away. A high degree of suspicion must be
maintained and contact made with a tropical medicine or infectious disease
expert, medical officer of health, or the federal health department when
clinical questions arise.
Recommendation 2
-
Practical practice guidelines should be made available to primary
health-care givers to assist in the assessment of emerging and re-emerging
communicable infectious diseases.
-
Communications systems should be developed that will permit notification
of these diseases and other relevant information to be rapidly and
accurately conveyed throughout the health-care system.
Category A
Good evidence to support a recommendation for use.
Grade III
Evidence from opinions of respected authorities on the basis of clinical
experience, descriptive studies, or reports of expert committees.
Appendix
Provincial and Federal Contacts for Questions Related to Public- and
Quarantine-Health Issues
Alberta
Dr. John Waters
Director, Communicable Disease Control and Epidemiology,
Alberta Health
10030-107th Street
Edmonton, AB, T5J 3E4
Office: (403) 427-5263
FAX: (403) 422-6663
|
British Columbia
Dr. John Millar
Chief Medical Officer, Province of British Columbia
2-1810 Blanchard Street
Victoria, BC, V8V 1X4
Office: (604) 952-0876
FAX: (604) 952-0877
|
Manitoba
Dr. John Guilfoyle
Chief Medical Officer of Health,
Manitoba Health
301- 800 Portage Avenue
Winnipeg, MB, R3G 0N4
Office: (204) 945-6839
FAX: (204) 948-2204
|
Newfoundland
Dr. Faith Stratton
Director, Disease Control and Epidemiology,
Department of Health
West Block, Confederation Building
P.O. Box 8700
St. John's, NF, A1B 4J6
Office: (709) 729-3430
FAX: (709) 729-5824
|
New Brunswick
Dr. Denis Allard
Chief Public Health Officer
520 King Street, 2nd Level
Charleton Place, P.O. Box 5100
Fredericton, NB, E3B 5G8
Office: (506) 453-2323
FAX: (506) 453-8702
|
Northwest Territories
Dr. Ian Gilchrist
Chief Medical Health Officer, Department of Health
P.O. Box 1320, Center Square Tower
Yellowknife, NT, X1A 2L9
Office: (403) 920-8946
Emergency: (403) 873-8250
FAX: (403) 873-0266
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Nova Scotia
Dr. Jeff Scott
A/Provincial Epidemiologist, Department of Health and Fitness
1690 Hollis St., 11th Floor
P.O. Box 488
Halifax, NS, B3J 2R8
Office: (902) 424-8698
FAX: (902) 424-0558
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Ontario
Dr. Richard Schabas
Director, Public Health Branch, and
Chief Medical Officer of Health
5700 Yonge Street, 8th Floor
Toronto, ON, M2M 4K5
Office: (416) 327-7392
FAX: (416) 327-7439
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Prince Edward Island
Dr. Lamont Sweet
Chief Health Officer, Department of Health and Social Services
P.O. Box 2000, 1616 Fitzroy
Charlottetown, PE, C1A 7N8
Office: (902) 368-4996
FAX: (902) 368-4969
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Québec
Dr. Christine Colin
Sous-ministre adjointe, Direction générale de la santé publique
Ministère de la Santé et des Services sociaux
1075 chemin Ste-Foy, 16e étage,
Québec, QC, G1S 2M1
Office: (418) 646-3487
FAX: (418) 528-2651
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Saskatchewan
Dr. David Butler-Jones
Laboratory and Disease Control, Services Branch,
Saskatchewan Health
Room 130, 3211 Albert Street
Regina, SK, S4S 5W6
Office: (306) 787-6716
FAX: (306) 787-9576
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Yukon
Dr. Hilary Robinson
Community Health Specialist
2 Hospital Road
Whitehorse, YT, Y1A 3H8
Office: (403) 667-8356
FAX: (403) 667-8338
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Canada
Dr. Rudi Nowak
Director, Quarantine Health Services
Office for Special Health Initiatives
Laboratory Centre for Disease Control
Tunney's Pasture
Ottawa, ON, K1A 0L2
Office: (613) 954-3236
FAX: (613) 952-8286
|
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