GC103 Fever After Travelling
Fever occurring in a patient who has recently traveled, particularly to tropical or endemic regions, requiring systematic evaluation for infections such as malaria, dengue, typhoid, and other travel-related diseases.
Fever in the Traveller
Lecture Map
A returning traveller with fever is a diagnostic emergency until you have excluded life-threatening, transmissible infections — above all, malaria and enteric fever. The approach is systematic: take a meticulous travel and exposure history, use incubation periods to narrow the differential, investigate aggressively, and treat empirically where delay could kill.
- Understand the spectrum of health risks associated with international travel.
- Know how to take a structured travel history for a febrile returning traveller.
- Match exposure types to likely pathogens.
- Construct a differential diagnosis using geography, incubation period, activities, and clinical features.
- Recognise infectious disease emergencies — especially falciparum malaria and enteric fever (typhoid).
- Know the principles of malaria diagnosis, treatment, and chemoprophylaxis.
- Understand travellers' diarrhoea: epidemiology, risk factors, prevention, and management.
- Appreciate epidemic/pandemic-prone infections and antibiotic-resistant organisms as considerations in returned travellers.
This lecture is a favourite for minicase and SAQ stems (see 2019 minicase Case 1 — a classic typhoid case from Bangladesh) and for MCQ stems on malaria prophylaxis (2023 MCQ Q78). Expect questions on: differential diagnosis of fever in a returned traveller, specific investigations (blood film for malaria, blood/stool culture for typhoid), complications of typhoid (perforation, relative bradycardia), malaria prophylaxis regimens, and conditions requiring isolation in returned travellers with pneumonia (2018 minicase Q11).
2–10% of international travellers will experience a febrile illness either during their travel or within 2 weeks of returning from abroad. [1]
- 39% had fever abroad only; 37% had fever abroad and at home; 24% had fever at home only. [1]
- Why this matters: Many patients present AFTER returning home, so Hong Kong clinicians must maintain a high index of suspicion.
Illness Patterns in Returned Travellers (GeoSentinel / EuroTravNet Data)
| Category | GeoSentinel Global 2007–2011 | EuroTravNet 1998–2018 |
|---|---|---|
| Gastrointestinal | 34.0% | Top diagnosis: Acute diarrhoea (9.3%) |
| Fever/systemic illness | 23.3% | Falciparum malaria (4.4%); all malaria (6.9%) |
| Skin | 19.5% | — |
| Respiratory | 10.9% | — |
| Viral syndromes | — | 5.8% |
| Deaths | — | 0.04% |
EuroTravNet: Malaria patients had a 2.5:1 risk ratio of dying compared to patients with all other diagnoses. [1]
This single fact is why the lecture insists: the first principle is "Must recognise infectious disease emergencies." [1]
Health risks include: environmental risks (accidents, motion sickness, altitude, heat/humidity, UV radiation, cold exposure), foodborne and waterborne diseases, vectorborne diseases, zoonoses, sexually-transmitted diseases, bloodborne diseases, airborne diseases, and diseases transmitted from soil and water. [1]
Factors Determining Risk to Travellers
| Factor | Why It Matters |
|---|---|
| Destination | Endemicity of specific pathogens (e.g., Sub-Saharan Africa → malaria; South Asia → typhoid) |
| Duration of visit | Longer stay = cumulative exposure risk |
| Purpose of visit | Business hotel vs. rural village visit vs. humanitarian work |
| Standards of accommodation and food hygiene | Backpackers > luxury travellers for enteric infections |
| Behaviour of the traveller | Sexual activity, adventure sports, barefoot walking, food choices |
Medical counselling preferably 4–6 weeks before the journey, particularly if vaccination(s) may be required. [1]
Components:
- Assessment of health risks associated with travel destination.
- Vaccinations (e.g., Hepatitis A, Typhoid, Yellow Fever, Japanese Encephalitis).
- Antimicrobial prophylaxis (e.g., malaria chemoprophylaxis).
- Usual medications — ensure adequate supply.
- Precautions during travel — food/water hygiene, vector avoidance, safe sex.
- Medical kit — ORS, antimotility agents, empirical antibiotics, insect repellent.
Follow-Up After Travel
Indicated if they: (1) Suffer from a chronic disease; (2) Experience illness in the weeks following their return home; (3) Consider that they have been exposed to a serious infectious disease while travelling; (4) Have spent more than 3 months in a developing country. [1]
4. Clinical Approach to the Febrile Returning Traveller
4.1 History
Onset, incubation period, duration, symptomatology (local and systemic), and fever pattern. [1]
- Incubation period is the single most powerful narrowing tool. If you know when the traveller was in an endemic area and when symptoms started, you can include or exclude diagnoses.
- Fever pattern — historically described (tertian for P. vivax/ovale, quartan for P. malariae), but usually not helpful in practice. [1] Why? Because partial immunity, prior antimalarials, and mixed infections blur classic patterns.
Including intermediate stops, mode of travel, exact dates and places, sexual exposure, needle and blood exposure (drug abuse, tattoos, body piercing, injection, medical procedures), animal/arthropod contacts (any type of animals; bites, scratches, licks; spelunking), exposure to water (swimming, walking, rafting), food/drink exposure, and prophylactic measures. [1]
Exam Tip: Don't Forget Prophylactic Measures
Always ask what prophylactic measures were taken. A patient who was on malaria chemoprophylaxis with good compliance is less likely (but not zero risk) to have malaria. A patient who stopped prophylaxis early or had poor compliance remains at risk.
This table is extremely high yield and directly from the lecture. Expect MCQ/SAQ stems that give an exposure and ask you to identify the pathogen.
| Exposure | Potential Infective Complications |
|---|---|
| Sex, blood, body fluids, surgical operations, IV drug use | Hepatitis B and C, HIV infection, syphilis, monkeypox/Mpox |
| Tattoos, body piercing, other body modification procedures | Hepatitis B and C, HIV infection, syphilis, non-tuberculous mycobacterial infections |
| Hospitalization | Antibiotic-resistant bacteria (colonization or infection), bloodborne viruses |
| Ingestion of raw or undercooked food | Bacterial and viral gastroenteritis, protozoal and helminth infections, brucellosis, listeriosis, toxoplasmosis, hepatitis A and E |
| Soil | Histoplasmosis, coccidioidomycoses, other endemic mycoses, cutaneous larva migrans, strongyloidiasis |
| Freshwater | Schistosomiasis (Katayama fever), leptospirosis |
| Arthropod bites | Dengue, chikungunya, Zika virus infection, rickettsioses, relapsing fevers, malaria, babesiosis, leishmaniasis, trypanosomiasis, dirofilariasis |
| Dog, bat and other animal bites | Rabies, bat rabies, herpes B virus infection, bite wound infections |
| Animals and animal products | Hantaviruses, Lassa fever, Crimean-Congo haemorrhagic fevers, avian influenza, MERS, plague, rat-bite fevers, leptospirosis, Q fever, brucellosis, tularaemia, anthrax, psittacosis |
General: Skin lesions (rash, eschar, bite marks, needle marks), jaundice, bleeding tendencies. Systemic: Lymphadenopathy, organomegaly, localizing signs (e.g. meningism). [1]
Why each sign matters:
- Eschar → Scrub typhus or other rickettsioses (look in axillae, groin, behind ears).
- Jaundice → Malaria (haemolysis), viral hepatitis, leptospirosis.
- Bleeding tendencies → Viral haemorrhagic fevers (Ebola, dengue haemorrhagic fever) — triggers isolation consideration.
- Rash → Rose spots (typhoid), maculopapular (dengue, chikungunya, rickettsial), petechial/purpuric (meningococcaemia, VHF).
- Hepatosplenomegaly → Malaria, enteric fever, visceral leishmaniasis, brucellosis.
- Meningism → Bacterial meningitis, viral encephalitis (Japanese encephalitis if travel to endemic areas).
4.4 Investigations
| Investigation | Why |
|---|---|
| CBC with differential | Leukopenia in typhoid/dengue; eosinophilia in helminth; thrombocytopenia in malaria/dengue; atypical lymphocytes in EBV/CMV |
| Coagulation studies | DIC in severe malaria, VHF |
| Liver function tests | Hepatitis, severe malaria, leptospirosis |
| Renal function tests | Severe malaria, leptospirosis |
| Creatine kinase | Leptospirosis (skeletal muscle involvement) |
| CXR | Pneumonia, TB, Legionella |
| CT/MRI | As indicated (e.g., brain abscess, amoebic liver abscess) |
Microscopy: Blood film (thick and thin), stool microscopy. Culture: Blood, stool, urine, tissues. Serology. Tissue biopsy (microbiology and histopathology). As indicated. [1]
5. Constructing the Differential Diagnosis
Ask: (1) What diagnoses are possible based on the geographical areas visited? (2) What diagnoses are possible based on the time of travel (incubation periods)? (3) What diagnoses are more likely based on activities, exposures, host factors, and clinical/laboratory findings? (4) Among the possible diagnoses, what is/are treatable, transmissible, or both? [1]
High Yield: The 4-Question Framework for Differential Diagnosis
This framework is the core of the lecture. In an SAQ or minicase, structure your answer around these four questions. The last question — "what is treatable and transmissible?" — is the one that determines urgency. Malaria is both. Typhoid is both. VHFs are transmissible. These cannot wait.
Malaria, respiratory tract infections, diarrhoeal disease, enteric fevers, genitourinary infections, arboviruses (e.g. dengue, chikungunya), and viral syndromes. [1]
| Category | Examples |
|---|---|
| Systemic infections | Malaria, rickettsioses, dengue, chikungunya, Zika, enteric fever, brucellosis, Q fever, leptospirosis |
| Respiratory tract infections | Viral infections, pneumonia, legionellosis |
| Enteric infections | Gastroenteritis, cholera, dysentery, giardiasis, amoebiasis, Norovirus |
| STDs/bloodborne viruses | HIV, HBV, HCV, other STIs |
Epidemic- or pandemic-prone infections: SARS (2003), pandemic influenza (2009), MERS (since 2012), avian/animal influenza viruses, viral haemorrhagic fevers (e.g. Ebola, 2014), Zika virus infection (since 2015), COVID-19 (since 2020), monkeypox/Mpox (since 2022). [1]
Potential for local transmission: malaria, dengue, chikungunya, VHFs, Zika. [1]
Antibiotic-resistant bacteria: ESBL- and carbapenemase-producing Enterobacterales, MRSA, VRE, multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa. Highest risks in Indian subcontinent, Southeast Asia, Africa. Multi-resistant Candida auris. [1]
Re-emerging infectious diseases: e.g. measles in adults. [1]
Understanding incubation periods lets you include or exclude diagnoses based on the timeline between exposure and symptom onset.
| Incubation Period | Diseases |
|---|---|
| < 2 weeks (short) | Dengue (4–7 days), chikungunya (2–12 days), influenza (1–4 days), rickettsial diseases (5–14 days), travellers' diarrhoea (1–3 days), typhoid/paratyphoid (7–14 days), malaria P. falciparum (7–30 days, usually ≥7 days), plague, VHFs |
| 2–6 weeks (intermediate) | Malaria P. vivax/ovale (12–17 days, but can be months), hepatitis A (15–50 days), hepatitis E (15–60 days), acute HIV seroconversion (2–4 weeks), leptospirosis (2–30 days), brucellosis (1–8 weeks), Q fever (2–3 weeks) |
| > 6 weeks (long) | TB (weeks to years), hepatitis B (6 weeks – 6 months), visceral leishmaniasis (weeks–months), malaria P. vivax/ovale relapse (months–years), amoebic liver abscess (weeks–months), rabies (weeks–months) |
Exam Trap: Malaria Incubation
The lecture states malaria should be suspected "after 7 days of stay in an endemic area." This means the minimum incubation for P. falciparum is ~7 days. A patient who left an endemic area only 3 days ago and already has fever is LESS likely to have malaria (but not impossible). However, malaria can present months later (especially P. vivax/ovale due to hypnozoites in the liver). So always consider malaria regardless of timing if there was exposure to an endemic area.
6. Malaria — The Must-Not-Miss Diagnosis
Impaired consciousness, acidosis, hypoglycaemia, severe malarial anaemia, renal impairment, jaundice, pulmonary oedema, significant bleeding, shock, hyperparasitaemia (P. falciparum, > 10%). [1]
Why each feature occurs:
- Impaired consciousness — Sequestration of parasitized RBCs in cerebral microvasculature → cerebral malaria.
- Acidosis — Tissue hypoxia from anaemia + microvascular obstruction → lactic acidosis.
- Hypoglycaemia — Parasite glucose consumption + quinine-induced insulin secretion.
- Severe anaemia — Haemolysis of parasitized RBCs + suppressed erythropoiesis + splenic clearance.
- Renal impairment — Acute tubular necrosis from haemoglobinuria, hypovolaemia, sequestration.
- Jaundice — Haemolysis + hepatocyte dysfunction.
- Pulmonary oedema — Increased capillary permeability (non-cardiogenic) or fluid overload.
- Hyperparasitaemia ( > 10%) — Massive RBC invasion; overwhelms splenic clearance capacity.
Falciparum malaria is a medical emergency. Accounts for most of the mortality due to malaria. Prompt initiation of treatment ± ICU monitoring. [1]
Demonstration of Plasmodium parasites: Blood smear (peripheral blood, marrow blood), thick and thin films, tissue samples/post-mortem examination, parasitaemia level, antigen detection, PCR. [1]
| Method | Purpose |
|---|---|
| Thick film | Higher sensitivity — concentrates parasites from a larger volume of blood; better for detection |
| Thin film | Allows species identification and parasitaemia quantification |
| Antigen detection (RDT) | Rapid point-of-care; detects HRP-2 (P. falciparum) or pLDH (all species); useful when microscopy unavailable |
| PCR | Most sensitive; detects low-level parasitaemia and mixed infections; not always available acutely |
One set of negative blood film does not exclude malaria. If the first blood smear is negative and suspicion is high: Repeat 3 smears over 48 h, or use alternative tests (antigen, PCR). [1]
High Yield: Negative Blood Film Does NOT Exclude Malaria
This is a classic exam point. Parasitaemia can be cyclical and below detection threshold. You must repeat blood films (at least 3 over 48 hours) before you can confidently say a patient does not have malaria. If clinical suspicion remains high after 3 negative smears, use antigen detection or PCR.
| Severity | Treatment |
|---|---|
| Severe malaria | Artesunate IV (first-line) or Quinine IV (if artesunate unavailable) |
| Uncomplicated malaria | Atovaquone-proguanil, artemisinin-combination therapy (ACT), mefloquine, oral quinine + doxycycline |
| P. vivax / P. ovale | Add primaquine or tafenoquine (to eliminate hypnozoites in the liver and prevent relapse) |
Why primaquine/tafenoquine for P. vivax/ovale? These species form hypnozoites — dormant forms in hepatocytes that can reactivate months to years later. Primaquine and tafenoquine are the only drugs that kill hypnozoites. Must check G6PD status before prescribing (risk of haemolytic anaemia in G6PD-deficient patients).
6.5 Prevention of Malaria
Long-sleeve shirts, insect repellents (DEET, IR3535, picaridin), bednets, avoidance of exposure. [1]
Common options: Atovaquone-proguanil, doxycycline, mefloquine. Must be started before (1 day to 3 weeks depending on the drug regimen) the journey, continue throughout the stay in endemic areas, and continue after returning to home country (7 days to 4 weeks depending on the drug regimen). [1]
| Drug | Start Before Travel | Continue After Return | Notes |
|---|---|---|---|
| Atovaquone-proguanil | 1–2 days | 7 days | Short tail → good compliance; GI side effects |
| Doxycycline | 1–2 days | 4 weeks | Photosensitivity, oesophageal ulceration; also protects against rickettsiae and leptospirosis |
| Mefloquine | 2–3 weeks | 4 weeks | Neuropsychiatric side effects (vivid dreams, anxiety); weekly dosing; longer lead-in allows detection of side effects before travel |
2023 MCQ Q78: Correct answer is D — "Start antimalarial prophylaxis before, during and after the travel." There is no malaria vaccine for routine traveller use (RTS,S/AS01 is for children in endemic areas, not standard traveller prophylaxis). You cannot "bring antibiotics in case of fever" as a substitute for prophylaxis. Avoiding dirty water does not prevent malaria (it is mosquito-borne, not waterborne). [3]
Incidence chart shows imported cases: peak ~300+ in mid-1990s, declining to ~20–30 in recent years (data up to 8/2023). [1]
All cases in Hong Kong are imported. This means every case presents as "fever after travelling."
7. Enteric Fever (Typhoid / Paratyphoid)
Salmonella Typhi (typhoid), Salmonella Paratyphi A, B, C (paratyphoid), Yersinia enterocolitica, Brucella, Campylobacter fetus. [1]
The term "enteric fever" is broader than just typhoid, but in exams, Salmonella Typhi is the prototypical answer.
The 2019 minicase is a near-perfect case study of this lecture [4]:
- 23-year-old female, returned from Bangladesh
- Recurrent fever for 2 weeks
- Constipation in week 1 → non-bloody diarrhoea in week 2 (classic biphasic GI pattern of typhoid)
- Did not drink exclusively bottled water (faecal-oral transmission)
- Multiple mosquito bites (must also consider malaria/dengue)
Physical examination clues:
- High fever of 40°C with pulse rate 50 bpm → "Relative bradycardia" (also called Faget's sign) [4] — the heart rate does not rise proportionally with fever. Usually fever of 40°C should produce HR ~120 bpm. A pulse of 50 is strikingly slow.
- Rose spots: "A few rashes found on the lower chest and abdomen" [4] — these are faint, salmon-pink, blanching macules/papules, typically on the trunk.
- Abdominal distension, RLQ tenderness — the terminal ileum has Peyer's patches, the primary site of S. Typhi invasion and ulceration.
From the 2019 minicase (Q5: "Name five investigations to confirm your diagnosis"):
- Blood culture — Most important in week 1–2 of illness (sensitivity ~60–80%).
- Stool culture — Becomes more positive in weeks 2–3.
- Bone marrow culture — Highest sensitivity (~90%); done if blood/stool cultures are negative.
- Widal test (serology) — Detects antibodies to O and H antigens; poor sensitivity/specificity; rising titres more useful than single titre.
- CBC — Leukopenia with relative lymphocytosis (not leukocytosis); may show anaemia.
- Blood film for malaria — Must exclude co-existing malaria (mosquito bites!).
From the 2019 minicase Section 4: Patient developed shock and severe diffuse abdominal pain on day 2 of antibiotics → emergency laparotomy [4]. This is intestinal perforation — the most feared complication.
| Complication | Mechanism |
|---|---|
| Intestinal perforation | Necrosis and ulceration of Peyer's patches → free perforation → peritonitis |
| Intestinal haemorrhage | Erosion into blood vessels in ulcerated Peyer's patches |
| Jarisch-Herxheimer reaction | Massive release of endotoxin when antibiotics kill large numbers of organisms → transient worsening of fever, shock |
| Relapse | Organisms persist in gallbladder/bone marrow; carrier state |
Exam Trap: Why Did the Patient Deteriorate After Starting Antibiotics?
If a typhoid patient develops shock after starting antibiotics, consider the Jarisch-Herxheimer reaction (endotoxin release). If they develop diffuse abdominal pain with peritonism, consider intestinal perforation — the necrotic Peyer's patches can perforate as inflammation peaks, sometimes coinciding with early treatment. The 2019 minicase tested exactly this scenario.
From the 2019 minicase Section 3: "Gram smear demonstrated bacteria stained in red colour" → Gram-negative bacilli (rods). [4] Salmonella Typhi is a Gram-negative, facultative anaerobic rod of the family Enterobacteriaceae.
8. Travellers' Diarrhoea
30–50% of travellers from industrialized to developing countries will develop travellers' diarrhoea. 90% in the first 2 weeks, especially first 3–4 days. Mean duration: 3–4 days. [1]
Why so common? Travellers lack local enteric immunity and are suddenly exposed to new enteropathogenic strains via contaminated food/water.
Destination, country of origin, travel behaviour (accommodation, food, standard of hygiene, food habits), and at-risk populations: hypo- or achlorhydria (e.g. PPI users), extremes of age, immunosuppressed (HIV/AIDS, steroids, transplant recipients). [1]
Why achlorhydria matters: Gastric acid is a key defence against ingested pathogens. PPIs remove this barrier → lower infectious dose needed.
Pre-travel counselling and education, behavioural modification/precautions, vaccination, pharmacological (antimicrobial) prophylaxis. [1]
- "Boil it, cook it, peel it, or forget it" — the traveller's food-safety mantra.
- Antimicrobial prophylaxis is generally NOT recommended for most travellers (risk of resistance, side effects) but may be considered for high-risk individuals (immunocompromised, short critical trips).
Fluid and electrolyte replacement (ORS), symptomatic treatment with loperamide (NOT for inflammatory or invasive diseases), empirical antimicrobial therapy: ciprofloxacin, azithromycin, rifaximin, bismuth subsalicylate. [1]
Growing problem of antibiotic resistance, especially towards fluoroquinolones. [1]
| Treatment | When to Use | Caveats |
|---|---|---|
| ORS | Always — cornerstone of management | Prevents dehydration regardless of cause |
| Loperamide | Watery, non-bloody diarrhoea without high fever | NOT for inflammatory/invasive disease — can worsen toxic megacolon, delay clearance of invasive organisms |
| Ciprofloxacin | Empirical; especially effective against ETEC, Shigella | Increasing resistance, especially in South/Southeast Asia |
| Azithromycin | Preferred in South Asia (fluoroquinolone resistance); safe in children/pregnancy | Broader coverage |
| Rifaximin | Non-invasive diarrhoea (watery only) | Non-absorbed; NOT for invasive/febrile dysentery |
9. Other Important Infections in Returned Travellers
- Enteric infections — travellers' diarrhoea, enteric fever, dysentery (bacillary and amoebic).
- Arthropod-borne infections — malaria, dengue, chikungunya, Zika, rickettsioses.
- STDs including HIV, monkeypox/Mpox.
- Leptospirosis — freshwater exposure; Weil's disease (severe form with jaundice, renal failure, haemorrhage).
- Viral hepatitis — HAV/HEV (food), HBV/HCV (parenteral/sexual).
- Others — cholera, giardiasis, VHFs, hantavirus, Japanese encephalitis, rabies — relatively uncommon.
- Acquisition of antibiotic-resistant bacteria — carbapenem-resistant Enterobacterales, extensively drug-resistant S. Typhi, MDR-TB, Candida auris.
- Re-emerging infectious diseases — measles in adults.
- Don't forget common ubiquitous infections (RTI, UTI) which may not be related to travel. Some RTIs are geographically restricted — e.g., MERS-CoV associated with travel to the Middle East, especially camel contact. [2]
From the 2018 minicase (Q11): "Name two suspected conditions that should be admitted to the isolation ward in returning travellers presenting with pneumonia." [5]
Likely answers:
- Pulmonary TB (especially MDR-TB) — Airborne transmission; returned from Philippines (high TB burden country).
- MERS-CoV infection — Travel to Middle East.
- Avian influenza (e.g., H5N1, H7N9) — Travel to areas with poultry outbreaks.
- COVID-19 — During pandemic era.
- Viral haemorrhagic fevers — If travel to West/Central Africa.
Isolation Triggers in Returned Traveller with Pneumonia
When a returned traveller presents with pneumonia, always consider airborne/droplet-transmitted infections that require isolation: TB, MERS, avian influenza, COVID-19, and VHFs. The 2018 minicase specifically tested this. The patient was a domestic helper who returned from the Philippines — think TB and COVID-19 as top isolation diagnoses.
These are all mosquito-borne (Aedes aegypti/albopictus) and present similarly but with distinguishing features:
| Feature | Dengue | Chikungunya | Zika |
|---|---|---|---|
| Fever | High (breakbone fever) | High | Low-grade or afebrile |
| Arthralgia | Mild | Severe, symmetrical, small joints — the distinguishing feature (name means "that which bends up") | Mild |
| Rash | Maculopapular (day 3–7) | Maculopapular | Maculopapular (prominent) |
| Complications | DHF/DSS (↑ vascular permeability → shock) | Chronic arthritis | Congenital Zika syndrome (microcephaly), Guillain-Barré |
| Diagnosis | NS1 antigen (early), IgM/IgG serology | Serology, PCR | PCR (blood, urine), serology |
- 35-year-old man, good past health, fever + confusion for 2 days, generalised tonic-clonic seizure, returned from Shanghai 1 week ago, no focal neurological deficit.
- (a) Most likely clinical diagnosis: Viral encephalitis (fever + confusion + seizure + no focal deficit).
- (b) Investigations: Lumbar puncture (CSF analysis), brain MRI, EEG.
- (c) Important infective causes: Japanese encephalitis (endemic in East/Southeast Asia), herpes simplex encephalitis, enteroviral encephalitis.
- (d) Empirical antimicrobial therapy: IV aciclovir (to cover HSV encephalitis — the one treatable viral encephalitis you cannot afford to miss) + IV ceftriaxone (to cover bacterial meningitis empirically).
| Related Lecture | Connection |
|---|---|
| GC 048: Fever | General fever workup; PUO definition; non-travel-related causes |
| GC 049: Fever after blood transfusion | Transfusion reactions vs. infection |
| GC 052: Fever and purulent sputum | Pneumonia in returned traveller (consider TB, Legionella) |
| GC 061: HIV positive | HIV as a travel-acquired infection; post-exposure prophylaxis after needle stick |
| GC 096: Why do I always get sick | Immunodeficiencies → higher susceptibility to travel-acquired infections |
| GC 101: Diagnosis of infections | Microscopy, culture, serology, molecular diagnostics |
| GC 102: Fever after chemotherapy | Immunocompromised host; different pathogen spectrum |
| GC 106: Practical issues in antibiotic use | Antibiotic resistance in travel-acquired infections |
| GC 239: Viral hepatitis | HAV/HEV as travel-acquired enteric hepatitis |
Likely Exam Questions
-
"A 30-year-old man returns from Kenya with high fever for 3 days. He did not take malaria prophylaxis. What is your most important differential diagnosis and how would you investigate?"
- Markscheme: Malaria (P. falciparum); thick and thin blood films × 3 over 48h; malaria antigen (RDT); CBC, LFT, RFT, coagulation studies; blood culture (to exclude concomitant bacteraemia).
-
"List 5 features of severe malaria."
- Markscheme: Impaired consciousness, acidosis, hypoglycaemia, severe anaemia, renal impairment, jaundice, pulmonary oedema, significant bleeding, shock, hyperparasitaemia ( > 10%).
-
"A 25-year-old woman returns from Bangladesh with fever, constipation progressing to diarrhoea, and relative bradycardia. Name the diagnosis and 5 investigations."
- Markscheme: Typhoid fever (S. Typhi); blood culture, stool culture, bone marrow culture, Widal test, CBC (leukopenia), blood film for malaria.
-
"What malaria chemoprophylaxis options are available? When should they be started and stopped?"
- Markscheme: Atovaquone-proguanil (start 1–2 days before, continue 7 days after), doxycycline (start 1–2 days before, continue 4 weeks after), mefloquine (start 2–3 weeks before, continue 4 weeks after).
-
"Why is loperamide contraindicated in invasive/inflammatory diarrhoea?"
- Markscheme: Reduces intestinal motility → delays clearance of invasive organisms; risk of toxic megacolon in inflammatory colitis (e.g., Shigella dysentery, C. difficile).
- Malaria prophylaxis timing and drug choice (2023 Q78)
- Exposure-pathogen matching (freshwater → schistosomiasis; tattoo → HBV/HCV; arthropod bite → dengue/malaria)
- One negative blood film does not exclude malaria
- Relative bradycardia + rose spots = typhoid
- Conditions requiring isolation in returned travellers with respiratory symptoms
High Yield Summary
1. First Principle: Must recognise infectious disease emergencies in returned travellers — especially malaria and enteric fever.
2. Take a COMPLETE travel history: destinations, dates, exposures (food, water, sex, needles, animals, arthropods), prophylactic measures, and intermediate stops.
3. Use incubation periods to narrow differentials (short < 2 weeks: dengue, malaria, typhoid, rickettsiae; intermediate 2–6 weeks: hepatitis A/E, leptospirosis; long > 6 weeks: TB, hepatitis B, visceral leishmaniasis).
4. Malaria: Suspect in ANY acute febrile illness with possible exposure. One negative blood film ≠ exclusion — repeat ×3 over 48h. Severe malaria = medical emergency → IV artesunate. P. vivax/ovale need primaquine/tafenoquine for hypnozoites. Chemoprophylaxis must start BEFORE travel, continue DURING, and continue AFTER return.
5. Enteric fever (Typhoid): Relative bradycardia, rose spots, RLQ tenderness. Blood/stool/bone marrow culture. Complications: intestinal perforation, haemorrhage. Jarisch-Herxheimer reaction after starting antibiotics.
6. Travellers' diarrhoea: 30–50% of travellers; ORS always; loperamide NOT for invasive disease; empirical azithromycin or ciprofloxacin; fluoroquinolone resistance is a growing problem.
7. Consider isolation for returned travellers with pneumonia: TB, MERS, avian influenza, COVID-19, VHFs.
8. Antibiotic-resistant organisms are increasingly acquired during travel — ESBL, CRE, XDR S. Typhi, Candida auris.
9. Don't forget common infections (UTI, community-acquired pneumonia) that may be unrelated to travel.
Active Recall - Fever After Travelling
[1] Lecture slides: GC 103. Fever after travelling.pdf (all pages/slides) [2] Lecture slides: GC 103. Fever after travelling [Handout].pdf (p2) [3] Past papers: 2023 Fourth Summative MCQ.pdf (Q78) [4] Past papers: 2019 Fourth Summative Mini Case.pdf (Case 1, Sections 1–4) [5] Past papers: 2018 Fourth Summative Minicase.pdf (Q11, Sections 3–4) [6] Past papers: 2019 Fourth Summative SAQ.pdf (Q10)
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