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← Infectious diseases, microbiology and sexual health indexChapter sections
OverviewAetiologyPathophysiologyClinical features and red flagsInvestigationsDifferential diagnosisManagementComplicationsMonitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Fever in the returning traveller

Infectious diseases, microbiology and sexual health · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

RapidFull
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Time-critical presentation

Any unwell traveller from a malaria-risk area needs urgent malaria testing, even if prophylaxis was taken. Isolate and contact infection and health-protection specialists immediately for bleeding, unexplained shock, severe respiratory illness or epidemiology compatible with a high-consequence infectious disease.

Overview

Assess fever after international travel by stabilising first, excluding malaria immediately, reconstructing exposure and incubation, applying isolation early and selecting targeted microbiology before empirical treatment.

Returning-traveller fever combines ordinary UK infections with imported disease. Geography changes prior probability but never replaces assessment for pneumonia, pyelonephritis, COVID-19, endocarditis or drug reaction. The safest sequence is ABCDE, transmission risk, malaria exclusion, exposure-incubation timeline, syndrome examination and targeted sampling.

Malaria testing is urgent and may need repetition when initial microscopy or rapid testing is negative but suspicion remains. Severe malaria can cause confusion, acidosis, hypoglycaemia, jaundice, renal injury and respiratory distress. Early specialist advice is essential because treatment and level of care depend on species, parasitaemia and organ involvement.

High-consequence infections are uncommon but operationally important. Recent outbreak information, country, healthcare exposure, animal contact, bleeding and severe respiratory illness determine isolation and referral. Staff should use the designated pathway rather than collecting unplanned specimens that might expose laboratory personnel.

Key points

  • Ask exactly where and when the patient travelled, including stopovers, urban versus rural setting, dates, season and illness onset; incubation time removes many impossible diagnoses.

Aetiology

01

Vector-borne infection

Malaria, dengue, chikungunya, rickettsial disease and other infections follow mosquito or tick exposure, with geography and incubation narrowing likelihood.

02

Food and water exposure

Enteric fever, hepatitis A or E and bacterial or protozoal gastrointestinal infections arise from contaminated food, water or sanitation failures.

03

Animal and environmental contact

Fresh water, livestock, wildlife, caves, soil and arthropods create risks including schistosomiasis, leptospirosis, brucellosis and fungal infection.

04

Human and healthcare exposure

Sexual contact, medical procedures, mass gatherings, sick contacts and funerals may transmit blood-borne, respiratory or high-consequence infections.

Pathophysiology

  1. 1
    Pathogen entry

    Organisms enter through skin, vectors, respiratory mucosa, gastrointestinal tract or blood and establish local or systemic infection.

  2. 2
    Bloodstream dissemination

    Malaria parasites, bacteria, viruses or fungi spread through blood, producing fever and multi-organ manifestations beyond the entry site.

  3. 3
    Host inflammatory response

    Innate immune cytokines reset temperature and alter endothelium, coagulation and perfusion; an excessive response can cause shock and organ injury.

  4. 4
    Organ-specific tropism

    Different pathogens preferentially affect erythrocytes, liver, endothelium, marrow, nervous system or lung, creating the discriminating syndrome pattern.

Clinical features and red flags

Possible falciparum malariaRed flag

Fever with rigors, headache, cytopenia, jaundice, confusion, acidosis or renal injury after malaria-area travel is an emergency even without a regular fever pattern.

Enteric fever patternRed flag

Sustained fever, abdominal symptoms, relative bradycardia, hepatosplenomegaly or travel with unsafe food and water raises typhoid or paratyphoid disease.

Arboviral patternRed flag

Acute fever with rash, severe myalgia, arthralgia, retro-orbital pain, leucopenia or thrombocytopenia suggests dengue, chikungunya or another vector-borne virus according to geography.

High-consequence signalRed flag

Bleeding, unexplained shock, severe respiratory syndrome or exposure to outbreaks, healthcare, caves, animals or funerals requires immediate isolation and specialist risk assessment.

Non-travel diagnosis

Focal urinary, respiratory, cardiac or skin findings may reveal an ordinary infection acquired before, during or after travel and should remain in the differential.

Investigations

  1. 01
    Urgent malaria blood films and rapid diagnostic testingFirst step
    Why
    Detect malaria species, parasitaemia and features requiring severe-disease management.
    Interpretation and limitations
    A negative first test does not always exclude low parasitaemia. Repeat according to specialist and laboratory guidance when suspicion persists, and never wait for cyclical fever.
  2. 02
    FBC, blood film, renal, liver, glucose, CRP and blood gas
    Why
    Identify cytopenia, organ dysfunction, hypoglycaemia, eosinophilia and severity.
    Interpretation and limitations
    Thrombocytopenia occurs in malaria and dengue but is not specific. Eosinophilia suggests selected parasitic or drug causes and is often absent early.
  3. 03
    Blood cultures before antibiotics
    Why
    Detect enteric fever, bacteraemia and endovascular infection while preserving susceptibility yield.
    Interpretation and limitations
    Tell the laboratory the travel and antimicrobial history. Prior antibiotics reduce sensitivity, and resistant enteric organisms may require reference testing.
  4. 04
    Syndrome-directed molecular or serological tests
    Why
    Investigate arboviruses, respiratory viruses, HIV and other infections using the correct illness window.
    Interpretation and limitations
    PCR and antibody yield change with time from onset. Cross-reactive serology and past exposure require infection-specialist interpretation.

Differential diagnosis

01

Common UK infection

Pneumonia, pyelonephritis, COVID-19 and skin infection remain frequent and may be unrelated to the itinerary despite compelling travel history.

02

Malaria

Any fever after malaria-area travel requires urgent blood testing because early symptoms are non-specific and prophylaxis does not exclude disease.

03

Enteric or arboviral infection

Food, vector, incubation and laboratory patterns separate typhoid or paratyphoid disease from dengue and other acute viral syndromes.

04

Non-infectious disease

Pulmonary embolism, drug fever, inflammatory disease and malignancy can begin around travel and require ordinary probability-led assessment.

Management

01Travel from malaria regionExclude malaria immediatelyFirst stepAny current or recent fever follows travel to an area with malaria transmission.+
  1. 1Perform ABCDE, check glucose and travel dates, take urgent malaria films and rapid testing and request infection or tropical-medicine advice.
  2. 2Assess severity including consciousness, lactate or acidosis, renal function, jaundice, anaemia, respiratory compromise and parasitaemia; admit and treat promptly when severe or falciparum malaria is possible.
  3. 3Repeat testing when advised if the first result is negative and suspicion remains, while investigating other imported and ordinary infections in parallel.
02Possible high-consequence diseaseProtect staff and contacts earlyExposure and syndrome raise concern about a nationally designated high-consequence infection.+
  1. 1Place the patient in appropriate isolation, restrict non-essential contact, use designated PPE and call the local infectious-disease and health-protection pathway immediately.

Complications

01

Severe malaria

Parasite burden and microvascular sequestration can cause coma, acidosis, hypoglycaemia, anaemia, kidney injury and respiratory failure.

02

Shock and organ failure

Enteric, rickettsial, leptospiral and viral infections can produce capillary leak, myocarditis, hepatitis, renal injury or coagulopathy.

03

Transmission to contacts

Airborne, faecal-oral, sexual and vector-associated pathogens may require isolation, contact tracing, prophylaxis, vaccination or coordinated environmental action through health-protection teams.

04

Delayed diagnosis

Failure to obtain exact geography, incubation and exposure can postpone effective therapy and allow avoidable clinical deterioration.

Monitoring and follow-up

  • Repeat observations, consciousness, glucose, urine output, lactate and organ tests frequently in any unwell traveller because deterioration can be abrupt.
  • For malaria, document species, parasitaemia and clearance according to specialist protocol and arrange follow-up for delayed artesunate-associated haemolysis.
  • Track blood cultures, reference-laboratory tests and serology that may return after discharge, with named responsibility and a reliable contact route.
  • Review isolation and contact actions with health protection as diagnosis and infectious period become clearer.
  • Revisit the travel timeline when tests are negative; an incorrect country, date or exposure assumption can misdirect the entire investigation.

Special situations

Prophylaxis does not exclude malaria

Adherence, absorption, resistance and imperfect efficacy mean a traveller can develop malaria despite taking preventive medicines.

Incubation is a diagnostic test

A disease cannot explain symptoms beginning outside its biological incubation range, so exact travel and onset dates have high discriminating value.

Ordinary infections remain common

A dramatic itinerary can distract from urinary infection, pneumonia, COVID-19 or endocarditis that requires the same evidence-led assessment as at home.

Phone before the specimen

For possible hazardous infections, advance laboratory and specialist communication protects staff and ensures the correct container, route and reference test.

Common pitfalls

  1. 01

    Excluding malaria because prophylaxis was reportedly completed.

  2. 02

    Waiting for a textbook fever cycle before ordering malaria films.

  3. 03

    Collecting hazardous specimens before notifying the laboratory.

  4. 04

    Ordering a broad travel serology panel without using timing and exposure.

  5. 05

    Attributing all illness to travel and missing a common local infection.

Practice

Two practice questions

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Question 1 of 2
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Infectious diseases, microbiology and sexual healthOriginal SBA

First imported-disease exclusion

A traveller returns from Ghana with fever, headache and thrombocytopenia despite taking malaria prophylaxis. What is the most important immediate diagnostic action?

Choose one answer, then submit
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Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • UK malaria diagnosis and treatment guidelinesNational malaria testing, severity and treatment recommendations.
  • UKHSA high consequence infectious diseasesCurrent definitions and specialist operational pathways.
  • UKHSA notifiable disease reportingNotification and health-protection action for imported infections.
  • NHS Fit for TravelNHS travel-risk, malaria and destination information used to reconstruct exposure.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom
  • Malaria is the first exclusion after travel to a risk area because falciparum disease can deteriorate rapidly and prophylaxis does not provide complete protection.
  • Take a precise exposure history: mosquitoes and ticks, fresh water, animals, food and water, sexual contact, healthcare, caves, funerals, mass gatherings and sick contacts.
  • Use early isolation for possible airborne or high-consequence infection before an exhaustive interview; protect staff while urgent clinical care continues.
  • Look for syndrome patterns—rash, jaundice, diarrhoea, eosinophilia, cytopenias, hepatosplenomegaly, neurological change and respiratory failure—without treating any single clue as diagnostic.
  • Discuss unusual samples and empirical treatment with infection or microbiology specialists; malaria films, cultures and molecular tests have timing and handling requirements.
  • Notify suspected notifiable disease on clinical suspicion and coordinate contacts or post-exposure action through the local health-protection team.
  • 05
    Imaging and targeted source samples
    Why
    Assess pneumonia, abscess, hepatobiliary disease, neurological infection or another focal source.
    Interpretation and limitations
    Choose imaging from clinical findings and stability. Discuss hazardous or unusual specimens with microbiology before collection and transport.
  • 2Continue emergency care using trained staff, record exposure details and avoid sending unannounced specimens through routine laboratory routes.
  • 3Follow specialist instructions for transfer, sampling, notification, staff exposure and environmental control while maintaining confidentiality.
    • 03Stable undifferentiated feverUse incubation and exposure to focus testsThe traveller is physiologically stable and immediate malaria and high-consequence pathways have been addressed.+
    1. 1Construct a country-by-date timeline and map food, water, vector, animal, freshwater, sexual, healthcare and medicine exposures against illness onset.
    2. 2Examine for rash, nodes, jaundice, organomegaly, murmur, focal chest, abdominal or neurological signs and obtain targeted cultures and laboratory tests.
    3. 3Review results with infection specialists, give syndrome-directed treatment when supported and provide explicit deterioration and pending-result follow-up.
    Key medicines and prescribing safety2 treatments · regimens, roles and cautions+
    First-choice emergency treatment for severe falciparum malaria in UK specialist care.

    Intravenous artesunate

    Give 2.4 mg/kg intravenously at 0, 12 and 24 hours, then every 24 hours until oral treatment is tolerated; after at least three doses, complete a full specialist-selected oral combination course.

    Do not delay for transfer or perfect species confirmation when severe malaria is likely. Monitor glucose, parasitaemia and organ failure; arrange full blood count and haemolysis surveillance after discharge because delayed artesunate-associated haemolysis can emerge over the following 4 weeks.

    Treats selected uncomplicated malaria when species, severity, region and prior prophylaxis make the regimen suitable.

    Atovaquone with proguanil

    For adults over 40 kg with selected uncomplicated falciparum malaria, give four 250/100 mg tablets orally once daily for three days with food.

    Not for severe malaria. Give with food, repeat a dose vomited within 1 hour, and seek an alternative after repeated vomiting. Review severe renal impairment, pregnancy and anticoagulant monitoring, avoid reusing a failed prophylactic drug, and confirm species-specific follow-up with the specialist service.