• Initial assessment is aimed primarily at early detection and treatment of falciparum malaria, which can be rapidly fatal

Symptoms and signs

• Temperature >37.5°C in patient presenting after recent overseas travel (e.g. malaria occurring 6 months after travel)
• Falciparum malaria
• 10% of patients are afebrile at presentation
• symptoms take at least 6 days to manifest after arrival in endemic area.
• symptoms usually occur within 2 months of exposure, but may not present for up to 6 months
• Rigors or night sweats imply fever; myalgia or arthralgia do not
• Diarrhoea is non-specific and consistent with malaria, pneumonia, enteric pathogen or any other infective process

Travel history

• Where? - Country and exact locations visited including beaches, jungles, bush etc ( city vs rural)
• for information on outbreaks
• Why? - Business, holiday, visiting relatives
• Accommodation? (e.g. 5-star hotel vs camping)
• When? - Dates of departure and return, and their relation to onset of symptoms
• viral haemorrhagic fevers (VHF) can be excluded if onset of symptoms >21 days after leaving endemic area - for advice on viral haemorrhagic fevers
• for advice regarding Ebola infection
• for advice regarding Middle East Respiratory Syndrome Coronavirus (MERS-CoV)

Incubation periods

• Narrow differential diagnosis by considering incubation periods

Short (<10 days)

• Acute gastroenteritis (bacterial, viral)
• Respiratory tract infection (bacterial, viral including SARS-CoV-2, avian influenza)
• Meningitis (bacterial, viral)
• Arboviral infections (e.g. dengue, Chikungunya)
• Rickettsial infection (e.g. tick typhus, scrub typhus)
• Relapsing fever (Borrelia)

Medium (10-21 days)

• Protozoal
• malaria (Plasmodium falciparum)
• trypanosomiasis (Trypanosoma rhodesiensae)
• acute Chagas' disease

• Viral
• HIV, CMV, EBV, VHF (including Ebola virus disease)
• Middle East Respiratory Syndrome Coronavirus (MERS-CoV)

• Bacterial
• Enteric fever (typhoid and paratyphoid fever)
• brucellosis
• Q Fever
• leptospirosis

Long (>21 days)

• Protozoal
• malaria (including Plasmodium falciparum)
• amoebic liver abscess
• visceral leishmaniasis

• Viral
• viral hepatitis
• HIV
• Other
• filariasis
• schistosomiasis
• TB

What? - Risk activities

• Sexual history - HIV - see HIV testing guideline
• Swimming in fresh water - schistosomiasis (Africa) or rickettsial disease (eastern Europe, Asia and South America)
• Tick bites - rickettsial disease (North and South America, sub-Saharan Africa, coastal Mediterranean)
• Animal/bird contact - avian influenza
• Sickness occurring in fellow travellers or contacts: what? when? - especially important in outbreak situations

Pre-travel history

• Pre-travel immunisations, antimalarials and adherence to them
• Any previous medical history, specifically conditions/treatments that can induce immunosuppression

• Confirm presence of fever
• Look for rashes, bites, jaundice, lymphadenopathy, hepatosplenomegaly, bleeding/bruising

Recommended initial investigations in returning travellers presenting with (undifferentiated) fever

Malaria film +/- dipstick antigen test (RDT)

• Perform in all patients who have visited a tropical country within 1 yr of presentation
• Sensitivity of a thick film read by an expert is equivalent to that of an RDT. However, blood films are necessary for specification and parasite count
• Three thick films/RDTs over 72 hr (as outpatient if appropriate) to exclude malaria with confidence
• Blood films (thick and thin) to reference laboratory for confirmation
• See UK malaria treatment guidelines 2016

FBC

• Neutrophilia suggests bacterial infection
• Lymphopenia: common in viral infection (dengue, HIV) and typhoid
• Eosinophilia (>0.5 x 10⁹/L): incidental or indicative of infectious (e.g. parasitic, fungal) or non-infectious cause
• Thrombocytopenia: >75% of patients with falciparum malaria, dengue, acute HIV, typhoid, also seen in severe sepsis

Blood culture

• Two sets before administering antimicrobials
• Sensitivity of up to 80% in typhoid

Serum save

• Offer HIV test to all patients with pneumonia, lymphocytic meningitis, diarrhoea, unexplained fever - see HIV testing guideline
• If indicated, other serology (e.g. arboviral, brucella)

EDTA for PCR

• Consider if other features suggestive of arboviral infection, VHF

Other bloods

• U&E, LFT, CRP and Chest X-ray

Urinalysis

• Proteinuria and haematuria in leptospirosis
• Haemoglobinuria in malaria (rare)

Stool

• MC&S
• Ova, cysts and parasites (OCP)

Respiratory

• COVID-19 PCR
• Extended viral PCR

• Contact infectious diseases team on same or next working day
• If some conditions [e.g. Ebola and other viral haemorrhagic fevers or Middle East Respiratory Syndrome Coronavirus (MERS-CoV)] suspected, isolate the patient
• Resistance patterns among pathogens vary according to locality (e.g. pneumococcal penicillin resistance in Spain)
• If patient displays features of sepsis/severe sepsis, seek immediate advice from senior colleague and critical care - see Sepsis management guideline

Infection Control alerts

• Check for IC alert
• if IC alert not available, check previous 12 months of microbiology reports
• If MRSA present, treat as tagged for MRSA. See MRSA management
• If ESBL, MGNB, CARB present, treat as tagged for ESBL. See ESBL/MGNB/CARB management

Penicillin Allergy

• True penicillin allergy is rare
• Ask the patient and record what happened when they were given penicillin
• If any doubt about whether patient is truly allergic to penicillin, seek advice from a microbiologist or consultant in infectious diseases

Malaria

• Unless minor upper respiratory tract infection apparent, admit for assessment and exclude falciparum malaria in those who have travelled to endemic areas. Three negative films over 72 hours taken 12-24 hr apart are required to exclude malaria
  • if malaria confirmed contact microbiologist/ID team
• If malaria identified but doubt about type, treat as falciparum especially if patient has returned from a falciparum endemic area

Avian influenza or haemorrhagic fever

• If avian influenza or haemorrhagic fever suspected at time of GP referral or on admission out-of-hours, contact on-call microbiologist 

Typhoid

• If Gram-negative bacilli grown in blood of patient returning from a typhoid endemic area (e.g. Indian sub-continent),
  • if not true penicillin/ceftriaxone allergy, give ceftriaxone 2 g IV by infusion daily
  • if true penicillin/ceftriaxone allergy, contact microbiologist/ID team
  • do not use ciprofloxacin as many strains of Salmonella typhi are resistant
• If typhoid confirmed, contact microbiologist/ID team

Imported fever service

• The imported fever service hosted jointly by Liverpool and London tropical medicine schools can be contacted for further advice - but only after discussion with local microbiology or infectious disease services