Travel-acquired infection	Diagnostic test(s)
Malaria	1. Thick and thin blood smears ± antigen-based dipstick assay; minimum 2-3 times over 24-48 hours 2. Blood for malaria polymerase chain reaction (PCR) if smears and/or dipstick negative but index of suspicion high
Acute travellers’ diarrhea / gastroenteritis (60-80% bacterial)	1. Stool culture for enteropathogens x 1 (will detect Salmonella, Shigella, Campylobacter, E. coli O157:H7, and often Yersinia) 2. Stool for Clostridium difficile toxin 3. Stool for ova and parasites (O&P) x 3 (be aware that not all laboratories screen for all protozoa, including coccidia, routinely; check with local laboratory for special staining request requirements) 4. Amoebic serology ± stool Entamoeba histolytica ELISA if bloody stool
RTI	1. Chest x-ray 2. Nasopharyngeal swab (NP) swab for viral antigen testing or PCR (influenza A/B, respiratory syncytial virus [RSV], adenovirus, parainfluenza virus 1-3, human metapneumovirus, coronavirus) 3. Sputum for culture and susceptibility (C&S) and acid-fast bacilli (AFB) (as directed by index of suspicion) 4. Legionella urine antigen 5. Epstein-Barr virus (EBV) – EBV monospot unreliable in children ≤ 4 years of age; EBV viral capsule antigen (VCA) IgM/IgG, EBV nuclear antigen (EBNA) IgM/IgG 6. (Serology for Q-fever, Histoplasma, Blastomyces, Coccidioides as directed by index of suspicion and travel exposures; urinary antigen for Histoplasma)
Dengue	1. Acute and convalescent sera (2 weeks after) for dengue IgM and IgG
Enteric fever due to Salmonella enterica serovar Typhi or Paratyphi	1. Blood culture x 2 (caution if the patient has received antibiotics as they may have negative blood cultures) 2. Stool culture 3. (Bone marrow aspirate and culture)
Skin and soft tissue infection	1. Clinical diagnosis 2. Skin swab for methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) if exudative 3. If ulcerative, smears for Giemsa-stain, biopsy or aspirate for Leishmania culture or PCR; consider skin swab to rule out ecthyma ulcer due to Staphylococcus or Pseudomonas
Rickettsioses	1. Clinical diagnosis – presence of an eschar is diagnostic (but may not be present) 2. Acute and convalescent sera for rickettsial serology
Acute UTI / STI	1. Urinalysis and urine microscopy 2. Urine culture 3. Urine and/or endocervical swabs for GC/CT 4. Swab for viral PCR of genital vesicles 5. Blood for HIV, HBV, HCV and syphilis serology
Viral hepatitis	1. HAV – HAV IgM, HAV IgG (unless history of previous vaccination) 2. HBV – HBsAg (surface antigen), HBsAb (surface antibody), HBcAb (core antibody), HBeAg (e antigen), HBeAb (e antibody); HBV DNA 3. HCV – HCV total antibody 4. Hepatitis D virus (HDV) – Anti-HDV antigen; serum HDV RNA reverse transcription PCR (RT-PCR) 5. Hepatitis E virus (HEV) – Anti-HEV IgM antibody; blood or stool for HEV PCR 6. EBV – EBV monospot unreliable in children ≤ 4 years of age; EBV VCA IgM/IgG, EBNA IgM/IgG 7. Cytomegalovirus (CMV) – IgM/IgG; CMV antigenemia; serum for CMV PCR
Other potentially travel-acquired infections diagnosed by serology	1. Viral – Chikungunya, arboviruses 2. Bacterial – Q-fever, Brucella (can also be cultured from blood or bone marrow), Leptospira 3. Fungal – Histoplasma, Blastomyces, Coccidioides, Cryptococcus (can detect by serum or CSF or urinary antigen also) 4. Parasitic – Strongyloides, Schistosoma, Amoebiasis (can also detect in stool O&P and by stool ELISA)