Impact, health care utilization, and costs of travel-associated mosquito-borne diseases in international travellers: a prospective study.

BACKGROUND: International travellers frequently acquire infectious diseases while travelling, yet relatively little is known about the impact and economic burden of these illnesses on travellers. We conducted a prospective exploratory costing study on adult returning travellers with falciparum malaria, dengue, chikungunya, or Zika virus.

METHODS: Patients were recruited in eight Travel and Tropical Medicine clinics between June 2016 and March 2020 upon travellers' first contact with the health system in their country of residence. The patients were presented with a structured 52-question self-administered questionnaire after full recovery to collect information on patients' healthcare utilization and out-of-pocket costs both in the destination and home country, and about income and other financial losses due to the illness.

RESULTS: A total of 134 patients participated in the study (malaria, 66; dengue, 51; chikungunya, 8; Zika virus, 9; all fully recovered; median age 40; range 18-72 years). Prior to travelling, 42% of patients reported procuring medical evacuation insurance. Across the four illnesses, only 7% of patients were hospitalized abroad compared with 61% at home. Similarly, 15% sought ambulatory services while abroad compared with 61% at home. The average direct out-of-pocket hospitalization cost in the destination country (US$2236; range: $108-$5160) was higher than the direct out-of-pocket ambulatory cost in the destination country (US$327; range: $0-$1560), the direct out-of-pocket hospitalization cost at home (US$35; range: $0-$120), and the direct out-of-pocket ambulatory costs at home (US$45; range: $0-$192). Respondents with dengue or malaria lost a median of USD $570 (IQR 240-1140) and USD $240 (IQR 0-600), respectively, due to their illness, while those with chikungunya and Zika virus lost a median of USD $2400 (IQR 1200-3600) and USD $1500 (IQR 510-2625), respectively.

CONCLUSION: Travellers often incur significant costs due to travel-acquired diseases. Further research into the economic impact of these diseases on travellers should be conducted.