Travel infections

Incidence of influenza, dengue and Japanese encephalitis in Australian travellers visiting South and south-eastern Asia

The aim of this study was to estimate the incidence density of influenza, dengue and Japanese encephalitis in Australian travellers to Asia. This study will provide estimates of attack rates for dengue, influenza and Japanese encephalitis in Australian travellers. It will enable both travellers to be informed about their actual risk of disease acquisition from travel and will enable practitioners advising prospective travellers to provide risk data.

Study Coordinator: Dr Irani Ratnam

Collaborators
  • Centre for Travel Medicine, University of Zurich, Switzerland: Patricia Schalgenhauf
  • Monash Infectious DIseases: Alex Padiglione, Ian Woolley
  • Victorian Infectious DIseases Service: Irani Ratnam, Joseph Torresi, Jim Black, Michael Richards, Beverly Ann Biggs, Karin Leder, Tony Gherardin
Publications
Low risk of Japanese encephalitis in short-term Australian travelers to Asia.
Ratnam I, Leder K, Black J, Biggs BA, Matchett E, Padiglione A, Woolley I, Panagiotidis T, Gherardin T, Luxemburger C, Torresi J.
J Travel Med. 2013 May;20(3):206-8. doi: 10.1111/jtm.12019. Epub 2013 Mar 8.
PMID: 23577868 [PubMed - in process]

Incidence and risk factors for acute respiratory illnesses and influenza virus infections in Australian travellers to Asia.
Ratnam I, Black J, Leder K, Biggs BA, Gordon I, Matchett E, Padiglione A, Woolley I, Karapanagiotidis T, Gherardin T, Demont C, Luxemburger C, Torresi J.
J Clin Viriol 2013 Feb 1. pii: S1386-6532(13)00032-2. doi: 10.1016/j.jcv.2013.01.008. [Epub ahead of print]
PMID: 23380660 [PubMed - as supplied by publisher]

Incidence and seroprevalence of dengue virus infections in Australian travellers to Asia.
Ratnam I, Black J, Leder K, Biggs BA, Matchett E, Padiglione A, Woolley I, Panagiotidis T, Gherardin T, Pollissard L, Demont C, Luxemburger C, Torresi J.
Eur J Clin Microbiol Infect Dis. 2011 Oct 9. [Epub ahead of print]
PMID: 21983919 [PubMed - as supplied by publisher]

Presented at the 20th European Congress of Clinical Microbiology and Infectious Diseases Vienna, Austria, 10 - 13 April 2010

Incidence of influenza, dengue and Japanese encephalitis in Australian travellers visiting South and south-eastern Asia
Abstract number: O46
Ratnam I., Black J., Leder K., Biggs B., Richards M., Pollissard L., Luxemburger C., Matchett E., Padaglione A., Woolley I., Schlagenhauf P., Gherardin T., Torresi J.
Objective: To estimate the incidence density of influenza, dengue and Japanese encephalitis (JE) in Australian travellers to Asia.

Methods: Prospective cohort study of Australian travellers to South and South East Asia over a 2 year period. Travellers 16 years of age were recruited from 3 travel clinics, completed validated questionnaires and provided pre and post-travel blood samples for serological testing. Demographic data, destinations and travel patterns, vaccination details and history of flavivirus infection were obtained. Serological testing for dengue IgG by ELISA (Pan-Bio assay), Influenza A and B (complement fixation antibody) and JE (In-house indirect fluorescence antibody) was performed.

Results:Among 450 travellers enrolled, 345 have returned for follow-up, 53 (11.7%) have been lost to follow-up and paired sera have been tested for 324 travellers; 58% were female, median age was 32 years and 24% were born overseas. 72% were short term travellers (<30 days="" and="" main="" traveller="" types="" were="" vacation="" holiday="" goers="" 69="" business="" travellers="" 16="" 76="" reported="" prior="" travel="" to="" asia="" 10="" 8="" 54="" had="" received="" the="" je="" influenza="" vaccines="" respectively="" dengue="" sero-prevalence:="" acute="" seroconversion="" for="" virus="" infection="" was="" demonstrated="" in="" 4="" 324="" 1="" 2="" of="" tested="" this="" translates="" an="" incidence="" 17="" infections="" per="" 000="" 95="" ci="" 7="" a="" further="" 13="" positive="" igg="" indicating="" past="" exposure="" with="" travelled="" china="" n="1)," india="" thailand="" two="" these="" vaccine="" evidence="" recent="" is="" there="" no="" cohort="" div="">

Conclusion: To our knowledge, this is the largest prospective study estimating the incidence of both respiratory and arboviral infections in travellers. For travellers to Asia, the risk of acquiring dengue in an inter-epidemic period is low (incidence density 4.17 infections per 10,000 days of travel). The risk of acquiring influenza in this well vaccinated cohort was equally as low and no JE infections were observed. These findings have important implications for practitioners advising prospective travellers.