Encephalitis in travellers: a prospective multicentre study
Authors: Picard Léa , Mailles Alexandra , Fillâtre Pierre , Tattevin Pierre , Stahl Jean-Paul ,   the ENCEIF scientific committee, Abgrall Sophie , Argaud Laurent , Argemi Xavier , Asseray Nathalie , Baille Guillaume , Baldolli Aurélie , Benghanem Sarah , Biberon Julien , Biron Charlotte , Blanchet-Fourcade Geneviève , Blot Mathieu , Bonnetain Anne , Botelho-Nevers Elisabeth , Bourdain Frédéric , Boutoille David , Brasme Hélène , Bruel Cédric , Bruneel Fabrice , Buzele Rodolphe , Canouï Etienne , Casenave Philippe , Castan Bernard , Cazanave Charles , Cazorla Céline , Challan-Belval Thibault , Chavanet Pascal , Chirouze Catherine , Chroboczek Tomasz , Courjon Johan , De Broucker Thomas , De La Blanchardière Arnaud , de Montmollin Etienne , Degroote Thècle , Delaroche Marine , Denes Eric , Deschanvres Colin , Diard-Detoeuf Capucine , Dinh Aurélien , Epaulard Olivier , Fillatre Pierre , Forestier Emmanuel , Fraisse Thibault , Froidure Marie , Gaborit Benjamin , Gagneux-Brunon Amandine , Gaillard Nicolas , Galbois Arnaud , Godement Mathieu , Goehringer François , Gravier Simon , Greigert Valentin , Gueit Isabelle , Guimard Thomas , Henry Carole , Hentzien Maxime , Herbrecht Jean-Etienne , Jaquet Pierre , Jommier Fanny , Katchatourian Lydie , Kerneis Solene , Krause Jessica , Le Cam Manuela , Le Maréchal Marion , Le Moal Gwenael , Le Turnier Paul , Lecomte Raphael , Lecompte Anne-Sophie , Lefaucheur Romain , Lejeune Stéphanie , Lescure Xavier , Lesieur Olivier , Lesprit Philippe , Louis Guillaume , Lucas Christelle , Mahieu Rafael , Makinson Alain , Marc Guillaune , Maria Alexandre , Marin Nathalie , Martin Aurélie , Martin-Blondel Guillaume , Martinot Martin , Mas Alexandre , Mateu Philippe , Matt Morgan , Maulin Laurence , Mechai Frédéric , Mutez Eugénie , Orain Jérémie , Schieber-Pachart Anne , Pansu Nathalie , Patrat-Delon Solene , Pavese Patricia , Pelerin Hélène , Pelonde-Erimée Véronique , Pierre Isabelle , Ponscarme Diane , Psimaras Dimitri , Puges Mathilde , Reveillon-Istin Mathilde , Rheims Sylvain , Richard-Mornas Aurélie , Riché Agnès , Roubeau Vincent , Ruch Yvon , Runge Isabelle , Savini Hélène , Sonneville Romain , Stahl Jean-Paul , Tattevin Pierre , Tiercelet Kelly , Touati Saber , Turmel Jean-Marie , Tyvaert Isabelle , Vareil Marc-Olivier , Vidal-Roux Magalie , Vitrat Virginie , Wang Adrien , Wille Heidi , Zuber Mathieu ,   investigators group, Almoyna-Martinez Laurent , Bouchaud Olivier , de Broucker Thomas , Bruneel Fabrice , Castan Bernard , Denes Eric , Epaulard Olivier , Girard Nadine , Herrmann Jean-Louis , Honnorat Jérome , Mailles Alexandra , Morand Patrice , Raffi François , Roblot France , Stahl Jean-Paul , Sonneville Romain , Tattevin Pierre 
Published: December 2022

Background

As the epidemiology of encephalitis varies from one country to another, international travel may be an important clue for the diagnostic workout of this puzzling disease.

Methods

We performed an ancillary study using the ENCEIF prospective cohort conducted in 62 clinical sites in France from 2016 to 2019. All cases of encephalitis in adults that fulfilled a case definition derived from the International Encephalitis Consortium were included. Travellers were defined as patients who spent at least one night in a foreign country within the last six months.

Results

Of the 494 encephalitis patients enrolled, 69 (14%) were travellers. As compared to non-travellers, they were younger (median age, 48 years [interquartile range, 36–69] vs 66 [49–76], P &lt; 0.001), less likely to be immunocompromised: 2/69 (3%) vs 56/425 (13%), P = 0.02, and reported more arthralgia: 7/69 (10%) vs 11/425 (3%), P = 0.007. The risk of poor outcome at hospital discharge (Glasgow outcome scale ≤3), was similar for travellers and for non-travellers after adjustment (aOR 0.80 [0.36–1.80], P = 0.594). Arboviruses were the main causes of encephalitis in travellers: 15/69 (22%) vs 20/425 (5%) in non-travellers, P &lt; 0.001, and Herpes simplex virus (HSV) was the second (9/69, 13%). Of note, in 19% (13/69) of cases, the risk of encephalitis in travellers may have been decreased with a vaccine.

Conclusion

The two primary causes of encephalitis in travellers are arboviruses and HSV. Empirical treatment of encephalitis in travellers must include acyclovir. Pre-travel advice and vaccination may decrease the risk of encephalitis in travellers.