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. 2024 Jun 3;31(4):taae010.
doi: 10.1093/jtm/taae010.

Intestinal protozoa in returning travellers: a GeoSentinel analysis from 2007 to 2019

Thomas Weitzel  1   2 , Ashley Brown  3 , Michael Libman  4 , Cecilia Perret  5 , Ralph Huits  6 , Lin Chen  7 , Daniel T Leung  8 , Karin Leder  9 , Bradley A Connor  10 , Marta D Menéndez  11 , Hilmir Asgeirsson  12   13 , Eli Schwartz  14   15 , Fernando Salvador  16   17 , Denis Malvy  18 , Mauro Saio  19 , Francesca F Norman  20   21 , Bhawana Amatya  22 , Alexandre Duvignaud  18 , Stephen Vaughan  23 , Marielle Glynn  3 ; GeoSentinel Network; Kristina M Angelo  3
Collaborators, Affiliations

Intestinal protozoa in returning travellers: a GeoSentinel analysis from 2007 to 2019

Thomas Weitzel et al. J Travel Med. .

Abstract

Background: Prolonged diarrhoea is common amongst returning travellers and is often caused by intestinal protozoa. However, the epidemiology of travel-associated illness caused by protozoal pathogens is not well described.

Methods: We analysed records of returning international travellers with illness caused by Giardia duodenalis, Cryptosporidium spp., Cyclospora cayetanensis or Cystoisospora belli, reported to the GeoSentinel Network during January 2007-December 2019. We excluded records of travellers migrating, with an unascertainable exposure country, or from GeoSentinel sites that were not located in high-income countries.

Results: There were 2517 cases, 82.3% giardiasis (n = 2072), 11.4% cryptosporidiosis (n = 287), 6.0% cyclosporiasis (n = 150) and 0.3% cystoisosporiasis (n = 8). Overall, most travellers were tourists (64.4%) on long trips (median durations: 18-30 days). Cryptosporidiosis more frequently affected people < 18 years (13.9%) and cyclosporiasis affected people ≥ 40 years (59.4%). Giardiasis was most frequently acquired in South Central Asia (45.8%) and sub-Saharan Africa (22.6%), cryptosporidiosis in sub-Saharan Africa (24.7%) and South-Central Asia (19.5%), cyclosporiasis in South East Asia (31.3%) and Central America (27.3%), and cystoisosporiasis in sub-Saharan Africa (62.5%). Cyclosporiasis cases were reported from countries of uncertain endemicity (e.g. Cambodia) or in countries with no previous evidence of this parasite (e.g. French Guiana). The time from symptom onset to presentation at a GeoSentinel site was the longest amongst travellers with giardiasis (median: 30 days). Over 14% of travellers with cryptosporidiosis were hospitalized.

Conclusions: This analysis provides new insights into the epidemiology and clinical significance of four intestinal protozoa that can cause morbidity in international travellers. These data might help optimize pretravel advice and post-travel management of patients with travel-associated prolonged gastrointestinal illnesses. This analysis reinforces the importance of international travel-related surveillance to identify sentinel cases and areas where protozoal infections might be undetected or underreported.

Keywords: Cryptosporidium; Cyclospora; Giardia; Travel; gastrointestinal diseases; surveillance.

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Conflict of interest statement

Conflict of interest

M.L. and R.H. receive salary support from GeoSentinel, Cooperative Agreement between the US Centers for Disease Control and Prevention and the International Society of Travel Medicine. All remaining authors declare that they have no conflicts of interest.

Figures

Figure 1
Figure 1
Annual case numbers of travel-associated giardiasis, cryptosporidiosis, cyclosporiasis and cystoisosporiasis reported to GeoSentinel, 2007–19 (N = 2517).
Figure 2
Figure 2
Heat map of regions where travellers acquired giardiasis, cryptosporidiosis, cyclosporiasis and cystoisosporiasis reported to GeoSentinel, 2007–19 (N = 2517). Numbers represent relative frequencies (%) of protozoal parasites in each region.
Figure 3
Figure 3
Countries where travel-associated infections with intestinal protozoa were acquired (relative frequency) reported to GeoSentinel, 2007–19 (N = 2517).
Figure 4
Figure 4
Percentage of diagnostic methods applied to diagnose protozoal infections by year reported to GeoSentinel, 2007–19 (N = 1224).
See this image and copyright information in PMC

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