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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. [ABSTRACT FROM AUTHOR]

Background Chikungunya is an important travel-related disease because of its rapid geographical expansion and potential for prolonged morbidity. Improved understanding of the epidemiology of travel-related chikungunya infections may influence prevention strategies including education and vaccination. Methods We analysed data from travellers with confirmed or probable chikungunya reported to GeoSentinel sites from 2005 to 2020. Confirmed chikungunya was defined as a compatible clinical history plus either virus isolation, positive nucleic acid test or seroconversion/rising titre in paired sera. Probable chikungunya was defined as a compatible clinical history with a single positive serology result. Results 1202 travellers (896 confirmed and 306 probable) with chikungunya were included. The median age was 43 years (range 0–91; interquartile range [IQR]: 31–55); 707 (58.8%) travellers were female. Most infections were acquired in the Caribbean (28.8%), Southeast Asia (22.8%), South Central Asia (14.2%) and South America (14.2%). The highest numbers of chikungunya cases reported to GeoSentinel were in 2014 (28.3%), 2015 (14.3%) and 2019 (11.9%). The most frequent reasons for travel were tourism (n  = 592; 49.3%) and visiting friends or relatives (n  = 334; 27.7%). The median time to presentation to a GeoSentinel site was 23 days (IQR: 7–52) after symptom onset. In travellers with confirmed chikungunya and no other reported illnesses, the most frequently reported symptoms included musculoskeletal symptoms (98.8%), fever/chills/sweats (68.7%) and dermatologic symptoms (35.5%). Among 917 travellers with information available, 296 (32.3%) had a pretravel consultation. Conclusions Chikungunya was acquired by international travellers in almost 100 destinations globally. Vector precautions and vaccination where recommended should be integrated into pretravel visits for travellers going to areas with chikungunya or areas with the potential for transmission. Continued surveillance of travel-related chikungunya may help public health officials and clinicians limit the transmission of this potentially debilitating disease by defining regions where protective measures (e.g. pretravel vaccination) should be strongly considered. [ABSTRACT FROM AUTHOR]

The article discusses the growing concern of arboviral diseases such as dengue and chikungunya in travelers. The United States has recently approved the world's first chikungunya vaccine, which has shown promising results in terms of seroresponse and clinical benefit. The article also highlights the increasing incidence of dengue in travelers and the availability of a new dengue vaccine. The recommendations for the use of these vaccines vary among different expert groups, but the authors argue for broader recommendations to address the high burden of these diseases. Further research is needed to gather more data on the vaccines' effectiveness, safety, and duration of protection. [Extracted from the article]

Background Infectious disease epidemiology is continuously shifting. While travel has been disrupted by the COVID-19 pandemic and travel-related epidemiological research experienced a pause, further shifts in vaccine-preventable diseases (VPDs) relevant for travellers have occurred. Methods We conducted a literature search on the epidemiology of travel-related VPD and synthesized data for each disease with a focus on symptomatic cases and on the impact of the respective infection among travellers, considering the hospitalization rate, disease sequela and case fatality rate. We present new data and revised best estimates on the burden of VPD relevant for decisions on priorities in travel vaccines. Results COVID-19 has emerged to be a top travel-related risk and influenza remains high in the ranking with an estimated incidence at 1% per month of travel. Dengue is another commonly encountered infection among international travellers with estimated monthly incidence of 0.5–0.8% among non-immune exposed travellers; the hospitalized proportion was 10 and 22%, respectively, according to two recent publications. With recent yellow fever outbreaks particularly in Brazil, its estimated monthly incidence has risen to >0.1%. Meanwhile, improvements in hygiene and sanitation have led to some decrease in foodborne illnesses; however, hepatitis A monthly incidence remains substantial in most developing regions (0.001–0.01%) and typhoid remains particularly high in South Asia (>0.01%). Mpox, a newly emerged disease that demonstrated worldwide spread through mass gathering and travel, cannot be quantified regarding its travel-related risk. Conclusion The data summarized may provide a tool for travel health professionals to prioritize preventive strategies for their clients against VPD. Updated assessments on incidence and impact are ever more important since new vaccines with travel indications (e.g. dengue) have been licensed or are undergoing regulatory review. [ABSTRACT FROM AUTHOR]

Background International travellers frequently acquire infectious diseases whilst 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 whilst abroad compared with 61% at home. The average direct out-of-pocket hospitalization cost in the destination country (USD $2236; range: $108–$5160) was higher than the direct out-of-pocket ambulatory cost in the destination country (USD $327; range: $0–$1560), the direct out-of-pocket hospitalization cost at home (USD $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 (Interquartile range [IQR] 240–1140) and USD $240 (IQR 0–600), respectively, due to their illness, whilst 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. [ABSTRACT FROM AUTHOR]

Rationale For Review: Giardiasis is one of the most common human protozoal infections worldwide. First-line therapy of giardiasis includes nitroimidazole antibiotics. However, treatment failure with nitroimidazoles is increasingly reported, with up to 45% of patients not responding to initial treatment. There is no clear consensus on the approach to the management of nitroimidazole-refractory giardiasis. This systematic review aims to summarize the literature on pharmacotherapy for nitroimidazole-refractory giardiasis.Methods: We conducted a systematic review of the literature to determine the optimal management strategies for nitroimidazole-refractory giardiasis. We searched Pubmed/MEDLINE, Embase and Cochrane library using the following search terms 'Giardia' AND 'treatment failure' OR 'refractory giardia' OR 'resistant giardia' with date limits of 1 January 1970 to 30 June 2021. We included all reports on humans, which described clinical outcomes of individuals with treatment refractory giardiasis, including case series and case reports. A descriptive synthesis of the data was conducted with pooling of data for interventions.Key Findings: Included in this review were five prospective studies, three retrospective studies, seven case series and nine case reports. Across these reports, a wide heterogeneity of treatment regimens was employed, including retreatment with an alternative nitroimidazole, combination therapy with a nitroimidazole and another agent and monotherapy with non-nitroimidazole regimens, including quinacrine, paromomycin and nitazoxanide. Retreatment with a nitroimidazole was not an effective therapy for refractory giardiasis. However, treatment with a nitroimidazole in combination with albendazole had a cure rate of 66.9%. In the included studies, quinacrine monotherapy was administered to a total of 179 patients, with a clinical cure rate of 88.8%. Overall, quinacrine was fairly well tolerated.Conclusions: Reports on the treatment of nitroimidazole-refractory giardiasis demonstrate a heterogeneous approach to treatment. Of these, quinacrine appeared to be highly effective, though more data on its safety are needed. [ABSTRACT FROM AUTHOR]

Background: Human coexistence with other animals can result in both intentional and unintentional contact with a variety of mammalian and non-mammalian species. International travellers are at risk for such encounters; travellers risk injury, infection and possibly death from domestic and wild animal bites, scratches, licks and other exposures. The aim of the present analysis was to understand the diversity and distribution of animal-related exposures among international travellers.Methods: Data from January 2007 through December 2018 from the GeoSentinel Surveillance Network were reviewed. Records were included if the exposure was non-migration travel with a diagnosis of an animal (dog, cat, monkey, snake or other) bite or other exposure (non-bite); records were excluded if the region of exposure was not ascertainable or if another, unrelated acute diagnosis was reported.Results: A total of 6470 animal exposures (bite or non-bite) were included. The majority (71%) occurred in Asia. Travellers to 167 countries had at least one report of an animal bite or non-bite exposure. The majority (76%) involved dogs, monkeys and cats, although a wide range of wild and domestic species were involved. Almost two-thirds (62.6%) of 4395 travellers with information available did not report a pretravel consultation with a healthcare provider.Conclusions: Minimizing bites and other animal exposures requires education (particularly during pretravel consultations) and behavioral modification. These should be supplemented by the use of pre-exposure rabies vaccination for travellers to high-risk countries (especially to those with limited access to rabies immunoglobulin), as well as encouragement of timely (in-country) post-exposure prophylaxis for rabies and Macacine alphaherpesvirus 1 (herpesvirus B) when warranted. [ABSTRACT FROM AUTHOR]