Dengue is a leading cause of febrile illness among international travellers. We aimed to describe the epidemiology and clinical characteristics of imported dengue in returning travellers evaluated at GeoSentinel sites from 2007 to 2022. We retrieved GeoSentinel records of dengue among travellers residing in non-endemic countries. We considered dengue confirmed when diagnosed by a positive dengue virus (DENV)–specific reverse-transcriptase polymerase chain reaction, positive NS-1 antigen and/or anti-DENV IgG seroconversion, and probable when diagnosed by single anti-DENV IgM or high-titre anti-DENV IgG detection. Severe dengue was defined as evidence of clinically significant plasma leakage or bleeding, organ failure, or shock, according to the 2009 World Health Organization guidance. Complicated dengue was defined as either severe dengue or dengue with presence of any warning sign. Analyses were descriptive. This analysis included 5958 travellers with confirmed (n = 4859; 81.6%) or probable (n = 1099; 18.4%) dengue. The median age was 33 years (range: <1–91); 3007 (50.5%) travellers were female. The median travel duration was 21 days (interquartile range [IQR]: 15–32). The median time between illness onset and GeoSentinel site visit was 7 days (IQR: 4–15). The most frequent reasons for travel were tourism (67.3%), visiting friends or relatives (12.2%) and business (11.0%). The most frequent regions of acquisition were South East Asia (50.4%), South Central Asia (14.9%), the Caribbean (10.9%) and South America (9.2%). Ninety-five (1.6%) travellers had complicated dengue, of whom 27 (0.5%) had severe dengue and one died. Of 2710 travellers with data available, 724 (26.7%) were hospitalized. The largest number of cases (n = 835) was reported in 2019. A broad range of international travellers should be aware of the risk of acquiring dengue and receive appropriate pre-travel counselling regarding preventive measures. Prospective cohort studies are needed to further elucidate dengue risk by destination and over time, as well as severe outcomes and prolonged morbidity (long dengue) due to travel-related dengue.

Objective To determine whether live-attenuated yellow fever vaccine (YFV) was associated with MS relapse, we evaluated the clinical courses of 23 patients in the year before and the year after immunization at the university hospital of Geneva, Switzerland. Methods This self-controlled retrospective cohort included adult patients with MS receiving YFV between 2014 and 2018 and defined the year before vaccination, the 3 months thereafter, and the 9 months following as the pre-exposure (PEP), exposure-risk (ERP), and postrisk (PRP) periods, respectively. The primary outcome was the relative incidence of relapse in the ERP vs the PEP. Secondary end points included the presence of new T2-weighted (T2) or T1-weighted gadolinium-positive (T1Gd+) MRI lesions. Results Of 23 patients with MS receiving YFV (20 relapsing MS and 3 primary progressive MS), 17 (74%) were women; mean age was 34 years (SD ±10); and 10 of 23 (40%) were treated with disease-modifying therapies (DMTs). Although 9 patients experienced 12 relapses in the PEP, only one experienced a relapse in the ERP; 3 other patients experienced one relapse each in the PRP. None of the 8 patients receiving natalizumab at the time of vaccination experienced relapse thereafter. In the PEP, ERP, and PRP, 18, 2, and 9 patients had new brain and/or spinal cord lesions on T2 or T1Gd + MRI, respectively. Conclusions In this cohort, YF vaccination was associated with neither an increase in MS relapse nor emergence of brain and/or spinal lesions. Further studies are warranted to confirm these findings. Classification of evidence This study provides Class IV evidence that for persons with MS, YFV may not increase relapse risk.

Dengue virus is a flavivirus transmitted by Aedes mosquitoes and is an important cause of illness worldwide. Data on the severity of travel-associated dengue illness are limited. To describe the epidemiology, clinical characteristics, and outcomes among international travelers with severe dengue or dengue with warning signs as defined by the 2009 World Health Organization classification (that is, complicated dengue). Retrospective chart review and analysis of travelers with complicated dengue reported to GeoSentinel from January 2007 through July 2022. 20 of 71 international GeoSentinel sites. Returning travelers with complicated dengue. Routinely collected surveillance data plus chart review with abstraction of clinical information using predefined grading criteria to characterize the manifestations of complicated dengue. Of 5958 patients with dengue, 95 (2%) had complicated dengue. Eighty-six (91%) patients had a supplemental questionnaire completed. Eighty-five of 86 (99%) patients had warning signs, and 27 (31%) were classified as severe. Median age was 34 years (range, 8 to 91 years); 48 (56%) were female. Patients acquired dengue most frequently in the Caribbean (n = 27 [31%]) and Southeast Asia (n = 21 [24%]). Frequent reasons for travel were tourism (46%) and visiting friends and relatives (32%). Twenty-one of 84 (25%) patients had comorbidities. Seventy-eight (91%) patients were hospitalized. One patient died of nondengue-related illnesses. Common laboratory findings and signs were thrombocytopenia (78%), elevated aminotransferase (62%), bleeding (52%), and plasma leakage (20%). Among severe cases, ophthalmologic pathology (n = 3), severe liver disease (n = 3), myocarditis (n = 2), and neurologic symptoms (n = 2) were reported. Of 44 patients with serologic data, 32 confirmed cases were classified as primary dengue (IgM+/IgG-) and 12 as secondary (IgM-/IgG+) dengue. Data for some variables could not be retrieved by chart review for some patients. The generalizability of our observations may be limited. Complicated dengue is relatively rare in travelers. Clinicians should monitor patients with dengue closely for warning signs that may indicate progression to severe disease. Risk factors for developing complications of dengue in travelers need further prospective study. Centers for Disease Control and Prevention, International Society of Travel Medicine, Public Health Agency of Canada, and GeoSentinel Foundation.

Blastocystis sp. is a worldwide-distributed protist colonizing the guts of humans and a great variety of animals. It is unclear whether it is just a commensal or an infectious parasite that prompts eradication. The main objective of this study was to evaluate the usefulness of metronidazole in patients with gastrointestinal symptoms harbouring only Blastocystis sp. In addition, we explored whether Blastocystis subtype or concomitant parasitic infection detected by polymerase chain reaction (PCR) may influence treatment outcome. We included adults with persistent gastrointestinal symptoms (>14 days) visiting a primary care physician and in whom stool microscopy revealed only Blastocystis sp. Eligible patients were randomized to receive ten days of metronidazole or placebo, followed by a crossover if still symptomatic. The primary outcome was normal stool consistency. Secondary outcomes were the changes in other abdominal symptoms (bloating, flatulence, abdominal pain, number of daily bowel movements) and general wellbeing. After the clinical phase of the study, Blastocystis subtypes were determined by PCR sequencing and stool samples were tested for 11 other protozoa with an in-house PCR. We screened 581 outpatients for inclusion, of which 50 met the eligibility criteria. There was no difference in the primary outcome, nor any of the secondary outcomes between the subjects treated with metronidazole and placebo. The most frequent Blastocystis subtypes were ST4 (11/36) and ST2 (10/36). The in-house PCR was positive for other protozoa in 25% (10/40) of the patients. We identified Dientamoeba fragilis in 5, Entamoeba dispar in 3 and Cyclospora cayetanensis in 2 patients. Stratified analysis according to Blastocystis subtype or the presence of other protozoa showed no significant difference in treatment outcome with metronidazole or placebo. Among patients infected with Blastocystis sp., metronidazole, compared with placebo, was not better in improving gastrointestinal symptoms, irrespective of subtype or microscopically undetected coinfection with other protozoa.

Strongyloides stercoralis, causative agent of a neglected tropical disease, is a soil-transmitted helminth which may cause lifelong persisting infection due to continuous autoinfection. In the case of immunosuppression, life-threatening hyperinfection and disseminated strongyloidiasis can develop. We propose a pragmatic screening algorithm for latent strongyloidiasis based on epidemiologic exposure and immunosuppression status that can be applied for any kind of immunosuppressive therapy. The algorithm allows the diagnosis of latent strongyloidiasis with optimal accuracy in a well-equipped setting, while for endemic settings where the complete testing array is unavailable, an empiric treatment is generally recommended. Accurate diagnosis and extensive empiric treatment will both contribute to decreasing the current neglect of strongyloidiasis.

Rothia dentocariosa is part of the normal human oropharyngeal microflora and is frequently associated with dental caries and periodontal disease. Invasive disease has been described essentially in immunocompromised hosts and/or patients with underlying conditions as predisposing factors. We present a case of an otherwise healthy 46-years old male with spondylodiscitis caused by this pathogen. Treatment with ceftriaxone and rifampin was successful. To our knowledge, this is the first R. dentocariosa spondylodiscitis reported in an immunocompetent patient, and the second one in the literature overall.