BACKGROUND:Long-term follow-up data on the travel-associated burden of vector-borne diseases (VBDs) are scarce. A prospective multi-site observational study was conducted to delineate the longitudinal course, symptom patterns, physical and mental burden and factors associated with prolonged illness in travellers after four VBDs. METHODS:Patients with confirmed travel-associated acute chikungunya, dengue, Zika or falciparum malaria were recruited at 15 GeoSentinel sites from 2016 to 2021. Persistent signs and symptoms were evaluated at 1, 3, 6, 12 and 18 months (M) post-diagnosis, using a multi-modular study questionnaire with quality of life (QOL) evaluated by 12-item short-form health survey (SF-12). Demographic, premorbid and acute disease characteristics were tested in multivariate analyses to determine factors associated with persistence of symptoms at M3. Missing data were imputed by rules and statistical methods. RESULTS:Among 273 patients enrolled, 35 (13%) had chikungunya, 110 (40%) dengue, 19 (7%) Zika and 109 (40%) falciparum malaria. Median age was 38 years (interquartile range 30-49), 148/273 (54%) were men. At M3, 24/35 (69%) of chikungunya, 27/110 (25%) of dengue, 8/19 (42%) of Zika and 12/109 (11%) of malaria patients had persistent symptoms. The proportion of symptomatic chikungunya patients was 18/35 (51%) at M6, mainly due to musculoskeletal symptoms including arthritis and stiffness. In dengue patients, fatigue and musculoskeletal symptoms without arthritis persisted until 1 year. Zika patients reported persisting headaches, musculoskeletal symptoms including arthritis and fatigue. One month after malaria, fatigue was the main persisting symptom, which resolved almost completely at M3. At M12, 6/35 (17%) of chikungunya, 5/110 (5%) dengue, 3/19 (16%) Zika and only 1/109 (1%) of malaria patients were still symptomatic.Impaired QOL was noted at M3 by 23/35 (66%) of patients with chikungunya, 20/110 (18%) with dengue and 6/19 (32%) with Zika but only 4/109 (4%) with malaria. Female sex, Zika, chikungunya and musculoskeletal symptoms during acute infection were associated with persistent M3 symptoms. CONCLUSIONS:Post-arboviral symptoms and impaired QOL persisted beyond 6 months after chikungunya, dengue and Zika. In contrast, post-malaria fatigue syndrome resolved within 3 months.

In the wake of a large outbreak in Reunion and Mayotte the GeoSentinel network has been signalling chikungunya cases among returning travellers acquired in multiple African and Asian countries between August 1st 2024 and June 10th 2025. These surveillance data suggest a resurgence of chikungunya in the Indian Ocean Region.

In the Indian Ocean Region (IOR), chikungunya virus (CHIKV) outbreaks have surged, driven by climate factors influencing vector ecology and transmission. We analyzed GeoSentinel traveler surveillance data from 2010 to 2024 alongside multiple climate indices representing dominant modes of regional variability, including the Mascarene Subtropical High (MSH), Indian Summer Monsoon, and El Niño Southern Oscillation. Here we identified region-specific associations: in South-Central Asia, chikungunya activity correlated strongly with intensified MSH area during El Niño; in sub-Saharan Africa, links were weaker and influenced by monsoon onset and cross-equatorial flow; in Southeast Asia, outbreaks followed moderate-to-large eastward MSH expansions with lagged effects. These findings suggest that large-scale climate variability modulates chikungunya transmission dynamics across the IOR. Incorporating such climate indicators into early warning systems may enhance outbreak forecasting and guide targeted public health interventions to mitigate chikungunya spread.

Antimalarial drug resistance has become a real public health problem despite WHO measures. New sequencing technologies make it possible to investigate genomic variations associated with resistant phenotypes at the genome-wide scale. Based on the use of hemisynthetic nanopores, the PromethION technology from Oxford Nanopore Technologies can produce long-read sequences, in contrast to previous short-read technologies used as the gold standard to sequence Plasmodium. Two clones of P. falciparum (Pf3D7 and PfW2) were sequenced in long-read using the PromethION sequencer from Oxford Nanopore Technologies without genomic amplification. This made it possible to create a processing analysis pipeline for human Plasmodium with ONT Fastq only. De novo assembly revealed N50 lengths of 18,488 kb and 17,502 kb for the Pf3D7 and PfW2, respectively. The genome size was estimated at 23,235,407 base pairs for the Pf3D7 clone and 21,712,038 base pairs for the PfW2 clone. The average genome coverage depth was estimated at 787X and 653X for the Pf3D7 and PfW2 clones, respectively. This study proposes an assembly processing pipeline for the human Plasmodium genome using software adapted to large ONT data and the high AT percentage of Plasmodium. This search provides all the parameters which were optimized for use with the software selected in the pipeline.

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.

Chikungunya virus, an arthropod-borne pathogen is recognized by the World Health Organization as a top priority Emerging Infectious Disease and is ranked fourth in public health needs according to the Coalition for Epidemic Preparedness Innovations. Despite its substantial impact, as evidenced by an annual estimate of 120 274 disability-adjusted life years, our understanding of the chronic aspects of chikungunya disease remains limited. This review focuses on chronic chikungunya disease, emphasizing its clinical manifestations, immunopathogenesis, therapeutic options and disease burden.

We report a late dihydroartemisinin–piperaquine treatment failure of uncomplicated Plasmodium falciparum malaria infection in a traveller without evidence of drug resistance. The correct treatment intake was confirmed, isolates drugs susceptibility was confirmed by RSA-PSA and chemosusceptibility. No molecular markers associated with resistance to artemisinin derivatives or piperaquine were identified.

The risk of dengue emergence in France this summer is likely and must be considered in preparedness planning. The risk could arise from international visitors but also French travellers returning from epidemic areas. The French preparedness and response plan and the importance of international surveillance after the Olympics are highlighted.

Dihydroartemisinin (or artenimol)–piperaquine is one of the six artemisinin-based combination therapies recommended in uncomplicated malaria treatment. However, artemisinin partial resistance has been reported in Cambodia, Laos, Vietnam, India, and, recently, in Africa. Polymorphisms in the Pfk13 gene have been described as molecular markers of artemisinin resistance and the amplification of the plasmepsine II/III (Pfpmp2/Pfpmp3) gene has been associated with piperaquine resistance. However, some therapeutic failures with this combination remain unexplained by strains’ characterization. We provide an overview on the use of dihydroartemisinin–piperaquine in malaria treatment and discuss tools available to monitor its efficacy.

A French expatriate in Ethiopia presented with severe Plasmodium falciparum infection. The blood smear was remarkable associating multiple stages of parasites including circulating schizonts with a high rate of intraleukocytic malaria pigments. Under artesunate treatment, without polymorphism in PfK13 gene, delayed clearance of parasites occurred, probably following the massive merogony.

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.

BACKGROUND Antibiotics are growth promotors used in animal farming. Doxycycline (DOXY) is a tetracycline antibiotic taken daily and continued 1 month after return to protect against malaria during travel and deployment in endemic areas. We evaluated DOXY impact on body weight in military international travelers. MATERIEL AND METHODS A prospective cohort analysis was conducted in 2016-2018, recruiting 170 French soldiers before a 4-month assignment overseas. Many clinical data including anthropometric measures by an investigator were collected before and after deployment. Weight gain was defined by an increase of 2% from baseline. The study protocol was supported by the French Armed Forces Health Services and approved by the French ethics committee (IRB no. 2015-A01961-48, ref promoter 2015RC0). Written, informed consent was obtained with signature from each volunteer before inclusion. RESULTS After deployment, 84 soldiers were followed up. Overall, 38/84 (45%) were deployed to Mali with DOXY malaria prophylaxis, and others were deployed to Iraq or Lebanon without malaria prophylaxis according to international recommendations. Body weight increased in 24/84 (30%), of whom 14/24 (58%) were exposed to DOXY. In bivariate analysis, DOXY had a positive but not significant effect on weight gain (P-value = .4). In the final logistic regression model (Fig. 3), weight gain after deployment positively correlated with an increase in waist circumference (odds ratio [OR] 1.23 with 95% CI [1.06-1.47]) suggesting fat gain; with sedentary work (OR 5.34; 95% CI [1.07-31.90]); and with probiotic intake (OR 5.27; 95% CI [1.51-20.40]). Weight impact of probiotics was more important when associated with DOXY intake (OR 6.86; 95% CI [1.52-38.1]; P-value = .016). CONCLUSIONS Doxycycline (DOXY) malaria prophylaxis during several months did not cause significant weight gain in soldiers. Further studies are required in older and less sportive traveling populations, and to investigate a cumulative effect over time and recurrent DOXY exposure. Doxycycline (DOXY) may enhance other growth-promoting factors including fatty food, sedentariness, and strain-specific probiotics contained in fermented dairy products which are also used as growth promotors.

Increasing numbers of travellers returning from Cuba with dengue virus infection were reported to the GeoSentinel Network from June to September 2022, reflecting an ongoing local outbreak. This report demonstrates the importance of travellers as sentinels of arboviral outbreaks and highlights the need for early identification of travel-related dengue.

During 2019-2020, a chikungunya outbreak occurred in Djibouti City, Djibouti, while dengue virus and malar-ia parasites were cocirculating. We used blotting paper to detect arbovirus emergence and confirm that it is a robust method for detecting and monitoring arbovirus outbreaks remotely.

The human monkeypox disease has mainly been described in Western and Central Africa. Since May 2022, the monkeypox virus has been spreading worldwide in a new epidemiological pattern, where cases result from person-to-person transmission, and develop clinically milder or less typical illness than during previous out-breaks in endemic areas. The newly-emerging monkeypox disease needs to be described over the long term, to improve cases definitions, to implement prompt control measures against epidemics, and to provide supportive care. Hence, we first conducted a review of historical and recent outbreaks to define the full clinical spectrum of the monkeypox disease and its course known so far. Then, we built a self-administrated questionnaire collecting daily symptoms of the monkeypox infection to follow cases and their contacts, even remotely. This tool will assist in the management of cases, the surveillance of contacts, and the conduct of clinical studies.