, two laboratory-confirmed cases of chikungunya without a travel history were reported on the French part of the Caribbean island of Saint Martin, indicating the start of the first documented outbreak of chikungunya in the Americas. Since this report, the virus spread to several Caribbean islands and French Guiana, and between 6 December 2013 and 27 March 2014 more than 17,000 suspected and confirmed cases have been reported. Further spread and establishment of the disease in the Americas is likely, given the high number of people travelling between the affected and non-affected areas and the widespread occurrence of efficient vectors. Also, the likelihood of the introduction of the virus into Europe from the Americas and subsequent transmission should be considered especially in the context of the next mosquito season in Europe. Clinicians should be aware that, besides dengue, chikungunya should be carefully considered among travellers currently returning from the Caribbean region.

Salmonella enterica serovar Typhi (S. Typhi) is the causative agent of typhoid fever, a systemic human infection with a burden exceeding 20 million cases each year that occurs disproportionately among children in low and middle income countries. Antimicrobial therapy is the mainstay for treatment, but resistance to multiple agents is common. Here we report genotypes and antimicrobial resistance (AMR) determinants detected from routine whole-genome sequencing (WGS) of 533 S. Typhi isolates referred to Public Health England between April 2014 and March 2017, 488 (92%) of which had accompanying patient travel information obtained via an enhanced surveillance questionnaire. The majority of cases involved S. Typhi 4.3.1 (H58) linked with travel to South Asia (59%). Travel to East and West Africa were associated with genotypes 4.3.1 and 3.3.1, respectively. Point mutations in the quinolone resistance determining region (QRDR), associated with reduced susceptibility to fluoroquinolones, were very common (85% of all cases) but the frequency varied significantly by region of travel: 95% in South Asia, 43% in East Africa, 27% in West Africa. QRDR triple mutants, resistant to ciprofloxacin, were restricted to 4.3.1 lineage II and associated with travel to India, accounting for 23% of cases reporting travel to the country. Overall 24% of isolates were MDR, however the frequency varied significantly by region and country of travel: 27% in West Africa, 52% in East Africa, 55% in Pakistan, 24% in Bangladesh, 3% in India. MDR determinants were plasmid-borne (IncHI1 PST2 plasmids) in S. Typhi 3.1.1 linked to West Africa, but in all other regions MDR was chromosomally integrated in 4.3.1 lineage I. We propose that routine WGS data from travel-associated cases in industrialised countries could serve as informal sentinel AMR genomic surveillance data for countries where WGS is not available or routinely performed.

WGS data provided a robust and informative approach for monitoring MDR and emerging resistance to ciprofloxacin in Salmonella Typhi and Salmonella Paratyphi. Phenotypic antimicrobial susceptibility testing continues to be performed to guide targeted individual patient treatment, but inferred AMR profiles from WGS data may be used for surveillance and to guide empirical therapy.

Cyclospora cayetanensis was identified in 176 returned travellers from the Riviera Maya region of Mexico between 1 June and 22 September 2015; 79 in the United Kingdom (UK) and 97 in Canada. UK cases completed a food exposure questionnaire. This increase in reported Cyclospora cases highlights risks of gastrointestinal infections through travelling, limitations in Cyclospora surveillance and the need for improved hygiene in the production of food consumed in holiday resorts.

26Salmonella enterica serovar Typhi (S. Typhi) is the causative agent of typhoid fever, a 27 systemic human infection with a burden exceeding 20 million cases each year that occur 28 disproportionately among children in low and middle income countries. Antimicrobial therapy 29 is the mainstay for treatment, but resistance to multiple agents is common. Here we report 30 genotypes and antimicrobial resistance (AMR) determinants detected from routine whole-31 genome sequencing (WGS) of 533 S. Typhi isolates referred to Public Health England 32 between April 2014 and April 2017, 488 (92%) of which had accompanying patient travel 33 information obtained via an enhanced surveillance questionnaire. The majority of cases 34 involved S. Typhi 4.3.1 (H58) linked with travel to South Asia (58%). Travel to East and West 35Africa were associated with genotypes 4.3.1 and 3.3.1, respectively. Point mutations in the 36 quinolone resistance determining region (QRDR), associated with reduced susceptibility to 37 fluoroquinolones, were very common (85% of all cases) but the frequency varied 38 significantly by region of travel: 95% in South Asia, 43% in East Africa, 27% in West Africa. 39QRDR triple mutants, resistant to ciprofloxacin, were restricted to 4.3.1 lineage II and 40 associated with travel to India, accounting for 23% of cases reporting travel to the country. 41Overall 24% of isolates were MDR, however the frequency varied significantly by region and 42 country of travel: 27% in West Africa, 52% in East Africa, 55% in Pakistan, 24% in 43 Bangladesh, 3% in India. MDR determinants were plasmid-borne (IncHI1 PST2 plasmids) in 44 S. Typhi 3.1.1 linked to West Africa, but in all other regions MDR was chromosomally 45 integrated in 4.3.1 lineage I. We propose that routine WGS data from travel-associated 46 cases in industrialised countries could serve as informal sentinel AMR genomic surveillance 47 data for countries where WGS is not available or routinely performed.48 49 50 3 Author Summary 51 Our data demonstrate how routine WGS data produced by Public Health England can be 52 further mined for informal passive surveillance of Salmonella Typhi circulating in different 53 geographical regions where typhoid is endemic. We have shown the public health utility of a 54 simplified approach to WGS reporting based on the GenoTyphi genotyping framework and 55 nomenclature, which doesn't require the generation of a phylogenetic tree or other 56 phylogenetic analysis. These approaches yielded results consistent with previously reported 57 antimicrobial resistance (AMR) patterns of S. Typhi, including prevalence of multi-drug 58 resistant (MDR) and fluoroquinolone resistance in different regions in association with 59 different pathogen variants. These data provide a rationale and framework for the extraction 60 and reporting of geographically stratified genotype and AMR data from public health labs in 61 non-endemic countries. Prospective analysis and reporting of such data could potentially 62 detect shifts in regional S. Typhi popul...