Epidemiology and Infection最新文献

Climate conditions are known to modulate infectious disease transmission, yet their impact on measles transmission remains underexplored. In this study, we investigate the extent to which climate conditions modulate measles transmission, utilizing measles incidence data during 2005-2008 from China. Three climate-forced models were employed: a sinusoidal function, an absolute humidity (AH)-forced model, and an AH and temperature (AH/T)-forced model. These models were integrated into an inference framework consisting of a susceptible-exposed-infectious-recovered (SEIR) model and an iterated filter (IF2) to estimate epidemiological characteristics and assess climate influences on measles transmission. During the study period, measles epidemics peaked in spring in northern China and were more diverse in the south. Our analyses showed that the AH/T model better captured measles epidemic dynamics in northern China, suggesting a combined impact of humidity and temperature on measles transmission. Furthermore, we preliminarily examined the impact of other factors and found that population susceptibility and incidence rate were both positively correlated with migrant worker influx, suggesting that higher susceptibility among migrant workers may sustain measles transmission. Taken together, our study supports a role of humidity and temperature in modulating measles transmission and identifies additional factors in shaping measles epidemic dynamics in China.

Salmonella Typhimurium sequence type (ST) 36 is a rare sequence type in Sweden. During August-November 2024, 100 cases of Salmonella Typhimurium ST36 were reported nationwide. The highest proportions of cases were observed among individuals aged 0-10 years (17%) and 41-50 years (20%), with females representing 65% of the total cases. Microbiological analysis of the S. Typhimurium ST36 isolates identified nine clusters and five individual strains clustering within 53 single-nucleotide polymorphisms. A matched case-control study found cases to be associated with the consumption of alfalfa sprouts (adjusted odds ratio = 8.94, 95% CI: 2.96-27.1). Trace-back investigation identified seeds used by two alfalfa sprout producers in Sweden as the likely source of the outbreak, although microbiological analysis of sprouted alfalfa seeds from the producers did not detect Salmonella. However, continued international investigations further implicated seeds sourced from the same origin, supporting that alfalfa seeds were the ultimate source of the Swedish outbreak. Our investigation and findings indicate that alfalfa sprouts may contain Salmonella and thus pose a health risk to consumers. We emphasize the need for primary producers of alfalfa seeds and sprouts to identify and prevent possible contamination points.

This surveillance report describes the epidemiology and clinical outcomes of carbapenem-resistant Enterobacterales (CRE) infections in Tennessee from 2016 to 2022, analysing 570 cases and 406 isolates. The incidence of CRE infections per 100 000 population showed an upward trend. Enterobacter species were the most common organisms, whereas Klebsiella species were the main carbapenemase-producing CRE (CP-CRE). Klebsiella pneumoniae carbapenemase was the most common mechanism contributing to this resistance. Demographic characteristics of patients with identified isolates demonstrated a median age of 69.5 years. There were no significant differences in CP-CRE infection by sex or race. Patients with CP-CRE were more likely to be hospitalized than those with non-CP-CRE, at 60.9% and 43.9%, respectively. Multivariable analysis indicated that patients with CP-CRE had significantly higher odds of 90-day mortality (odds ratio, 2.22; 95% confidence interval, 1.12-4.42; p < 0.0001) than non-CP-CRE patients. Individuals with a higher Charlson Comorbidity Index score exhibited an increased odds of dying within 30- and 90-day post-specimen collection and had a greater likelihood of requiring intensive care unit admission. This report underscores the need to understand the epidemiology and risk factors linked to CRE infections to improve prevention strategies and patient care.

Toxoplasmosis during pregnancy can cause congenital malformations and fetal death. This study aimed to estimate the Toxoplasma gondii seroprevalence among pregnant women participating in the 2021 French national perinatal survey and identify associated factors. All women giving birth in France during the study period were invited to participate. Data collected included demographic information, nationality, socio-economic status, education level, and Toxoplasma gondii serological status. Women were classified as seropositive if IgG antibodies were present or if seroconversion occurred during pregnancy. Univariate and multivariate Poisson regression analyses with robust error variance were used to estimate prevalence ratios and identify factors associated with seropositivity. Among 12,612 women, the overall seroprevalence was 25.9%, and 0.22% seroconverted during pregnancy. Seroprevalence increased by 5% with every 5-year age increment and was significantly higher in the French overseas territories of Mayotte (75.0%), La Réunion (35.8%), and French Guiana (33.3%). Seroprevalence was also higher among women with lower educational levels (47.4% for primary education) and those of Sub-Saharan African nationality (52.0%). Geographic and socio-demographic variations may reflect dietary and environmental diversity. Despite declining seroprevalence in France, continued public health efforts, particularly among high-risk populations, remain critical to minimize the impact of congenital toxoplasmosis.

Pneumococcal conjugate vaccines (PCVs) have influenced population dynamics of Streptococcus pneumoniae in the nasopharynx and may have contributed to increased Staphylococcus aureus colonization. This study assessed the prevalence of colonization, antibiotic resistance patterns, and associated risk factors for colonization and co-colonization of S. aureus and S. pneumoniae in healthy Peruvian children post-PCV introduction. Nasopharyngeal swabs from children <24 months were collected in five hospitals in Lima (2018-2019). Microbiological identification and antibiotic susceptibility tests were performed, and multinomial regression evaluated factors influencing colonization. Among 894 children, 19.7% were colonized with S. aureus, 20.3% with S. pneumoniae, and 2.9% co-colonized. Of the 176 S. aureus strains isolated, 1.7% were methicillin resistant and 20.5% were clindamycin resistant; no resistance to trimethoprim-sulfamethoxazole (SXT) was found. Among 182 S. pneumoniae strains isolated, 48.9% were resistant to macrolides, 74.7% to SXT; no resistance to penicillin was found. Breastfeeding and vaccination with PCV13 were associated with a reduced prevalence of S. aureus colonization, while vaccination with PCV13 increased the prevalence of S. pneumoniae colonization, mainly by non-vaccine serotypes. This study highlights the need to continue monitoring the changes in colonization dynamics and antimicrobial resistance patterns after vaccine introduction, to guide empirical therapy and future vaccine strategies.

Invasive Escherichia coli disease (IED) is associated with high hospitalization and mortality rates, particularly among adults aged ≥60 years. O-antigens are virulence factors required for E. coli survival. To inform EXPEC9V development, a novel glycoconjugate vaccine targeting E. coli O-antigens that is no longer in active clinical development, this retrospective observational study describes O-serotype prevalence among E. coli isolates from IED patients. Eligible patients were identified from medical record databases (9 January 2018-8 November 2019) across 17 tertiary care hospitals in Europe, North America, and Asia. To estimate vaccine serotype coverage of EXPEC9V, E. coli isolates were O-serotyped using whole-genome sequencing and agglutination. Antimicrobial susceptibility testing was also performed. Nine hundred and two patients were enrolled, of whom 690 (76.5%) were aged ≥60 years. Common serotypes were O25, O2, O6, O1, O15, O75, O16, O4, and O18, with O25 being the most reported (17.3%). In patients aged ≥60 years, 422/637 E. coli isolates were EXPEC9V O-serotypes. EXPEC9V O-serotype prevalence did not substantially differ when stratified according to sex, presence of a positive blood culture, sepsis, fatality, or multidrug resistance. Consistent with previous studies, serotype O25 was most prevalent and associated with ~20% of cases. An EXPEC9V vaccine serotype coverage of 66.2% was observed for IED patients aged ≥60 years.

This study aims to estimate the prevalence of human papillomavirus (HPV) infection and describe its genotype distribution in MSM in Hong Kong. In this longitudinal study on Chinese MSM, multi-anatomic site self-sampling and testing for HPV, Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) were performed following survey completion at baseline and one-year follow-up. Overall, 41% (288/701) of MSM completed self-sampled HPV testing. HPV positivity was 29% (78/270) and 33% (42/127) at any anatomic site at baseline and follow-up timepoints, respectively. By anatomic site, HPV positivity was 26%-30%, 2%-4% and 0%-1% from rectal, penile, and pharyngeal specimens, respectively. The incidence of HPV infection was 21.2/100 and 18.9/100 person-years at any anatomic site and rectal site, respectively. Among 109 successfully genotyped samples, the most prevalent were HPV 6 (17%) and HPV 11 (16%), of which 60% of the genotyped samples were vaccine-preventable. Group sex engagement and less frequent condom use were positively associated with HPV infection (P<0.05). The HPV prevalence and incidence in MSM in this study is lower than in Western countries, and low-risk HPV genotypes are more prevalent. The high proportion of vaccine-preventable HPV subtypes underscores the importance of HPV vaccination in preventing infections in MSM.

Leptospirosis remains a significant occupational zoonosis in New Zealand, and emerging serovar shifts warrant a closer examination of climate-related transmission pathways. This study aimed to examine whether total monthly rainfall is associated with reported leptospirosis in humans in New Zealand. Poisson and negative binomial models were developed to examine the relationship between rainfall at 0-, 1-, 2-, and 3-month lags and the incidence of leptospirosis during the month of the report. Total monthly rainfall was positively associated with the occurrence of human leptospirosis in the following month by a factor of 1.017 (95% CI: 1.007-1.026), 1.023 at the 2-month lag (95% CI:1.013-1.032), and 1.018 at the 3-month lag (95% CI: 1.009-1.028) for every additional cm of rainfall. Variation was present in the magnitude of association for each of the individual serovars considered, suggesting different exposure pathways. Assuming that the observed associations are causal, this study supports that additional human cases are likely to occur associated with increased levels of rainfall. This provides the first evidence for including rainfall in a leptospirosis early warning system and to design targeted communication and prevention measures and provide resource allocation, particularly after heavy rainfall in New Zealand.