Emerging Infectious Diseases

BackgroundAustralia is experiencing its worst syphilis epidemic in decades, driven by two distinct outbreaks -- a heterosexual epidemic disproportionately affecting Aboriginal and Torres Strait Islander communities in northern Australia, and a predominantly MSM-associated epidemic in urban centres. We examined the spatial dynamics of this dual epidemic, including geographic clustering, service accessibility associations, and COVID-19 impacts. MethodsWe analysed publicly available aggregate surv...

Strengthening in-country sequencing capacity generated 28 Lassa virus genomes from human clinical cases, expanding our knowledge of Lassa fever in Guinea. Phylogeographic analysis revealed cross-border exchange between Liberia and the NZerekore region, and a Sierra Leone introduction into the Gueckedou area. Enhanced genomic surveillance is crucial to guide future public health actions.

BackgroundViral hemorrhagic fevers (VHFs) remain a major public health threat in resource-limited settings. The 2014-2016 Ebola virus disease epidemic exposed critical gaps in laboratory preparedness and diagnostic capacity in most-at-risk countries, including Guinea. Sustainable in-country laboratory capacity is essential for early detection and rapid response to VHF outbreaks, including Lassa fever. MethodsA long-term laboratory capacity-strengthening programme was implemented in Guinea, comb...

BackgroundHeartland virus (HRTV) is an emerging tick-borne virus capable of causing severe illness and death. The burden of disease is likely underestimated due to limited seroprevalence studies, lack of commercially available diagnostic tests, and an overlapping clinical syndrome with more commonly diagnosed bacterial diseases such as spotted fever group rickettsiosis or ehrlichiosis. MethodsActive surveillance for Heartland virus disease was conducted at a large academic center from March to ...

Household transmission of EV-D68 was identified in 35 of 1040 households (3.4%) in the Pacific Northwest between 2022-2024, with an estimated secondary attack rate of 15%. Sequences from within households clustered closely with 0 to 2 pairwise nucleotide differences (median 1) between cases 6-14 days apart (median 7).

Influenza A(H3N2) subclade K virus was detected in Canada early in the 2025/26 influenza season, bearing an antigenic transition in the hemagglutinin (HA) glycoprotein. Analysis of 396 HA sequences from Canada showed antigenic divergence from 2025/26 influenza vaccine strains, consistent with partial mismatch. Phylodynamic analysis revealed sustained pre-vaccine transmission without clear post-vaccine expansion. Phylogenetic and phylogeographic analyses indicated interprovincial mixing within a ...

BackgroundElimination of Plasmodium vivax is challenging due to its dormant liver stages (hypnozoites), which can reactivate weeks or months after the primary infection, causing relapses and ongoing transmission of the parasite. Despite these challenges, P. vivax clinical case numbers have declined over the past decade in Cambodia. We used parasite genotyping to assess whether the decline in case numbers was reflected in parasite diversity and relatedness as a proxy to transmission. MethodsGeno...

The measles outbreak in Jalisco, Mexico (January-February 2026) experienced vigorous sustained transmission with an exponential growth rate = 0.10 (95% CI: 0.10-0.11) per day, doubling time = 6.3 days (95% CI: 6.3-6.9), yielding the effective reproduction number at 3.34 (95% CI: 3.16-3.54), with elevated incidence among infants and young adults.

Linezolid is a critical last-resort antimicrobial for multidrug-resistant Enterococcus faecium, particularly against vancomycin-resistant lineages where therapeutic options are severely limited. While resistance has historically arisen through de novo chromosomal mutations, the global emergence of transferable resistance mechanisms threatens to render more infections untreatable. Here, we characterise a recent (2023-2024) hospital-associated outbreak of linezolid-resistant E. faecium in Queensla...

Bacterial infections are a major cause of morbidity and mortality among children under five in low- and middle-income countries (LMICs). Children in LMICs are exposed to and colonized by a range of pathogenic bacteria, yet patterns of bacterial exchange between humans are not well known, in part because culturing and sequencing single bacterial isolates is labor-intensive. Here, we apply a machine learning strain tracking approach to metagenomic data from 511 stool samples from children and moth...

BackgroundAfrica continues to have a significant public health problem with mpox, where endemic transmission persists and overlaps with a high burden of other infectious diseases. Although their epidemiology and clinical impact are still poorly understood throughout the continent, coinfections with human immunodeficiency virus (HIV) and varicella-zoster virus (VZV) can affect the clinical picture, severity of the disease, and accuracy of the diagnosis. MethodsFollowing PRISMA criteria, we regis...

Genomic surveillance of influenza viruses informs vaccine strain selection and evolutionary forecasting. Sequencing efforts vary widely across U.S. states, which raises concerns about spatial sampling bias. We evaluated how well 10,958 influenza virus genomes sampled by our group in Michigan captured the genetic diversity in 34,743 genomes circulating nationally from the 2021/22 through 2024/25 seasons. We defined seasonal hemagglutinin haplotypes and tracked their detection across states. A sma...

From 2021 to 2025, MRSA emerged as a major multidrug-resistant pathogen in the study area. Among 545 S. aureus isolates, 67.2% were MRSA, disproportionately affecting children under five (26.5%) and males (55.5%). Case incidence more than doubled by 2025, suggesting rising transmission or resistance. Most isolates were hospital-associated (85.2%), predominantly from outpatients (88.5%), with middle ear discharge as the main source (67%). Gentamicin showed the highest susceptibility (72.1%), whil...

BackgroundClostridium perfringens can cause life-threatening extraintestinal infections in immunocompromised patients, an area in which we have little information regarding strain factors that impact patient risks and outcomes. MethodsWe conducted genomic-epidemiologic analyses on C. perfringens isolates from 70 patients seen at Brigham and Womens Hospital over 2021-2024. Genomic analyses evaluated strain profiles within a broader context of 2,321 C. perfringens genomes from foodborne, veterina...

BackgroundTesting blood samples with multiplex bead assays can assess elimination and identify residual foci of transmission for multiple pathogens simultaneously. In Ecuador, onchocerciasis and yaws are presumed eliminated, and the status of trachoma is unknown. We assessed their elimination status by measuring IgG antibodies in children 6-24 months. MethodsIn a birth cohort of 404 children measured between 2021-2024 in Esmeraldas province, Ecuador, we tested dried blood spots at ages 6, 9, 12...

In the past decade, dengue fever has emerged as a major public health on Reunion Island in the Southwest Indian Ocean. During the 2018-2022 outbreak, an unusual increase in ocular complications was reported in some patients. To investigate a potential viral cause, we analysed 447 blood samples from hospitalized patients with and without ophthalmic symptoms. Genetic sequencing revealed the co-circulation of two strains of dengue virus serotype 1, both genetically linked to strains previously iden...

Serological surveillance is fundamental to infectious disease research and informed public-health decision making. Immunoassays used in the study of pathogen-specific immunity have historically relied on the collection of venous blood. While critical for many public-health applications, this sample collection method is invasive and resource intensive. The costs and logistical barriers associated with venous blood collection are exacerbated in resource-limited regions, and the shift to less invas...

BackgroundImmunocompromised (IC) individuals are at increased risk for persistent SARS-CoV-2 infections and can develop new viral mutations and lineages not seen in the community. In this case report, a persistent SARS-CoV-2 infection (330 days) in an IC patient is examined for viral mutations and mutations associated with cryptic lineages. Case PresentationThe patient was followed in a longitudinal study examining persistent SARS-CoV-2 in IC patients. The patient provided stool and nasal swab ...

BackgroundCambodia has made great progress in reducing malaria transmission and is targeting elimination. While this progress is particularly marked for Plasmodium falciparum, the situation is different for Plasmodium vivax. It is generally assumed that symptomatic patients are effectively diagnosed using rapid diagnostic tests (RDTs), regardless of transmission intensity. MethodsIn 2023 we conducted a cross-sectional survey among 986 treatment-seeking patients in 6 provinces of Cambodia with v...

IntroductionDengue has been prevalent in a regular fashion in Bangladesh and Chattogram for the last 6-7 years and is showing some serotype twisting. So, the objectives of the present study were to explore the burden of dengue serotypes in Chattogram. MethodsIn this study, 223 Dengue RT-PCR positive patients were evaluated for serotyping. Gender and age group, along with cycle threshold (CT) values, were also collected. Data after collection were compiled, analyzed, and plotted in Microsoft Exc...