Encephalitis lethargica (EL), also known as the 'European Sleeping Sickness', emerged in Europe around 1916, with Sweden reporting the highest global incidence rate in 1921. This study investigates regional variations in EL incidence across Sweden between 1920 and 1930, with a particular focus on the major outbreak in 1921. Using data from Public Health in Sweden, incidence rates were calculated for all Swedish regions, revealing a disproportionate concentration of cases in central and northern areas, especially in the parish of Vilhelmina in Västerbotten. To contextualize this outbreak, monthly disease data from the Annual Reports of the Chief Provincial Doctor in Västerbotten were analysed to compare the local disease panorama. Notably, preceding the first EL cases in Vilhelmina, influenza/H1N1 and mumps were frequently reported. Although the aetiology of EL remains unresolved, the presence of a preceding influenza and mumps epidemic is consistent with the dual-pathogen hypothesis, suggesting that interactions between infectious agents may have contributed to the emergence of EL in local hotspots.
The World Health Organization (WHO) has set global goals to eliminate AIDS and viral hepatitis as public health threats. To better target testing, intelligence on missed opportunities for early diagnosis is needed. We determined hospital and emergency department (ED) attendance before late diagnosis of blood-borne viruses (BBVs) in Scotland 5 years to 2 months prior to diagnosis. Late diagnoses were defined as: CD4 count <350 cells/cmm within 90 days of HIV diagnosis; presentation/death from cirrhosis or hepatocellular carcinoma within 1 year of hepatitis C (HCV)/hepatitis B (HBV) diagnosis. Associations were assessed using logistic regression. Among 543 people diagnosed with HIV 37% were late and 2% of people diagnosed with HCV (4,379) and HBV (1,608) were late. Among late diagnoses: 44.1% of HIV, 60.6% of HCV, and 50% of HBV cases previously attended ED and 27.0% of HIV, 46.5% of HCV, and >30% of HBV cases were previously admitted to hospital. The majority were admitted to hospital or attended ED multiple times. Among people newly diagnosed with HIV, those diagnosed late were more likely to have previously attended ED (aOR: 1.41, CI: 0.99-2.02). Further effort is warranted to address the frequent missed opportunities for earlier BBV diagnosis in secondary care.
On 4 December 2023, trichinellosis cases were notified in Jahliyeh, Mount Lebanon. We investigated to determine the source, magnitude, and control measures. We defined a suspected case as a Jahliyeh resident with ≥1 compatible symptom diagnosed by a physician after 1 October 2023; a probable case as having ≥3 typical symptoms (fever, myalgia, edema, or eosinophilia); and a confirmed case as a suspected or probable case with laboratory confirmation by muscle biopsy or serology. We surveyed reachable households (252/561) to identify cases and assess meat consumption practices, inspected local butcheries, and tested meat samples. We identified 290 cases: 268 (92%) suspected, 21 (7.2%) probable, and 1 (0.3%) confirmed. Median age was 35 years (range 2-85); 34% required hospitalization. Illness was associated with Butchery A meat (risk ratio [RR] = 8.2; 95% confidence interval [CI]: 5.6-12.1) and uncooked meat (RR = 1.9; 95% CI: 1.4-2.6), while freezing and cooking were protective. Food inspection revealed major hygiene breaches at Butchery A and Trichinella larvae in minced beef and sausage. This outbreak was epidemiologically confirmed despite limited laboratory confirmation in humans. We recommend strengthening food safety inspections, intersectoral One Health collaboration, laboratory capacity, and public awareness of safe meat preparation.
In this proof-of-concept study, we explored the potential of structured general practice data for early signal detection, to enhance pandemic preparedness. We used electronic health record data from the Family Medicine Network (FaMe-Net) in the Netherlands between 2014 and 2024. Descriptive evaluation with surveillance attributes was performed, and the Farrington flexible method was used to construct an alert threshold for respiratory, gastroenteritis, rash, infectious conjunctivitis, and fever syndromes. Alert signals were generated, indicating when the observed weekly count exceeded the threshold. This data registry performed adequately for most surveillance attributes. We analysed 634708 diagnostic codes and 9 infectious disease syndromes in the data registry. In 154 weeks, the number of alert signals ranged from 3 to 20. We found similarities and variations in the number of alert signals between infectious syndrome definitions within the different data types. Structured general practice data showed potential for surveillance and early signal detection of infectious diseases because it performed well on most surveillance attributes and weekly counts of infectious disease syndromes led to the generation of alert signals. Further validation of these alert signals is needed, to underpin their early warning potential for timely public health action.
The infection fatality risk indicates the probability of death among infected individuals. The age-dependent heterogeneity of infection fatality risk is crucial for severity assessment and prioritization of countermeasures. However, infection fatality risk estimation requires infection data from a large-scale seroepidemiological survey combined with either direct ascertainment of deaths caused by infection or excess mortality estimates. To overcome the difficulty in ascertaining death, we propose an alternative approach to estimating the age-specific infection fatality risk for SARS-CoV-2 using medicolegal death investigation data in Tokyo with systematic post-mortem polymerase chain reaction testing. We integrated (i) polymerase chain reaction positivity among all deceased individuals at the Tokyo Medical Examiner's Office, (ii) age-specific all-cause mortality risks from vital statistics, and (iii) age-stratified cumulative infection risks derived from seroepidemiological surveys. Infection fatality risk was computed using Bayes' theorem. Results showed that infection fatality risk increased steeply with age. Our estimates (0.02% for ages 0-39 years, 0.30%-0.50% for ages 40-64 years, and 3.8%-4.2% for those aged ≥65 years) were consistent with published pre-vaccination meta-analytic estimates. Systematic testing within medicolegal death investigation systems can provide rapid, age-resolved severity assessments, improving the timeliness and comparability of infection fatality risk estimation across jurisdictions.
Maternal syphilis and congenital syphilis (CS) have been increasing globally, but there are limited data from Fiji. We performed secondary analysis of clinical trial data of intrapartum azithromycin given to pregnant women to determine the prevalence of maternal syphilis and estimate the incidence of probable CS. Healthy, pregnant women at a tertiary hospital were routinely tested for syphilis, and their infants, were enrolled between July 2019 and January 2022. World Health Organisation case definitions for maternal and CS were used. Of the 2112 women enrolled, 2073 (98.2%) were tested for syphilis; 82.7% (n = 1715) were iTaukei (indigenous Fijians), and the median age was 27 years (interquartile range [IQR] 23-32). The maternal syphilis prevalence was 6.6% (n = 137). The majority (85.4%, n = 117) of women with positive serological result received at least one dose of benzathine penicillin 30 days prior to delivery. There were 139 infants born to mothers with positive serological results. The 2.5-year pooled incidence of probable CS was 212 per 100000 livebirths. Confirmation of CS was not possible as results of polymerase chain reaction test of cerebrospinal fluid were not available. Fiji has a substantial burden of maternal and CS. To eliminate mother-to-child transmission, improvements in testing and follow-up are needed, along with comprehensive data and confirmatory testing to accurately determine disease burden.
Spatial risk models for Lassa fever (LF) generally predict the primary reservoir, Mastomys natalensis, is restricted to rural landscapes. This study integrates multispecies biotic interactions and anthropogenic land-use into a high-resolution framework to evaluate LF's urban potential. I implemented an integrated multispecies occupancy model to reconstruct the reservoir's realized niche, accounting for sampling bias and invasive rodent competitors. A socio-economic filter, proxied by night-time lights, was introduced to model the dampening effect of urban infrastructure on spillover. Annual infections were estimated using a demographic compartmental model incorporating empirical seroreversion rates. Results indicate high biological hazard across the peri-urban fringes of major West African cities. However, an infrastructure-driven socio-economic shield decouples this hazard from human incidence in dense urban cores. Accounting for spatial shielding and antibody waning yields an estimated 2.6 million annual Lassa virus infections. Comparing predictions to clinical data reveals substantial surveillance gaps, identifying highly suitable silent districts in Nigeria, Benin, and Togo with zero reported cases. LF possesses the biological potential to become a peri-urban disease; addressing these surveillance gaps at the peri-urban interface is a critical public health priority.
Mpox has evolved into a global public health concern following rapid geographic expansion and altered clinical and epidemiological characteristics. The 2022 outbreak of monkeypox virus (MPXV) marked the first widespread expansion to non-endemic regions, particularly among men who have sex with men (MSM). In the Democratic Republic of the Congo (DRC), where Clade I MPXV is endemic, data on urban exposures are limited. We evaluated serologic evidence of exposure using a four-plex MPXV assay among 1,823 participants from two major DRC cities, Kinshasa and Goma, between April and June 2024. Of these participants, 523 (28.7%) self-identified as MSM, 498 (27.3%) as professional sex workers (SW), 107 (5.9%) as MSM and SW, and 695 (38.1%) as other at-risk individuals. Overall, 2.9% of participants were seroreactive. By subpopulation, 4.8%, 2.1%, and 1.7% of at-risk, MSM, and SW participants were seroreactive (p = 0.0086). Classification tree modelling identified age as the strongest predictor of reactivity, with higher MPXV seroreactivity in older participants. These data provide evidence of mpox seroreactivity prior to sustained human-to-human transmission in urban settings. Understanding exposure dynamics is critical for anticipating re-emergence of mpox in global cities where interpersonal networks may sustain transmission even in the absence of zoonotic spillover.
Acute otitis media (AOM) is a major driver of paediatric antibiotic prescriptions. We assessed the impact of oral and topical antibiotics on middle ear, nasopharyngeal, and gut microbiome compositions, and the gut resistome, in children with AOM and ear discharge (AOMd). Fifty-eight children with AOMd and ear pain and/or fever were randomized to oral amoxicillin suspension (n = 31) or hydrocortisone-bacitracin-colistin eardrops (n = 27) for 7 days. From 57 out of 58 children, baseline, and Week-2 middle ear fluid (MEF) and nasopharyngeal (NP) samples were sequenced, along with baseline, Week-2, and Month-3 faecal samples. At baseline, the top 5 MEF genera were Streptococcus, Haemophilus, Turicella, Staphylococcus and Alloiococcus and NP genera Moraxella, Haemophilus, Streptococcus, Corynebacterium, and Dolosigranulum. At Week-2, the ear discharge had resolved in all but four children (oral n = 3, eardrops n = 1). In NP samples, the relative and absolute abundances of Streptococcus decreased to a greater extent after oral than eardrop treatment, but Moraxella and Haemophilus increased only following oral treatment. Neither treatment significantly altered the faecal microbiome or resistome at Week-2 and Month-3. Therefore, both treatments resolved the middle ear discharge in most children, but oral amoxicillin suspension may reduce NP Streptococcus more than hydrocortisone-bacitracin-colistin eardrops at the cost of potentially increasing other NP pathobionts.
While malaria transmission in coastal East Africa is strongly shaped by climatic variability, few studies examine long-term interactions in rapidly urbanizing settings. This study evaluated the impact of climate and seasonal trends on malaria incidence in Dar es Salaam, Tanzania (2014-2024). Monthly cases and meteorological data were analyzed using seasonal-trend decomposition (STL) and generalized additive models (GAMs) to quantify nonlinear and lagged climatic associations. Over the decade, malaria incidence declined sharply from >130 cases per 10,000 in 2014 to <30 by 2023. However, strong seasonal peaks persisted, with STL revealing consistent annual surges during April-June following the rainy season. GAM analysis identified rainfall as the dominant climatic driver, demonstrating significant 1- and 2-month lagged effects (p < 0.001). Daytime (1-month lag) and night-time (2-month lag) temperatures showed non-linear associations, peaking in incidence at optimal mosquito-development temperatures (~30-31°C). Despite substantial incidence declines, transmission remains highly climate-sensitive. Driven primarily by lagged rainfall and temperature effects rather than current-month conditions, these dynamics underscore the urgent need for climate-informed early warning systems and targeted seasonal interventions in coastal urban environments.
Late HIV diagnosis increases morbidity and mortality. In this retrospective cohort study on the national HIV register, we analysed risk factors for late HIV diagnosis among newly registered people living with HIV (PLWH) between 2008 and 2023, using the updated definition. Of 2683 PLWH registered, 1813 (67.6%) were newly diagnosed with CD4+ T-cell count available ≤90 days for 1572 (86.7%). Eighty-seven of the 609 (14.3%) individuals with CD4+ T-cell count <350/μL had recent infections and were reclassified as non-late. Of the newly diagnosed, 50.3% were diagnosed late. Multivariable analysis identified higher age as an independent risk factor for late diagnosis (adjusted OR 1.42 per ten years, 95% CI 1.30-1.56). Of the Finnish-born, females had lower odds than males (aOR 0.59, 95% CI 0.39-0.88). Asian-born (aOR 6.83, 95% CI 3.49-13.35) and African-born females (aOR 3.26, 95% CI 1.58-6.73) had significantly higher odds than Finnish-born females. In urban municipalities, men who have sex with men had lower odds than individuals with heterosexual transmission (aOR 0.55, 95% CI 0.40-0.76). Higher age was the most important factor for increasing the proportion of late diagnoses. We recommend enhanced testing and risk awareness for older adults and migrants from high-prevalence countries.
In England, Lyme disease (LD) surveillance is based on laboratory-confirmed cases. However, clinical and epidemiological characteristics of these cases are limited; therefore, we conducted an enhanced surveillance study of acute LD in England. Enhanced data were collected through an online questionnaire sent to all laboratory-confirmed acute cases of LD resident in England, with specimen dates between 1 April 2023 and 31 March 2024. The analysis included data from 511/1086 cases. Respondents were representative of age, sex, and region of national LD trends. A total of 57.3% of the respondents reported that they did not realize that they had been bitten by a tick. Among those who remembered a tick bite, 66.1% reported bites close to their home and only 10.6% happened abroad, and 28.5% reported that the tick bite could have occurred in a garden. Most respondents were residents of areas of higher socioeconomic status. Erythema migrans was noted by 70.5% of the respondents. It is important to raise awareness among both patients and clinicians that ticks can be found in urban and suburban parks and gardens, as well as ensuring that wildlife initiatives to increase biodiversity include information on tick prevention and tick checks.
Care homes are vulnerable to respiratory syncytial virus (RSV) outbreaks, with residents at risk of severe disease outcomes, though surveillance studies are lacking. In September 2024, RSV vaccination was introduced for adults in England aged 75-79 years, excluding most residents (median age 86 years). Between October 2024 and March 2025, we prospectively extracted information on RSV outbreaks in English care homes reported to UK Health Security Agency (UKHSA). Enhanced surveillance questionnaires (ESQs) were completed for a sample of outbreaks, including information on symptomatic residents, testing, and outcomes. Acute respiratory infection (ARI) cases were defined symptomatically, RSV cases based on test-positive RSV (≤5 residents tested per home), and RSV outbreaks as ARI outbreaks including ≥1 RSV case. We described outbreak trends, attack rates, hospitalizations, and deaths. Of 2419 ARI outbreaks in care homes, 222 (9%) were RSV outbreaks, with additional respiratory viruses identified in 69 (31%). Among 48 (22%) RSV outbreaks completing ESQs, the median ARI attack rate was 15% (IQR 10%-24%). Of 350 ARI cases, 32% (112) were confirmed RSV cases on routine testing, 20% (71) were hospitalized, and 6% (20) died. These findings demonstrate the vulnerability of care home residents to RSV infection, hospitalization, and death, which are potentially preventable through vaccination.
We aimed to comprehensively assess Stenotrophomonas maltophilia infections, examining their incidence and clinical and microbiological characteristics in a tertiary hospital between 2021 and 2023. Primary outcomes were 30-day mortality and desirability-of-outcome ranking (DOOR). S. maltophilia incidence rose from 0.38 in 2017 to 2.66 cases/1000 patient-days in 2023, correlated with carbapenem consumption (rho = 0.90, p = 0.04). The cohort included 101 patients (median age of 61 years, IQR 43-71); 63% were male patients, 91% admitted in ICU, predominantly with lower respiratory tract infections (75%). Difficult-to-treat resistance (DTR) was identified in 14% of the isolates and associated with previous trimethoprim-sulfamethoxazole (TMP-SMX) use (aOR 23.15, 95% CI 3.67-145.77). Thirty-day mortality was 25% and associated with invasive mechanical ventilation (aOR 5.80, 95% CI 1.03-32.63), while appropriate definitive therapy was protective (aOR 0.01, 95% CI <0.01-0.16). Worse DOOR outcomes were associated with levofloxacin-resistant isolates (69.3%, CI 55.9%-80.9%) and inappropriate definitive treatment (81.1%, 95% CI 68.2%-90.8%). Overall, S. maltophilia has emerged as a relevant carbapenem-resistant gram-negative bacteria, with a high frequency of DTR phenotypes associated with previous TMP-SMX exposure. Appropriate therapy and levofloxacin susceptibility were linked to better outcomes.
Seabirds are at high risk of extinction, and the emergence of highly pathogenic avian influenza virus (HPAIV) represents an additional threat. In 2024, HPAIV A/H5 clade 2.3.4.4b was detected for the first time in the Antarctic Continent in a dead Brown Skua (Stercorarius antarcticus), and further evidence suggests that not all species have been equally affected. We conducted a survey of HPAIV-related mortalities across 16 seabird nesting sites along the western Antarctic Peninsula (WAP) during the 2024-2025 breeding season. We report a mortality of 35 adult skuas along the WAP and beyond the Antarctic Polar Circle. Eleven skuas from six different geographic areas were sampled and all were positive to HPAIV A/H5 clade 2.3.4.4b. Phylogenetic analyses revealed that these sequences are closely related to the initial HPAIV A/H5 clade 2.3.4.4b reported in Antarctica, and post-mortem findings suggest that the viral infection was likely the cause of death. No other suspected HPAIV-related mortalities were observed in sympatric species. Our findings represent the southernmost record of skua mortality in Antarctica related to HPAIV A/H5 infection to date, demonstrating the dissemination of 2.3.4.4b clade across several localities. The virus is differentially affecting sympatric seabird species and the skuas may act as sentinel species for influenza surveillance.
Progress in reducing global malaria incidence has slowed in recent years, demonstrating the need for new vector control tools to complement existing interventions in reaching global malaria control targets. Spatial repellents (SRs) can reduce pathogen transmission by altering the behaviors of Anopheles spp. mosquito vectors. A recent cluster-randomized control trial in western Kenya found that SRs reduced first-time infections by 33.4% in a highly-endemic setting with substantial insecticide resistance and high coverage of insecticide treated nets. We modeled the likely impact of the SR intervention in this setting under different deployment strategies, with the goal of identifying the best overall and per-product strategies. Continuous monthly SR deployment with 100% coverage caused the greatest (45.1%) reduction in infections versus no SR, although some seasonal approaches averted more infections per SR product. Six months of SR use starting in October caused a 36.4% reduction in infections and eight months starting in September reduced infections by 44.7%. This study identified optimum and efficient SR use strategies and highlights the importance of SR protection during periods of low and increasing transmission. When resources are limited, the coverage, deployment strategy, and timing of SR deployment all play a key role in maximizing product impact.
Rabies is a fatal zoonotic disease causing an estimated 59000 annual human deaths globally and approximately 523 in Kenya, with children disproportionately affected. Despite evidence that school-based educational interventions effectively increase rabies awareness and prevention among children, its implementation in Kenya is limited. This study aimed at utilizing an education programme to increase rabies awareness among primary school learners and evaluate their knowledge uptake. A quasi-experimental study was conducted among 210 learners from four primary schools (two urban, two rural). Pre-tested questionnaires assessed rabies awareness before and after rabies training sessions. Differences between urban and rural schools were assessed using χ2 tests, while Wilcoxon signed-rank test was used for pre- and post-training scores. Post-training, overall knowledge scores improved from 6.14 to 7.61(p < 0.001), with significant increase in learners' knowledge on rabies transmission, zoonosis, and the importance of annual dog vaccination. Attitudes and perceptions improved from 3.23 to 4.03 (p < 0.001), particularly health-seeking behaviour and reporting post dog bite. In conclusion, school-based rabies education significantly improved learners' awareness. Being the first report of such intervention in Kenya, it could serve as a model for other zoonoses.
Commonly used components of health risk assessments and outbreak investigations are the proportion of the general population exposed to potential sources, often coming from national surveys collected with one reference period, such as 7 days. However, risk assessors may need this value for a different period of time (e.g. 1 day, a full year, etc.) and outbreak investigators may need a reference period that matches their case questionnaire. Use of these proportions is biased if the reference period does not match what is needed. Three surveys that collected exposure information with more than one reference group were used to fit six models that were developed to estimate the relationship between proportion and reference period length, and thus, convert proportions collected with one reference period to any desired reference period. A practical implementation of the best model is provided in a spreadsheet for health practitioners, such as those working in risk assessment or outbreaks who need to convert proportions to a new reference period. The conversion method can be used in any subject matter across the sciences, where surveys collect the proportion of respondents who experienced an event in a defined reference period.
Syphilis remains a significant transfusion-transmitted infection. In Colombia, routine epidemiological surveillance primarily targets pregnant women, leaving the burden of infection among the apparently healthy population. This study determined the incidence of Treponema pallidum and its associated factors in donors at a blood centre in Colombia between 2012 and 2024. A retrospective cohort study was conducted, analyzing 64,166 repeat blood donors. Incidence was calculated using 95% confidence intervals. Associations with demographic and donation-related variables were assessed using Chi-square test and potential confounders were adjusted using a multivariable regression model. The overall incidence of syphilis was 5.1 per 1,000 donors. The associated factors included age, sex, occupation, collection site, and donor type. Higher incidence proportions were observed in male donors (RR = 1.76), individuals aged between 60 and 65 years (RR = 2.43), unemployed individuals (RR = 3), donors collected at the centre (RR = 1.45), and replacement donors (RR = 3.51). These incidences indicate ongoing transmission within a low-risk population. The highest incidence in some groups enabled the generation of hypotheses about differential exposure patterns, guiding subsequent aetiological studies, and optimizing donor selection. Understanding local epidemiology is essential for designing public health interventions tailored to the specific epidemiological profile.
