Articles from Emerging Infectious Diseases

Streptococcus suis, a swine pathogen that causes zoonotic infections in Europe and Asia, has increasingly been observed in South America. We reviewed all available reports from the continent and identified S. suis cases in Argentina, Brazil, Chile, French Guiana, and Uruguay. We also identified 8 novel infections from Argentina, bringing the total documented human cases in South America to 47. We reclassified 1 previously reported infection as S. parasuis. Among the 47 S. suis cases, 40 (85%) patients had meningitis, 2 (4%) had toxic shock–like illness, 2 (4%) had nonshock sepsis, 1 (2%) had arthritis, and 1 (2%) had endocarditis. The case-fatality rate was 4% (2/47). Infections were primarily linked to pig or pork exposure, although some occurred after consuming undercooked meat. Case distribution varied by country, and Argentina reported a disproportionately high number of cases despite a smaller swine industry. Our findings highlight the need for more consistent regional S. suis surveillance.

Contact investigation is a fundamental component of tuberculosis (TB) programs that drives prompt diagnosis and treatment of Mycobacterium tuberculosis infection among those exposed. Few studies have examined contact investigation costs for TB. We conducted a systematic review of TB contact investigation costs in the United States by searching English-language articles published during January 1990–August 2024 in electronic databases, including MEDLINE, Embase, CINAHL, and Scopus. We identified 2,920 titles and abstracts; 10 studies met our inclusion criteria. We abstracted costs for labor, diagnostic tests, and chest radiographs. Labor cost per contact was estimated at $175.94 (range $79.97–$293.51); total cost, including diagnostic testing and chest radiography, was $228.93 (range $132.95–$346.49).The overall cost of contact investigation in the United States was $9.94 (range $5.77–$15.04) million in 2022; total cost during 2013–2022 was $137.35 million. Contact investigations are essential to prevent TB and avert TB-related labor and diagnostic costs.

Without clarity if an outbreak is natural, accidental, or deliberate, infectious disease outbreaks of unknown or ambiguous origin can lead to speculation of a purposeful biological attack. Outbreaks in conflict settings are particularly prone to suspicions and allegations. In an increasingly confrontative global geopolitical landscape and with active information manipulation, outbreaks of ambiguous origin are likely to increase concerns of the deliberate use of biological agents. The United Nations General Assembly has agreed on and the United Nations Security Council has endorsed a mechanism to investigate allegations of deliberate use titled the United Nations Secretary-General’s Mechanism for Investigation of Alleged Use of Chemical or Biological Weapons. A recent full-scale field exercise evaluated the deployment readiness of the mechanism and found it is well placed to investigate suspicious disease outbreaks, with room for continual improvement.

In New Zealand, OXA-48–producing Escherichia coli is uncommon and typically associated with international travel. We investigated a cluster of 25 patients without recent travel history from Hutt Valley health district, New Zealand, who had multilocus sequence type 131 OXA-48–producing E. coli during August 2018–December 2022. Eighteen had been admitted to Hutt Valley Hospital but did not share a common ward or hospital service. Eighteen had visited the same community-based commercial food premises (premises A); 7 of those had not been admitted to Hutt Valley Hospital. An inspection of premises A revealed multiple hazards, primarily around staff hand hygiene. Four food handlers were colonized with OXA-48–producing E. coli; whole-genome sequencing confirmed genomic links between case and food handler strains, with possible introduction to New Zealand circa 2017. Community-based food premises have a role in propagating OXA-48–producing E. coli in high-income countries, requiring consideration in control strategies.

Talaromycosis is a life-threatening fungal disease that primarily affects immunocompromised persons in Southeast Asia. We conducted a multicenter, case–control study recruiting participants with advanced HIV disease in Vietnam; 205 case-patients with culture-confirmed talaromycosis were matched to 405 control-patients by age, sex, and CD4 count. Occupational exposure to tropical plants (odds ratio [OR] 1.73 [95% CI 1.10–2.73]; p = 0.017) and to farmed animals (OR 2.07 [95% CI 1.20–3.55]; p = 0.009) were independent risk factors for talaromycosis. Talaromycosis risk was higher in participants from highland regions than in persons from lowland regions (p<0.05). Participants from lowland regions who had lived or traveled to highland regions had a higher risk for talaromycosis (OR 3.15 [95% CI 1.49–6.64]; p = 0.003). This study confirms the epidemiologic correlation between talaromycosis and soil exposure and demonstrates an epidemiologic link between talaromycosis and residence in or travel to highland regions of Vietnam.

Free-ranging white-tailed deer (WTD) are highly susceptible to the SARS-CoV-2 virus. Through an opportunistic sampling of WTD in northeast Ohio, USA, during January–March 2023, we identified 6 SARS-CoV-2 lineages from 36 sequences using the pangolin lineages tool, including the B.1.1.7 lineage (Alpha variant) and BQ.1.1, BQ.1.1.63, BQ.1.1.67, BQ.1.23, and XBB.1.5.35 lineages (Omicron variant). The Alpha variant, introduced by a single human-to-deer transmission event, was detected in 5 WTD in January 2023, more than 1 year after the most recent detection of the Alpha variant in humans in Ohio (August 2021). A genetically similar B.1.1.7 lineage virus from WTD in a nearby county in Pennsylvania was positioned with our Ohio deer transmission cluster, suggesting deer-to-deer transmission. The persistence of the Alpha variant in WTD in Ohio warrants continued surveillance to monitor if WTD can become a reservoir for displaced SARS-CoV-2 variants.

We estimated the serial interval and superspreading potential to quantify pertussis transmission dynamics in a 2024 school-based outbreak of a population in South Korea that had received a series of pertussis vaccinations. We analyzed 48 cases of pertussis and reconstructed 36 transmission pairs. We then used maximum-likelihood estimation to assess serial interval and offspring distribution from transmission pair data. We identified that the mean serial interval was 9.5 (SD 1.6) days; 15% (95% CI 8%–23%) of cases seeded 80% of all transmissions in this outbreak. Our findings suggest that pertussis was highly transmissible in vaccinated children during this outbreak. Rapid contact tracing and strict adherence to public health measures are needed to reduce community pertussis transmission.

Determining the incubation period of Oropouche virus disease can inform clinical and public health practice. We analyzed data from 97 travel-associated cases identified by the Centers for Disease Control and Prevention (n = 74) or the GeoSentinel Network (n = 13) and 10 cases from published literature. Using log-normal interval-censored survival analysis, we estimated the median incubation period to be 3.2 (95% CI 2.5–3.9) days. Symptoms developed by 1.1 (95% CI 0.6–1.5) days for 5% of patients, 9.7 (95% CI 6.9–12.5) days for 95% of patients, and 15.4 (95% CI 9.6–21.3) days for 99% of patients. The estimated incubation period range of 1–10 days can be used to assess timing and potential source of exposure in patients with Oropouche symptoms. For patients with symptom onset >2 weeks after return from travel, clinicians and public health responders should consider the possibility of local vectorborne transmission or alternative modes of transmission.

Zoonotic tuberculosis (zTB) is a communicable disease that has major effects on both human and animal health. Spain reports the highest number of zTB cases in humans annually in the European Union. We describe the epidemiology of human cases of zTB caused by Mycobacterium bovis and M. caprae in Spain during 2018–2022. The incidence of M. bovis infection compared with M. tuberculosis infection was higher in patients who were native-born (adjusted odds ratio [aOR) 2.32, 95% CI 1.44–3.82), HIV-negative (aOR 3.39, 95% CI 1.24–14.0), or had extrapulmonary forms of TB (aOR 2.20, 95% CI 1.46–3.28). The spatial pattern differed by M. tuberculosis complex species; we identified 3 significant clusters of M. bovis and 1 of M. caprae in bovine TB–free regions. Our results show the importance of including animal and human data on circulating zoonotic pathogens under the One Health umbrella.

Candida tropicalis is the second most virulent Candida species after C. albicans. Previous studies from the Netherlands and France reported a notable reduction in susceptibility to flucytosine (5-FC) in a substantial proportion of C. tropicalis isolates. We investigated epidemiologic patterns of C. tropicalis isolates in the Netherlands and the genetic mechanisms driving widespread non–wild-type (WT) 5-FC resistance. We conducted antifungal susceptibility testing and used advanced molecular techniques, including short tandem repeat genotyping and whole-genome sequencing paired with single-nucleotide polymorphism analysis, to analyze 250 C. tropicalis isolates collected across the Netherlands during 2012–2022. Our findings revealed the rapid emergence of a 5-FC–resistant, non-WT C. tropicalis clade, accounting for >40% of all C. tropicalis isolates by 2022. Genomic analysis identified a homozygous nonsense mutation in the FCY2 gene, which was exclusive to this non-WT population. Continued surveillance efforts are needed to detect and prevent the spread of drug-resistant Candida species.

Leptospirosis is a global zoonotic disease affecting humans, wildlife, companion, and domestic animals. Incidental hosts can contract the disease directly or indirectly from asymptomatic reservoir hosts, most commonly small rodents. The Golden Syrian hamster is recognized as the dominant rodent model for acute leptospirosis because the animals are susceptible to many serovars and are used to maintain laboratory strains and test bacterin vaccine efficacy. However, hamsters are primarily used in survival-based studies, and investigations into host immune response and disease pathogenesis are limited. We found that Peromyscus leucopus white-footed deer mice are susceptible to acute leptospirosis, and thus might be an alternative rodent model. Furthermore, similar to hamsters, deer mice produce circulating foamy macrophages in response to Leptospira challenge. Deer mice exhibit differences in response to different serovars, clinical disease severity, kidney and liver lesions, and an overall sex effect, with male mice demonstrating more severe clinical signs and higher bacterial burden.

Disseminated histoplasmosis is a major issue among persons with advanced HIV in the Americas; it might also affect persons in sub-Saharan Africa, the Caribbean, and Asia and can be mistaken for other infections. By using 1992–2021 data from the French hospital database on HIV, we analyzed 198,798 persons with HIV follow-up in France and its overseas territories, identifying 553 (2.8/1,000 person-years) first episodes of disseminated histoplasmosis. Incidence rates varied by site of follow-up: 9.41 in French Guiana, 0.76 in Guadeloupe, 0.62 in Martinique, and 0.079 in mainland France. Incidence rates in France also varied between regions of origin or travel: 4.73 for Central or South America, 1.36 for the Caribbean, and 0.19 for sub-Saharan Africa or Asia. Differences persisted after adjusting for age, sex, CD4 count, and viral load at baseline. Overall, incidence and early death have declined, likely because of antiretroviral drug rollout in France.

We analyzed whole-genome sequences of Salmonella enterica serovar Enteritidis isolates in South Korea that had the SEGX01.049 pulsed-field gel electrophoresis pattern. That lineage has emerged and circulated in South Korea since 2020, leading to 2 fatal infection cases. We investigated the genomic characteristics and identified potential sources of that lineage. Isolates from outbreaks during 2020–2023 clustered in the Global IIa clade, along with other Salmonella Enteritidis strains from chicken farms in South Korea and human isolates from the United Kingdom. Bayesian molecular clock analysis estimated the time to the most recent common ancestor of our isolates in the Global IIa clade was 2017.57. Moreover, phylogeographic analysis supported substantial statistical evidence (Bayes factor 111.415; posterior probability 0.97) for the introduction of this lineage into South Korea from the United Kingdom. Continued genomic surveillance will be needed to monitor the spread of foodborne pathogens such as Salmonella Enteritidis and improve prevention strategies.

Shigellosis is a bacterial infection that causes enteric illness and can be sexually transmitted, particularly among gay, bisexual, and other men who have sex with men. Multiple extensively drug-resistant Shigella strains have been detected through genomic surveillance and are associated with plasmids carrying the gene variant bla_CTX-M-27 in the United Kingdom. We report an increase in possible sexually transmitted cases of Shigella bacteria carrying the bla_CTX-M-15 gene variant, which was previously associated with travel. In 2023, there were 117 cases belonging to the 10 single-nucleotide polymorphism linkage cluster t10.1814. Although this cluster has been documented in England since August 2019, genetic analyses revealed that the bla_CTX-M-15 gene variant entered the lineage on a novel resistance plasmid coinciding with the first outbreak case. Our analysis highlights the shifting antimicrobial resistance landscape of sexually transmitted Shigella bacteria. Parallel emergence of resistance determinants against third-generation cephalosporins in sexual transmission networks suggests high levels of antimicrobial selection pressure.

Previous studies investigating the 1918–1920 influenza pandemic have provided a comprehensive overview of the spread of the pandemic and possible explanations for high mortality rates in Alaska, USA. Our understanding of the role of nonpharmaceutical interventions (NPIs) is limited, however. To gain an overview of various agencies’ efforts to protect communities during the pandemic, we conducted a mixed-method assessment of a large pool of digitized historical newspapers and archival materials covering Alaska’s local and territorial responses to the pandemic. The study encompassed 14 local units of Alaska that implemented NPIs during October 1918–January 1919. Analyses indicated that 8 local units avoided the outbreak by implementing NPIs and that the other 6 units controlled the spread of influenza by implementing NPIs after the virus was introduced. In addition, some Indigenous communities escaped the pandemic by implementing mandatory and voluntary restrictions. Information on the effects NPI of could guide future influenza pandemic preparedness and response.

We explored the role of black flying foxes (Pteropus alecto) in Australia as reservoirs of Borrelia bacteria. We found bats infected with 2 Borrelia haplotypes phylogenetically distinct from Lyme or relapsing fever clades. Efforts to sample black flying foxes and their ectoparasites are needed to evaluate zoonotic potential of those Borrelia lineages.

Positive laboratory results are increasingly used for Lyme disease surveillance in the United States. We found 6%–15% of persons with a positive test each year tested positive in a prior year; repeat testing frequency increased with patient age. Repeat testing of persons with previous seropositivity could affect surveillance data interpretation.

We confirmed influenza A virus (IAV) by PCR in serum from 20 cows on 3 affected dairy farms in California, USA. Our findings indicate the presence of viremia and might help explain IAV transmission dynamics and shedding patterns in cows. An understanding of those dynamics could enable development of IAV mitigation strategies.

We investigated the molecular epidemiology of Vibrio cholerae O1 in Fujian Province, China, during 2009­–2023. Sequence type (ST) 75 clonal complex has emerged continuously since 2020, and ST1480 and ST182 have dominated. ST1480 strains appear to have widespread transmission. To monitor V. cholerae evolution, continued global genomic surveillance is needed.

We report a presumptive case of melioidosis caused by an atypical Burkholderia pseudomallei serotype in an American quarter horse in north-central Florida, USA, through archived formalin-fixed paraffin-embedded specimens dating back to 2006. This case underscores the potential pathologic impact of emergent B. pseudomallei in the Gulf region of the United States.

Nine-banded armadillos (Dasypus novemcinctus) are suspected transmission sources of Hansen disease in North America. We conducted a telephone survey and chart review of patients with Hansen disease seen at a Georgia, USA, clinic during 1997–2022. Findings suggest frequent outdoor activities and armadillo contact were likely sources of exposure.

We assessed concentrations of parvovirus B19 DNA from 2 wastewater treatment plants in a Texas, USA, county with a known outbreak in 2024. Wastewater viral concentrations correlated significantly with clinical cases, demonstrating wastewater’s potential for tracking parvovirus B19 infections. Peaks in wastewater concentrations were aligned with the peak in hydrops fetalis diagnoses.

We identified a case of extensively drug-resistant (ceftriaxone- and cefixime-resistant and high-level azithromycin-resistant) Neisseria gonorrhoeae in Canada. The strain harbors the penA 60.001 allele, which includes the A311V and 23S rRNA A2059G single-nucleotide polymorphisms associated with high-level azithromycin resistance. The infection was likely acquired during travel in Cambodia.

We report 2 human Corynebacterium silvaticum infections in Germany with axillary lymphadenitis and abscess formation; in 1 case the infection likely originated from a slaughtered wild boar. This recently described member of the diphtheria toxin gene–bearing C. diphtheriae species complex might be a new zoonotic pathogen.

We detected Shuni virus in horses and ovine fetuses and Shamonda virus in a caprine fetus in South Africa. We identified a Shuni/Shamonda virus reassortant in a horse and Shuni/Caimito, Shamonda/Caimito, and Shamonda/Sango virus reassortants in Culicoides midges. Continued genomic surveillance will be needed to detect orthobunyavirus infections in Africa.

We report an outbreak of ceftriaxone-resistant Salmonella enterica serovar Typhi in Bangladesh; 47 cases were identified during April–September 2024. Isolates belonged to genotype 4.3.1.2 and harbored the bla_CTX-M-15 gene on the pCROB1 plasmid. This genotype-plasmid lineage represents a recent introduction, calling for strengthened surveillance, antimicrobial stewardship, and vaccination strategies.

Plasmodium falciparum strains lacking P. falciparum histidine-rich protein 2 (PfHRP2) and PfHRP3 threaten malaria rapid test reliability. We show that pfhrp2/pfhrp3–deleted parasites circulated in Ethiopia as early as 2009, before widespread PfHRP2-based rapid test use, and had high pfhrp3 deletion prevalence. Monitoring of pfhrp2 and of pfhrp3 deletions is needed.

Highly pathogenic avian influenza causes substantial poultry losses and zoonotic concerns globally. Duck vaccination against highly pathogenic avian influenza began in France in October 2023. Our assessment predicted that 314–756 outbreaks were averted in 2023–2024, representing a 96%–99% reduction in epizootic size, likely attributable to vaccination.

Norovirus GII.17 outbreaks in the United States increased from <10% during the 2022–23 season to 75% during the 2024–25 season, surpassing the number of GII.4 outbreaks. The norovirus season also started earlier in 2024–25 than in previous seasons. Continued norovirus surveillance is needed to detect and monitor emerging strains.

We report on a patient in China with no underlying illnesses who died of Burkholderia thailandensis infection despite timely treatment. This case challenges the perception that B. thailandensis is nonlethal or has low virulence. Increased clinical awareness and prompt diagnosis are essential for managing B. thailandensis infections and preventing fatal outcomes.

Mycoplasma phocimorsus is an identified zoonotic agent of musculoskeletal infections. Osteomyelitis developed in a patient after injury sustained while skinning a bear, and he experienced delayed diagnosis after ineffective treatments. Clinicians should use doxycycline or moxifloxacin therapy in treatment-refractory cases with exposure to seals, cats, or bears while awaiting molecular diagnostics results.

Next-generation sequencing might improve diagnosis of infective endocarditis. A case in Switzerland was initially attributed to Solobacterium moorei bacteria. Metagenomic analysis of the affected heart valve detected Streptococcus gordonii, but not S. moorei, illustrating that the results of molecular detection can vary depending on sampling time and anatomic site.

Syphilis has a wide range of possible symptoms, making it difficult to diagnose. We report a rare case of liver abscess secondary to Treponema pallidum in a man in Minnesota, USA, who had well-controlled HIV infection. This case emphasizes the importance of appropriate screening for syphilis, especially in high-risk populations.

We sequenced Leishmania tropica genomes from 8 human skin samples collected in a newly emerging focus of cutaneous leishmaniasis in the Somali region of Ethiopia. We found a variant with unique genomic signatures of drug resistance. Public health officials should use genomic surveillance to slow expansion of L. tropica.

We report a rare case of syphilitic aortitis with possible neurosyphilis in an asymptomatic 89-year-old man in Washington, DC, USA. This case highlights the need to consider emerging infectious causes of aortitis, even in patients without classic risk factors, by using multimodality imaging with confirmatory serologic and cerebrospinal fluid testing.

We describe 2 cases of Plasmodium knowlesi malaria in persons from Israel who traveled to Thailand in 2023. One patient, likely infected in northwestern Thailand, might signal geographic expansion into areas not previously associated with human infection. The infection’s rarity in travelers, diagnostic challenges, and potential severity underscore the importance of clinical awareness.

We polled infectious disease specialists about cryptococcal antigen screening for patients initiating HIV antiretroviral therapy. Of 215 respondents, 33% reported typically obtaining screening for patients with CD4 counts <200 cells/mm³ and 63% for counts <100 CD4 cells/mm³. Uncertainty about cryptococcal antigen screening benefits and recommendations suggests opportunities for education and increased screening.

Talaromycosis is a life-threatening fungal disease that primarily affects immunocompromised persons in Southeast Asia. We conducted a multicenter, case–control study recruiting participants with advanced HIV disease in Vietnam; 205 case-patients with culture-confirmed talaromycosis were matched to 405 control-patients by age, sex, and CD4 count. Occupational exposure to tropical plants (odds ratio [OR] 1.73 [95% CI 1.10–2.73]; p = 0.017) and to farmed animals (OR 2.07 [95% CI 1.20–3.55]; p = 0.009) were independent risk factors for talaromycosis. Talaromycosis risk was higher in participants from highland regions than in persons from lowland regions (p<0.05). Participants from lowland regions who had lived or traveled to highland regions had a higher risk for talaromycosis (OR 3.15 [95% CI 1.49–6.64]; p = 0.003). This study confirms the epidemiologic correlation between talaromycosis and soil exposure and demonstrates an epidemiologic link between talaromycosis and residence in or travel to highland regions of Vietnam.

Spiroplasma ixodetis has been reported to cause the rare combination of cataract and uveitis in infants. Through a retrospective analysis of available literature and additional unpublished cases, we identified 28 eyes from 18 infants from 8 countries in Europe with cataracts and intraocular inflammation. The cataracts were bilateral in 55.6%, unilateral in 44.4%, and progressive in 46.4% of patients. Granulomatous anterior uveitis was found in all infants. Presence of S. ixodetis was supported by PCR (positive in 89.3% of eyes tested), transmission electron microscopy (positive in 90% of eyes tested), or culture of aspirated lens material (positive in 87.5% of eyes tested). Treatment with macrolide antimicrobial drugs, corticosteroids, and lensectomy appeared to be effective. Two patients had a recurrence of the uveitis after lens extraction and needed prolonged treatment. To increase awareness of S. ixodetis, we suggest its inclusion with the organisms of the TORCH acronym.

During 2007–2020, we conducted a cross-sectional prevalence study among patients with acute undifferentiated febrile illness to describe the burden and long-term epidemiology of rickettsioses in Cambodia. Serum samples were collected from 10,243 participants, along with epidemiologic data, information on clinical symptoms, demographic characteristics, and risk factors. A total of 802 (7.8%) participants met the definition for acute rickettsial infection after ruling out malaria, influenza, dengue, and chikungunya; 557 (5.4%) cases were typhus, 154 (1.5%) spotted fever, and 136 (1.3%) scrub typhus. Overall seroprevalence was 18.1% (1,857/10,243). Increased age, residence in urban settings, and recent travel to forests were significantly associated with rickettsial infection. Symptoms significantly associated with infection included rash, vomiting, and skin lesions. Our results confirm the underlying burden of rickettsioses and associated risk factors in Cambodia and highlight the need for accessible diagnostics and clinical guidance that consider rickettsioses when treating persons with acute undifferentiated febrile illness.

Invasive aspergillosis (IA) caused by Aspergillus flavus remains poorly described. We retrospectively analyzed 54 cases of IA caused by A. flavus reported in France during 2012–2018. Among cases, underlying IA risk factors were malignancy, solid organ transplantation, and diabetes. Most (87%, 47/54) infections were localized, of which 33 were pleuropulmonary and 13 were ear-nose-throat (ENT) infection sites. Malignancy (70% [23/33]) and solid organ transplantation (21% [7/33]) were the main risk factors in localized pulmonary infections, and diabetes mellitus was associated with localized ENT involvement (61.5%, [8/13]). Fungal co-infections were frequent in pulmonary (36%, 12/33) but not ENT IA (0 cases). Antifungal monotherapy was prescribed in 45/50 (90%) cases, mainly voriconazole (67%, 30/45). All-cause 30-day case-fatality rates were 39.2% and 90-day rates were 47.1%, and rates varied according to risk factor, IA site, and fungal co-infections. Clinicians should remain vigilant for A. flavus and consider it in the differential diagnosis for IA.

Risk factors for developing bloodstream infections (BSIs) caused by Aerococcus bacteria remain insufficiently examined. In this nationwide case–control study in Sweden, 19 of 23 clinical microbiological laboratories identified patients who had aerococcal BSIs during 2012–2016. We compared each of those index patients with 4 controls matched for age, sex, and county of residence. Overall, 588 episodes of aerococcal BSI occurred over 39.6 million person-years, corresponding to an average incidence of 1.48/100,000 person-years (95% CI 1.37–1.60/100,000 person-years). Most infections developed in men >65 years of age. Aerococcal BSI was associated with neurologic (adjusted odds ratio 2.89 [95% CI 2.26–3.70]) and urologic (adjusted odds ratio 2.15 [95% CI 1.72—2.68]) conditions and previous hospitalization or infection treatment. Our findings support the previously observed predilection for aerococcal BSIs developing in elderly men with urinary tract disorders. Awareness of Aerococcus spp. in patients, especially elderly men, will be needed to manage invasive infections.

Tularemia, a zoonosis caused by Francisella tularensis, is endemic in Baden-Wuerttemberg, Germany. To determine tularemia epidemiology in this region, we characterized the genetic diversity of F. tularensis in human and animal isolates during 2012–2022 by using whole-genome sequencing, combined with human and veterinary surveillance data analysis. Human case numbers varied; most cases occurred in 2021 (n = 34). Arthropod bites were reported most in cases with information on animal exposure (45%, n = 43). Poisson regression confirmed a significant increase in human cases during the study period (p<0.001). No seasonal pattern was identified, but case numbers were lowest in winter. Human surveillance data often lacked exposure details. Positivity rates in animals were 5%–34%, increasing since 2017. Human isolates often clustered with hare-derived strains, although transmission routes often remain unclear. These findings emphasize the importance of combining genome sequencing with detailed epidemiologic tracing to identify infection sources and improve surveillance data.

A previous study demonstrated noninferior efficacy of 4-month rifapentine/moxifloxacin regimen for tuberculosis (TB) treatment compared with the standard regimen. We explored results among study participants with diabetes. Among 2,516 randomized participants, 181 (7.2%) had diabetes. Of 166 participants with diabetes in the microbiologically eligible analysis group, 26.3% (15/57) had unfavorable outcomes in the control regimen, 13.8% (8/58) in the rifapentine/moxifloxacin regimen, and 29.4% (15/51) in the rifapentine regimen. The difference in proportion of unfavorable outcomes between the control and rifapentine/moxifloxacin arms in the microbiologically eligible analysis group was –12.5% (95% CI –27.0% to 1.9%); the difference between the control and rifapentine arms was 3.1% (95% CI –13.8% to 20.0%). Safety outcomes were similar in the rifapentine/moxifloxacin regimen and control arms. Among participants with TB and diabetes, the rifapentine/moxifloxacin arm had fewest unfavorable outcomes and was safe. Our findings indicate that the rifapentine/moxifloxacin regimen can be used in persons with TB and diabetes.

Human ehrlichiosis is a potentially fatal tickborne disease caused by 3 species: Ehrlichia chaffeensis, E. ewingii, and E. muris eauclairensis. In the United States, 234 confirmed cases of E. ewingii ehrlichiosis were reported to the Centers for Disease Control and Prevention through the National Notifiable Diseases Surveillance System during 2013–2021; average annual incidence was 0.08 cases/1 million population. E. ewingii ehrlichiosis was reported more commonly among older, White, non-Hispanic, and male patients. Incidence and case counts generally increased yearly, except for 2020 and 2021. The highest number of cases were reported from Missouri and Arkansas. We report the geographic expansion of E. ewingii ehrlichiosis and the continued public health challenge of clarifying clinical manifestations of this infection. Clinician education will be essential to implement molecular assays to properly diagnose E. ewingii infection in patients and gain a better understanding of the epidemiology of this emerging disease.

A global increase in the incidence of invasive group A Streptococcus (iGAS) infections was observed after lifting of COVID-19 related restrictions in 2022, and type M1_UK dominated in many countries. After seasonal declines in iGAS incidence during the summer of 2023, simultaneous, rapid expansion of a previously rare emm type 3.93 was seen beginning in November, increasing to 20% of all cases in England and 60% of all cases in the Netherlands within 4 months. emm3.93 was associated with iGAS in children 6–17 years of age and with increased risk for pneumonia or pleural empyema and meningitis in both countries. No excess risk of death was identified for emm3.93 compared with other types. Genomic analysis of historic and contemporary emm3.93 isolates revealed the emergence of 3 new clades with a potentially advantageous genomic configuration. Our findings demonstrate the value of molecular surveillance, including long-read sequencing, in identifying clinical and public health threats.

Rickettsia sibirica mongolitimonae is an emerging cause of tickborne rickettsiosis. Since the bacterium was first documented as a human pathogen in 1996, a total of 69 patients with this infection have been reported in the literature. Because of the rising rate of R. sibirica mongolitimonae infection cases, we evaluated the epidemiologic and clinical features of 29 patients who had R. sibirica mongolitimonae infections confirmed during 2007–2024 at the Center for Rickettsiosis and Arthropod-Borne Diseases, the reference laboratory of San Pedro University Hospital–Center for Biomedical Research of La Rioja, Logroño, Spain. We also reviewed all cases published in the literature during 1996–2024, evaluating features of 94 cases of R. sibirica mongolitimonae infection (89 in Europe, 4 in Africa, and 1 in Asia). Clinicians should consider R. sibirica mongolitimonae as a potential causative agent of rickettsiosis, and doxycycline should be administered promptly to avoid clinical complications.

Streptococcus pneumoniae infection is considered an uncommon cause of arthritis in adults. To determine the clinical and microbiological characteristics of pneumococcal septic arthritis, we retrospectively studied a large series of cases among adult patients during the 2010–2018 conjugate vaccine era in France. We identified 110 patients (56 women, 54 men; mean age 65 years), and cases included 82 native joint infections and 28 prosthetic joint infections. Most commonly affected were the knee (50/110) and hip (25/110). Concomitant pneumococcal infections were found in 37.2% (38/102) and bacteremia in 57.3% (55/96) of patients, and underlying conditions were noted for 81.4% (83/102). Mortality rate was 9.4% (8/85). The proportion of strains not susceptible to penicillin was 29.1% (32/110). Of the 55 serotyped strains, 31 (56.4%) were covered by standard pneumococcal vaccines; however, several nonvaccine serotypes (mainly 23B, 24F, and 15A) had emerged, for which susceptibility to β-lactams was low.

The Ebola virus disease (EVD) outbreak of 2013–2016 was large, leaving in its wake an estimated 17,000 survivors in West Africa. Uveitis is one of the most common ophthalmic manifestations of EVD, but long-term follow-up in the at-risk population is lacking. We conducted a retrospective cross-sectional study of 521 EVD survivors from Sierra Leone who underwent comprehensive ophthalmic examination a median of 1,289 days, or ≈3.5 years, after discharge from Ebola treatment units. The most common ophthalmic findings were cataracts (117 eyes, 11.2%), uveitis (86 eyes, 8.3%), dry eyes (81 eyes, 7.8%), and chorioretinal scar (68 eyes, 6.5%). EVD survivors with cataracts, uveitis, optic neuropathy, and corneal scar were more likely to have vision impairment, defined as Snellen visual acuity worse than 20/50. Results of our study highlight the need for ongoing vision care in EVD survivors.

Congregate homeless shelters are disproportionately affected by infectious disease outbreaks. We describe enterovirus epidemiology across 23 adult and family shelters in King County, Washington, USA, during October 2019–May 2021, by using repeated cross-sectional respiratory illness and environmental surveillance and viral genome sequencing. Among 3,281 participants >3 months of age, we identified coxsackievirus A21 (CVA21) in 39 adult residents (3.0% [95% CI 1.9%–4.8%] detection) across 7 shelters during October 2019–February 2020. We identified enterovirus D68 (EV-D68) in 5 adult residents in 2 shelters during October–November 2019. Of 812 environmental samples, 1 was EV-D68–positive and 5 were CVA21–positive. Other enteroviruses detected among residents, but not in environmental samples, included coxsackievirus A6/A4 in 3 children. No enteroviruses were detected during April 2020–May 2021. Phylogenetically clustered CVA21 and EV-D68 cases occurred in some shelters. Some shelters also hosted multiple CVA21 lineages.

Mycobacterium abscessus infection is challenging to treat. Extrapulmonary M. abscessus infections (EP-MAB) are less common than pulmonary M. abscessus infections. To evaluate treatment regimens, we retrospectively analyzed consecutive microbiologically confirmed EP-MAB cases diagnosed in France during 2012–2020. We studied 45 patients with EP-MAB, including 14 bone and joint infections, 10 skin and soft tissue infections, and 8 lymph node infections. Most (62%) patients had no reported immunodeficiency. In 27 patients, EP-MAB followed healthcare-associated (44%) or environmental (16%) injuries. Of the 45 isolates, 25 were subspecies abscessus, 10 bolletii, and 9 massiliense; 1 was unidentified. Cure was achieved for 36 (80%) patients who received a median antimicrobial regimen of 6 months; 22 (55%) also underwent surgery. Four patients died, and 5 were unavailable for follow-up. EP-MAB predominantly affects immunocompetent patients after an injury; outcomes are favorable. We propose a >6-month regimen of antimicrobial therapy with consideration for surgery and regular patient reassessment.

Pasteurella spp. can cause fatal zoonotic infections in humans. We performed a multicenter study to investigate the prevalence and clinical features of Pasteurella infections in South Korea during 2018‒2022. We also conducted a collaborative systematic review and meta-analysis of the global burden of Pasteurella bacteremia. The study included 283 cases found an increasing trend in Pasteurella infections. Blood cultures were positive in 8/35 (22.9%) cases sampled, for overall bacteremia-associated rate of 2.8% (8/283). Aging was a significant risk factor for bacteremia (odds ratio 1.05 [95% CI 1.01–1.10]), according to multivariate analyses. For the meta-analysis, we included a total of 2,012 cases from 10 studies. The pooled prevalence of bacteremia was 12.4% (95% CI 7.3%–18.6%) and of mortality 8.4% (95% CI 2.7%–16.5%). Our findings reflect the need for greater understanding of the increase in Pasteurella infections and the global burden of Pasteurella bacteremia to determine appropriate case management.

We investigated differences in risk factors and preventive behaviors by age and sex among persons with reported Lyme disease in Ontario, Canada, during 2015–2022. Incidence rates peaked among children 5–9 and adults 50–79 years of age. Median age was higher for female than male case-patients (54 vs. 51 years). Male case-patients reported more activity in wooded and tall grass areas than did female case-patients; fewer male case-patients reported sharing living space with outdoor-exposed companion animals. As age increased, more case-patients reported activity in blacklegged tick habitats, exposure to ticks, and wearing adequate clothing, but fewer reported sharing living space with outdoor-exposed companion animals. Adoption of preventive behaviors was relatively low and did not differ by sex. Male case-patients, children 5–9 years of age and their parents or caregivers, and adults >59 years of age represent populations that would benefit from tailored public health messaging on Lyme disease prevention.

We conducted a prospective study of 159 cases of Streptococcus dysgalactiae subspecies equisimilis (SDSE) bacteremia in 157 patients at 2 hospitals in Finland during November 2015–November 2019. Cellulitis was associated with nonsevere disease (p = 0.008); necrotizing fasciitis was associated with severe disease (p = 0.004). Fifty percent of patients had >1 clinical characteristic associated with risk for death. The case-fatality rate was 6%, and 7% of patients were treated in an intensive care unit. Blood leukocyte counts on days 2 (p = 0.032) and 3 (p = 0.020) and C-reactive protein levels on days 3 (p = 0.030) and 4 (p = 0.009) after admission were predictors of severe disease. The Pitt bacteremia score was an accurate predictor of death. Using the Pitt bacteremia score, leukocyte counts, and CRP responses during initial treatment can improve treatment strategies and survival for patients with SDSE.

Evidence on mortality rates and causes of death associated with extrapulmonary nontuberculous mycobacteria (NTM) infection is limited. This nationwide register-based study in Denmark used diagnostic codes to match adult patients with extrapulmonary NTM infection 1:4 to controls. During 2000–2017, we identified 485 patients, who had significantly more comorbidities than controls. The 5-year mortality rate for patients was 26.8% (95% CI 23.1%–31.0%) and for controls, 10.9% (95% CI 9.6%–12.4%). The median age at death was 76 (interquartile range 63–85) years for patients and 84 (interquartile range 73–90) years for controls. The adjusted hazard rate of death for patients was 1.34 (95% CI 1.10–1.63; p = 0.004). Patients and controls mainly died of cardiovascular disease and solid malignant neoplasms. Hematologic malignancies and HIV were more frequently causes of death in patients. Mortality rates are substantial among patients with extrapulmonary NTM infection, predominantly caused by underlying conditions.

Human infections with Corynebacterium diphtheriae species complex (CdSC) bacteria were rare in French Guiana until 2016, when the number of cases diagnosed increased. We conducted an epidemiologic, multicenter, retrospective study of all human CdSC infections diagnosed in French Guiana during January 1, 2016–December 31, 2021. A total of 64 infectious episodes were observed in 60 patients; 61 infections were caused by C. diphtheriae and 3 by C. ulcerans. Estimated incidence increased from 0.7 cases/100,000 population in 2016 to 7.7 cases/100,000 population in 2021. The mean patient age was 30.4 (+23.7) years, and male-to-female ratio was 1.7:1 (38/22). Of the 61 C. diphtheriae isolates, 5 tested positive for the diphtheria toxin gene, and all results were negative by Elek test; 95% (61/64) of cases were cutaneous, including the C. ulcerans cases. The increase in reported human infections underscores the need to raise awareness among frontline healthcare practitioners to improve prevention.

Archaea represent a separate domain of life, next to bacteria and eukarya. As components of the human microbiome, archaea have been associated with various diseases, including periodontitis, endodontic infections, small intestinal bacterial overgrowth, and urogenital tract infections. Archaea are generally considered nonpathogenic; the reasons are speculative because of limited knowledge and gene annotation challenges. Nevertheless, archaeal syntrophic principles that shape global microbial networks aid both archaea and potentially pathogenic bacteria. Evaluating archaea interactions remains challenging, requiring clinical studies on inflammatory potential and the effects of archaeal metabolism. Establishing a culture collection is crucial for investigating archaea functions within the human microbiome, which could improve health outcomes in infectious diseases. We summarize potential reasons for archaeal nonpathogenicity, assess the association with infectious diseases in humans, and discuss the necessary experimental steps to enable mechanistic studies involving archaea.