Articles from Emerging Infectious Diseases

Chagas disease, caused by Trypanosoma cruzi parasites, is considered endemic to 21 countries in the Americas, excluding the United States. However, increasing evidence of T. cruzi parasites in the United States in triatomine insects, domestic animals, wildlife, and humans challenges that nonendemic label. Several triatomine species are common in the southern United States, where they transmit T. cruzi and invade human dwellings. Wildlife, captive animals, and companion animals, especially dogs, are commonly infected with T. cruzi parasites in this region and serve as reservoirs. Autochthonous human cases have been reported in 8 states, most notably in Texas. Labeling the United States as non–Chagas disease–endemic perpetuates low awareness and underreporting. Classification of Chagas disease as endemic, in particular as hypoendemic, to the United States could improve surveillance, research, and public health responses. Acknowledging the endemicity of Chagas disease in the United States is crucial for achieving global health goals.

The complexity of rickettsial serodiagnostics during acute illness has limited clinical characterization in Africa. We used archived samples from sepsis (n = 259) and acute febrile illness (n = 70) cohorts in Uganda to identify spotted fever and typhus group rickettsiae by using immunofluorescence assay and clinically validated rRNA reverse transcription PCR (RT-PCR). Among 329 participants, 10.0% had rickettsial infections (n = 33; n = 20 identified with immunofluorescence assay and n = 13 by RT-PCR). Serum rRNA RT-PCR was 75.0% (95% CI 42.8–94.5%) sensitive and 91.2% (95% CI 85.8–95.1%) specific. Thrombocytopenia was more common among patients with rickettsial infections than with other nonmalarial infections (adjusted odds ratio 3.7; p = 0.003). No participants were on a tetracycline antimicrobial drug at admission. rRNA RT-PCR is a promising diagnostic strategy for identifying acute rickettsial infections. Doxycycline should be included in empiric antimicrobial drug regimens for nonmalarial febrile illness in this region.

We describe 7,421 chikungunya hospitalizations in Brazil covered by the country’s unified health system during 2014–2024. Most (43.2%) hospitalizations occurred in 2016 and 2017, reaching 0.72 (95% CI 0.69–0.76) hospitalizations/100,000 population in 2016. Hospitalizations were more frequent among persons who were female (55.8%), identifying as brown or black (63.5%), and 1–19 years of age (31.4%). Intensive care unit admissions occurred in 1.4% of cases, predominantly among children <5 and adults >85 years of age. The overall in-hospital case-fatality rate was 1.1%, which increased substantially with age, reaching 11.5% among patients >90 years of age and 14.1% among men 85–89 years of age. Patients admitted to the intensive care unit had a case-fatality rate of 21.1%. The total cost of chikungunya hospitalizations was US $560,746 (US $76.26 per patient). Our findings provide insights for surveillance of the most severe chikungunya cases.

Crimean-Congo hemorrhagic fever (CCHF) is an emerging tickborne disease and a World Health Organization priority. Although humans are accidental hosts, infection can lead to hemorrhagic fever with a high fatality rate. Domestic animals play a critical role in disease transmission, but infected animals do not show clinical signs and viremia is short; thus, CCHF virus (CCHFV) infections can remain unobserved. During 2017–2019, we conducted 2 sequential observational studies followed by a multisite randomized controlled trial to determine spatial-temporal patterns and quantify drivers for CCHFV exposure in a natural host (sheep) in a CCHF-endemic area of Bulgaria. We found high-risk areas embedded in endemic regions. Animal characteristics were not correlated with seropositivity; however, a seasonality effect was observed, suggesting sampling time was a potential confounder. Force of infection varied across farms and over time. CCHFV transmission heterogeneity among farms is driven by preventive measures used to reduce exposure to ticks.

Candida auris transmission surged in long-term acute-care hospitals (LTACHs) in Orange County, California, USA, during the COVID-19 pandemic. This study describes the effect of COVID-19 on C. auris transmission by estimating the probability of patient colonization in LTACHs across 5 epidemiologic time periods. Patients had the highest probability of developing new skin colonization during the first COVID-19 wave, with a cumulative incidence of 22.5% (95% CI 18.5­–26.6) after a 30-day stay. Once the initial COVID-19 waves abated, a reduction in cumulative incidence of C. auris colonization was observed concurrently with persistent high prevalence, indicating that within-facility transmission can be reduced with proper infection prevention and control practices. Admission screenings and point prevalence surveys provided a wealth of data that guided public health recommendations and supported the objectives of both public health professionals and LTACHs for monitoring facility transmission dynamics and guiding decision making.

Lyme disease is the most common vectorborne disease in the United States. Evidence suggests that persons from racial and ethnic minority groups experience more severe disease. We used a claims-based algorithm on data from 16 jurisdictions with high Lyme disease incidence to identify cases among 4 populations: Medicaid beneficiaries <18 and >19 years of age, and Medicare fee-for-service beneficiaries <65 and >65 years of age. We calculated the prevalence of disseminated disease, hospitalization, and other clinical and epidemiologic parameters by race and ethnicity. We found that non-White persons were more likely than White persons to be female, hospitalized at diagnosis, diagnosed outside of primary care, diagnosed outside of the peak months for Lyme disease transmission, and have disseminated disease. Those data illustrate differences in Lyme disease by race and ethnicity and suggest possible differences across other sociodemographic characteristics. Additional prevention methods are needed to reduce differences in Lyme disease recognition and severity.

Piroplasmid parasites such as Theileria luwenshuni protozoa pose a global threat to both animal and human health. However, human theileriosis remains underexplored compared to infections caused by Plasmodium and Babesia species parasites. We investigated potential hemoparasite infections among 1,721 persons with fever, anemia, or both in Yunnan Province, China. Molecular detection identified 13 cases positive for T. luwenshuni protozoa, of which 5 patients were further confirmed by Western blot antibody analysis. We also identified 6 babesiosis cases, 3 infections with B. microti and 3 with novel Babesia spp. Subsequent vector and host investigations in the vicinity of the index cases revealed T. luwenshuni protozoa in 1 tick and 53 livestock animals. Of note, 3.3% combined vector-host samples tested positive for genetically diverse Babesia species. Our findings highlight the endemic circulation of T. luwenshuni and Babesia spp. parasites in southwest China, underscoring their importance as emerging public health concerns.

The fungus Trichosporon asahii has emerged as a cause of nosocomial infections, particularly in immunocompromised patients. Given its rising prevalence, information on its genetic diversity and transmission dynamics is urgently needed. We developed a microsatellite typing tool to investigate the genetic relatedness of T. asahii isolates. We selected 6 microsatellite markers from nanopore long-read sequencing of the T. asahii type-strain CBS 2479. We applied those markers to 111 clinical and environmental isolates; microsatellite typing showed high variability among isolates (11–37 alleles per marker) and identified 71 genotypes with strong discriminatory power (Simpson index of 0.9793). We applied the microsatellite typing method to T. asahii isolates from South America and identified multiple nosocomial transmission events from hospitals in Brazil, including clusters spanning more than a decade. The panel we developed offers high reproducibility and specificity, making it an effective tool for tracking outbreaks and determining the public health effects of T. asahii infections.

Cat-transmitted sporotrichosis caused by Sporothrix brasiliensis is an emerging zoonosis in Latin America. Because treatment of feline sporotrichosis is often not effective, we sought to determine whether treatment failure results from S. brasiliensis strains that have existing elevated MICs for itraconazole, the primary treatment for this disease. During 2021–2023 at the triple border region of Brazil, Paraguay, and Argentina, 108 S. brasiliensis strains were isolated from felines before antifungal treatment. The main clinical manifestation was cutaneous disseminated sporotrichosis (61%), which was the only form resulting in sporotrichosis-induced deaths (61%). We conducted antifungal susceptibility testing for 9 antifungal compounds, evaluating for both mycelial and yeast phases. MIC levels were low for most antifungal agents but were higher in the mycelial phase than in the yeast phase, especially for voriconazole and isavuconazole. We conclude that the varying clinical manifestations of sporotrichosis and large differences in mortality rates were not caused by elevated itraconazole MICs.

The human-infecting parasite Strongyloides fuelleborni subspecies kellyi has been reported from the island of New Guinea. We analyzed fecal DNA extracts (n = 164) from 19 infants in Papua New Guinea by using Strongyloides real-time PCR and undertook metabarcoding of cox1 and 18S rRNA hypervariable regions I and IV loci. Eight infants were infected with Strongyloides spp.; 7 were infected with S. fuelleborni subsp. fuelleborni and 1 with a Strongyloides sp. previously misattributed to S. fuelleborni subsp. kellyi. Phylogenetic and haplotyping analyses indicated S. fuelleborni in Papua New Guinea belongs to the Indochina subclade of S. fuelleborni subsp. fuelleborni and is not a unique subspecies. We report molecular evidence of S. fuelleborni subsp. fuelleborni infection in humans in the Pacific. Our findings also demonstrate the potential co-existence of an undescribed human-infecting Strongyloides sp. on the island of New Guinea, indicating a need for renewed clinical and epidemiologic investigations into infant strongyloidiasis.

We identified 4 cases of presumptive autochthonous melioidosis during 1983–2024 in Georgia, USA. Epidemiologic investigation identified no recent international travel before illness; all cases were geographically linked, and 3 patients became ill after a severe weather event. Bioinformatic analyses revealed Burkholderia pseudomallei genome sequences were highly related, suggesting a shared exposure.

We determined CYP2D6*4 and CYP2D6* genotypes and metabolizer phenotypes in 96 patients with suspected malaria in Venezuela and found intermediate or poor metabolizer phenotypes in ≈25% of cases. Nine of 44 malaria patients had Plasmodium vivax recurrence. Public health authorities should evaluate the benefits of increasing total doses of primaquine for treatment.

We describe a case of a gastric submucosal tumor in a patient in South Korea infected with Dioctophyme renale roundworm. The patient had a history of consuming raw freshwater fish. Molecular and morphologic analyses confirmed D. renale Infection. Genetic testing should be used to diagnose rare parasitic infections with unusual clinical manifestations.

In October 2024, twelve primates from 4 species died of sepsis at the Hong Kong Zoological and Botanical Gardens. Postmortem examinations and microbiological analyses confirmed Burkholderia pseudomallei infection. Phylogenetic analysis revealed a clonal sequence type 46 strain with minimal variation, signifying a single source. This outbreak highlights melioidosis risk in zoo settings.

We performed molecular characterization of Orientia tsutsugamushi on DNA sequences from 5 patients from Bhutan with scrub typhus. In the 56 kDa gene, all isolates aligned with those from other Asia countries, including Nepal, India, Thailand, and Taiwan. High serum IgM titers correlated with PCR positivity in acutely ill patients.

We describe isolation and characterization of a novel henipavirus, designated Salt Gully virus, from the urine of pteropid bats in Australia. We noted the virus to be most closely related to Angavokely virus, not reliant on ephrin receptors for cell entry, and of unknown risk for human disease.

In 2022, a Sudan Ebola virus outbreak was confirmed in Uganda. Within 1 month of the outbreak’s onset, we developed an individual-based modeling platform to estimate the unfolding outbreak’s burden of cases and deaths, as well as its duration, using different scenarios. Modeled projections were within the range of observed cases.

The emerging zoonotic nematode Angiostrongylus cantonensis causes severe neural angiostrongyliasis in both humans and animals. The parasite has been reported in Spain. We detected A. cantonensis in rats and gastropods from the Campania region, southern Italy, demonstrating its broad distribution on the southern coast of Europe.

We report 4 cases of equine cutaneous leishmaniasis caused by Leishmania martiniquensis in Czech Republic and Austria, outside the known endemic range of leishmaniases. The parasite should be considered as a potential cause of cutaneous lesions in horses; the risk for zoonotic transmission to immunocompromised humans is anticipated throughout central Europe.

Plasmodium falciparum infection was diagnosed in a 3-month-old baby in Portugal by optical microscopy. The mother had had malaria in Angola 13 months earlier, before she emigrated to Portugal. She remained asymptomatic throughout and after pregnancy. We confirmed the diagnosis of an imported malaria case and congenital transmission using molecular techniques.

We performed monkeypox virus genome sequencing on clinical samples from Liberia, yielding 5 clade IIa genomes. Our analysis found no evidence of sustained human-to-human transmission, suggesting independent zoonotic spillovers from a diverse viral lineage. Public health officials should continue monitoring and sequencing efforts to identify emerging monkeypox virus lineages.

The rat lungworm, Angiostrongylus cantonensis, is an invasive, zoonotic parasite that can cause severe disease in humans. We collected A. cantonensis larvae from 2 host species, invasive apple and mystery snails, from bodies of water in Georgia, USA. Recreational water users should avoid ingesting potentially infected hosts, aquatic vegetation, and water.

Mosquitoborne diseases are a growing threat to public health worldwide. Human dirofilariasis, caused by the nematode Dirofilaria repens and transmitted by mosquitoes from various genera, has recently expanded into new areas of Europe. In this article, we report molecularly confirmed autochthonous human D. repens infections in Estonia.

The Angiostrongylus cantonensis rat lungworm is a zoonotic nematode that infects several rat species. This nematode causes eosinophilic meningitis and meningoencephalitis in humans and other accidental hosts. We found a 20% prevalence of A. cantonensis lungworms in black rats from a zoo facility in Houston, Texas, USA.

We report a case of acute babesiosis in a splenectomized 63-year-old man in Siberia, Russia. We confirmed the causative agent, Babesia venatorum, by PCR. Our study demonstrated a change in the structure of the parasite population, from single parasite invasion of erythrocytes to multioccupancy, without an increase in parasitemia level.

Treatment of actinomycotic mycetoma with joint involvement is challenging. We present a patient in India with actinomycotic mycetoma who reached complete cure and remission after linezolid and meropenem treatment with a 2-year posttreatment follow-up. Clinicians should use novel drug regimens based on subspecies variations of Nocardia and regional drug susceptibility patterns to guide therapy.

We present a case of subarachnoid neurocysticercosis caused by Taenia crassiceps in an elderly woman in Slovenia with no underlying disease or immunosuppressive treatment. The parasite was identified by 12S rDNA PCR and sequencing. Despite prolonged therapy with albendazole and praziquantel, the disease recurred after treatment was discontinued.

Prevalence of tick-borne encephalitis (TBE) is increasing in much of Europe. In May 2024, an autochthonous pediatric case of TBE was diagnosed in a 6-year-old girl in Belgium. Clinicians should recognize the symptoms and signs of TBE infections and consider this disease in patients with unexplained neurologic symptoms, regardless of travel history.

We describe New World screwworm (Cochliomyia hominivorax) infestation in 2 injured mountain tapirs (Tapirus pinchaque) from a protected area in the Central Andes, Colombia. Screwworms were not a known threat to mountain tapirs. Community outreach is needed to raise awareness on effects of this parasite on humans, domestic animals, and wildlife.

The complexity of rickettsial serodiagnostics during acute illness has limited clinical characterization in Africa. We used archived samples from sepsis (n = 259) and acute febrile illness (n = 70) cohorts in Uganda to identify spotted fever and typhus group rickettsiae by using immunofluorescence assay and clinically validated rRNA reverse transcription PCR (RT-PCR). Among 329 participants, 10.0% had rickettsial infections (n = 33; n = 20 identified with immunofluorescence assay and n = 13 by RT-PCR). Serum rRNA RT-PCR was 75.0% (95% CI 42.8–94.5%) sensitive and 91.2% (95% CI 85.8–95.1%) specific. Thrombocytopenia was more common among patients with rickettsial infections than with other nonmalarial infections (adjusted odds ratio 3.7; p = 0.003). No participants were on a tetracycline antimicrobial drug at admission. rRNA RT-PCR is a promising diagnostic strategy for identifying acute rickettsial infections. Doxycycline should be included in empiric antimicrobial drug regimens for nonmalarial febrile illness in this region.

Prevalence of emerging fungal infections is increasing, particularly among immunocompromised persons, children, and older persons. We report 108 cases of Scheffersomyces spartinae infection in pediatric patients from Karachi and other cities in Pakistan, of which 107 were identified from blood cultures. Cultures were initially misidentified as Clavispora lusitaniae by a biochemical assay before speciation as S. spartinae by whole-genome sequencing. All isolates were from children <12 years of age, and >69% were from children <1 month of age. Isolates were genetically distinct across regions of Pakistan; however, genetic diversity was low in isolates from patients in Karachi and nearby Nawabshah and had median differences of just 9 pairwise nucleotide variants. This study demonstrates S. spartinae is a potentially emerging pathogen in neonates and young infants in Pakistan. The findings highlight the limitations of phenotypic identification for detecting emerging fungal infections and underscore the value of molecular identification approaches.

Mpox was first identified against the backdrop of the smallpox eradication campaign. Monkeypox virus (MPXV), the causative agent of mpox, has been maintained in animal reservoirs in the forested regions of West and Central Africa as 2 distinct clades; clade I has historically caused more severe infection in Central Africa than clade II, historically found in West Africa. However, rapid reemergence and spread of both MPXV clades through novel routes of transmission have challenged the known characteristics of mpox. We summarize mpox demographic distribution, clinical severity, and case-fatality rates attributed to genetically distinct MPXV subclades and focus on MPXV clade Ib, the more recently identified subclade. Broad worldwide assistance will be necessary to halt the spread of both MPXV clades within mpox endemic and nonendemic regions to prevent future outbreaks.

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.