Articles from Emerging Infectious Diseases

Reemergence of Oropouche fever in Brazil raises concerns about potential risks for infection in pregnancy. We describe a case series of Oropouche fever in pregnant women and their neonates in Espírito Santo State, Brazil, in 2024. Of 73 pregnancies, 15 pregnancies concluded by the end of the study period; of those, 14 resulted in live births and 1 in spontaneous abortion. Placental reverse transcription PCR tests were positive for Oropouche virus RNA in 5 infections in the third trimester. Two infections occurred in the first trimester, resulting in 1 spontaneous abortion and 1 live birth with corpus callosum dysgenesis. Of 13 infections that occurred in the third trimester, 1 showed possible intrapartum transmission with clinical manifestations in the neonate, whereas the others were asymptomatic. We found no anomalies in third-trimester infections. These findings suggest possible vertical transmission of Oropouche virus and a potential link with spontaneous abortion or malformation.

The clinical characteristics of Alistipes bacteremia remain insufficiently understood. We retrospectively analyzed 13 cases of Alistipes bacteremia at a tertiary care center in Japan. Of the 13 patients, 7 were male and 6 female; 10 were >65 years of age. Of 9 patients with comorbidities, 7 had solid tumors or hematological malignancies and 11 had gastrointestinal symptoms. Isolates identified were Alistipes finegoldii in 4 cases, A. onderdonkii in 4, A. putredinis in 3, A. indistinctus in 2, and A. ihumii in 1. Ten strains exhibited low MICs against β-lactam/β-lactamase inhibitors and metronidazole. We observed high MICs against penicillin, ceftriaxone, and minocycline. Several strains harbored antimicrobial resistance genes, including adeF, tet(Q), cfxA3, cfxA4, and ermG. Twelve patients received β-lactam/β-lactamase inhibitors; 2 patients with solid tumors experienced septic shock and died. Alistipes bacteria can translocate from the gastrointestinal tract into the bloodstream, particularly in cases of inflammation, obstruction, or perforation, leading to severe infections.

The erythema migrans (EM) skin lesion is the most common clinical manifestation of Lyme borreliosis. Information about EM in Lyme borreliosis reinfection is limited. Of the 12,384 cases with diagnosed EM at an outpatient clinic during 1990–2014 in Slovenia, 1,962 (15.8%) cases occurred in patients who were treated previously for Lyme borreliosis, including 1,849 (94.2%) who had previously had EM. The percentage of reinfected patients who sought care with disseminated Lyme borreliosis at the time of reinfection, as manifested by multiple EM skin lesions, was significantly lower than for EM patients with no history of Lyme borreliosis (5.5% [108/1,962] vs. 7.4% [769/10,427]; p = 0.002). None of the clinical manifestations of Lyme borreliosis in Europe will completely protect against EM developing in patients in the future. The reoccurrence of Lyme borreliosis manifested by multiple EM lesions is significantly less likely than for patients with no history of Lyme borreliosis.

Estimating the number of illnesses caused by foodborne pathogens is critical for allocating resources and prioritizing interventions. We estimated the number of illnesses, hospitalizations, and deaths in the United States caused by 7 major foodborne pathogens by using surveillance data and other sources, adjusted for underreporting and underdiagnosis. Campylobacter spp., Clostridium perfringens, invasive Listeria monocytogenes, norovirus, nontyphoidal Salmonella serotypes, and Shiga toxin–producing Escherichia coli caused ≈9.9 million (90% credible interval [CrI] 5.9–15.4 million) domestically acquired foodborne illnesses in 2019. Together with Toxoplasma gondii, those pathogens caused 53,300 (90% CrI 35,700–74,500) hospitalizations and 931 (90% CrI 530‒1,460) deaths. Norovirus caused most illnesses (≈5.5 million illnesses, 22,400 hospitalizations), followed by Campylobacter spp. (1.9 million illnesses, 13,000 hospitalizations) and nontyphoidal Salmonella serotypes (1.3 million illnesses, 12,500 hospitalizations). Salmonella infection was the leading cause of death (n = 238). Foodborne illness estimates can inform policy and direct food safety interventions that reduce those illnesses.

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.

Forest changes, human population dynamics, and meteorologic conditions have been associated with zoonotic Ebolavirus spillover into humans. High-resolution spatial data for those variables can be used to produce estimates of spillover potential and assess possible annual changes. We developed a model of Ebolavirus spillover during 2001–2021, accounting for variables measured across multiple spatial and temporal scales. We estimated the annual relative odds of Ebolavirus spillover during 2021 and 2022. The highest relative spillover odds estimates occurred in patches that closely followed the spatial distribution of forest loss and fragmentation. Regions throughout equatorial Africa had increased spillover estimates related to changes in forests and human populations. Spillover events in 2022 occurred in locations in the top 0.1% of overall spillover odds estimates or where estimates increased from 2021 to 2022. This model can be used to preemptively target surveillance to identify outbreaks, mitigate disease spread, and educate the public on risk factors for infection.

Viral encephalitis is often underreported and undiagnosed. To understand the potential causes of viral encephalitis in the state of Montana, USA, we examined the relative incidence of human infections for the California serogroup (CSG) of Orthobunyaviruses by screening random convenience serum samples obtained from different hospitals across Montana. We initially screened deidentified samples for neutralizing antibodies against Jamestown Canyon virus (JCV), a CSG virus that has caused encephalitis in Montana. We then analyzed JCV-positive samples for neutralization of other CSG viruses, and detected neutralizing antibodies against La Crosse virus, California encephalitis virus, and Trivittatus virus. We also found a high level of cross-reactivity, particularly between JCV and California encephalitis virus. Our findings indicate that the relative CSG virus infection rates in humans are quite high, between 21% and 40%. Clinicians should consider CSG viruses in differential diagnosis for cases of encephalitis of unknown etiology in Montana.

Estimates of COVID-19–related healthcare costs are key to health system planning, but attributable cost data remain limited. We characterized healthcare costs attributable to COVID-19 through a population-based matched cohort study in Ontario, Canada, by using health administrative data. We matched SARS-CoV-2–positive persons from 2020 to unexposed historical control persons from 2016–2018. We estimated phase-based and survival-adjusted COVID-19–attributable healthcare costs from the health system perspective. We matched 159,817 persons. Mean (95% CI) attributable 10-day costs per person were $1 ($–4 to $6) preindex, $240 ($231–$249) during acute care, $18 ($14–$21) in postacute phases, $3,928 ($3,471–$4,384) in the terminal phase for early deaths, and $1,781 ($1,182–$2,380) for late deaths. Mean cumulative survival-adjusted cost at 360 days was $2,553 ($2,348–$2,756) per person. SARS-CoV-2 infection is associated with substantial long-term healthcare costs, consistent with understanding of post-COVID condition. Determining phase-specific costs can inform budget and pandemic planning.

Oz virus (OZV) was isolated from an Amblyomma tick in Japan and shown to cause lethal viral myocarditis in humans. However, the natural reservoirs and the distribution of OZV remain unknown. We describe epidemiologic studies conducted by using serum samples collected from mammals throughout Japan. The results showed that 27.5% of wild boars, 56.1% of Sika deer, 19.6% of Japanese macaques, and 51.0% of Asian black bears were positive for virus-neutralizing antibodies against OZV. Approximately 2.8% of dogs and 1.0% of cats also were seropositive. OZV RNA was not detected in any of the examined animal serum samples. Most seropositive animals were distributed in central and western Japan. OZV infects a wide range of animal species, including companion animals and nonhuman primates, and is distributed through central and western Japan, suggesting that further countermeasures are required to prevent this tickborne zoonotic infection.

Shiga toxin–producing Escherichia coli (STEC) infection can cause potentially fatal hemolytic uremic syndrome (HUS). To determine epidemiologic and bacterial genomic factors associated with HUS, we conducted a retrospective case–control study with 108 HUS cases and 416 unmatched controls (non-HUS) selected among STEC notifications in Ireland during 2017–2020. We combined routinely collected epidemiologic data on STEC notifications with genomewide association study findings and used logistic regression to estimate adjusted odds ratios. Our findings reaffirmed known risk factors, such as young age (0–9 years) and presence of specific stx genes or gene combinations (stx2a; stx1a + stx2a; stx1a + stx2c), and additionally suggest that having outbreak-associated infection, residence within the East region of Ireland, and the combined presence of both ygiW and group_5720 or both pfkA and fieF genes are potentially associated with developing HUS. Our findings could improve early identification of high-risk STEC infections and help guide enhanced surveillance and public health management.

Herpes B virus (B virus) is an enigmatic zoonotic virus that has caused severe neurologic symptoms in humans exposed to captive macaques used for experimentation. We examined 864 wild long-tailed macaques from 22 locations across Thailand for B virus infection. All 22 macaque populations tested positive for B virus antibodies; seropositivity ranged from 25% to 100%. B virus shedding was detected in 9 (1.04%) oral swab samples by using quantitative PCR of the virus UL29 gene. We phylogenetically analyzed partial genome sequences of B virus (US5-US6 genes) from 6 of the PCR-positive samples. All 6 sequences were clustered in clade II, which includes B virus strains from rhesus, Japanese, and long-tailed macaques, suggesting co-evolution of B virus with macaques. Continued surveillance and sequencing of B virus in macaque populations will be needed to prevent B virus transmission to humans and to develop appropriate vaccines to prevent human B virus infections.

During 2023–2024, highly pathogenic avian influenza A(H5N1) viruses from clade 2.3.2.1c caused human infections in Cambodia and from clade 2.3.4.4b caused human infections in the Americas. We assessed the susceptibility of those viruses to approved and investigational antiviral drugs. Except for 2 viruses isolated from Cambodia, all viruses were susceptible to M2 ion channel-blockers in cell culture-based assays. In the neuraminidase inhibition assay, all viruses displayed susceptibility to neuraminidase inhibitor antiviral drugs oseltamivir, zanamivir, peramivir, laninamivir, and AV5080. Oseltamivir was ≈4-fold less potent at inhibiting the neuraminidase activity of clade 2.3.4.4b than clade 2.3.2.1c viruses. All viruses were susceptible to polymerase inhibitors baloxavir and tivoxavir and to polymerase basic 2 inhibitor pimodivir with 50% effective concentrations in low nanomolar ranges. Because drug-resistant viruses can emerge spontaneously or by reassortment, close monitoring of antiviral susceptibility of H5N1 viruses collected from animals and humans by using sequence-based analysis supplemented with phenotypic testing is essential.

Carbapenem-resistant and virulence plasmid–harboring Klebsiella pneumoniae (pVir-CRKP) has emerged and spread globally, yet clinical investigations from the United States remain limited. We conducted a genomic analysis of 884 unique carbapenem-resistant K. pneumoniae isolates from a multicenter US cohort and identified 6 pVir-CRKP isolates, including 2 sequence type (ST) 23, 2 ST893, and 2 ST11 isolates. Patients infected with pVir-CRKP experienced high Pitt bacteremia scores and a 33% 30-day mortality rate. The pVir-CRKP isolates exhibited significant sequence variation in virulence genes and plasmids, along with differences in mucoviscosity, capsule production, survival in normal human serum, resistance to killing by human polymorphonuclear neutrophils, and in vivo pathogenicity. Phylogenetic analyses showed that most pVir-CRKP isolates were genetically similar to strains reported from other global regions. The emergence of pVir-CRKP with higher virulence potential and carbapenem resistance in the United States than the predominant carbapenem-resistant K. pneumoniae clone underscores the need for active global surveillance.

Prion diseases, including chronic wasting disease (CWD), are caused by prions, which are misfolded aggregates of normal cellular prion protein. Prions possess many characteristics that distinguish them from conventional pathogens, in particular, an extraordinary recalcitrance to inactivation and a propensity to avidly bind to surfaces. In middle to late stages of CWD, prions begin accumulating in cervid muscle tissues. Those features collectively create scenarios in which occupational hazards arise for workers processing venison and pose risks to consumers through direct prion exposure through ingestion and cross-contamination of food products. In this study, we demonstrate that steel and plastic surfaces used in venison processing can be directly contaminated with CWD prions and that cross-contamination of CWD-negative venison can occur from equipment that had previously been used with CWD-positive venison. We also show that several decontaminant solutions (commercial bleach and potassium peroxymonosulfate) are efficacious for prion inactivation on those same surfaces.

Salmonella enterica bacteria are a leading cause of foodborne illness in the United States; however, most Salmonella illnesses are not associated with known outbreaks, and predicting the source of sporadic illnesses remains a challenge. We used a supervised random forest model to determine the most likely sources responsible for human salmonellosis cases in the United States. We trained the model by using whole-genome multilocus sequence typing data from 18,661 Salmonella isolates from collected single food sources and used feature selection to determine the subset of loci most influential for prediction. The overall out-of-bag accuracy of the trained model was 91%; the highest prediction accuracy was for chicken (97%). We applied the trained model to 6,470 isolates from humans with unknown exposure to predict the source of infection. Our model predicted that >33% of the human-derived Salmonella isolates originated from chicken and 27% were from vegetables.

We report an unexpected case of Bartonella quintana endocarditis and pauci-immune glomerulonephritis in a patient without known risk factors in Los Angeles, California, USA, highlighting that infection can occur in the general population without a history of homelessness. The diagnosis was challenging and made definitively through extensive diagnostic tests and multidisciplinary investigation.

Brucella suis infection in the United States is typically from feral swine exposure. We describe a case of B. suis cardiac implantable device infection in a man exposed to meat and blood from feral swine in Florida, USA. The infection was diagnosed using culture, molecular diagnostics, and whole-genome sequencing.

The bacterium Treponema pallidum pertenue causes yaws in humans and nonhuman primates. We describe 33% T. pallidum pertenue seropositivity in 9 species of nonhuman primates in Uganda and Rwanda, seroconversion during a lethal outbreak and a novel bacterial genomic lineage. Yaws may threaten both public health and conservation in the region.

Serum samples from wild mammals inhabiting Alaska, USA, showed that 4 species, including Ursus arctos bears and Vulpes vulpes foxes, were exposed to influenza A(H5N1) viruses. Results indicated some mammals in Alaska survived H5N1 virus infection. Surveillance efforts may be improved by incorporating information on susceptibility and detectable immune responses among wild mammals.

In the United States, alpha-gal syndrome (AGS) is primarily associated with lone star tick (Amblyomma americanum) bites. We describe AGS onset after an Ixodes scapularis tick bite and present AGS surveillance in Maine, 2014–2023. US health and public health professionals should be aware of AGS outside the established lone star tick range.

We report the detection of batborne hantaviruses in 2 bat species (Aselliscus stoliczkanus and Hipposideros gentilis) in Laos, expanding the known geographic distribution of hantaviruses in Southeast Asia. Given the frequent human–wildlife contact in the region, researchers should continue to characterize the viruses and investigate their zoonotic potential.

After nearly 4 decades, Brucella abortus has reemerged in Israel, triggering an outbreak across 2 dairy farms (82/137 cows affected), as well as cases in dogs and 1 human case. Despite thorough epidemiologic and genomic investigation, the outbreak source remains unidentified. Such reemergence poses One Health challenges and necessitates ongoing surveillance.

Long-term serologic surveillance of red-legged partridges suggests emergence of Bagaza virus in Portugal in 2021, associated with disease outbreaks in this species. Results also reveal sporadic circulation of Usutu virus and endemic circulation of West Nile virus, highlighting the role of red-legged partridges in the transmission and maintenance cycle and as sentinels of orthoflaviviruses.

We describe a case of alpha-gal syndrome (AGS) in a resident of Washington, USA, after local Ixodes pacificus tick bites, which were associated with IgE increases after diagnosis. AGS should be considered a potential cause of anaphylactic and allergic reactions in persons with tick exposures, regardless of geographic residence.

We measured stability of infectious influenza A(H5N1) virus in irradiated raw milk and wastewater and on surfaces. We found a relatively slow decay in milk, indicating that contaminated milk and fomites pose transmission risks. Although the risk is low, our results call for caution in milk handling and disposal from infected cattle.

During May–December 2024, we detected Oropouche virus (OROV) in 13.9% (263/1,890) of febrile patients in Ceará state, Brazil. Genomic sequencing revealed those cases were caused by a novel OROV reassortant previously identified in the Amazon region. Our data show the introduction and establishment of OROV transmission in Ceará, northeastern Brazil.

Japan experienced substantial increases in streptococcal toxic shock syndrome and group A Streptococcus pharyngitis after relaxing COVID-19 restrictions in May 2023. Increased detection of the M1_UK lineage of Streptococcus pyogenes, especially in the vicinity of Tokyo, emphasizes the need to raise awareness of disease characteristics and epidemiologic trends.

Data on enteric yersinioses in Central America are limited. Genomic characterization of 78 Yersinia enterocolitica isolates from Costa Rica indicated persistent infection-source circulation between animal reservoirs and humans, as well as unusual antimicrobial resistance levels. Our study highlights the importance of genomic surveillance to monitor Yersinia-caused infections in Costa Rica.

Human granulocytic anaplasmosis is a tickborne infection characterized by fever, thrombocytopenia, leukopenia, transaminitis, or a combination of those. Treatment must be prompt and appropriately targeted to prevent clinical decompensation. We discuss an unusual cluster of 16 probable cases in Ontario, Canada, during June–August 2021.

We detected yellow fever virus in Haemagogus mosquitoes collected in 2022 in an Amazon rainforest bordering Manaus, Brazil. The viral genome sequence occupied a basal position within the South American I genotype 1E lineage. Our findings reinforce the Amazon Basin as a source for yellow fever virus re-emergence.

The 2058T macrolide resistance–associated mutation in 23S rRNA has emerged in Mycoplasma genitalium in France. Using mgpB typing, we documented the spread of a macrolide- and moxifloxacin-resistant ST159 clone, harboring the A2058T and ParC Ser83Ile mutations. In France, that clone is likely circulating among men who have sex with men.

We identified 34 patients with Coxiella burnetii infection using PCR; 31 (86%) cases were diagnosed from cardiac specimens. Nearly half (15/31, 48%) of those cases were not reported to any channel of national disease surveillance, indicating substantial underreporting for diseases identified using molecular methods at noncommercial laboratories.

We report Sindbis virus circulation in the Netherlands based on serologic evidence found in 6 resident wild birds and 3 horses (2021–2022). Tested mosquitoes were molecularly negative, and humans were serologically negative. Veterinarians and health practitioners in the Netherlands should be aware of the importance of surveillance for Sindbis virus.

Nipah virus, a zoonotic virus with a high mortality rate, threatens people from Indonesia because of its proximity to affected regions and the presence of bat reservoirs. Molecular screening of 64 Pteropus hypomelanus bats in Central Java detected 2 positive bats. Public health authorities should increase surveillance to help prevent human transmission.

We identified hepatitis E virus (HEV) 3ra, a potentially zoonotic subtype, in rabbits in Ukraine, which highlights their potential role as reservoirs. Screening of rabbit fecal samples identified HEV-3ra. Public health services in this country should improve HEV surveillance and expand HEV sampling.

We report a rare case of pneumonia caused by human mastadenovirus (HAdV) B55 in France in a patient without recent travel history. HAdV-B55 infection was identified retrospectively after being detected in feces during an investigation for concomitant diarrhea. This case suggests possible silent endemic circulation of HAdV-B55 in France.

Since March 2024, highly pathogenic avian influenza A(H5N1) viruses have caused outbreaks in dairy cattle and poultry in the United States, and they continue to spill over into humans. However, data on human immune response to those viruses is limited. We report neutralizing antibody responses in 2 dairy farm worker H5N1 cases.

We describe introduction of the 2022–2023 Oropouche virus lineage from Brazil, which has caused large-scale outbreaks throughout Brazil, into the Amazon Region of Peru. This lineage is co-circulating with another lineage that was circulating previously. Our findings highlight the need for continued surveillance to monitor Oropouche virus in Peru.

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.

Xenotransplantation, transplantation into humans of vascularized organs or viable cells from nonhuman species, is a potential solution to shortages of transplantable human organs. Among challenges to application of clinical xenotransplantation are unknown risks of transmission of animal microbes to immunosuppressed recipients or the community. Experience in allotransplantation and in preclinical models suggests that viral infections are the greatest concern. Worldwide, the distribution of swine pathogens is heterogeneous and cannot be fully controlled by international agricultural regulations. It is possible to screen source animals for potential human pathogens before procuring organs in a manner not possible within the time available for surveillance testing in allotransplantation. Infection control measures require microbiological assays for surveillance of source animals and xenograft recipients and research into zoonotic potential of porcine organisms. Available data suggest that infectious risks of xenotransplantation are manageable and that clinical trials can advance with appropriate protocols for microbiological monitoring of source animals and recipients.

We conducted surveillance for carbapenem-resistant Enterobacterales (CRE) during 2016–2020 at 10 US sites and extended-spectrum β-lactamase–producing Enterobacterales (ESBL-E) during 2019–2020 at 6 US sites. Among 159 CRE cases in children (median age 5 years), CRE was isolated from urine for 131 (82.4%) and blood from 20 (12.6%). Annual CRE incidence rate (cases/100,000 population) was 0.47–0.87. Among 207 ESBL-E cases in children (median age 6 years), ESBL-E was isolated from urine of 196 (94.7%) and blood of 8 (3.9%). Annual ESBL-E incidence rate was 26.5 in 2019 and 19.63 in 2020. CRE and ESBL-E rates were >2-fold higher among infants than other age groups. Most CRE and ESBL-E cases were healthcare-associated community-onset (68 [43.0%] for CRE vs. 40 [23.7%] for ESBL-E) or community-associated (43 [27.2%] for CRE vs. 109 [64.5%] for ESBL-E). Programs to detect, prevent, and treat multidrug-resistant infections must include pediatric populations (particularly the youngest) and outpatient settings.

Crimean-Congo hemorrhagic fever (CCHF) is a tickborne infection that can range from asymptomatic to fatal and has been described in >30 countries. Early identification and isolation of patients with suspected or confirmed CCHF and the use of appropriate prevention and control measures are essential for preventing human-to-human transmission. Here, we provide an overview of the epidemiology, clinical features, and prevention and control of CCHF. CCHF poses a continued public health threat given its wide geographic distribution, potential to spread to new regions, propensity for genetic variability, and potential for severe and fatal illness, in addition to the limited medical countermeasures for prophylaxis and treatment. A high index of suspicion, comprehensive travel and epidemiologic history, and clinical evaluation are essential for prompt diagnosis. Infection control measures can be effective in reducing the risk for transmission but require correct and consistent application.

Crimean-Congo hemorrhagic fever virus (CCHFV) is the most geographically widespread tickborne viral infection worldwide and has a fatality rate of up to 62%. Despite its widespread range and high fatality rate, no vaccines or treatments are currently approved by regulatory agencies in the United States or Europe. Supportive treatment remains the standard of care, but the use of antiviral medications developed for other viral infections have been considered. We reviewed published literature to summarize the main aspects of CCHFV infection in humans. We provide an overview of diagnostic testing and management and medical countermeasures, including investigational vaccines and limited therapeutics. CCHFV continues to pose a public health threat because of its wide geographic distribution, potential to spread to new regions, propensity for genetic variability, potential for severe and fatal illness, and limited medical countermeasures for prophylaxis and treatment. Clinicians should become familiar with available diagnostic and management tools for CCHFV infections in humans.