Search Results (80)

Determining the transmission routes of pathogens in indoor environments is challenging, with most studies limited to specific case analyses and pilot experiments. When pathogens are instantaneously released by a patient in an indoor environment, the peak infection risk may not occur immediately but may instead appear at a specific moment during the pathogen’s spread. We developed a concise model to describe the temporal crest of infection risk. The model incorporates the transmission and degradation characteristics of aerosols and surface particles to predict infection risks via air and surface routes. Only four real-world outbreaks met the criteria for validating this phenomenon. Based on the available data, norovirus is likely to transmit primarily via surface touch (i.e., the fomite route). In contrast, crests of infection risk were not observed in outbreaks of respiratory diseases (e.g., SARS-CoV-2), suggesting a minimal probability of surface transmission in such cases. The new model can serve as a preliminary indicator for identifying different indoor pathogen transmission routes (e.g., food, air, or fomite). Further analyses of pathogens’ transmission routes require additional evidence. Full article

Objectives: Burkholderia cepacia complex (Bcc), a Gram-negative organism, is a well-recognized cause of hospital outbreaks, often linked to a contaminated shared source, such as multidose medications. In this study, we report an outbreak of Bcc infections in a tertiary care hospital, associated with the intrinsic contamination of a prepared solution used in interventional radiology (IR) procedures. Additionally, we provide a detailed explanation of the interventions implemented to control and interrupt the outbreak. Methods: Records from the infection control committee from 1 January 2023 to 31 October 2024 were screened to identify cases with Bcc growth in cultured blood, urine, or respiratory samples. Clinical and laboratory data were collected in March 2025. Bacterial identification was performed using conventional methods and MALDI-TOF (Bruker Daltonics, Bremen, Germany). Controls were matched to cases by ward, date of initial growth, and duration of hospitalization. Demographic and clinical data of these patients were systematically collected and analyzed. Microbiological cultures were obtained from environmental objects of concern and certain medications. Results: A total of 82 Burkholderia species were identified. We enrolled 77 cases and 77 matched controls. The source of contamination was identified in ready-to-use intravenous medications (remifentanil and magnesium preparations) in the IR department. These preparations were compounded in advance by the team and were used repeatedly. Although the outbreak originated from contaminated IV medications used in IR, secondary transmission likely affected 28 non-IR patients via fomites, shared environments, and possible lapses in isolation precautions. The mortality rate among the cases was 16.9%. Infection with Bcc was associated with prolonged intensive care unit stays (p = 0.018) and an extended overall hospitalization duration (p < 0.001); however, it was not associated with increased mortality. The enforcement of contact precautions and comprehensive environmental decontamination successfully reduced the incidence of the Bcc outbreak. No pathogens were detected in cultures obtained after the disinfection. Conclusions: The hospital transmission of Bcc is likely driven by cross-contamination, invasive medical procedures, and the administration of contaminated medications. Implementing stringent infection control measures such as staff retraining, updated policies on medication use, enhanced environmental decontamination, and strict adherence to isolation precautions has proven effective in curbing the spread of virulent and transmissible Bcc. Full article

Enteroviruses of the Picornaviridae family are transmitted primarily by the fecal–oral route. Transmission may occur following hand contact with contaminated fomites and subsequent ingestion of virus conveyed to the mouth by the contaminated hand. The persistence of these viruses on fomites likely plays a role in this transmission scenario. Six echoviruses (1, 2, 3, 5, 6, and 7) that cause frequently reported clinical cases in the United States were studied, along with poliovirus type 1 vaccine strain LSc-2ab. The infectivity half-lives of the enteroviruses deposited on vinyl tile coupons in a 10% fecal solution ranged from 1.7 to 12.6 h. The echovirus serotypes most commonly associated with reported infections persisted longer on the vinyl tiles than the less commonly reported types. This increased persistence on surfaces may favor the transmission of these echoviruses through the fecal–oral route. These results inform the future selection of appropriate model enteroviruses for challenging newly formulated and eco-friendly disinfectants or other strategies in infection prevention and control for enteroviruses. Full article

The transmission of infectious diseases via the use of public restrooms has been previously documented. The goal of this study was to compare bacterial contamination in public vs. household restrooms and, using quantitative microbial risk assessment (QMRA), to assess the probability of infection from fomite contact with selected high-touch sites within the restrooms. Fomite surfaces in four public and four household restrooms were sampled over a period of two months. The public restrooms were in an office building occupied by 80 individuals and were considered moderate usage. The toilet seat, toilet flush handle, countertops, and floor were sampled for heterotrophic, coliform, and Escherichia coli bacteria. The highest numbers of heterotrophic bacteria and coliforms were detected on the countertops, followed by the floor. The greatest numbers of E. coli were recovered from the countertops in the household restroom, but the greatest numbers in the public restroom were recovered from the toilet flush handle. Numbers of heterotrophic bacteria and coliforms were 10 to 100 times greater in household restrooms than in public restrooms. The QMRA suggested that the greatest risk of acquiring a norovirus infection involved the touching of the countertops in household restrooms and the toilet flush handles in public restrooms. Full article

Trichomonas tenax is an anaerobic flagellate usually found in the oral cavity of humans and domestic animals. It is very likely to be transmitted through kissing, sharing saliva, contaminated utensils, and water. However, research on its transmission dynamics is scarce. Hence, there is a need to identify potential knowledge gaps in T. tenax transmission for future research and emphasize the importance of the One Health approach in controlling the spread of this flagellar protozoan. Trichomonas tenax has been found in humans, dogs, cats, horses, and birds at various body sites, including the lungs and the urogenital tract, in addition to the oral cavity. Its transmission is influenced by environmental factors such as temperature and socioeconomic factors such as age, income, smoking, and public awareness, along with poor oral hygiene and systemic diseases. Direct host-to-host transmission also plays an important role; however, transmission through fomites or contaminated water still needs to be scientifically proven to gain a better understanding of these mechanisms. More studies on this flagellate are warranted, especially using animal models and epidemiological studies, to better understand its transmission dynamics. Prioritizing research in these areas could result in a more comprehensive understanding of T. tenax transmission dynamics and the factors that influence it, ultimately aiding in the development of effective control and prevention strategies. It is also recommended to encourage collaboration between medical and veterinary professionals in addressing this zoonotic protozoan, recognizing that it aligns with the One Health approach. Full article

Autochthonous Chagas disease remains a health risk for humans in Latin American countries but is rarely found among residents of the United States (US), despite the presence of competent insect vectors and small mammal reservoirs of Trypanosoma cruzi in the lower two-thirds of the US. This report discusses the differences in the rates of autochthonous Chagas disease in Latin America and the US. The key to the differences may lie in the mode (or means) of transmission of parasites to humans. In both Latin America and the US, the so-called vectorial transmission of Chagas disease to humans is the mode of acquisition accepted by most authorities. This mode involves the improbable combination of an infected kissing bug defecating near the mouth or eyes or the site of the bite, followed by the bite victim rubbing infected feces into the wound site or mucous membranes. Outbreaks of Chagas disease due to fecal–oral contamination, known as oral Chagas, have been recorded in Latin America for decades, and at present, oral Chagas is the predominant mode of infection recognized in Brazil. It is perhaps time to consider fecal–oral transmission in its many manifestations as a risk factor for Chagas disease in the US rather than reflexively invoking vectorial transmission. Fecal–oral transmission includes contamination of food and drink by triatomine feces and infection via contaminated fomites and surfaces at home and at worksites, as well as transmission from infected small mammals and other routes discussed in this report. Full article

Restrooms are associated with the transmission of bacterial and viral illnesses. Disinfecting contaminated surfaces is associated with reducing transmission risk. The goal of this study was to determine how cleaning/disinfecting frequency affects restroom pathogen contamination. The Phase 1 intervention included cleaning toilet surfaces (the toilet bowl, water, and rim) using 9.5% w/w hydrochloric acid. The Phase 2 intervention used fomite-specific products to clean/disinfect additional restroom surfaces, including the vanity countertop, sink faucet handle, toilet seat, flush handle, floor, and doorknob. A designated household member was responsible for cleaning/disinfecting surfaces at the beginning of each interval. Fomite sample collection was randomized, and samples were tested for heterotrophic, coliform, and Escherichia coli bacteria after specified intervals: 1, 2, 3, or 7 days. The greatest numbers of bacteria and largest reductions occurred on fomites after three days. A statistically significant difference was found for heterotrophic bacteria (p = 0.009), coliforms (p = 0.10), and E. coli (p = 0.13) with cleaning/disinfecting every three days. A quantitative microbial risk assessment (QMRA) estimated a >98% reduction in risk of infection by norovirus with an every-3-day cleaning/disinfection routine on the most heavily contaminated sites. Results indicate an optimal cleaning frequency of twice weekly for minimizing exposure to pathogens. Full article

In 2011–2013, we isolated and characterized small ruminant lentiviruses (SRLVs) from two flocks, one of goats and the other of sheep, that had never been in direct contact. Phylogenetic analysis of these viruses indicated a common origin, which led us to hypothesize indirect transmission of these viruses between the two flocks. Since, to our knowledge, there are no published data on the tenacity of these viruses, we started this work. In the first part, we monitored the loss of infectivity of two prototypic SRLV strains, MVV 1514 and CAEV-CO, over time, in liquid suspension. As expected, the suspensions stored at 4 °C better preserved the infectivity of the viruses. Additionally, viruses resuspended in milk, the medium mirroring the in vivo situation, proved more tenacious than those maintained in a cell culture medium. These viruses, subjected to harsh treatments such as drying and resuspending, partially maintained their replication capacity. After an immediate loss of nearly 1 log₁₀ TCID₅₀ immediately after desiccation, the viruses maintained their replication capacity for at least three weeks when desiccated in milk. These results suggest that fomites, clothing, or pastures contaminated with secretions or milk from infected animals might mediate the infection of animals independently of direct contact. Full article

The increasing need for effective antiviral strategies has led to the development of innovative surface coatings to combat the transmission of viruses via fomites. The aim of this review is to critically assess the efficacy of antiviral coatings in mitigating virus transmission, particularly those activated by visible light. The alarm created by the COVID-19 pandemic, including the initial uncertainty about the mechanisms of its spread, attracted attention to fomites as a possible source of virus transmission. However, later research has shown that surface-dependent infection mechanisms need to be carefully evaluated experimentally. By briefly analyzing virus–surface interactions and their implications, this review highlights the importance of shifting to innovative solutions. In particular, visible-light-activated antiviral coatings that use reactive oxygen species such as singlet oxygen to disrupt viral components have emerged as promising options. These coatings can allow for obtaining safe, continuous, and long-term active biocidal surfaces suitable for various applications, including healthcare environments and public spaces. This review indicates that while the significance of fomite transmission is context-dependent, advances in material science provide actionable pathways for designing multifunctional, visible-light-activated antiviral coatings. These innovations align with the lessons learned from the COVID-19 pandemic and pave the way for sustainable, broad-spectrum antiviral solutions capable of addressing future public health challenges. Full article

Resuspended particles from human activities can contribute to pathogen exposure via airborne fomite contamination in built environments. Studies investigating the dissemination of resuspended viruses are limited. The goal of this study was to explore viral dissemination after aerosolized resuspension via human activities on indoor flooring. Nylon carpet or wood flooring was seeded with virus (MS2) or virus laden dust then evaluated after activities, i.e., walking and vacuuming. Statistically significant differences were found in dispersal of virus laden dust after vacuuming carpet (p-value = 5.8 × 10⁻⁶) and wood (p-value = 0.003, distance > 12 in/30 cm). Significant differences were also found between floor materials and virus laden dust dispersal vacuuming (p = 2.09 × 10⁻⁵) and walking (p = 2.68 × 10⁻²). A quantitative microbial risk assessment (QMRA) scenario using Norovirus and a single fomite touch followed by a single hand-to-mouth touch indicated a statistically significant difference associated with virus laden dust particles and vacuuming carpet(p < 0.001). Infection risks were 1 to 5 log₁₀ greater for dust exposure. The greatest risk reductions from fomites were seen across vacuuming carpet no-dust scenarios for surfaces <30 cm from flooring. More research is needed to determine the role resuspension plays in exposure and transmission of potentially infectious agents. Full article

Meticillin-resistant Staphylococcus aureus (MRSA) is a significant cause of hospital-acquired infections (HAIs), posing a serious threat to healthcare workers (HCWs). All touching behavior data were from a clinical skills competition of a medical school in Hong Kong; more than 12,000 touches involving 3 patients (infusion, critically ill, and agitation) and 25 HCWs were collected. A fomite transmission model considering real touch behaviors was established to simulate the MRSA transmission in an emergency room, then the MRSA exposure risk of HCWs and effectiveness of interventions were analyzed. HCWs had a low touch frequency of facial mucous (doctors: 1.7 times/h; nurses: 1.1 times/h). The MRSA intake fractions for doctors were 2–4 times higher than those for nurses. Handwashing twice per hour could reduce the MRSA intake fraction by 7%. Effectiveness of disinfecting only the top 10 high-risk public surfaces was 83% to 98% of the efficiency when disinfecting all public surfaces. MRSA mainly transferred via hand contact contributed over 89% of pathogen transmission. Therefore, disinfecting public surfaces or replacing them with antimicrobial surfaces was not effective. The findings highlight the importance of prioritizing hand hygiene among HCWs and optimizing interventions to enhance infection-control protocols in emergency rooms. And this study provides scientific evidence for the development of precise interventions for MRSA prevention and control in hospital emergency rooms. Full article

In light of the close contact between patient and clinician during ophthalmic examinations and the multiple opportunities for pathogen transmission, we identified and evaluated potential pathogen transmission routes through high-touch surfaces in an outpatient ophthalmology clinic. A circuit simulation was performed to replicate a patient’s journey through an ophthalmology clinic with various stations. Fluorescent oil and powder were applied to the hands of Simulated Patient A who went through the circuit. Routine disinfection of surfaces in the slit lamp environment and hand hygiene by the ophthalmologist were conducted prior to Simulated Patient B going through the same circuit with untagged hands. Ultraviolet black light was used to identify fluorescent marker contamination after Simulated Patient B completed the circuit. Fluorescent marker contamination was found on the hands of all the simulated patients and staff, various items of the simulated patients, multiple equipment surfaces—particularly the ophthalmologist’s working table and slit lamp environment—and miscellaneous objects like appointment cards and files. Fluorescent marker contamination on Simulated Patient B’s untagged hands despite proper hand hygiene being performed prior suggests suboptimal surface disinfection following Simulated Patient A’s circuit. Through this pilot study, we recognised the key role that ophthalmic high-touch surfaces play in fomite transmission and that thorough disinfection of high-touch surfaces is essential on top of proper hand hygiene. With the contact sequences delineated in this pilot study, specific cues for hand hygiene and surface disinfection may be implemented at suitable intervals during contact with high-touch surfaces. Environmental decontamination adjuncts could also be considered to reinforce surface disinfection. Full article

Coronaviruses (CoVs), a subfamily of Orthocoronavirinae, are viruses that sometimes present a zoonotic character. Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is responsible for the recent outbreak of COVID-19, which, since its outbreak in 2019, has caused about 774,593,066 confirmed cases and 7,028,881 deaths. Aereosols are the main route of transmission among people; however, viral droplets can contaminate surfaces and fomites as well as particulate matter (PM) in suspensions of natural and human origin. Honey bees are well known bioindicators of the presence of pollutants and PMs in the environment as they can collect a great variety of substances during their foraging activities. The aim of this study was to evaluate the possible role of honey bees as bioindicators of the prevalence SARS-CoV-2. In this regard, 91 samples of honey bees and 6 of honey were collected from different apiaries of Campania region (Southern Italy) in four time periods from September 2020 to June 2022 and were analyzed with Droplet Digital RT-PCR for SARS-CoV-2 target genes Orf1b and N. The screening revealed the presence of SARS-CoV-2 in 12/91 in honey bee samples and in 2/6 honey samples. These results suggest that honey bees could also be used as indicators of outbreaks of airborne pathogens such as SARS-CoV-2. Full article

Antimicrobial resistance (AMR) poses several issues concerning the management of hospital-acquired infections, leading to increasing morbidity and mortality rates and higher costs of care. Multidrug-resistant (MDR) bacteria can spread in the healthcare setting by different ways. The most important are direct contact transmission occurring when an individual comes into physical contact with an infected or colonized patient (which can involve healthcare workers, patients, or visitors) and indirect contact transmission occurring when a person touches contaminated objects or surfaces in the hospital environment. Furthermore, in recent years, toilets in hospital settings have been increasingly recognised as a hidden source of MDR bacteria. Different sites in restrooms, from toilets and hoppers to drains and siphons, can become contaminated with MDR bacteria that can persist there for long time periods. Therefore, shared toilets may play an important role in the transmission of nosocomial infections since they could represent a reservoir for MDR bacteria. Such pathogens can be further disseminated by bioaerosol and/or droplets potentially produced during toilet use or flushing and be transmitted by inhalation and contact with contaminated fomites. In this review, we summarize available evidence regarding the molecular features of MDR bacteria contaminating toilets of healthcare environments, with a particular focus on plumbing components and sanitary installation. The presence of bacteria with specific molecular traits in different toilet sites should be considered when adopting effective managing and containing interventions against nosocomial infections potentially due to environmental contamination. Finally, here we provide an overview of traditional and new approaches to reduce the spreading of such infections. Full article

Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically important diseases of swine, with losses due to poor reproductive performance and high piglet and growing pig mortality. Transmission of porcine reproductive and respiratory syndrome virus (PRRSV) may occur by both direct and indirect routes; the latter includes exposure to PRRSV-contaminated fomites, aerosols, and arthropod vectors. This review has collected available data on the ex-vivo environmental stability and persistence of PRRSV in an effort to highlight important sources of the virus and to determine the role of environmental conditions on the stability of the virus, especially temperature. The ex-vivo settings include fomites (solid, porous, and liquid fomites), insects, people, and pork meat, as well as the role of environmental conditions on the stability of the virus, especially temperature. Full article