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The joint influence of abiotic and biotic factors is important for understanding the transmission of generalist pathogens. Abiotic factors such as temperature can directly influence pathogen persistence in the environment and will also affect biotic factors, such as host community composition and abundance. At intermediate spatial scales, the effects of temperature, community composition, and host abundance are expected to contribute to generalist pathogen transmission. We use a simple transmission model to explain and predict how host community composition, host abundance, and environmental pathogen persistence times can independently and jointly influence transmission. Our transmission model clarifies how abiotic and biotic factors can synergistically support the transmission of a pathogen. The empirical data show that high community competence, high abundance, and low temperatures correlate with high levels of transmission of ranavirus in larval amphibian communities. Discrete wetlands inhabited by larval amphibians in the presence of ranavirus provide a compelling case study comprising distinct host communities at a spatial scale anticipated to demonstrate abiotic and biotic influence on transmission. We use these host communities to observe phenomena demonstrated in our theoretical model. These findings emphasize the importance of considering both abiotic and biotic factors, and concomitant direct and indirect mechanisms, in the study of pathogen transmission and should extend to other generalist pathogens with the capacity for environmental transmission. Host community composition and abundance and environmental conditions such as ambient temperature all influence disease transmission but are often considered independently. We use a theoretical model to study the joint effects of these factors on the transmission of a generalist pathogen with capacity for contact and environmental transmission, and then we compare these results to empirical observations of ranavirus transmission in larval amphibian communities to show that these factors jointly influence transmission.

Parasites can play key roles in ecosystems, especially when they infect common hosts that play important ecological roles. Daphnia are critical grazers in many lentic freshwater ecosystems and typically reach peak densities in early spring. Daphnia have also become prominent model host organisms for the field of disease ecology, although most well-studied parasites infect them in summer or fall. Here, we report field patterns of virulent microsporidian parasites that consistently infect Daphnia in springtime, in a set of seven shallow ponds in Georgia, USA, sampled every 3–4 weeks for 18 months. We detected two distinct parasite taxa, closely matching sequences of Pseudoberwaldia daphniae and Conglomerata obtusa, both infecting all three resident species of Daphnia: D. ambigua, D. laevis, and D. parvula. To our knowledge, neither parasite has been previously reported in any of these host species or anywhere in North America. Infection prevalence peaked consistently in February–May, but the severity of these outbreaks differed substantially among ponds. Moreover, host species differed markedly in terms of their maximum infection prevalence (5% [D. parvula] to 72% [D. laevis]), mean reduction of fecundity when infected (70.6% [D. ambigua] to 99.8% [D. laevis]), mean spore yield (62,000 [D. parvula] to 377,000 [D. laevis] per host), and likelihood of being infected by each parasite. The timing and severity of the outbreaks suggests that these parasites could be impactful members of these shallow freshwater ecosystems, and that the strength of their effects is likely to hinge on the composition of ponds’ zooplankton communities.

Ultraviolet-C (UV-C) radiation has emerged as a widely adopted disinfection technology in healthcare settings due to its germicidal effectiveness. However, concerns have grown regarding the potential degradation of materials, particularly polymeric surfaces, subjected to repeated UV-C exposure. Understanding the extent, mechanism, and contributing factors of UV-C-induced material degradation is essential for safe and sustainable implementation. We conducted a scoping literature review in accordance with PRISMA guidelines to evaluate evidence on UV-C-related material degradation. Multiple databases were searched for studies published between January 1, 2000, and August 30, 2024, investigating material degradation under UV-C radiation (100-280 nm) in potentially healthcare-relevant conditions. Data abstraction captured study design, UV-C exposure characteristics, material types, degradation types, and assessment methods. Of the 56 studies reviewed, 14 met inclusion criteria. All employed experimental designs conducted in laboratory settings. UV-C exposure resulted in both visible and structural degradation of several polymeric materials. Polycarbonate, HDPE, and PLA were the most affected, exhibiting yellowing, surface cracking, and loss of mechanical strength. Degradation was time-, dose-, and distance-dependent, with longer exposure, higher irradiance, and shorter distance correlating with more severe damage. Detection methods included visual inspection, microscopy, spectroscopy, and nanoindentation. Some studies reported UV stabilizers and antioxidant additives as potential mitigation strategies. UV-C radiation can cause significant degradation of commonly used polymeric materials. These findings underscore the need for careful selection of materials in UV-C environments and support further research on mitigation strategies to enhance material longevity.

Complement-derived anaphylatoxins regulate immune and inflammatory responses through G-protein-coupled receptor (GPCR)-mediated signalling 1 , 2 , 3 , 4 . C5L2 (also known as GPR77) is a relatively new GPCR thought to be a non-signalling receptor binding to C5a, on the basis of sequence information and experimental evidence 5 , 6 , 7 . Here we show, using gene targeting, that C5L2 is required to facilitate C5a signalling in neutrophils, macrophages and fibroblasts in vitro . Deficiency of C5L2 results in reduced inflammatory cell infiltration, suggesting that C5L2 is critical for optimal C5a-mediated cell infiltration in certain in vivo settings. C5L2 is also involved in optimizing C3a-induced signals. Furthermore, like mice incapable of C3a/complement 3a receptor (C3aR) signalling 4 , 8 , 9 , C5L2-deficient mice are hypersensitive to lipopolysaccharide (LPS)-induced septic shock, show reduced ovalbumin (OVA)-induced airway hyper-responsiveness and inflammation, and are mildly delayed in haematopoietic cell regeneration after γ-irradiation. Our data indicate that C5L2 can function as a positive modulator for both C5a- and C3a-anaphylatoxin-induced responses.

Suppressive antibiotic therapy (SAT) is used to prevent recurrent prosthetic joint infections (PJI) among patients who undergo debridement, antibiotics, and implant retention (DAIR). We aimed to assess SAT outcomes among younger, immunocompetent patients. Retrospective cohort study. Immunocompetent patients <65 years of age who received DAIR for PJI of the hip, knee, or shoulder. Veterans Affairs hospitals. SAT was divided into short-term (oral antibiotics given for <3 months after guideline concordant therapy) and long-term SAT (>3 months to 5 years of oral antibiotics). The primary outcome was treatment failure (TF) and mortality combined. SAT was a time-dependent covariate in Cox proportional hazards models. Of the 938 patients, 15% received short-term SAT, 20% received long-term SAT, and 65% did not receive SAT. Short- and long-term SAT were significantly associated with decreased hazards of TF or mortality (short-term SAT adjusted hazard ratio (aHR) = 0.27; 95% confidence interval (CI): 0.11, 0.67; Long-term SAT aHR = 0.52; 95% CI: 0.30, 0.89). Short-term SAT was significantly associated with infection (aHR: 3.47; 95% CI: 1.38, 8.74). Short-term SAT (aHR: 7.83; 95% CI: 4.80, 12.77) and long-term SAT (aHR: 1.68; 95% CI: 1.19, 2.38) were significantly associated with antibiotic-associated diarrhea. Long-term SAT was not significantly associated with TF alone (aHR = 0.61; 95% CI: 0.32, 1.16). SAT was significantly associated with decreased death or TF and increased side effects. Benefits and risks must be weighed before prescribing SAT to younger, immunocompetent patients.

The Department of Veterans Affairs (VA) does not have system-wide standardized policies or procedures for ultraviolet-C (UV-C) use. Qualitative researchers performed content analysis of VAV UV-C guidance documents. We observed that lack of specificity and uniformity across guidance documents is a potential barrier to UV-C implementation and future quality control.

In this controlled study, we found that exposure to ultraviolet-C (UV-C) radiation was able to arrest the growth of selected pathogenic enteric and nonfermenting Gram-negative rods. Further studies are needed to confirm the clinical efficacy and determine optimal implementation strategies for utilizing UV-C terminal disinfection.

We evaluated barriers and facilitators to patient adherence with a bundled intervention including chlorhexidine gluconate (CHG) bathing and decolonizing Staphylococcus aureus nasal carriers in a real-world setting. Survey data identified 85.5% adherence with home use of CHG as directed and 52.9% adherence with home use of mupirocin as directed.