Divergent water requirements partition exposure risk to parasites in wild equids.

For grazing herbivores, dung density in feeding areas is an important determinant of exposure risk to fecal-orally transmitted parasites. When host species share the same parasite species, a nonrandom distribution of their cumulative dung density and/or nonrandom ranging and feeding behavior may skew exposure risk and the relative selection pressure parasites impose on each host. The arid-adapted Grevy's zebra (Equus grevyi) can range more widely than the water-dependent plains zebra (Equus quagga), with which it shares the same species of gastrointestinal nematodes. We studied how the spatial distribution of zebra dung relates to ranging and feeding behavior to assess parasite exposure risk in Grevy's and plains zebras at a site inhabited by both zebra species. We found that zebra dung density declined with distance from water, Grevy's zebra home ranges (excluding those of territorial males) were farther from water than those of plains zebras, and plains zebra grazing areas had higher dung density than random points while Grevy's zebra grazing areas did not, suggesting a greater exposure risk in plains zebras associated with their water dependence. Fecal egg counts increased with home range proximity to water for both species, but the response was stronger in plains zebras, indicating that this host species may be particularly vulnerable to the elevated exposure risk close to water. We further ran experiments on microclimatic effects on dung infectivity and showed that fewer nematode eggs embryonated in dung in the sun than in the shade. However, only 5% of the zebra dung on the landscape was in shade, indicating that the microclimatic effects of shade on the density of infective larvae is not a major influence on exposure risk dynamics. Ranging constraints based on water requirements appear to be key mediators of nematode parasite exposure in free-ranging equids.

Correction to: Scaling Safe Access to Fecal Microbiota Transplantation: Past, Present, and Future.

In the original version of this article, author Ryan Elliott's name was misspelled as Ryan Eliott. The correct spelling of the name is Ryan Elliott.

Scaling Safe Access to Fecal Microbiota Transplantation: Past, Present, and Future.

PURPOSE OF REVIEW: Universal stool banks (USBs) have emerged as a potential model for scaling access to fecal microbiota transplantation (FMT) for Clostridium difficile infection (CDI). In this review, we outline the historical barriers constraining access to FMT, the evidence on methods and outcomes of USBs, and potential future directions for expanding access. RECENT FINDINGS: Key historical barriers to FMT access include regulatory uncertainty, operational complexity of sourcing screened donor material, and logistical challenges of delivering fresh treatment preparations. USBs have demonstrated that FMT can be delivered safely at scale by centralizing donor selection, material processing, and safety monitoring. More evidence is needed to optimize USB methods, including for donor screening, material processing, and novel delivery modalities. USBs have catalyzed broad access to FMT in North America and Europe. Future directions include developing evidence regarding oral preparations, harmonizing guidelines, disseminating best practice protocols, establishing long-term safety profiles, and expanding access to geographic areas of unmet need.