Biology subjects

Schmid, B. V.

Publications and source records attributed to Schmid, B. V..

4 recordsLinked to original sources

bioRxiv2026

From Movement to Spread: Generating Livestock Contact Networks that Preserve Infection Dynamics

Animal trade links livestock holdings through contacts that change from day to day, making movement networks vital for epidemic analysis and control. Official movement records reveal these transmission routes, but privacy concerns often restrict access to the original data. Furthermore, epidemiological studies frequently require synthetic networks that accurately preserve the structural and temporal dynamics driving disease spread. Here we introduce NetForge, a mechanism-informed generative framework that learns recurring sender--receiver roles from movement and farm information of Dutch national pig-movement records. We compared generators with varying structural and temporal constraints. Among them, the Operational Stochastic Block Model regime performed best by combining learned trade partner structure with constraints on how contacts persist, return, or first appear. It closely matched the accumulation of potential spreading routes in the observed network and reproduced its simulated disease transmission trajectories. Together, we show that pairing trade structure with temporal constraints is essential for capturing infection dynamics. Because NetForge models trade data as a sequence of time-framed networks, it aligns well with routinely collected movement records and provides practical guidance for building more realistic synthetic movement networks from empirical trade records.

ecology↗

bioRxiv2021

Plague risk in the western United States over seven decades of environmental change

After several pandemics over the last two millennia, the wildlife reservoirs of plague (Yersinia pestis) now persist around the world, including in the western United States. Routine surveillance in this region has generated comprehensive records of human cases and animal seroprevalence, creating a unique opportunity to test how plague reservoirs are responding to environmental change. Here, we develop a new method to detect the signal of climate change in infectious disease distributions, and test whether plague reservoirs and spillover risk have shifted since 1950. We find that plague foci are associated with high-elevation rodent communities, and soil biochemistry may play a key role in the geography of long-term persistence. In addition, we find that human cases are concentrated only in a small subset of endemic areas, and that spillover events are driven by higher rodent species richness (the amplification hypothesis) and climatic anomalies (the trophic cascade hypothesis). Using our detection model, we find that due to the changing climate, rodent communities at high elevations have become more conducive to the establishment of plague reservoirs--with suitability increasing up to 40% in some places--and that spillover risk to humans at mid-elevations has increased as well, although more gradually. These results highlight opportunities for deeper investigation of plague ecology, the value of integrative surveillance for infectious disease geography, and the need for further research into ongoing climate change impacts.

ecology↗

bioRxiv2018

The genome of the plague-resistant great gerbil reveals species-specific duplication of an MHCII gene

The great gerbil (Rhombomys opimus) is a social rodent living in permanent, complex burrow systems distributed throughout Central Asia, where it serves as the main host of several important vector-borne infectious diseases and is defined as a key reservoir species for plague (Yersinia pestis). Studies from the wild have shown that the great gerbil is largely resistant to plague but the genetic basis for resistance is yet to be determined. Here, we present a highly contiguous annotated genome assembly of great gerbil, covering over 96 % of the estimated 2.47 Gb genome. Comparative genomic analyses focusing on the immune gene repertoire, reveal shared gene losses within TLR gene families (i.e. TLR8, TLR10 and all members of TLR11-subfamily) for the Gerbillinae lineage, accompanied with signs of diversifying selection of TLR7 and TLR9. Most notably, we find a great gerbil-specific duplication of the MHCII DRB locus. In silico analyses suggest that the duplicated gene provides high peptide binding affinity for Yersiniae epitopes. The great gerbil genome provides new insights into the genomic landscape that confers immunological resistance towards plague. The high affinity for Yersinia epitopes could be key in our understanding of the high resistance in great gerbils, putatively conferring a faster initiation of the adaptive immune response leading to survival of the infection. Our study demonstrates the power of studying zoonosis in natural hosts through the generation of a genome resource for further comparative and experimental work on plague survival and evolution of host-pathogen interactions.

genomics↗

bioRxiv2018

Epidemiology of a bubonic plague outbreak in Glasgow, Scotland in 1900

On August 3, 1900, bubonic plague (Yersinia pestis) broke out in Glasgow for the first time during the Third Pandemic. The local sanitary authorities rigorously tracked the spread of the disease and they found that nearly all of the 35 cases could be linked by contact with a previous case. Despite trapping hundreds of rats in the area, there was no evidence of a rat epizootic and the investigators speculated that the outbreak could be due to human-to-human transmission of bubonic plague. Here we use a likelihood-based method to reconstruct transmission trees for the outbreak. From the description of the outbreak and the reconstructed trees, we infer several epidemiological parameters. We found that the estimated mean serial interval was 7.4 days and the mean effective reproduction number dropped below 1 after implementation of control measures. We also found that there was a high rate of secondary transmissions within households and observations of transmissions from individuals who were not terminally septicemic. Our results provide important insights into the epidemiology of plague that are useful for modeling current and historic plague epidemics.

epidemiology↗