Research Focus: From tick-borne fever in lambs to maternal RSV vaccine updates

October 2026: A collection of publication highlights from Edinburgh Infectious Diseases over the last month.

Moredun lambs
Photos: Left of Jade Duncan from the Moredun Institute (lead author on the Tick-borne fever paper) and right of the lambs involved in the study.

Subclinical infection with Anaplasma phagocytophilum and gastrointestinal nematodes results in reduced weight gain in grazing weaned lambs

Tick-borne fever (TBF) is caused by the bacterium Anaplasma phagocytophilum (AP), which is spread by ticks. Researchers from the Moredun Institute investigated the effects of AP on lamb productivity and welfare in a UK farm setting through a naturally occurring infection. In 2022, TBF was incidentally diagnosed in lambs undergoing a field study looking at gastrointestinal worms. Of 101 lambs tested, 16 were infected with AP, although most were subclinical. Over 21 weeks, sub-clinically infected lambs gained on average 2.5 kg less than uninfected lambs. 

Higher worm egg counts were also associated with lower weight in AP-infected lambs but not in AP-uninfected lambs. These findings suggest that AP infection may reduce lamb growth even when animals appear healthy. Further research is needed to understand its long-term effects on lamb welfare under UK-specific farm management systems. 

Citation: Duncan JM, Rocchi MS, Stephen A, Hayward AD, Maley M, McDougall H, Brown S, Andrews L, Mitchell G, Kenyon F. Vet J. 2026 Oct;319:106827. doi: 10.1016/j.tvjl.2026.106827. Epub 2026 Aug 13. PMID: 42595214.

Fragmented social networks promote complex behavioural contagions over infectious disease spread

Researchers from the School of Biological Sciences investigated how the structure of animal social networks affects the spread of behaviours and infectious diseases.
 
Using simulations based on real animal social structures, they found that modular networks fragmented into many subgroups can favour the spread of complex behaviours while limiting infectious disease transmission. These findings highlight how the same social structures can have contrasting effects on how information or behaviours, and infectious disease spread.
 
Citation: Nitara Wijayatilake, Shweta Bansal, Amy B Pederson, Matthew Silk, bioRxiv 2025.08.28.672836; doi: https://doi.org/10.1101/2025.08.28.672836

Sequential multimodal imaging of varicella-zoster virus-associated acute retinal necrosis: Insights supporting a neurotropic hypothesis

Researchers from the Royal Infirmary of Edinburgh have been looking to describe how, over tine, the central part of the retina changes in patients with a severe viral eye infection. They then compared what they saw in the patients with an animal model that shows how herpes viruses spread to the retina along nerves.

This was a single-patient study with 30 year old woman with Varicella-Zoster Virus (the virus that causes chickenpox and shingles). The infection had destroyed the outer edge of the retina.. Scans of the central retina showed folds and unusual bright vertical streaks within the layer containing the light-sensing cells. Despite antiviral treatment, she lost almost all vision in that eye, and the eye eventually shrank and stopped functioning.

Repeated scans of the central retina in this patient with a shingles-virus eye infection showed wrinkling of the inner retina and bright vertical streaks in the photoreceptor layer. These appeared before fluid collected under the retina. Researchers suggest this may show the virus travelling along nerve cells from the inner retina to the outer retina, as seen in animal experiments. 

Recognising these scan features could help doctors detect when the infection is reaching the central retina, and help researchers understand how the disease develops in humans.

Citation: Steptoe PJ, Ramalingam S, Dhillon B. Eur J Ophthalmol. 2026 Mar;36(2):NP5-NP11. doi: 10.1177/11206721251388239. Epub 2025 Nov 4. PMID: 41185897; PMCID: PMC12929645.

A generalized lineage nomenclature for viral genomic epidemiology

Pathogen genomics has become increasingly integrated into outbreak response, with recent virus epidemics better characterized by large numbers of viral genetic sequences, however current systems may not accommodate rapid sequence generation.

The Pango lineage nomenclature system was designed to address these problems and has been applied to SARS-CoV-2 since early 2020.

Researchers from the School of Biological Sciences generalize the underlying principles into a framework for virus surveillance. Six years on from the inception of the Pango system, researchers discuss challenges and considerations for implementation. They present a Pango lineage framework for chikungunya virus, providing an alternative to the geography-based clade system and designating 21 lineages across 8 founding lineages.

This generalization provides a foundation for future genomic surveillance of many viruses, including for emerging outbreaks and the surveillance of endemic pathogens.

Citation: Colquhoun R, Hinrichs AS, Hill V, Ruis C, Roemer C, Pybus OG, Rambaut A, O'Toole Á. Nat Microbiol. 2026 Oct;11(10):2901-2910. doi: 10.1038/s41564-026-02468-3. Epub 2026 Sep 30. PMID: 42816583; PMCID: PMC13716827.

E. coli O157:H7 evades CD8+ T cell immunity through T3SS-dependent suppression and limited MHCI presentation of translocated proteins

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes severe disease in humans, but lives in cattle asymptomatically. Cattle are the main source of human infections. To attach to the gut, the bacteria inject proteins into the cells lining the gut. Normally, infected cells display fragments of foreign proteins on their surface so that "killer" T cells can spot and respond to them.

In this study, researchers from the Roslin Institute and Royal (Dick) School of Veterinary Studies infected cow gut cells in the lab and found that very few fragments from the injected bacterial proteins were displayed, which confirmed that the bacteria hide from this immune check. 

Unexpectedly, they identified fragments from intimin, a protein the bacteria use to latch on, that could be recognised by both killer and "helper" T cells. This makes intimin a promising vaccine target. The findings suggest that future cattle vaccines should aim to activate both types of T cell, which could help cows clear the infection and reduce the risk of the bacteria spreading to people.

Citation: Hassan A, Nicastri A, Vasoya D, Alves J, Nielsen M, Gally DL, Ternette N, Corbishley A, Connelley TK. Discov Immunol. 2026 Sep 9;5(1):kyag017. doi: 10.1093/discim/kyag017. PMID: 42846745; PMCID: PMC13643489.

Primordial germ cell-derived macrophages as a platform to study host-pathogen interactions

Chickens play a crucial role in global food security but are susceptible to lots of avian and zoonotic pathogens. Understanding the contribution of pathogen and host factors during infection is important for the design of strategies to control avian diseases, but it is hampered by the lack of reliable and varied avian cell lines for in vitro studies. 

Macrophages are key components of the innate immune system. They serve as a first line of defense against many infectious agents and help to orchestrate adaptive immune responses.

Researchers from the Roslin Institute and Royal (Dick) School of Veterinary Studies established a protocol where chicken primordial germ cells are differentiated into macrophage-like cells, which provide a continuous in vitro supply of functionally active macrophages.

Researchers found that Chicken primordial germ cell-derived macrophages had similar molecular, transcriptional, and functional characteristics to chicken bone-marrow-derived macrophages

Citation: Panda SK, Dehdilani N, Tellez G, Torres RC, Taylor L, Cody C, Halabi S, Wu Z, Hawken R, Stevens MP, McGrew MJ. Front Cell Dev Biol. 2026 Sep 30;14:1684495. doi: 10.3389/fcell.2026.1684495. PMID: 42877069; PMCID: PMC13661999.

Mapping the exposome of Zimbabwean preschool-aged children using a novel peptide microarray approach

Immune responses vary substantially between individuals and populations, reflecting differences in genetics, environment, and cumulative antigenic exposures. Characterizing these exposures, or the immunological exposome, is essential for understanding population-specific immune development, susceptibility to infection, and responses to interventions.

Researchers from the School of Biological Sciences present a proof-of-concept study applying a bespoke high-density peptide microarray to map the exposome of Zimbabwean preschool-aged children. Researchers profiled immune responses against different peptides.

Beyond vaccine-associated responses, children exhibited diverse and highly heterogeneous antibody profiles, with strong reactivity to enteroviruses, Streptococcus spp., S, pneumoniae, Clostridium perfringens, Clostridioides difficile, and the zoonotic pathogen Ehrlichia canis.

These findings demonstrate the feasibility of high-throughput serological exposome mapping in African children and provide the first detailed characterization of the childhood immunological exposome in this setting.

Citation: Benos EJ, Pfavayi LT, Osakunor DNM, Mduluza T, Mutapi F. Front Immunol. 2026 Oct 1;17:1915960. doi: 10.3389/fimmu.2026.1915960. PMID: 42936571; PMCID: PMC13699487.

Real-world evidence on maternal RSV vaccination uptake, effectiveness, and safety: a systematic review and meta-analysis

Maternal vaccination against respiratory syncytial virus (RSV) is available to protect infants during their most vulnerable early months. As the vaccine is rolled out globally, researchers continue to investigate vaccine uptake, effectiveness, and safety outcomes to inform future research and implementation strategies.
 
From November 2024 to November 2025, researchers from the Usher Institute and Centre for Inflammation Research conducted monthly searches of Ovid databases to identify studies reporting real-world evidence on maternal RSV vaccine uptake, effectiveness, and safety.
 
Researchers estimated an overall uptake of 27.1% through the seasonal vaccination programme during the 2023/24 RSV season in the United States. The pooled vaccine effectiveness against RSV-associated infection hospitalisation in infants younger than six months was 73.6%.
 
Researchers concluded that the maternal RSV vaccination is effective in preventing RSV-associated LRTI hospitalisation during the first six months of life.

Citation: Evelyn Balsells, Sohail Ferdous, Daira Trusinska, Bohee Lee, Louise Lansbury, Cedric Burden, Antonia Ho, Thomas Williams, Francisco Nogareda, Cheryl L. Gibbons, John Allotey, Kimberly Marsh, Louisa Pollock, Asma Khalil, Wei Shen Lim, Ting Shi, The Lancet Regional Health - Europe, 2026, 101847, ISSN 2666-7762, https://doi.org/10.1016/j.lanepe.2026.101847.
 

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