Research Focus: From pathogens in deer to global antimicrobial resistance policy

Cryptosporidium spp. and Giardia duodenalis are zoonotic pathogens that cause intestinal disease in humans and animals.

Researchers from the Moredun Research Institute aimed to identify the speicies of these two pathogens in Scottish wild deer populations.

Researchers collected fecal samples from four deer species across the country. 

They found Cryptosporidium in 12.3% of samples and Giardia in 7.9%. Infection rates varied by species, with male deer and wet seasons showing higher rates. Particularly, roe deer and young deer had higher infection levels. Co-infections were rare. 

While these pathogens are present in deer, their impact on transmission to humans or livestock is still uncertain.

Citation: Bartley PM, Hamilton CM, Thomson J, Bacchetti R, Mitchell MC, McNeilly TN, de Melo RPB, Hayward AD, Katzer F, Wells B. Vet Parasitol. 2025 Sep 20;340:110614. doi: 10.1016/j.vetpar.2025.110614. Epub ahead of print. PMID: 40992337.

Using two cutting edge methods, bulk RNA sequencing and single cell RNA sequencing, researchers at the Roslin Institute examined human blood immune cells to uncover how they respond to Toxoplasma gondii, a parasite that infects over a billion people worldwide.

They found that the parasite was mainly found in dendritic cells. Interestingly, some monocytes begin to take on dendritic cells-like during infection, changing their patterns of gene in response.

The study also revealed that not all infected dendritic cells respond in the same way, instead, they have distinct gene activity patterns. These differences may be crucial in determining how the disease develops and highlight potential genes and cells that could be targeted for new treatments.

Citation: Chandrasegaran P, Faydaci B, Shih B, Hassan MA. Front Immunol. 2025 Jun 24;16:1582645. doi: 10.3389/fimmu.2025.1582645. PMID: 40630957; PMCID: PMC12234285.

Schistosomiasis is a major parasitic disease that affects millions of people worldwide, especially in sub-Saharan Africa.

Researchers from the Institute of Ecology and Evolution examined 287 individuals in a high-risk community in Uganda, aged 3–74 years, using stool and urine tests to detect Schistosoma mansoni infection and abdominal ultrasound to assess liver damage and other health complications.

Surprisingly, they found that even at very low S. mansoni infection levels, young children had significant liver-related complications and anaemia. Additionally, current malaria infection was strongly linked to anaemia and liver abnormalities, indicating the complexity of co-morbidity in co-endemic areas.

The findings suggest that the current World Health Organization thresholds for defining disease severity do not provide an accurate picture of the true burden of schistosomiasis, particularly in young children and in regions of co-endemicity with malaria. 

Citation: Lim RM, Lahoti R, Clark J, Arinaitwe M, Anguajibi V, Alonso S, Nankasi A, Besigye F, Atuhaire A, Pedersen AB, Webster JP, Lamberton PHL. PLoS Negl Trop Dis. 2025 Sep 3;19(9):e0012750. doi: 10.1371/journal.pntd.0012750. PMID: 40901843; PMCID: PMC12407471.

Researchers from the Usher Institute, in collaboration with Imperial College London, the University of Oxford, and Public Health Scotland, investigated real-world evidence on the effectiveness and safety of nirsevimab, the RSV maternal vaccine, and RSV vaccines for older adults.

Drawing on data from 50 reports covering approximately 7.6 million people, they found that nirsevimab demonstrated around 80.7% effectiveness against RSV-related hospital visits and had a favourable safety profile. RSV vaccines for older adults showed 79.6% effectiveness, with fewer than 10 Guillain-Barré syndrome cases reported per million doses, although the evidence was limited. For the RSV maternal vaccine, no effectiveness data were available by the date of search (10 March 2025); however, no severe adverse events were reported, albeit with limited evidence.

The study confirmed the high effectiveness of nirsevimab and RSV vaccines for older adults, as well as the favourable safety profile of these immunisation products in real-world conditions.

Citation: Lee Bohee, Trusinska Daira, Ferdous Sohail, Pei Ruonan, Kwok Harley H Y, Schwarze Jürgen, Williams Thomas Christie, Gibbons Cheryl, Quint Jennifer K, Sheikh Aziz, Drysdale Simon, B Shi Ting Thorax, 10 September 2025. doi: 10.1136/thorax-2025-223376

In areas that are endemic for the parasitic worm infection schistosomiasis, people are repeatedly reinfected - but we still don’t fully understand how immune responses develop in these cycles.  

In this exploratory immunological study, researchers from the Institute of Immunology and Infection Research investigated the specific (cellular and cytokine) immune response in people during repeat infection, comparing individuals naturally infected with schistosomes in endemic areas to repeat controlled human infection (CHI) in volunteers in the Netherlands. 

The results show that CHI induces host immune responses that broadly resemble those of naturally infected endemic individuals.  This shows that CHI provides a relevant, precise and tractable approach to complement and inform natural infection studies which should be invaluable for better fundamental understanding of immune responses during schistosomiasis, as well as provide proof-of-concept data for future vaccine development.

Citation: Driciru E, Koopman JPR, Steenbergen S, Sonnet F, Stam KA, Bes-Roeleveld L, Iliopoulou E, Janse JJ, Sijtsma J, Nambuya I, Hilt ST, König M, Kruize Y, Casacuberta-Partal M, Egesa M, van Dam GJ, Corstjens PLAM, van Lieshout L, Mpairwe H, MacDonald AS, Yazdanbakhsh M, Elliott AM, Roestenberg M, Houlder EL. Nat Commun. 2025 Jul 24;16(1):6827. doi: 10.1038/s41467-025-62144-8. PMID: 40707512; PMCID: PMC12290099.

This study highlights problems in naming bacteria, especially those causing diseases. 

Researchers from the Microbial Pathogenomics Laboratory have identified three issues that are complicating things: new bacterial names are being created too frequently, databases prefer the latest names, and it's hard to revert to old names. This causes confusion, especially for well-known pathogens. 

To solve this, the researchers suggest using "subgenus" names to minimize disruption. This means new genera from certain splits could become subcategories, helping maintain stability and clarity. They demonstrate this approach with recent changes in bacteria like Mycobacterium.

Citation: Val-Calvo J, Scortti M, Göker M, Vázquez-Boland JA. Int J Syst Evol Microbiol. 2025 Sep;75(9):006917. doi: 10.1099/ijsem.0.006917. PMID: 40981605; PMCID: PMC12451644.

Researchers from the Tackling Infections to Benefit Africa (TIBA) Partnership and Institute of Immunology and Infection Research have been looking into the parastic disease Urogenital schistosomiasis. This disease is contracted from a parasite and is treated with the drug praziquantel (PZQ).

There have been hotspots of this disease identified in multiple African countries, but have yet to be identified in Zimbabwe.

This study examined two hotspot types: areas with high infection rates and those with low cure rates.

High initial infection levels were linked to hotspots. The study suggests that relying only on medication isn't enough, and additional efforts like improving sanitation and snail control are needed for better disease management.

Citation: Mduluza T, Zdesenko G, Tagwireyi P, Jones CM, Mutapi F. PLoS Negl Trop Dis. 2025 Sep 24;19(9):e0013546. doi: 10.1371/journal.pntd.0013546. Epub ahead of print. PMID: 40991670.

Researchers from the Usher Institute conducted a systematic governance analysis to identify all publicly retrievable national action plans (NAPs) on antimicrobial resistance. 

Researchers had previously used a governance framework to assess NAPs on antimicrobial resistance available for the period of 2020–21 from 114 countries, finding substantial variation worldwide, they have since expanded this analysis to include the NAPs of more low-income and middle-income countries, to cover the period of 2021–22.

Overall, researchers found that the global response to antimicrobial resistance was greatly affected by the income level of the nation, highlighting global disparities in antimicrobial resistance governance capacity.

Citation: Patel, J., Moghaddam, S. S., Ranganathan, S., Vezeau, N., O’Neill, E., Harant, A., Stolpe, M., Wieler, L. H., Eckmanns, T., & Sridhar, D. (2025). The Lancet. Infectious Diseases. https://doi.org/10.1016/s1473-3099(25)00406-2