Rodents, land use, pathogen transmission and spillover

I study how people reshape the landscapes they live in, how small mammals respond, and what effects that has on the viruses they carry. Much of this work is on Lassa fever in West Africa.

The synanthropy gradient, from closed forest to urbanised dwellings An illustrated cross-section of a West African landscape running left to right: closed forest, forest edge and bush with oil palms, agricultural land with crops, rural dwellings of thatched huts beside a mango tree, peri-urban houses with corrugated roofs, and urbanised dwellings of concrete buildings. Beneath it, a fading bar for each of eight small-mammal species shows schematically where along the gradient it is most often found, ordered from forest to town: Malacomys edwardsi in closed forest; Lophuromys sikapusi at the forest edge; Lemniscomys striatus and Praomys rostratus in agricultural land, Praomys reaching into rural dwellings; Mastomys natalensis, the primary reservoir of Lassa virus, peaking at rural dwellings; Rattus rattus around rural dwellings; Mus musculus at peri-urban dwellings; and Rattus norvegicus in urbanised dwellings. The same information is given as a list below this graphic. Closed forest Forest edge and bush Agricultural Rural dwellings Peri-urban dwellings Urbanised dwellings Malacomys edwardsi, a closed-forest specialist Malacomys edwardsi Edward's swamp rat Lophuromys sikapusi, forest edge and bush Lophuromys sikapusi Rusty-bellied brush-furred rat Lemniscomys striatus, agricultural land and grassland Lemniscomys striatus Typical striped grass mouse Praomys rostratus, agricultural land and rural dwellings Praomys rostratus Forest soft-furred mouse Mastomys natalensis, the primary reservoir of Lassa virus, peaking at rural dwellings Mastomys natalensis Natal multimammate mouse Rattus rattus, commensal, rural dwellings Rattus rattus Black rat Mus musculus, commensal, peri-urban dwellings Mus musculus House mouse Rattus norvegicus, commensal, urbanised dwellings Rattus norvegicus Brown rat Increasing synanthropy. Bars show schematically where each species is most often found.
  • Closed forest Forest specialists, with little direct contact with people. Rodent sampling here is rare.
  • Forest edge and bush Regrowth and fallow at the human margin. Small-mammal diversity is expected to peak here.
  • Agricultural Crops and fallow. Wild and commensal species meet where crops add food.
  • Rural dwellings Villages and their gardens, where crop pests peak and spillover is thought to occur.
  • Peri-urban dwellings Invasive commensals may offer new hosts for zoonotic pathogens. Poor infrastructure may increase contact between rodents and people.
  • Urbanised dwellings Few rodent-borne zoonoses are reported from dense cities. Sanitation and human behaviour may limit spillover.

Original illustration, modified with Gemini Flash 3.8 and Claude Opus 5.5.

On the gradient

Research informed by fieldwork: trapping, sampling and serosurveys where land use, rodents and people meet.

  • Host ecology in Sierra Leone

    Four years of small-mammal trapping across the gradient from forest to dwelling, and what land use does to the reservoir community.

  • SCAPES, Nigeria

    Human exposure to Lassa virus at village scale, and the behaviours that generate contact with rodents.

  • Bank voles at Uppsala

    From September 2026, microbial sensors for the contact networks that drive environmental transmission.

  • Surveillance and outbreak response

    Where to sample when resources are finite. Plus earlier work on COVID-19 and mpox.

  • Vaccines and trial design

    Designing trials for pathogens that arrive from wildlife, and the commitments that should govern self-disseminating vaccines.

  • Rodent-borne disease ecology

    Three pillars for prevention: disease ecology, synanthropy and rodentation.

Off the gradient

Computational and other research: synthesis, modelling, tools and the work that sits outside the field.

  • Project ArHa

    A global synthesis of arenavirus and hantavirus sampling in small mammals, and what surveillance bias hides.

  • Lassa fever and cities

    What happens to spillover when the gradient runs into an expanding West African city.

  • Lassa epidemiology

    How many cases there really are, and what the sampling record can and cannot support.

  • Open tools and data

    Map Liberator, SiteTool, and a minimum data standard for wildlife disease research.

  • Consultancy

    Quantitative epidemiology and disease modelling for health organisations and industry.

  • Earlier work

    Antimicrobial resistance, African swine fever, peste des petits ruminants and digital health.

Recent news

  • Grant. Vetenskapsrådet South Korea–Sweden research collaboration, An AI-directed One Health risk prediction framework for active learning in rodent-borne zoonoses, with Chungnam National University, October 2026 to December 2027. More.
  • New paper. The socio-economic shield limits Lassa virus spillover in urban West Africa, in Epidemiology & Infection. More.
  • New preprint. Viral reservoir status in small mammals emerges as a predictable life-history trait. More.
  • Fellowship. Birgitta Sintring Fellowship, Uppsala University, from September 2026. More.