LLIMA TRIAL · TURKANA, KENYA

Exploring a different route to malaria prevention.

The LLIMA trial is testing whether treating livestock with long-lasting ivermectin can reduce malaria vector populations and malaria cases.

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A ONE HEALTH APPROACH

How could it work?

Livestock are treated with long-lasting ivermectin drug. Mosquitoes take a blood meal from treated livestock and die. LLIMA is testing whether this can sufficiently reduce mosquito numbers and malaria transmission in people.

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Treat livestock

Livestock receive long-lasting ivermectin.

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Mosquito feeds

Mosquitoes take a blood meal from treated animals.

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Reduce survival

Ivermectin ingested from treated animals reduces mosquito survival and reproduction.

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Test malaria impact

The trial measures whether this leads to fewer malaria cases.

01 · THE CHALLENGE

A changing malaria landscape

Pastoralist livelihoods, outdoor exposure and a changing vector landscape mean malaria control needs to fit local realities.

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02 · THE LLIMA TRIAL

Testing the intervention in the real world

LLIMA is an integrated One Health study that will follow malaria cases, mosquitoes, livestock and communities across a 3-year period.

How the trial works →

03 · WHERE WE WORK

Turkana County

The study is based in pastoralist communities in Turkana, where people and livestock live in close contact.

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Cow hide used as an outdoor sleeping space in Turkana

Outdoor sleeping space in the study setting

ABOUT LLIMA · THE CHALLENGE

Malaria control designed around local realities

LLIMA stands for Long-Lasting ivermectin in livestock for malaria control in Kenya in response to Anopheles stephensi invasion. It is a UKRI-MRC funded four-year project evaluating long-lasting ivermectin-based livestock mass drug administration as a novel intervention against malaria in pastoralist settings of Turkana County, Kenya.

Turkana faces a rapidly growing malaria burden, with pastoralist and refugee communities disproportionately affected. Local realities challenge interventions focused mainly on indoor exposure: people may sleep or spend substantial time outdoors, livestock are kept close to households, and mobility changes with seasons and grazing conditions.

LLIMA therefore investigates a complementary approach aimed at mosquitoes that feed on animals. The arrival of invasive vectors, including Anopheles stephensi, adds urgency: this vector can exploit urban and peri-urban environments, bite outdoors and feed on animals.

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Boma and landscape in Turkana — Bomas and landscape

Goats in the study setting — Livestock and pastoralist livelihoods

Camel in Turkana landscape — Livestock diversity

Mosquito net placed outdoors beside a household in Turkana — Local behaviours · outdoor sleeping

INTERLINKED RESEARCH

Four work packages, one study

LLIMA integrates human malaria outcomes, mosquito ecology, livestock systems and social context. Each work package informs the others throughout the formative and trial phases.

Epidemiology

Measures symptomatic malaria incidence and prevalence before and after the intervention using community-based active case detection.

Team: Wendy O’Meara, Diana Menya, Marta Maia, Brian Bartilol

Entomology

Characterises Anopheles species distribution, host choice, breeding sites and pathogen infection, and measures the effect of livestock-targeted ivermectin on malaria vector populations.

Team: Kevin Kobylinski, Joseph Mwangangi, Marta Maia, Caroline Wanjiku, Brian Bartilol

Animal ecology

Studies herd size, livestock mobility, husbandry, intervention delivery, animal production and environmental effects.

Team: Eric Fèvre, Keli Gerken, Buke Yussuf

Social sciences

Explores social, cultural, and economic factors shaping implementation, acceptability and integration of One Health interventions for malaria control.

Team: Caroline Jones, Dorothy Oluoch, Truphena Onyango

THE LLIMA TRIAL

A controlled before-and-after study across two malaria seasons

The study evaluates whether mass drug administration of long-lasting ivermectin to eligible livestock reduces symptomatic malaria incidence in people. Intervention livestock receive long-lasting ivermectin twice per year, three months apart; control livestock receive a benzimidazole dewormer known not to have any effect on mosquitoes.

Baseline & site selection

Health-facility data and formative research characterise malaria burden, bomas, livestock systems and community context.

Follow bomas

Thirty bomas per study arm are followed. Community Health Promoters visit regularly and test symptomatic participants with malaria rapid diagnostic tests.

Intervene

Eligible livestock in the intervention arm receive long-lasting ivermectin; control livestock receive a standard benzimidazole dewormer.

Measure impact

Malaria incidence, prevalence, mosquito ecology, livestock outcomes and implementation experience are compared over time.

Livestock in the study setting

STUDY SETTING

Lokichoggio, Turkana County

LLIMA is working in north-western Turkana, a pastoralist setting where livestock mobility, outdoor activity and seasonal ecology shape everyday life and malaria exposure.

Turkana has experienced a marked increase in malaria burden. The Kenya Malaria Strategy 2023–2027 categorises Turkana as a high-burden county, and recent reporting describes a shift from seasonal outbreaks toward endemic transmission, with malaria prevalence reported at 39%.

Insecticide-treated nets remain important, but local realities can limit protection. People may sleep or spend evenings outdoors, and nets used outside can face greater wear than under conventional indoor use. LLIMA is investigating a complementary intervention designed around this pastoralist setting.

Lokichoggio is the focal study area for characterising mosquito ecology and evaluating the livestock-targeted intervention.