Ethnobotanical survey of plant mosquito repellents: Knowledge, utilization, and application methods for malaria prevention in the Rwenzori Region, Western Uganda

This study documents the widespread use of locally available plants, particularly *Cymbopogon citratus*, *Rosmarinus officinalis*, and *Eucalyptus* spp., as mosquito repellents in the Rwenzori Region of Uganda, highlighting community knowledge and application methods that could inform future malaria prevention strategies.

The Gist

Imagine the Rwenzori region in Western Uganda as a bustling neighborhood where the biggest troublemaker isn't a noisy neighbor, but a tiny, invisible one: the malaria-carrying mosquito. While the world has high-tech tools to fight these pests, many families in this area don't have easy access to them. Instead, they've turned to their own backyard for help, treating their gardens like a natural pharmacy.

This study is essentially a "neighborhood survey" conducted between June and December 2024. The researchers went door-to-door in seven districts and one city, chatting with 173 heads of households to see what they were doing to keep mosquitoes away. Think of it as taking a census of the community's secret weapons against the night-biting bugs.

What They Found
The survey revealed that the community is very much in tune with nature's defenses. A massive 86% of the people interviewed said they use plants to repel mosquitoes. Even more impressive, 55% of them rely only on these plants, ignoring other methods entirely. It's as if the entire neighborhood has decided to trust their garden over a store-bought spray.

When asked which plants are the "stars of the show," three names came up most often:

1. Lemon Grass (Citronella): The undisputed champion, used by nearly 40% of people.
2. Rosemary: The runner-up, favored by about a quarter of the respondents.
3. Eucalyptus: The third most popular choice, also used by about a quarter of the community.

How They Use Them
The study also looked at the "how-to" of this natural defense. The most common strategy is like creating a green moat: 51% of people simply plant these repellent bushes right around their houses, creating a living barrier.

The second most popular method is like hanging a "Do Not Disturb" sign made of leaves. About 28% of people take branches or leaves, bruise them to release their scent, and hang them in windows and doorways to keep the bugs from entering. Some others take a more active approach, like burning the plants, crushing them, or rubbing their oils on the skin, but these are less common than the planting and hanging methods.

The Bottom Line
The main takeaway from this paper is simple: People in the Rwenzori region are already experts at using local plants to fight mosquitoes. The study successfully mapped out what they use and how they use it.

However, the paper stops short of saying these plants are a guaranteed cure-all. The researchers are careful to note that while we now know what the community is doing, we still need to run more tests to see if these plants actually stop mosquitoes from biting or if they truly prevent malaria in a scientific, medical sense. For now, this study is just a detailed inventory of the community's current, nature-based toolkit.

Technical Summary

Technical Summary: Ethnobotanical Survey of Plant Mosquito Repellents in the Rwenzori Region

Problem Statement
Malaria continues to pose a significant public health challenge in Uganda, with rural populations facing particular difficulties due to limited access to conventional vector control tools. While communities in these areas frequently rely on locally available flora as mosquito repellents, there is a notable scarcity of documented data regarding the specific plant species utilized, the extent of their adoption, and the specific application methods employed. This knowledge gap is particularly pronounced in the Rwenzori region of Western Uganda, where the efficacy and practices of traditional plant-based interventions remain largely unrecorded.

Methodology
To address this gap, a community-based cross-sectional study was conducted between June and December 2024 across the seven districts and one city comprising the Rwenzori region. The study employed a multi-stage sampling technique to select 173 household heads as participants. Data collection utilized a pre-tested questionnaire administered via KoboCollect, which had been translated into local languages (Runyoro, Rutooro, and Lukonzo) to ensure accurate comprehension. The collected data were subjected to descriptive analysis using SPSS version 23 to quantify utilization rates and categorize application methods.

Key Results
The survey revealed a high prevalence of plant-based mosquito repellent usage within the region:

• Utilization Rates: 86% of respondents reported using plant-based repellents, with 55% of households relying exclusively on these botanical methods rather than conventional tools.
• Dominant Species: The three most frequently cited plants were Cymbopogon citratus (citronella/lemon grass) at 39.9%, Rosmarinus officinalis (rosemary) at 25.7%, and Eucalyptus spp. at 24.3%.
• Application Methods: The primary strategy involved planting repellent vegetation around the perimeter of the house (51.4%). The second most common method was hanging injured or crushed plant parts in windows and doorways (28.4%). Additional practices included burning or crushing plant parts and the direct application of plant extracts or oils.

Key Contributions
This study provides the first comprehensive documentation of community knowledge and practices regarding plant-based mosquito repellents in the Rwenzori region. It specifically identifies the most utilized species and details the traditional methods of application currently in use. By cataloging these local practices, the research establishes a foundational dataset that can inform future integrated vector management (IVM) strategies, potentially bridging the gap between traditional ecological knowledge and formal public health interventions.

Significance and Claims
The authors position the study as a critical step toward understanding local resource utilization for malaria prevention. However, the paper maintains a modest scope regarding its conclusions. It explicitly states that while the study documents what is being used and how, it does not yet validate the biological efficacy of these methods. Consequently, the authors assert that further research is required to evaluate the specific entomological and epidemiological effectiveness of the identified plants and their application methods before they can be formally integrated into broader vector control programs.