Over the last century, the World Health Organization (WHO) has recorded several major human African trypanosomiasis (HAT) epidemics, with the first being in the Uganda Congo Basin from 1896 to 1900 and the last in the late 1990s (1, 2). Trypanosomiasis is a vector-borne disease caused by protozoan parasites transmitted between humans and animals by tsetse flies (Glossina spp.) (3). Recent epidemiological studies have increasingly highlighted the role of climate change in shaping the distribution and incidence of trypanosomiasis (4, 5). Climate-driven changes in temperature and rainfall patterns influence tsetse fly habitats, altering their geographic range and, consequently, disease transmission dynamics (6). Temperature increase has been associated with the contraction of tsetse populations in some regions while expanding their range into previously cooler upland areas (4). The term “climate change” refers to enduring alterations in weather patterns and temperatures that are primarily driven by human actions, such as burning fossil fuels (7, 8). Climate variability refers to short-term, natural fluctuations in climate conditions that occur over months, seasons, or a few years, driven by natural processes within the Earth’s systems (9, 10).

This disease has two known forms: HAT and animal African trypanosomiasis (AAT) (1). HAT, often referred to as sleeping sickness, is caused by the parasites Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. T. b. gambiense leads to a chronic form of the disease and can be found in 24 nations across West and Central Africa, responsible for 92% of the cases reported globally, while Trypanosoma brucei rhodesiense, located in 13 countries of Eastern and Southern Africa, makes up 8% of the reported cases. American trypanosomiasis, commonly known as Chagas disease, is caused Trypanosoma cruzi and transmitted by kissing bugs (Triatominae), primarily occurring in Latin America, which distinguishes it from HAT (1). The major symptoms of HAT are neuropsychiatric, including behavioral problems, personality disorders, sleep disturbances, and coma. If left untreated, this disease can result in death (11).

Climate modelling studies suggest that future warming scenarios may further shift tsetse distributions, increasing the risk of HAT in new regions (5, 12). For example, in Zimbabwe, it is projected that rising temperatures could make cooler highland areas more suitable for tsetse flies, potentially leading to new disease foci (4). The incidence of HAT varies from region to region (13). Multiple studies have established that tsetse flies are found in sub-Saharan Africa and that only specific species are responsible for transmitting the disease (14–16). The disease has a focal distribution ranging from single villages to entire regions, and its incidence can vary from one village to the next. HAT primarily poses a risk to communities in isolated rural locations that have restricted access to healthcare, making its identification and treatment more difficult (17). War, displacement, and poverty also affect these populations, favoring transmission (18). Studies have demonstrated that climate variability interacts with land-use changes to influence tsetse fly abundance (5). For example, deforestation and agricultural expansion have reduced tsetse habitats in some areas, while climate-induced vegetation and water availability shifts have created new breeding sites elsewhere (4). Such dynamics complicate control efforts, necessitating adaptive strategies that account for both climatic and anthropogenic drivers.

Since 2001, the WHO has engaged in several control strategies to ensure that the disease is contained and possibly eradicated (1). Public and private partnership-initiated HAT surveillance to ensure appropriate surveillance and response. Active case-finding conducted by mobile teams in villages has been the cornerstone of HAT control since colonial times (19). Despite these efforts, underreporting remains a major challenge, particularly in regions where climate variability has altered disease patterns (20). A study in Uganda found that 93% of HAT-related deaths were unreported, highlighting gaps in surveillance (21). This underreporting is exacerbated in areas where climate shifts have led to unexpected outbreaks, overwhelming local health systems. The study emphasizes the need for improved reporting systems to better understand and address the burden of this neglected tropical disease.

Significant initiatives aimed at managing the disease through various strategies have resulted in a consistent reduction in the number of sleeping sickness cases reported across Africa since the 1930s (11). Over the past five years, the Democratic Republic of Congo (DRC) has indicated that 61% of reported cases (averaging 522 cases per year) in Angola, Central African Republic, Chad, Congo, Gabon, Guinea, Malawi, and South Sudan fell within the range of 10 to 100 cases. Meanwhile, Cameroon, Côte d’Ivoire, Equatorial Guinea, Uganda, Tanzania, Ethiopia, and Zambia have reported between one and ten cases, and sporadic cases have been observed in Burkina Faso, Ghana, Kenya, Nigeria, and Zimbabwe over the last decade (2). The WHO statistics show that the measures taken to eradicate the disease have led to a historic low in HAT occurrences, with fewer than 2000 cases reported in 2017 and under 1000 cases in 2018, staying below the 2022 threshold (2). The projected population at risk during the years 2016 to 2020 was 55 million, with merely 3 million categorized as being at moderate to high risk (2).

As of 2019, it was estimated that the area in Zimbabwe affected by tsetse flies covered 30,000 km², representing 17% of the 180,000 km² that was originally suitable for tsetse fly infestation (17). In Zimbabwe, the more severe version of HAT, which is caused by Trypanosoma brucei rhodesiense, appears irregularly, and the tsetse fly vector cohabits with the human population (17). The latest case of sleeping sickness in humans was noted in 2019. However, some regions of the country with a high malaria burden also exhibit a significant prevalence of sleeping sickness (22). Various species of trypanosomes are harmful to livestock, leading to animal African trypanosomiasis (AAT or nagana) and causing significant production declines (16). Although rising temperatures might account for the decline in tsetse populations in specific regions, research has indicated that higher temperatures could have rendered some cooler, elevated areas in Zimbabwe more conducive for tsetse, potentially resulting in the establishment of new disease hotspots (4). As a result, it is essential to measure the scale and geographic distribution of the shifts in tsetse fly populations and trypanosomiasis. Research has indicated that Human African Trypanosomiasis (HAT) could potentially be reported in colder areas of Zimbabwe due to the chance of tsetse populations and Brucei infections resurfacing in various regions of Southern Africa that were previously thought to be safe (4, 23). One study identified Hwange National Park in Zimbabwe and Kruger National Park in South Africa as high-risk areas for the resurgence of AAT (4).

Over the last century, various tsetse fly control measures have been deployed in Zimbabwe, including bush clearance, wildlife extermination, ground and aerial spraying with insecticides, bait technologies, and the release of sterile insects (16). Nonetheless, the most significant influence on tsetse populations has come from both the organized and unregulated influx of individuals into regions affected by tsetse (2). The clearance of land for agriculture, combined with the use of crop spraying chemicals for cotton and tobacco, has also contributed to reductions in tsetse fly populations in certain areas (16). However, climate variability causes seasonal changes, which, according to previous studies, have resulted in alterations in commonly known suitable areas for the vector, thus causing changes in the distribution of the disease (24–26). This has presented significant challenges, particularly in the management of infectious diseases associated with vectors that have thrived under climate-induced changes in weather patterns, including the rise in temperatures and unpredictable rainfall patterns in Zimbabwe (27–29). Therefore, this study aimed to determine the extent to which these climatic variabilities have occurred and how they affect the distribution of the disease. Areas that have the potential to harbor the vector will be identified so that they can be closely monitored for any incidence of the disease. In addition, there could be a more targeted approach to eradicate the disease in these hotspots. This will reduce costs, leading to a more efficient disease management strategy. While studies have been done around the globe, there is limited literature on the influence of climate variability and change on the incidence and prevalence of trypanosomiasis in Binga district, Zimbabwe. Therefore, this study aims to explore how climate variability and change have affected the occurrence of trypanosomiasis cases within the district. The study will map the distribution of trypanosomiasis, rainfall and temperature patterns over the last 15 years. This study will provide insights that will facilitate trypanosomiasis management interventions in this region.

This study is anticipated to generate a comprehensive analysis of the spatio-temporal dynamics between climate variability and human African trypanosomiasis (HAT) in Binga District from 2000 to 2025. The initial scoping review is expected to synthesize global evidence, firmly establishing the multifaceted influence of climate on trypanosomiasis epidemiology. It will likely confirm that temperature fluctuations directly impact tsetse fly survival, reproduction, and geographic range, potentially contracting habitats in some areas while expanding them into previously cooler uplands. Furthermore, the review is anticipated to highlight the critical role of rainfall patterns, revealing a non-linear relationship where both droughts and extreme precipitation can alter the availability of suitable breeding sites and vegetation cover, thereby affecting vector abundance.

Building on this foundational knowledge, the quantitative analysis of Binga District is expected to reveal distinct temporal and spatial patterns. The analysis of secondary health data will likely show a non-uniform trend in HAT incidence, characterized by peaks and troughs that correlate with specific climatic events rather than a simple linear progression. Concurrently, the remotely sensed climate data is projected to demonstrate a discernible warming trend and increased variability in rainfall over the 25 years. The core of the anticipated findings lies in the spatial analysis. The overlay of disease case maps with climate layers in ArcGIS Pro is expected to reveal a strong spatial coincidence, identifying clear hotspots in areas that have historically maintained optimal microclimatic conditions for tsetse flies. More critically, this analysis is poised to identify emerging risk areas and locations that were previously less suitable but have become more conducive for the vector due to shifting temperature and rainfall patterns, potentially exposing new populations to the disease.

The statistical analysis is predicted to quantify these apparent associations. Regression models are predicted to indicate a statistically significant correlation between HAT case distribution and both temperature and rainfall factors. While the relationship with rainfall may be curvilinear, with moderate levels being most advantageous, the relationship with temperature is probably positive within the vector’s ideal thermal range. The ultimate goal of this research is to create prediction risk maps by combining these statistical and geographical findings. The district’s areas most at risk for HAT transmission in the future under current climate patterns will be predicted by these maps, which will be the main outcome. It is anticipated that these findings will offer a solid body of evidence for developing geographically focused, climate-resilient surveillance and control plans, allowing for more effective and proactive public health initiatives in Binga District.

The findings from this study might enrich the effectiveness of surveillance strategies for trypanosomiasis by identifying the changes brought about by climate variability and change in the disease distribution. Health professionals may use this knowledge to plan for targeted intervention strategies. The study might further result in a predictive map for the occurrence of the disease to be anticipated by factoring in the changes in climate, where conducive environments for the breeding of the vector are being created. However, it is anticipated that the collected data may not accurately represent the occurrence of the disease because sleeping sickness cases are underreported, especially in remote areas with limited access to healthcare.

The research proposal underwent examination by the National University of Science and Technology Institutional Review Board (NUST IRB) to secure approval (NUST/IRB/2024/060) for the study. Modifications to the methodology and data collection instruments were made based on the feedback received. Consent will be obtained from Binga District Hospital for the trypanosomiasis case data recorded between 2000 and 2025. The researcher will also request approval from the Ministry of Health and Child Care (MoHCC) to access records at health facilities and seek permission from local authorities to reach areas where the cases were documented to capture the coordinates. No primary data will be gathered from human subjects, and the associated risks to individuals are deemed minimal. All data collected will be treated with the utmost confidentiality. The data will be anonymized and securely stored within the Kobo Collect toolbox, granting access only to the principal investigators and supervisors, and will solely be used for the academic purposes specified in this protocol.

This study highlights how climate variability and changes influence trypanosomiasis transmission in Binga District, Zimbabwe, revealing shifts in tsetse fly habitats due to changing temperature and rainfall patterns. The findings underscore the need for adaptive public health strategies, including targeted surveillance in emerging high-risk zones, climate-informed vector control, and strengthened cross-sectoral collaboration under a One Health framework. Integrating early warning systems with localized interventions, like community-based tsetse trapping and livestock treatment, can help Zimbabwe reduce the resurgence of diseases driven by climate change. This approach combines proactive monitoring with targeted actions to effectively address the health challenges posed by environmental shifts. Additionally, improving diagnostic capacity in rural health systems and aligning efforts with WHO’s 2030 elimination roadmap will ensure sustainable progress.

The use of secondary data comes with inherent drawbacks, especially when it comes to capturing real-time changes in environmental and socioeconomic factors that could significantly influence disease patterns. For example, modifications in land utilization, farming practices, and inequalities in access to healthcare are vital aspects that may affect the relationship between climate variability and the occurrence of trypanosomiasis; however, these elements may not be accurately reflected in historical data. Additionally, the lack of efficient surveillance tools can impede the precise identification of cases, causing healthcare workers in Binga to rely primarily on clinical symptoms for diagnosis. This dependence on symptomatology carries the risk of misdiagnosis or missing cases, particularly in regions where diagnostic resources are limited.