The Republic of Guinea has faced an important challenge with human African trypanosomiasis (HAT), which was endemic over the last century. After initial control in the 1960s-1970s, HAT resurged in the 1990s along the Guinean coast, driven by economic and demographic pressures on the mangrove ecosystem. In response, the Guinean government established a national control program in 2002, focusing on medical mass screenings. In 2012, vector control using tiny targets was introduced in the East Boffa focus to reduce fly density and human-vector contact. However, the Ebola epidemic from 2013 to 2016 disrupted these efforts, leading to a reliance on passive screening. Resuming screenings in 2016-2017 revealed increased cases in all foci except the East Boffa area, where vector control had been effective. Vector control continued during the SARS-CoV2 pandemic and at the same time targeted door-to-door screenings were introduced to target high-risk individuals. Since 2018, around 30,000 at-risk individuals have been screened annually. These strategies reduced the total number of new cases below 1 per 10,000 inhabitants in endemic areas over the period 2019-2023, allowing to validate the elimination of HAT as a public health problem. The Guinean team and partners then focused on systematic spatial monitoring of patients and community engagement in vector control. The program also integrates control of other neglected tropical diseases and addresses new research questions, especially about anatomical and animal reservoirs for parasites. These efforts, combined with implementation of improved diagnostic tests and new oral treatments, through active involvement in multiple clinical trials and studies, now aim to interrupt HAT transmission by 2030.
Every year, over 700,000 people, particularly children under five, die from vector-borne diseases worldwide. Effectively controlling endemics and preventing new outbreaks requires an integrated approach that can lead to the elimination of both vectors and diseases. In the last two decades, integrating medical interventions and vector control has significantly reduced the incidence of Gambian Human African Trypanosomiasis (g-HAT), with the World Health Organization validating eight countries as having eliminated the disease as a public health problem. However, elimination of the tsetse vector has not been confirmed, leaving the possibility of re-emergence. We developed a six-step modeling framework to assess vector elimination by calculating: i) the probability of vector capture; ii) the probability of observing a series of zero catches, even without actual elimination; iii) the probability of natural elimination; iv) the probability of failing to detect a rebound; v) the reinvasion risk; and vi) the sensitivity analysis. Our case study is g-HAT in Mandoul, Chad, and the elimination of Glossina fuscipes fuscipes. We used vector control from 2014 to 2025 with no tsetse detected since 2018. We cannot yet conclude, with over 90% confidence, that tsetse has been eliminated from Mandoul, nor that any remnant population will be naturally eliminated. However, since vector control stopped in April 2025, we estimate that with continued sampling over the next 2 y, and no tsetse detected, elimination could be demonstrated with 99% confidence. Our multistep modeling framework can be applied to other vectors, providing policymakers with guidelines for ongoing and future efforts.
Nile tilapia is a key aquaculture species and a valuable model for climate change research due to its genetic and temperature-dependent sex determinism. Environmental factors, mainly temperature, induce phenotypic sex reversals, resulting in atypical individuals including XX males. Knowledge of morphological variability and sexual genotype makes it possible to better orient genetic selection programs for this species. The objective of this study is to perform a cross-analysis of the morphological parameters and sexual genotype of male from two natural populations of Nile tilapia in Burkina Faso. The study included 30 males from Lake Kou and 30 males from Lake Tengrela. Sexual genotyping with four chromosomic amh markers revealed 70% XY males, 26.67% XX males, and 3.33% YY males in the Kou population, while the Tengrela population consisted entirely of 100% XX males. A total of 25 metric variables, 6 meristic variables, 3 weight-related with significant difference found in 12, 3 and 2 respectively between XX and XY males within and between the two populations. Principal component analysis (PCA) differentiated XY males (Kou) from XX males (Tengrela) but not XY and XX males within Kou population. Length-weight relationships indicated that XY and XX males from the Kou population exhibited positive allometric growth, whereas XX males from Tengrela showed negative allometric growth. These results are promising for genetic improvement and biodiversity conservation programs for natural Nile tilapia populations in Burkina Faso. They are also a contribution to the understanding of sex determination in natural populations of Nile tilapia.
Tsetse flies (Diptera: Glossinidae) are vectors of human and animal trypanosomes. The Glossina palpalis gambiensis Burkina Faso (BKF) colony, established in 1972 and rejuvenated once in 1981, is a long-standing closed colony used extensively for research and vector control. While its performance and competitiveness for sterile insect technique (SIT) programs are regularly monitored, its vector competence (VC) data are outdated. This study aimed to update the VC data of this 47-year-old colony (from the onset of experiment in 2019) against Trypanosoma congolense and T. brucei brucei in laboratory conditions using trypanosome clone and tsetse fly individuals from the BKF colony. Vector competence was studied by infecting rats with T. congolense IL1180 and T. b. brucei BE8P2P2, on which tsetse flies received their first blood meal. Dissections were subsequently performed at different time intervals. Following experimental infections with T. congolense IL1180, 10.58
In Burkina Faso, livestock feeding during the dry season is constrained by recurrent quantitative and qualitative deficits of available fodder biomass, a challenge further exacerbated by climate change. One promising strategy to mitigate these shortages is the use of vegetable crop residues (VCR) as supplementary fodder, particularly in areas with intensive vegetable production. This study aimed to characterize the practices of VCR utilization in the vegetable-growing region of Guiriko, in western Burkina Faso. A survey was conducted using a structured questionnaire among 243 farmers in the locality. Principal component analysis followed by hierarchical clustering was used to classify farmers according to their agricultural and livestock practices. This analysis revealed three distinct groups: market gardeners, agro-pastoralists, and livestock farmers. VCR were widely used across all groups as animal feed, with green bean haulms (GBL: 100%) and sweet potato vines (100%) being preferred by nearly all producers. Cucumber residues were also commonly used, particularly by market gardeners (p < 0.05). Most VCR were offered through open grazing, while GBL and cabbage leaves were more frequently dried prior to be stored and fed in barns, especially by agro-pastoralists. Sweet potato vines were often sold and transported to Bobo-Dioulasso for use in urban livestock systems. VCR were primarily allocated to weak livestock, lactating cows, draft animals, and calves, underscoring their functional importance in smallholder systems. These findings highlight the potential of VCR recycling as a means to alleviate dry-season fodder shortages and to support integrated crop-livestock management. Further laboratory analyses are recommended to determine the chemical composition and nutritional value of these residues, which would inform better feeding strategies, improve animal productivity, and contribute to reducing greenhouse gas emissions per unit of livestock product.
