In Gabon, the situation of Human African Trypanosomosis (HAT) remains unclear. In addition, several historical foci existing in many provinces have not been explored for over 15 years. Yet many studies have shown that this country has to offer favorable ecosystems for the development of tsetse major vectors of HAT. To verify a risk of transmission of sleeping sickness, a tsetse inventory was conducted in the province of Ogooué Ivindo historic home of HAT. Vavoua and Nzi traps were placed in four characteristic habitats of the province: National Park Ivindo, Zadié Village, Forest of Zadié and baï (clearing) of Momba. A total of 2383 flies were captured: 1680 flies in the clearing of Momba, 437 flies in the primary forest Zadié, 139 in the National Park Ivindo and 12 in Zadié village. Moreover, these flies were divided into 7 species Glossina frezili, Glossina fusca congolensis, Glossina nashi, Glossina palpalis palpalis, Glossina tabaniformis, Glossina fuscipes fuscipes and Glossina tachinoides. Glossina palpalis palpalis (46%) was the most abundant species followed by Glossina fusca congolensis (21%) and Glossina nashi (16%). Glossina fuscipes fuscipes (6%), Glossina frezili (4%), Glossina tabaniformis (4%) and Glossina tachinoides (3%) were the least caught species. These results have shown that the province of Ogooué Ivindo still remains infested by tsetse flies. Also, further study monitoring these insects is essential to clarify the epidemiological importance of these vectors on human health in this province.

There is need for a simple, cheap and efficient collection and control tool for the different stable fly-species in hyper-infested foci. The efficacy of a modified unbaited Vavoua trap (MVT) was compared with an unbaited Nzi as a standard. Each trap model was pitched either inside or outside the cattle overnight pen with rotation taking place after four days for eight days in September 2018 in Ngaoundere. Fly collection was made every 24 hours and sorted using standard identification keys. In total, 2105 hematophagous flies were caught and constituted of 1417 S. niger (89 S.n/t/d), 124 S. calcitrans (8 S.c/t/d), 562 Musca spp. (25m/t/d) and 2 Chrysops distinctipennis (0.1 Cd/t/d). The overall mean catches with the MVT (50.96±57.16) was higher than with the Nzi (27.43±27.73), with no statistically significant difference (t=0.9, df=46.0, P=0.37). Higher mean catches were recorded outside the overnight cattle pen (47.79±55.27) than inside (39.83±55.40) with no statistically significant difference (t=0.5, df=46.0, P=0.62). Stable flies and tabanids were mostly caught outside the overnight stable, while Musca spp. were highly caught inside.Humidity and wind speed were the main drivers of the abundance of the flies caught and from the Pearson's correlation test, there was a negative and significant correlation between the two meteorological parameters (r=-0.29, P=0.04). The MVT can serve as a simple and efficient tool for the survey and control of stable flies in the Adamawa plateau and elsewhere.

An entomological prospection to show the species composition and diurnal activity of tabanids was carried out using 15 Vavoua traps, during the rainy season (25th Sept-5th Oct and 21st Oct-9th Nov 2018), in the secondary forest [Ivindo National Park (INP)] and Village-Town sites in and around the biosphere reserve Ipassa-IRET Makokou in Gabon. In total, 839 tabanids were caught with 747 recorded at INP and regrouped under 11 species of the genus Tabanus [T. taeniola (57.76%),               T. ricardae (26.32%), T. par (5.54%), T. ruficrus (3.74%), T. socius (3.74%), T. disjunctus (2.49%), T. marmorosus (0.28%) and T. obscurehirtus (0.14%)]. However, two species of the genus Chrysops [C. dimidiatus (70.83%) and C. silaceus (29.17%)] and one species of the genus Haematopota [H. pluvialis (100%)] were only identified at INP. While in the Village-Town sites, 92 tabanids were caught and regrouped under five species of the genus Tabanus [T. ruficrus (14.13%), T. taeniola (9.78%), T. ricardae (73.91%), T. par (1.09%), and T. marmorosus (1.09%)]. Tabanids were more abundant in the forest (7.12 tabanid/trap/day) as compared to the Village-Town (0.77 t/t/d) with a statistically significant difference (P<0.05). At INP, tabanids showed a unimodal activity pattern with peak attained between 12-14H and in the anthropized milieu (14-16H) and dominated by females.

To embark on an anti-vectorial fight against mechanical vectors of animal trypanosomosis, investigations were undertaken in order to determine the abundance, species diversity and daily activity of tabanids in a cattle ranch in Gabon. The nzi and vavoua traps were used to catch tabanids in three divisions of this ranch. In this study, 616 tabanids were captured: 349 (56.66%) in Division 1, 226 (36.69%) in Division 2 and 41 (6.66%) in Division 3. In the first Division, T. taeniola was the most abundant species with an Apparent Density (ADT) of 2.2, followed by H. pluvialis (ADT = 1.05). In the second Division, H. pluvialis was most abundant with ADT of 1.6, followed by T. taeniola (ADT = 0.38). In the last Division, the most abundant species was H. pluvialis (ADT = 0.15). Comparing the relative abundance of catches with sites (Divisions), we realized that there was no statistically significant difference in catches with trapping sites. It was noticed that Division 3 recorded the highest diversity index values. We realized that the nzi trap recorded higher tabanid catches than the vavoua trap. The diurnal activity rhythm of the most frequent species encountered slightly differed with prospection sites.