Search

In order to gain knowledge on the quantity of seed dispersed and the contribution of small diurnal primates in the ecosystem, a preliminary study on four species of monkeys was carried out in the northeastern part of the Moukalaba-Doudou National Park in Gabon. The aim was to identify the species of fruits which are dispersed and the animal biomass in two large groups of monkeys namely mangabeys (Cercocebus torquatus and Lophocebus albigena) and guenons (Cercopithecus cephus and Cercopithecus nictitans). Using the reconnaissance walking method, we followed old tracks and dung piles were collected after direct observation of the little monkeys and in the sleeping site. The dung piles were washed, and the seeds collected were identified. A total of 104 fecal samples from the four species of monkeys were collected. Seeds from 19 species of plants were found in the dung piles. The majority of the seeds found in droppings were seeds of Cissus dinklagei and Musanga cecropioides. Cercopithecus nictitans dispersed seeds of more plant species than the others. All the results obtained show that the monkeys disperse an average of 1,114 seeds per day. In this study guenons disperses more fruit than the mangabeys who have a more varied diet. These results suggest that monkeys of Moukalaba-Doudou disperse fewer seeds compared to monkeys in other sites in Africa. Afin d’avoir une connaissance sur la quantité de graine dispersée et la contribution des petits primates diurnes dans l’écosystème, une étude préliminaire sur quatre espèces de singes a été réalisée dans la partie nord-est du Parc National de Moukalaba-Doudou au Gabon. L’objectif était de connaître les espèces de fruits dispersées et la biomasse animale chez deux grands groupes de singes à savoir les mangabeys (Cercocebus torquatus et Lophocebus albigena) et les guenons (Cercopithecus cephus et Cercopithecus nictitans). En utilisant la méthode de la marche de reconnaissance, nous avons suivi d’anciennes pistes et les tas de fumier ont été ramassés après observation directe des petits singes et dans les dortoirs. Les crottes ont été lavées et les graines récoltées ont été identifiées. Un total de 104 échantillons fécaux des quatre espèces de singes a été collectés. Les graines de 19 espèces de plantes ont été trouvées dans les excréments. Cercopithecus nictitans a dispersé plus d’espèces de graines que les autres. La majorité des graines trouvées dans les déjections étaient des graines de Cissus dinklagei et Musanga cecropioides. L’ensemble des résultats obtenus montre que les singes dispersent en moyenne 1114 graines par jour. Dans cette étude les guenons dispersent plus de fruits que les mangabeys qui ont une alimentation plus variée. Ces résultats suggèrent que les singes de Moukalaba-Doudou dispersent peu de graines en comparaison aux singes d’autres sites en Afrique.&nbsp

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.

Foot-and-mouth disease (FMD) is an economically important viral disease of domestic animals and wildlife. High circulation occurs during outbreaks but little is known about the current transmission dynamics in sedentary cattle and sheep herds. To investigate on this, samples from cattle and sheep located in the Vina Division of the Adamawa region of Cameroon, during FMD outbreaks were collected. Non-Structural Protein (NSP) and antigen detecting/serotyping FMD ELISAs were used for sample screening. The NSP serological data of cattle was used to estimate transmission parameters in catalytic and reverse catalytic models. The Akaike’s Information Criteria (AIC) revealed the reverse catalytic model as the most parsimonious for the NSP serological data and was used to estimate the force of infection (FOI), the rate of waning immunity and to estimate historic periods of sustained transmission. Four serological types of FMD notably O, A, SAT 1 and SAT 2 were identified from cattle vesicular epithelia tissues. Seroprevalence findings revealed 65.14% and 15.71% FMDV antibodies in cattle and sheep respectively with highest prevalence in both populations occurring in Mbidjoro. The FOI (λ) in sedentary herds was constant; the rate of waning immunity (ω) was 0.32 meaning cattle are generally immune for 3.12 years post natural infection. The reproductive number (Rt) was 7.33, meaning approximately 87% of cattle always need to be effectively immunized to prevent outbreaks. Therefore, FMD circulates in sedentary cattle and sheep populations in the study area with four serological types detected in cattle.

The aim of the study was to determine the abundance and diurnal activity rhythm of Stomoxyinae at the Ivindo National park and its environs, 14 Vavoua traps were set-up during the rainy season (25th Sept-5th Oct and 21st Oct-9th Nov 2018), in two habitats: the forest, a part of the Ivindo National Park (INP) and village-Town. In the Village-Town habitat, 62141 Stomoxys were caught and regrouped under five species notably 36502 S. omega (58.74%), 24045 S. n. niger (38.69%), 1312 S. xanthomelas (2.11%), 265 S. n. bilineatus (0.43%) and 17 S. calcitrans (0.03%). At the INP, 4645 Stomoxys were caught and regrouped under four species notably 2364 S. n. niger (50.89%), 2153 S. omega (46.35%), 114 S. xanthomelas (2.45%) and 14 S. n. bilineatus (0.30%). Stomoxys were more abundant in the village (517.84 s/t/d) as compared to the INP (44.24 s/t/d). There was a statistically significant difference (P

The abundance, species diversity and diurnal activity rhythm of hematophagous glossineswere evaluated by trapping using 15 Vavoua traps, during the rainy season (25th Sept-5th Oct to 21st Oct-9th Nov 2018), in two habitats: secondary forest and Anthropised milieu, in the biosphere reserve Ipassa-IRET Makokou in Gabon. In total, 489 glossines were caught with 245 collected from Village-Town site and regrouped under 4 species [G.p.palpalis (32.17%), G. frezili (36.23%), G. nashi (29.57%) and G. f. fuscipes (2.03%)] while 244 were collected from forest and regrouped under 3 species [G.p.palpalis (61.48%), G. nashi (28.69%) and G. frezili (0.84%)]. The abundance of glossines was higher in the Village-Town milieu (2.88 g/t/d) as compared to the forest (2.34 g/t/d) with no statistically significant difference (P>0.05). Glossines showed a unimodal diurnal activity rhythm with peak between 10h-12h in the two milieu and was dominated by females.

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

Stable flies (Stomoxys spp.) are common pests of livestock in the peri-urban rangelands of Vina Division of the Adamawa Plateau. No documented information is available on their diurnal dynamics in relation to physiological age and landscape. The main aim of this study was to determine the trap apparent density (ADT) of Stomoxys and associate it to their diurnal activity rhythm and landscape. Vavoua traps (n=12) were used for Stomoxys collection. Trapping was carried out for seven days i.e. three days consecutively in August and four days consecutively in October, 2016. Three traps were pitched in each of the three biotopes (river, cattle corral and gallery forest) of the four study sites (Galim, Mbidjoro, Velambai and Soukourwo). All female Stomoxys captured underwent ovarian dissection for the determination of their physiological ages (parous or nulliparous). A total of 218 Stomoxys were caught and identified into four species (S. niger niger, S. omega, S. calcitrans, and S. xanthomelas) with an overall ADT of 2.59 flies per trap per day and Stomoxys niger niger (1.13 s.n.n. per trap per day) recorded the highest ADT. Species richness was study site dependent. Higher catches of females 113 (51.83%) were made than that of their male 105 (48.17%) counterparts. Galim recorded the highest Stomoxys apparent density (4.90) as compared to other sites with a statistically significant difference (P

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.

The rangelands of the Vina Division on the Adamawa Plateau are densely infested with Stomoxyinae, but little is known about their species composition and ecology. A trap-transect survey was carried out in three villages: Galim, Mbidjoro, and Velambai, using Nzi (n = 3), Vavoua (n = 3), and Biconical (n = 3) traps, all baited with octenol. Three traps of each trap type were set in each of the study villages, and collections were carried out daily. In total, 3,762 Stomoxys spp. were collected from October 2016 to June 2017 and identified using standard keys into five species: Stomoxys niger niger, S. calcitrans, S. niger bilineatus, S. omega, and S. xanthomelas. Galim recorded the highest apparent density of stomoxyines (30 stomoxyines/trap/day) with a statistically significant difference (p<0.05). The Vavoua trap was an ideal tool for Stomoxyinae collection. Stomoxyines abundantly occurred at the end of the dry season (March 2017) and beginning of the rainy season (May 2017). The monthly rainfall positively influenced monthly ADTs of Stomoxyinae. Their diurnal biting activity was bimodal in the rainy season and unimodal in the dry season. The daily activity peak was between 14 h and 16 h with a mean temperature of 31°C, a mean wind speed of 1.5 m/s, and a mean humidity of 50%. The daily trap catch was positively influenced by temperature and wind speed but negatively influenced by rainfall and air humidity. Weather variables influenced Stomoxys spp. monthly and daily ADTs.

Objectifs : Dans le but de connaitre les animaux fréquentant les clairières (ou Baï) forestières au Gabon, une étude sur la fréquentation du Baï de Momba par les grands mammifères a été conduite durant la petite saison des pluies pendant deux mois du 19 février au 13 mars 2012.Méthodologie et résultats : La méthode du scan sampling de Turkalo et Fay (1995) et les fiches de collecte des données proposées par Laws et al. (1975) et par Lee et Moss (1995) ont été utilisée pour recueillir les informations sur les grands mammifères fréquentant le Baï de Momba. Au total, 378 animaux repartis en 9 espèces ont été observée dans cette clairière. Ces espèces ont été représentées par Loxondonta africana cyclotis ; Tragelaphus spekei ; Haliaeetus vocifer, Syncerus caffer nanus, Tomistoma schlegelii, colobus guereza, cercopethecus nictitans, Aonyx congica et Scopus umbetta. Loxondonta africana cyclotis et Tragelaphus spekei ont représenté plus de la moitié des observations avec un taux de fréquentation total de 62,4%. Les autres espèces ont été faiblement observées.Conclusion et application : Il ressort de cette étude que le Baï de Momba est un pôle de centration animale en particulier pour les éléphants et les sitatungas qui y trouvent toutes les conditions idéales pour leur survie. Aussi, il est fort important qu’une étude approfondie dans le temps sur ces animaux de ces milieux soit conduite en vue de leur meilleure valorisation sur le plan écotouristique et dans la perspective de l’aménagement des zones humide à fort potentiel de conservation de la biodiversité.Mots clés : Baï de Momba, Gabon, Loxondonta africana cyclotis, Tragelaphus spekei, Syncerus caffer nanus.

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.