Seasonal study of the relationship between the condition factor and the monogeneans parasite density of Heterobranchus isopterus Bleeker, 1863 and Clarias gariepinus (Burchell, 1822) fished in the Bagoué River (North-Western, Ivory Coast).

A comparative study on the relationship between condition factors and parasite density of Heterobranchus isopterus and Clarias gariepinus was conducted during the wet and dry seasons. Specimens were collected from the Bagoué River from August 2020 to July 2021. Two hundred eighty-four specimens of H. isopterus and 272 specimens of C. gariepinus were collected from all stations during both seasons. The standard length and weight of the fish were recorded and the condition factor was calculated for each individual. The gills were examined under a binocular loupe and the monogeneans were collected. Parasite counts showed that for both host species, the total number of parasites was higher in the dry season than in the wet season (p < 0.05). The correlation coefficient was determined to investigate the relationship between the condition factor and the total number of parasites. A significant positive correlation was observed between the condition factor and the number of parasites in both host species during the wet season. A negative correlation was observed in both hosts during the dry season. The information from this study could be taken into consideration in the sanitary management of the fish farming industry. The dry season could be considered as the season with favorable conditions for the development of most parasite species.

Specific Diversity of Helminth Parasites of the Edible Frog Hoplobatrachus occipitalis (Günther, 1858) in Agricultural Landscapes in the South-East of Ivory Coast, Africa.

OBJECTIVE: This study describes the specific diversity of Helminth parasites of the edible frog Hoplobatrachus occipitalis (Günther, 1858) to assess the rate of infestation in three types of plantations (coconut, palm and banana plantations) in the south-east of Africa. METHODS AND RESULTS: A total of 156 frog specimens were collected in November 2019 from all the plantations and ten parasitic Helminth taxa were recorded. The overall prevalence (93.6%) showed a high infestation of the frog in these anthropized environments. The banana plantations that use the most fertilizers and pesticides had the highest prevalence (95.2%) suggesting pollution-related parasitic load. The number of parasites was higher in female frogs than in males, suggesting a sex-specific immune resistance. This study also highlights the parasite specificity and the sites of Helminth infestations. Trematodes of the genus Haematoelochus and Diplodiscus showed strict specificity in the lungs and large intestine/rectum of the host. The other parasites colonized the digestive tract with a more or less marked specificity. CONCLUSION: Our study provides several elements of response on the population of Helminth parasites of the edible frog Hoplobatrachus occipitalis, with a view to better knowledge, management, conservation and protection.

Two new Quadriacanthus Species (Monogenea: Dactylogyridae) Including a New Geographical Record of Quadriacanthus mandibulatus Francová & Rehulková, 2017, Gill Parasites from Heterobranchus bidorsalis (Siluriformes) in Côte d'Ivoire.

PURPOSE: To study the monogeneans gill parasites of Heterobranchus bidorsalis (Siluriformes, Clariidae) fish of economic interest in the Bagoue River. METHODS: Fifty-five specimens of H. bidorsalis were caught with gillnets in the Bagoué River from August 2018 to January 2019. The monogeneans were individually isolated from the gill and transferred directly onto a slide in a drop of glycerin ammonium picrate mixture (GAP). RESULTS: The new species differ from the previously described Quadriacanthus spp. mainly by the morphology of their sclerotised vagina: Quadriacanthus tanoyaoi sp. nov having a V-shaped, widely open vagina with a central protuberance, and Quadriacanthus bidorsalisi sp. nov having a pear-shaped vagina, composed of a tubular part with a ring near the aperture and a swollen portion. Q. tanoyaoi sp. nov and Q. bidorsalisi sp. nov are different in the shape of the dorsal and ventral anchors (more sturdy for Q. tanoyaoi), of the dorsal and ventral cuneus (triangular vs Y-shaped, respectively), and that of the vagina (V-shaped, widely open with a central protuberance vs pear-shaped, respectively). CONCLUSION: To date, only Quadriacanthus mandibulatus Francová & Rehulková, 2017 were recognised parasitizing from H. bidorsalis from the Nile River Basin (Sudan) and Lake Turkana (Kenya). The present study with the description of 2 new species expands the number to 3 species of monogeneans for this fish.

Checklist and Distribution of Freshwater Cladocera (Crustacea: Branchiopoda) in Côte d'Ivoire (West Africa).

This study provides a checklist of cladocerans and evaluates the species richness and composition of this order in Côte d'Ivoire. A checklist of cladocerans was created by evaluating data from the literature and fauna surveys focused on zooplankton in different types of aquatic environments over the past 50 years. In total, 39 Cladocera species have been reported from Côte d'Ivoire. This richness includes 24 genera and seven families, with Chydoridae being the most diversified family (16 species, 41% of the total Cladocera diversity in Côte d'Ivoire), followed by Daphniidae (eight species, 21%); Moinidae (four species, 10%); Bosminidae, Macrothricidae, and Sidiidae (three species, 8% each); and Ilyocriptidae (two species, 5%). Ceriodaphnia cornuta, Moina micrura, and Diaphanosoma excisum were the most frequently encountered species.

Four New Species of Synodontella Dossou et Euzet, 1993 (Monogenea: Dactylogyridae) Gills Parasites of Synodontis clarias from the Bagoué River (North-Western Ivory Coast).

INTRODUCTION: A survey of monogenean parasites on the gills of Synodontis clarias was carried out in Ivory Coast. Five species of monogeneans were found, of which four are new to science and are newly described here. METHODS: The monogeneans were individually isolated from the gill and transferred directly onto a slide in a drop of glycerin ammonium picrate mixture (GAP). The haptor and the hard part of the copulatory complex were measured and drawings made using Motic BA310 microscope and Motic Image Plus 2.0 and Corel Draw software. RESULTS: Five species of Synodontella including four new to science were described. Synodontella anohmangniae n. sp., Synodontella antoineparisellei n. sp., Synodontella clariasi n. sp. and Synodontella samorossoensis n. sp. differ from the previously described Synodontella species mainly in the morphology of their male copulatory organs (MCO). Synodontella anohmangniae n. sp. is distinguishable by the dorsal transverse bar with a small point at each extremity of the concavity in its central part. Synodontella antoineparisellei n. sp. differs from all other known Synodontella spp. in the morphology of the penis, with an egg-shaped opening in its distal part. Synodontella clariasi n. sp. and Synodontella samorossoensis n. sp differs from all other described congeneric species mainly by the dorsal transverse bar surmounted by a highly sclerotized part.

Three new species of Synodontella (Monogenea, Ancyrocephalidae), gill parasites of Synodontis spp. (Siluriformes, Mochokidae) from Côte d'Ivoire.

Four species of Synodontella, including three new, are reported from three species of Synodontis (S. ocellifer, S. nigrita, and S. velifer) from north-western Côte d'Ivoire. Synodontella melanoptera Dossou & Euzet, 1993 was found on the gills of S. nigrita and S. velifer and was already known from the gills of S. melanopterus in Benin and the gills of S. obesus and S. rebeli in Cameroon. The new species are Synodontella speroadotevii n. sp. from S. nigrita (type-host), S. velifer and S. ocellifer, and Synodontella bagoueensis n. sp. and Synodontella akengboi n. sp., both from S. velifer (type-host for both), S. nigrita and S. ocellifer. The new species differ from the other species of Synodontella mainly in the morphology of their male copulatory organs (MCO): Synodontella speroadotevii has a two-part penis (one being a hollow tube and the other a flattened tube); Synodontella bagoueensis has a wide G-shaped penis with a sub-terminal opening; and Synodontella akengboi has a simple narrow J-shaped penis. Synodontella speroadotevii differs from Synodontella bagoueensis and Synodontella akengboi in the shape of the dorsal transverse bar, which shows no protuberance, and also in the morphology of the MCO. Synodontella bagoueensis differs from the other two species in that it has a dorsal transverse bar that is V-shaped and a G-shaped MCO. Synodontella akengboi differs from the two other species in having a J-shaped MCO and in the size of its ventral and dorsal anchors which, contrary to the other two species, are almost similar.

TITLE: Trois nouvelles espèces de Synodontella (Monogenea, Ancyrocephalidae), parasites branchiaux de Synodontis spp. (Siluriformes, Mochokidae) en Côte d'Ivoire. ABSTRACT: Quatre espèces de Synodontella, dont trois nouvelles, sont signalées chez trois espèces de Synodontis (S. ocellifer, S. nigrita et S. velifer) du nord-ouest de la Côte d'Ivoire. Synodontella melanoptera Dossou & Euzet, 1993 a été trouvé sur les branchies de S. nigrita et S. velifer et était déjà connu des branchies de S. melanopterus au Bénin et des branchies de S. obesus et S. rebeli au Cameroun. Les nouvelles espèces sont Synodontella speroadotevii n. sp. de S. nigrita (hôte type), S. velifer et S. ocellifer et Synodontella bagoueensis n. sp. et Synodontella akengboi n. sp., tous deux de S. velifer (hôte type pour les deux), S. nigrita et S. ocellifer. Les nouvelles espèces se distinguent des autres espèces de Synodontella principalement par la morphologie de leurs organes copulateurs mâles (OCM) : Synodontella speroadotevii a un pénis en deux parties (l'une étant un tube creux et l'autre un tube aplati) ; Synodontella bagoueensis a un large pénis en forme de G avec une ouverture subterminale ; et Sy. akengboi a un pénis simple et étroit en forme de J. Synodontella speroadotevii diffère de Sy. bagoueensis et Sy. akengboi par la forme de la barre transversale dorsale, qui ne montre aucune protubérance, ainsi que dans la morphologie de l'OCM. Synodontella bagoueensis se distingue des deux autres espèces par sa barre transversale dorsale en forme de V et un OCM en forme de G. Synodontella akengboi diffère des deux autres espèces par son OCM en forme de J et par la taille de ses crochets ventraux et dorsaux qui, contrairement aux deux autres espèces, sont presque similaires.

Effects of maternal thiamine deficiencies on the pyramidal and granule cells of the hippocampus of rat pups.

To understand the implication of thiamine deficiency in the neuronal atrophy and cell death we undertook to induce thiamine (B1 vitamine) deficiency during three essential periods of the ontogenesis of rat central nervous system (CNS). Female rats were fed with a thiamine deprived diet during the gestation and lactation, and the fetuses and pups were alternately exposed to prenatal, perinatal or postnatal thiamine deficiencies. On the 45th postnatal day, histological studies were done on the brains of the pups and the structure of the hippocampus was analyzed. The effects of each treatment were assessed by measuring the size and the density of cell nuclei throughout the dentate gyrus and fields CA4, CA3 and CA1 of the hippocampal formation. The hippocampus showed a regional vulnerability in the pups exposed to maternal thiamine deficiencies. It appears that the thiamine deficiency decreased nuclear density (27.20%) more severely than nuclear size (10.56%) in the fetal hippocampus. Consequently, the major part of the teratogenic effects of thiamine deficiency was cellular death, rather than cellular atrophy.