Objectives In Senegal, data on the epidemiology of hepatitis E virus (HEV) are limited, despite the emergence of a human epidemic in 2014. The objective of this study is to assess the prevalence, molecular characteristics, and seroprevalence of HEV in pigs in Senegal. Method Blood samples were collected from pigs immediately after slaughter between September 2018 and December 2019. HEV RNA was detected using real-time reverse transcription polymerase chain reaction, and positive samples were subjected to Sanger sequencing targeting a fragment of approximately 300 bp of the ORF2 gene for molecular characterization. An enzyme immunoassay was performed to assess the seropositivity for anti-HEV antibody. Results Among the 1600 serum samples tested, HEV RNA was detected in 69 serum samples (4.3%). Of these, 13 were successfully sequenced, and phylogenetic analysis showed that all strains belonged to genotype 3. Among 1161 selected RT-qPCR-negative serum tested, 76.6% were positive for anti-HEV antibodies. Conclusion Pigs have been identified as an important reservoir of HEV genotype 3 in Senegal, highlighting the need for integrated “One Health” surveillance to better understand viral circulation and assess the potential risk of zoonotic transmission.

The pest Spodoptera frugiperda, when it invades Africa, is associated with a parasitic fauna, justifying the need to characterize the genetic diversity of its natural enemies in Senegal. Thus the rDNA of the large subunit, 28S was amplified. The study revealed the existence of 12 species of parasitoids obtained and 3 species of entomopathogenic nematodes. Parasitoids are divided into two orders (Hymenoptera and Diptera) and five families (Ichneumonidae, Braconidae, Eulophidae, Encyrtidae and Tachinidae). These parasitoids are Sinophorus exartemae, Chelonus sp., Parapanteles sp., Dolichogenidea sp. 1, Dolichogenidea sp. 2, Meteorus sp., Meteorus orocrambivorus, Euplectrus phthorimaeae, Prochiloneurus testaceus, Ooencyrtus masii, Drino sp. and Senometopia cariniforceps. Nematodes are members of the family Mermithidae and correspond to Hexamermis sp., Mermithidae sp. 1 and Mermithidae sp. 2. All these species attack the larval stage except O. masii which is oophagous. This study also reports new associations between S. frugiperda and the parasitoids S. exartemae, M. orocrambivorus, E. phthorimaeae, P. testaceus, O. masii and S. cariniforceps. To our knowledge, these six species, in addition to Drino sp., have just been known in the entomological fauna of Senegal. Therefore, it is urgent to protect these auxiliaries from the abusive and inappropriate use of chemical insecticides for sustainable management.

ABSTRACT The socio‐economic impact of rearing Gobra zebu cattle in rural areas has yet to be demonstrated in Senegal. This impact was evident in the 1950s when a genetic breeding programme for this breed was initiated by the ‘Centre de Recherches Zootechniques’ of Dahra. The management of animals in this programme has evolved considerably, particularly due to the constraints encountered and the progressive acquisition of knowledge about the animals. This study aims to describe the evolution over time of the weight performance of Gobra zebu cattle reared at the Dahra station. The study utilizes all body weight monitoring data of the animals maintained at the centre from 1952 to 2018. The data were analysed based on age, sex, year of birth and the selection scheme in force at the time of the animal's birth. The average body weights observed in this study are as follows: 23.3 kg at birth, 69.3 kg at 3 months, 106.08 kg at 6 months, 145.9 kg at 1 year, 225.1 kg at 2 years, 294.9 kg at 3 years, 327.06 kg at 4 years and about 350 kg at ages over 4 years. Significant differences in average body weights were noted depending on sex and the selection scheme in place. These results are supported by various research studies conducted at the Dahra station.

Peppers (Capsicum annuum L.) are a market garden crop that contributes to the socio-economic, food and medicinal development of populations. However, nowadays, its production is subject to new environmental challenges, in particular aphid attacks, which have a positive impact on yield. It is therefore necessary to study the effects of these attacks. The general objective of this study is to contribute to the evaluation of the effect of bio-pesticides based on wood ash and Eucalyptus alba on aphids in a pepper crop. To this end, a Fisher block design was adopted. The factor studied was the biopesticide product at three levels (wood ash, Eucalyptus alba and the control) with three replications. The parameters studied were the effect of the two biopesticides, the incidence of aphids, growth, development and yield. The experimental results showed that Eucalyptus alba (T2) had a repellent effect on aphids and was more effective than wood ash (T1). In terms of average weight, production yields were higher with wood ash (T1), which obtained the highest fruit weight (37.00g), followed by E. alba (T2) with an average of (35.70g) and finally the control (T0), which had the lowest average weight (35.05g). Keywords : pepper, aphids, extraction, wood ash, Eucalyptus alba

Papaya leaves (Carica papaya) were tested on eggs and adults of the pest Callosobruchus maculatus. Different formulations based on this plant have been applied to these forms of the pest. The results noted high adult mortality varying depending on the doses, duration of exposure and the formulation applied. The crushing of fresh leaves caused considerable mortality in adults through contact. These are spread over time depending on the doses applied, 55.75% (10g) on the 5th day, 100% for high doses (15g and 20g) from the 10th day. The corrected mortalities induced by this formulation on eggs are very high and proportional to the dose (10g, 15g and 20g gave respectively 93.63%, 97.08% and 100% mortalities). Fumigation of fresh crushed leaves also proved effective on adults with mortalities disproportionate to the dose of between 57.97% and 97.82% around the 3rd and 4th day with the application of all doses. It also gave an embryonic mortality of 94.70% whatever the dose applied. The aqueous extract of the powder of dry leaves of this plant (Carica papaya) showed a variation of the effects over time with the application of different concentrations, the highest mortality 22.93% was recorded with concentration C2 on the 2nd day while C1 and C2 induced respective mortalities of 11.47% and 20.02%. At the egg stage, the aqueous extract induced average mortalities disproportionate to the dose with greater mortality in C2 (72.72%).

Sesame (Sesamum indicum L) is probably the oldest oilseed crop known and used by humans. In the Central African Republic, sesame remains an “orphan crop” due to the lack of scientific data on the genetic diversity of local accessions. Genetic diversity is the extent of genetic variability measured at the level of individuals, a population, a metapopulation, a species or a group of species. It is ensured by the genetic variability between individuals within the species. This study aims to contribute to a better knowledge of the genetic characteristics of sesame accessions in the Central African Republic. Analyses included genome sequence analysis and genetic polymorphism. Total DNA was extracted using the Zymo Research Kit, taking for each accession or variety a pool of five seeds constituting an individual. The results obtained showed the effectiveness of the 28S gene for the differentiation of sesame accessions (Sesamum indicum) because it showed a significant polymorphism between the different accessions studied and the Pakréssaya variety. The phylogenetic trees allowed us to structure sesame seeds according to their locality of origin.

Agriculture in West Africa, particularly in Senegal, plays a crucial role in economic and social development, but it faces numerous challenges, including increasing pressure from pests such as root-knot nematodes. Okra (Abelmoschus esculentus), a highly valued local vegetable, is particularly affected by these nematodes, which cause root gall formation and significantly reduce crop productivity. This study evaluates the effects of different agricultural inputs fermented solution of Calotropis procera, cactus digestate, and chemical fertilizer (NPK) on the germination potential of okra seeds and the formation of root galls caused by Meloidogyne spp. The results show that the fermented solution of Calotropis procera (T1) significantly improves seed germination and completely prevents root gall formation. The cactus digestate (T2) moderately reduces gall formation and promotes germination. In contrast, the chemical fertilizer (T3) and the untreated control (T0) show severe infestation, although plant growth is not directly compromised in the T3 treatment. These findings highlight the potential of organic and bioactive inputs to enhance crop resistance to nematodes while stimulating germination, unlike chemical fertilizers whose long-term effectiveness remains limited

With a view to devising a strategy for protecting groundnut seeds against Caryedon serratus, we tested the biological impact of a product called BioArt made from the leaves of certain plants indigenous to Senegal (Crataeva religiosa, Calotropis procera and Azadirachta indica) and aqueous extracts of Crataeva religiosa on the external forms of C. serratus. The BioArt product caused the greatest mortality in adults. It induced maximum elimination (100%) of adults with the highest dose C1. Extracts of C. religiosa were less effective than BioArt on adults. They induced a maximum effect of 53.33% mortality with the highest dose C1. Females treated with BioArt laid fewer eggs than those treated with aqueous extracts of C. religiosa. With regard to the sex ratio of survivors, a comparative study of the different solutions showed that the BioArt product favoured females, while the C. religiosa extracts were equally distributed between males and females. The ovicidal activity showed almost equal embryonic and larval mortality and a slight difference in pupal mortality (32.41% with BioArt and 47.18% with C. religiosa). Monitoring of surviving eggs showed a lengthening or shortening of the various development times, with larval development, total development and life span being shorter with the BioArt product. The sex ratio was in favour of females for both products.

During this study, we determined different biological parameters of Callosobruchus maculatus populations from two agro-ecological zones of Senegal (the ZSP and the ZVFS). To do this, strains of C. maculatus were collected in two localities, each representing an agro-ecological zone. The analysis of the results obtained shows that fecundity is greater for the strain coming from the silvopastoral zone (55.60 ± 19.144 eggs per female) than for that coming from the Senegal River valley zone (45 ± 18.577 eggs per female.). Furthermore, the evolution of egg laying shows that whatever the strain or population, more than 95% of eggs are laid during the first four days of the infestation with a peak on the second. In addition, the strains are characterized by an egg fertility rate exceeding 65% with a larval survival rate of over 75% and the Fouta strain has the highest rates. However, the emergence rate of the strain from the silvopastoral zone is lower at 49%. The longevity of adults in the Senegal River valley zone is significantly longer (11.035 ± 1.527 days) than that of adults in the silvopastoral zone. The sex ratio is in favor of males for both populations. The total development time and the oviposition-emergence time are relatively the same in the two strains with an average of 31 days and 21 days respectively.