Co-Administration of Adjuvanted Recombinant Ov-103 and Ov-RAL-2 Vaccines Confer Protection against Natural Challenge in A Bovine Onchocerca ochengi Infection Model of Human Onchocerciasis

Onchocerciasis (river blindness), caused by the filarial nematode Onchocerca volvulus, is a neglected tropical disease mainly of sub-Saharan Africa. Worldwide, an estimated 20.9 million individuals live with infection and a further 205 million are at risk of disease. Current control methods rely on mass drug administration of ivermectin to kill microfilariae and inhibit female worm fecundity. The identification and development of efficacious vaccines as complementary preventive tools to support ongoing elimination efforts are therefore an important objective of onchocerciasis research. We evaluated the protective effects of co-administering leading O. volvulus-derived recombinant vaccine candidates (Ov-103 and Ov-RAL-2) with subsequent natural exposure to the closely related cattle parasite Onchocerca ochengi. Over a 24-month exposure period, vaccinated calves (n = 11) were shown to acquire infection and microfilaridermia at a significantly lower rate compared to unvaccinated control animals (n = 10). Furthermore, adult female worm burdens were negatively correlated with anti-Ov-103 and Ov-RAL-2 IgG1 and IgG2 responses. Peptide arrays identified several Ov-103 and Ov-RAL-2-specific epitopes homologous to those identified as human B-cell and helper T-cell epitope candidates and by naturally-infected human subjects in previous studies. Overall, this study demonstrates co-administration of Ov-103 and Ov-RAL-2 with Montanide™ ISA 206 VG is highly immunogenic in cattle, conferring partial protection against natural challenge with O. ochengi. The strong, antigen-specific IgG1 and IgG2 responses associated with vaccine-induced protection are highly suggestive of a mixed Th1/Th2 associated antibody responses. Collectively, this evidence suggests vaccine formulations for human onchocerciasis should aim to elicit similarly balanced Th1/Th2 immune responses.</jats:p

In vitro nematocidal potential of hydro-ethanolic and aqueous extracts of Calotropis procera (Aiton) W.T. Aiton, 1811 (Apocynaceae) and Faidherbia albida (Delile) A. Chev., 1934 (Fabacae) against Onchocerca ochengi and Caenorhabditis elegans

Onchocerciasis caused by Onchocerca volvulus Leuckart, 1893 is the second-world infection responsible for human blindness. Except Ivermectin which has as targets the microfilariae of that parasite, specific treatment for this disease does not exist and in developing countries, medicinal plants seem to remedy that health problem. For that, aqueous and hydro-ethanolic leaf, bark, and root extracts of Calotropis procera and Faidherbia albida were evaluated in vitro, against the most popular bovine model, Onchocerca ochengi and the free-resistant nematode Caenorhabditis elegans. O. ochengi microfilariae and adults extracted from the bovine nodules and skins as well as the free strains of C. elegans were exposed to the various concentrations of the plant parts extracts and Ivermectin. In results, all the plant parts extracts were rich in tannins, saponins, alkaloids, flavonoids, phenols, coumarins, and glycosides. Phenols (175.45 ± 0.01 mg EGA/g DM), flavonoids (158.98 ± 0.05 mg EC/g DM), and tannins (89.98 ± 2.56 mg ETA/g DM) contents were high in the bark hydro-ethanolic extract of F. albida. The leaf hydro-ethanolic extract of F. albida induced high activity against O. ochengi microfilariae (CL50 = 0.13 mg/mL). The bark hydro-ethanolic extract of F. albida was also the most effective on O. ochengi adults and particularly on female adults (CL50 = 0.18 mg/mL). Against the parasite strain resistant to Ivermectin, F. albida leaf hydro-ethanolic extract appeared more active with CL50 = 0.13 mg/mL. Similarly, the bark hydro-ethanolic extract of F. albida was the most potent on the wild strain of C. elegans. Thus, this study validates the use of these plants by traditional healers in the management of onchocerciasis and suggests a new source of isolation of the potential plant compounds against Onchocerca

Evaluation Of Smoked Fish Market Trends In The City Of Ngaoundere (Adamawa-Cameroon)

This study was conducted to evaluate the market trends of smoked fish in the city of Ngaoundere (Adamawa-Cameroon). A questionnaire survey was conducted among 37 smoked fish retailers in 2 subdivisions of Ngaoundere. The data collected were analysed and processed using Excel software 2016. The results showed that in the Ngaoundere I and II subdivisions, consumers of smoked fish experience scarcity during certain periods of the year and this is related to the biological cycle of the fish. Also, smoked fish is sold mainly by men (89.19%), young people aged between 20 and 40 years (83.79%). The ethnic group most represented in the sector is Mousgoum (72.97%). The main source of supply for retailers is Lagdo (54.05%). Only 10.81% of retailers obtain their supplies locally, so that 89.19% of fish sold in Ngaoundere town comes from elsewhere (Lagdo, Tibati, Lom pangar, Maga, etc.). Tilapia is the most popular species (51.35%) because of its organoleptic properties and accessibility. The average daily income of a trader is less than 15,000 FCFA (56.76%). Smoked fish is subject to attacks by pests, which are mainly insect pests (76%). The most common means of combating pests are heating with wood fires (48.65%) and the use of insecticides (24.32%). Retailers (100%) face several institutional, financial, economic and commercial constraints in carrying out their activity which if adequately addressed can help better organise the sector for the protection of stakeholders

Technico-Economical Diagnosis of Traditional Goats Farms Based on Zootechnical Performances in the Locality of Wakwa (Adamawa Region-Cameroon)

A survey was carried out in the locality of Wakwa, region of Adamawa-Cameroon during the month of April 2021. The purpose of this study was to determine the elements of calculation of the gross product, intermediate consumption, and the method of calculation of the added value of traditional farms in the area with the zootechnical parameters of the goat as elements of economic production through the administration of a previously established questionnaire. The questions asked concerned: the socio-economic profile of the breeders, the farming or breeding system practiced the zootechnical parameters and the price and cost elements of inputs. It was noticed from this survey that the gender profile of the farmers is made up mostly of men (80%), most of who were above twenty years (92%), with agriculture (56%) as principal activity, trade (20%), handicrafts, pottery, sewing and other side activities (24%). They were mostly persons having received no formal education (68%). Regarding zootechnical parameters, the size of the herd did not exceed 10 animals for the majority of farms (76%). The selling price of the animals varied between 15,000 FCFA and 60,000 FCFA. The Litter of birth goat obeyed the principle of twinning with less than two litters per year or five cubs for a goat. The mortality of neonates and kids was less than 30%, which brings the number of adult goats to between 3 and 4 per year. Grosso modo, the goat breeding activity provides breeders with an estimated annual income of around 64,251.709 CFA, with a total cost of intermediate consumption over the mother's career of 7,904.9922 FCFA for a Gross Added Value of a mother over the duration of her career estimated at 143,300.698 FCFA