In vitro Efficacy of Albendazole against Strongyle eggs recovered from Trade Goats slaughtered at the Nsukka Abattoir: A Preliminary Survey of Resistance to Albendazole

The efficacy of Albendazole against trichostrongyle nematode parasites in goats presented for slaughter at the Nsukka municipal abattoir was evaluated using the In vitro Egg hatch assay (EHA) model. The abattoir was visited once every week for 4 consecutive months during which a total of 240 goats were sampled. Fecal samples were collected per rectum from a minimum of 15 goats on each day of the visit. Egg Hatch Assay was performed on strongyle eggs recovered from pooled faecal sample on each day of sampling with a 2.5% W/V Albendazole. Faecal culture was also set up from the pooled faecal sample on each sampling day to recover and identify the nematode parasites present in the goats. Among the 240 goats sampled, the prevalence of trichostrongylosis as observed by the presence of strongyle eggs was 94.6% (227/240). Faecal culture and larval identification revealed 69.8% of the strongyles as Haemonchus contortus, while 25.5 and 4.8% were Trichostrongylus colubriformis and Oesophagostomum species respectively. In the EHA, Albendazole had mean LC50 value of 0.16 µg/ml which is slightly in excess of the discriminating dose of 0.1µg/ml as prescribed by the World Association for the Advancement of Veterinary Parasitology (WAAVP) as an indication of anthelmintic resistance. There is therefore an urgent need to screen the nematode parasite population in the Nigeria for the presence Albendazole resistance genes. Key words: GI nematode; egg hatch assay; goat; Albendazole; Resistance; Nigeria

Essential oil of Rosmarinus officinalis induces in vitro anthelmintic and anticoccidial effects against Haemonchus contortus and Eimeria spp. in small ruminants

This work aimed to evaluate the valorisation of the volatile oil of “Rosmarinus officinalis L.”, a spontaneously growing medicinal plant in Tunisia, by studying its chemical composition, anthelmintic and anticoccidial potentials against Eimeria spp. and Haemonchus contortus at different essential oil concentrations. The main compounds of the R. officinalis essential oil identified by GC/MS were three monoterpenes: 1,8-cineole (52.06%), α-pinene (15.35%) and camphor (7.69%). The anticoccidial activity was estimated by the inhibition percentage of the oocyte sporulation in addition to the unsporulated and degenerated Eimeria oocysts using a haemocytometer after exposure to different essential oil concentrations. The essential oil was active against Eimeria spp. oocysts of sheep at IC₅₀ = 1.82 ug/ml. Therefore, the IC₅₀ values of the anticoccidial activity of this oil examined was 1.82 mg/ml. The anthelmintic efficacy of the rosemary volatile oil against Haemonchus contortus was realised by two in vitro tests: the egg hatch assay (EHA) and the adult worm’s motility assay (AWMA), by comparing this efficacy with albendazole (anthelmintic, of reference). In the egg hatch assay, the percentage of inhibition was observed at 16 mg/ml and was 73.76% after 2 days of incubation (IC₅₀ = 11.41 mg/ml) and for the adult worm’s motility assay, it was 100% inhibition.

In Vitro Pharmacodynamics of Benzimidazole and Tetrahydropyrimidine Derivatives in European Bison Gastro-Intestinal Nematodes

The present study was aimed to evaluate the efficacy of anthelmintic agents against intestinal nematodes found in European bison. It was performed between October 2016 and May 2017, using Egg Hatch Assay (EHA) and Larval Development Assay (LDA). The parasites were obtained from faecal samples, harvested from bisons in Romania and Sweden. The efficacy of albendazole (ABZ), mebendazole (MBZ) thiabendazole (TBZ) and pyrantel (PYR) was tested. In EHA, the maximum efficacy was observed in MBZ (EC50 = - 0.227 μg/ml), and then TBZ (EC50 = - 0.2228). ABZ had a weaker result, EC50 being 0.326 μg/ml. All tested benzimidazoles registered hatching percentages below 50%, reflecting the lack of parasitic resistance. MIC obtained in the LDA tests were 0.2144 μg/ml for TBZ, 0.2792 μg/ml for PYR, 0.5429 μg/ml for MBZ, while ABZ came last (MIC = 0.8187 μg/ml). The in vitro tests proved the antiparasitic molecules efficacy against bisons nematode population and a limited risk of inducing resistance phenomena.

Effect of Various Acaricides on Hatchability of Eggs ofRhipicephalus (Boophilus) microplus

The effect of commonly used acaricides (amitraz, cypermethrin, deltamethrin, fenvalerate, and flumethrin) on the eggs ofRhipicephalus (Boophilus) micropluscollected from Ludhiana, Punjab, was evaluated by egg hatch assay (EHA). The regression graph of probit hatchability and per cent inhibition of hatching (IH%) of eggs was plotted against log values of concentration of various acaricides. All concentrations of flumethrin and amitraz caused complete inhibition of hatching, whereas a hatchability of31.0±6.1,40.0±5.2and19.3±1.7% was only recorded at the highest concentration of cypermethrin, deltamethrin, and fenvalerate, respectively. An increase in the concentration of the acaricide showed a significant effect on the IH% of eggs for cypermethrinP<0.01and deltamethrinP<0.05but was nonsignificant for fenvalerate. The slope of the regression curve of IH% was utilized for the calculation of the dose of various acaricides causing inhibition of hatching for 95% eggs (LC95) and the discriminating dose (DD). Results indicated that maximum DD was recorded for fenvalerate (2.136%), followed by cypermethrin (0.214%) and deltamethrin (0.118%). The results of the current study will be helpful in formulating effective control strategies against ticks.