Hafidh Akkari

In vitro evidence that the pastoral Artemisia campestris species exerts an anthelmintic effect on Haemonchus contortus from sheep

Occurrence of anthelmintic resistant strains of helminths is increasing. The aim of this study was to evaluate the in vitro anthelmintic activity of Artemisia campestris in comparison to albendazole against Haemonchus contortus of sheep. In this respect, in vitro anthelmintic activities of crude aqueous and crude ethanolic extracts of aerial parts of A. campestris were investigated on eggs and adults of Haemonchus contortus. Chemical analyses revealed that overall profile of both extracts samples were dominated by flavonoids among them quercetin and apigenin derivatives were the most abundant phenolics constituents. Both extract types completely inhibited egg hatching at a concentration close to 2 mg/ml. Lethal concentration 50% of A. campestris ethanolic and aqueous extracts were 0.83 and 1.00 mg/ml respectively (p < 0.05). The ethanolic extract showed better in vitro activity against adult parasites than the aqueous extract in terms of the paralysis and/or death of the worms at different hours post-treatment. Dose dependent activity was also observed for both extract. After 8 and 24 h of exposure, the ethanolic extract induced 91.3 and 100% mortality at the highest tested concentration respectively, while the aqueous extract induced 3.22 and 70.96% at the same concentration respectively.To our knowledge, these results depict for the first time that A. campestris possesses in vitro anti-Haemonchus contortus properties.

Epidemiological study of sympatric Haemonchus species and genetic characterization of Haemonchus contortus in domestic ruminants in Tunisia.

Parasitic gastroenteritis caused by Haemonchus spp. is a major cause of economic losses in the livestock industry, especially in tropical and subtropical areas. The correct identification of various species, as well as knowledge regarding the epidemiology and genetic characterization of the principal circulating species, is essential for the establishment of sustainable control strategies. A study was carried out to determine the prevalence of Haemonchus species in sheep, goats and cattle slaughtered in Béja abattoir from January to June 2010 and also to analyse the genetic differences of Haemonchus contortus in these ruminants. During the study period 364, 271 and 152 abomasa of sheep, goats and cattle respectively, were examined showing overall prevalence rates of 17%, 33.6% and 7.23%, respectively. In addition, spicules morphometric study of 300 male worms randomly collected from sheep showed the presence of 239 (79.66%) H. contortus and 61 (20.33%) H. placei. Likewise, out of 508 adult male Haemonchus from goats, 325 (63.97%) H. contortus and 183 (36.02%) H. placei worms were identified. Whereas for cattle, out of 84 adult male Haemonchus, 52 (61.9%) H. contortus and 32 (38.09%) H. placei worms were identified. The study showed the association of H. contortus and H. placei as a predominant type of infection in all hosts, co-infection concerned 62.5% of sheep, 54.71% of goats and 37.5% of cattle. Using the polymerase chain reaction, the second Internal Transcribed Spacer region (ITS-2) of the nuclear ribosomal DNA (rDNA) of H. contortus was amplified and sequenced. A total of 16 ITS-2 sequences were identified (five from sheep, three from cattle and eight from goats). The 231 base pairs of different ITS-2 sequences were aligned and analysed. Distance based analysis using Neighbour-Joining method and parsimony analysis were used to construct phylogenetic trees to elucidate genetic relationships. The analyses categorized the ITS-2 sequence of H. contortus into four groups. Groups 1 and 4 were found exclusively in goats, whereas groups 2 and 3 were found in sheep and cattle. This study demonstrates variability in nucleotide sequence within the ITS-2 region that reveals genetic diversity among populations of H. contortus, including those from different domestic ruminant species in Tunisia. To our knowledge, this is the first work in North Africa describing the genetic diversity of H. contortus in domestic ruminants.

Amoebicidal activity of α-bisabolol, the main sesquiterpene in chamomile (Matricaria recutita L.) essential oil against the trophozoite stage of Acanthamoeba castellani Neff

Acanthamoeba genus includes opportunistic pathogens which are distributed worldwide and are causative agents of a fatal encephalitis and severe keratitis in humans and other animals. Until present there are not fully effective therapeutic agents against this pathogen and thus the need to search for novel anti-amoebic compounds is urgent. Recently, essential oils of aromatic and medicinal plants have shown activity against Acanthamoeba strains. Therefore, this study was aimed to evaluate the activity of main component of chamomile essential oil (a sesquiterpene) namely α-bisabolol against the Acanthamoeba castellani Neff strain. After evaluation of the activity and toxicity of this molecule, IC50 values of 20.839 ± 2.015 for treated amoebae as well as low citotoxicty levels in a murine macrophage cell line was observed. Moreover, in order to elucidate mechanism of action of this molecule, changes in chromatin condensation levels, permeability of the plasmatic membrane, the mitochondrial membrane potential and the ATP levels in the treated amoebic strains were checked. The obtained results revealed that α-bisabolol was able to induce apoptosis, increase the permeability of the plasmatic membrane and decrease both mitochondrial and ATP levels in the treated amoebae. Therefore, and given the obtained results, α-bisabolol could be used a future therapeutic agent against Acanthamoeba infections.

Non-cytotoxic Thymus capitata extracts prevent Bovine herpesvirus-1 infection in cell cultures.

BackgroundBovine herpes virus type 1 (BHV-1) still causes great economic loss to the livestock industry and trade because there aren’t any available drugs that proved to be fully effective against it. In this study, the cytotoxicity and the antiviral activities of the Thymus capitata extracts were evaluated for the development of new, non toxic and specific anti-herpesvirus drug. Aqueous extracts (AE), ethanolic extracts (EE) and essential oil (EO) of the aerial parts of Thymus capitata were analyzed to determine their chemical compositions by gas chromatography, and high performance liquid chromatography combined with mass spectrometry. Their cytotoxicity and antiviral activities against Bovine Herpesvirus type 1 (BHV-1) were evaluated by quantifying the reduction of the viral cytopathic effect using Madin-Darby Bovine Kidney cell line with colorimetric assay. T. capitata extracts were added at different stages of the viral infection to investigate and better quantify their potential inhibitory effects.ResultsPolyphenols and flavonoids were the major compounds found in T. capitata EO, EE and AE. The cytotoxic concentrations at 50% were 48.70, 189 and 289 μg ml−1 for EO, EE and AE, respectively. The inhibitor concentrations at 50% for the EO, EE and AE, were 3.36, 47.80 and 164 μg ml−1, respectively. The selectivity index anti-BHV-1 values were 14.49, 3.95 and 1.81 for EO, EE and AE, respectively. Thus, the EO extracts were the most efficient antiviral compounds. T. capitata extracts affect mainly the adsorption of BHV-1 virus to host cells.ConclusionT. capitata extracts inhibit the viral replication by interfering with the early stages of viral adsorption and replication. Thus, T. capitata is a potential candidate for anti-herpesvirus treatment.

Dynamics of infestation of tracers lambs by gastrointestinal helminths under a traditional management system in the North of Tunisia

The authors present a survey of gastrointestinal helminths of sheep on permanent pastures in the extreme north region of Tunisia (Mediterranean climate). Dynamic infestation of animals has been monitored by using batches of three tracer lambs introduced each two months during 2004 and 2005. These lambs were kept in the pens of veterinary school of Sidi Thabet (Tunisia) during three months and then necropsied. Faecal and blood samples were took from tracer lambs each two months during the whole period, and from animal flock only during 2004. The main helminth genera encountered were Trichostrongylus spp., Teladorsagia spp., Strongyloides papillosus and Anoplocephalidea; occasionaly were found Nematodirus, Oesophagostomum, Chabertia, Cooperia, Trichuris and Paramphistomum. The egg count of the ewes and lambs in the flock showed two peaks. For both ewes and lambs there is a gradual increase from January with a peak in May-June. This first peak is considered to be due to acquisition of infective larvae during the rainy and cold season, as evident from the worm burdens of tracer lambs. The second peak was exclusively observed in ewes during late autumn-early winter (November-December); it has two origins: infestation by third larvae stage and the periparturient rise. The worm burdens of tracer lambs showed that there was a gradual accumulation of nematodes from September- October, reaching a peak in March-April; a very low or naught infection is reported during the dry period (July-August). Infection by Anoplocephalidea was higher during the dry season. This study is primordial for a comprehensive control programme implementation against gastrointestinal helminths.

Chemical analyses and anthelmintic effects of Artemisia campestris essential oil

The present study aimed at analyzing the chemical composition and evaluating the in vitro and in vivo anthelmintic activity of Artemisia campestris essential oil aerial parts. The chemical composition was analysed by gaz chromatography/mass chromatography (GC/MS). Fifty compounds were identified representing 99.98% of the total oil. A. campestris essential oil was dominated by beta-pinene (36.40%) and 2-undecanone (14.7%). The in vitro anthelmintic activity tests of A. campestris essential oil were performed on Haemonchus contortus using egg hatch assay (EHA) and adult worms motility assay (AWMA) compared with a reference drug albendazole. In the EHA 100% inhibition was observed at 2 mg/ml after 48 h incubation (IC50 = 0.93 mg/ml). In the AWMA, essential oil induced 66.6% inhibition at 0.5 mg/ml after 8 h post exposure. The nematicidal effect of essential oil was evaluated on Heligmosomoides polygyrus. It was monitored through faecal egg count reduction (FECR) and total worm count reduction (TWCR). Three doses (2000, 4000 and 5000 mg/kg) were studied using a bioassay. The dose of 5000 mg/kg showed a high nematicidal activity (72.1% FECR and 72% TWCR), 7 days post-treatment. The results of the present study suggest that A. campestris essential oil has a potential anthelmintic activity and further studies are required in order to establish its mechanisms of action.