Evaluation acaricidal efficacy of botanical extract from Eupatorium adenophorum against the hard tick Haemaphysalis longicornis (Acari: Ixodidae).

The aim of this study was to evaluate the acaricidal activity of a botanical extract from Eupatorium adenophorum against the hard tick Haemaphysalis longicornis. This could result in developing effective extracts of E. adenophorum as a source of natural, low-toxicity plant-based acaricidal drugs. Adult engorged females of H. longicornis were collected from naturally infected goats. The engorged females were reared in the laboratory and their offspring (larvae and nymphs) were used as test ectoparasites. The toxic effects of botanical extracts from E. adenophorum against larvae and nymphs of H. longicornis were evaluated. The results showed that the extracts with 1.5 and 1.0g/ml (w/v) concentrations were toxic for H. longicornis, comparable to a toxic effect of 2% chlorpyrifos (positive control). The median lethal time (LT50) for larval and nymphal ticks with 1.5g/ml (w/v) concentration of extract were 0.790 (LT99=1.065) and 1.018 (LT99=10.608) hours, respectively, whereas the LT50 of 1.0g/ml (w/v) concentration were 1.445 (LT99=6.047) and 1.313 (LT99=29.932) hours for larval and nymphal ticks, respectively. At a concentration of 1.5g/ml (w/v), an acaricidal effect of 100% was achieved for both larval and nymphal ticks, while a concentration of 1.0g/ml (w/v) resulted in 100% (for larvae) and 93% (for nymphs) within a 6h period. In additional, we found that the relatively low concentration (0.5g/ml) also obtained a good acaricidal effect during the short experimental period, with 2.22 and 2.651h LT50 for larval and nymphal ticks, respectively. These results indicate that E. adenophorum contains potent acaricidal ingredients against the hard tick H. longicornis.

Clinical efficacy of botanical extracts from Eupatorium adenophorum against the Sarcoptes scabiei (Sarcoptidae: Sarcoptes) in rabbits.

The aims of present study were to evaluate the therapeutic efficacy of extracts from Eupatorium adenophorum against Sarcoptes scabiei. A 30-day experiment was performed using New Zealand rabbits that were naturally infested with S. scabiei in the toes (n=30) or artificially infected in the external ear margin with S. scabiei (n=30). Rabbits were randomly divided into five groups (6 animals per group, A-E groups for rabbits of naturally infested and F-J groups for artificially infected rabbits), respectively. All 60 rabbits were treated twice on days 0 and 7 successively. Animals in groups A/F, B/G, and C/H were treated on each toe/external ear margin with topical E. adenophorum ethanol extract at 1.0, 0.5 and 0.25 g/ml (w/v), respectively. Animals in groups D/I and E/J were treated with ivermectin by injections (positive controls) or by glycerol with water only rubbed onto the affected area (negative controls). After two treatments with extracts of E. adenophorum with relatively high concentrations of 0.5 and 1g/ml, the S. scabiei was completely eliminated in rabbits between days 14 and 30. Our results showed that rabbits treated with ivermectin (positive controls) and those treated with the extracts of concentrations of 1.0 or 0.5 g/ml achieved remarkable therapeutic efficacy; no mites were present in toes of rabbits in these groups on day 14, which confirmed a 100% therapeutic efficacy rate up to day 30 of the end of the trial. The clinical effects of treatment with 1.0 and 0.5 g/ml E. adenophorum extracts (groups A and B) were similar to ivermectin treatment. However, the therapeutic efficacy in group C and E rabbits only reached 43.25% and 7.13% by day 14. Furthermore, the therapeutic efficacy improved slightly by the end of the experiment on day 30, and rabbits in groups F, G and I also achieved good efficacy according to the recovery scoring criteria. These results indicate that E. adenophorum contains potent compounds for the effective control of sarcoptidosis.

Clinical efficacy of botanical extracts from Eupatorium adenophorum against the scab mite, Psoroptes cuniculi.

This study evaluated the in vivo clinical efficacy of Crofton weed (Eupatorium adenophorum) extracts against the scab mite, Psoroptes cuniculi. A 30-day experiment was performed using New Zealand rabbits that were naturally infested with P. cuniculi on a farm. Rabbits were randomly divided into five groups (6 animals per group); animals in groups A, B and C were treated in each ear topically with 2 ml of 1.0, 0.5 and 0.25 g/ml (w/v) E. adenophorum ethanol extract, respectively. Animals in groups D and E were treated with ivermectin (by injection; positive controls) and glycerol with water only (by embrocation; negative controls), respectively. Each rabbit was treated twice with separate treatments on days 0 and 7. Rabbits were observed daily and detailed examinations were performed on days 0, 7, 14 and 30, to inspect the presence or absence of mites and scabs/crusts. Clinical infection and the degree of recovery were evaluated, and the rate of reduction in mites and clinical efficacy rate (%) were calculated. The clinical effect of treatment with E. adenophorum extracts was similar to treatment with ivermectin. Seven days after the initial treatment, the mean clinical scores (presence of scabs/crusts) decreased from 3.32, 3.08 and 3.17 to 0.37, 0.47 and 0.48 in the left ears of animals in groups A, B and C, respectively, and from 3.53, 3.73 and 3.67 to 0.40, 0.45 and 0.48 in the right ears of animals in groups A, B and C, respectively, which were similar to the observations recorded in the positive control rabbits. However, the clinical score for negative control rabbits did not decrease significantly (P>0.05) during the experiment, and this changed from 3.32 to 2.75 in the left ears and from 3.50 to 3.25 in the right ears, and there were no significant differences in clinical efficacy between left and right ears. After two treatments (7 days space), the rabbits in groups A, B, C and D had recovered completely 30 days after the last treatment and no recurrences of infection were observed. These results indicate that E. adenophorum contains potent compounds for the effective control of animal acariasis.

Genetic variability of Echinococcus granulosus from the Tibetan plateau inferred by mitochondrial DNA sequences.

To analyse genetic variability and population structure, 84 isolates of Echinococcus granulosus (Cestoda: Taeniidae) collected from various host species at different sites of the Tibetan plateau in China were sequenced for the whole mitochondrial nad1 (894 bp) and atp6 (513 bp) genes. The vast majority were classified as G1 genotype (n=82), and two samples from human patients in Sichuan province were identified as G3 genotype. Based on the concatenated sequences of nad1+atp6, 28 different haplotypes (NA1-NA28) were identified. A parsimonious network of the concatenated sequence haplotypes showed star-like features in the overall population, with NA1 as the major haplotype in the population networks. By AMOVA it was shown that variation of E. granulosus within the overall population was the main pattern of the total genetic variability. Neutrality indexes of the concatenated sequence (nad1+atp6) were computed by Tajima's D and Fu's Fs tests and showed high negative values for E. granulosus, indicating significant deviations from neutrality. FST and Nm values suggested that the populations were not genetically differentiated.

Acaricidal activity of extract from Eupatorium adenophorum against the Psoroptes cuniculi and Sarcoptes scabiei in vitro.

The possible acaricidal activity of Eupatorium adenophorum was analyzed using extracts created by water decocting, ethanol thermal circumfluence, and steam distillation. The toxic effect of each extract was tested against Psoroptes cuniculi and Sarcoptes scabiei in vitro. Ethanol thermal circumfluence extract had strong toxicity against mites, killing all S. scabiei at 0.5 and 1.0 g/ml (w/v) concentration, while 1g/ml extract was also found to kill all P. cuniculi within a 4-h period. Similarly, 0.25, 0.5 and 1.0 g/ml concentration of extract had strong toxicity against S. scabiei, with median lethal time (LT(50)) values at 0.866, 0.785 and 0.517 h, respectively. 0.5 g/ml and 1g/ml showed strong acaricidal action against P. cuniculi; the LT(50) values were 0.93 h and 1.29 h, respectively. The median lethal concentration (LC(50)) values were 0.22 g/ml for Scabies mite and 0.64 g/ml for P. cuniculi in 1h. The results indicated that E. adenophorum contains potent acaricidal ingredients; as a first step in the potential development of novel drugs, it may provide new acaricidal compounds for the effective control of animal acariasis.