Assessing the Efficacy of Albendazole against Fasciola hepatica in Naturally Infected Cattle by In Vivo and In Vitro Methods

New benzimidazole derivative compounds with in vitro fasciolicidal properties

BACKGROUND

Control of the zoonotic food-borne parasite Fasciola hepatica remains a major challenge in humans and livestock. It is estimated that annual economic losses due to fasciolosis can reach US$3.2 billion in agriculture and livestock. Moreover, the wide distribution of drug-resistant parasite populations and the absence of a vaccine threaten sustainable control, reinforcing the need for novel flukicides.

METHODS

The present work analyses the flukicidal activity of a total of 70 benzimidazole derivatives on different stages of F. hepatica. With the aim to select the most potent ones, and screenings were first performed on eggs at decreasing concentrations ranging from 50 to 5 µM and then on adult worms at 10 µM. Only the most effective compounds were also evaluated using a resistant isolate of the parasite.

RESULTS

After the first screenings at 50 and 10 µM, four hit compounds (BZD31, BZD46, BZD56, and BZD59) were selected and progressed to the next assays. At 5 µM, all hit compounds showed ovicidal activities higher than 71% on the susceptible isolate, but only BZD31 remained considerably active (53%) when they were tested on an albendazol-resistant isolate, even with values superior to the reference drug, albendazole sulfoxide. On the other hand, BZD59 displayed a high motility inhibition when tested on adult worms from an albendazole-resistant isolate after 72 h of incubation.

CONCLUSIONS

BZD31 and BZD59 compounds could be promising candidates for the development of fasciolicidal compounds or as starting point for the new synthesis of structure-related compounds.

Ubenimex combined with Albendazole for the treatment of Echinococcus multilocularis-induced alveolar echinococcosis in mice

Introduction

Alveolar echinococcosis (AE) is a parasitic disease caused by E. multilocularis metacestodes and it is highly prevalent in the northern hemisphere. We have previously found that vaccination with E. multilocularis-Leucine aminopeptidase (EM-LAP) could inhibit the growth and invasion of E. multilocularis in host liver, and Ubenimex, a broad-spectrum inhibitor of LAP, could also inhibit E. multilocularis invasion but had a limited effect on the growth and development of E. multilocularis.

Methods

In this study, the therapeutic effect of Ubenimex combined with Albendazole on AE was evaluated. Mice were intraperitoneally injected with protoscoleces and imaging examination was performed at week 8 and week 16 to detect cyst change. During this period, mice were intraperitoneally injected with Ubenimex and intragastrically administered with Albendazole suspension. At last, the therapeutic effect was evaluated by morphological and pathological examination and liver function.

Results

The results revealed that the combined treatment could inhibit the growth and infiltration of cysts in BALB/c mice infected with E. multilocularis protoscoleces. The weight, number, invasion and fibrosis of cysts were reduced in mice treated with Ubenimex in combination with Albendazole. The same effect was achieved by the single Ubenimex treatment because of its inhibitory effect on LAP activity, but it was less effective in inhibiting the growth of cysts. The levels of ALT, AST, TBIL, DBIL, ALP, and γ-GT were reduced after the combined treatment, indicating that treatment with both Ubenimex and Albendazole could alleviate liver damage.

Discussion

This study suggests that the combined treatment with Ubenimex and Albendazole could be a potential therapeutic strategy for E. multilocularis infections.

The Fasciola hepatica egg development and hatching test (EDHT) using commercial drugs: a simple protocol for tackling anthelminthic resistance and promoting cattle productivity

Fasciolosis is an important zoonotic disease caused by the trematode Fasciola hepatica, and it causes great losses in bovine production. The anthelmintic resistance is a major problem in the control of fasciolosis. In this study, the F. hepatica egg development and hatching test (EDHT) was used for the evaluation of the ovicidal activity of commercial drugs, commonly used for treating infected cattle, which reflects F. hepatica anthelminthic resistance in infected bovines, according to recent literature. Bile samples from F. hepatica naturally parasitized cattle were obtained from slaughterhouses in the cities of Lages and Otacílio Costa, Santa Catarina State, Brazil. The bile was washed, the eggs were recovered, quantified, and distributed in universal collectors, with a minimum of 1,000 eggs per vial. Four commercial drugs were used in this study, containing albendazole sulfoxide (ABDZ), closantel (CSTL), nitroxynil (NTXL), and triclabendazole with fenbendazole (TBZF). The drugs were diluted according to the manufacturer instructions. All drugs, and the respective control, were tested in triplicates, with the quantity of recovered eggs determining the number of drugs to be tested. The vials were incubated for 28 days at 27 °C, and the eggs were classified according to their degree of development under a stereomicroscope. In total, 121 egg samples were analyzed. Two samples were identified as resistant to TBZF. Undetermined resistance/susceptibility has been found in two isolates treated with ABDZ, one treated with NTXL and six treated with TBZF. CSTL did not present ovicidal activity and cannot be used in EDHT. This is the first time that commercial drugs were used in F. hepatica EDHT.

Brief report first report of the in vitro ovicidal activity of camel milk and its fractions on zoonotic-liver fluke (Fasciola gigantica) eggs

Fasciola gigantica is one of the worldwide parasites that cause livestock and human illnesses. Chemotherapy is now the primary therapeutic option for its treatment. Drug abuse has led to the emergence of drug-resistant strains. As a result, there is an urgent need to discover natural and efficient anthelmintics against Fasciola spp. The study aims to evaluate the ovicidal activities of camel milk and its fractions on F. gigantica eggs. In the in vitro assay of F. gigantica eggs were submitted to different concentrations (0.5% and 1%) of camel milk fractions; Camel Milk Whey (CMW), Camel Milk Casein (CMC), and Skimmed Camel Milk (SCM) as well as a positive control (PC) of Nitroxynil (100 mg/ml) and a negative control (NC) with physiological saline. The Egg Hatching Assay (EHA) results showed that camel milk fractions exhibited ovicidal activity, especially CMW, and CMC, which showed 97.58 ± 0.58 and 96.9 ± 1.99 ovicidal activity, respectively, at a concentration of 1% after 15 days of treatment compared to PC, which exhibited 91.75 ± 4.95 ovicidal activity. The egg hatching ratios were 1.67% and 2.33% for CMW and CMC, respectively, compared to 70.17% for the NC and 6% for the PC. The LC50 values for CMW and CMC on the 15th day of treatment were 0.20 and 9.13, respectively. From the results above, we can infer that camel milk and its fractions are promising as a new alternative for fascioliasis control.

Artemisia vulgaris anthelmintic activities to ova and adult stages of Fasciola gigantica in vitro

Background and Aim

Fasciolosis due to Fasciola gigantica is endemic to tropical countries and Fasciola hepatica in temperate climates, highly detrimental to livestock and known as foodborne zoonotic diseases. The strategic control of the disease is mainly the use of chemical anthelmintic. This study aimed to evaluate the anthelmintic properties of Artemisia vulgaris extract on the ova and adult stages of F. gigantica.

Materials and Methods

Samples were collected from the Ampel Abbatoir, Boyolali District, Central Java, Indonesia. The ova from 20-gallbladders of cattle which were naturally infected with F. gigantica and 270 living F. gigantica worms were used in this study. The ovicidal assay was performed by incubating the ova with A. vulgaris in different concentrations, that is, 5%, 2.5%, and 1.25% for 5, 9, 11, 14, and 16 days. The efficacies were evaluated by quantification of ova degeneration during developmental stages in different time points and egg-hatch assay. The flukicidal effects were observed by mortality assay in 5, 10, 20, 40, 80, 160, 320, and 640 min incubations followed by scanning electron microscopy for surface morphology and histology of the fluke's transversal sections.

Results

The concentration of 5% A. vulgaris showed the strongest ovicidal activities. The percentage of hatching ova on day 16 at concentrations of 5%, 2.5%, and 1.25% were 3.33%, 6.67%, and 16.67%. These ova hatch assay showed a significant reduction (p < 0.001) compared to untreated control. The flukicidal effect was significant (p < 0.001) at a concentration of 20%, with a mortality rate reaching 66.67% in the 40 min of incubation time. The surface properties of the adult worms, including the spine, tegument, acetabulum, intestine, and vitelline follicles, were disintegrated.

Conclusion

The results showed that A. vulgaris has the potential ovicidal and flukicidal properties to F. gigantica. The active compounds remained necessary to be elucidated further and its modes of action would be interesting to be predicted by molecular docking modeling.

Microscopic alterations in Fasciola hepatica treated with the essential oils of Pelargonium graveolens and Citrus aurantium

Fasciolosis is one of the most important parasitic diseases in animal health, affecting mainly ruminants, causing economic and productivity losses. This study aimed to evaluate the in vitro ovicidal and adulticidal activity of essential oils (EOs) from Pelargonium graveolens (geranium) and Citrus aurantium (sour orange) on Fasciola hepatica. Performed Gas Chromatography of EOs P. graveolens and C. aurantium, with major compound, citronellol (31.37 %) and limonene (93.89 %), respectively. For the cytotoxicity assay, the sour orange EO showed to be promising when used in lower concentrations. For the ovicidal tests, the eggs were incubated with geranium EOs at concentrations from 4.5 to 0.03375 mg/mL and sour orange at concentrations from 4.25 to 0.031875 mg/mL, along with controls. The viable eggs were counted on the 14th day post-incubation. Adult forms of F. hepatica were incubated containing the EOs and observed for 24 h after treatment, as well as the control groups. Later the specimens were fixed for histological analysis. Geranium and sour orange EOs in trematode eggs at the concentrations tested were 100 % effective in inactivating hatching (p < 0.05) when compared to the untreated control. In the adulticidal test, the essential oil of P. graveolens at both concentrations tested (0.0675 and 0.03375) within 15 h, promoted the death of flukes. For C. aurantium, 18 h was enough to inactivate all specimens, up to a concentration of 0.06375. The histological analysis, observed the accumulation of liquid in the tegument in the specimens incubated in C. aurantium and P. graveolens, with vacuolization in the tegument and spines, preventing externalization. The results of the study present OEs with efficient ovicidal and adulticidal activity.

Tegumental alterations and resistance of Fasciola gigantica adult worms exposed to flukicides in Egypt

Background

The current study was designed to investigate the in vitro effect of commercially available fasciolicides; albendazole (40 and 400 µg/ml), triclabendazole, rafoxanide and nitroxynil (50 and 100 µg/ml, each) against Fasciola gigantica adult worms. For all, worms were incubated for 3 h. Worm's motility was macroscopically and microscopically detected. Reduction of egg deposition was estimated. Alterations of worm's cuticle post-treatments were recorded using scanning electron microscopy (SEM).

Results

Nitroxynil had the most flukicidal effect with mild movement quickly disappeared within 15 min post-treatment. It showed the highest egg reduction (88.3% and 95% at concentrations of 50 and 100 µg/ml, respectively). Findings of SEM showed severe furrowing and destruction of spines. In rafoxanide-treated group, the motility disappeared 75 min post-treatment, and the egg deposition was significantly (P ≤ 0.05) reduced to 70% and 85% at the same concentrations. Teguments showed thickening, moderate furrowing and destruction of the spines. Albendazole showed the lowest effect: the motility of the worms was observed till 160 min post-treatment and the egg reduction was 43% and 75% at the same concentrations. Interestingly, in albendazole-treated flukes, the tegument had severe furrowing and spines were completely sloughed. Similarly, in triclabendazole-treated flukes, worms motility was observed till 160 min post-treatment and the egg reduction was 76.6% and 88.3%. The tegument showed swelling and mild furrowing with moderately damaged spines.

Conclusions

Nitroxynil was the most potent flukicide inducing evidential cuticular changes. Although albendazole induced the most potent cuticular damage, it showed the lowest flukicidal effect. Further in vivo study to investigate resistance/susceptibility of Fasciola species in cattle and buffaloes will be carried out.