Metacercariae Of Fasciola Gigantica Research Articles

Evaluate therapeutic efficacy of Triclabendazole and Mirazid in Guinea Pigs infected with Fasciola gigantica

Aim and Background: Fascioliasis is the most important parasitic diseases that affect the human and animal all over the world. Triclabendazole (TCBZ), and Mirazid is the most common trematodicidal drug used in Egypt The present study, aimed to evaluate the therapeutic efficacy of the TCBZ and Mirazid in Guinea pigs experimentally infected with Fasciola gigantica Methods: Thirty two, Guinea pig (1-2 month old) was allocated into four equal groups to study the efficacy of treatment of facioliasis with triclabendazole (TCBZ) and mirazid. Group (Gp.1) was the control, GPs (2 -4) were orally inoculated with 20 Fasciola giganticametacercariae (FGM) for each as a single dose by using stomach tube. Gps (3&4) were treated orally, with TCBZ, as a single dose (36 mg/Kg Bw) and mirazid 200 mg/ Kg Bw for six successive days respectively. The drugs were administered in the 8th week post-infection to evaluate their efficacy against adult stages of Fasciola gigantica. Blood samples were collected at the end of the 1st and 2nd week post treatment for hematological and serum biochemical examination. Results:TCBZ treated groups (GP 3) showed macrocytic hypochromic anemia, which disappeared at the end of the 2nd week post treatment. Heterophilia, esinophilia and lymphopenia were encountered in non treated group (GP 2) and mirazid treated group (GP 4). The liver transaminase (ALT, AST), gamma glytamyl transferase (GGT) and alkaline phosphatase (ALP) as well as total bilirubin, urea and creatinine, were elevated while serum albumin was decreased in GP (2) and returned to the normal value in GP (3) and GP (4) after two weeks post-treatment. Conclusion:It could be concluded that; the triclabendazole is more effective than mirazid in the treatment of Fasciola giganticainfection. Further research should be done for more precise knowledge about the efficacy of mirazid as a fasciolicidal drug.

The pathology observed in experimental <i>Fasciola gigantica</i> infected Yankasa sheep in Zaria Nigeria.

A study was conducted to determine the pathogenic effects of Fasciola gigantica infection on Yankasa sheep for a period of four months (April-July ,2010). Pathological lesions were observed in four Fasciola gigantica infected Yankasa sheep that died at the 10th, 11th and 12th week post-infection in an experimental infection at the Reproduction unit of the National Animal production Research institute, Shika-Zaria, Nigeria. The experiment involved twelve Yankasa sheep that were divided into two groups of infected and controls. The six animals in the infected group were each orally inoculated with 1200 Fasciola gigantica metacercariae and monitored for a period of 16 weeks. The pathogenic effects of the Fasciola gigantica infection began to manifest through death of four sheep among the infected group; with one death observed on the 10th week, two on the 11th and one on the 12th week post-infections respectively. The gross pathological lesions observed were hepatomegally, appearance of migratory tracts on the liver surface, appearance of puncture wounds through which protruded the anterior ends of the flukes to the liver surface as well as a fluid filled cavity with each having a fluid content of not less than 2.5 litres within the abdominal cavity. Other features observed grossly were marked distension of the gall bladder in which numerous flukes were present. The histopathological lesions were presented inform of intense hemorrhage both in the parenchyma and in the parasite tracts. There was fibrosis and distortion of the normal architecture of the hepatic cells. Observed clinical signs were inappetance, progressive anaemia and emaciation. There was a marked reduction in albumin and total plasma protein levels in the blood of the infected sheep compared to their controls. The findings of this study revealed that Fasciola gigantica is highly pathogenic to Yankasa sheep, therefore strategic control of the parasite and its intermediate host in the study area is recommended for improved sheep production.Keywords: Yankasa sheep, Liver, lesion

Haematological responses of yankasa sheep to experimental Fasciola gigantica infection in Zaria, Nigeria

Haematological responses of Yankasa sheep to experimental Fasciola gigantica infection were evaluated using twelve Yankasa ewes aged 10-12 months. The animals were obtained from the Reproduction Unit of the National Animal Production Research Institute, Shika-Zaria, Nigeria. 2weeks baseline pre-infection data were collected and the ewes were later divided into two groups of infected and controls respectively. The six animals in the infected group were each orally inoculated with 1200 Fasciola gigantica metacercariae and monitored for a period of 16weeks. Mean packed cell Volume (PVC), haemoglobin concentration and total plasma protein of the infected group were significantly lower than the controls (p<0.01). Eosinophilia featured in the infected sheep. Mean White Blood Cell (WBC), neutrophil and lymphocyte levels of the infected sheep were significantly (p<0.05) different from those of the controls at the advanced periods of the infection (12-14weeks pI) in this study. Fasciola gigantica eggs were seen in faeces at 12 th week post infection demonstrating a high mean egg per gram (E.P.G) count of 530 ± 96.44. The findings of this study revealed the potentials of haematological parameters as a veritable diagnostic tool in the management of ovine Fasciolosis.

Evaluation of Fasciola gigantica infection by serial enzyme patterns

Three calves were infected with 2000, 3000 and 4000 metacercariae of Fasciola gigantica . Two other calves were left as uninfected controls. All calves were kept indoor for 23 weeks. During this period, serial samples of plasma and faeces as well as body weight gains were taken. Eggs were first detected in the faeces of infected calves on week 13 post infection (PIW13). In the infected animals, AST activity rose from an average level of 57.5 units/ml to 71 units/ml whereas GGT rose from an average level of 7.8IU/l to 65.6 IU/l. The percentage increase in body weightS of all calves were comparable during the first nine weeks after infection. Between PIW 9 and 13, the infected animals gained weight between 0.6% and 0.7% of their initial body weights. The percentage increase in body weights of the controls during the same period was between 11% and 17%. It was concluded that serial plasma enzyme patterns are useful in evaluating the different stages of F. gigantica infections.

Serum enzyme and hematological profile of Fasciola gigantica immunized and experimentally infected riverine buffaloes

Sixteen male, yearling Murrah buffaloes were randomly assigned to four groups of four buffaloes each. Each animal in Gr-I and II were immunized, respectively, with 4.8 mg of excretory secretory antigen and 1,300 microg Infection Specific Antigen, in three divided doses. Subsequently, each animal in Gr-I, II, and III was per os infected with 800 viable Fasciola gigantica metacercariae (bubaline origin) on week-6 after the start of the experiment, while animals in Gr-IV served as healthy controls. The aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations progressively increased during the prepatency and respectively attained the highest levels during week-6 and 8 post-infection (PI). The alkaline phosphatase (AP) exhibited elevated trends from eighth week PI onward and continued to be higher until the end (p < 0.05-0.01). With the cessation of traumatic activities of the diastomes, the AST and ALT levels declined yet were throughout significantly higher than the healthy controls (p < 0.05-0.01). In the immunized animals (Gr-I and II), the fluctuation patterns were similar but the values were significantly lower than the non-immunized (Gr-III) animals (p < 0.05-0.01). The elevated levels of the enzymes had positive correlation with depressed erythrocytic indices, leucocytosis, eosinophilia, necropsy worm recovery, and hepatic lesion score in the respective groups. The increased concentrations of the enzymes revealed two clearly demarcated stages: (a) remarkably elevated AST (40.8%) and ALT (140.0%) levels during the prepatency, signifying traumatic lesions inflicted by the F. gigantica adolescercariae and (b) the significant increase in AP (107.9%), suggestive of bile duct hyperplasia, cholangitis, periportal fibrosis, and biliary obstruction etc. from sixth week PI onward. None of healthy controls developed clinical signs and had normal hematological and serum enzyme profiles. Diagnostic significance of these marker enzymes in the disease forecasting and in time application of control strategies to combat tropical fasciolosis in buffaloes in the endemic areas has been discussed.

The effect of temperature and humidity on longevity of metacercariae of Fasciola gigantica

Studies were undertaken on the viability of the metacercariae of Fasciola gigantica when stored in water at 13 degrees C for periods up to 23 weeks, exposed to the sunlight for up to 8 h or stored at a range of temperatures and humidities for up to 10 weeks. Excysted metacercariae were catergorized microscopically as viable (motile and undamaged), dubious (not motile and undamaged) or dead (visible necrosis). The infectivity of viable and dubious metacercariae and unselected reference metacercariae held in water at 7 degrees C for 20 days or longer was assessed by comparing numbers of flukes recovered from infected Merino sheep. Mean recovery rates were 54.6%, 7.2% and 37.2%, respectively, for viable, dubious and unselected metacercariae. Metacercariae immersed in water remained viable longer than those allowed to desiccate. Viability was promoted by decreasing temperature and increasing humidity. Exposure to direct sunlight killed metacercariae within 8 h. Results indicated that in lowland Indonesian irrigated rice paddies, metacercariae immersed in water are likely to survive for less than 5 weeks while those that become desiccated will survive less than 2 weeks. This information, together with the option of exposing fresh rice stalks to direct sunlight before feeding them to livestock, can assist farmers in reducing infection with F gigantica.

Host differences in response to trickle infection with Fasciola gigantica in buffalo, Ongole and Bali calves

Progressive weight gain, faecal egg counts, packed cell volume, percent eosinophils in blood, serum antibody and serum levels of glutamate dehydrogenase and gamma-glutamyl transpeptidase were recorded in seven swamp buffalo (Bubalis bubalis), 7 Ongole (Bos indicus) and four Bali calves (Bos sundiacus) which were infected orally with 15 metacercariae of Fasciola gigantica twice weekly for 32 weeks. Similar observations were made on four buffalo, 4 Ongole calves and 3 Bali calves maintained fluke-free as controls. Flukes were counted at slaughter 36 weeks after initial infection. Mean daily weight gains of infected Bali (228 +/- 100 (SD) g/day) and infected Ongole calves (328 +/- 57 (SD) g/day) were lower (p = 0.026 and 0.067, respectively) than those of control calves (405 +/- 107 (SD) g/day), but infected buffalo calves (379 +/- 78 (SD) g/day) had similar weight gains to those of the controls (p = 0.57). Throughout the trial, faecal Fasciola egg counts in buffaloes were about one-fifth of counts of Ongole calves, and counts in Bali calves were intermediate. Ongole calves had three times the number of flukes at slaughter in their liver compared to buffalo and Bali calves, which had similar numbers. However, there was evidence that Bali calves had acquired a degree of resistance about 24 weeks after infection commenced and may have lost adult flukes as a consequence.

The effect on infection of irradiated Fasciola gigantica (liver flukes) on goats (Capra hircus Linn) blood values

This experiment was carried out to study the effect of infection Fasciola gigantica irradiated by using 60 Co to goat’s blood values. Twenty local male goats, ten to twelve old months, 15-20 kg of body weight were used for this study. The animals were divided into 5 groups consisting of four replications. Three groups received irradiated metacercariae of Fasciola gigantica using 45, 55 and 65 Gy respectively. One group was the positive control (goats were infected by non-irradiated metacercariae) and another one was the negative control (goats were not infected by metacercariae). Each goat received 350 metacercariae. Body weight, Eosinofil, PCV and Hb were measured every weeks for 20 weeks. The result indicated that pathogenicity of irradiated Fasciola gigantica was reduced. In all parameters, among negative control group and three irradiation-groups showed non significant (P>0.05). Key Words : Fasciola gigantica, Irradiated, Eosinofil, Packed Cell Volume, Haemoglobin

The effect of the liver fluke Fasciola gigantica infestation on the leucocyte eosinophil cell profile on sheep

Eosinophil is one of the major leucocyte cell in the blood which specifically reacted on parasite infection, thus it is important to determine its profile against the F. gigantica infection. The aims of this study is to determine the differences of the eosinophil count profiles on the different breed of sheep infected with F. gigantica and its relation with the resistance of sheep bred against parasitic disease. Four groups of sheep consist of Indonesian Thin Tail (ITT) sheep, Merino sheep, backcross sheep (10 families) and F2 sheep were infected with 300 metacercariae of Fasciola gigantica . The total sheep used in this trial is 621. Those sheep were observed for 12 weeks and the blood samples were collected every 2 weeks after infection. The results showed that total eosinophil counts in all infected sheep increased after two weeks post infection and ITT sheep showed the highest counts. On the other hand, the mean fluke counts on ITT sheep is the lowest compared with the other groups of sheep. Merino and F2 sheep had the highest mean fluke counts. Three families of backcross sheep had the mean flukes count similar to ITT sheep and the other 7 families were similar to the Merino sheep. In conclusion, the highest total eosinophil count at the early stage of infection on ITT sheep might be related with the genetic resistance, which was showed by the lowest flukes count, and the resistance was inherited to some of the backcross sheep, which had similar flukes count with ITT sheep. Key words: Fasciola gigantica , eosinophil, sheep

The responses of eosinophil and packed cell volume (PCV) on sheep infected with Fasciola gigantica

The responses of eosinophil and packed cell volume (PCV) values were verified in infected sheep, in order to identify whether these parameters could be used to predict the flukes burden and their correlation with breed resistance. Fifteen Indonesian thin tail sheep (ET), 9 Merino sheep and 148 backcross sheep generated from mating of Merino sheep and F1 sheep (Merino X ET cross) were infected with 300 metacercariae of Fasciola gigantica . The blood samples were collected every 2 weeks by using EDTA venoject tubes in order to determine the amount of eosinophils and the PCV value. After 14 weeks of infection all of sheep were killed and the liver was collected in order to determine the number of flukes. The results showed that the amount of eosinophils increased 2 weeks after infection and reached the peak at week 4 after infection. The average of eosinophils in ET appeared higher than the other 2 breeds (Merino was the lowest and the backcross was in between). The correlation between the number of flukes recovered from the liver and the eosinophil counts were positive in ET and Merino, but negative in the backcross sheep. The PCV values remained constant along the trial, except at week 14 after infection; the PCV values were slightly decreased in backcross sheep and Merino sheep, but not in ET sheep. The correlation between number of flukes in the liver and the PCV values were negative in all breeds of sheep. These results suggested that the eosinophilic and PCV’s response of ET were higher compared to backcross and Merino sheep, thus that responses were thought to be associated with the resistant phenomenon. Key words: Fasciolosis , eosinophil, PCV, sheep

Antibody fluctuations of infected cattle with Fasciola gigantica and the effect of triclabendazole treatment

Observation on the antibody fluctuations of infected cattle with metacercariae of Fasciola gigantica and the effect of triclabendazole treatment were made by means of ELISA technique. Seven cattle were infected with 700 metacercariae and one cattle remained uninfected, as negative control animal. Treatment with triclabendazole was given to 6 cattle, when the mean antibody levels of infected cattle reached the peak, and the other one remained untreated, as positive control animal. One week after treatment the mean antibody levels started to drop and then decreased gradually. After eight weeks of treatment, the mean antibody levels of the treated cattle reached the lowest level or the same value as before infection, thereafter, 6 cattle were reinfected with different dosages of metacercariae of F. gigantica . Two cattle were infected with 400 metacercariae, the other two were infected with 600 metacercariae and the rest of them were infected with 800 metacercariae. The results showed that the immunological responses of re-infected cattle are quicker (5 weeks after infection) and the peak of the antibody levels are higher (ELISA OD = 1.7) than after the first infection (11 weeks after infection and ELISA OD = 1.2). However, after re-infection, there were no significant different on the antibody fluctuations and antibody levels among the infected group, although those cattle received different dosages. Key words : Antibody, cattle, Fasciola gigantica , ELI

Studies on the viability of metacercariae of Fasciola gigantica

The viability of metacercariae of Fasciola gigantica was tested by in vitro and in vivo methods. In vitro testing was based upon the motility of juvenile flukes within the inner cyst as examined under the light microscope. In vivo testing was undertaken through experimental infections of rabbits (two groups) and natural definitive hosts, lambs (one group). In the first group, out of six rabbits each given 25 metacercariae, worm establishment only took place in one rabbit with a single fluke recovery on 60 days post infection. In the second group of six rabbits each given 200 metacercariae, five were infected, with two or three flukes per host. All the lambs given 250 metacercariae became infected showing prevalences of 7.2–40% in comparison with rabbits in which low prevalences (0–4%) were recorded. The results indicated that even viable metacercariae which were already tested in vitro could not readily establish in rabbits. Such variability in worm establishment suggests that immunological and chemotherapeutic studies in rabbits infected with F. gigantica are likely to be unreliable.

Studies on the viability of metacercariae of Fasciola gigantica

The viability of metacercariae of Fasciola gigantica was tested by in vitro and in vivo methods. In vitro testing was based upon the motility of juvenile flukes within the inner cyst as examined under the light microscope. In vivo testing was undertaken through experimental infections of rabbits (two groups) and natural definitive hosts, lambs (one group). In the first group, out of six rabbits each given 25 metacercariae, worm establishment only took place in one rabbit with a single fluke recovery on 60 days post infection. In the second group of six rabbits each given 200 metacercariae, five were infected, with two or three flukes per host. All the lambs given 250 metacercariae became infected showing prevalences of 7.2-40% in comparison with rabbits in which low prevalences (0-4%) were recorded. The results indicated that even viable metacercariae which were already tested in vitro could not readily establish in rabbits. Such variability in worm establishment suggests that immunological and chemotherapeutic studies in rabbits infected with F. gigantica are likely to be unreliable.

Separation of outer cysts from metacercariae of Fasciola gigantica in an aqueous two-phase system.

The outer cysts (Oc) of Fasciola gigantica metacercariae (Mc) were separated in an aqueous two-phase system composed of polyethylene glycol and dextran in distilled water. A large number of separated Mc without Oc were recovered in the bottom layer rich in dextran in the system. Ten separated Mc in the layer were used to inoculate the mouse with a syringe and juveniles were recovered from the animals on the 14th day. When the number of juveniles recovered was compared with that from the mice infected orally with the same number of Mc, there was a significant difference between them (P < 0.05). The former method is easier than the latter for inoculation.

On the viability of Fasciola gigantica metacercariae ingested by Lymnaea auricularia.

The effect of ingestion by Lymnaea auricularia on the viability and infectivity of Fasciola gigantica metacercariae was studied. The cyst wall was unaffected by the snail's digestive processes. Two rabbits, each infected with 50 ingested metacercariae, died at 83 and 87 days post-infection. Eight and 10 immature flukes were recovered from the livers, indicating that the metacercariae had remained infective after passing through the intestine of the snail.

Protective effect of irradiated metacercariae of Fasciola gigantica and irradiated cercariae of Schistosoma bovis against fascioliasis in goats.

Sensitisation of goats for eight weeks with metacercariae of Fasciola gigantica gamma-irradiated at 3 kr resulted in significant resistance to an homologous challenge with normal metacercariae. However, serum sorbitol dehydrogenase assay suggested that, whereas little damage was produced by immunising infections, considerable hepatic damage was caused by flukes remaining from challenge infections. On the other hand sensitisation with cercariae of Schistosoma bovis gamma-irradiated at 3 kr did not stimulate any resistance against heterologous challenge with F. gigantica.

The protective effect of irradiated metacercariae of Fasciola gigantica against homologous challenge in sheep.

Five lambs were each sensitized with 400 metacercariae of Fasciola gigantica irradiated at 3 kr gamma rays. Eight weeks later, they were each challenged together with 5 controls with 500 non-irradiated metacercariae. Eight weeks later, all of the animals were necropsied and the worm burdens determined. The lambs which received the sensitizing infections had 80% less worms than the controls. The sensitized lambs also showed less hepatic damage compared with the controls as indicated by lower levels of the serum enzyme glutamate dehydrogenase. The blood indices showed insignificant reductions in the sensitized lambs whereas marked reductions were found in the erythrocytes, packed cell volume and haemoglobin values of the challenge controls. Bilirubinaemia was also evident in this latter group.

The effect of niclofolan on desert sheep experimentally infected with immature Fasciola gigantica.

Eight desert sheep were each infected orally with 500 metacercariae of Fasciola gigantica and, after 4 weeks, four of the animals were given niclofolan orally at the recommended therapeutic dose rate of 7 mg/kg, the other four remaining as controls. One week later, the animals were slaughtered and the fasciocidal effect of the drug was evaluated on the basis of worm burden, haemogram, some plasma constituents, and gross and histopathological lesions of the liver, as indicators of efficacy. The treatment was found to be ineffective, the degree of infection remaining the same as in the untreated control group. The experiment was repeated using eight infected sheep: four were given the drug orally at a dose rate of 10.5 mg/kg, i.e., 1.5 times the recommended dose; and the same parameters were measured as described above. The drug failed to cure the infected sheep, and caused depression, anorexia and weakness. In a third experiment six sheep were infected as before and three were treated with niclofolan by deep i.m. injection at the recommended therapeutic dose of 2 mg/kg. A week later the animals were killed and examined as before. The drug was effective in treating the infection and produced no untoward effects except for transient signs of pain at the site of injection. It seems possible that the oral dose, unlike the i.m. dose, of niclofolan is not absorbed and/or metabolized sufficiently to prevent elimination of the infection.

Passage of Host Serum Components, including Antibody, across the Digestive Tract of Dermacentor variabilis (Say)

(14 wk postinfection), the death rates were 36 and 40% in group A and B respectively, compared to 8% in the noninfected control (Table I). Metacercarial production was high and continued for at least 50 days after the prepatent period (Table I). The procedure described appears to be valuable and useful for the cultivation of k postinfection), the d ath rates w re 36 40% in group A and B resp ctively, comed to 8% in the no infect d control (Table aquatic species of Lymnaea and for mass producti n of metacercariae of Fasciola gigantica. The m thod is simple and time saving and makes possible mass production of snails. The growth rate of juvenile snails was fast and the mortality of both noninfected and infected snails was low. ic species of Lymnaea nd for mass proio of metacercariae of Fasciola gi antie ethod is simple and time saving and s possible mas production of snails. The t rate of juvenile snails was fast and the

The effect of γ-irradiation on Fasciola gigantica infectivity to hamsters

The effect of Cobalt-60 irradiation at graded doses on the infectivity of Fasciola gigantica metacercariae was studied in hamsters. Since no worm was recovered from the hamster liver when the metacercaria was irradiated at doses above 4 krad, it was concluded that only irradiation beyond this level sufficiently attenuated Fasciola gigantica metacercaria enough to prevent immature parasites from getting into the liver.