Gigantica Infection Research Articles

Associations between trematode infections in cattle and freshwater snails in highland and lowland areas of Iringa Rural District, Tanzania.

The epidemiology of trematode infections in cattle was investigated within highland and lowland areas of Iringa Rural District, in southern Tanzania. Fecal samples were collected from 450 cattle in 15 villages at altitudes ranging from 696 to 1800 m above the sea level. Freshwater snails were collected from selected water bodies and screened for emergence of cercariae. The infection rates in cattle were Fasciola gigantica 28·2%, paramphistomes 62·8% and Schistosoma bovis 4·8%. Notably, prevalence of trematode infections in cattle was much higher in highland (altitude > 1500 m) as compared with lowland (altitude < 1500 m) areas and was statistically significant (P-value = 0·000) for F. gigantica and paramphistomes but not for S. bovis. The snails collected included Lymnaea natalensis, Bulinus africanus, Bulinus tropicus, Bulinus forskali, Biomphalaria pfeifferi, Melanoides tuberculata and Bellamya constricta with a greater proportion of highland (75%) than lowland (36%) water bodies harbouring snails. Altitude is a major factor shaping the epidemiology of F. gigantica and paramphistomes infections in cattle in Iringa Rural District with greater emphasis upon control needed in highland areas.

Protection against Fasciola gigantica infection in mice by vaccination with recombinant juvenile-specific cathepsin L

Fasciola gigantica cathepsin L1H (FgCatL1H) is one of the major cathepsin L released by juveniles of F. gigantica to aid in the invasion of host's tissues. Due to its high sequence similarity with other cathepsin L (CatL) isoforms of late stage F. gigantica, it was considered to be a good vaccine candidate that can block all CatL-mediated protease activities and affect juveniles as well as adult parasites. In this study, recombinant proFgCatL1H protein expressed in yeast, Pichia pastoris, system was mixed with Freund's adjuvants and used to subcutaneously immunize mice that were later challenged with metacercariae of F. gigantica. The percentage of worm protection in the rproFgCatL1H-vaccinated mice compared to the non-immunized and adjuvant control mice were approximately 62.7% and 66.1%, respectively. Anti-rproFgCatL1H antisera collected from vaccinated mice reacted specifically with rproFgCatL1H and other cathepsin L isoforms of F. gigantica, but the antibodies did not cross react with antigens from other trematode and nematode parasites, including Eurytrema pancreaticum, Opisthorchis viverrini, Fischoederius cobboldi, Cotylophoron cotylophorum, Gigantocotyle explanatum, Paramphistomum cervi, and Setaria labiato-papillosa. The levels of IgG1 and IgG2a in mouse sera increased significantly at two weeks after immunization and were highest during the sixth to eighth weeks after immunization. The IgG1 level was higher than IgG2a at all periods of immunization, implicating the dominance of the Th2 response. The levels of IgG1 and IgG2a in the immune sera were shown to be strongly correlated with the numbers of worm recovery, and the correlation coefficient was higher for IgG1. The levels of serum aspartate aminotransferase and alanine transaminase were significantly lower in the sera of rproFgCatL1H-vaccinated mice than in the infected control mice indicating a lower degree of liver damage. This study demonstrated a high potential of FgCatL1H vaccine, and its efficacy is currently being studied in the larger economic animals.

Comparative Studies on Triclabendazole and Mirazid in Guinea Pigs Experimentally Infected with Fasciola gigantica

Forty Guinea pigs (1-2 month old) were divided into 4 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 gigantic metacercariae (FGM) for each as a single dose by using stomach tube. Gps (3 and 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. 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. It could be concluded that; the triclabendazole is more effective than mirazid in the treatment of Fasciola gigantica infection. Further research should be done for more precise knowledge about the efficacy of mirazid as a fasciolicidal drug.

Effects of Experimental Fasciola Gigantica Infection on Serum Testosterone Profiles and their Relationship with Semen Characteristics of Yankasa Ram

This study was designed to evaluate the effects of Fasciolosis on serum testosterone profiles and semen characteristics of Yankasa rams. Twelve, apparently healthy, Yankasa rams aged 18-24 months were randomly divided into two groups (infected group A and control group B) with seven and five rams, respectively. The rams werekept under intensive management in different pens throughout the study period. Group A rams were inoculated with 800 metacecariae orally and monitored for 12 weeks Post Infection (PI). Clinical signs were manifested 2 weeks PI. Faecal examination revealed Fasciola eggs at week 7 PI in group A. Three mL of blood were collected aseptically via the jugular vein at 30 min interval, weekly between 08:00-9:00am for serum testosterone assay. Testosterone assay was done using ELISA technique. There was significant decrease in testosterone concentration in group A at different time intervals of the weeks of post-infection. The semen analysis showed the lowest mean (±SEM) of semen volume, semen motility, semen concentration, of group A, as (0.01±0.0 mL), (3.6±2.4%), (16.1±4.2%) compared to group B with mean (±SEM) (1.6±0.1 mL), (93.0±1.2%), (440.0±13.0%) at week 7 post- infection, respectively. This study revealed that Fasciolosis has a great impact on sheep mainly by diminishing their reproductive efficiency and rendering infected rams infertile. It is concluded that F. gigantica infectionhad advanced effects on testosterone production and semen quality of Yankasa rams.

Effect of induced Fasciola gigantica infection during pre-patency on the performance of buffalo calves fed on different percentage of protein.

Thirty growing Murrah buffalo calves (8-12months of age, 109.85±2.43) were rearedin parasite free conditions and randomly divided into three equal groups as per CRD. They were fed on iso-caloric (2.01MEMcal/Kg diet) diets containing standard protein (SP) diet at 100%, 90% of SP (medium protein, MP) and 80% of SP (low protein, LP) of the protein requirements (Kearl 1982). After 21days of feeding, each group was further subdivided into two sub-groups (A & B). Animals in sub-groups 'A' served as non-infected control, while in sub group 'B' were orally infected with Fasciola gigantica metacercarie (mc; 1,000 each). A metabolic trial of 40days post infection was carried out in control and parasitized animals. Intake of digestible dry matter, organic matter and acid detergent fibre (ADF) was significantly higher (P<0.05) in SP group compared to LP group. The digestibility of crude protein (CP) and ADF was significantly higher in SP group compared to MP and LP groups. The digestible crude protein (DCP) and total digestible nutrients (TDN) intakes (g/kgW(0.75)) were also significantly (P<0.001) higher in SP than MP and LP groups. However, DCP intake was significantly (P<0.001) lower in infected subgroups compared to control subgroups. Intake and balance (g/d) of nitrogen, calcium and phosphorus were significantly (P<0.01) higher in SP than MP and LP groups. The average daily gain of buffalo calves fed on SP Uninfected (SPU), SP Infected (SPI), MPU, MPI and LPU, LPI groups was 333, 178, 356, 144, 222 and 144g and was significantly (P<0.01) lower in animals fed LP ration. The feed conversion ratio (FCR) was also significantly (P<0.01) higher in infected sub-groups as compared to respective control groups. The results showed that a SP diet substantially improved the overall performance of buffalo calves in control and infected groups and reduced adverse effect of F. gigantica infection.

Effect of feeding deoiled mahua (Bassia latifolia) seed cake on the growth performance, digestibility and balance of nutrients in cross-bred calves during pre-patent period of Fasciola gigantica infection.

A study was conducted to assess the growth performance and nutrient utilization of cross-bred calves serially infected with Fasciola gigantica and/or supplemented with deoiled mahua seed cake (DMSC) during pre-patent period of infection. Twenty healthy cross-bred (Holstein Friesian×Haryana) male calves aged 6-7months with an initial average live weight of 79.6±2.71kg were divided into four treatment groups (CON, CON-INF, DMC and DMC-INF) of five animals each following randomized block design. DMSC was included in the concentrate mixture of DMC and DMC-INF groups at 100g/kg level. Animals of groups CON-INF and DMC-INF were given an infection of 200 metacercariae (mc) of F.gigantica as serial infection dose of 50mc twice weekly over a period of 2weeks. A metabolism trial at 40-49days post-infection and growth trial of 145days duration were conducted. The average daily gain (ADG) and feed conversion ratio (FCR) were significantly (p<0.05) lower in CON-INF group as compared to others. The ADG and FCR were significantly (p<0.05) higher in DMC-INF as compared to CON-INF. The intake and digestibility of nutrients were not affected by serial infection with F.gigantica during pre-patent period. However, significantly (p<0.001) higher urinary excretion and significantly (p<0.001) lower nitrogen balance were observed in CON-INF group as compared to other three groups. The nitrogen balance was significantly (p<0.001) improved in DMC-INF group as compared to CON-INF group. From the results, it may be deduced that the supplementation of deoiled mahua seed cake at 100g/kg level in the concentrate mixture has improved the growth performance and nitrogen utilization in cross-bred calves infected with F.gigantica.

Role of oxidative stress in concomitant occurrence of Fasciola gigantica and leiomyoma in cattle

Fasciola gigantica is a parasitic helminth that predominantly infects the liver and bile ducts of cattle and causes great losses of cattle production in the southwestern regions of Iran. The purpose of the present study was to find out the possible relationship between the extent of liver destruction and oxidative stress by estimating the level of MDA, and SOD and GPX enzymes in the liver of cattle infected with F. gigantica. Studies were carried out on 49 infected and 20 healthy livers. Based on the results, the SOD activity of the infected livers was substantially lower than those of the healthy ones. As in the livers with more damage, a significant decrease was observed in the SOD activity. Although the GPX activity of the control livers and the livers with low damage showed no statistically significant variation this value was significantly different between the livers with high injury and the control ones. The MDA level of the infected animals was significantly higher than the non-infected animals. In addition, the level of MDA production showed a parallel correlation with the severity of infection. By histological examination, the lesions in infected livers were varied from tortuous, organized fibrotic areas in or around the hepatic lobules, cirrhosis, and chronic catarrhal cholangitis to fresh migratory tunnels filled with RBC and eosinophils. Multifocal and relatively homogenous populations of densely packed spindle cells with blunt-ended nuclei, arranged in broad interlacing fascicles were noted in samples of 10 infected livers. Based on the histological features by routine and special staining and the results of the immune labeling, the tumors were diagnosed as hepatic leiomyoma. To the best of our knowledge, this is the first report on the concomitant occurrence of Fasciola gigantica infection and leiomyoma in cattle. Therefore, there is considerable evidence indicating that the severity of hepatic damage in fasciolosis is causally associated with the extent of intrahepatic oxidative stress. Future research is necessary in order to clarify the complex host–parasite interactions and to better define the oncogenic implications of F. gigantica infection.

English

Fasciolosis is an important helminth disease of livestock and other ruminants. A cross sectional study to determine the prevalence of Fasciola gigantica in cattle was carried out in 9 randomly selected farms and 1 slaughter house between February and May 2012. Faecal and blood samples were collected from 186 cattle in the farms and 200 cattle at slaughter. The faecal samples were analysed using the formol ether sedimentation technique and the blood by Indirect ELISA kit (Bio-X-Diagnostic, ID VET Jemelle-Belgium) to detect F. gigantica eggs and antibodies to F. gigantica antigens respectively. Of the 200 faecal samples collected at slaughter, 39(19.5%) had F. gigantica eggs; as compared to 27 (14.5%) positives out of the 186 samples collected from the farms; giving an overall prevalence rate of 66 (17.1%). There was no significant difference (P>0.05) between prevalence of infection of cattle sampled in the farms and slaughter house. 23 (11.5%) of the sera prepared from the 200 blood samples obtained at slaughter had antibodies to F. hepatica antigens, as against 5(2.6%) for sera from 186 blood samples collected in the farms; giving an overall seroprevalence of 28(7.3%). There was significant difference (P 0.05). No statistical difference was observed in breed prevalence. This study has established F. gigantica prevalence of 17.1% and 7.3% by coprological and serological examinations of faeces and blood of cattle in Zaria. It is recommended that cattle should be dewormed regularly and further serological screening be embarked in other Local Government Areas of Kaduna State, so as to know the current status of F. gigantica infection in cattle.

In-vitro and in-vivo assessment of the effect of soybean extract on Fasciola gigantica infection in comparison with triclabendazole

Objective The aim of this study was to assess the effect of genistein (soybean extract) on fascioliasis. Background Continued use of triclabendazole (TBZ) as the major antifascioliasis drug has resulted in resistance. Genistein, a major isoflavone in soybean extract, shows activity against different parasites. Materials and methods This was an in-vivo study that included 28 male New Zealand rabbits grouped as follows: GI, infected and nontreated; GII, infected and treated with TBZ; GIII, infected and treated with soybean extract; GIV, normal control group; GV1, not infected and treated with TBZ; and GV2, not infected and treated with soybean extract. Treatment started on the 80th day postinfection (d.p.i.) Stool examination by formol ether concentration and egg count per gram of feces were performed on day 0 of treatment, 3rd and 7th day post treatment (d.p.t.) Cure rate and fecal egg count reduction of TBZ and soybean extract were compared. Rabbits were killed on the 95th d.p.i. Liver sections were stained with hematoxylin & eosin (HE GII, TBZ exposed; GIII, soybean extract exposed; and GIV, incubated with DMSO (soybean solvent). Adult Fasciola DNA was extracted for electrophoresis. Results Fecal egg count reduction of soybean extract was 41.6% on the 3rd d.p.t. and 95.8% on the 7th d.p.t. compared with 100% of TBZ on the 3rd and 7th d.p.t. The cure rate of this extract was 0% on the 3rd d.p.t. and 83.3% on the 7th d.p.t compared with 100% of TBZ on the 3rd and 7th d.p.t. Soybean extract improved most hepatic lesions shown by H&E staining and decreased the apoptotic changes detected by caspase-3 immunostaining. It also induced apoptotic damage of Fasciola gigantica DNA. Conclusion Soybean extract can be used in the treatment of fascioliasis to decrease the emergence of TBZ resistance.

An enzyme-linked immunosorbent assay for diagnosis of Fasciola gigantica infection in cattle and buffaloes.

The enzyme-linked immunosorbent assay (ELISA) was evaluated for the diagnosis of Fasciola gigantica infection in cattle and buffaloes. The excretory-secretory (E-S Ag) antigen of F. gigantica adult flukes obtained after invitro incubation was used as an antigen. The test was conducted with 276 sera collected from cattle and buffaloes which included 22 sera each from naturally infected cattle and buffaloes (known positive serum) and with similar number of samples with healthy cattle and buffaloes (known negative serum). The positive results were observed in 18 and 19 of the sera from naturally infected cattle and buffaloes with sensitivity of 81.8 and 86.3% respectively. Out of 188 serum samples which were found negative on faecal examination 32 (34%) sera of cattle and 40 (42.5%) sera of buffaloes were found positive by ELISA respectively. The sensitivity of the test was found to be 91.6 and 95.6% in cattle and buffaloes respectively.

Immunodiagnosis of Egyptian Human Fasciolosis Gigantica Using Fas1 and Fas2 Cysteine Proteinase Antigens

Fasciolosis caused by Fasciola gigantica is one of the major public health problems in the world including Egypt. Immunodiagnostic methods are more applicable for their better sensitivity and specificity than other methods. The present study was conducted to cysteine proteinase (CP) antigens of F. gigantica in IgG-ELISA to diagnose human fasciolosis. IgG-ELISA with 2 cysteine proteinases of 27 kDa (Fas1) and 29 kDa (Fas2), obtained from the regurgitated materials of adult worms, were evaluated using serum samples from 90 Egyptian patients infected with F. gigantica, 55 patients with other parasitic infections and 50 healthy volunteers. The diagnostic sensitivity and specificity of Fas1 for detection of F. gigantica infection were 91.1% and 89.1%, respectively. The positivity of the assay was 95%. The positive and negative predicted values were 91% and 86%, respectively. These data suggest that IgG-ELISA with Fas1 is highly sensitive and specific assay and could be used for the immunodiagnosis of human fasciolosis.

Detection of &lt;i&gt;Fasciola gigantica&lt;/i&gt; antibodies using Pourquier ELISA kit

A cross sectional study using Pourqueir Enzyme Linked Immunorsobent Assay (ELISA) screening kit for Fasciola antibodies was conducted in breeding herds in two Local Government Areas of Adamawa state. The objectives were to determine the presence of Fasciola gigantica antibodies as a way of demonstrating the use of the ELISA screening method in breeding cattle, compare the occurrence of the disease in the two areas and to also determine if the kit can serve as a feasible antemortem diagnostic and screening approach in breeding herd in a tropical developing country with possible under current infection. Two hundred and twenty five (225) serum samples from breeding herds were randomly collected and used. The samples were drawn from both matured and immature male and female cattle of white Fulani, Adamawa Gudali, Red Bororo and Sokoto Gudali breeds. An indirect ELISA analysis method was employed using the protocol designed by the manufacturer. The validity of the test for each plate was carried out. Results confirmed the presence of Fasciola gigantica antibodies: 162 positive cases out of the 225 cattle sampled, which gave an overall prevalence of 72%. Antibodies detected by the ELISA reader indicates that the cattle were affected by the disease at different infestation levels (0=28%, +=11.1%, ++=13.7%, +++=47.1%). Analysis with a t-test paired sample statistics showed that there was no significant difference in fasciolosis (p>0.05) between the 2 local government areas. The assay detected antibodies in sera from cattle with natural Fasciola gigantica infection. Therefore the kit was found very effective in detection of fasciola infection in live animals. We conclude that the kit will be a valuable tool for diagnosing Fasciola gigantica infection in cattle.

Protection Against Fasciola gigantica using Paramyosin Antigen as a Candidate for Vaccine Production

Yet no vaccine to protect ruminants against liver fluke infection has been commercialized. In an attempt to develop a suitable vaccine against Fasciola gigantica (F. gigantica) infection in rabbits, using 97 kDa Pmy antigen. It was found that, the mean worm burdens and bile egg count after challenge were reduced significantly by 58.40 and 61.40%, respectively. On the other hand, immunization of rabbits with Pmy induced a significant expression of humoral antibodies (IgM, total IgG, IgG1, IgG2 and IgG4) and different cytokines (IL-6, IL-10, L-12 and TNF-alpha). Among Ig isotypes, IgG2 and IgG4 were most dominant Post-infection (PI) while, recording a low IgG1 level. The dominance of IgG2 and IgG4 suggested late T helper1 (Th1) involvement in rabbit's cellular response. While, the low IgG1 level suggested Th2 response to adult F. gigantica worm Pmy. Among all cytokines, IL-10 was the highest in rabbits immunized with Pmy PI suggesting also the enhancement of Th2 response. It was clear that the native F. gigantica Pmy is considered as a relevant candidate for vaccination against fascioliasis. Also, these data suggested the immunoprophylactic effect of the native F. gigantica Pmy which is mediated by a mixed Th1/Th2 response.

Disruption of estrus and conception in the acute phase of Fasciola gigantica infections in Yankasa ewes

The effect of the hepatic migratory phase of Fasciola gigantica infections on estrus response to synchronization, conception rates, serum enzyme and biochemical changes in Yankasa ewes was investigated. Twelve adult Yankasa ewes were randomly assigned to one of two groups of 6 animals each. The ewes in Group 1 were each infected with 1,200 metacercaria of F. gigantica each while Group 2 served as non infected controls for the study. The ewes in both groups were then synchronized for estrus at 7 weeks post infection (WPI), and intact rams were introduced for heat detection and breeding. Pregnancy was confirmed by progesterone levels and non-return to estrus 21 days post breeding. Estrus response was 66.6 and 100% in infected and controls, respectively, but all infected animals returned to estrus by 42 days post breeding, indicating conception failure or an early embryonic death. Pathophysiological signs included anorexia, progressive anemia, emaciation and significant hypoproteinemia. Hepatic dysfunction was indicated by the significant increases in liver enzymes; aspartate amino transferase, alanine amino transferase and alkaline phosphatase levels in infected ewes and at post mortem hepatic fibrosis of the liver with intra-hepatic hemorrhage was observed. It is concluded that fasciolosis has an adverse effect on conception and establishment of the fetus in the acute migratory phase. Key words: Fasciola gigantica, estrus, conception, ewes, productivity, Nigeria.

Th1 and Th2 cytokine gene expression in primary infection and vaccination against Fasciola gigantica in buffaloes by real-time PCR

Th1 and Th2 cytokine gene expression in buffalo calves during primary infection with Fasciola gigantica as well as in response to immunization with the parasite recombinant fatty acid binding protein (rFABP) and recombinant glutathione S-transferase (rGST) proteins was measured at 14th week of infection by real-time PCR with the double-stranded DNA-binding dye SYBR Green. Experimental animals were randomly distributed into FABP, GST, cocktail, challenge and healthy groups. Animals in groups FABP and GST were immunized with 400 μg rFABP and rGST, respectively, and cocktail group with a mixture of 400 μg each of rFABP and rGST in the neck and thigh muscles. All animals received three immunizations at 3-week interval. Calves were challenged per os with 400 viable metacercariae along with the unimmunized challenge control group 1 month after the last immunization. Expression of various cytokines in response to the immunization and parasite primary infection was measured by real-time PCR. Expression of IL-2 (4.5-fold) and IFN-γ (3.2-fold), followed by IL-6 (1.7-fold) and IL-4 (1.6-fold), with downregulation of TNF-α and IL-10 was observed in response to F. gigantica infection in these animals. However, there was a sharp increase in the expression of the IL-4 (211.93 and 111.81-fold) and IL-6 mRNA (219.22 and 48.29-fold) to GST and FABP immunizations, respectively. A downregulation of the IL-1α, a Th1 cytokine in response to FABP and GST immunization in these calves, was also observed. Overall, a mixed type of Th1 and Th2 cytokine environment was evoked to chronic F. gigantica infection and immunization with the above two recombinant proteins in buffaloes.

Molecular cloning, characterization and functional analysis of a novel juvenile-specific cathepsin L of Fasciola gigantica

Cathepsin L proteases are a major class of endopeptidases expressed at a high level in Fasciola parasites. Several isoforms of cathepsin L were detected and they may perform different functions during the parasite development. In this study, a complete cDNA encoding a cathepsin L protease was cloned from a newly excysted juvenile (NEJ) cDNA library of Fasciola gigantica and named FgCatL1H. It encoded a 326 amino acid preproenzyme which shared 62.8–83.1% and 39.5–42.9% identity to Fasciola spp. and mammalian cathepsins L, respectively. All functionally important residues previously described for cathepsin L were conserved in FgCatL1H. Phylogenetic analysis demonstrated that FgCatL1H belonged to a distinct group, clade 4, with respect to adult and other juvenile Fasciola cathepsin L genes. FgCatL1H expression was detected by RT-PCR, using gene specific primers, in metacercariae and NEJ, and the expression gradually decreased in advanced developmental stages. A recombinant proFgCatL1H (rproFgCatL1H) was expressed in the yeast Pichia pastoris, affinity purified, and found to migrate in SDS-PAGE at approximately 47.6 and 38.3kDa in glycosylated and deglycosylated forms, respectively. The molecular mass of the activated mature rFgCatL1H in glycosylated form was approximately 40.7kDa. Immunoblotting and immunohistochemistry using rabbit antibodies against rproFgCatL1H showed that FgCatL1H was predominantly expressed in epithelial cells of the digestive tract of metacercariae, NEJs and juveniles of F. gigantica. FgCatL1H could cleave the synthetic fluorogenic substrate Z-Phe-Arg-MCA preferentially over Z-Gly-Pro-Arg-MCA at an optimum pH of 6.5. It also showed hydrolytic activity against native substrates, including type I collagen, laminin, and immunoglobulin G (IgG) in vitro, suggesting possible roles in host tissue migration and immune evasion. Therefore, the FgCatL1H is a possible target for vaccine and chemotherapy for controlling F. gigantica infection.

Diagnosis of Fasciola gigantica infection using a monoclonal antibody-based sandwich ELISA for detection of circulating cathepsin B3 protease

A reliable monoclonal antibody (MoAb)-based sandwich enzyme-linked immunosorbent assay (sandwich ELISA) was developed for the detection of circulating cathepsin B3 protease (CatB3) in the sera from mice experimentally infected with Fasciola gigantica and cattle naturally infected with the same parasite. The MoAb 2F9 and biotinylated rabbit polyclonal anti-recombinant CatB3 antibody were selected due to their high reactivities and specificities to F. gigantica CatB3 antigen based on indirect ELISA and immunoblotting. The lower detection limit of the sandwich ELISA assay was 10, 100 and 400pg/ml, when applied for the detection of rCatB3 antigen and CatB3 in whole body (WB) of newly excysted juveniles (NEJ) and metacercariae (Met) of F. gigantica, respectively. This sandwich ELISA assay could detect F. gigantica infection from day 1 to 35 post infection and revealed that circulating level of CatB3 peaked at day 1 post infection. In contrast, the antibody detection by indirect ELISA could only demonstrate the antibody level from 35 days post infection. The reliability of the assay method was evaluated using serum samples from mice infected with F. gigantica or Schistosoma mansoni, and hamsters infected with Opisthorchis viverrini, as well as normal mice and hamsters. In addition, sera from cattle infected with Paramphistomum cervi, Strongylid, Trichuris sp. and Strongyloides sp., as well as sera from normal cattle were also assessed. In experimental mice, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate and accuracy of ELISA were 95%, 100%, 100%, 97.9%, 0%, 5.3% and 98.5%, while in natural cattle they were 96.7%, 100%, 100%, 98.5%, 0%, 3.4% and 98.9%, respectively. Hence, this assay method showed high efficient and precision for early diagnosis of fasciolosis by F. gigantica.

Genetically Confirmed Fasciola Hepatogigantica N.Sp

Identification of liver fluke species cannot be achieved by clinical, pathological, coprological or immunological methods. However, the differential diagnosis between F. hepatica and F. gigantica infection is very important because of their different pathological manifestations. Moreover, in countries where the two species co-exist, morphologically intermediate forms were reported. The present study aimed to identify these forms by the use of molecular characterization of DNA sequence. Based on morphometric criteria, adults of Fasciola hepatica, F. gigantica and intermediate forms were collected from naturally infected sheep and cattle from various regions of Sohag Governorate. A simple and rapid new method (QIAamp DNA Mini Kit) was used to isolate DNA from the worms and their RELP patterns were obtained after digestion of the PCR products with AvalI restriction enzymes. The result of a regular PCR experiment for the amplification of the selected 28S rDNA fragment with the designed primer set yielded identical 618- bp-long PCR products for the three types of Fasciola where the RFLP profile obtained from F. hepatica revealed four fragments of 628, 575, 165 and 95 bp, and F. gigantica generated three fragments corresponding to 628, 358 and 300 bp fragments whereas the intermediate forms revealed four fragments of 628, 541, 358 and 300 bp, which were similar to those ofF. gigantica but with a distinctive fragment of 541. These results confirmed that three species are present in our locality: F. hepatica, F. gigantica and an intermediate form which was named F. hepatogigantica n.sp. on basis of having few morphometric characters from F. hepatica (length and pattern of uterine coils) but genetically they were more related to F. gigantica.

Praziquantel treatment in trematode and cestode infections: an update.

Status and emerging issues in the use of praziquantel for treatment of human trematode and cestode infections are briefly reviewed. Since praziquantel was first introduced as a broadspectrum anthelmintic in 1975, innumerable articles describing its successful use in the treatment of the majority of human-infecting trematodes and cestodes have been published. The target trematode and cestode diseases include schistosomiasis, clonorchiasis and opisthorchiasis, paragonimiasis, heterophyidiasis, echinostomiasis, fasciolopsiasis, neodiplostomiasis, gymnophalloidiasis, taeniases, diphyllobothriasis, hymenolepiasis, and cysticercosis. However, Fasciola hepatica and Fasciola gigantica infections are refractory to praziquantel, for which triclabendazole, an alternative drug, is necessary. In addition, larval cestode infections, particularly hydatid disease and sparganosis, are not successfully treated by praziquantel. The precise mechanism of action of praziquantel is still poorly understood. There are also emerging problems with praziquantel treatment, which include the appearance of drug resistance in the treatment of Schistosoma mansoni and possibly Schistosoma japonicum, along with allergic or hypersensitivity reactions against praziquantel treatment. To cope with and overcome these problems, combined use of drugs, i.e., praziquantel and other newly introduced compounds such as triclabendazole, artemisinins, and tribendimidine, is being tried.

The pathology observed in experimental &lt;i&gt;Fasciola gigantica&lt;/i&gt; 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