Efficacy of herbal extracts and closantel against fenbendazole-resistant Haemonchus contortus.

This study assessed the efficacy of closantel vis-à-vis herbal extracts with known anti-parasitic properties, against fenbendazole-resistant nematodes in goats maintained under a semi-intensive system of management at the University goat farm, Jabalpur. Fifty goats were randomly assigned to five groups, each comprising 10 animals, irrespective of their breed, age and sex. Each animal in Group I, II and III was orally administered with aqueous leaf extracts of neem (Azadirachta indica) at 1 g/kg body weight, sitaphal (Annona squamosa) at 1.5 g/kg body weight and tobacco (Nicotiana tabacum) at 1 g/kg body weight, respectively, whereas Group IV was an untreated control group. Each animal in Group V was orally treated with closantel at 10 mg/kg body weight. During the course of the study, all animals were maintained under an identical semi-intensive system of management. Compared to the untreated control group (Group IV), there was no conspicuous reduction in post-treatment (day 10) faecal egg counts (FEC) in animals administered with the herbal extracts (Groups I, II and III), which is suggestive of poor anti-parasitic activity. However, using the faecal egg count reduction test (FECRT), the overall efficacy of closantel was recorded as 95.64%. This supports the rotational use of closantel as a preferred choice over the benzimidazole group of anthelmintics and/or herbal extracts to meet the acute challenge of in situ development of drug-resistant gastrointestinal nematodes, especially Haemonchus contortus.

Evaluation of dipstick-ELISA using 28 kDa Fasciola gigantica cathepsin l cysteine proteinase (FgCL3) for serodiagnosis of fasciolosis in naturally infected goats.

In the present investigation 100 goats presented for slaughter were used to evaluate the 28kDa cathepsin l cysteine proteinase (FgCL3) dipstick-ELISA for the diagnosis of fasciolosis. Presence of Fasciola gigantica worms in liver at the time of slaughter was taken as a gold standard for the evaluation of the assay. Faeces, blood and liver were taken from all slaughtered goats. Biochemical parameters and coprological examinations using sedimentation technique were also taken into consideration. Total serum proteins, albumin, mean values of aspartate aminotransferase and alkaline phosphatase of positive group were not significantly different from those of the negative group. The diagnostic sensitivity of dipstick-ELISA was higher than coprological detection of fluke eggs. However, specificity was equal for both the tests. The accuracy of dipstick-ELISA in detecting circulatory antibodies during the course of disease was higher than coproscopic examination. In conclusion, the FgCL3 antigen dependent dipstick-ELISA was more reliable and has better scope for field application in the endemic areas.

Immunodiagnostic/protective role of cathepsin L cysteine proteinases secreted by Fasciola species.

Cathepsin L, a major cysteine proteinase secreted by the parasite plays a pivotal role in various aspects of its pathogenecity. The enzyme takes part in nutrient acquisition by catabolizing host proteins to absorbable peptides, facilitates the migration of the parasite through the host intestine and liver by cleaving interstitial matrix proteins such as fibronectin, laminin and native collagen and is implicated in the inactivation of host immune defenses by cleaving immunoglobulins. Recently, Cathepsin L has been shown to suppress Th1 immune response in infected laboratory animals making them susceptible to concurrent bacterial infections. Accordingly, the protease has been recognized as an important target at which parasite intervention strategies should be directed. Fluke Cathepsin L cysteine proteinases are also reported as sensitive and specific markers for the immunodiagnosis of fasciolosis in ruminants. Further, vaccination of laboratory or large animals with these proteases resulted in a significant reduction in fluke burden and/or fecundity.

Role of excretory-secretory metabolites of Fasciola gigantica in modulating delayed-type hypersensitivity in rats.

The role of excretory-secretory metabolites of Fasciola gigantica in modulating the delayed type of hypersensitivity in the host (rats) was investigated. Eighteen rats of either sex, aged 3-4 months, were assigned to three groups of 6 animals each. Rats in group 1 served as non-inoculated controls and each rat in this group was administered only Freund's complete adjuvant on day 7. Animals in groups 2 and 3 were administered inoculation dose(s) of somatic F gigantica antigen (SFgA) and excretory-secretory F gigantica antigens (ESFgA) according to the experimental schedule. The delayed-type hypersensitivity was monitored by assessing alterations in the foot pad thickness, its histopathology and lymphocyte proliferation assay. It was observed that the ESFgA caused diminution in delayed-type hypersensitivity response to a significant level (p <0.01) against SFgA in rats. This finding was further confirmed by lower stimulation indices of peripheral blood mononuclear cell in rats sensitized with ESFgA prior to inoculation of SFgA (group 1) than in nonsensitized rats receiving only SFgA (group 2).

Detection of circulating 54 kDa antigen in sera of bovine calves experimentally infected with F. gigantica.

The antibody response and circulating antigen levels in bovine calves, infected experimentally with Fasciola gigantica, were monitored using enzyme-linked immunoelectrotransfer blot (EITB) and sandwich ELISA, respectively. By EITB, the infected calves' sera recognized the polypeptides in the range of 54-58 kDa as early as 2 weeks post-infection. By 12th week post-infection, the lower two polypeptides of 12 and 8 kDa had disappeared. In sandwich ELISA, the circulating 54 kDa and whole worm antigen of F. gigantica were detected in the sera samples of infected calves as early as 2 weeks post-infection and persisted until the end of experiment (26th week PI). The 54 kDa antigen of F. gigantica appears to be specific and possesses promising immunodiagnostic potential for early prepatent diagnosis of bovine fasciolosis.

28 kDa Fasciola gigantica cysteine proteinase in the diagnosis of prepatent ovine fasciolosis.

Coprological confirmation of ovine fasciolosis in the field, prior to out breaks of the disease and/or strategic antifluke medication, seem to be of little consequence. Efforts are, therefore, being made to evolve a putative antigen specific to serodiagnostic test for early diagnosis during prepatency. In the present investigation, 28 kDa cysteine proteinase was used in ELI SA and Western blot to detect Fasciola gigantica antibodies and further Dipstick-ELISA was developed for field application, using known positive monospecific sera from experimentally infected sheep with 100 F. gigantica metacercariae. Isolation of 28 kDa cysteine proteinase was achieved from bubalian origin flukes. The specific antigen, recognised homologous antifluke antibodies by Western blot as early as 2nd week post-infection (wpi) with 100% sensitivity, in sera samples of sheep harbouring 38 flukes and by 10th wpi in sheep harbouring 3-8 flukes. All sheep were found positive for the infection when ELISA and/or Dipstick-ELISA was applied from 4th wpi. In pooled sera of infected sheep, these were positive during 4th wpi.

Parasitic infections of Indian yak Bos (poephagus) grunniens--an overview.

For centuries, the yak and its hybrids with domestic cows (dzomo/dzo) have been contributing to the socio-economic status of their owners in desolate regions of the Greater Himalayas. Studies on the prevalence of parasitic diseases in these animals were undertaken in Ladakh (Jammu and Kashmir), Sikkim and villages near the Indo-Nepal border of Uttar Pradesh. Visceral organs of necropsied animals were observed for the presence of adult metazoan parasites, fresh or preserved faecal samples were examined for the eggs of helminth parasites and protozoan cysts, and blood smears were examined for haemo-protozoa and microfilariae. In all, examination of 225 faecal samples, 180 blood smears and the visceral organs of thirteen yaks and dzomo/dzo was undertaken. On necropsy, visceral organs revealed various adult liver and stomach flukes, gastrointestinal nematodes, tapeworms, cysts of Coenurus spp. and hydatid cysts, as well as Setaria cervi worms and large and/or small sized Sarcocystis cysts. On coprological examination, egg prevalences of 10% for Fasciola spp., 6.6% for various amphistomes, 10% for Moniezia spp., 76.4% for Strongylate spp., 24% for Neoascaris spp. and 13.7% for Nematodirus spp. were recorded. Identification of infective larvae from the faecal cultures showed that a majority of eggs (86.3%) in the host faeces were contributed by nematodes belonging to Trichostrongyle spp., Ostertagia spp. and Cooperia spp. This was followed by Chabertia spp. (6.5%). Haemonchus spp., Bunostomum spp. and Nematodirus spp. together contributed only 7.2% of the eggs found. Among protozoan infections, Eimeria brasiliensis and E. zurnii were common. None of the blood smears evidenced any haemoprotozoa or microfilariae. Likewise, none of the animals were positive for Trichuris spp.(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous determination of beryllium and aluminium in mixtures using derivative spectrophotometry.

The spectrophotometric determination of beryllium and aluminium with 5,8-dihydroxy-1,4-naphthoquinone in the presence of a non-ionic surfactant is reported. Absorption maxima, molar absorptivity and Sandell's Sensitivity of 1:2 (M:L) beryllium and aluminium complexes are, 585 nm and 598 nm, 1.63 x 10(4) l.mole(-1).cm(-1) and 2.04 x 10(4) l.mole(-1).cm(-1), and 0.55 ng/cm(2) and 1.32 ng/cm(2) respectively. Beer's law is obeyed between 7.20-3.96 x 10(2) ng/ml beryllium and 1.08 x 10(1)-1.08 x 10(3) ng/ml aluminium. A method for simultaneous determination of beryllium and aluminium in their mixture using derivative spectra is described. The range 3.6 x 10(1)-3.6 x 10(2) ng/ml beryllium could be determined in the presence of 1.08 x 10(2)-1.08 x 10(3) ng/ml aluminium, and vice versa.

Immunization with irradiated larvae against Dictyocaulus filaria in young lambs.

In the lungworm-endemic areas of Kashmir, 6-10 week old lambs of Karnah and Kashmir Merino breeds were vaccinated with two doses of 50 kR gamma-irradiated larvae of Dictyocaulus filaria, given a month apart. Assessed on the basis of reduced prevalence and significantly lower faecal larval output over an eight-month observation period, vaccinated lambs showed a high degree of resistance to naturally acquired D. filaria infection. The results also show that vaccination against D. filaria provided some degree of protection against infection with other lungworm species.

Immunization of lambs against Oesophagostomum columbianum, using irradiated third stage larvae.

The effect of gamma irradiation at doses of 40- and 50 kR on the development of third stage larvae of Oesophagostomum columbianum and the protection conferred by these irradiated larvae against the nematode, was studied in 6-8 week old male Kashmir Merino lambs. At 40- and 50 kR doses, the third stage larvae failed to develop to the adult stage in the intestine. Though single vaccination with 2000, 50 kR irradiated larvae failed to protect the animals against the infection, vaccination with the same number of 40 kR irradiated larvae conferred a partial protection. The presence of adult worms of O. columbianum in sites outside the intestine of 6-8 week old lambs have been demonstrated for the first time.