Glutathione-S-transferase: an important diagnostic antigen of liver amphistome Gigantocotyle explanatum, infecting the Indian water buffalo

The foodborne trematodiases pose a significant health problem to the animals as well as the human population living in close proximities with the livestock and are still considered as the neglected tropical diseases by the World Health Organisation. The digenetic trematode, Gigantocotyle explanatum infecting the liver of Indian water buffalo, Bubalus bubalis, has been identified as one of the most common helminth parasite responsible for the disease, amphistomosis, in livestock. Despite huge abattoir prevalence, the epidemiological data and the actual economic losses incurred due to this parasite alone are yet to be established probably due to the limitations of routinely used diagnostic tests. The gold standard for the confirmation of such infections under field conditions is still the fecal egg count (FEC). However, the poor sensitivity and cumbersome nature of these tests necessitates the development of a more sensitive, reliable and easy to perform workflow/method. Immunological diagnosis of helminthic infections is still considered as an alternative to the FEC. Therefore, efforts have been made to utilize glutathione-S-transferase (GST), a vitally significant molecule of the adult G. explanatum, for the serodiagnosis of amphistomosis under both laboratory and field conditions. The GST antigen was first affinity purified from the somatic extract of the adult worms since its highest level was recorded in the somatic extracts followed by eggs and the excretory/secretory products. A five-fold affinity purified native GST antigen of about 25 kDa was found to be highly immunogenic as evident from high titre (1:25,600) of the polyclonal antibodies raised in the rabbits. The immunoblotting results revealed differential presence of GST in the adult worms, their eggs and excretory/secretory products. The immunolocalization studies revealed that the vitelline glands are the major source of GST in liver amphistome. Further, we were able to successfully screen animals naturally infected with G. explanatum using anti GST polyclonal antibodies in dot blot assay. High levels of both circulating GST antigen and anti GST antibodies were detected in the serum of the animals naturally infected with G. explanatum, while no cross reactivity was observed with the tropical liver fluke, F. gigantica which often infects the buffalo liver concurrently. The findings of the present study indicate that GST could be used as an important antigen for the diagnosis of G. explanatum infection in Indian water buffaloes.

In vitro effect of metrifonate on the indices of oxidative stress in Gigantocotyle explanatum

Helminth infections in general and digenetic trematodes in particular cause a huge economic loss globally to our livestock. Gigantocotyle explanatum is a digenetic amphistome that infects the bile ducts of water buffalo and are highly prevalent in tropical and sub-tropical countries. In the present study, effects of an organophosphate compound, Metrifonate (MF) in three doses, viz., 9.4 × 10^-5 M (Dose I), 14.4 × 10^-5 M (Dose II), and 19.4 × 10^-5 M (Dose III), have been studied in vitro, on the motility and on some enzymatic and non-enzymatic oxidative stress indices in G. explanatum. The worm's motility and their non-enzymatic oxidative stress biomarkers like lipid peroxides measured as thiobarbituric acid-reactive substances (TBARS) and reduced glutathione (GSH) were disrupted significantly in a dose-dependent manner. However, the enzymatic oxidative stress biomarkers like glutathione-S-transferase (GST) and superoxide dismutase (SOD) were affected by MF treatment in a biphasic manner. Exposure to Dose I significantly stimulated the activities of both GST and SOD, whereas exposure to Doses II and III resulted into significant inhibition in a dose-dependent manner. Our findings suggest that MF has potential to be a strong and effective anthelmintic, however, further studies in vitro as well as in vivo are needed to explore further these observations and understand the exact mode of MF action in G. explanatum and other trematodes of veterinary economic importance.

First record of a rare transversotrematid cercaria larva (Trematoda: Digenea) from Rajasthan, India: focus on seasonal occurrence and host-specificity of diverse cercariae

During the survey of freshwater snail hosts and their digenean larval trematode parasites, a rare cercaria larva belonging to family Transversotrematidae and subclass Digenea (Trematoda) was recovered from the snail species Melanoides striatella tuberculata inhabiting perennial Som river of Udaipur district, Rajasthan, India. More than 28 % mature specimens of these snails were found to be infected with transversotrematid cercaria larvae in the spring season. Body of this cercaria is large, bowl-shaped, biocellate, spinose, transparent and laterally extended having two pigmented eye spots, two hold fast organs extended from the junction of body and tail, large tail with two foliated furcal rami, and cyclocoel intestinal caeca. As far as the authors are aware, this is the first record of a transversotrematid larva from Rajasthan, India. Simultaneously, other forms of cercariae viz., amphistome, echinostome, monostome, gymnocephalous, furcocercous and xiphidiocercous cercariae were also recovered from fifteen species of pulmonate and operculate snails including Lymnaea acuminata f. patula, L. acuminata f. chlamys, L. acuminata f. typica, L. acuminata f. rufescens, L. luteola f. australis, L. luteola f. typica, L. luteola f. impura, Planorbis (Indoplanorbis) exustus, and Anisus (Gyraulus) convexiusculus, Faunus ater, Melania (Plotia) scabra, Thiara (Tarebia) lineata, Melanoides striatella tuberculata, Vivipara bengalensis race gigantica and V. bengalensis race mandiensis. The seasonal occurrence and host-specificity of diverse trematode cercaria larvae are also discussed besides the first record of a rare transversotrematid cercaria larva from Rajasthan, India.

Amphistome species in cattle in South coast of caspian sea

BACKGROUND

Knowledge about the amphistomid fauna in Iranian domestic ruminants depends on the studies conducted almost 30 years ago. The last situation in cattle is introduced here in the provinces in south coast of Caspian Sea.

METHODS

Amphistomid species were collected from cattle at slaughter houses of the provinces Gilan and Mazanderan in 2010. Median sagittal sections were prepared by the conventional method. Species were identified by the histomorphological pecularities of the muscular argans.

RESULTS

Five amphistomid species, Paramphistomum cevri, P. gotoi, Calicophoron calicophorum, Carmyerius spatiosus and Gastrothylax compressus, recovered. Calicophoron calicophorum is a new species for Iran. Criteria used in identification of the species were illustrated.

CONCLUSION

Iran has a rich amphistomid fauna and mostly under the influence of oriental conditions.