Standardization and application of indirect plate ELISA for immunodiagnosis of paramphistomosis in ruminants

Isolation and immunoblotting of somatic antigens of Cotylophoron cotylophorum and Gastrothylax crumenifer

Paramphistomosis is the emerging fluke infection in young ruminants which results in high morbidity and mortality in tropics and sub-tropics. The present study was carried out to detect the sharing antigens among the purified somatic antigens of G. crumenifer and C. cotylophorum, in  order to use as a candidate antigen for diagnosis of paramphistomosis in sheep. Immunoblot analysis of the purified somatic antigens of C. cotylophorum and G. crumenifer using their specific rabbit hyper immune serum revealed 3 common polypeptides at the range of 27, 29 and 60 kDa. Hence these three immunodominant peptides can be used candidate antigens in development of vaccines against ovine paraphistomosis and also for early diagnosis of infection.

Amphistomes

Amphistomes, commonly referred to as 'stomach' or 'rumen' flukes because of the localization of these flukes in the stomach of ruminants, are digenetic trematodes distinguished by the absence of an oral sucker and the position of the ventral sucker or acetabulum at the posterior end of the body. The body is characterized by leaf-like fleshy structure, pink or red in colour with a large posterior sucker. Amphistomes are an important group of parasites since they cause 'amphistomiasis' (variously known as paramphistomosis/amphistomosis), a serious disease of great economic importance in ruminants worldwide. These parasites have a broad spectrum of definitive hosts together with a wide geographical distribution. Though, they form a continuous evolutional lineage from fishes to mammals, amphistomes mainly inhabit the rumen and reticulum of ruminant mammals, while some species occur in the large intestine or parenteric sites of ruminants, pigs, equines and man.

Amphistome infections in domestic and wild ruminants in East and Southern Africa: A review

In this article, the main amphistome species infecting domestic and wild ruminants in East and Southern Africa, their snail intermediate hosts and epidemiological features are reviewed and discussed. Twenty-six amphistome species belonging to nine genera from three families occur in domestic and wild ruminants in the region under review and over 70% of them belong to the genera Calicophoron, Carmyerius and Cotylophoron. Of the amphistome species, 76.9% are shared between domestic and wild ruminant hosts – an important observation when considering the different options for control. Seven freshwater snail species belonging to four genera from two families act as intermediate hosts of the identified amphistome species, with the genus Bulinus contributing 57% of the snail species. Some of the snails are intermediate hosts of amphistome species belonging to the same genus or to different genera; a phenomenon not yet fully elucidated as some snails are reported to be naturally infected with amphistome cercariae of unidentified species. Only nine (34.6%, 9/26) of the amphistome species have known snail intermediate hosts, while most (65.4%, 17/26) have unknown hosts. Species of intermediate hosts and the potential of the flukes to infect these hosts, the biological potential of the snail hosts, the definitive hosts management systems and their grazing habits are considered to be the main factors influencing the epidemiology of amphistomosis. Based on the epidemiological features of amphistome infections, various practical control options are discussed. Further research is necessary to determine amphistome–snail associations, develop diagnostic tests that can detect prepatent infections in the definitive host, determine the burden and economic importance of amphistomosis in domestic and wild ruminants and the efficacy of different anthelmintics in the treatment of patent infections.

Identification of immunodominant fraction of Paramphistomum epiclitum and its evaluation for use in the serodiagnosis of paramphistomosis by ELISA

The present study was undertaken to identify and purify the immunodominant fractions from the excretorysecretory (ES) antigen of Paramphistomum epiclitum, a predominant amphistome species infecting ruminants inIndia. ES antigen was prepared and characterized using SDS-PAGE and Western blot analysis. Major polypeptidesof molecular weight 11, 22, 28, 31, 33, 39, 52, 59, 63 and 72 kDa were visualized in SDS-PAGE. Polypeptides (9)of 11, 14, 16, 22, 31, 33, 39, 63 and 72 kDa showed immunoreactivity in Western blot analysis. The whole ESantigen of P. epiclitum was initially concentrated using PEG-8000 followed by spin-X UF concentrator with 10kDa cutoff range and subsequently fractionated by size exclusion chromatography using Sephadex G-25. Crossreactivity of the P. epiclitum ES antigen was studied with positive sera of F. gigantica and H. contortus. Based onthe cross reactivity profile, the low molecular weight antigenic fraction with 11 kDa polypeptide was selected forfurther use in indirect-ELISA. Bovine serum samples (258) were tested with optimized ELISA. Sensitivity of theELISA was calculated as 75.0%, while the specificity was 85.0%. The percent positive and negative predictivevalues for the test were 70.78 and 87.57%, respectively.

Incidence of amphistome infection in sheep from Mhow, Madhya Pradesh

A total of 445 faecal samples and 128 rumens of sheep collected from Slaughter house, Mhow (Madhya Pradesh) were examined for a period of 1 year from February 2011 to January 2012. Faecal sample examination based, incidence of amphistomes was found to be 23.37% from the study area. The incidence of amphistomes was significantly higher (p < 0.01) during summer (36.75%) than winter (27.74%) and monsoon (3.52%). Age-wise, non-significantly higher infection was observed in ≥1 year-old animals (23.61%) than <1 year-old animals (23.11%). Non-significantly higher rate of infection was recorded in case of females (25.63%) than that of males (19.64%). Out of 128, 49 (38.28%) rumens were found positive for amphistomes. The prevalence of Paramphistomum cervi (27.34%) was found to be significantly (p < 0.01) higher than Gastrothylax crumenifer (10.94%).