Pergamon Inrernariona/ Journnljor Poranro/ogy, Vol. 27, No. I I, pp. 1429-1432, 1997 0 1997 Austrahan Society for Parasitology Published by Elsevier Science Ltd Printed in Great Britain PII: SOO20-7519(97)00090-S lM2&7519/97 $17.00+0.00 RESEARCH NOTE Immunodiagnosis of Fasciolosis in Horses and Pigs Using Western Blots TEXIA GORMAN,* JIMENA ABALLAY, FERNANDO FREDES, MARCO SILVA, JUAN CARLOS AGUILLbN and HECTOR A. ALCAiN Preventive Veterinary Medicine Department, Veterinary Sciences Faculty, University of Chile, Casilla 2, Correo 1.5, Santiago, Chile (Received 2 May 1997; accepted IO July 1997) Abstract-Gorman T., Aballay J., Fredes F., Silva M., Aguilldn J. C. & Alcaiuo H. A. 1997. Immunodiagnosis of fasciolosis in horses and pigs using Western blots. International Journalfir Parasitology 27: 14291432. Crude and partially purified somatic (S) and excretorysecretory (ES) antigens of Fasciola hepatica were subjected to Western blot analysis in order to identify polypeptides that would enable specitic and sensitive immunodiagnosis of horse and pig fasciolosis to be undertaken. Sera from 20 horses and 20 pigs with natural infections of F. hepatica and the same number of uninfected hosts of each species were tested, together with sera from 2 pigs with Cysticercus cellufosae infections. Using crude S antigens, sera from infected horses and pigs reacted specifically with a wide range of polypeptides of 14-19, 22-30, 35-37 and 42kDa. Likewise, specific reactivity between polypeptides of 14-17, 22-30 and 4&42 kDa in crude ES antigens and sera from infected horses and pigs was obtained. Against the criteria of high sensitivity and speciticity, the 22-30-kDa polypeptides would appear to be the most suitable candidate antigens for use in the immunodiagnosis of fasciolosis in horses and pigs. 0 1997 Australian Society for Parasitology. Published by Elsevier Science Ltd. Key words: Fasciolosis; equine fasciolosis; swine fasciolosis; immunodiagnosis; Fusciola hepatica; antigens: Western blot. Fasciolosis. caused by Fasciola hepatica and F. gigan- tica, has a worldwide distribution and causes sig- nificant economic losses among domesticated animals due to decreased productivity, mortality and liver con- demnation. In some regions of Chile, the rate for bovine liver condemnation at slaughter houses is as high as 80% (Alcaino et al., 1992). and many human cases of fasciolosis have been reported in Latin Amer- ica (Apt et al., 1988; Hillyer et al., 1992). Diagnosis of infection is routinely based on finding the fluke eggs in faeces by coprological examination. However. this method is not sensitive, and infections where the parasite burden is low or when the host is harboring immature flukes in the liver parenchyma or the bile ducts during the prepatent phase of the infec- tion may go undetected. Furthermore, the copro- logical method sometimes fails to detect all infections, *To whom correspondence should be addressed. Fax: (56-2) 541 6840; E-mail: tgorman@abello.dic.uchile.cl. and some cases are classed as false negatives (Gorman et al., 1991). Moreover, in some species such as horses, an intermittent fluke egg elimination has been described (Owen, 1977). For these reasons a more effective diagnostic method is needed and immuno- logical methods can provide a possible solution. However, it has to be noted that a possible drawback of such methods is that a positive result does not necessarily discriminate between a prior infection and a current one, and some caution needs to be exercised in interpreting the results. Numerous immunological methods have been applied to the immunodiagnosis of fasciolosis, and enzyme-linked immunosorbent assay (ELBA), in par- ticular, has shown adequate sensitivity and specificity for this purpose (Zimmerman et al., 1982; Itagaki et al., 1989). However, the complex nature of antigenic preparations used in such methods can lead to prob- lems of cross reactivity, indicating the need for more purified antigen fractions. Furthermore, there is lack of information regarding fasciolosis in some animal 1429