THE PRODUCTION OF A SPECIFIC ANTISERUM TO BIRD SERUM*

A specific method is needed for the identi fication of avian bloods from unknown sources. Attention has been drawn to this problem by the recognition that birds are the natural hosts of a large number of mosquito-borne viruses. ' How ever, the lack of a technique for studying the frequency of mosquito feedings on proven and suspected avian hosts has delayed essential field epidemiological studies. The classical ap proach to this problem would be to identify, with specific precipitating antisera, blood sam pies from the stomachs of known and suspected vectors collected in the field. Precipitating anti sera produced in rabbits have been unsatisfac tory as they reacted similarly to the serum proteins of all bird species. Arthropod blood meals could only be tested for the presence or absence of bird blood.2 @ A single study has been reported in which more specific avian anti sera were developed.4 Culex tarsalis, a primary vector of Western equine and St. Louis en cephalitis viruses, was found to have fed on both domestic and wild birds. Epizootiological studies of avian mai@ia61 and exposure of a variety of birds in mosquito bait traps have confirmed the frequency of vector attack on birds.7'8 However, all such approaches were indirect and did not provide a satisfactory measure of host preferences, and did not yield quantitative data suitable for epidemiological analysis. Over a period of years, acceptable testing procedures have been developed for the identification of mammalian bloods.9 The ob jective of this study has been to develop equally satisfactory precipitating antisera for applica tiontoepidemiologicaland phylogeneticstudies of birds. The chicken was chosen for a study of the production of antibody to bird serum proteins. This animal seemed ideally suited for the pur pose for the following reasons: it has been used extensively in precipitin work; it is an excellent * This investilation was supported in part by a researchgrant(E3028C-2)fromtheNationalInst