Precipitins in Sera of Swine Infected with Stephanurus dentatus

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Precipitins for antigens in a whole-worm extract of Stephanurus dentatus were detected at various times during the prepatent period in sera from 16 of 17 swine exposed to experimental infection with this nematode. Precipitation patterns visualized by a micro-Ouchterlony method were distinguishable from those seen with sera from helminth-free swine or from swine infected with other nematodes. In its present form, however, the number of samples required for some degree of confidence in the procedure as a diagnostic test would be prohibitive under field conditions. Tromba and Baisden (1960) reported that exlayer of tap water. After 7 to 10 days at 70 F, perimental kidney worm disease in swine could the infective larvae were recovered in a Baermann apparatus and used immediately to infect swine be diagnosed during certain periods of prey oral administration of larval of various ages by oral administration of larval patency by an agar diffusion technique using suspension in tap water. The number of larvae whole-worm antigen. Since then, we have given was estimated by dilution count except that applied this technique to determine the inwhen doses of 30 larvae were used actual counts in were made. A schedule of infections is given in ception and duration of specific precipitins in Table I and Text Figure 1. Blood samples were the blood of other groups of experimentally obtained from these experimentally infected aniinfected swine. Data from these experiments mals at weekly or irregular intervals. are presented with a critical evaluation of Sera from 54 swine exposed to natural infection with kidney worm were obtained from two groups the technique as a field diagnostic test for in a program for management control at Tifton, stephanuriasis. Georgia, similar to that described by Stewart and Tromba (1957). Group 1 consisted of 36 swine MATERIALS AND METHODS farrowed in the fall of 1959 on pastures which had Ova of Stephanurus dentatus were recovered been contaminated with kidney worm eggs from from urine by filtration and cultured in a shallow patent sows for several months prior to April 1959, but not thereafter. Sera were obtained once just Received for publication 29 September 1961. before marketing in February 1960. Group 2 conTABLE I. Necropsy results of swine infected with single or multiple doses of kidney worm larvae at different ages. Age (weeks) Pig number Infections Necropsy findings Necreopsy 1st 2nd 3rd Liver fibrosis Perirenal area1 72 8 42 50 Moderate Juveniles 58 10 44 76 Moderate Juveniles and adults 57 10 44 51 76 Severe Juveniles and adults 56 10 44 51 76 Severe Juveniles and adults 34 52 80 Severe2 Negative 81 11 23 45 None3 Negative 90 11 46 None Juveniles and adults 83 11 23 45 Slight Juveniles and adults 84 11 23 45 Slight Juveniles and adults 85 11 45 Slight Juveniles and adults 86 11 23 46 Slight2 Negative 87 11 23 44 Moderate Juveniles and adults 88 11 28 Severe Juveniles 89 23 40 Moderate2 Negative 49 16 17 40 Moderate Juveniles 48 16 40 Moderate Juveniles 46 16 17 40 Moderate Juveniles 50 40 Negative Negative 1 Includes kidneys, iureters, surrounding fat, and psoas muscles. 2 Larval forms in liver. 3 No worms found in liver. 633 This content downloaded from 157.55.39.104 on Mon, 20 Jun 2016 05:58:34 UTC All use subject to http://about.jstor.org/terms THE JOURNAL OF PARASITOLOGY