All 37 fetuses of 3 laparotomized pregnant sows at 86, 92, and 93 days of gestation were inoculated intramuscularly through the uterine wall with porcine circovirus type 2 (PCV-2). The sows were allowed to farrow, and blood and tissue samples were collected from their piglets before and after suckling colostrum. Thirteen fetuses from 2 sows at 90 and 103 days of gestation were used as controls. Of the 37 PCV-2 inoculated fetuses, 24 were grossly normal and 13 were mummified, stillborn, or weak-born at farrowing. Infection with PCV-2 was demonstrated in various tissues of grossly normal and abnormal fetuses by virus isolation, polymerase chain reaction, and immunohistochemical methods. Antibodies specific to PCV-2 were also detected from the sera or thoracic fluids of abnormal fetuses and unsuckled normal pigs. No evidence of PCV-2 infection was found in any control fetuses. The present results confirm previous findings that PCV-2 can infect late-term swine fetuses and may cause reproductive abnormalities.
Abstract. An immunoperoxidase monolayer assay (IPMA) has been developed to detect antibodies against swine influenza A virus (SIV) in pig sera. The test was evaluated by using sequential sera from pigs experimentally infected with H1N1 subtype of SIV. Two hundred field serum samples that had been examined by the hemagglutination inhibition (HI) test were also tested. Antibodies specific to SIV were detected as early as 3 days postinoculation (dpi) in the IPMA test as compared with 7 dpi by the HI test. Unlike HI, no serum treatment was required in the IPMA test. Regardless of the virus used in the test, IPMA detected antibodies to both H1N1 and H3N2 subtypes of SIV whereas HI detects antibodies against either H1N1 or H3N2, depending upon the virus used in the test. Results of this study indicate that IPMA is a useful test for screening of pig sera for SIV antibodies.Swine influenza virus (SIV) belongs to the family Orthomyxoviridae. 4 There are three types of this virus based on the antigenic relatedness of nucleoprotein (NP) and matrix (M) proteins: A, B, and C. 12 Most of the swine influenza worldwide is caused by type A, 6 which is further divided into subtypes on the basis of its hemagglutinin (HA) and neuraminidase (N) surface proteins. The predominant subtypes reported to be associated with swine influenza throughout the world are H1N1, H1N2, and H3N2. 1,19 H1N1 has been the predominant subtype circulating in pigs in the United States. 2,5,14 Recently, however, H3N2 has been recovered from swine with acute clinical disease in the eastern and north central regions of the United States. 8,18,21,22 Subtype H1N2 has also been isolated recently from pigs in Indiana. 7 Serological diagnosis of SIV is currently based on hemagglutination inhibition (HI) tests. Since there is no crossreaction between hemagglutinins, 2 different HI tests are used to detect antibodies against H1N1 and H3N2 subtypes of SIV. A serological test that can detect anti-NP antibody would be useful in diagnosing infection with all type A influenza viruses because NP protein is relatively conserved among various SIV strains. 19 Sensitive enzyme-linked immunosorbent assays (ELISA) have also been developed for SIV. 11,16,20 However, substantial amounts of purified antigens 15 or recombinant protein are needed for coating ELISA plates. 16,20 The purpose of this study was to develop an immunoperoxidase monolayer assay (IPMA) for the detection of SIV type A antibodies and compare it to the HI tests.Two subtypes of SIV (H1N1 and H3N2) were used in both IPMA and HI tests. A/Sw/NJ/1979/H1N1 was obtained from the National Veterinary Services Laboratories, Ames, Iowa, and A/Sw/MN/1998/H3N2 was isolated from a field sample submitted to the Minnesota Veterinary Diagnostic Laboratory (MDVL). A field isolate, A/Sw/MN/1997/H1N1, recovered from a grower pig in Minnesota was used for ex- perimental infection of pigs. Each isolate was confirmed to be H1-or H3-type by previously described method. 9 Experimental sera were produced in 5-week-old pigs. Eleven pigs ...
Indigenous Lactobacilli are suitable probiotics because they adapt well in the hosts and ecological niches. Here we test local Lactobacillus for future application in the pigs as the farm-autogenous strains. The objectives of this study were to evaluate the probiotic properties of Lactobacillus isolated from the feces of antibiotic-free organic pigs. The properties include bile salt and pepsin tolerance, survival in storage (37 & 4 o C) and probiotic-packaging (50 o C) temperatures, antibiogram, and antagonistic activity against Salmonella typhimurium ATCC 13311 and Escherichia coli ATCC 25922. Eighteen isolates with three different species were tested in this study as follows: L. reuteri (seven strains), L. mucosae (ten strains), and L. plantarum (one strain). Four isolates-L. reuteri-OP1, L. mucosae-OP2, L. mucosae-OP3, and L. reuteri-OP17-had good in vitro probiotic characteristics. Eleven isolates completely inhibited both E. coli and S. typhimurium. The other isolates are perfectly disabled, either E. coli or S. typhimurium. Despite that, they caused a reduction in the numbers of each pathogen. All Lactobacilli tested were susceptible to amoxicillin-clavulanate, ampicillin, and imipenem. Most isolates were sensitive to clindamycin (72%), gentamicin (56%), and tetracycline (50%). Half of the proportions were somewhat sensitive/resistant to cefotaxime (39/44%), tetracycline (50/39%), and streptomycin (39/56%). One hundred percent of Lactobacilli were resistant to norfloxacin, sulfamethoxazole-trimethoprim, and vancomycin, while 94% were resistant to enrofloxacin. Most of the local Lactobacilli passed in vitro tests, but the efficacy of probiotics in pigs awaits further in vivo investigation. Therefore, the potential probiotic strains derived from this study could be selected for further evaluation of their probiotic roles in economic pigs.
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