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PubMed2007

Serologic surveillance of swine H1 and H3 and avian H5 and H9 influenza A virus infections in swine population in Korea.

Influenza A is a respiratory disease common in the swine industry. Three subtypes, H1N1, H1N2 and H3N2 influenza A viruses, are currently co-circulating in swine populations in Korea. An outbreak of the highly pathogenic avian influenza H5N1 virus occurred in domestic bird farms in Korea during the winter season of 2003. Pigs can serve as hosts for avian influenza viruses, enabling passage of the virus to other mammals and recombination of mammalian and avian influenza viruses, which are more readily transmissible to humans. This study reports the current seroprevalence of swine H1 and H3 influenza in swine populations in Korea by hemagglutination inhibition (HI) assay. We also investigated whether avian H5 and H9 influenza transmission occurred in pigs from Korea using both the HI and neutralization (NT) tests. 51.2% (380/742) of serum samples tested were positive against the swine H1 virus and 43.7% (324/742) were positive against the swine H3 virus by HI assay. The incidence of seropositivity against both the swine H1 virus and the swine H3 virus was 25.3% (188/742). On the other hand, none of the samples tested showed seropositivity against either the avian H5 virus or the avian H9 virus by the HI and NT tests. Therefore, we report the high current seroprevalence and co-infectivity of swine H1 and H3 influenza viruses in swine populations and the lack of seroepidemiological evidence of avian H5 and H9 influenza transmission to Korean pigs.

Animals↗
PubMed2002

Use of a swine bioassay and a RT-PCR assay to assess the risk of transmission of swine hepatitis E virus in pigs.

The objective of this study was to assess the risk of transmission of swine hepatitis E virus (swine HEV) to naïve pigs by inoculation with tissues or feces collected from pigs infected experimentally with swine HEV. Seventy-five, 3-week-old pigs were assigned randomly to 24 groups of 3-4 pigs and inoculated with homogenates of tissues (liver, heart, pancreas, or skeletal muscle) or a suspension of feces from swine HEV-infected pigs collected at 3, 7, 14, 20, 27, or 55 days post inoculation (DPI). Each inoculum was prepared as a 10% suspension (w/v) in PBS buffer and tested by a semi-quantitative RT-PCR for swine HEV RNA and by the swine bioassay. The inoculation route was intravenous for liver, heart and pancreas, and via stomach tube for skeletal muscle and fecal suspension. The liver homogenate inocula and feces collected at 3-7 and 14-20 DPI were positive for swine HEV RNA by RT-PCR. The pigs inoculated with liver homogenates collected at 3-7 and 14-20 DPI developed anti-HEV antibodies and swine HEV RNA was detected in their sera. Pigs inoculated with heart, pancreas, skeletal muscle homogenates or fecal suspensions failed to develop anti-HEV antibodies. These findings suggest that there is a potential risk of transmission of swine HEV via liver tissue from infected pigs in the early stages (3-20 DPI) of infection and the in vitro RT-PCR assay correlates well with the swine bioassay.

Animals↗
PubMed1977

[Disposal of aerobic treated swine waste by refeeding to finishing swine (author's transl)].

Simple aerobic treatment of swine waste did not increase the production of microorganismprotein (pure protein). Addition of available energy resulted in a small increase of pure protein: During continuous aerobic treatment 20 g pure protein were produced by 100 g starch, during discontinuous aerobic treatment 10 g pure protein by 100 g organic matter from molasses (mean values). Comparative feeding trials with 90% resp. 80% feed restricted finishing swine without and with added swine waste (continuous treated without supplements resp. discontinuous treated with addition of yeasts and molasses) had as results no improvement in body-weight-gain but a 12% resp. 17% deterioration in feed conversion with 13% less bodyfat formation. Weight gains of both groups with restricted feed (without and with added swine waste) was 22% less in comparison to full fed swine. Losses at slaughter of swine in the group with feed restriction and added swine waste were partly due to higher intestine contents higher than that of swine with feed restriction and without added swine waste. Higher weights of livers and kidneys in swine of the "waste group" counts for a possibly higher metabolism-stress.

Aerobiosis↗
PubMed1980

Incidence of salmonellae in fecal samples of production swine and swine at slaughter plants in the United States in 1978.

Nine swine slaughter plants and 19 swine production units were randomly selected for sampling from the six highest swine-producing states representing a total of 64% of the United States swine production. Three composites of 10 fresh swine fecal samples were obtained from each slaughter plant, representing three different farm sources of swine. Two composite fecal samples were collected from two different production pens from each production unit. Samples were analyzed for salmonellae. Isolated salmonellae were biochemically and serologically identified and tested for antibiotic susceptibility and resistance transfer ability. Salmonellae were recovered from swine at seven of the nine slaughter plants and 16 of the 27 composites of slaughter swine. Of the 19 production units, 3 had swine shedding salmonellae. Resistances found included streptomycin, tetracycline, and sulfadiazine. Of the 52 total isolates tested, 71% had some level of antibiotic resistance. Only 3 of 37 resistant isolated could transfer resistance under the conditions used.

Abattoirs↗
PubMed1958

The swine lungworm as a reservoir and intermediate host for hog cholera virus. II. Attempts to demonstrate the presence of hog cholera virus in lungworms derived from swine with cholera.

Suspensions of adult lungworms, procured from swine that were outwardly healthy but derived from eggs passed by swine with hog cholera, induced this disease in a small proportion of swine into which they were injected intramuscularly. This result was achieved in both lungworm-free and lungworm-infested swine, though perhaps slightly more regularly in the lungworm-infested animals. Swine that had had an intramuscular injection of lungworm suspension and that had remained normal, developed hog cholera much more regularly following the ingestion of lungworm larvae of cholera origin than did swine not previously injected with lungworms. The findings described were markedly dependent upon season and were regularly reproducible only during the first 4 or 5 months of the year. The results presented are considered as further evidence that the swine lungworm serves as reservoir and intermediate host for hog cholera virus and that the virus is ordinarily carried by the lungworm in a masked form which must be provoked to pathogenicity by some stress before it can cause obvious disease in swine.

Animals↗
PubMed2001

Prevalence of hepatitis E virus antibodies in Canadian swine herds and identification of a novel variant of swine hepatitis E virus.

Swine hepatitis E virus is a newly identified potentially zoonotic virus from pigs of particular concern for possible direct transmission to a human xenotransplant recipient by organ transplantation. In the present study, prevalence of serum antibodies to hepatitis E virus was examined in Canadian swine herds. A total of 998 serum samples collected from 6-month-old healthy slaughter hogs were examined by enzyme immunoassay and Western blot analysis for antibodies to the recombinant open reading frame 3 (ORF3) protein of hepatitis E virus expressed in Escherichia coli. These samples represented more than 80 different swine production units from five major swine-producing provinces across Canada. From this study, 594 samples (59.4%) were found to be positive for hepatitis E virus antibody. The seroprevalence was higher in Quebec (88.8%) and Ontario (80.1%) than in Alberta and Saskatchewan (38.3%). By PCR using a pair of oligonucleotide primers deduced from the ORF2 sequence of human hepatitis E virus, a specific hepatitis E virus sequence was recovered from feces of pigs. The nucleotide sequence identity between the U.S. swine hepatitis E virus and the Canadian isolate (SK3) was only 85.8%, suggesting that genotypic variations may exist in swine hepatitis E virus in North America. Among 165 serum samples collected from humans in Saskatchewan, 2.4% were found to be positive for antibodies to the hepatitis E virus ORF3 protein. Our data indicate that hepatitis E virus is highly prevalent in commercial swine populations in Canada and support the suggestion that the swine hepatitis E virus may be an important zoonotic agent for humans.

Animals↗
PubMed2002

Serologic evidence of H1 swine Influenza virus infection in swine farm residents and employees.

We evaluated seropositivity to swine and human H1 influenza viruses in 74 swine farm owners, employees, their family members, and veterinarians in rural south-central Wisconsin, compared with 114 urban Milwaukee, Wisconsin, residents. The number of swine farm participants with positive serum hemagglutination-inhibition (HI) antibody titers > or = 40 to swine influenza viruses (17/74) was significantly higher (p<0.001) than the number of seropositive urban control samples (1/114). The geometric mean serum HI antibody titers to swine influenza viruses were also significantly higher (p<0.001) among the farm participants. Swine virus seropositivity was significantly (p<0.05) associated with being a farm owner or a farm family member, living on a farm, or entering the swine barn > or = 4 days/week. Because pigs can play a role in generating genetically novel influenza viruses, swine farmers may represent an important sentinel population to evaluate the emergence of new pandemic influenza viruses.

Adolescent↗
PubMed1976

Immunofluorescence of spirochetes with serum from swine recovered from swine dysentery using an indirect fluorescent antibody test.

Using an indirect fluorescent antibody test, immunofluorescence of large spirochetes was observed with serum from swine that had recovered from swine dysentery. The spirochetes were obtained from scrapings of the colonic mucosa on the first day of diarrhea which was the time when the spirochete population was observed to be the highest. Of 29 exposed nonmedicated swine which developed and recovered from a diarrhea characteristic of swine dysentery 27 had antispirochete serum titers which ranged from 1:2 to 1:16. None of the 50 nonexposes swine developed a titer. Of 19 swine with a serum titer and reexposed with infective swine dysentery inoculum, 18 did not develop a diarrhea and were presumed to be immune. Considering these findings it is possible that this test could be used to detect antispirochete antibody in unknown swine serum.

Animals↗
PubMed2002

Novel swine virulence determinant in the left variable region of the African swine fever virus genome.

Previously we have shown that the African swine fever virus (ASFV) NL gene deletion mutant E70DeltaNL is attenuated in pigs. Our recent observations that NL gene deletion mutants of two additional pathogenic ASFV isolates, Malawi Lil-20/1 and Pr4, remained highly virulent in swine (100% mortality) suggested that these isolates encoded an additional virulence determinant(s) that was absent from E70. To map this putative virulence determinant, in vivo marker rescue experiments were performed by inoculating swine with infection-transfection lysates containing E70 NL deletion mutant virus (E70DeltaNL) and cosmid DNA clones from the Malawi NL gene deletion mutant (MalDeltaNL). A cosmid clone representing the left-hand 38-kb region (map units 0.05 to 0.26) of the MalDeltaNL genome was capable of restoring full virulence to E70DeltaNL. Southern blot analysis of recovered virulent viruses confirmed that they were recombinant E70DeltaNL genomes containing a 23- to 28-kb DNA fragment of the Malawi genome. These recombinants exhibited an unaltered MalDeltaNL disease and virulence phenotype when inoculated into swine. Additional in vivo marker rescue experiments identified a 20-kb fragment, encoding members of multigene families (MGF) 360 and 530, as being capable of fully restoring virulence to E70DeltaNL. Comparative nucleotide sequence analysis of the left variable region of the E70DeltaNL and Malawi Lil-20/1 genomes identified an 8-kb deletion in the E70DeltaNL isolate which resulted in the deletion and/or truncation of three MGF 360 genes and four MGF 530 genes. A recombinant MalDeltaNL deletion mutant lacking three members of each MGF gene family was constructed and evaluated for virulence in swine. The mutant virus replicated normally in macrophage cell culture but was avirulent in swine. Together, these results indicate that a region within the left variable region of the ASFV genome containing the MGF 360 and 530 genes represents a previously unrecognized virulence determinant for domestic swine.

African Swine Fever↗
PubMed1976

Haemagglutination-inhibiting antibodies against swine influenza and Hong Kong influenza viruses in swine sera in the USA.

Previous reports have established that swine in the midwestern states of the USA have a high incidence of classical swine influenza and that swine become infected with Hong Kong-like influenza viruses when these are prevalent in the human population. This investigation was undertaken to estimate, on the basis of 2245 sera collected randomly from swine going to slaughter in the USA during the summer months of 1974, how many of the animals had haemagglutination-inhibiting (HI) antibodies against swine influenza and Hong Kong influenza viruses. Based on HI titres of 20 or greater, our serological survey revealed that swine influenza virus infection was widespread throughout the USA, since 20.45% of the sera tested had positive HI titres. However, serological evidence of infection of swine with Hong Kong-like viruses was present in only 2.63% of the sera tested.

Animals↗
PubMed1977

Comparison of a new aminoglycoside (G-418) and gentamicin for the treatment of swine dysentery in swine naturally infected with Salmonella choleraesuis.

The addition of the aminoglycosidic antibiotic, G-418, to drinking water at the concentration of 37.5 mg/L for 3 days was effective in treatment of experimentally induced swine dysentery in swine. With this concentration, there was a recession of diarrhea during or immediately after withdrawal of medication. However, the diarrhea recurred approximately 2 weeks after medication was stopped. With the concentration of 12.5 mg of G-418/L given to swine for 3 days, the diarrhea did not recede during or after medication. With the concentration of 12.5 mg of gentamicin/L given to swine for 3 days, the diarrhea receded in some swine during and after medication, but more swine died in the medicated exposed groups than died in the nonmedicated exposed groups. Both drugs appeared to be effective against the concurrent spontaneous infection of Salmonella choleraesuis in the swine used in the study.

Administration, Oral↗
PubMedDate not supplied

Effects of anti-swine zona serum on swine and murine in vitro fertilization.

No investigations have been reported concerning the action of anti-swine zona (anti-SZ) antibodies in a swine in vitro fertilization (IVF) system. We examined the effects of anti-SZ on homologous swine IVF and heterologous murine IVF. Swine IVF and sperm-zona binding were inhibited after treating swine ova with 2(2) and 2(1) dilutions of antiserum, producing fertility rates of 25.9% and 1.6% respectively, which are significantly lower than the control group fertility rate of about 70%. However, the murine ova could accept the capacitated homologous sperm, even after treatment with the antiserum-derived IgG, which had an antibody titer twice that of the starting antiserum. The antiserum-reacted swine ova exhibited a zona precipitate and a concentration-dependent resistance to pronase and required about 17 minutes to disappear after reacting with the starting antiserum, whereas the antiserum-reacted murine ova, which did not exhibit a zona precipitate, and the control ova disappeared within three minutes. These results indicate that antibody deposition on the zona greatly affects the degree of fertilization inhibition. The immunogens used were characterized zona constituent glycoproteins, and the antiserum raised against them was previously proven to be highly specific. Therefore, we believe that a basis has been established for analyzing the fertilization phenomena that take place at the zona using swine systems.

Animals↗
PubMed2006

N-linked glycosylation status of classical swine fever virus strain Brescia E2 glycoprotein influences virulence in swine.

E2 is one of the three envelope glycoproteins of classical swine fever virus (CSFV). Previous studies indicate that E2 is involved in several functions, including virus attachment and entry to target cells, production of antibodies, induction of protective immune response in swine, and virulence. Here, we have investigated the role of E2 glycosylation of the highly virulent CSFV strain Brescia in infection of the natural host. Seven putative glycosylation sites in E2 were modified by site-directed mutagenesis of a CSFV Brescia infectious clone (BICv). A panel of virus mutants was obtained and used to investigate whether the removal of putative glycosylation sites in the E2 glycoprotein would affect viral virulence/pathogenesis in swine. We observed that rescue of viable virus was completely impaired by removal of all putative glycosylation sites in E2 but restored when mutation N185A reverted to wild-type asparagine produced viable virus that was attenuated in swine. Single mutations of each of the E2 glycosylation sites showed that amino acid N116 (N1v virus) was responsible for BICv attenuation. N1v efficiently protected swine from challenge with virulent BICv at 3 and 28 days postinfection, suggesting that glycosylation of E2 could be modified for development of classical swine fever live attenuated vaccines.

Animals↗
PubMed1994

Epidemiology of classical swine fever in Sardinia: a serological survey of wild boar and comparison with African swine fever.

A serological survey was carried out to establish the distribution of classical swine fever among wild boar in Sardinia, where that disease and African swine fever have been endemic in free-ranging domestic pigs and wild boar living in the mountainous areas of the province of Nuoro for several years. Blood samples were collected from 4752 wild boar shot during the period December 1988 to January 1992. An overall prevalence of 11 per cent was observed and the almost constant rate of about 9.8 per cent detected in the past three years indicates that the infection is well established. Wild boar seropositive to classical swine fever were found not only in the areas of the province of Nuoro where they share their habitat with free-ranging domestic pigs but also in other areas of the island where contacts between wild and domestic pigs are unlikely to occur. Therefore, transmission from wild boar to wild boar seems to play an important role in the spread and persistence of classical swine fever virus. In contrast, African swine fever virus is probably unable to persist in the wild boar population in the absence of the risk factor represented by their cohabitation with domestic free-ranging pigs infected with African swine fever.

African Swine Fever↗
PubMed1989

Virus-specific cellular blastogenesis and interleukin-2 production in swine after recovery from African swine fever.

Animals recovered from viral diseases represent an important model to study the host cellular and humoral immune responses to the etiologic agents. This is particularly important for African swine fever virus (ASFV) infections in which antibodies have little or no virus-neutralizing effect. Pigs surviving experimental infection with the naturally occurring low-virulent, nonhemadsorbing ASFV/NH/P68 (NHV) isolate did, however, exhibit virus-specific T-cell activities, as measured by a variety of assays. A strong virus-induced, antigen-specific blastogenic response was observed only with blood mononuclear cells (BMC) from ASF-recovered swine, whereas cells from recovered and naive swine responded similarly to the mitogens concanavalin A and phytohemagglutinin. The ASFV-induced blastogenesis was dependent on virus dose and on the presence of adherent cells. Blood mononuclear cells cultured with antigenically related hemadsorbing ASFV isolates of different virulence characteristics, the highly virulent L60 isolate and moderately virulent DRII isolate, exhibited a similar magnitude of blastogenesis to cells infected with the low-virulent NHV isolate. Virus-infected cells proved to be an efficient inducer of interleukin-2 (IL-2) activity to cells from recovered swine, but not from naive swine, whereas T-cell-specific lectins induced production of similar amounts of IL-2 activity from cells of naive and recovered swine. Correlated with the appearance of virus-induced IL-2 activity in the culture supernatant was the induction of promiscuous killing in cells exposed to prolonged (7 days) virus stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

African Swine Fever↗
PubMed1994

Origin and evolutionary pathways of the H1 hemagglutinin gene of avian, swine and human influenza viruses: cocirculation of two distinct lineages of swine virus.

The nucleotide sequences of the HA1 domain of the H1 hemagglutinin genes of A/duck/Hong Kong/36/76, A/duck/Hong Kong/196/77, A/sw/North Ireland/38, A/sw/Cambridge/39 and A/Yamagata/120/86 viruses were determined, and their evolutionary relationships were compared with those of previously sequenced hemagglutinin (H1) genes from avian, swine and human influenza viruses. A pairwise comparison of the nucleotide sequences revealed that the genes can be segregated into three groups, the avian, swine and human virus groups. With the exception of two swine strains isolated in the 1930s, a high degree of nucleotide sequence homology exists within the group. Two phylogenetic trees constructed from the substitutions at the synonymous site and the third codon position showed that the H1 hemagglutinin genes can be divided into three host-specific lineages. Examination of 21 hemagglutinin genes from the human and swine viruses revealed that two distinct lineages are present in the swine population. The swine strains, sw/North Ireland/38 and sw/Cambridge/39, are clearly on the human lineage, suggesting that they originate from a human A/WSN/33-like variant. However, the classic swine strain, sw/Iowa/15/30, and the contemporary human viruses are not direct descendants of the 1918 human pandemic strain, but did diverge from a common ancestral virus around 1905. Furthermore, previous to this the above mammalian viruses diverged from the lineage containing the avian viruses at about 1880.

Amino Acid Sequence↗