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Role of carriers in the transmission of pneumonia in bighorn sheep (Ovis canadensis).

Raghavan B, Erickson K, Kugadas A, Batra SA, Call DR, Davis MA, Foreyt WJ, Srikumaran S - Biol Open (2016)

Bottom Line: To investigate this problem we commingled naïve, pregnant ewes (n=3) with previously exposed rams (n=2).Antibody titers against leukotoxin-producing Pasteurellaceae in all eight ewes were 'protective' (>1:800 and no apparent respiratory disease); however their lambs were either born with comparatively low titers, or with high (but non-protective) titers that declined rapidly within 2-8 weeks of age, rendering them susceptible to fatal disease.Thus, exposure to pneumonia-causing pathogens from carrier ewes, and inadequate titers of maternally derived protective antibodies, are likely to render bighorn lambs susceptible to fatal pneumonia.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, WA 99163, USA.

No MeSH data available.


Related in: MedlinePlus

Titers of leukotoxin-neutralizing antibodies (lkt-nAb) in bighorn carrier rams, commingled naïve pregnant ewes and lambs born to the ewes (Study 1). Bighorn rams (n=2; T113 and T114) from a pneumonia-affected herd in Nevada were commingled with naïve, healthy, pregnant ewes (n=3; 142, 11, 6) from the WSU breeding herd. Lambs (n=3; 142A, 11A, 6A) were born one month post-commingling. Serum samples were collected at bi-weekly intervals. Lkt-nAb titers were measured using an MTT dye-reduction cytotoxicity inhibition assay and transformed to natural log (ln) for analysis. Each sample was tested in three independent experiments. Titers differed significantly between carrier rams and naïve ewes (P=0.00) based on two-sample, two-tailed t-test with alpha=0.05. Based on previous studies, protective titers were defined as titers >6.68 (>1:800). Pre-C, pre- commingling; Post-C, post-commingling.
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BIO018234F1: Titers of leukotoxin-neutralizing antibodies (lkt-nAb) in bighorn carrier rams, commingled naïve pregnant ewes and lambs born to the ewes (Study 1). Bighorn rams (n=2; T113 and T114) from a pneumonia-affected herd in Nevada were commingled with naïve, healthy, pregnant ewes (n=3; 142, 11, 6) from the WSU breeding herd. Lambs (n=3; 142A, 11A, 6A) were born one month post-commingling. Serum samples were collected at bi-weekly intervals. Lkt-nAb titers were measured using an MTT dye-reduction cytotoxicity inhibition assay and transformed to natural log (ln) for analysis. Each sample was tested in three independent experiments. Titers differed significantly between carrier rams and naïve ewes (P=0.00) based on two-sample, two-tailed t-test with alpha=0.05. Based on previous studies, protective titers were defined as titers >6.68 (>1:800). Pre-C, pre- commingling; Post-C, post-commingling.

Mentions: Prior to commingling with carrier rams, the three ewes in the treatment group (6, 11 and 142) tested PCR-negative for lkt+ Pasteurellaceae and M. ovipneumoniae (Table 1). They had negligible titers of lkt-nAb (Fig. 1) and were seronegative for M. ovipneumoniae (Table 1). They also had low titers of antibodies against M. haemolytica surface antigens (6.9; Fig. 2). None of the ewes had any clinical signs of pneumonia or other respiratory disorders.Table 1.


Role of carriers in the transmission of pneumonia in bighorn sheep (Ovis canadensis).

Raghavan B, Erickson K, Kugadas A, Batra SA, Call DR, Davis MA, Foreyt WJ, Srikumaran S - Biol Open (2016)

Titers of leukotoxin-neutralizing antibodies (lkt-nAb) in bighorn carrier rams, commingled naïve pregnant ewes and lambs born to the ewes (Study 1). Bighorn rams (n=2; T113 and T114) from a pneumonia-affected herd in Nevada were commingled with naïve, healthy, pregnant ewes (n=3; 142, 11, 6) from the WSU breeding herd. Lambs (n=3; 142A, 11A, 6A) were born one month post-commingling. Serum samples were collected at bi-weekly intervals. Lkt-nAb titers were measured using an MTT dye-reduction cytotoxicity inhibition assay and transformed to natural log (ln) for analysis. Each sample was tested in three independent experiments. Titers differed significantly between carrier rams and naïve ewes (P=0.00) based on two-sample, two-tailed t-test with alpha=0.05. Based on previous studies, protective titers were defined as titers >6.68 (>1:800). Pre-C, pre- commingling; Post-C, post-commingling.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4920194&req=5

BIO018234F1: Titers of leukotoxin-neutralizing antibodies (lkt-nAb) in bighorn carrier rams, commingled naïve pregnant ewes and lambs born to the ewes (Study 1). Bighorn rams (n=2; T113 and T114) from a pneumonia-affected herd in Nevada were commingled with naïve, healthy, pregnant ewes (n=3; 142, 11, 6) from the WSU breeding herd. Lambs (n=3; 142A, 11A, 6A) were born one month post-commingling. Serum samples were collected at bi-weekly intervals. Lkt-nAb titers were measured using an MTT dye-reduction cytotoxicity inhibition assay and transformed to natural log (ln) for analysis. Each sample was tested in three independent experiments. Titers differed significantly between carrier rams and naïve ewes (P=0.00) based on two-sample, two-tailed t-test with alpha=0.05. Based on previous studies, protective titers were defined as titers >6.68 (>1:800). Pre-C, pre- commingling; Post-C, post-commingling.
Mentions: Prior to commingling with carrier rams, the three ewes in the treatment group (6, 11 and 142) tested PCR-negative for lkt+ Pasteurellaceae and M. ovipneumoniae (Table 1). They had negligible titers of lkt-nAb (Fig. 1) and were seronegative for M. ovipneumoniae (Table 1). They also had low titers of antibodies against M. haemolytica surface antigens (6.9; Fig. 2). None of the ewes had any clinical signs of pneumonia or other respiratory disorders.Table 1.

Bottom Line: To investigate this problem we commingled naïve, pregnant ewes (n=3) with previously exposed rams (n=2).Antibody titers against leukotoxin-producing Pasteurellaceae in all eight ewes were 'protective' (>1:800 and no apparent respiratory disease); however their lambs were either born with comparatively low titers, or with high (but non-protective) titers that declined rapidly within 2-8 weeks of age, rendering them susceptible to fatal disease.Thus, exposure to pneumonia-causing pathogens from carrier ewes, and inadequate titers of maternally derived protective antibodies, are likely to render bighorn lambs susceptible to fatal pneumonia.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, WA 99163, USA.

No MeSH data available.


Related in: MedlinePlus