A diagnostic approach to confirm Mycoplasma hyopneumoniae “Day zero” for pathogen eradication

Elsevier 2023-12

Breeding herds in the US are trending toward eradication of Mycoplasma hyopneumoniae (M. hyopneumoniae) due to the positive impact on welfare and downstream production. In an eradication program, "Day 0″ is the time point when the last replacement gilts to enter the herd were exposed to M. hyopneumoniae and marks the beginning of a herd closure. However, no specific diagnostic protocols are available for confirmation of successful exposure to define Day 0. Therefore, the objective of this study was to develop diagnostic guidelines, including sample collection approaches, for two common gilt exposure methods to confirm an entire population has been infected with M. hyopneumoniae following purposeful exposure. Forty gilts, age 21-56 days, were ear-tagged for longitudinal sample collection at five commercial gilt developer units (GDUs) and were exposed to M. hyopneumoniae by natural contact or aerosolization. Study gilts originated from sources known to be negative to major swine pathogens, including M. hyopneumoniae, and were sampled prior to exposure to confirm negative status, then every two weeks. Blood samples were collected for antibody detection, while laryngeal and deep tracheal secretions and pen based oral fluids were collected for PCR, and sampling continued until at least 85% of samples were positive by PCR. Detection of M. hyopneumoniae varied greatly based on sample type. Oral fluids showed the lowest detection in groups of gilts detected positive by other sample types. Detection by PCR in deep tracheal secretions was higher than in laryngeal secretions. Seroconversion to and PCR detection of M. hyopneumoniae on oral fluids were delayed compared to PCR detection at the individual level. By two weeks post-exposure, at least 85% of study gilts in three GDUs exposed by aerosolization were PCR positive in deep tracheal secretions. Natural contact exposure resulted in 22.5% of study gilts becoming PCR positive by two weeks post-initial exposure, 61.5% at four
Boehringer Ingelheim Animal Health USA Inc
Depto. de Sanidad Animal
Centro de Vigilancia Sanitaria Veterinaria (VISAVET)
TRUE
pub

636.09; Mycoplasma hyopneumoniae; Gilt; Exposure; Diagnostic protocol; Day zero; Disease eradication; Veterinaria; 3109 Ciencias Veterinarias; journal article; VoR

Open access content. Open access content
Attribution 4.0 International
http://creativecommons.org/licenses/by/4.0
open access

application/pdf
0167-5877
English

ESRCM oai:docta.ucm.es:20.500.14352/107431
0167-5877
10.1016/j.prevetmed.2023.106057
1457228120

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