Transmission of Mycoplasma hyopneumoniae in a farm with solid or open pen partitions determined by polymerase chain reaction test

Abstract

THE DYNAMICS OF TRANSMISSION OF MYCOPLASMA HYOPNEUMONIAE ARE DESCRIBED IN A CONVENTIONAL NURSERY FITTED WITH TWO DIFFERENT PEN PARTITION DESIGNS (OPEN VS. SOLID), AS VARIABLES THAT INFL UENCES THE SPREAD OF THIS ORGANISM. THIS STUDY WAS CONDUCTED IN A FARM KNOWN TO BE M. HYOPNEUMONIAE POSITIVE WITH A 50% PREVALENCE OF PCR POSITIVE PIGS AT WEANING. THIS FARM HAD TWO NURSERY ROOMS (6 PENS/ROOM): ONE ROOM WAS LEFT WITH THE ORIGINAL OPEN PEN PARTITIONS; PENS IN THE OTHER ROOM WERE MODIFIED BY INSTALLING SOLID PARTITIONS USING WASHABLE PLYWOOD. IN ADDITION, TWO GROUPS OF PIGS (16 PIGS/GROUP) WERE PURCHASED FROM A M. HYOPNEUMONIAE NEGATIVE FARM (TEST PIGS) AND PLACED IN ALTERNATE PENS IN THE NURSERY ROOMS (2 PENS/ROOM). THE REST OF THE PENS WERE FILLED WITH PIGS FROM THE HOME FARM (10 PIGS/PEN). TEST PIGS AND TWO HOMEGROWN PIGS FROM EACH PEN WERE SAMPLED THROUGHOUT THE NURSERY PERIOD BY NASAL SWABBING; BLOOD SAMPLES WERE ALSO TAKEN. THE NASAL SWABS WERE THEN ANALYZED BY NESTED-PCR AND THE BLOOD SAMPLES BY THE TWEEN-ELISA. RESULTS REVEALED NO STATISTIC DIFFERENCES IN M. HYOPNEUMONIAE TRANSMISSION BETWEEN GROUPS HOUSED EITHER IN THE OPEN OR SOLID PEN PARTITIONS ROOMS. RESULTS ALSO SHOWED THAT M. HYOPNEUMONIAE WAS TRANSMITTED SLOWLY WITHIN THE NURSERY ROOMS UP TO A POINT WHERE A SUDDEN INCREASE OF INFECTION OCCURRED.TRANSMISSION OF M. HYOPNEUMONIAE IN CONFINED NURSERY ROOMS IS NOT AFFECTED BY PEN PARTITION DESIGN. TRANSMISSION BETWEEN INFECTED AND CONTROL PIGS APPEARS TO BE AFFECTED BY FACTORS THAT INFL UENCE MICROBIAL SHEDDING. PCR PROVED TO BE A USEFUL TOOL TO DETECT THE TRANSMISSION OF M. HYOPNEUMONIAE IN THE LACTATION ROOMS OF THE FARMS.