Suspected aerosol transmission of swine pathogens: A field case.

A swine production system had 3 sections located a few kilometers apart. Sections A and C contained several thousand sows and nursery and finishing pigs. Section B, located between the other 2 sections, was the smallest and had 6 finishing sites and 2 sow sites. The entire system was infected with porcine reproductive and respiratory syndrome virus, Mycoplasma hyopneumoniae, and Actinobacillus pleuropneumoniae. Section B was depopulated, cleaned, disinfected, and repopulated with negative gilts. Despite extreme measures, recontamination occurred for each pathogen, with aerosol considered the most plausible contamination source.

Transmission suspectée d'agents pathogènes porcins par aérosol : un cas de terrainUn système de production porcine comportait 3 sections situées à quelques kilomètres l'une de l'autre. Les sections A et C contenaient plusieurs milliers de truies et de porcs en maternité et en finition. La section B, située entre les 2 autres sections, était la plus petite et comptait 6 sites de finition et 2 sites de truies. L'ensemble du système était infecté par le virus du syndrome reproducteur et respiratoire porcin, Mycoplasma hyopneumoniae et Actinobacillus pleuropneumoniae. La section B a été dépeuplée, nettoyée, désinfectée et repeuplée de cochettes négatives. Malgré des mesures extrêmes, une recontamination s'est produite pour chaque agent pathogène, les aérosols étant considérés comme la source de contamination la plus plausible.(Traduit par Dr Serge Messier).

Aerosol transmission of porcine reproductive and respiratory syndrome virus: How frequently and what distance?

Some early reports concluded aerosol transmission of porcine reproductive and respiratory syndrome virus between swine farms was unlikely, but most current information suggests the opposite; in many situations it may be the most important contamination source. Aerosol transmission can apparently occur over several km, but more information is required to confirm and better quantify possible distances.

Transmission par aérosol du virus du syndrome reproducteur et respiratoire porcin : à quelle fréquence et sur quelle distance? Quelques rapports antérieurs ont conclu que la transmission par aérosol du virus du syndrome reproducteur et respiratoire porcin entre des fermes porcines était peu probable, mais les informations les plus à jour suggèrent le contraire; dans plusieurs situations cela pourrait être la source la plus importante de contamination. La transmission par aérosol pourrait survenir sur plusieurs kilomètres, mais des informations supplémentaires sont requises pour confirmer et mieux quantifier les distances possibles.(Traduit par Dr Serge Messier).

An investigation of porcine reproductive and respiratory syndrome outbreaks.

Within 16 d, a small farrow-to-finish operation and 2 sow herds broke with the same strain of porcine reproductive and respiratory syndrome (PRRS) virus. Although no certainty could be obtained, based on the epidemiological investigation that was undertaken, we inferred that the most plausible source of contamination was aerosol, over a distance of at least 6.1 km.

Une enquête sur des éclosions de syndrome reproducteur et respiratoire porcin. En 16 jours, une petite exploitation de naissage-engraissement et deux troupeaux de truies ont été infectés avec la même souche du virus du syndrome reproducteur et respiratoire porcin (PRRS). Bien qu'aucune certitude n'ait pu être obtenue, sur la base de l'enquête épidémiologique qui a été entreprise, nous avons déduit que la source de contamination la plus plausible était des aérosols, sur une distance d'au moins 6,1 km.(Traduit par Dr Serge Messier).

Transmission of swine pathogens: different means, different needs.

There seems to be two main types of pathogens that cause diseases in swine: those that are mainly introduced through direct pig contacts, and those that are often, and in some situations mainly introduced by indirect transmission means. In this review, the mange mite (Sarcoptes scabiei), toxigenic Pasteurella multocida and Brachyspira hyodysenteriae will be used as examples of the first type, and foot and mouth disease virus, Mycoplasma hyopneumoniae and porcine reproductive and respiratory syndrome (PRRS) virus as examples of the second. It is now clear from various epidemiological studies as well as experimental and field data that aerosol transmission of some swine pathogens plays an important role in their epidemiology. As previous biosecurity programs did not take this factor into consideration, it can at least partially explain why many of these programs suffered frequent failures and why air filtration is now becoming increasingly popular in North America. Identifying and quantifying transmission means should be a priority for every important infectious disease for which it has not been done.

Diagnostic and epidemiological features of Lawsonia intracellularis enteropathy in 2 foals.

Two clinical cases of equine proliferative enteropathy are described. Both foals had a positive fecal polymerase chain reaction, but shedding of the bacterium stopped <4 days after therapy was initiated. One foal was serologically positive 3 days after onset of clinical signs and remained positive for more than 6 months.