Cross protection among Haemophilus parasuis strains in immunized gnotobiotic pigs.

In an attempt to establish if cross protection can be induced by different strains of Haemophilus parasuis, three groups of 12 gnotobiotic pigs were immunized each with an aluminum hydroxide adsorbed whole cell bacterin of one of three H. parasuis strains. Two weeks later, four pigs within each vaccinated group were challenged with aerosols of live cultures of each of the three test strains and observed for response.

Vaccination of gnotobiotic primary specific pathogen-free pigs against Haemophilus parasuis.

Three trials were conducted to establish if young primary specific pathogen free (SPF) pigs could be protected from Glasser's disease by vaccination. Three age groups of cesarean-derived isolator-reared gnotobiotic pigs were vaccinated twice at 4 and 6, 3 and 5, and 2 and 4 wk of age respectively with a formalin killed aluminum hydroxide adsorbed bacterin prepared from three strains of Haemophilus parasuis isolated from Ontario pigs affected with Glasser's disease. When challenged two weeks later with the homologous strains of virulent bacteria, all the vaccinated pigs remained healthy, while 17/18 nonvaccinated pigs became severely sick or died between three and seven days postchallenge.

Actinobacillus suis septicemia in mature swine: two outbreaks resembling erysipelas.

In the winter of 1987/88 a previously unrecognized septicemic disease syndrome - actinobacillosis in mature sows and gilts - was diagnosed in two minimal-disease swine herds in southwestern Ontario. In herd 1, 34 sows, 2 boars, 13 feeder pigs, and 30 suckling pigs were affected; 11 sows, 2 feeders, and 18 suckling pigs died. In herd 2, 13 sows and 1 feeder pig were affected; 1 sow and 1 feeder pig died.

Preliminary assessment of a Haemophilus parasuis bacterin for use in specific pathogen free swine.

A whole cell formalin killed trivalent Haemophilus parasuis bacterin was tested for efficacy in four week old, weaned specific pathogen free pigs challenged under laboratory conditions. The vaccine contained three field strains of H. parasuis selected from confirmed cases of Glasser's disease.

Glasser's disease and prevalence of subclinical infection with Haemophilus parasuis in swine in southern Ontario.

Glasser's disease accounted for less than 1% of total swine mortalities in an 11 year retrospective postmortem survey of swine submissions at three provincial government diagnostic laboratories in southern Ontario. However, Glasser's disease was suspected in 17 of 83 boar mortalities at the Record of Production Boar Test Station between 1983 and 1985 and was much more common in specific-pathogen-free (SPF) boars than in conventional boars. The prevalence of the causative organism, Haemophilus parasuis, was determined for 19 SPF herds in Ontario classified as "Excellent" under the Ontario Swine Herd Health Policy.

Analysis of Haemophilus parasuis isolates from southern Ontario swine by restriction endonuclease fingerprinting.

To study the occurrence and distribution of various strains of Haemophilus parasuis in southern Ontario swine, organisms isolated from healthy swine, from specific pathogen-free and conventional herds, and from disease cases were examined using restriction endonuclease fingerprinting analysis. In most herds, several strains of H. parasuis could be detected although one or two strains usually predominated.

Protective efficacy of capsule extracts of Haemophilus pleuropneumoniae in pigs and mice.

Capsular extracts of Haemophilus pleuropneumoniae, Serotype 1, were mixed with AL(OH)3 gel (3 parts extract + 1 part Al(OH)3) and used as vaccines in pigs and mice. Four preparations were tested in Experiment I: NaCl and Cetavlon (hexadecyltrimethyl ammonium bromide) extracts of both low in vitro passage (LP) and high in vitro passage (HP) culture, respectively. Four pigs vaccinated with the NaCl extract of the LP strain survived, whereas one of four from each of the remaining vaccine groups and five of six from the control group died.

Impact of chronic protein-calorie malnutrition on small intestinal repair after acute viral enteritis: a study in gnotobiotic piglets.

To investigate the effect of chronic protein-calorie malnutrition on intestinal repair after an enteric infection, we examined small intestinal structure, enzyme activity, and sodium transport in undernourished piglets during the acute and convalescent phases of a viral enteritis, transmissible gastroenteritis (TGE). Gnotobiotic pigs, nutritionally deprived from the age of 7 days, gained less weight than dietary controls from 14 days of age until the end of the study. Animals from malnourished and control diet groups were inoculated with TGE virus at 22-23 days and studied during the acute (40 h) and convalescent (4, 10, and 15 days) stages of this experimental enteritis along with noninfected dietary controls.

Campylobacter jejuni colitis in gnotobiotic dogs.

Campylobacter jejuni of human and canine origin was inoculated orally into six gnotobiotically reared Beagle puppies and reactions were compared with two controls. Inoculated dogs developed transient lassitude, inappetence, mild diarrhea and tenesmus during the period 36-72 hours after inoculation. Pairs of dogs killed 43 hours, and five and seven days after inoculation had lesions limited to typhlitis and colitis.

Experimental atrophic rhinitis in gnotobiotic pigs.

Twenty-nine caesarian derived colostrum deprived germfree pigs were reared in isolators in groups of three to four per isolator. At seven days of age each group was inoculated intranasally with one of four strains of Bordetella bronchiseptica (designated B, J, L and 55B), or Pseudomonas aeruginosa or a mucoid strain of Escherichia coli, all previously isolated from nasal mucus of pigs affected with clinical atrophic rhinitis. Another group was inoculated simultaneously with B.

Gnotobiotic pigs-derivation and rearing.

The procurement, rearing, nutrition and microbiological monitoring of gnotobiotic pigs and a method for conditioning of primary, colostrum-deprived, specific pathogen free pigs is described. As compared to the established hysterectomy and closed hysterotomy methods for the derivation of gnotobiotic piglets an alternative approach, open caesarian section with the sow maintained under general halothane-nitrous oxide anaesthesia and the introduction of each fetus into the sterile isolator via a liquid germicidal trap, was found to be more efficient and equally successful in providing viable and microbiologically sterile piglets. Two sterile commercially available milk diets, a special formula for orphan animals and condensed cow's milk, when the latter was supplemented with injectable vitamin E, selenium and iron, proved adequate for satisfactory health of the animals.

Experimental polychlorinated biphenyl toxicosis in germfree pigs.

The effects of polychlorinated biphenyls were studied in eight germfree pigs. Beginning at fourteen days of age, two pigs each were fed daily 12.5, 25, 50 and 100 mg/kg body weight of polychlorinated biphenyls as Aroclor 1254.

Swine dysentery: inoculation of gnotobiotic pigs with Treponema hyodysenteriae and Vibrio coli and a Peptostreptococcus.

Pure cultures of Treponema hyodysenteriae given orally to conventional pigs resulted in the development of swine dysentery, whereas identical cultures given to gnotobiotic pigs did not produce the disease. Oral inoculation of gnotobiotic pigs with Vibrio coli and/or a peptostreptococcus in addition to T. hyodysenteriae did not result in dysentery.

The significance of proliferation and enterotoxin production by Escherichia coli in the intestine of gnotobiotic pigs.

The significance of enterotoxin production and proliferative ability of Escherichia coli in the intestinal tract as related to porcine enteric colibacillosis was studied in 68 gnotobiotic pigs. The animals were monocontaminated at seven to ten days of age with eight selected strains of E. coli.

Response of gnotobiotic pigs to Escherichia coli.

In a study of the response of gnotobiotic pigs to coliform infections, 45 one-week-old germfree pigs were divided into five groups and each group was inoculated orally with a different strain of Escherichia coli. Three of these were enteropathogenic swine strains, P307[08:K87(B), K88 a,b (L):H19]; P570 [0138:K81]; P568[0141:K85a,b(B), K88a,b(L):H4], one was a virulent human strain, H224, [026:K60(B6)], and one was a non-enteropathogenic swine strain, P581[OX13:K68]. It was attempted to protect a portion of the pigs with orally administered specific antisera and sera from non-immunized specific pathogenfree (SPF) pigs.