Salmonella gallinarum field isolates of the biovars pullorum and gallinarum

In 40 cases salmonellae of the serovar Salmonella (S.) gallinarum were culturally isolated from domesticated gallinaceous birds submitted for diagnostic purposes in the period of 1979-1989. On the basis of the cultural and biochemical features found 35 of them could be assigned to the biovar Pullorum and 5 to the biovar Gallinarum. Of 35 isolates of the biovar Pullorum, 29 were isolated from pure bred chickens of small fancy-exhibition type flocks, 4 from floor-housed adult brown hybrid laying hens and one each from broiler chicks and pheasant chicks (Phasianus colchicus). Acute to subacute courses of the pullorum disease were observed in the 4 flocks of brown hybrid hens. Of 5 isolates of the biovar Gallinarum, 4 were isolated from adult brown hybrid laying hens kept in battery cages and one from floor-housed brown hybrid pullets of the laying type. First cases of fowl typhoid occurred early in the summer of 1988. The disease was characterized by a peracute course in the 4 flocks of brown laying hens and by a more acute course in the pullet flock. The primary source of the fowl typhoid producing organisms was not elucidated.     

Some serological reactions to "brucella" antigen in the horse.

Seventy-three samples of serum, from 69 horses and one zebra, were subjected to the Rose Bengal Plate, serum tube agglutination, complement fixation, and anti-equine globulin (Coombs') tests for brucellosis. Fifty-one of the samples, from 48 horses, were submitted by practising veterinary surgeons; of these, 22 samples were associated with clinical conditions which might have been due to brucellosis. Fourteen samples were from healthy horses known to have been in contact with infected cattle, and six were from horses which were known not to have been exposed to brucellosis. More reactions at accepted diagnostic levels were obtained to the anti-globulin and complement fixation tests than to the agglutination test. Two horses showed no reactions, other than inconclusive titres to the antiglobulin test, and these titres could have resulted from exposure to Brucella. Eight of nine positive Rose Bengal tests were confirmed by a reaction at diagnostic level in at least one of the other tests, but two sera showing a reaction at diagnostic level to the other tests gave a negative Rose Bengal result.     

Reduction of non-specific reactions to the Brucella abortus serum agglutination test by the addition of EDTA

Serum samples taken from cattle known to be infected with Brucella abortus, and samples routinely collected as part of the brucellosis eradication scheme were tested by the serum agglutination test (SAT), complement fixation test (CFT) and the SAT modified by the addition of ethylene diamine tetra-acetic acid (EDTA). In 64 per cent of the samples giving an SAT titre greater than 100 iu, but a CFT titre 8.3 icftu or less, the agglutination reaction was sufficiently affected by the action of EDTA for the titre to drop to below 100 iu. Only 5 per cent of samples giving an SAT titre greater than 100 iu and a CFT titre of 20 icftu or greater were affected in a similar manner by EDTA, and none of the 29 sera taken from known infected animals showed a drop in titre to below 100 iu, although some with titres greater than 500 iu did show significant EDTA sensitivity.     

Haematological, serological and pathological effects in chicks of one or more intravenous injections of Salmonella gallinarum endotoxin

Abnormalities appeared a few hours after groups of 14-day-old chicks (Gallus domesticus) were injected intravenously with 15 mg/kg of endotoxin (LPS) from Salmonella gallinarum. Clinical illness without mortality was accompanied by significant (P less than 0.05) falls in body temperature, bursa weight, the main haematological parameters, serum iron (SI) and transferrin saturation (TS) and a significant increase in unsaturated iron-binding capacity. All responses, apart from bursa weight, SI values and total and differential white-cell counts, returned to normal within 24 to 48 h. LPS given daily for three consecutive days did not cause changes in the main haematological parameters during the 48 h period following the third injection. However body and bursa weight and heterophil counts were significantly depressed, whereas body temperature, SI and TS were affected biphasically, being first depressed and then raised above normal. Chicks injected with LPS daily for six consecutive days showed broadly similar responses but a persistent microcytosis was also present.     

The spread of Salmonella gallinarum 9R vaccine strain under field conditions.

A live vaccine based on an attenuated Salmonella gallinarum 9R strain is in use in a Salmonella enteritidis control program in commercial layer flocks in The Netherlands. In a field study, the potential spread of the vaccine strain from vaccinated flocks to nonvaccinated flocks has been studied after both the primary and the booster injection at four different rearing farms and at one layer farm. The vaccinated and the nonvaccinated flocks were monitored at regular intervals by bacteriologic and serologic examination. In this field study, no evidence was found for the fecal spread of the vaccine strain.     

The selection of Salmonella gallinarum, Salmonella pullorum and Escherichia coli in chickens after chloramphenicol administration]

The effect of a chloramphenicol administration was examined on the selection of E. coli of the chicken intestinal flora, and of the infectious S. gallinarum and S. pullorum strains. On the other hand, an effort was made to detect the frequency of the resistance transmission of E. coli to above mentioned sensitive salmonella strains. Fourteen chicken, 12 infected and 2 negative controls were used. It was found that the enteric E. coli strains became resistant in a week's time. Besides, the strains that were used for infecting the chicken neither were selected through the chloramphenicol administered nor did they take the E. coli resistance, via R-factor transmission.     

Experimental induction of an immunohaemolytic anaemia in the chicken with Salmonella gallinarum endotoxin.

The possibility that the extreme refractoriness of the chicken to injected endotoxin would permit the buildup of sufficient free endotoxin in the circulation to immunologically modify the erythrocytes in vivo and thereby cause them to be eliminated from the circulation was investigated. It was shown that a moderately severe immunohaemolytic anaemia accompanied by a mild spenomegaly could be induced in chickens by single (large) or multiple injections of Salmonella gallinarum endotoxin (SgE). Varying degrees of reticulocytosis, with corresponding decreases in haemoglobin and haematocrit values, were observed from the tenth day after the injection of the SgE. All the injected animals also showed significant immune responses to SgE, peak haemagglutinin titres occurring coincidentally with the peaks of the haemolytic episodes. A similar injection schedule in specifically immune chickens also showed the anaemia appearing much earlier, persisting longer and being much more profound in intensity. It is considered that the in vivo erythrocyte sensitization induced by SgE injection initiates the erythrocytic changes observed and that the underlying mechanism responsible for the subsequent development of the haemolytic anaemia is immunologically mediated.