Liver-related biochemical changes in the serum of dogs being treated with phenobarbitone.

The concentrations of phenobarbitone, albumin, bile acids and cholesterol, and the activities of alkaline phosphatase (AP), alanine aminotransferase (ALT), gamma glutamyl transferase (GGT) and glutamate dehydrogenase (GLDH) were measured in the serum of 95 epileptic dogs whose clinical signs were controlled with phenobarbitone. The dogs were divided into groups on the basis of the concentration of phenobarbitone in their serum, the dose administered and the duration of the treatment. The concentration of phenobarbitone in serum was directly related to the activities of ALT, AP, GGT and GLDH and inversely related to the concentration of albumin. There was no significant relationship between the duration of treatment and the serum concentration of phenobarbitone, but there was a significant relationship between the duration of treatment and the activities of ALT, AP and GLDH. Thirty-five of the dogs (37 per cent) had serum activities of AP above the normal range, 19 had abnormally high activities of ALT, and 15 had high activities of GLDH, but these incidences were not related to the serum concentration of phenobarbitone. The dogs receiving higher doses for longer periods had the highest incidence of high activities of AP, ALT and GLDH. The concentration of bile acids in seven of the dogs was above the normal range but there was no relationship between the concentration and either the serum concentration, dose or duration of treatment with phenobarbitone.

Passive protection of calves against experimental infection with Salmonella typhimurium.

Cows were vaccinated with formalin-killed Salmonella typhimurium approximately seven weeks and two weeks before parturition to investigate whether passive immunity could protect their calves against experimental S typhimurium infection. After birth the calves were left with their dam for 48 hours and then separated and fed cold, stored colostrum from their own dam for a further eight days. Oral challenge five days after birth with 10(8) S typhimurium did not result in the death of these calves even when they had absorbed little colostrum. Mortality was reduced to 22 per cent in calves which sucked from vaccinated dams and were then fed colostrum from unvaccinated cows and to 50 per cent in calves born to unvaccinated cows and later fed colostrum from vaccinated animals. Calves which sucked from a vaccinated dam and then received stored colostrum from the same cow excreted salmonellas for significantly shorter periods after challenge and were less often infected at necropsy 28 days after inoculation. Protection was not correlated with the levels of O or H agglutinating antibodies in serum, which were at a maximum 24 hours after sucking and then slowly declined. There was no evidence of an active antibody response in the serum. Measurement of the O and H response of cows after vaccination indicated that the vaccination schedule could be improved. The highest levels of agglutinating antibody were measured between two and three weeks after the first vaccination and there was only a minimal response to the second vaccination before parturition.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental concurrent infection of cattle with Ostertagia ostertagi and Salmonella dublin.

Six seven-month-old Friesian steers were given 8.1 X 10(9) Salmonella dublin orally. Four had been infected with third stage larvae of Ostertagia ostertagi on four occasions over the previous three months. All became pyrexic and excreted S dublin in the faeces for eight to 15 days. Intravenous injection of 8.7 X 10(8) S dublin six weeks later produced similarly mild effects in parasitised and control animals alike. Two parasitised animals stopped excreting S dublin after three and five weeks respectively; the other four were still excreting regularly when killed eight weeks after intravenous infection. S dublin was recovered from the carcases of all six. O ostertagi, unlike Fasciola hepatica, did not increase susceptibility to S dublin or predispose to prolonged infection.

Salmonella saint-paul infection in two dairy herds.

An outbreak of salmonellosis due to Salmonella saint-paul in two dairy herds was first detected during routine examination of calves soon after calving; infection reached 100% amongst calves and up to 60% amongst milking cows. Excretion by cows continued for over 12 months and by calves for up to 18 months. The most important factor in controlling the spread of infection was reduction of environmental contamination by removal of carriers, prompt antibiotic treatment of sick calves and reduction in stocking densities.

Salmonella saint-paul infection in calves.

A natural outbreak of Salmonella saint-paul infection in two Institute herds was monitored clinically, bacteriologically and immunologically. This paper describes the findings in calves. Morbidity and mortality became apparent 30 days after S. saint-paul was first isolated on routine sampling of neonatal calf faeces. All heifer calves were treated with a tetracycline or ampicillin preparation when they showed clinical signs of disease, while the effects of intradermal vaccination with heat-killed S. saint-paul were assessed in a proportion of the bull calves. Antibiotic treatment reduced mortality and the number of persistent excretors; vaccination did not affect mortality but, if given during the first week of life, reduced the duration of faecal excretion. Calves which were untreated and unvaccinated, or vaccinated when older than 16 days, excreted S. saint-paul for periods of up to 18 months. Of six 'recovered' calves, which had been negative on faecal culture for 5-8 weeks, four yielded S. saint-paul at necropsy. Agglutinating antibody titres were highest in those unvaccinated calves which were persistent excretors.

Protection of cattle against experimentally induced salmonellosis by intradermal injection of heat-killed Salmonella dublin.

A single intradermal dose (7.5 mg) of heat-killed Salmonella dublin protected two out of three cattle against intravenous challenge with live S dublin. A second dose of 8 mg increased the protection rate to six out of seven. Four of the survivors had transient diarrhoea and S dublin was recovered from the carcases of four killed at four to 21 weeks after infection. Protected animals had elevated serum antibody titres and their serum passively protected rats against intraperitoneal challenge. The resistance of vaccinated cattle, presumably immunological in character, was not associated with leucocyte migration inhibition by salmonella antigen, depression of serum iron levels or haematological changes.

Responses of fluke-infected and fluke-free cattle to experimental reinfection with Salmonella dublin.

Cattle, aged nine to 18 months, were given sublethal doses of Salmonella dublin either intravenously, orally on two occasions, or by contact for 19 to 22 weeks with a persistent excretor. When challenged by intravenous injection of 10(9) S dublin at 10 to 22 weeks after their first exposure to S dublin 22 out of 36 animals survived. All similarly challenged cattle, which had not been previously exposed to S dublin, died. Infection with Fasciola hepatica did not alter the ability of cattle to survive reinfection with S dublin but the bacteria persisted in the tissues and were excreted in the faeces of fluke-infected animals for longer than in fluke-free animals. The ability to survive reinfection and to eliminate S dublin from the tissues was apparently unrelated to agglutinating antibody titres or delayed hypersensitivity.

Effects of Fasciola hepatica infection on responses of rats to reinfection with Salmonella dublin.

The survival rate of rats given potentially lethal doses of 7.6 X 10(8) to 10(9) Salmonella dublin intraperitoneally was enhanced in those which had been infected six weeks previously with 10(2) S dublin by the same route. Fasciola hepatica given six weeks before or one week after 10(2) S dublin did not alter the survival rate of rats reinfected with S dublin. However high levels (10(4) to 10(6) per g) of S dublin persisted in the tissues and faeces of fluke-infected but not of fluke-free rats. Agglutinating antibody responses to S dublin were unimpaired in fluke-infected rats but cutaneous delayed hypersensitivity reactions were slightly reduced. the humoral agglutinating antibody response may be important for survival of the host but other responses may be necessary for elimination of S dublin from the tissues.

Immunological responses of fluke-infected and fluke-free cattle to Salmonella dublin and other antigens.

Immune responses to heat-killed Brucella abortus strain 19 and to ovalbumin were compared in 15 fluke-infected and 15 fluke-free Friesian heifers. B abortus was injected 16 weeks and ovalbumin 19 weeks after the oral administration of 1000 metacercariae of Fasciola hepatica. Agglutinating antibody responses to B abortus were similar in both groups. Immediate type hypersensitivity to ovalbumin was apparently suppressed in fluke-infected animals when assessed by active and passive cutaneous anaphylaxis two weeks after sensitisation. However, when assessed by Schultz-Dale responses of intestine, in vitro, 36 weeks after sensitisation there was no difference between the groups. The heifers were subsequently given live Salmonella dublin intravenously. The fluke-infected animals which became carriers of S dublin had the most persistently elevated titres of agglutinating antibodies in their sera and the highest incidence of immediate-type hypersensitivity, as assessed by Schultz-Dale responses of intestine, but the weakest cutaneous delayed hypersensitivity reactions to S dublin. The latter might have been related to lymphopenia which developed after fluke infection. The increased susceptibility of fluke-infected cattle to S dublin cannot be attributed to impaired agglutinin responses but may result from effects on cell-mediated mechanisms.

The serology of experimental Salmonella dublin infections of cattle.

Agglutinating antibodies to somatic "O" and flagellar "H" antigens of S. dublin were measured in the serum of 43 pregnant heifers before intravenous or oral infection with S. dublin and in the serum of 21 uninfected control animals. The data from these animals were analysed statistically and a titre of 1/80, to both antigens, has been interpreted as of doubtful significance and a titre of 1/160 to both antigens, has been interpreted as significantly raised. Animals in which fetal infection occurred after challenge by either the intravenous or oral route developed significant increases in "H" and "O" titres indicating the value of measure "H" titres in the diagnosis of S. dublin abortion. In animals which were infected orally and in which infection appeared to be confined to the alimentary tract the "H" titre did not become significantly raised. Lack of correlation between antibody titres and faecal excretion of S. dublin and persistence of infection in carcasses confirms that the serum agglutination test is of no value in detecting latent carriers.