Prevalence of antibodies to Toxoplasma gondii in cattle and swine in The Netherlands: towards an integrated control of livestock production.

Serological surveys of the prevalence of antibodies against Toxoplasma gondii were carried out amongst swine and cattle in the Netherlands. Data were analysed according to the different categories of animals. The results show very low seroprevalences of Toxoplasma gondii in finishing pigs (1.8%) and in fattening calves (1.2%). In sows and dairy cattle, respectively, seroprevalences of 30.9% and 27.9% respectively, were found, demonstrating clearly the environmental infection pressure and illustrating the importance of housing and management in establishing low infection rates. Substantially different seroprevalences were found between dairy cattle sampled in the North and in the South of the Netherlands (13.1% and 42.6%, respectively). The infection rates in the samples from finishing pigs, fattening calves, and dairy cattle demonstrate that seroprevalences in individual farms or herds may differ considerably. Investigation of the factors involved can be useful in determining the causes of infection and for developing measures with regard to prevention. The very low seroprevalences in finishing pigs and fattening calves indicate, however, that the production of toxoplasma-free meat may be well within reach in modern husbandry. Since farm animals easily are infected, serological screening of individual farms or herds for the absence of T. gondii infection, as a part of the Integrated Quality Control programme, can be helpful in determining the quality of livestock production and in developing certain standards of hygiene for individual farms.

[Study of hemolytic staphylococci in slaughtering animals]. / Onderzoek naar hemolytische stafylokokken bij slachtdieren.

Haemolysis as the sole criterion of the pathogenicity of staphylococci detected on bacteriological examination of slaughtered animals should be reconsidered.

[Reconsideration of the 'bacteriological examination' of slaughter stock]. / Herbezinning over het 'Bacteriologisch Onderzoek' van slachtdieren.

A comparative trial was made by six meat inspection services to attain uniform indications for the 'Bacteriological Examination' of slaughtered animals in accordance with the 'Meat Inspection Regulations' of the Dutch 'Meat Inspection Act'. The results of the study compelled the investigators to scrutinize these regulations. The 'Bacteriological Examination' which is prescribed, is designed to exclude septicaemic animals from human consumption. Applying the rules will result in condemnation of animals harbouring a small number of bacteria which have a minimum significance for the health of consumers, whereas animals harbouring organisms potentially pathogenic for man are overlooked. It is concluded that the 'Meat Inspection Regulations' should be considered.

Fate of salmonellas and competing flora in meat sample enrichments in buffered peptone water and in Muller-Kauffmann's tetrathionate medium.

Studies have been carried out in which growth patterns of a Salmonella sp. and competing micro-organisms, especially other Enterobacteriaceae, were followed during pre-enrichment in buffered peptone water (BPw) and subsequent selective enrichment in tetrathionate broth (TBB). Pre-enrichment cultures were inoculated with minced meat and three reference samples containing nalidixic acid-resistant salmonellas. Irrespective of their initial numbers in BPw, Enterobacteriaceae increased to 10(8)/ml or more. During incubation in TBB at 43 degrees C, numbers of lactose-positive Enterobacteriaceae decreased in most enrichments which resulted in a positive salmonella isolation, but remained constant in the majority of those that did not. Levels of lactose-negative Enterobacteriaceae did not decrease in most salmonella-positive tests, but did so in half of the salmonella-negative ones. In the salmonella-positive tests the numbers of salmonellas had increased to 10(3)-10(7)/ml in BPw and after transfer to TBB slowly reached 10(4)/ml or more. In all cases the numbers of salmonellas exceeded those of the competing flora on brilliant green agar (BGA). In the salmonella-negative tests the numbers of salmonellas had increased less in BPw and decreased in most of the TBB enrichments. In none of these negative tests did the numbers of salmonellas exceed those of the competing flora on BGA. Escherichia coli dominated in most of the salmonella-negative tests. The results suggest more influence of lactose-positive than lactose-negative Enterobacteriaceae on the detection of salmonellas. The effect of competing microorganisms seems to depend not only upon their initial numbers, but also upon the types that can interact with salmonellas during selective enrichment.

[Disorders in slaughtering animals. V. Endocarditis in slaughtering pigs, sows and cattle]. / Afwijkingen bij slachtdieren. V. Endocarditis bij slachtvarkens, zeugen en runderen.

Bacteriological studies were done in 673 slaughtered animals (pigs, sows and cattle) in which post-mortem examination had revealed the presence of endocarditis. The studies were positive for the presence of bacteria in 453 cases. Lesions were not observed on ante-mortem inspection in 386 cases. Isolation of Corynebacterium pyogenes was extremely common in cattle, whereas beta-haemolytic streptococci and Erysipelothrix insidiosa were very frequently isolated in slaughtered pigs.

[Lesions in slaughtered animals. IV. Decubital lesions in pigs (author's transl)]. / Afwijkingen bij slachtdieren. IV. Ligplekken bij varkens.

Bacteriological studies (bacteriological examination in conformity with Meat Inspection Regulations) were done in 315 pigs. Examination was positive for bacteria in 58.4 per cent of these slaughtered pigs. The likelihood of bacteriological examination being positive increased with the diameter of the decubital lesion, 39.8 per cent being positive when the diameter was less than 5 cm and 69.2 per cent being positive when the diameter was greater than or equal to 5 cm. In 95.1 per cent of the animals in which examination was positive for bacteria, C. pyogenes or haemolytic streptococci were isolated from the splenic tissues. The presence of a decubital lesion was usually associated with disturbances of locomotion in the slaughtered animal. Inflammatory lesions such as (poly)arthritis of the extremities and vertebral abscesses were frequently observed. Of twenty-six pigs showing a decubital lesion unaccompanied by other pathological findings, ten animals (38.5 per cent) were found to be positive on bacteriological examination. It is concluded that the presence of a decubital lesion in a slaughtered pig should be regarded as an objective criterion for bacteriological examination of the animal in question.

[Lesions in slaughtered animals. III. Multiple abscesses in pigs (author's transl)]. / Afwijkingen bij slachtdieren. III. Multiple abcessen bij varkens.

Bacteriological examinations in accordance with the Meat Inspection Regulations were made in pigs with multiple abscesses. The findings by six meat inspection services were collected. A total number of 2,380 pigs with multiple abscesses underwent bacteriological examination which was positive for bacteria in 778 cases (32.7 per cent). Bacteriological examination of pigs with multiple abscesses is recommended prior to pronouncing any verdict other than condemnation, particularly when conditional permission to slaughter has been granted.

[Lesions in slaughtered animals. II. Inflammation of the tail and embolic pneumonia in pigs (author's transl)]. / Afwijkingen bij slachtdieren. II. Ontstoken staart met een embolische pneumonie bij varkens.

In 4,724 fattening pigs with inflammation of the tail and embolic pneumonia, a bacteriological examination was made in accordance with the Meat Inspection Regulations. The results of bacteriological examination were positive in 1,248 (26.4 per cent) of these animals. It is recommended consistently to make a bacteriological examination in animals showing these lesions. Any verdict by the inspector, other than condemnation, can only be rendered following bacteriological examination carried out in conformity with the Meat Inspection Regulations.

[Studies for the presence of Salmonella in the bone marrow of normal slaughtered pigs (author's transl)]. / Onderzoek naar het voorkomen van salmonella in het beenmerg bij normale slachtvarkens.

Of sixty pigs in which the tonsils, mesenteric lymph nodes, caecal contents, liver and bile, urinary bladder and bone marrow were examined for the presence of Salmonella, thirty-six (60 per cent) were found to be positive. The results were as follows: tonsils alone one, mesenteric lymph nodes alone five, tonsils plus mesenteric lymph nodes two, mesenteric lymph nodes plus caecal contents seven, tonsils plus caecal contents six, tonsils plus mesenteric lymph nodes plus caecal contents six, caecal contents plus liver and bile one, mesenteric lymph nodes plus caecal contents plus liver and bile one. Salmonella was not found to be present in the urinary bladder and bone marrow. It is oncluded that in the manufacture of "meat" (muscular tissue obtained by scraping bones), the bone marrow fraction does not contribute to contamination of this meat with Salmonella. Of the total number of seventy-eight strains isolated, fifty-two were of the sero-type S. typhimurium (66 2/3 per cent).

[Studies for the presence of Yersinia enterocolitica and Yersinia pseudotuberculosis in clinically normal pigs (author's transl)]. / Een onderzoek naar het voorkomen van Yersinia enterocolitica en Yersinia pseudotuberculosis bij klinisch normale varkens

163 clinically normal slaughtered pigs were examined for the presence of Yersinia enterocolitica and Yersinia pseudotuberculosis. The following results were obtained: Yersinia enterocolitica was isolated from the tonsils in twenty-two cases, Yersinia pseudotuberculosis being found to be present in the tonsils in seven cases, Yersinia enterolitica was isolated from the liver in one case and from the caecal contents in eight cases, and Yersinia pseudotuberculosis was isolated from the caecal contents in three cases. These bacteria were not isolated from the mesenteric lymph nodes and muscle tissues. All sixty samples of minced raw pork which were examined, were also negative for these micro-organisms. Almost all strains isolated were of the same serotypes as those isolated from man in the Netherlands. The findings did not suggest that ingestion of raw pork might involve a risk of human yersiniasis. It is doubted, however, whether the methods of isolation were sufficiently selective.

[Investigation of the incidence of Salmonella in the Faeces, mesenteric lymph glands, and intestinal wall (Peyer's patches) of normal pig carcases (author's transl)]. / Onderzoek naar het voorkomen van Salmonella in faeces, mesenteriale lymfklieren en darmwand (Peyerse plaques) bij normale slachtvarkens

The faeces, mesenteric lymph glands, and intestinal wall (Peyer's patches) of two hundred clinically normal pig carcases were examined. Of these, 115 (57.5%) were found to infected with Salmonella in the following combinations: lymph glands only, 6; intestines only, 14; faeces only, 13; lymph glands + intestines, 7; lymph glands + faeces, 11; intestines + faeces, 20; lymph glands + intestines + faeces, 44. The supposition that Salmonella can be detected in the lymphoid tissue of the intestine (Peyer's patches) far more frequently than in the faeces was not confirmed. The presumably still rising number of clinically healthy butcher's pig which are actually infected with Salmonella is pointed out.