An Association of Human Reaction to Intradermal Toxoplasmin with Degree of Animal Contact and Rural Residence

Schnurrenberger, Paul R.; Tjalma, Richard A.; Wentworth, Frederick H.; Wentworth, Berttina B.

doi:10.4269/ajtmh.1964.13.281

Cited by 9 publications

(2 citation statements)

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“…In the first two studies the risks of toxoplasmosis were compared between veterinary and medical students. 35 36 The veterinary students were more often skin test positive, but if their more prevalent rural residence was considered, the difference in positivity between the groups disappeared. Small animal practitioners in San Fransisco37 and Canada38 had no more antibodies than the population at large37 or a selected control group.38 Furthermore, no differences were found between veterinarians, other workers with an occupational cat and dog contact, and a non-veterinarian control group with no occupational animal contacts.39 When students and personnel in veterinary colleges in California and Brazil were compared, the Brazilians were twice as often positive but no particular species of animals could be incriminated.…”

Section: Discussionmentioning

confidence: 96%

Contact with pigs and cats associated with high prevalence of Toxoplasma antibodies among farmers.

Seuri

Koskela²

1992

Occupational and Environmental Medicine

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Antibodies to Toxoplasma were measured by enzyme linked immunosorbent assay (ELISA) in sera from 159 abattoir workers, 142 pig farmers, and 106 grain or berry farmers. Farmers occupationally exposed to pigs had antibodies in 53 (37%) cases, abattoir workers in 40 (25%) cases, and farmers not exposed to pigs in 24 (23%) cases. In each group antibodies were more prevalent among those who had a cat or cats in the household. Controlling for age and cat contacts changed the prevalences less than one percent. The results indicate that pig farmers might have an occupational risk of toxoplasmosis. As the prevalence of antibodies among abattoir workers was about the same as among the referent farmers, it seems unlikely that infection from Toxoplasma could be acquired by mere handling of raw meat.The Toxoplasma parasite infects many animal species. In humans, the infection is usually subclinical and in symptomatic cases the diagnosis is often missed.' After the primary infection, viable Toxoplasma cysts probably persist throughout life.2 Toxoplasma has a worldwide distribution. The prevalence of infection among adults varies greatly in different populations; up to 90% are infected in Paris and up to 50% in the United States.3 Humans are known to be infected by at least three routes: transplacental infection in congenital transmission,4 infection by the cyst through ingestion of raw meat,5 6 and infection by the oocyst from contact with infected cats or exposure to contaminated soil.' 78 Routes of infection may vary, depending on hygienic and social factors, on humidity, and on occupations, manners, and customs of inhabitants.9 10Although cats are considered to play a central part in the spreading of toxoplasmosis,'178 11 several epidemiological studies,9 1217 including some in Scandinavia,'>20 have failed to show increased prevalence of antibodies among those in contact with cats.Toxoplasma infection is highly prevalent in swine in many countries,21, but the prevalence ofantibodies to Toxoplasma in slaughtered pigs in Finland is only about 2-5% as measured by ELISA.22 We studied the prevalence of antibodies to Toxoplasma among pig farmers, grain or berry raising farmers, and abattoir workers to find possible associations with cat and pig contacts. Materials and methodsWorkers from the killing floor of six pig processing abattoirs situated in central and northern Finland were asked to participate. In today's Finnish abattoirs these workers use bare hands in contact with the flesh of the carcasses. For the sake of hygiene the use of gloves, customary for other jobs in meat processing plants, is forbidden in work on the killing floor. A total of 177 workers were asked to fill in a questionnaire and to give a blood sample for antibody testing; 159 (90%) blood samples were obtained from the abattoir workers.Similar questions were sent to 270 pig farmers and 310 farmers whose first or second line of production was either grain or berry raising. The grain or berry farmers were not involved in meat production and live...

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Section: Discussionmentioning

confidence: 96%

Contact with pigs and cats associated with high prevalence of Toxoplasma antibodies among farmers.

Seuri

Koskela²

1992

Occupational and Environmental Medicine

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“…The difficulties of properly conducting such a statistical study in uveitis are emphasized by the epidemio¬ logie examination in 1,357 normal patients, which showed not only the importance of animal contact-students of medicine had significantly lower incidence of dye test titer than did students of veterinary medicine-but also the importance of such factors as city vs rural environment. 66 The excellent uveitis study previously cited 65 made every attempt to control both age and geographical representation, and it is important that such a carefully done study has confirmed other statistical surveys of the high incidence of antibody to toxoplasmosis in posterior chorioretinal disease.67 A variety of different methods 68·69 can be used for the epidemiological study of toxo¬ plasmosis, but serological testing cannot make a diagnosis of uveitis in a specific pa¬ tient. We must agree that "the Toxoplasma dye test is an effective aid in the study of the participation of toxoplasmosis in the etiology of some eye diseases.…”

Section: Toxoplasmosismentioning

confidence: 99%