SUMMARYA sero-epidemiological survey, using an indirect immunofluorescence test for IgG against Coxiella burnetii (phase II), was carried out in the Netherlands. Serum samples taken in 1968, 1975,1979 and 1983 were tested. Occupational groups with a supposedly high risk of infection (veterinarians, residents of dairy farms and taxidermists) showed a significantly higher percentage of seropositives than defined controls. The percentage of seropositive amateur wool spinners was significantly higher than that ofthe controls from the same region. Since 1968 there has been no increase in the percentage ofinfected persons, indicating that, contrary to earlier assumptions, Q fever has been endemic in The Netherlands for a long time already. The increase in numbers ofnotified cases ofovert Q fever is considered to be the result of the recent introduction of a sensitive indirect immunofluorescence test for IgM antibodies against C. burnetii. Antibody percentages in all age classes between 1 and 64 years were much alike, suggesting that most infections occur in early childhood. This is in accordance with the finding that 35 % of our patients are younger than 3 years. The possibility of infection related to childbirth and lactation is discussed.

Of a total of 1445 sows, tumors were detected in the uterus of 11 animals and in the cervix/vagina of 1 animal. Tumor-like lesions were detected in the ovary of 56 animals. The incidence of tumors was higher than that mentioned in the literature, possibly because of the relatively high age of the sows (mean parity of 6.8) and the accuracy of investigation. Several tumors would not have been detected during routine slaughter examination. The uterine tumors were diagnosed as leiomyoma (6), fibroma (3), cyst-adenoma (1) and fibro-leiomyoma (1). The cervical/vaginal tumor appeared to be a fibroma. The ovarian lesions could not be satisfactorily classified. They consisted of connective tissue, blood vessels, and granulosa cells, which were present in variable quantities in different ovaries and in different sides of the same ovary. Sows with tumors were older than the mean determined age at slaughter (parity 6.8). Sows with uterine and cervical/vaginal tumors had a parity of 11.6; sows with ovarian lesions had a parity of 9.0. Sows with uterine- or a cervical/vaginal tumor were often slaughtered for infertility reasons.

The effect of the indurative lymphocytic mastitis caused by infection with maedi-visna virus was quantified by comparing the pre-weaning growth of lambs from infected and uninfected ewes under the same conditions. A total of 73 infected, but clinically healthy, ewes and 75 ewes from a maedi-visna virus-free source were purchased to form a new flock; they were all three years old. The ewes were mated and the flock was managed as a normal field flock. Serum samples were taken at regular intervals and tested for antibodies to maedi-visna virus. The lambs were weighed at birth and at 14, 30, 50 and, finally, 80 days old, when they were weaned. The ewes were slaughtered, their udders were examined histologically, and the lesions were assessed by counting the typical lymphocytic follicles. Sixty-six per cent of the ewes that were seropositive at slaughter appeared to have follicles. A statistically significant association was found between the number of follicles in the udder and the reduction in the growth rate of the lambs. Lambs from ewes with the mean number of follicles weighed 1.7 kg less at weaning.

Sheep in a flock in which 88 per cent of the ewes had antibodies to maedi-visna virus were clinically examined for udder induration during lactation and after drying off. On both occasions about half of the ewes had indurated udders. Histological examination revealed lymphocytic mastitis associated with maedi-visna virus infection, in the udders of six of 25 hoggs (24 per cent), 21 of 39 shearlings (53.8 per cent) and 42 of 67 ewes (62.7 per cent). Distinct lung lesions were found in 8 per cent of the hoggs, 12.5 per cent of the shearlings and 10 per cent of the ewes. The results of a clinical examination of dry udders were correlated with the histological findings.

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