A serologic survey of horses in the New Jersey-Pennsylvania area demonstrated that about 10% (6.2-14.2%) have significant levels of serum antibody to Borrelia burgdorferi. However, in a highly endemic area of central New Jersey, up to 60% of the mares and yearlings samples on one farm were seropositive. In 1983, sera from this same farm exhibited only 12% positives in mares and 35% positives in yearlings. Longitudinal studies of paired sera obtained from individual yearlings over a 6-month period in 1985 showed that 34% of them declined during the period. A new clinical syndrome associated with this farm has been observed in 1985-87. In 1985 only an edema of the legs and a dermatitis were noted, in 19.2% of the foals. There was a clustering of cases on one site, where one peer group of foals was sequestered after weaning, which suggested a point source of infection other than arthropods. In 1986, 14.6% of the foals were affected, four of them with arthritis, two of which resisted antibiotic treatment for over several months' time. Experimental infection of a pony with triturated B. burgdorferi infected tick material indicated low specific antibody levels starting about the ninth day that continued for a 3-week period. When this animal was challenged 6 months later with primary B. burgdorferi cultures, a rapid and significant booster effect was evidenced within 4 days.

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Slight modifications of a small, plastic covered greenhouse provided a chamber for the exposure of cattle of all ages to aerosols of foot-and-mouth disease virus. Particle size distributions of aerosols were 76% less than 3 microns, 17% 3-6 microns, and 7% greater than 6 microns immediately after the deVilbis no. 40 nebulizer used was turned off and 90% less than 3 microns, 8% 3-6 microns, and 2% greater than 6 microns 20-30 min later. Pharyngeal virus growth curves and viremia patterns correlated well with the dose of virus to which test cattle were exposed and were similar to those of cattle inoculated intranasally.