I Serological evidence for the presence of Bruce& antibodies in sheep and goats on

A serological survey for Brucella antibodies in sheep and goats was completed on Saint Croix, United States Virgin Islands (USVI). Seroprevalence (at suspect or reactor titer levels) for B. melitensis antibodies was 11.3% for sheep and 2.5% for goats. This is the first report, of which we are aware, of B. melitensis antibodies in sheep or goats in the Caribbean islands.


INTRODUCTION
Brucela melitensis, a zoonotic disease, is usually carried by goats and sheep, although it is the least host-specific of the brucellosis-causing organisms. B. mehtensis is well known in many developing and some developed nations. For example, this organism is known to occur in Egypt (4) Syria (1 l), Israel (6), India (2), Saudi Arabia (13), and sub-Saharan Africa (1,5,12). In the New World, it has been reported from Argentina, Peru, and Mexico (7). 13. mehtensis is not known to occur in the Caribbean islands. However, many sheep and goats were brought to this area from Old World countries known to have 13. melitensis. With no specific Brucella surveillance efforts aimed at sheep and goats, it is possible that the bacteria were brought to the New World with their hosts and established in the region. This seroprevalence survey is an attempt to determine if fut-ther studies might be warranted.
both rolling hills and level terrain which makes it more suitable for agriculture.
Food animal agriculture includes dairy and beef cattle and an even larger population of sheep and goats. Most sheep and goats are maintained as backyard animals, tethered or fenced in small pastures or paddocks, usually in groups of fewer than 30 animals. Sheep and goats are often kept in the same enclosure.
The goat sera for this study were collected when goats were treated with anthelmintics or otherwise attended by a veterinarian from the USVI Depar-tment of Agriculture. The sheep included in this study were all from the University of the Virgin Islands (UVI) Agricultural Experiment Station flock. This flock was formed during 1985-87 by purchasing local sheep from several flocks on Saint Croix. The sheep have been kept together in the same corrals and pastures during the 2 years prior to this study.
Sera from a total of 161 goats from 9 herds were collected. Sera were obtained from 53 sheep in the UVI flock, representing 5 original flocks plus several sheep born into the UVI flock. The sera were frozen and shipped to the National Veterinary Services Laboratories in Ames, Iowa, for serological testing. Each sample was tested for 13. ovis antibody by the complement fixation test (9), for B. abortus antibody by the standard plate test, and for B. melitensis antibody by the standard tube test (14).
A.S. Ah1 P.C. Bartlett W.M. Frerichs Titers were measured and interpreted as suspicious of a previous infection (suspect) or as evidence of previous infection (reactor) as outlined in tables I and II.

RESULTS AND DISCUSSION
Four goats from 3 herds in 3 different areas of Saint Croix showed B. melifensis antibodies, with suspect or reactor titers. This gives a seroprevalence of 4/161 or 0.0248. Three of 9 herds had at least one goat with a reactor or suspect titer for a herd prevalence of 33 %. Map 1 shows locations of the herds from which animals were sampled. The location of these animals, titers, and interpretation of the titers are given in table 1.
All goats were negative for B. ovis antibodies. One goat showed a B. abortus titer, incomplete at 1 :50, which could be interpreted as a borderline suspect for previous infection with B.abortus or could possibly represent a cross-reaction with B. melitensis.
Of the 53 sheep tested, 6 showed titers high enough to use as evidence of previous infection with B. melitensis. One showed a 2+ titer at 1 :lO for B. ovis; this animal originated in a flock at location H (map 1). Antibodies for B.

CONCLUSION
From a sample of sheep and goats on Saint Croix, we have found serological evidence for previous infection with B. melitensis for both species. It is possible that these titers represent cross-reactivity with other antigens. More definitive methods for diagnosis of B. melifensis in sheep and goats must be undertaken before the question of occurrence cari be settled (3, 10).
On Saint Croix, the other Virgin Islands, and most of the Caribbean islands as well, sheep and goat owners live in close proximity to their animals and often practice backyard slaughter of animals for home consumption. If B. mehtensis does occur in these animals, it would not be surprising to find cases of human brucellosis as well. The need for a comprehensive study of this agent in sheep and goats is suggested by the results of this serological survey.