Disappearance Rates of a Placebo Bait for the Small Indian Mongoose Across Different Habitats on St. Kitts

Abstract

The small Indian mongoose (Urva aurpunctata) is a non-indigenous wildlife reservoir for rabies virus on several Caribbean islands. Oral rabies vaccination (ORV) has been suggested to prevent the spread of rabies in mongooses, but there are limited data on ORV bait survival in maritime/tropical climates. We compared disappearance rates of an egg-flavored bait block vs. a control (canned tuna) and for bait blocks, we assessed if season, habitat, and day/night would influence the disappearance rate. On the island of St. Kitts, West Indies, we baited 45 stations (n=35 bait blocks, n=10 controls) at dawn and checked them twice daily for 4 consecutive days. This procedure was repeated after a two-day period, for each combination of season (dry and wet) and habitat type (mixed grassland, littoral and dry forest). We used the Kaplan-Meier method to estimate bait survival at 12 and 36 hours after baiting. Across all sites, control baits were removed faster than bait blocks, but by 36 hours, over 90% of all baits had disappeared. For bait blocks only, the disappearance rate was higher during the dry season and in the dry forest habitat compared to the other habitats. There was no difference between diurnal and nocturnal disappearance rates. While the exact species that consumed the baits remain uncertain, we found that mongooses readily remove bait blocks, along with non-native mammals (e.g., dogs and cats) and land crabs in littoral habitats. We suggest that the bait blocks used in this study may be suitable for use as an external bait matrix for ORV baits.