Spatiotemporal overlap and contact rates among small Indian mongooses and free-roaming domestic dogs in Puerto Rico: Implications for rabies virus transmission

Small Indian mongooses (Urva auropunctata) are the primary terrestrial wildlife rabies reservoir on Puerto Rico, the Dominican Republic, Cuba and Grenada, where they represent a risk to public health through direct human exposure and through transmission of rabies virus to domestic animals that have close association with humans. Historically rabies virus was introduced via domestic dogs and then later shifted into mongoose populations on Puerto Rico and other islands, yet domestic dog-mongoose ecological interactions have been understudied throughout the Caribbean. In this study, we derived daily activity patterns from baited camera traps, and investigated the use of proximity and GPS tracking data acquired concomitantly from mongooses and free-ranging domestic dogs (FRDD) to characterise intra- and interspecific contacts and estimate contact rates. Our results highlight that although mongooses and FRDD are both relatively active in late afternoon, close interspecific contacts only occurred among 4% of collared mongoose-dog dyads, were infrequent (range: 0 - 0.19; median = 0 contacts per day), and were spatially restricted to road and forest edges. Mongooses were only documented to contact feral FRDD, whereas no mongoose contacts with stray FRDD were detected. The space use by stray FRDD and association to humans may play a role in limiting direct contacts with mongooses and the associated risks of rabies virus cross-species transmission. Intraspecific contacts were documented among 11% of collared mongoose-mongoose dyads, occurred at a rate ranging between 0 - 0.57 (median = 0) contacts per day, and took place within wildlands. Intraspecific contacts were documented among 30% of collared dog dyads, at rates ranging between 0 - 3.37 (median = 0) contacts per day, which was more frequent contact than observed for collared mongooses ({chi}2 = 8.84; DF =2; P = 0.012). All dog-dog contacts occurred in proximity to human residential development and involved both stray-stray and stray-feral FRDD collared dyads. Feral FRDD may represent a rabies virus vector between mongooses and FRDD living close to humans. Home range overlap was a significant predictor of contact rates (P < 0.001) among intra- and interspecific dyads of both species and may represent a useful proxy for contact between species that also overlap in daily activity patterns. Transitional areas between wildlands and human residential development could represent hotspots for infectious disease transmission between mongooses and feral FRDDs. Characterization and quantification of contact rates in mongooses and FRDDs across the wildland-urban gradient across wet and dry seasons could help to inform animal rabies control strategies on Puerto Rico and other Caribbean islands with enzootic mongoose rabies.