Dog overpopulation and diagnosis of intestinal parasites on Santa Cruz Island, Galapagos 2016

Dog overpopulation and diseases are hazards to native island species and humans on the Galapagos. The main objective of the study reported here was to estimate the observed human:dog ratio on Santa Cruz Island, Galapagos in September 2016. In addition, dog demographic data were used to model the expected annual dog population growth in the next 10 years. A secondary objective was to measure the burden of dogs infected with intestinal parasites. The observed human:dog ratio was 964:202 (or 4.77:1), which extrapolates to 3290 dogs; an increase of 31% in the dog population on Santa Cruz from 2014 to 2016. Study results show that current spay-neuter efforts (about 300 dogs per year; 60% females, 40% males) are not enough to keep the population stable (i.e., current baseline of 3290 dogs). The frequency of dogs infected with Ancylostoma spp., an intestinal parasite in dogs that can cause cutaneous larval migrans in humans, was 18/44 or 41% (95% CI = 27%, 55%). These results provide the most complete assessment of the dog overpopulation on the Galapagos to date.