The importance of the dog (Canis lupus familiaris) in cocoa farms as carriers of helminths potentially transmissible to humans and wildlife in the Southern Bahia, Brazil

ABSTRACT: Domestic dogs (Canis lupus familiaris) can be considered an invasive species as they have been introduced by humans in different parts of the world and represent a risk to wildlife conservation. Large extensions of agroforestry systems, where cocoa is grown under the shade of native trees, contribute to wildlife conservation in southern Bahia, Brazil. However, this system can increase contact between species of the native fauna and domestic dogs, which are frequently taken to the fields by rural workers. The aims of this study were to investigate the presence of domestic dogs inside cocoa agroforestry systems and the occurrence of helminths in dogs from cocoa farms near two protected areas: the Una Biological Reserve (REBIO-Una) and the Serra das Lontras National Park in Una, Bahia. We also investigated general characteristics of the dogs such as age, sex, breed, feeding frequency, vaccination, deworming and others, and evaluated possible risks of wildlife and human contamination by the domestic dog parasites. Camera traps were set up on eight cocoa agroforestry systems and three adjacent forest fragments. For parasitological investigation, fecal samples were collected from domestic dogs that lived on the eight cocoa farms. A total of 539 photos of 12 mammals were registered, of which 15% were of domestic dogs. The parasitological research was carried out with fecal samples from 32 of the 39 dogs that lived in the cocoa farms. We found one genus of cestode, Dipylidium sp. (7.7%), and five genera of nematodes, Ancylostoma sp. (80.7%), Strongyloides sp. (38.4%), Toxocara sp. (30.7%), Spirocerca sp. (15.4%) and Trichuris sp. (11.5%). Regarding animal care, all dogs were in poor body condition, 49% were fed twice a day, 90% defecated in the forest or cocoa agroforestry systems, only 33% were periodically dewormed, 64% were vaccinated against rabies in less than 12 months, and only one dog was vaccinated against other viruses. The results showed that domestic dogs share the same environment as wild animals yet lack some basic health care, increasing the possibility of parasitic transmission between domestic dogs, wildlife and humans from environmental contamination. We highlight the need for responsible pet ownership and the monitoring the health of wild animals and the human population living in this region.