Ecoepidemiology and zoonotic risk of intestinal parasites in humans and domestic dogs in marginalized coastal communities of Ecuador.

Intestinal parasites are a global public health concern, affecting both humans and animals, particularly in neglected and underserved communities. These parasites can lead to severe health complications and have zoonotic potential, especially in areas with close human-animal interactions and poor sanitation. This study investigates the ecoepidemiology and zoonotic relationship of intestinal parasites in humans and their domestic dogs in marginalized urban and rural sectors of the Ecuadorian coast. A total of 500 domestic dogs and 160 human participants from four neglected areas of Guayas province were studied between April and October 2024. Fecal samples were collected and analyzed using coproparasitic techniques (direct, flotation, sedimentation, and modified Baermann), followed by morphometric confirmation. Sociodemographic surveys, environmental assessments, and epidemiological indicators were also collected. Statistical analyses, including chi-square tests and logistic regression models, were used to identify associations between parasite prevalence and socioenvironmental variables. The overall prevalence of intestinal parasites was 31.87% in humans and 78% in domestic dogs. The most common parasites in humans were Entamoeba coli (18.13%), Entamoeba. histolytica (10%), and Hymenolepis nana (3.75%). In dogs, Ancylostoma caninum (53.6%), Taenia spp. (Echinococcus granulosus) (15.2%) and Toxocara canis (12.4%), were the most prevalent. Zoonotic parasitic diseases identified included cutaneous larva migrans, hydatidosis, and strongyloidiasis. Significant associations were found between parasitic infections and factors such as water source, sanitation infrastructure, barefoot walking, and peridomiciliary habitat of dogs. The findings highlight a high burden of intestinal parasitism in both humans and dogs in neglected coastal communities of Ecuador, driven by inadequate sanitation, poor socioeconomic conditions, and environmental risk factors. The study underscores the need for integrated One Health approaches, including education, improved hygiene, and routine deworming, to prevent zoonotic transmission and improve public health outcomes.