Intestinal parasites in dogs and their association with clinical manifestations of canine visceral leishmaniasis.

Dogs are companion animals commonly present in spaces shared with humans. However, this close contact may facilitate the transmission of zoonoses, such as canine visceral leishmaniasis (CVL). Additionally, dogs are potential hosts of endoparasites that can influence the clinical manifestations of CVL due to immunological interference occurring in parasitic coinfections. This study aimed to investigate the occurrence of endoparasites in domestic dogs seropositive for CVL and associate their clinical manifestations with the presence of intestinal helminths. We analyzed 47 seropositive dogs (51.06 % males; 48.9 % females; 80.8 % of undefined breed) that underwent clinical examination, blood count, euthanasia, necropsy, and coproparasitological diagnosis. Dogs were grouped into three clinical categories: low (40.4 %), medium (34.0 %), and severe (25.5 %) based on a modified version of the LeishVet clinical staging system. Coproparasitological results indicated Ancylostoma sp. and Giardia sp. as the most prevalent. Based on necropsy, Ancylostoma sp. and Dipylidium caninum were the most common helminths. Dogs with CVL and intestinal helminths frequently had macrocytic hypochromic (p = 0.0455) and microcytic hypochromic (p = 0.01963) anemia. We also found that Ancylostoma sp. was associated with more severe CVL clinical staging (odds ratio [OR] = 3.3621; 95 % confidence interval [CI] = 2.6413-4.2796) and negatively associated with red blood cell counts (OR = 0.9278; CI = 0.8702-0.9893). We conclude that intestinal helminth infections in dogs with CVL may represent an important aggravating factor for the disease's clinical progression.