Gastrointestinal and cardiopulmonary parasites in canines and felines of the Azores Islands - Portugal

Insular territories offer several biotic and abiotic conditions conductive for the spread of gastrointestinal (GI) parasites in companion animals, as well as their transmission to humans. However, information regarding this topic is still scarce. The present study aimed to determine the prevalence and intensity of GI and cardiopulmonary (CP) parasites, as well as to evaluate risk factors associated with the occurrence of parasitic infections, in dogs and cats from the Azores archipelago (Portugal). Fecal samples were gathered from cats (n = 885 samples) and dogs (n = 910). Blood samples were collected from 215 cats and 205 dogs. Also, a questionnaire was filled out in order to determine predisposing factors and to establish a scale for companion animals, which compares the manifestation of clinical signs to the parasitic burden of the infected animal. All fecal samples underwent processing through qualitative (Willis flotation, Baermann) and quantitative (Mini-FLOTAC) coprological techniques, whereas all blood samples were analyzed using the modified Knott method and the commercial Witness® Dirofilaria serological assay. The overall prevalence of GI parasitism in dog feces was 59%: Ancylostomatidae (37%), Toxocara canis (22%), Trichuris vulpis (16%) and Cystoisospora spp. (9%). In cats, the overall prevalence of GI parasitism was 61%: Ancylostomatidae (39%), Toxocara cati (22%), Cystoisospora spp. (9%) and Trichuris sp. (0.1%). CP parasites were only detected in cat feces (16% prevalence), positive for Aelurostrongylus abstrusus. Blood samples were negative for CP parasitism, in both hosts. In canine feces, Ancylostomatidae showed higher egg counts (317 ± 24 EPG), followed by T. canis (79 ± 8 EPG), Cystoisospora spp. (42 ± 7 OPG) and T. vulpis (41 ± 5 EPG). In feline feces, parasitic intensity was higher for Ancylostomatidae (349 ± 25 EPG), followed by T. cati (108 ± 11 EPG), Cystoisospora spp. (64 ± 9 OPG), A. abstrusus (8 ± 1 LPG) and Trichuris sp. (0.01 ± 0.006 EPG). In both species, risk factors associated with the presence of parasitism were mixed breed, shelter environment, outdoor access, cohabitation with other animals and infrequent deworming of animals. For both hosts, the manifestation of clinical signs occurred for parasite shedding higher than 800 EPG/OPG/LPG (levels 3 and 4). Animals ranked as level 1 (up to 300 EPG/OPG/LPG) were often asymptomatic. The current research is the first to entail on GI and CP parasites in companion animals from the nine islands of the Azores archipelago, demonstrating that these parasites are common in companion animals from this insular region and that Azorean populations are at risk of exposure to potentially zoonotic parasitic agents. The present study also proposed the first rating scale that associates parasitic intensity with the presence/absence of clinical signs, in dogs and cats.