Flea infestations in companion animals: Challenges in heterogeneous subtropical environments

Fleas are important for their role as parasites causing pulicosis or tungiasis, and as vectors of pathogens that can cause diseases in humans and other animals, in tropical and subtropical regions, with a disproportionate effect linked to contexts of structural poverty and social exclusion. This study evaluated the risk factors for flea parasitism in dogs and cats from urban (Ur) and rural (Ru) households in Puerto Iguazú, Argentina, through seasonal sampling between March 2017 and February 2018. Prevalence (P), mean intensity, and mean abundance of the host-associated variable were calculated. To identify associations between the presence/pseudoabsence of fleas and the explanatory variables, a generalized linear mixed model was constructed. A total of 1932 fleas, identified as Ctenocephalides felis felis (Bouché) (Siphonaptera: Pulicidae), were collected from 402 dogs (P_Ur = 79.8%; P_Ru = 88.4%) and 87 cats (P_Ur = 77.6%; P_Ru = 66.7%). The prevalence was higher in rural dogs. Regarding host species, the prevalence in dogs was higher than in cats in rural areas. Tunga penetrans L. (Siphonaptera: Tungidae) was observed in 195 dogs (P_Ur = 31.97%; P_Ru = 70.48%) and 29 cats (P_Ur = 4.46%; P_Ru = 59.46%), which was also more common in rural areas. Risk factors for C. f. felis presence in dogs included young age, lack of antiparasitic treatment, peridomestic fumigation, bare soil and lower humidity and temperature four weeks prior to sampling (w-4). In cats, infestation was associated with young age, the presence of infested dogs in the same household, and higher vegetation coverage. In both hosts, T. penetrans infestation was positively associated with no antiparasitic treatment, lower humidity in w-3, and higher humidity in w-1 and higher temperature in w-2. The findings indicate that the factors influencing the presence, prevalence and abundance of C. f. felis and T. penetrans may differ according to host, socio-environmental, climatic and soil conditions in each locality. The establishment of institutional policies is imperative to effectively manage flea parasitosis, particularly in regions of socio-environmental heterogeneity.