Intestinal parasitic infections: risk factors and zoonotic aspects in human and dog populations of a rural area of Piaui State, Brazil

Intestinal Parasitic Infections (IPIs) are prevalent in vulnerable populations, yet zoonotic transmission is underreported. This study analyzed, under the One Health approach, the prevalence of and risk factors for IPIs among humans and dogs in a rural region of Teresina, Piauí, Brazil. A total of 361 human fecal samples, 23 household dog fecal samples and 81 dog fecal samples collected from public roads were analyzed using the Lutz, Baermann and Kato-Katz methods. Anthropometric measurements, haemoglobin levels in children aged 5 to 14 and a survey of cases of cutaneous larva migrans (CLM) were also analyzed. The height and weight of these individuals were used to calculate Z-scores for height-for-age (HAZ), weight-for-age (WAZ) and weight-for-height (WHZ). Associations between parasites and risk factors were assessed using Pearson's chi-square test, Student's t-test and logistic regression. The results showed that 47,9% (173/361) of the residents were parasitized, being 42,9% (155/361) by protozoa and 9,4% (34/361) by helminths. The most common pathogenic protozoa were Giardia duodenalis (8.3%; 30/361) and Entamoeba histolytica/dispar (5.3%, 19/361), while the most pathogenic helminths were Ascaris lumbricoides (6.6%, 24/361) and hookworms (4.7%, 17/361). Analysis of nutritional status revealed that 3.1% of children and adolescents had short stature (HAZ<-2), 7.3% had low weight (WAZ<-2) and 21.9% had anemia (hemoglobin <11.5g/dL). Mean HAZ was significantly lower in children with ascariasis (-1.16±0.24 vs. -0.34±0.10; p=0.008) and hookworm (-1.28±0.33 vs. -0.39±0.09; p=0.041). Hookworms were the most frequent parasites in dog feces (62.5%, 65/104). Infections by Toxocara spp. and Trichuris spp. were observed in dogs, with 3.8% of the samples presenting mixed infections. Cases of CLM were identified (n=45/361), with 62.2% of the cases in children (2 to 9 years) and a predominance for males (68.8%). These data highlight the intersections between IPIs in humans and dogs and reinforce the need for intersectoral and integrated health promotion measures. The adoption of the One Health approach could strengthen surveillance and prevention of zoonoses and contribute to public policies aimed at improving the quality of life in vulnerable areas.