National Seroprevalence and Risk Factors for Zoonotic Toxocara spp. Infection

Abstract

To estimate the prevalence of Toxocara spp. infection in a representative sample of the United States population >or= 6 years of age, sera from participants in the Third National Health and Nutrition Examination Survey (1988-1994) were tested for antibodies to Toxocara. Among the 30,930 persons selected for the survey, 82% (N = 25,733) were interviewed, and 91% (N = 23,527) of those interviewed underwent physical examination of which 87% (N = 20,395) were tested. The age adjusted Toxocara seroprevalence was 13.9% (95% confidence intervals [CI] 12.5, 15.3), and was higher in non-Hispanic blacks (21.2%) than non-Hispanic whites (12%) or Mexican Americans (10.7%; P < 0.001). Increased Toxocara seropositivity was associated with head of household level of education (low versus high) (odds ratio [OR]: 2.2; CI: 1.8, 2.8), poverty (OR: 1.5; CI: 1.3, 1.8), elevated blood lead concentrations (OR: 1.4; CI: 1.1, 1.9), and dog ownership (OR: 1.2; CI: 1.1, 1.4). Toxocara infection is widespread and associated with specific risk groups.

Toxocariasis in the Americas: Burden and Disease Control

“…These observations correlate with the findings of Radman et al in their study of 156 patients from the city of La Plata, in which 38 of the 61 patients with positive ELISA were under 15 years [52]. However, in most studies, there has been no significant difference in age and the relationship with positive T. canis seroprevalence [7]. The same was demonstrated in a study in General Mansilla, a rural town located 96 km from Buenos Aires, where the frequency of toxocariasis was 23 % (23/100), with 17 people under 14 years and six people over this age; however, the difference was not significant [53,54].…”

“…The prevalence rate of toxocariasis, which is based on serologic studies that measure antibodies to T. canis antigens, among inner city blacks living in Connecticut cities was found to be 10 % and even higher among inner city Hispanics [12]. The prevalence among socioeconomically disadvantaged blacks in the American South was as high as 30 % between 1971 and 1973 [13]; however, it was recently estimated that approximately 21 % of blacks are seropositive [14]. So, based on the estimate that 13.3 million impoverished blacks live in America [15], with prevalence estimates between 10 % and 21 %, as many as 1.3 million to 2.8 million individuals may be exposed or infected, making this disease one of the most common infections among any underrepresented minority group [9].…”

People, Pets, and Parasites: One Health Surveillance in Southeastern Saskatchewan

“…21 This low human sero-prevalence may reflect the fact that many dogs defecated in surrounding bush areas, and thus were less likely to contaminate human environments through parasite eggs in their feces. As well, extremely cold winter conditions may also decrease the human risk of exposure to some infective parasite eggs from dog feces.…”

Anti-Toxocara spp. antibodies in an adult healthy population: serosurvey and risk factors in Southeast Brazil

“…Socioeconomic status has been shown to influence the risk of human infection with Toxocara spp. Infections are more prevalent in populations at low socioeconomic levels, characterised by a low education level of the head of household and decreased family income due to poor sanitation and water quality [10,24] . Populations living in rural and poverty areas are more likely to become infected by toxocariasis agents as a consequence of an increased number of dogs in the household or the environmental conditions that allow the maintenance of eggs in the soil [8,25,26] .…”