A Survey of Environmental Contamination with Ascarid Ova, Wallingford, Connecticut

Abstract

Few studies have been conducted in the United States to quantify the potential risk associated with encountering zoonotic ascarid ova in the environment. In an effort to raise awareness and to better understand the risk of acquiring visceral larva migrans in south central Connecticut, this environmental survey was conducted to determine the prevalence of ascarid ova (Toxocara canis, Toxocara cati, Baylisascaris columnaris, and Baylisascaris procyonis) in public areas of Wallingford, Connecticut, to compare prevalence levels among these public areas, and to determine what host species are primarily responsible for environmental contamination. A preliminary study was conducted to determine if ascarid ova of different species could be identified by size and appearance utilizing light microscopy alone; results did not support the differentiation of species via these methods. To determine the prevalence of environmental contamination with ascarid ova, samples of approximately 250 g of soil were collected from park green areas, playgrounds, public housing areas, parkways, and a school. Ova were detected in 46 (14.4%) of 319 samples collected. Ova were collected from three of the 60 (5.0%) park green area samples, 11 of the 40 (27.5%) playground samples, six of the 98 (6.1%) public housing samples, and 26 of the 96 (27.1%) parkway samples. Public areas of Wallingford, Connecticut are frequently contaminated by potentially infectious ascarid ova. Of particular concern is the high degree of contamination of playgrounds and the potential risk these areas pose to children's health.