Eggs of Toxocara spp. in the environment and their public health implications.

The high prevalence of Toxocara in cats, dogs and foxes results in the contamination of soil with infective eggs of Toxocara spp. which are found in soil samples from public and private places worldwide. In Poland the most contaminated areas were city backyards where 38-53% of soil samples were positive, especially in the spring. Human exposure to infection with Toxocara spp. was proportional to the prevalence of eggs in the samples examined but soil texture was not a critical factor in the degree of soil contamination. Eggs of Toxocara spp. placed on the ground penetrated a sand soil profile slowly. Their presence in the superficial layer of soils and the role of earthworms are instrumental in the dissemination of Toxocara eggs.

[Distribution of sources of Toxocara spp. infection in urban and rural environments in Poland]. / Rozmieszczenie zródel inwazji Toxocara spp. w srodowisku miejskim i wiejskim w Polsce.

Soil examinations made in 5 regions of Poland in the 1990s comprised 1184 samples taken from urban areas and 590 samples from suburban and rural areas. Toxocara spp. eggs were found more often in urban areas (14% positive samples) than in suburban and rural once (12% positive samples). The average ratio of positive samples was: in the streets and roads--19.3% (0.36 eggs/100g of soil), near houses (backyards, gardens)--18.6% (1.11 eggs/100g), in sandpits--13.0% (0.23/100g), in parks and public gardens--10.5% (0.46 eggs/100g), on playgrounds and playing fields 9,4% (0,06 eggs/100g) and on the beaches--3.4% (0.03 eggs/100g). In children habitual play areas the prevalence of T. cati eggs was higher than T. canis eggs.

[Soil contamination with Toxocara spp. eggs in the Kraków area and two nearby villages]. / Zanieczyszczenie gleby jajami Toxocara spp. na terenie krakowa i pobliskich wsi.

The distribution of Toxocara spp. eggs was studied in the Kraków city and nearby villages Grodkowice and Lazkowice. In Kraków out of 80 samples surveyed 30% were positive and the mean egg density was 3.7 eggs/100g soil. Court-yards and squares in the centre of the city were the most heavily contaminated areas (58% samples positive). In two nearby villages Toxocara spp. eggs were present in 16% samples examined and the mean egg density was 0.8 eggs/100g soil. Almost 90% of Toxocara spp. eggs recovered were infective. At least 80% of the eggs were classified as T. cati by egg's morfology.

[Biological infection of soil on the flooded areas of Wroclaw City]. / Biologiczne skazenie gleby na terenach popowodziowych we Wroclawiu.

The distribution of geohelminth eggs on the appartment backyards of Wroclaw city after flood disaster was studied. Out of 100 soil samples examined 17% were positive. Toxocara spp.eggs were present in 6% samples examined, Ascaris spp. in 2% and other eggs (Capilaria sp. and Trichuris vulpis) in 9% samples examined. Soil contamination of Wroclaw area was much less than in other cities of Poland and Europe. The prevalence of geohelminth eggs on flooded areas was very similar to that on the not-flooded areas although the number of eggs recovered was twice as high on flooded areas.

[Toxocariasis in dogs and contamination of soil with Toxocara spp. eggs in the Poznan region]. / Toksokaroza u psów i zanieczyszczenie gleby jajami Toxocara spp. w aglomeracji poznanskiej.

Dogs and soil samples from Poznan city and the nearby small town Murowana Goslina were surveyed for the presence Toxocara eggs. On the areas examined, the range of dog's infections with T. canis and the contamination of the soil with the infective stage of Toxocara spp. were not paralleled. In Poznan city out of 617 dogs examined 11.8% were infected with adult form of T. canis and since 1980th the prevalence has decreased. In Murowana Goslina as much as 35.2% dogs out of 352 examined were infected. On the contrary the range of soil contamination with Toxocara spp. eggs was higher in Poznan (12% positive soil samples) than in Murowana Goslina (7% positive soil samples). The most heavily contaminated areas in both localities were urban backyards with 19% (Murowana Goslina) and 27% (Poznan) of soil samples positive; a mean egg density was 1.98 eggs/100 g and 0.48 eggs/100 g respectively. Contrary to the generally accepted opinion, the study suggests, that exposure of human population to Toxocara spp. infections may be higher in urban agglomeration than in the country. T. cati infections may be an important cause of human toxocarosis and the court yards as a play-grounds may be more risky source of Toxocara spp. infection than sand-boxes.

[Evaluation of soil sanitation on Poznan beaches based on helminth examination]. / Ocena stanu sanitarnego gleby plaz poznanskich na podstawie badan helmintologicznych.

It was proved that the soil of recreational areas can be potential source of human geohelminthiosis. The eggs of Ascaris lumbricoides and Trichocephalus trichiurus as well as of Toxocara canis were found on the beaches of Poznan lakes.

[The effect of biotic factors on the eggs of Ascaris spp]. / Wplyw czynników biotycznych na jaja Ascaris spp.

There are many organisms that influence development and survival of eggs of Ascaris sp. Fungi, Acari, Collembola and bacteria are the most important among them. They participate mainly in auto-dehelminthisation processes of environment.