When looking at the prevalence of trichuriosis among the inhabitants of Baltic states we see the same picture as with ascariosis: with a high (12.6%) prevalence in Lithuania in 1949, which declined to 9% by 1959. For Estonia, the first data are from 1959 indicating a low prevalence of 0.21%. The results of an independent study by Kondratjeva et al. (1963) give the prevalence of 1.1% in 1961 in Estonia. By the middle of the 1960s, the prevalence in Estonia was below 0.1% and has been falling further since then, with only single cases being registered during the last years. In Latvia, 0.9% prevalence was registered in 1967 and 18 cases registered in 1996 (0.005% prevalence). In Lithuania, the prevalence of trichuriosis reached lower than 1% in 1981, and has remained at 0.14% for the last years with a little more than 750 cases.
As with the significant decrease in the prevalence of ascariosis and trichuriosis in humans, a similar tendency has been observed for the contamination of soil with the eggs of corresponding helminths (Jogiste and Barotov 1993). In the 1960s, about 4% of the soil probes in Estonia were contaminated with the helminth eggs, while in the 1980s only 0.9% was reported. The percentage of vegetables found to be contaminated decreased during the same period from 1.7% to 0.7%.
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