[Contamination of protozoa by enteroviruses in fresh water and sewages].

AIM: To determine rate of infection of protozoa by enteroviruses to assess the potential role of protozoa as a natural reservoir of enteroviruses. MATERIALS AND METHODS: The samples were collected from flowing and stagnant water reservoirs in Orenburg region in summer and autumn. The samples of sewages were taken in all stages of their treatment. Cultures of protozoa were isolated with micromanipulator equipped with micropipette, incubated on Pratt's medium at 25 degrees C and fed with Pseudomonas fluorescens culture. RNA of enteroviruses was detected by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Seventy-two protozoan species were found in Ural river, whereas 15 and 38 species were found in lakes and sewages respectively. Enteroviruses were detected by RT-PCR in 61.8% cultures of protozoa belonging to 23 species of flagellates, amoebae and ciliates isolated from natural water bodies undergoing anthropogenic impact as well as from sewages in all stages of their treatment. Predominant localization of enteroviruses in dominant taxons of protozoa (Paraphysomonas sp., Spumella sp., Petalomonas poosilla, Amoeba sp.) was noted. CONCLUSION: Obtained data confirm presence of enteroviruses in protozoa living both in flowing and stagnant recreation natural water bodies as well as in sewages and confirm the hypothesis of persistence of enteroviruses in protozoa and the reservoir role of the latter. Contingency of life cycles of viruses and protozoa allows to explain the seasonality of aseptic meningitis incidence caused by enteroviruses, which peaks in summer and autumn when protozoa massively multiply in water bodies.

Immune and interferon status in schoolchildren living in cities with different anthropogenic load.

Examinations of 6-11-year healthy children living in industrial cities of the Orenburg region revealed a close relationship between ecological status of the territory and some immunity parameters such as immune deficiency, interferon content, and formation of postvaccinal immunity with live measles vaccine. The most pronounced changes in the immune status and decreased postvaccinal immunity were found in a city with the greatest anthropogenic load. Changes in interferon status were similar in all cities: a 2-fold increase of serum interferon and suppressed production of interferon-alpha and interferon-gamma.