[HIV infection in Saint Petersburg: the changing face of the epidemic].

The specific features of the epidemiological situation in St. Petersburg at the first stage (1987-1995) and the second stage (1986-1999) of the development of HIV infection are described. During this period morbidity in HIV infection, starting from the insignificant rate of growth, sharply increased.

[Clinico-epidemiological analysis of the cases of HIV infection in the north-western region of Russia].

The paper provides an epidemiological characterization of HIV infection spread in a Russia's large region with more than 10 million people. The epidemiological findings show that the significant onset of HIV infection occurred among the population in this region in mid 1988. Homosexuals and bisexuals are prevalent among the HIV-infected, sexual contact is the main mode of HIV transmission.

[The basic epidemiological traits of Lyme disease in the northwestern USSR].

Dissemination, season variability, ways of infection, as well as main carriers of Lyme's disease and tick-borne encephalitis, reasons for the population contact with natural foci and ticks, age and socially professional status were shown to be extremely similar in patients with borreliosis and encephalitis in Leningrad Province. This fact indicates principal similarity of basic epidemiological properties in two etiologically different infections. A much higher morbidity level is characteristic of Lyme's disease.