Resistance of winter wheat varieties to tan spot in the North Caucasus region of Russia.

Tan spot caused by Pyrenophora tritici-repentis (Died.) Drechsler, in recent years, occupies an increasingly large area on the territory of Russia. Due to the wide distribution and economic significance of this disease, the search for resistant plants to the pathogen is relevant. This paper presents the results of a field assessment for 2017-2019 of 34 regionally distributed winter wheat varieties of Russian selection for resistance to P. tritici-repentis in the North Caucasus region of Russia. Field resistance - the development of the disease up to 30% against the background of artificial infection for three years was shown by 20.5% of the studied varieties. Wheat varieties were assessed for resistance to isolates of tan spot identified as races 1, 3, and 4 in the greenhouse at the seedling stage. The number of resistant accessions for each race was different and ranged from 12 to 20. The 12 varieties showed resistance to race 1, 14 varieties to race 3, 20 varieties to race 4. This research showed that the resistance to tan spot of studied varieties was race-specific. A functional allele of the susceptibility gene Tsn1 to P. tritici-repentis isolates, producing the toxin Ptr ToxA, was diagnosed by PCR method. Of the analyzed 34 varieties, 13 had a dominant allele of the Tsn1 (Tsn1+), and 21 had a recessive allele in the tsn1tsn1 homozygous state. All Tsn1+ varieties, and most varieties with recessive alleles tsn1tsn1, were susceptible to tan spot in the field. Varieties Dolya, Gurt, Lebed and Sila, which showed field resistance, had the tsn1tsn1 genotype. The expected reaction of varieties with different allelic composition of the Tsn1 gene to inoculation with the isolate of race 1, according to the generally accepted model of "gene-to-gene" interaction, did not coincide with that observed in reality, which confirms the results obtained by other authors. Research results demonstrate the effect of weather conditions on the susceptibility of wheat varieties to tan spot. In years with higher humidity and higher average air temperatures, the susceptibility response to the disease was observed in more varieties than in drier years. The studies show that the main part (79.5%) of winter wheat varieties of Russian selection widely zoned in the North Caucasus region of Russia are susceptible to P. tritici-repentis. Varieties that have been resistant to the pathogen in the adult phase in the field for three years and to the pathogen races in which the recessive allele of the tsn1 gene has been identified may be of interest as sources of resistance for developing new disease-resistant varieties.

Five-year trends in epidemiology and prevention of mother-to-child HIV transmission, St. Petersburg, Russia: results from perinatal HIV surveillance.

BACKGROUND: The HIV epidemic in Russia has increasingly involved reproductive-aged women, which may increase perinatal HIV transmission. METHODS: Standard HIV case-reporting and enhanced perinatal HIV surveillance systems were used for prospective assessment of HIV-infected women giving birth in St. Petersburg, Russia, during 2004-2008. Trends in social, perinatal, and clinical factors influencing mother-to-child HIV transmission stratified by history of injection drug use, and rates of perinatal HIV transmission were assessed using two-sided χ2 or Cochran-Armitage tests. RESULTS: Among HIV-infected women who gave birth, the proportion of women who self-reported ever using injection drugs (IDUs) decreased from 62% in 2004 to 41% in 2008 (P<0.0001). Programmatic improvements led to increased uptake of the following clinical services from 2004 to 2008 (all P<0.01): initiation of antiretroviral prophylaxis at ≤28 weeks gestation (IDUs 44%-54%, non-IDUs 45%-72%), monitoring of immunologic (IDUs 48%-64%, non-IDUs 58%-80%) and virologic status (IDUs 8%-58%, non-IDUs 10%-75%), dual/triple antiretroviral prophylaxis (IDUs 9%-44%, non-IDUs 14%-59%). After initial increase from 5.3% (95% confidence interval [CI] 3.5%-7.8%) in 2004 to 8.5% (CI 6.1%-11.7%) in 2005 (P<0.05), perinatal HIV transmission decreased to 5.3% (CI 3.4%-8.3%) in 2006, and 3.2% (CI 1.7%-5.8%) in 2007 (P for trend<0.05). However, the proportion of women without prenatal care and without HIV testing before labor and delivery remained unchanged. CONCLUSIONS: Reduced proportion of IDUs and improved clinical services among HIV-infected women giving birth were accompanied by decreased perinatal HIV transmission, which can be further reduced by increasing outreach and HIV testing of women before and during pregnancy.

HIV seroprevalence in street youth, St. Petersburg, Russia.

BACKGROUND: Reliable data on HIV infection among Russian street youth are unavailable. The purpose of this study was to assess HIV seroprevalence among street youth in St Petersburg and to describe social, sexual, and behavioral characteristics associated with HIV infection. METHODS: A cross-sectional assessment conducted during January-May 2006 included city-wide mapping of 41 street youth locations, random selection of 22 sites, rapid HIV testing for all consenting 15-19-year-old male and female street youth at these sites, and an interviewer-administered survey. Adjusted odds ratios (AOR) were calculated using logistic regression, accounting for intracluster homogeneity. RESULTS: Of 313 participants, 117 (37.4%, 95% confidence interval 26.1-50.2%) were HIV infected. Subgroups with the highest seroprevalences included double orphans (64.3%), those with no place to live (68.1%), those previously diagnosed with a sexually transmitted infection (STI; 70.5%), those currently sharing needles (86.4%), and those currently using inhalants (60.5%) or injection drugs (78.6%), including Stadol (82.3%) or heroin (78.1%). Characteristics independently associated with HIV infection included injecting drugs (AOR 23.0), sharing needles (AOR 13.3), being a double or single orphan (AOR 3.3 and 1.8), having no place to live (AOR 2.4), and being diagnosed with a STI (AOR 2.1). Most HIV-infected street youth were sexually active (96.6%), had multiple partners (65.0%), and used condoms inconsistently (80.3%). DISCUSSION: Street youth aged 15-19 years in St Petersburg, Russia, have an extraordinarily high HIV seroprevalence. In street youth who are injection drug users, HIV seroprevalence is the highest ever reported for eastern Europe and is among the highest in the world.