Diversity and Distribution of Rice Blast (Pyricularia oryzae Cavara) Races in Vietnam.

A total of 239 isolates of blast (Pyricularia oryzae Cavara) collected from northern and central Vietnam showed a wide variation in pathogenicity based on the reaction patterns to 25 differential varieties (DVs) harboring 23 resistance genes and susceptible cultivar Lijiangxintuanheigu (LTH). The frequencies of isolates virulent toward DVs for Pish, Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Pi9(t), Piz-5, Pita-2, and Pita were low, but they were high for DVs for Pib, Pit, Pia, Pii, Pi3, Pi5(t), Pik-s, Piz, Piz-t, Pi12(t), Pi19(t), and Pi20(t). Isolates were classified into three cluster groups Ia, Ib, and II based on reaction patterns to DVs and LTH. The frequencies of isolates virulent toward 11 DVs for Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Pi9(t), Piz, Piz-5, Pita-2, and Pita in cluster II and DV for Piz-t were higher and lower than those of Ia and Ib, respectively. The frequencies to DVs for Pii, Pi3, Pi5(t), and Piz-t were different between clusters Ia and Ib. Clusters Ia and Ib were distributed with similar frequencies in the northeast, north central, and south central coast regions, but the frequencies among three cluster groups in the Red River Delta and northwest regions were different. This means that the blast races in these two regions were different from the others. Overall, the blast isolates were categorized into 153 races. Among them, 26 were selected as a set of standard differential blast isolates for characterizing 23 resistance genes and developing a differential system in Vietnam.

Sexually transmitted infections among pregnant women attending an antenatal clinic in Fuzhou, China.

OBJECTIVE: To determine the prevalence of sexually transmitted infections (STIs) among women attending an antenatal clinic in urban China and to show whether reported symptoms and findings on clinical examination predicted STIs in this population. STUDY DESIGN: Cross-sectional descriptive study was conducted among 504 pregnant women attending an antenatal clinic in Fuzhou, China. Structured questionnaires were used to collect demographic and behavioral information, and clinical and gynecologic examinations were performed to detect clinical signs of STIs. Blood samples, vaginal swabs, and cervical swabs were collected, respectively, to test for antibodies to syphilis, culture Trichomonas vaginalis (T. vaginalis), and perform PCR to detect Chlamydia trachomatis (C. trachomatis) and Neisseria gonorrhoeae (N. gonorrhoeae). RESULTS: C trachomatis was detected in 51 (10.1%), N gonorrhoeae in 4 (0.8%), T vaginalis in 16 (3.2%), and syphilis in 1 (0.2%) of the 504 pregnant women. Fifty-two (73%) of 71 women with any STI were asymptomatic. Multiple logistic regression analysis indicated that age RMB 2000 yuan (OR=3.57) were significant independent risk factors for chlamydial infection (P<0.05). The reported symptom of vaginal discharge or the clinical sign of either vaginal or cervical discharge poorly predicted infection with C trachomatis, N gonorrhoeae, or T vaginalis, with a positive predictive value <25% for each STI. CONCLUSION: A substantial prevalence of STIs, including a large proportion of asymptomatic infections, was found among pregnant women in the study area. These results support a strategy of screening pregnant women for bacterial STIs (followed by treatment of infections), which could be integrated into routine pregnancy care in China.