5.2.2 Yersinia Yersinia is a genus of heterotrophic bacteria with 11 recognized species, some of which cause disease in humans, and both pathogenic and non-pathogenic strains of Yersinia have been found in surface water and unchlorinated drinking-water (Lassen 1972; Caprioli et al. 1978; Cafferkey et al. 1993)..2.2 Yersinia Yersinia is a genus of heterotrophic bacteria with 11 recognized species, some of which cause disease in humans, and both pathogenic and non-pathogenic strains of Yersinia have been found in surface water and unchlorinated drinking-water (Lassen 1972; Caprioli et al. 1978; Cafferkey et al. 1993).
1 When a woman ovulates, the egg is able to be fertilized for 12-24 hours (1 day). 2  When sperm enters the woman's body, it remains alive and able to fertilize an egg for 1-5 days. 3  It takes emergency contraception from 12-24 hours to be effective (1 day).  Emergency contraception remains effective for at least 10 days.
EC pills work by preventing or delaying ovulation and preventing sperm from fertilizing the egg. You can use EC right away or up to five days after sex. The sooner you use it, the better it works. There are a bunch of EC pills currently on the market in the U.S. that are made with the hormone levonorgestrel. If you take EC pills within 24 hours after sex, they reduce your risk of pregnancy by up to 95%. Overall, they are 89% effective, meaning they prevent about 7 of 8 pregnancies that normally would have occurred. There are several side effects that you may experience when using an EC pill.