exists and is an alternate of . The sperm that reach the egg swim into it and attempt to penetrate the zona pelluca, which is the semi permeable outer membrane of the egg. Some sperm have a shape which makes this relatively easy, and others which are poorly formed are likely to have more difficulty.
1 Shigellosis is an infectious disease caused by a group of bacteria called Shigella. 2  Symptoms of Shigella infection include diarrhea (often bloody), fever, and stomach cramps starting a day or two after exposure to the bacteria. 3  Shigellosis usually resolves in 5 to 7 days.
Most people who are infected with Shigella develop diarrhea, fever, and stomach cramps after being exposed to the bacteria. [11, 16, 26] Symptoms may start 12 to 96 hours after exposure, usually within 1 to 3 days. [1, 16] Diarrhea may range from mild to severe, and it usually contains mucus.