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.
Shigellosis is an infection of the colon (large intestine) caused by Shigella bacteria. Shigellosis is also called bacillary dysentery because it can cause severe diarrhea. However, the infection often causes only mild symptoms. Shigella can be found in water polluted with infected sewage.