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.
Symptoms usually last about five to seven days. Some infected people may not experience any symptoms, but can still shed Shigella in their stools. How soon do symptoms appear? Symptoms can start one to seven days after exposure, but usually begin within one to two days. How is Shigella spread? Shigella is found in the intestinal tracts of infected people. The bacteria are spread by direct or indirect contact with fecal material from an infected person. A person with shigellosis may spread infection to others indirectly