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.
Shigella. Shigella bacteria can contaminate any food that has been washed in contaminated water. Symptoms typically develop within seven days of eating contaminated food and last for up to a week. An infection caused by Shigella bacteria is known as bacillary dysentery or shigellosis.he bacteria are usually found on raw or undercooked meat (particularly poultry), unpasteurised milk and untreated water. The incubation period (the time between eating contaminated food and the start of symptoms) for food poisoning caused by campylobacter is usually between two and five days.