Signs and symptoms
Signs and symptoms may range from mild abdominal discomfort to full-blown dysentery characterized by cramps, diarrhea, with slimy-consistent stools, fever, blood, pus, or mucus in stools or tenesmus. Onset time is 12 to 96 hours, and recovery takes 5 to 7 days. Infections are associated with mucosal ulceration, rectal bleeding, and drastic dehydration. Reactive arthritis and hemolytic uremic syndrome are possible sequelae that have been reported in the aftermath of shigellosis.The most common neurological symptom includes seizures. Cause
Bacteria
Shigellosis is caused by a bacterial infection with Shigella, a bacterium that is genetically similar to and was once classified as E. coli. There are three serogroups and one serotype of Shigella:

Shigella flexneri
Shigella boydii
Shigella dysenteriae and
Shigella sonnei (serotype)The probability of being infected by any given strain of Shigella varies around the world. For instance, S. sonnei is the most common in the United States, while S. dysenteriae and S. boydii are rare in the U.S. Transmission
Shigella is transmitted through the fecal-oral route of individuals infected with the disease, whether or not they are exhibiting symptoms. Long-term carriers of the bacteria are rare. The bacteria can infect not just humans but other primates as well. Mechanism
Upon ingestion, the bacteria pass through the gastrointestinal tract until they reach the small intestine. There they begin to multiply until they reach the large intestine.
The primary prevention methods are improved sanitation and personal and food hygiene, but a low-cost and efficacious vaccine would complement these methods.Since shigellosis is spread very quickly among children, keeping infected children out of daycare for 24 hours after their symptoms have disappeared, will decrease the occurrence of shigellosis in daycares. Vaccine
Currently, no licensed vaccine targeting Shigella exists. Several vaccine candidates for Shigella are in various stages of development including live attenuated, conjugate, ribosomal, and proteosome vaccines. Shigella has been a longstanding World Health Organization target for vaccine development, and sharp declines in age-specific diarrhea/dysentery attack rates for this pathogen indicate that natural immunity does develop following exposure; thus, vaccination to prevent the disease should be feasible. Shigellosis is resistant to many antibiotics used to treat the disease, so vaccination is an important part of the strategy to reduce morbidity and mortality. Treatment
Treatment consists mainly of replacing fluids and salts lost because of diarrhea. Replacement by mouth is satisfactory for most people, but some may need to receive fluids intravenously. Antidiarrheal drugs (such as diphenoxylate or loperamide) may prolong the infection and should not be used. Antibiotics
Antibiotics should only be used in severe cases or for certain populations with mild symptoms (elderly, immunocompromised, food service industry workers, child care workers). For Shigella-associated diarrhea, antibiotics shorten the length of infection, but they are usually avoided in mild cases because many Shigella strains are becoming resistant to common antibiotics.