Biopharmaceutical Solutions

Background information

• What is Shigellosis?
  Shigellosis is an infection by bacteria of the genus Shigella that causes severe abdominal symptoms, including diarrhea, dysentery, abdominal cramps, fever, and rectal pain. Shigellosis can result in death. The disease is more dangerous than other gut pathogens because it can penetrate the lining of the intestine and cause severe inflammation of the intestine and systemic complications. 
• Global burden
  Worldwide there are approximately 165 million cases of shigellosis annually, causing over 1.1 million deaths. Nearly 70 percent of all episodes and approximately 60 percent of all deaths attributable to shigellosis involve children under five years old.
  
• Geographic distribution
  S. sonnei is the most common species in the United States and other industrialized countries. S. flexneri is endemic to the developing world. S. boydii is common only in India. S. dysenteriae type 1 is associated with epidemic outbreaks of shigellosis in confined populations such as can occur following natural disaster or political unrest.
  
• Causative agent/transmission
  Shigellosis is caused by bacterial infection by one of four species of Shigella: S. dysenteriae, S. flexneri, S. boydii, and S. sonnei. Transmission occurs via consumption of food and water contaminated by human waste.
  

Presentation

Shigella bacteria multiply within the epithelial cells of the colon, cause cell death, and spread laterally to infect and kill adjacent epithelial cells, resulting in mucosal ulceration, inflammation, and bleeding. Shigella dysenteriae serotype 1 produces severe disease and may be associated with life-threatening complications. Symptoms of shigellosis include diarrhea and/or dysentery with frequent mucoid bloody stools, abdominal cramps, and tenesmus. In some children, shigellosis causes seizure. Adults can experience Reiter’s Syndrome as a result of the disease, leading to eye and joint inflammation and reactive arthritis.

Trends

Diarrheal diseases including shigellosis represent an enormous disease burden across all developing countries. Shigellosis is also a concern for travelers.

Although shigellosis can be treated with antibiotics, the most effective drugs are expensive. Antibiotic misuse has led to the emergence of drugresistant Shigella strains.

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