Shigellosis

Shigellosis
Shigellosis, or 'baciliary dysentery', is an intestinal infection that is a major public health problem in many developing countries, where it causes about 5 to I0 per cent of childhood diarrhoea.

Shigellosis is found throughout the world, mostly in children aged under five. Rates of Shigella infection are highest where sanitation is poor. They are also influenced by nutritional status, and environmental factors affecting transmission such as rainfall and temperature. Shigella infections can occur throughout the year, but in most communities the incidence is highest when the weather is hot and dry. This may be because the scarcity of water limits handwashing and other hygiene measures that reduce transfer of the very small number of bacteria needed to cause infection.

Health workers are usually aware of the number of shigellosis cases, because symptoms are severe, and therefore children with Shigella infections are more likely to be brought to hospitals or clinics. Case fatality rates, even in hospitalised cases of dysentery, are six to eight times greater than for watery diarrhoea. Dysentery is associated with persistent diarrhoea. In rural north India, for example, nearly a third of all persistent diarrhoeal episodes are dysenteric.

During disease epidemics caused by Shigella dysenteriae type 1, as many as one in ten people in affected communities will become infected, and as many as 10 to 15 per cent of these will die. At the Diarrhoea Treatment Centre of the International Centre for Diarrhoeal Disease Research in Bangladesh (ICDDR, B), over 700 patients a year with shigellosis are admitted to an in-patient unit. Ten per cent of these patients die while in hospital.
Shigellosis