Part II. Analysis of data gaps pertaining to Shigella infections in low and medium human development index countries, 1984-2005

Abstract

The global incidence of Shigella infection has been estimated at 80-165 million episodes annually, with 99% of episodes occurring in the developing world. To identify contemporary gaps in the understanding of the global epidemiology of shigellosis, we conducted a review of the English-language scientific literature from 1984 to 2005, restricting the search to low and medium human development countries. Our review yielded 11 population-based studies of Shigella burden from seven countries. No population-based studies have been conducted in sub-Saharan Africa or in low human development countries. In studies done in all age groups, Shigella incidence varied from 0.6 to 107 episodes/1000 person-years. S. flexneri was the most commonly detected subgroup in the majority of studies. Case-fatality rates ranged from 0% to 2.6% in population-based studies and from 0% to 21% in facility-based studies. This review highlights the large gaps in data on the burden of Shigella infections for low human development index countries and, more specifically, for sub-Saharan Africa.

Fig. 1

Incidence of shigellosis, by geographic region, 1984–2005. Countries contributing incidence data: China [5], Thailand [6], Egypt [7], Bangladesh [8] and Brazil [9].

Fig. 2

Frequency of Shigella isolation in diarrhoeal or dysenteric stools for all age groups, by geographical area, in studies from medium and low human development index (HDI) countries (n=70 studies).

Fig. 3

Frequency of Shigella isolation in diarrhoeal or dysenteric stools by age group, among children aged <15 years, in studies from medium and low human development index (HDI) countries, 1984–2005 (n=70 studies).

Fig. 4

Frequency of Shigella subgroups detected among Shigella isolates from medium and low human development index (HDI) countries, 1984–2005 (n=56 studies).

Fig. 5

Frequency of S. dysenteriae among Shigella isolates, by per capita gross domestic product (GDP) (adjusted for purchasing power parity, PPP) of medium and low human development index (HDI) countries, 1984–2005 (n=56 studies) (R=−0·54, P<0·0001). The names of study countries and the years of study are indicated for selected studies.

Fig. 6

Frequency of S. sonnei among Shigella isolates, by per capita gross domestic product (GDP) (adjusted for purchasing power parity, PPP) of medium and low human development index (HDI) countries, 1984–2005 (n=56 studies) (R=0·55, P<0·0001). The names of study countries and the years of study are indicated for selected studies.