Friday, 14 September 2012

SAFE Strategy Helps Reduce Intestinal Parasites

A 2011 investigation shows that after five years of implementation of the SAFE strategy for trachoma con­trol, the prevalence of intestinal parasites in children ages 2–15 years has decreased in 10 woredas (districts) of South Gondor, Ethiopia. The SAFE strategy refers to surgery, antibiotics (Zithromax, donated by Pfizer), facial cleanliness, and envi­ronmental improvement. Distribution of albendazole also may have played a role in the decline. In addition, the frequency of protozoan infections warrants an investiga­tion of water quality.

The bloody urine of this Nigerian boy indicates
that he suffers from schistosomiasis.
Photo: E. Staub/The Carter Center
A total of 2,338 stool specimens were collected from randomly selected children in 99 communities. (All selected children were offered deworming treat­ment regardless of participation.) The specimens were processed and linked to survey data from a total of 2,657 children (88 percent response). The mean age of children providing specimens was 6.8 years (SD 3.6), and 46.8 percent of the specimens were from boys. The zonal-level prevalence of roundworm (Ascaris), hookworm, whip worm (Trichuris), and any of these three infec­tions was 10.6 percent, 9.8 percent, 2.5 percent, and 20.1 percent, respectively.

The prevalence of intestinal schisto­somiasis was 2.0 percent, but the propor­tion of children infected with schistoso­miasis by community ranged from 0–52.4 percent. Intense helminth infections (≥100 eggs per gram) were observed for roundworm only (16.4 percent of infec­tions) and no other helminth infection. The prevalence of infection with any protozoan was 78.1 percent, and 23.0 percent of children had Giardia cysts in their stool.

Figure 1 shows the improvements in household-level sanitation and water access that have occurred in South Gondar zone since 2000 prior to any SAFE interventions. SAFE interventions were piloted in a few areas until 2003, and by 2006 the implementation of SAFE activities was at scale in all woredas within the zone. Cumulatively, 339,913 household latrines have been constructed, increasing household ownership from 1 percent to 44.4 percent.

Prevalence of worm infections has reduced significantly since a previous survey in 1995 (see Figure 2). While the proportion of children infected with hookworm was not significantly lower than in 1995, none of the current infec­tions were intense. Ascaris and trichuris are transmitted through the fecal-oral pathway, which is affected by the pres­ence of hygiene and sanitation, whereas hookworm is transmitted percutaneously through the feet. In rural Ethiopia, chil­dren are often barefoot, making them more susceptible to this type of infection. A total of 945,991 doses of mebendazole or albendazole were distributed within the zone to preschool-age children in 2005–2011, yet the proportion of this target population that reported taking this medicine was 33.0 percent (24.4–41.5 percent).

Improvements in sanitation and perhaps recent albendazole distribution among preschool-age children have played a role in the observed decline in intestinal helminthiasis. In addition to continued promotion of hygiene and household-level sanitation through the SAFE strategy, expansion of the cur­rent deworming program to school-age children should be considered accord­ing to guidelines of the World Health Organization. The frequency of protozoan infections suggests poor water quality or unsanitary water collection and storage practices, calling for further study.

The Carter Center assists the Amhara National Regional State Health Bureau to eliminate blinding trachoma through the implementation of the SAFE strategy (surgery, antibiotics, facial cleanliness, and environmental improve­ment). The aim of the F component is to reduce contamination of fingers, flies, and fomites by keeping faces free of infectious discharge. The promotion of facial hygiene involves face and hand washing to prevent transmission of C. trachomatis, which also prevents transmission of other infections spread by contact with infec­tious material. The E component aims to improve access to water and sanitation and encourages water use for hygiene purposes. The combined effects of the F and E aspects of SAFE should have an indirect benefit on intestinal parasites, respiratory tract infections, and diarrheal diseases.

Article originally appeared in the August 2012 issue of Eye of the Eagle, a biannual newsletter published by The Carter Center.

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