Childhood diarrhea can be a tricky public health issue. Not only is it an unpleasant subject to discuss, but eradicating it, especially in poorer nations, can often mean expensive infrastructure projects and bigger battles than many strapped governments can take on.

It still kills some 1.5 million children under the age of five every year, according to a World Health Organization report issued last month. And it likely is responsible for more indirect deaths in that age group. "It doesn't often immediately kill a child," explains Peter Winch, a professor at Johns Hopkins Bloomberg School of Public Health. "It often weakens a child and they die of something else—a lot of [these] deaths occur out[side] of hospitals—so out of sight, out of mind."

A 10-day course of zinc tablets, however, promises to not only treat children who have diarrhea, but also to help protect them from future bouts with the condition (the most common side effect of the zinc being nausea). The challenge lies in getting parents and caretakers to give the treatment to their children—and health care providers to embrace it.

A new multiyear study, published online Monday in PLoS Medicine, followed a nationwide public health campaign to increase zinc use for childhood diarrhea in Bangladesh. Through extensive surveying of households that had current cases of a child with diarrhea in urban, rural and township settings, the researchers were able to uncover how effective public health messages had been in creating awareness about—and use of—the treatment.

The authors found that in the first two years of a public health campaign that used television, radio, outdoor ads, and other communication, awareness of the treatment peaked after about 10 months. Those in the urban areas outside of slums had the highest awareness (90 percent). Levels were lower in townships (74 percent), urban slums (66 percent) and rural areas (50 percent).

"We didn't expect to see awareness go up as quickly as it did," says Charles Larson, of the Center for International Child Health at the BC Children's Hospital in Vancouver and lead author of the study.

By about 23 months into the campaign, however, some 25 percent of urban, non-slum caretakers who had children with a current case of diarrhea were using zinc (along with 20 percent of those in towns and urban slums and 10 percent in rural areas). As Larson points out, any marketing company might be happy if 20 percent of the target population used a product, but given the ease and benefit of using zinc tablets, he says he was "somewhat discouraged" by the latter adoption figures.

Zinc, a metallic element that is naturally present in many foods such as red meat and fish—more widely consumed in wealthier nations—is a co-factor in many different bodily enzymes. "We don't completely understand it," Winch says, but researchers do know that it is important for maintaining many enzymes that contribute to immune system support as well as maintaining skin and intestinal walls. Unlike iron, however, there are not many good, reliable tests for zinc levels, and people who are zinc deficient often don't look any different from those who are not, also unlike people who suffer from anemia, who can be pale and fatigued.

Zinc tablets can also satiate the perceived need for a drug-based treatment. Although widely used oral-rehydration therapies help children regain lost fluids, "people don't perceive it as a treatment," Winch says. "It's not a pill, [so] they're still on the lookout for a drug to take." Many caretakers will get antibiotics, which do not treat most types of typical diarrhea, and could contribute to antibiotic resistance, he says.

One challenge for the zinc scale-up programs is that the treatment course usually lasts longer than the illness itself. Many parents or caretakers discontinue the tablets after symptoms disappear, even though most countries recommend treatment for at least eight days. So, in order to best protect children from a relapse or future sickness, the programs must also convince those getting the medicine to see the full treatment through.

An important lesson from the program has been that, at least in some areas, selecting the right distribution partner can be crucial. In Bangladesh Larson and his team eventually switched from a pharmaceutical firm to a bottled water distributor—a group that didn't have a vested interest in higher profit prescription drugs and had experience with over-the-counter distribution. The project has garnered success using private companies for distribution and marketing, finding that most people purchased the 25-cent pill regimen from stores rather than obtain it from free clinics.

Of course, not all childhood diarrhea cases will benefit from zinc. Those children with more difficult illnesses, such as dysentery, need other medical treatment.

1 Comments

1. 1. PLoS Medicine 06:35 AM 11/9/09

   The lead author of the research mentioned in this article on zinc use for the treatment of childhood diarrhea is actually Charles P. Larson rather than Peter Larson.
   
   The link to the freely available online research follows with an editors' summary aimed at the general reader: http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000175. Like everything else published in PLoS Medicine it is freely available for anyone to read, download, distribute and reproduce.

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