Study Explores Role of Nutrition on Risk of Dengue Virus Infection

Newswise — A new study led by St. Jude Children's Research Hospital investigators disproves reports that well-fed children are more vulnerable to the dengue virus. Mosquitoes spread the virus, which can cause severe flu-like symptoms and sometimes lethal complications.

Malnourished children are just as likely as their well-fed counterparts to develop life-threatening complications following repeated infections with the dengue virus, according to work from researchers at St. Jude and Hospital Nacional de Niños Benjamin Bloom in El Salvador.

Although infectious diseases often pose the greatest threat to children with an inadequate diet, study lead author Gabriela Maron, M.D., a St. Jude Infectious Diseases clinical fellow, said earlier reports from health providers in regions of the world where dengue is common suggested that the infection hit well-nourished children the hardest. Researchers have noted that one possible explanation is that even mild malnutrition blocks the immune system from launching the strong inflammatory response linked to severe dengue infection.

“There must be subtle differences between patients, possibly related to their immune response,” Maron said. St. Jude investigators are now collaborating with colleagues in El Salvador to see if differences in gene expression might identify those at high risk for severe infection.

The study was published in a recent issue of the American Journal of Tropical Medicine and Hygiene.

Health officials estimate about one-third of the world’s population is at risk for infection with one of the four dengue viruses, including a high percentage of children living in the Caribbean, Central and South America. “Even in the U.S., cases are reported along the southern border with Mexico,” Maron said. “Without a vaccine to prevent infection, international flights and the overall shrinking of the planet mean it could become an even more important problem for U.S. health officials.”

An individual’s first dengue infection typically produces mild symptoms. But later infections can lead to life-threatening dengue hemorrhagic fever and dengue shock syndrome, which are associated with internal bleeding and a dangerous reduction in the platelets that help blood clot. The challenge for health providers, especially those in countries where resources are scarce, is to rapidly identify patients at higher risk for complications.

In this study, researchers compared the height, weight and body-mass index (BMI) of three groups of children, ages 5 through 12. The groups were youngsters hospitalized for dengue fever and dengue hemorrhagic fever who were compared with healthy classmates living in the same neighborhoods. BMI is a measurement of body mass based on a person’s weight and height.

Those results were compared with an international sample of children of the same age compiled in the World Health Organization’s standardized database. Roughly the same proportion of children in each of the study’s groups qualified as either underweight, overweight or stunted, a possible sign of chronic malnutrition. There was also no difference in the average BMI of study participants, whether healthy or ill.

The study included 74 healthy children, 66 with dengue hemorrhagic fever and 62 with dengue fever. All were treated in El Salvador’s only children’s referral hospital, which is in the capital city San Salvador.

St. Jude Children’s Research HospitalSt. Jude Children’s Research Hospital is internationally recognized for its pioneering research and treatment of children with cancer and other catastrophic diseases. Ranked the No. 1 pediatric cancer hospital by Parents magazine, St. Jude is the first and only National Cancer Institute-designated Comprehensive Cancer Center devoted solely to children, and has treated children from all 50 states and from around the world. St. Jude has developed research protocols that helped push overall survival rates for childhood cancer from less than 20 percent when the hospital opened to almost 80 percent today. St. Jude is the national coordinating center for the Pediatric Brain Tumor Consortium and the Childhood Cancer Survivor Study. In addition to pediatric cancer research, St. Jude is also a leader in sickle cell disease research and is a globally prominent research center for influenza.

Founded in 1962 by the late entertainer Danny Thomas, St. Jude freely shares its discoveries with scientific and medical communities around the world, publishing more research articles than any other pediatric cancer research center in the United States. St. Jude treats more than 5,400 patients each year and is the only pediatric cancer research center where families never pay for treatment not covered by insurance. St. Jude is financially supported by thousands of individual donors, organizations and corporations without which the hospital’s work would not be possible. For more information, go to www.stjude.org.

Expert Available: Gabriela Maron, M.D., is a clinical fellow in the St. Jude Children's Research Hospital Department of Infectious Diseases. The goal of the Infectious Diseases department is to study devastating diseases of childhood through a comprehensive approach including basic science research, translational trial and bedside care.