Focus Area: Infectious Diseases and Antimicrobial Resistance (AMR)
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| Photo: JHU/CCP/Mwanza, L. |
Statement of the Problem
Infectious diseases account for 63% of deaths in children ages 0-4 years. Unfortunately, acute respiratory infection (ARI), diarrheal diseases, tuberculosis, malaria, and other diseases have been shown to develop some degree of resistance to commonly used antimicrobial drugs. As a result, the decreasing effectiveness of these drugs has contributed to persistent infections, higher morbidity and mortality, prolonged hospitalization and increased health expenditures. The emergence of drug resistance and new infectious agents presents a serious challenge to global public health.
A. Burden of Disease Due to Malaria
Approximately 2 billion people, roughly a third of the world’s population, live in malaria-endemic areas. Malaria is a leading cause of morbidity and mortality for many of these people, and imposes a substantial economic and social burden on these societies, particularly in sub-Saharan Africa. Of the four species of Plasmodia that cause human disease, P. falciparum causes the greatest burden of disease and death worldwide.
Though precise data is lacking, most estimates agree that malaria causes at least one million deaths per year. The proportion of childhood deaths caused by malaria appears to have been rising during the last three decades. Factors contributing to the high burden of malaria mortality in Africa include continued reliance on chloroquine (CQ) despite high rates of treatment failure, the widespread presence of highly competent vectors in the Anopheles gambiae complex, and limited access to effective medical care.
B. High Risk Groups
Young children and pregnant women are particularly vulnerable to malaria. An estimated 400 to 900 million episodes of fever occur annually in children in sub-Saharan Africa of which approximately half are likely to be due to malaria. More than 75% of these occur in sub-Saharan Africa in children under the age of 5 years. Indirect effects of the heavy burden of malaria in African children include chronic anemia, impaired growth, and delayed cognitive development. Despite having multiple clinical attacks of malaria annually, only 1-2% of young children develop severe malaria. Children who survive severe malaria are at increased risk of permanent deafness, mental retardation and other serious sequelae of cerebral malaria, and those with anemia severe enough to require transfusion are at high risk of blood born viral infections, including HIV.
P. falciparum infection during pregnancy increases the chances of fetal death, prematurity, intrauterine growth retardation, low birth weight (LBW), and maternal anemia. During pregnancy malaria episodes occur more frequently and are more severe than in the absence of pregnancy. In sub-Saharan Africa, malaria is estimated to contribute to more than 20% of maternal deaths each year as well as 75,000 to 200,000 infant deaths. This situation has been exacerbated by the HIV epidemic since HIV-seropositive women have a greater risk of complications from malaria during the course of pregnancy.
C. Seasonality
Because P. falciparum malaria is so widespread true epidemics have been difficult to identify. Malaria risk may be perennial (holo-endemic) or display a profound seasonality due to changes in rainfall and hence mosquito densities (meso-endemic). In the highlands of East and Central Africa, and the Horn of Africa, malaria transmission is more variable, with low transmission punctuated by periods of extremely high, epidemic transmission during warm wet periods. However, recent careful epidemiological appraisals of malaria from high-altitude areas of western Kenya have shown that malaria in this region is better described as seasonal or meso-endemic.
D. Major Public Health Consequences/Implications of Prevention
The social and economic burden attributable to malaria is not known precisely, but is believed to be huge. Malaria is responsible for up to 45 million disability-adjusted life years annually across Africa. In economic terms, malaria may cost between 0.25 to 1.3% of a country’s per-person GNP growth rate. Indirect costs to society of malaria include poor educational performance of children, exacerbation of malnutrition, and anemia, which negatively impact both children and adults. Accordingly, effective interventions for the prevention, improved diagnosis and treatment of malaria are likely to produce significant benefits for afflicted populations by alleviating suffering, decreasing mortality, and reducing the socioeconomic burden of disease caused by this widespread parasitic infection.
HaRP Approach
The Health Research Program (HaRP) of USAID seeks to accomplish its goals by conducting research in and building capacity to:
- Combat antimicrobial resistance (AMR) by addressing its major causes and consequences, establishing a global strategy and action plan, contributing to the understanding of mechanisms of AMR, developing methods to detect resistance, responding to data on AMR and drug-use, and preventing and slowing the spread of AMR;
- Conduct research to develop delivery strategies and identify impediments to the successful completion of the global strategy to eradicate polio.
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