V. Evaluation of Cross-Immunity against Type 1 Dengue Fever in Human Subjects Convalescent from Subclinical Natural Japanese Encephalitis Virus Infection and Vaccinated with 17D Strain Yellow Fever Vaccine
1 Division of Parasitic Diseases, National Center for Infectious Diseases, and International Health Program Office, Centers for Disease Control and Prevention, Atlanta, Georgia; Ministry of Health and University of Malawi School of Medicine, Blantyre, Malawi
While there is broad evidence for the adverse effects of Plasmodium falciparum infection in pregnancy, and the World Health Organization recommends preventive strategies, there is markedly reduced efficacy in sub-Saharan Africa of the most widely available, affordable and used antimalarial drug for chemoprophylaxis --chloroquine (CQ). During 1987–1990, we studied pregnant women in an area of high malaria endemicity in rural Malawi to compare the efficacy of CQ (the drug recommended by national policy) with mefloquine (MQ, a relatively new and highly effective antimalarial) in preventing low birth weight (LBW) due to prematurity and intrauterine growth retardation (IUGR). Among 1,766 women monitored during at least their last six weeks of pregnancy with observed ingestion of their regimen and facility delivery of a live born singleton, their babies had a mean ± SD birth weight of 2,905 ± 461 gm and 16.8% had LBW. In a multivariate analysis, factors significantly associated with LBW included: first birth (odds ratio [OR] = 4.27), female infant (OR = 2.92), maternal human immunodeficiency virus infection (OR = 2.66), low maternal weight (OR = 1.95), and placental blood P. falciparum infection (OR = 1.71). Factors significantly associated with IUGR-LBW included first birth, female infant, low maternal weight, and placental malaria. Factors significantly associated with preterm-LBW included maternal syphilis infection, umbilical cord blood malaria, first birth, low maternal weight, and female infant. Use of an effective antimalarial (MQ) was protective against LBW through its effect on reducing placental and umbilical cord blood malaria infection. The proportion of LBW babies born to women on MQ (12.5% [parity-adjusted for the population of delivering women]) was significantly lower than the proportion born to women on CQ (15.5%; P = 0.05). Effective prevention of malaria in pregnant women in malaria-endemic settings may reduce the likelihood of LBW by 5–14%, and may reduce the amount of preventable LBW by more than 30%. When evaluating antenatal care programs, health policy makers must consider providing an effective preventive drug (either MQ or other drugs identified in additional studies, e.g., sulfa-pyrimethamine compounds) as a means to prevent low birth weight and its consequences.
Authors’ addresses: Richard W. Steketee, Epidemiology Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, STD, and TB Prevention, Centers for Disease Control and Prevention, Mailstop E-45, 1600 Clifton Road, Atlanta, GA 30333. Jack J. Wirima, University of Malawi School of Medicine and Ministry of Health, Blantyre, Malawi. Allen W Hightower, Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333. Laurence Slutsker, Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention, Mail-stop A-38, Atlanta, GA 30333. David L. Heymann, Emerging and Other Communicable Diseases Programme, World Health Orgnaization, 1211 Geneva 27, Switzerland. Joel G. Breman, Division of International Training and Research, Fogarty International Center, National Institute of Health, Building 31, Room B2C 39, Bethesda, MD 20892-2220.