© 1994 Oxford University Press
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DNA Probes as Epidemiological Tools for Surveillance of Plasmodium falciparum Malaria in Thailand

*Department of Tropical Public Health, Harvard School of Public Health Boston, MA 02105, USA
**Malaria Center Region 2, Chieng Mai 50000, Thailand
Program in Epidemiology, College of Human Medicine, Michigan State University East Lansing, MI 48824, USA
Barker R H Jr (Department of Tropical Public Health, Harvard School of Public Health, Boston, MA 02105, USA), Banchongaksorn T, Courval J M, Suwonkerd W, Rimwungtragoon K, Srittong N and Wirth D F. DNA probes as epidemiological tools for surveillance of Plasmodium falciparum malaria in Thailand. International Journal of Epidemiology 1994; 23: 161168.
We have previously reported on development of a DNA probe-based method for diagnosing Plasmodium falciparum infection directly from patient blood samples. In the present studies, we sought to examine applicability of the method to large epidemiological surveys, comparing sensitivity, specificity, time required to obtain results, and costs with those of conventional microscopic examination. Results of DNA probe hybridization were also compared between laboratories in the US and Thailand, to assess transferability of the DNA probe technology. Five separate surveys of approximately 5000 villagers each were performed between December 1987 and June 1989 (26 176 samples total). Sensitivity ranged from 61% to 92% for both US and Thai laboratories, while specificity ranged from 98.2% to 99.9%. Agreement between the US and Thai laboratories was good, with kappa coefficients between 0.62 and 0.78 for different surveys. Between 4 and 8 person-days were required to obtain results from each set of 5000 samples by DNA hybridization, whereas microscopic examination required 150 person-days. Approximate costs were US$0.17 per sample for DNA probe analysis, and US$0.36 for microscopic examination. We conclude that the DNA probe method offers significant advantages when large numbers of samples must be surveyed for P. falciparum.
Received 1 August 1993