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Wuchereria bancrofti in Tanzania: microfilarial periodicity and effect of blood sampling time on microfilarial intensities
Author(s) -
Simonsen Paul,
Niemann Lea,
Meyrowitsch Dan
Publication year - 1997
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1046/j.1365-3156.1997.d01-237.x
Subject(s) - wuchereria bancrofti , sampling (signal processing) , tanzania , biology , statistics , filariasis , veterinary medicine , blood sampling , nocturnal , mathematics , zoology , helminths , ecology , medicine , geography , physics , optics , environmental planning , detector
The circadian periodicity of Wuchereria bancrofti microfilarial (mf) intensities in peripheral blood was analysed in a group of infected individuals from an endemic community in north‐eastern Tanzania. The mf density was quantified at two‐hourly intervals for 24 hours. A clear nocturnal periodic pattern was observed. Mathematical analysis of the data indicated a peak at 0152 h and a periodicity index of 117.5. A periodicity equation was developed describing the average relation between mf intensity and hour of the day for the study area. Based on the observed periodicity pattern, the effect of blood sampling before peak time is discussed, and the importance of taking sampling time into consideration when analysing data from epidemiological studies is emphasized. A simple method is devised which can be used to adjust for the influence of time on mf intensities, in studies where accurate information on mf intensities is necessary, and where it is impossible to obtain all samples at peak time.