Characterization of malaria transmission by Anopheles (Diptera

Culicidae) in western Kenya in preparation for malaria vaccine trials.

John C Beier, P. V. Perkins, F. K. Onyango, T. P. Gargan, C. N. Oster, R. E. Whitmire, D. K. Koech, C. R. Roberts

Research output: Contribution to journalArticle

102 Citations (Scopus)

Abstract

Malaria transmission was studied for 33 mo in the villages of Kisian and Saradidi in western Kenya in preparation for field trials of malaria vaccines. Abundance estimates of Anopheles gambiae Giles sensu lato and Anopheles funestus Giles, which constituted over 99% of 26,645 anophelines collected, were compared for all-night biting collections inside houses, outdoors, and in tents. The overall numbers of Anopheles per man-night were 2.3 times greater in Kisian than in Saradidi. For the three types of collections, mean sporozoite rates by dissection ranged from 2.2 to 5.4% for 13,072 Anopheles in Kisian and from 9.9 to 13.6% for 7,058 Anopheles in Saradidi; greater than 90% of the infections were Plasmodium falciparum, either alone or mixed with P. malariae or P. ovale. Heaviest transmission from April to July coincided with the end of the long rainy season. Entomological inoculation rates (EIR) averaged 0.82 infective bites per man per night inside houses in Kisian and 0.65 in Saradidi. Outdoors, EIRs averaged 0.09 in Kisian and 0.52 in Saradidi. In tents, which were evaluated to identify methods for exposing nonindigenous volunteers during vaccine efficacy trials, EIRs were 3.3 and 2.5 times less than inside houses for Kisian (EIR = 0.25) and Saradidi (EIR = 0.26), respectively. Exposure in tents averaged one infective bite every 4.0 d in Kisian and every 3.8 d in Saradidi. The use of tents in vaccine efficacy trials should provide adequate exposure for nonindigenous volunteers. Malaria vaccine trials could be conducted efficiently in western Kenya, with timing dependent upon the intensity of transmission required by vaccine trial objectives.

Original languageEnglish
Pages (from-to)570-577
Number of pages8
JournalJournal of Medical Entomology
Volume27
Issue number4
StatePublished - Jul 1 1990
Externally publishedYes

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Malaria Vaccines
Anopheles
Kenya
Culicidae
Diptera
malaria
Malaria
vaccination
vaccines
volunteers
Vaccines
Bites and Stings
Plasmodium malariae
Anopheles funestus
Volunteers
sporozoites
Anopheles gambiae
Plasmodium falciparum
type collections
Sporozoites

ASJC Scopus subject areas

  • Insect Science

Cite this

Beier, J. C., Perkins, P. V., Onyango, F. K., Gargan, T. P., Oster, C. N., Whitmire, R. E., ... Roberts, C. R. (1990). Characterization of malaria transmission by Anopheles (Diptera: Culicidae) in western Kenya in preparation for malaria vaccine trials. Journal of Medical Entomology, 27(4), 570-577.

Characterization of malaria transmission by Anopheles (Diptera : Culicidae) in western Kenya in preparation for malaria vaccine trials. / Beier, John C; Perkins, P. V.; Onyango, F. K.; Gargan, T. P.; Oster, C. N.; Whitmire, R. E.; Koech, D. K.; Roberts, C. R.

In: Journal of Medical Entomology, Vol. 27, No. 4, 01.07.1990, p. 570-577.

Research output: Contribution to journalArticle

Beier, JC, Perkins, PV, Onyango, FK, Gargan, TP, Oster, CN, Whitmire, RE, Koech, DK & Roberts, CR 1990, 'Characterization of malaria transmission by Anopheles (Diptera: Culicidae) in western Kenya in preparation for malaria vaccine trials.', Journal of Medical Entomology, vol. 27, no. 4, pp. 570-577.
Beier, John C ; Perkins, P. V. ; Onyango, F. K. ; Gargan, T. P. ; Oster, C. N. ; Whitmire, R. E. ; Koech, D. K. ; Roberts, C. R. / Characterization of malaria transmission by Anopheles (Diptera : Culicidae) in western Kenya in preparation for malaria vaccine trials. In: Journal of Medical Entomology. 1990 ; Vol. 27, No. 4. pp. 570-577.
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abstract = "Malaria transmission was studied for 33 mo in the villages of Kisian and Saradidi in western Kenya in preparation for field trials of malaria vaccines. Abundance estimates of Anopheles gambiae Giles sensu lato and Anopheles funestus Giles, which constituted over 99{\%} of 26,645 anophelines collected, were compared for all-night biting collections inside houses, outdoors, and in tents. The overall numbers of Anopheles per man-night were 2.3 times greater in Kisian than in Saradidi. For the three types of collections, mean sporozoite rates by dissection ranged from 2.2 to 5.4{\%} for 13,072 Anopheles in Kisian and from 9.9 to 13.6{\%} for 7,058 Anopheles in Saradidi; greater than 90{\%} of the infections were Plasmodium falciparum, either alone or mixed with P. malariae or P. ovale. Heaviest transmission from April to July coincided with the end of the long rainy season. Entomological inoculation rates (EIR) averaged 0.82 infective bites per man per night inside houses in Kisian and 0.65 in Saradidi. Outdoors, EIRs averaged 0.09 in Kisian and 0.52 in Saradidi. In tents, which were evaluated to identify methods for exposing nonindigenous volunteers during vaccine efficacy trials, EIRs were 3.3 and 2.5 times less than inside houses for Kisian (EIR = 0.25) and Saradidi (EIR = 0.26), respectively. Exposure in tents averaged one infective bite every 4.0 d in Kisian and every 3.8 d in Saradidi. The use of tents in vaccine efficacy trials should provide adequate exposure for nonindigenous volunteers. Malaria vaccine trials could be conducted efficiently in western Kenya, with timing dependent upon the intensity of transmission required by vaccine trial objectives.",
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