Project: Research project

Project Details


Malaria is a growing public health problem in many developing countries.
This disease, which is caused by protozoan parasites of the genus
Plasmodium and transmitted by anopheline mosquitoes, continues to resist
all conventional forms of control. Current strategies for vector control
and malaria vaccine development are focusing on specific stages in the
Plasmodium life cycle; several stages which occur in the vector are thought
to be especially vulnerable to interruption. In nature, factors regulating
vector infection rates, sporozoite loads (infective-stage sporozoites in
the salivary glands) and sporozoite transmission are largely unknown.
Comprehensive approaches are needed for evaluating Anopheles vector
potential. The proposed studies will investigate the biology of Plasmodium
development in Anopheles vectors to determine factors affecting sporozoite
transmission potential.

Anopheles gambiae, a highly competent African malaria vector, will be
infected with in vitro cultured gametocytes of P. falciparum, the most
pathogenic human malaria. Variability of infection and sporozoite
transmission will be evaluated by 1) quantifying sequential sporogonic
stages in the vector (ingested gametocytes, ookinetes, oocysts and
sporozoites) 2) quantifying sporozoite dissemination (e.g. in the hemocoel,
salivary glands, salivary duct, etc.), and 3) determining the number of
sporozoites transmitted during feeding, using in vitro methods standardized
against an in vivo mouse model. This will establish a foundation for
investigating the effects of life history and behavior patterns of An.
gambiae (e.g. adult feeding history, adult body size, feeding behavior,
gonotrophic cycles, exposure to multiple infectious hosts, etc.) on
susceptibility to P. falciparum infections, sporogonic development and
transmission potential. Plasmodium falciparum infections will be studied
further in An. arabiensis, An. dirus, An. freeborni and An. stephensi, all
competent vectors, to identify and compare critical points affecting vector
potential. By focusing on regulatory mechanisms for vector potential, this
project will yield new information for studying natural malaria
transmission, for evaluating malaria control programs, and for developing
and field testing malaria vaccines.
Effective start/end date1/1/9012/31/90


  • National Institute of Allergy and Infectious Diseases


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