Skip to main content

Currently Skimming:


Pages 118-143

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 118...
... 7Vector Biology, Ecology, and Control WHERE WE WANT TO BE IN THE YEAR 2010 Vector biology will play a major role in the battle against malaria. Improved vector surveillance networks will allow most countries, particularly those in Africa, to mount effective control efforts and to predict outbreaks of disease.
From page 119...
... WHERE WE ARE TODAY Vector biology, broadly defined, is the science devoted to studying insects that transmit pathogens, their contact with humans and their interaction with the disease-causing organism. In the case of malaria, the vector is the anopheline mosquito and the disease-causing organism is the malaria parasite.
From page 120...
... to prevent malaria transmission, however. The continuous need for adequate drug supplies to treat clinically ill residents of endemic areas severely limits progress toward malaria prevention.
From page 121...
... 11 days at 24°C and 23 days at 20°C, a different of 14 days over a range of 10°C. At 25°C, the process is completed in 9 days for P
From page 122...
... and oocysts that develop, sporozoites in the hemolymph and in the salivary glands, and sporozoites transmitted during a blood meal have not been well quantified. Most studies of vector competence count only oocysts on the midgut wall and crudely estimate salivary gland sporozoites.
From page 123...
... to parasite and the probability it will survive long enough for the parasite to full develop. Vector biologists know very little about vector-related factors that affect sporozoite viability in nature.
From page 124...
... identify particular Plasmodium species. This is important since sporozoites of all Plasmodium species that infect humans are morphologically similar, and sporozoites of most animal malarias cannot be distinguished morphologically from those that infect humans.
From page 125...
... Mosquito Taxonomy and Species Complexes In malaria entomology, anopheline species are grouped according to morphological criteria and related taxonomic information. Much of modern-day taxonomy addresses problems associated with species complexes, that is groups of morphologically indistinguishable species that are genetically different and that may differ greatly in vectorial potential.
From page 126...
... World Health Organization (1975)
From page 127...
... The equation used to calculate VC is C = ma2pn/-logep, where C = vectorial capacity, m = density of vectors in relation to humans, a = number of blood meals taken on humans per vector per day, p = daily survival probability of vectors (measured in days) , and n = incubation period in the vector (measured in days)
From page 128...
... intensity, derived from measurements of vector densities and sporozoite rates (analogous to the EIR) , can provide useful information about patterns of endemicity in human populations.
From page 129...
... by vector populations in prospective study sites. Baseline information on both the intensity and seasonality of transmission is necessary for planning vaccine trials.
From page 130...
... Antivector measures are the most effective tools for preventing and controlling malaria transmission. Common measures include indoor and outdoor insecticide spraying; the use of insecticide-impregnated bednets and curtains; the treatment of larval development sites with chemical or microbiological larvicides or with biological control agents such as larvivorous fishes; and environmental measures, such as reducing or managing aquatic larval sites, and designing and locating houses and animal shelters in areas with the least possible exposure to malaria transmission.
From page 131...
... contact between the vector and the insecticide, and the degree or intensity of malaria transmission. In many areas of heavy transmission, reducing transmission by even 99 percent may not produce significant decreases in infections rates.
From page 132...
... Over the last several years, field trials in several endemic areas have evaluated the effectiveness of insecticide-treated bednets and curtains (reviewed by Rozendaal, 1989)
From page 133...
... use in indoor residual spraying, provided that the vector is susceptible. This chlorinated hydrocarbon remains one of the most effective insecticides for malaria control efforts in endemic countries.
From page 134...
... immature and adult-stage mosquitoes. A number of studies are looking at candidate biological control agents.
From page 135...
... be that special programs will need to be developed to fund those scientists willing to devote years to working in relative isolation in the field. RESEARCH AGENDA Over the next 15 to 20 years, malaria research in the area of vector biology should focus concurrently on four areas: field investigations, laboratory-based research in support of field investigations, innovative methods for malaria control, and vector control evaluation in endemic areas.
From page 136...
... Regulation of Anopheline Populations Factors affecting larval survival and mechanisms controlling adult production in aquatic habitats are largely unknown, even for the most important vector species. There is limited information on the foraging habits of larvae (what they eat)
From page 137...
... for measuring the risk of exposure for human populations, and for monitoring epidemiologic parameters in human populations (e.g., malaria antibodies, malaria antigens, and drug use) in country-wide efforts to improve malaria management capabilities.
From page 138...
... mechanisms affecting sporogonic development in susceptible anopheline species are largely unknown. A greater understanding of the differences in sporogonic development and transmission potential among vector species may provide important clues about malaria epidemiology and establish new directions for blocking the transmission cycle in nature.
From page 139...
... RESEARCH FOCUS: Development and field testing of immunological and molecular assay systems, in conjunction with studies of natural malaria transmission and malaria control efforts for determining vector-related parameters. Innovative Methods for Malaria Control Antimosquito Vaccines Unlike vaccines directed against the malaria parasite, an antimosquito vaccine would be effective against all Plasmodium species carried by a common vector.
From page 140...
... Drug Development A potentially promising area for malaria prevention is the use of antimalarial drugs to reduce the intensity of parasite transmission by vectors. There is a continuing need for new drugs that kill or reduce the infectivity of gametocytes in the human bloodstream.
From page 141...
... Beier, J
From page 142...
... in Malaria: Principles and Practice of Malariology, Wernsdorfer, W
From page 143...
... freeborni salivary glands. American Journal of Tropical Medicine and Hygiene 34:687–691.

Key Terms



This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.