| Determinants of Infectivity of Pathogens in Vector Ticks |
15 NOV 90 |
80 pages |
| Authors:
Andrew Spielman; HARVARD UNIV CAMBRIDGE MA
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 | This report describes progress on research in which the main goal is to define the physiological properties of ticks that determine the infectivity of pathogens that they transmit. We determined whether female deer ticks Ixodes dammini (Acari: Ixodidae) can be inseminated repeatedly and whether sperm from either mating take precedence in fertilizing eggs. By infesting deer with irradiated male I. dammini, the abundance of these vector ticks may effectively be ... |
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| Determinants of Infectivity of Pathogens in Vector Ticks |
15 NOV 90 |
|
| Authors:
Andrew Spielman; HARVARD UNIV CAMBRIDGE MA
|
 | This final report describes the progress in research in which the main goal was to define the physiological properties of ticks that determine the infectivity of pathogens that they transmit. In order to investigate the potential for Borrelia burgdorferi infection before the recognition of Lyme disease as a clinical entity, the polymerase chain reaction (PCR) was used to examine museum specimens of Ixodes dammini for the presence of spirochete- specific ... |
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| Determinants of Infectivity of Pathogens in Vector Ticks |
01 JUN 88 |
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| Authors:
Andrew Spielman; HARVARD UNIV CAMBRIDGE MA
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| The general objective of this study was to identify environmental stimuli that stimulate infectivity in pathogen-infected Ixodes dammini ticks. We note that elevated ambient temperatures, as would be encountered when infected vectors feed on homeothermic vertebrate hosts, stimulate maturation of certain pathogen in ticks, and we seek to analyze this relationship. An array of heat- induced proteins are synthesized in non attached ticks when ambient temperature reaches near-lethal levels. Of ... |
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| Increased Dissemination of Dengue 2 Virus in Aedes aegypti Associated with Concurrent Ingestion of Microfilariae of Brugia malayi |
87 |
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| Authors:
Michael J. Turell; Thomas N. Mather; Andrew Spielman; Charles L. Bailey; ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FORT DETRICK MD
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| We investigated whether concurrent ingestion of dengue 2 virus and microfilariae of Brugia malayi would increase viral infection and dissemination rates in Aedes aegypti. Infection rates were similar in mosquitoes that ingested virus along or both virus and microfilariae concurrently. However, viral dissemination rates, as determined by recovery of dengue virus from both legs and bodies separately, were significantly greater in mosquitoes that ingested both agents concurrently than in those ... |
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| Function of Mosquito Saliva in Delivery of Pathogens |
APR 86 |
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| Authors:
Andrew Spielman; HARVARD SCHOOL OF PUBLIC HEALTH BOSTON MA DEPT OF TROPICAL PUBLIC HEALTH
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| Aedes aegypti mosquitoes salivate during intradermal probing of vertebrate prey before ingesting blood. Non-salivating mosquitoes locate blood more slowly, and this difference was ascribed to an anti-platelet activity found in the mosquito's saliva. Mosquitoes infected with Plasmodium gallinaceum suffer pathology that specifically impairs salivary anti-hemostatic activity but without reducing volume of output. Stochastic functions for the probability of feeding success and desistance were derived using data from observations on 300 ... |
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| Function of Mosquito Saliva in Delivery of Pathogens |
FEB 86 |
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| Authors:
Andrew Spielman; HARVARD SCHOOL OF PUBLIC HEALTH BOSTON MA DEPT OF TROPICAL PUBLIC HEALTH
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| This report describes progress on research in which the main goal is to determine how the competence of arthropods to transmit pathogens may be affected by factors that affect their salivation. Ultimately, we hope to derive information that will help to estimate the health hazard associated with different vectors of human disease, to understand how environmental variables may affect such risk and to devise novel health strategies employing vaccines. We ... |
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| Function of Mosquito Saliva in Delivery of Pathogens |
FEB 86 |
|
| Authors:
Andrew Spielman; HARVARD SCHOOL OF PUBLIC HEALTH BOSTON MA DEPT OF TROPICAL PUBLIC HEALTH
|
| This report describes progress on research in which the main goal is to determine how the competence of arthropods to transmit pathogens may be affected by factors that affect their salivation. Ultimately, we hope to derive information that will help to estimate the health hazard associated with different vectors of human disease, to understand how environment variables may affect such risk and to devise novel health strategies employing vaccines. A ... |
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| Regulation of Salivary Output by Mosquitoes |
MAY 85 |
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| Authors:
Andrew Spielman; Philippe A. Rossignol; HARVARD SCHOOL OF PUBLIC HEALTH BOSTON MA DEPT OF TROPICAL PUBLIC HEALTH
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| A major scientific advance was registered during the present reporting period when discovered that the saliva of mosquitoes mainly functions during blood-feeding by preventing platelets from aggregating. Salivary-ablated mosquitoes probe extensively, but without feeding. The salivary enzyme mainly responsible for this antihemostatic effect was identified as an apyrase, which may partially be conserved during sugar-feeding, but selectively released when hosts are probed. Resynthesis, however, is rapid. Chemosensory factors regulate salivary ... |
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