Lyme disease is the most prevalent vector-borne disease affecting human health in the U.S. This project is designed to develop a basic understanding of the population ecology of the deer tick lxodes dammini and factors that regulate the population in southern New York State where Lyme disease has become epidemic. We intend to provide sound ecological basis for improved efforts to understand and control populations of the tick vector of Lyme disease. We will use novel approaches to determine the absolute density of l. dammini populations at field study sites. These estimates will form a basis for calibrating the accuracy of tick sampling methods. The accuracy of host animal examinations, carbon-dioxide-baited tick traps, and drag cloth sampling methods will be determined in field study sites with varying tick densities. We will explore natural population regulation in l. dammini by comparing an established population that has stabilized its growth rate with one that has only recently become established and is still increasing. We will construct a life table for each l. dammini population and determine the rates of mortality for all active stages. The major factors regulating the abundance of l. dammini at each site will be examined by distinguishing off-host mortality from on-host mortality. Mortality due to environmental factors such as temperature and humidity, as well as predators, parasites, and pathogens will be investigated as sources of off-host mortality. Tick feeding and molting success will be used to investigate on-host mortality and will contribute toward understanding the role of host immunity in regulating l. dammini populations in nature. Thus, we will identify important sources of natural mortality that can be exploited to artificially reduce the density of l. dammini populations and the risk of Lyme disease to humans.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
7R01AI028956-03
Application #
2064753
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Project Start
1992-09-01
Project End
1998-08-31
Budget Start
1994-09-01
Budget End
1998-08-31
Support Year
3
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Yale University
Department
Public Health & Prev Medicine
Type
Schools of Medicine
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Levin, M L; Fish, D (2001) Interference between the agents of Lyme disease and human granulocytic ehrlichiosis in a natural reservoir host. Vector Borne Zoonotic Dis 1:139-48
Levin, M L; Fish, D (2000) Acquisition of coinfection and simultaneous transmission of Borrelia burgdorferi and Ehrlichia phagocytophila by Ixodes scapularis ticks. Infect Immun 68:2183-6
Daniels, T J; Falco, R C; Fish, D (2000) Estimating population size and drag sampling efficiency for the blacklegged tick (Acari: Ixodidae). J Med Entomol 37:357-63
Levin, M L; des Vignes, F; Fish, D (1999) Disparity in the natural cycles of Borrelia burgdorferi and the agent of human granulocytic ehrlichiosis. Emerg Infect Dis 5:204-8
Levin, M L; Fish, D (1998) Density-dependent factors regulating feeding success of Ixodes scapularis larvae (Acari: Ixodidae). J Parasitol 84:36-43
Hodzic, E; Fish, D; Maretzki, C M et al. (1998) Acquisition and transmission of the agent of human granulocytic ehrlichiosis by Ixodes scapularis ticks. J Clin Microbiol 36:3574-8
Des Vignes, F; Fish, D (1997) Transmission of the agent of human granulocytic ehrlichiosis by host-seeking Ixodus scapularis (Acari:Ixodidae) in southern New York state. J Med Entomol 34:379-82
Levin, M; Papero, M; Fish, D (1997) Feeding density influences acquisition of Borrelia burgdorferi in larval Ixodes scapularis (Acari: Ixodidae). J Med Entomol 34:569-72
Dister, S W; Fish, D; Bros, S M et al. (1997) Landscape characterization of peridomestic risk for Lyme disease using satellite imagery. Am J Trop Med Hyg 57:687-92
Schwartz, I; Varde, S; Nadelman, R B et al. (1997) Inhibition of efficient polymerase chain reaction amplification of Borrelia burgdorferi DNA in blood-fed ticks. Am J Trop Med Hyg 56:339-42

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