Increase in abundance of immature Ixodes scapularis (Acari: Ixodidae) in an emergent Lyme disease endemic area.
Changes in the abundance of immature Ixodes scapularis Say, the primary vector of Lyme disease, were assessed over a 7-yr period in Westchester County, New York, where the disease is endemic. In total, 4,000 m2 were drag sampled at each of 6 study sites in June and July of 1984 and 1991. The abundance of nymphs collected from all sites was 2.6-fold greater in 1991 than in 1984. Four of the 6 sites had significantly more nymphs in 1991, with increases ranging from 1.1- to 46.5-fold. The abundance of larvae collected from all sites was 34.2-fold higher in 1991 than in 1984. Five of the sites sampled had significantly more larvae in 1991, with increases ranging from 2.7- to 681-fold. These data demonstrate that populations of immature I. scapularis in Westchester County have, overall, increased during the 7-yr period from 1984 to 1991. However, the magnitude of increase is not uniform from site to site.
Falco
R C
RC
Department of Community and Preventive Medicine, New York Medical College, Valhalla 10595, USA.
Daniels
T J
TJ
Fish
D
D
D000818:Animals; D006801:Humans; D007814:Larva; D008193:Lyme Disease / Q000453:epidemiology / Q000469:parasitology*; D009518:New York / Q000453:epidemiology; D009758:Nymph; D011156:Population Density; D013987:Ticks