The History of Ixodes scapularis
in the Northeast

Blacklegged ticks were first collected in New England in the early 1920's from Naushon Island, Massachusetts. Only scattered collections of individual I. scapularis were recorded elsewhere in New England for the next 30 years. Throughout the 1930's, researchers continued to collected I. scapularis on Naushon Island, but not from any other locations. On the nearby islands of Nantucket and Martha's Vineyard, a similar tick species, I. muris, was abundant but not found on Naushon Island. The collections of Hertig and Smiley (1937) confirm this distribution of I. scapularis and I. muris. Ixodes scapularis was first reported from Cape Cod, Massachusetts, in the early 1940's.

During the late 1950's, localized infestations of blacklegged ticks were reported elsewhere along coastal New England. Hyland and Mathewson (1961) collected I. scapularis from Prudence Island, Rhode Island, and from nearby locations around Narragansett Bay. Similar to early records on Nantucket and Martha's Vineyard, collections from Block Island contained only I. muris. At that time, white-tailed deer were also absent from Block Island. A decade later an extensive study reported the presence of I. scapularis on the eastern tip of Long Island, New York, in 1971. Collection records during the 1970's indicate that I. scapularis was now present in scattered sites throughout the Northeast. The larger islands along the New England coast were infested. Ixodes scapularis was also established at coastal mainland sites. Wallis et al. (1978) reported an infestation around the mouth of the Connecticut River. Most of eastern Long Island was infested, as was coastal New Jersey. Furthermore, infestations were first recognized in northwestern Wisconsin and from Long Point, Ontario in Canada.

Spielman et al. (1979) revised the taxonomic status of I. scapularis in the northeastern United States when they described I. dammini as a new species. The basis for separation from I. scapularis was based primarily on nine different morphological features, especially in the nymphal stage. Ixodes scapularis had a distribution extending southward to include most of the southeastern United States. However, with the erection of I. dammini, many of the northern I. scapularis identifications were thought to have been mis-identified I. dammini or I. muris. However, many of the early records of I. muris in New England were also considered to be mis-identified I. dammini. Recently (Oliver et al. 1993), I. dammini has been relegated to a junior subjective synonym of I. scapularis. This decision was based principally on breeding and morphometric experiments between northern populations of I. dammini and southern populations of I. scapularis.

Throughout the 1980's, the recognition and increasing incidence of Lyme disease fueled research of I. scapularis and its distribution now includes much of th eNortheast. Ixodes scapularis was discovered in a nature preserve in Ipswich, Massachusetts and several other mainland locations in southeastern Massachusetts. Furthermore, between 1985 and 1989 the number of counties in New York with documented I. scapularis increased from 4 to 22. Also, there are well-established infestations of blacklegged ticks throughout much of Connecticut, Maine, New Jersey, New York and Rhode Island, especially in southern and coastal areas.

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The History of Ixodes scapularis in the Northeast

The History of Ixodes scapularis
in the Northeast