Volume 8, Number 5—May 2002
Research
Genetic Variants of Ehrlichia phagocytophila1, Rhode Island and Connecticut
Table 1
Spatial and temporal variation in the occurrence and distribution of Ehrlichia phagocytophila-human agent (EP-ha) and E. phagocytophila variants, Connecticut and Rhode Island, 1996–1999
| Collection site | Year | No. | Adult | Nymph | No. of PCR-positive ticks (%) | No. of PCR products sequenced | Proportion infected with— |
|||
|---|---|---|---|---|---|---|---|---|---|---|
| EP-ha | Variant 1 | Variant 2 | ||||||||
| Bridgeport, CT | 1996 | 30 | + | 7 | (23.3) | 7 | 100% | |||
| 1997 | 60 | + | 7 | (11.7) | 7 | 100% | ||||
| 1998 | 82 | + | 5 | (6.1) | 5 | 100% | ||||
| 1998 | 101 | + | 19 | (18.8) | 19 | 100% | ||||
| 1999 | 102 | + | 12 | (11.8) | 12 | 100%a | 8.3%a | |||
| Bluff Point, CT | 1997 | 79 | + | 9 | (11.4) | 9 | 55.6% | 44.4% | ||
| South Kingstown, RI | 1996 | 31 | + | 5 | (16.1) | 5 | 60% | 40% | ||
| 1997 | 112 | + | 52 | (46.4) | 30 | 10% | 3.3% | 86.7% | ||
| 1997 | 120 | + | 46 | (38.3) | 37 | 13.5% | 13.5% | 73% | ||
| 1998 | 91 | + | 5 | (5.5) | 5 | 20% | 80% | |||
| 1999 | 103 | + | 5 | (4.9) | 5 | 80% | 20% | |||
| 1999 | 81 | + | 10 | (12.3) | 10 | 80% | 20% | |||
aIncludes one tick that was positive for both the human granulocytic ehrlichiosis agent and variant 1.
PCR = polymerase chain reaction.
1Since this study was conducted, new nomenclature (Anaplasma phagocytophila) has been proposed; see Dumler JS, Barbet AF, Bekker CP, Dasch GA, Palmer GH, Ray SC, et al. Reorganization of genera in the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales: unification of some species of Ehrlichia with Anaplasma, Cowdria with Ehrlichia, and Ehrlichia with Neorickettsia, descriptions of six new species combinations and designation of Ehrlichia equi and ‘HGE agent’ as subjective synonyms of Ehrlichia pagocytophila. Int J Syst Evol Microbiol 2001;51:2145-65.