Lyme Disease Factors
Among other findings emerging about Lyme disease are that:
Although its rash and flu-like early symptoms vanish, there can be a second and third stage of the disease if it goes untreated. These can include heart abnormalities, a form of meningitis, and leg and arm weakness. And there may be still other manifestations that are not yet identified. For example, scientists have documented at least one case of transmission of the Lyme spirochete (bacterium) from an infected pregnant mother to her fetus. The deer tick is considered the main vector. But scientists now know there are other insect carriers. The causative agent, a corkscrew-shaped bacterium called the Borrelia burgdorferi spirochete, has recently been found in the blood of flies and mosquitoes. Whether they also transmit the disease is still not proven. A. americanum serves as a secondary vector of Lyme disease in endemic areas. The removal of A. americanum from the site at which ECM developed in two patients and the isolation and identification of the Lyme disease spirochete from A. americanum collected near the second patient's residence provide direct evidence in support of this hypothesis. Further, both A. americanum and I. dammini are active during periods of peak human infection. Neither tick is host-specific. P. leucopus served as a principal host for immature stages of both species while all stages of A. americanum and I. dammini were found on O. virginianus (8). Both mammals are suspected natural reservoirs of the Lyme disease spirochete. Further investigations are needed to define the precise role of this tick in Lyme disease transmission. Clarification is needed on the apparent low frequency of infection, low spirochete burden, and low survival rate in A. americanum. |
