Emerging Bacterial Zoonotic and Vector-Borne Diseases

Molecular Characterization of Anaplasma phagocytophilum and Borrelia burgdorferi in Ixodes scapularis Ticks from Pennsylvania

“…Ixodid ticks have been shown to play an essential role in the maintenance of A. phagocytophilum and B. burgdorferi in nature, with I. scapularis being the principal vector of these organisms in the northeastern and upper Midwestern United States (10,23,27). Although I. scapularis is primarily known for its role in transmitting these organisms, the potential for these hard ticks to act as both reservoir and amplifier has been suggested (2,11).…”

“…These data suggest that deer may be a reservoir for AP-Variant 1 and that ticks may acquire the agent during feeding. Although previous studies have reported that white-tailed deer are a reservoir of the HGE agent, the role of white-tailed deer remains questionable, given that these studies were based on serological and PCR-based assays that did not examine the variable region of the 16S rRNA gene (17,27,28). Additional studies are needed to address the reservoir competency of white-tailed deer for both the HGE agent and AP-Variant 1.…”

Lyme Disease

“…13,14 Deer are not competent hosts for B. burgdorferi but are important in sustaining the life cycle of the vector ticks. In the United States, Lyme disease is transmitted only by Ixodes scapularis ticks (deer ticks) in the eastern and northern midwestern states and by I. pacificus ticks in the western United States.…”

“…They acquire B. burgdorferi by feeding on an infected animal and may transmit the infection to a human during a subsequent blood meal. 13,14 Transmission is most likely during the nymphal stage, since nymphs are abundant in the spring and early summer and are small and difficult to detect. 15 Correspondingly, the peak incidence of erythema migrans is during the spring and summer months.…”

“…3 Risk factors for Lyme disease include occupational and recreational exposure to fields and to woods in endemic areas, as well as outdoor activities such as gardening on residential properties near woodlands. 14,16 Ixodid ticks are also vectors for a number of other infectious agents that may produce coinfections with B. burgdorferi , with clinical manifestations that range from asymptomatic to severe and life-threatening (Table 1). 1 Although there has been concern about in utero transmission of B. burgdorferi , studies have shown no evidence of congenital Lyme disease.…”