Efficient Transmission of Borrelia burgdorferi Between Cofeeding Ixodes ricinus Ticks (Acari: Ixodidae)

Abstract

Feeding ticks are generally spatially distributed in clusters on vertebrate hosts. To test the effect of clustering on transmission of a tick-borne pathogen, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner-infected Ixodes ricinus L. nymphs and uninfected I. ricinus larvae were allowed to feed together in retaining chambers on uninfected AKR/N mice. Engorged infective nymphs dropped off at days 5, 6, and 7, and the 1st infected larvae that fed in the chambers together with the infected nymphs dropped off at day 5. In contrast, ear biopsies and xenodiagnostic larvae placed on the head remained negative during that period. These results suggest that a cofeeding transmission occurred between B. hurgdorferi-infected ticks and noninfected ones in the absence of a disseminated infection. Further investigations are being undertaken to determine whether the mechanism responsible for this cofeeding transmission is similar to that described previously with virus-infected ticks.

Importance of Common Wall Lizards in the Transmission Dynamics of Tick-Borne Pathogens in the Northern Apennine Mountains, Italy

“…Since transovarial transmission of B. burgdorferi s.l. is unlikely [43], the finding of genospecies other than B. lusitaniae in attached larvae may be explained by the involvement of lizards in their maintenance (systemic infection), by a precedent interrupted blood-meal taken on an infected reservoir host, or by the cofeeding transmission among larvae and nymphs feeding in close proximity [17]. This last hypothesis is countered by the low coinfestation by I. ricinus nymphs and larvae observed on our lizards; all these possible explanations deserve further investigations anyway.…”

Borrelia Burgdorferi Sensu Lato Detected in Skin of Norwegian Mountain Hares (Lepus Timidus) Without Signs of Dissemination

“…Because transovarial transmission of B. burgdorferi s.l. is rare, infection prevalence in unfed larvae is usually 1-3% (Gern et al, 1998). As the larval infection occurred in the absence of a detectable spirochetemia in the hares, spirochetes may remain localized in the skin of hares, without causing systemic infection.…”

“…The spirochetes may then be transmitted from the skin to feeding ticks. However, the infected larvae may also have acquired the bacteria from cofeeding ticks (Gern and Rais, 1996). In the absence of nymphal and adult ticks feeding on one hare shot at Oksøy, no larvae were infected by B. burgdorferi s.l., possibly supporting the theory of transmission by cofeeding.…”

“…through feeding on reservoir hosts. Many host species have been shown to be capable of infecting I. ricinus with B. burgdorferi s.l., and small rodents and birds are considered to be the main reservoir hosts for this spirochete in Europe (Gern et al, 1998). However, a nonreservoir host may also contribute to the risk of acquiring tick-borne disease merely by contributing to the maintenance of the tick population.…”

Chemotactic migration of the Lyme disease spirochete (Borrelia burgdorferi) to salivary gland extracts of vector ticks.

“…10,11 Due to the long-lasting feeding process of ticks, tick salivary gland and its related secretions must play an important role not only in the spirochete transmission, but also in the acquisition of spirochetes. Spirochetes have been shown to be delivered via salivary dissemination by vector ticks, 12 and the efficiency of acquisition of spirochetes by vector ticks correlates directly with the duration of attachment of the feeding ticks.…”