Borrelia

Olsén, Björn

doi:10.1002/9780470344668.ch18

Cited by 11 publications

(4 citation statements)

References 70 publications

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“…Another assumption of the immune polarization hypothesis is that avian hosts should be able to mount immune responses to Borrelia spirochetes associated with such hosts. Indeed, contrary to earlier expectations based on the absence of clinical signs of Borrelia infection in avian hosts [ 69 ], the ability to mount host defenses against Borrelia spirochetes was confirmed for the key avian reservoir of bird-associated Borrelia spirochetes, the Eurasian blackbird [ 10 , 70 , 71 ].…”

Section: Discussioncontrasting

confidence: 86%

The Infection Rate of Bird-Feeding Ixodes ricinus Ticks with Borrelia garinii and B. valaisiana Varies with Host Haemosporidian Infection Status

2022

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Background: Birds are known to maintain and spread human pathogenic borreliae, but they are common hosts of diverse parasite communities, notably haemosporidians. Only a few studies examined whether tick infestation and/or Borrelia prevalences vary with hosts’ haemosporidian infection status. Methods: Here, we study whether Ixodes ricinus infestation rates and Borrelia infection rates in bird-feeding ticks vary according to haemosporidian infection status in a community of free-living avian tick hosts. Results: Birds of six avian species harbored the majority of ticks. Both the tick infestation prevalence and the intensity peaked during spring and summer, but while bird-feeding nymphs prevailed in spring, bird-feeding larvae dominated in summer. Almost half of the bird-feeding ticks were found to be positive for B. burgdorferi s.l. Although the majority of infections involved bird-associated B. garinii and B. valaisiana, B. garinii appears to be the dominant Borrelia strain circulating in locally breeding avian species. We detected a negative link between the hosts’ haemosporidian infection status and the Borrelia infection rate of bird-feeding ticks, but the association was dependent on the host’s age. Conclusions: Our results on tick infestation intensity support the idea that more immunologically vulnerable hosts harbor more ticks but suggest that different mechanisms may be responsible for tick infestation rates among immunologically naïve and experienced avian hosts. The results on Borrelia infection rates in bird-feeding ticks are consistent with studies revealing that intracellular parasites, such as haemosporidians, can benefit from the host immune system prioritizing immune responses against extracellular parasites at the expense of immune responses against intracellular parasites. The findings of our study urge for a more robust design of parasitological studies to understand the ecology of interactions among hosts and their parasites.

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Section: Discussioncontrasting

confidence: 86%

The Infection Rate of Bird-Feeding Ixodes ricinus Ticks with Borrelia garinii and B. valaisiana Varies with Host Haemosporidian Infection Status

2022

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“…In Europe, field studies have shown that birds have an important role in the ecology of B. burgdorferi s.l. because they often harbour Borrelia ‐infected ticks, including larvae, suggesting their competency as reservoirs (Mannelli et al ., ; Poupon et al ., ; Olsen, ; Michalik et al ., ; Taragel'ová et al ., ; Dubska et al ., ; Norte et al ., 2012b). However, very few studies performed xenodiagnostic experiments using bird species (Humair et al ., ; Kurtenbach et al ., ; Richter et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Blackbirds Turdus merula as competent reservoirs for Borrelia turdi and Borrelia valaisiana in Portugal: evidence from a xenodiagnostic experiment

Norte¹,

Carvalho

Núncio

et al. 2013

Environ Microbiol Rep

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To confirm that thrushes, such as blackbirds Turdus merula, play a role as reservoir for some Borrelia genospecies, we performed a xenodiagnostic experiment with blackbirds captured in a mixed wood located in Western Portugal where Borrelia turdi, an uncommon genospecies in Europe, was the most prevalent genospecies associated with birds. Two out of five birds harboured B. turdi infected Ixodes frontalis at the time of capture. Four out of five birds transmitted spirochaetes to Ixodes ricinus xenodiagnostic ticks: two birds transmitted Borrelia valaisiana to 25.7% and 10.5% of ticks, and two transmitted B. turdi to 6.4% and 5.4% of ticks. Our results showed that blackbirds transmit B. valaisiana and B. turdi to I. ricinus feeding larvae, acting as reservoir hosts for these genospecies in nature.

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“…Although current evidence suggests a role for seabirds in the global circulation of Lyme disease bacteria (Olsen et al 1995; Olsen 2003, 2007; Duneau et al 2008; Staszewski et al 2008), the importance of the marine cycle in Lyme disease epidemiology has yet to be explicitly considered (e.g. Kurtenbach et al 2006).…”

Section: Introductionmentioning

confidence: 99%

“…The marine cycle of LB was discovered more than a decade ago when Olsen et al (1993) demonstrated the circulation of one of the pathogenic species of the LB complex, Borrelia garinii , among seabird reservoirs via the tick Ixodes uriae . Although current evidence suggests a role for seabirds in the global circulation of Lyme disease bacteria ( Olsen et al 1995 ; Olsen 2003 , 2007 ; Duneau et al 2008 ; Staszewski et al 2008 ), the importance of the marine cycle in Lyme disease epidemiology has yet to be explicitly considered (e.g. Kurtenbach et al 2006 ).…”

Section: Introductionmentioning

confidence: 99%

Cryptic vector divergence masks vector‐specific patterns of infection: an example from the marine cycle of Lyme borreliosis

Gómez-Díaz

Doherty

Duneau

et al. 2010

Evolutionary Applications

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Vector organisms are implicated in the transmission of close to a third of all infectious diseases. In many cases, multiple vectors (species or populations) can participate in transmission but may contribute differently to disease ecology and evolution. The presence of cryptic vector populations can be particularly problematic as differences in infection can be difficult to evaluate and may lead to erroneous evolutionary and epidemiological inferences. Here, we combine site-occupancy modeling and molecular assays to evaluate patterns of infection in the marine cycle of Lyme borreliosis, involving colonial seabirds, the tick Ixodes uriae, and bacteria of the Borrelia burgdorferi s.l. complex. In this cycle, the tick vector consists of multiple, cryptic (phenotypically undistinguishable but genetically distinct) host races that are frequently found in sympatry. Our results show that bacterial detection varies strongly among tick races leading to vector-specific biases if raw counts are used to calculate Borrelia prevalence. These differences are largely explained by differences in infection intensity among tick races. After accounting for detection probabilities, we found that overall prevalence in this system is higher than previously suspected and that certain vector–host combinations likely contribute more than others to the local dynamics and large-scale dispersal of Borrelia spirochetes. These results highlight the importance of evaluating vector population structure and accounting for detection probability when trying to understand the evolutionary ecology of vector-borne diseases.

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Borrelia

Cited by 11 publications

References 70 publications

The Infection Rate of Bird-Feeding Ixodes ricinus Ticks with Borrelia garinii and B. valaisiana Varies with Host Haemosporidian Infection Status

The Infection Rate of Bird-Feeding Ixodes ricinus Ticks with Borrelia garinii and B. valaisiana Varies with Host Haemosporidian Infection Status

Blackbirds Turdus merula as competent reservoirs for Borrelia turdi and Borrelia valaisiana in Portugal: evidence from a xenodiagnostic experiment

Cryptic vector divergence masks vector‐specific patterns of infection: an example from the marine cycle of Lyme borreliosis

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