https://www.mdpi.com/2227-9032/8/1/59/htm

Healthcare 2020, 8(1), 59; https://doi.org/10.3390/healthcare8010059

Article

Monitoring of Nesting Songbirds Detects Established Population of Blacklegged Ticks and Associated Lyme Disease Endemic Area in Canada

Abstract

This study provides a novel method of documenting established populations of bird-feeding ticks. Single populations of the blacklegged tick, Ixodes scapularis, and the rabbit tick, Haemaphysalis leporispalustris, were revealed in southwestern Québec, Canada. Blacklegged tick nymphs and, similarly, larval and nymphal rabbit ticks were tested for the Lyme disease bacterium, Borrelia burgdorferi sensu lato (Bbsl), using PCR and the flagellin (flaB) gene, and 14 (42%) of 33 of blacklegged tick nymphs tested were positive. In contrast, larval and nymphal H. leporsipalustris ticks were negative for Bbsl. The occurrence of Bbsl in I. scapularis nymphs brings to light the presence of a Lyme disease endemic area at this songbird nesting locality. Because our findings denote that this area is a Lyme disease endemic area, and I. scapularis is a human-biting tick, local residents and outdoor workers must take preventive measures to avoid tick bites. Furthermore, local healthcare practitioners must include Lyme disease in their differential diagnosis.
___________________
**Comment**
The article is quick to point out that while THIS study didn’t find Bbsl in H. leporsipalustris ticks (rabbit tick), past research has.  If you read the entire study you will see the following excerpts:

4.4. H. leporispalustris Vector Competency

In this study, we did not identify Bbsl in H. leporispalustris ticks. However, Banerjee et al. detected Lyme disease spirochetes in H. leporispalustris ticks collected from a snowshoe hare, Lepus americanus, in northern Alberta [47]. As well, Scott et al. discovered Borrelia lanei-like spirochetes and a Babesia divergens-like piroplasm concurrently in a H. leporispalustris (female) collected from an eastern cottontail, Sylvilagus floridanus, in southern Manitoba [48]. Scott & Durden provide the first record of a Bbsl-positive H. leporispalustris (nymph) collected from an avian host (Swainson’s Thrush) in Canada [14]. Previously, Scott et al. found Bbsl in a H. leporispalustris larva parasitizing a passerine (Canada Warbler) in Québec suggesting that this tick species is a reservoir-competent host [8]. During southbound, fall migration in Canada, larval and nymphal H. leporispalustris frequently parasitize passerines, and are widely dispersed in southern regions.

4.5. Ticks Co-infest Songbirds

One Veery was co-infested with H. leporispalustris (one nymph and one larva), and I. scapularis (two nymphs). Not only is there a breeding colony of I. scapularis present in this Laurentian River basin, an established population of H. leporispalustris is also there. Since these ixodid ticks were collected during the nesting and fledgling period, this bird parasitism denotes a cohabitation of two tick species in this sylvan locale, and signifies that these two tick species are sympatric. The Veery has trans-border and trans-equatorial migration during its northward spring flight, and has a breeding range in southern Canada, including southwestern Québec and northern United States; the wintering range is in central and southeastern Brazil (Figure 4). During the breeding, nesting, and fledgling period, Veeries have localized activity in juxtaposition to the stationary nest. When the young have fledged the nest, these passerines replenish their fat reserves, and prepare for the southbound trek to wintering ranges in southern latitudes during August and September. In late July, they typically moult in preparation for the southbound marathon flight.
Why this is important:  because we continue to be told that ONLY the black legged tick transmits Lyme to humans.  Here we are told transmission by the rabbit tick (H. leporispalustris) is rare:  https://en.wikipedia.org/wiki/Haemaphysalis_leporispalustris
The following pathogens have been found in the rabbit tick:

The two studies used as references in the wikipedia article state the following about the rabbit tick.  While Lyme (borrelia) isn’t mentioned (but should be), Rickettsia is:

Our results support a possible role of H. leporispalustris in the enzootic maintenance of R. rickettsii in Latin America, as previously suggested by earlier works.  https://link.springer.com/article/10.1007%2Fs10493-008-9220-4

We have been able to isolate 2 strains of rickettsiae from the rabbit tick , indistinguishable from isolated from humans in our country (Costa Rica). http://www.ajtmh.org/content/journals/10.4269/ajtmh.1985.34.564

Regarding borrelia (Lyme) in the rabbit tick please note that in 4.4 above, Scott et al. found Bbsl in a H. leporispalustris larva parasitizing a Warbler suggesting that this tick species is a reservoir-competent host. In essence, the rabbit tick clearly has borrelia strains within it.  And further, during southbound, fall migration in Canada, larval and nymphal H. leporispalustris frequently parasitize passerines, and are widely dispersed in southern regions.  In essence, ticks with borrelia are infecting birds that are then going South and spreading their pathogens there.

Let’s say hypothetically that the rabbit tick is incapable of transmitting Lyme to humans.  Who’s to say that an animal that is co-infested with both black-legged ticks & rabbit ticks (as happened in this study) can’t then harbor all of these pathogens simultaneously that could in the the future be be transmitted to humans through the feedings of successive ticks?
I’m just a simple woman, but it appears to me that nobody is considering this.  They would rather look at old studies that state emphatically that only certain ticks in certain locations can transmit to humans and then smugly send patient after patient home with an anti-depressant.  Either we are all nuts or lying, OR something is happening out there that isn’t being picked up.  I vote for the latter.
The study shows that established borrelia infested ticks feeding on songbirds are spreading borrelia (and other things I’m sure) into new areas – far away from where they started and rodents are maintaining the cycle all year round.  
There is no “safe” time of the year.
Lastly, of epidemiological merit 100% of tested American Robins were positive for Bbsl.