Nyt fra tidsskrifterne

Case report…

Infection and Immunity, Ahead of Print. …

by Ariane Dumas, Catherine Bouchard, Antonia Dibernardo, Pierre Drapeau, L. Robbin Lindsay, Nicholas H. Ogden, Patrick A. Leighton

Ixodes scapularis ticks are expanding their range in parts of northeastern North America, bringing with them pathogens of public health concern. While rodents like the white-footed mouse, Peromyscus leucopus, are considered the primary reservoir of many emerging tick-borne pathogens, the contribution of birds, as alternative hosts and reservoirs, to local transmission cycles has not yet been firmly established. From 2016 to 2018, we collected host-seeking ticks and examined rodent and bird hosts for ticks at 48 sites in a park where blacklegged ticks are established in Quebec, Canada, in order to characterize the distribution of pathogens in ticks and mammalian and avian hosts. We found nearly one third of captured birds (n = 849) and 70% of small mammals (n = 694) were infested with I. scapularis. Five bird and three mammal species transmitted Borrelia burgdorferi to feeding larvae (n larvae tested = 2257) and we estimated that about one fifth of the B. burgdorferi-infected questing nymphs in the park acquired their infection from birds, the remaining being attributable to mice. Ground-foraging bird species were more parasitized than other birds, and species that inhabited open habitat were more frequently infested and were more likely to transmit B. burgdorferi to larval ticks feeding upon them. Female birds were more likely to transmit infection than males, without age differentiation, whereas in mice, adult males were more likely to transmit infection than juveniles and females. We also detected Borrelia miyamotoi in larvae collected from birds, and Anaplasma phagocytophilum from a larva collected from a white-footed mouse. This study highlights the importance of characterising the reservoir potential of alternative reservoir hosts and to quantify their contribution to transmission dynamics in different species assemblages. This information is key to identifying the most effective host-targeted risk mitigation actions.

Infection and Immunity, Ahead of Print. …

Infection and Immunity, <a href='https://journals.asm.org/toc/iai/0/ja'>Volume 0, Issue ja</a>, -Not available-. …

Journal Name: The American Journal of Tropical Medicine and HygieneVolume: 106Issue: 1Pages: 45-46

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AbstractBackgroundQuantiFERON enzyme-linked immunosorbent assay (ELISA; Qiagen) with Borrelia burgdorferi peptide antigens was previously shown to reliably detect interferon-γ (IFN-γ) in blood samples from adult patients with early Lyme disease and the response disappeared rapidly after treatment. We evaluated the response before and after appropriate antibiotic therapy in adolescent and adult subjects with more diverse stages of the illness.MethodsBlood was obtained from patients with clinician-identified Lyme disease with constitutional complaints, erythema migrans, nerve palsy, cardiac abnormality, or arthritis before (n = 68) and 6 weeks (n = 46) and 6 months (n = 45) after therapy. The sera were tested for Lyme disease by standard 2-tiered testing (STTT) and anti–C6 antibodies by ELISA and the levels of IFN-γ in the blood samples were detected by QuantiFERON ELISA.ResultsA positive STTT result supported the clinical diagnosis of 37 (54%) subjects and anti-C6 antibodies were detected in 45 (66%) subjects, including 36 (97%) STTT-positive subjects, and the responses often persisted or expanded after antibiotic therapy. IFN-γ was detected in 49 (72%) subjects prior to treatment and the response most often significantly decreased 6 weeks (P = .007) or 6 months (P = .001) after treatment.ConclusionsThe QuantiFERON ELISA reliably detected IFN-γ in blood samples from adult and adolescent patients with varying stages of Lyme disease and the response disappeared rapidly after treatment. Additional studies to more critically evaluate clinical utility as a laboratory test for diagnosis and confirmation of effective therapy are warranted.