Morphological and molecular description of Ixodes woyliei n. sp. (Ixodidae) with consideration for co-extinction with its critically endangered marsupial host

Background Taxonomic identification of ticks obtained during a longitudinal survey of the critically endangered marsupial, Bettongia penicillata Gray, 1837 (woylie, brush-tailed bettong) revealed a new species of Ixodes Latrielle, 1795. Here we provide morphological data for the female and nymphal life stages of this novel species (Ixodes woyliei n. sp.), in combination with molecular characterisation using the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). In addition, molecular characterisation was conducted on several described Ixodes species and used to provide phylogenetic context. Results Ixodes spp. ticks were collected from the two remaining indigenous B. penicillata populations in south-western Australia. Of 624 individual B. penicillata sampled, 290 (47%) were host to ticks of the genus Ixodes; specifically I. woyliei n. sp., I. australiensis Neumann, 1904, I. myrmecobii Roberts, 1962, I. tasmani Neumann, 1899 and I. fecialis Warburton & Nuttall, 1909. Of these, 123 (42%) were host to the newly described I. woyliei n. sp. In addition, 268 individuals from sympatric marsupial species (166 Trichosurus vulpecula hypoleucus Wagner, 1855 (brushtail possum), 89 Dasyurus geoffroii Gould, 1841 (Western quoll) and 13 Isoodon obesulus fusciventer Gray, 1841 (southern brown bandicoot)) were sampled for ectoparasites and of these, I. woyliei n. sp. was only found on two I. o. fusciventer. Conclusions Morphological and molecular data have confirmed the first new Australian Ixodes tick species described in over 50 years, Ixodes woyliei n. sp. Based on the long-term data collected, it appears this tick has a strong predilection for B. penicillata, with 42% of Ixodes infections on this host identified as I. woyliei n. sp. The implications for this host-parasite relationship are unclear but there may be potential for a future co-extinction event. In addition, new molecular data have been generated for collected specimens of I. australiensis, I. tasmani and museum specimens of I. victoriensis Nuttall, 1916, which for the first time provides molecular support for the subgenus Endopalpiger Schulze, 1935 as initially defined. These genetic data provide essential information for future studies relying on genotyping for species identification or for those tackling the phylogenetic relationships of Australian Ixodes species

High prevalence of Rickettsia gravesii sp. nov. in Amblyomma triguttatum collected from feral pigs

A survey of ectoparasites on feral pigs identified two commonly occurring ixodid tick species; Amblyomma triguttatum triguttatum and Ixodes australiensis. Molecular screening of A. t. triguttatum and I. australiensis for the presence of Rickettsia species detected the presence of rickettsiae belonging to the Spotted Fever Group (SFG) in 78.4% of screened A. t. triguttatum. None of the screened I. australiensis were positive for rickettsiae. Sequence analysis of the gltA and ompA loci of positive Rickettsia isolates were 100% homologous to the newly described species Rickettsia gravesii sp. nov. BWI-1. Serological screening of feral pigs detected antibodies to SFG Rickettsia in 50% of serum samples tested. These findings suggest that A. t. triguttatum is a vector/reservoir for R. gravesii sp. nov

Seroepidemiological study of outdoor recreationists' exposure to spotted fever group rickettsia in Western Australia

Bushland activity has previously been linked to rickettsial exposure in eastern and central regions of Australia, whereas little is known about the risks in Western Australia. The isolation of Rickettsia gravesii sp. nov. from Amblyomma triguttatum ticks and anecdotal reports of low-grade illness among bush recreationists raised the possibility of rickettsial transmission in the State. This study investigated rickettsial seroprevalence and potential risk of exposure to the spotted fever group rickettsiae in rogainers. Our results showed that rogainers active in the bush had a significantly higher risk of seropositivity (immunofluorescence total antibody titer ≥128) for the spotted fever group Rickettsia (odds ratio [OR] = 14.02, 95% confidence interval [CI] = 1.38-142.07) compared with a reference population, the overall seroprevalence in the rogainer group being 23.1%

Differential activities of alpha/beta IFN subtypes against influenza virus in vivo and enhancement of specific immune responses in DNA vaccinated mice expressing haemagglutinin and nucleoprotein

Vaccines are urgently needed to elicit immunity to different influenza virus strains. DNA vaccines can elicit partial protective immunity, however their efficacy requires improvement. We assessed the capacity of individual type I IFN multigene family members as subtype transgenes to abrogate influenza virus replication in a vaccination/challenge mouse model. Differences in antiviral efficacy were found among the subtypes with IFNA5 and IFNA6 being most effective, while IFNA1 was the least effective in reducing lung virus replication. Mice vaccinated with combinatorial HA/IFNA6 or NP/IFNA6 showed reduced lung viral titres, clinical score, body weight loss, and pulmonary tissue damage compared to IFNA6, HA, or NP viral vaccination alone. In addition, IFNA6 increased IgG2a titres with upregulation of IFN-gamma response in the respiratory tract. We conclude that IFN-alpha 6 has antiviral and immunomodulatory effects, which improve efficacy of DNA vaccines for enhanced control of influenza

Update on tick-borne rickettsioses around the world : a geographic approach [plus erratum]

Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These zoonoses are among the oldest known vector-borne diseases. However, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. Several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections, and novel Rickettsia species of undetermined pathogenicity continue to be detected in or isolated from ticks around the world. This remarkable expansion of information has been driven largely by the use of molecular techniques that have facilitated the identification of novel and previously recognized rickettsiae in ticks. New approaches, such as swabbing of eschars to obtain material to be tested by PCR, have emerged in recent years and have played a role in describing emerging tick-borne rickettsioses. Here, we present the current knowledge on tick-borne rickettsiae and rickettsioses using a geographic approach toward the epidemiology of these diseases

The effect of sample site, illness duration, and the presence of pneumonia on the detection of SARS-CoV-2 by real-time reverse transcription PCR

10.1093/ofid/ofaa335Open Forum Infectious Diseases79ofaa33

Whole blood immunophenotyping uncovers immature neutrophil-to-VD2 T-cell ratio as an early marker for severe COVID-19

10.1038/s41467-020-19080-6Nature Communications111524

Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients

10.1038/s41467-020-16670-2Nature Communications111280