Novel Rickettsia and host records for argasid ticks, including Alveonasus cooleyi, on wild mammals in Baja California, Mexico.

We conducted surveillance of mammals to investigate their associations with argasid ticks and tick-borne pathogens. During 2021, a total of 20 wild carnivores and 57 lagomorphs were sampled, and 39 argasid ticks belonging to two species were collected. All mammals and ticks were tested by molecular assays to detect Borrelia and Rickettsia infections. Nine ticks identified as Otobius megnini were collected from two coyotes (Canis latrans) and 30 Alveonasus cooleyi (McIvor 1941) were collected from six bobcats (Lynx rufus) and one rabbit (Sylvilagus auduboni). We detected Rickettsia spp. DNA in 21 of the 27 (77.8%) tested Av. cooleyi and none of the O. megnini. No ticks were PCR-positive for borreliae and all mammals were PCR-negative for both pathogen genera. Phylogenetic analysis based on gltA, htrA, and 16 S rRNA targets revealed that all rickettsiae from Av. cooleyi clustered with ancestral group rickettsiae, likely representing a novel species of possibly endosymbiotic Rickettsia. The significance of Av. cooleyi and the newly identified Rickettsia sp. to the health of wildlife is unknown, and further work is indicated to determine whether they may be relevant to public health or carnivore conservation.

A new genus and new species of sucking louse (Phthiraptera: Anoplura: Enderleinellidae) from the particoloured flying squirrel (Hylopetes alboniger) in Laos, and an updated identification key to enderleinellid genera.

Hylophthirus spinosus, new genus and new species (Phthiraptera: Anoplura: Enderleinellidae), is described from specimens collected from the particoloured flying squirrel, Hylopetes alboniger in Khammouane Province, Laos (Lao Peoples Democratic Republic). Both sexes of the new louse are illustrated with stacked microphotographs, scanning electron micrographs and line drawings. An updated morphological identification key to the six genera (Atopophthirus, Enderleinellus, Hylophthirus, Microphthirus, Phthirunculus and Werneckia) now recognised within the family Enderleinellidae is presented. The new genus is unique within the Enderleinellidae in having massive spines (modified setae) on some abdominal sternites, partially bulbous 5th antennal segments, mesothoracic spiracles borne on protuberances and the morphology of the genitalia of both sexes. Tables showing all genera of sucking lice that include species parasitising sciurids (squirrels, chipmunks, susliks and marmots), and all known species of enderleinellids, with their known host associations and geographical distributions are included and briefly discussed in relation to the new genus and species.

Rickettsia species identified in adult, host-seeking Dermacentor occidentalis (Acari: Ixodidae) from Baja California, Mexico, and Oregon and Washington, United States.

The Pacific Coast tick (Dermacentor occidentalis Marx, 1892) is a frequently encountered and commonly reported human-biting tick species that has been recorded from most of California and parts of southwestern Oregon, southcentral Washington, and northwestern Mexico. Although previous investigators have surveyed populations of D. occidentalis for the presence of Rickettsia species across several regions of California, populations of this tick have not been surveyed heretofore for rickettsiae from Baja California, Oregon, or Washington. We evaluated 1,367 host-seeking, D. occidentalis adults collected from 2015 to 2022 by flagging vegetation at multiple sites in Baja California, Mexico, and Oregon and Washington, United States, using genus- and species-specific assays for spotted fever group rickettsiae. DNA of Rickettsia 364D, R. bellii, and R. tillamookensis was not detected in specimens from these regions. DNA of R. rhipicephali was detected in D. occidentalis specimens obtained from Ensenada Municipality in Baja California and southwestern Oregon, but not from Washington. All ompA sequences of R. rhipichephali that were amplified from individual ticks in southwestern Oregon were represented by a single genotype. DNA of the Ixodes pacificus rickettsial endosymbiont was amplified from specimens collected in southwestern Oregon and Klickitat County, Washington; to the best of our knowledge, this Rickettsia species has never been identified in D. occidentalis. Collectively, these data are consistent with a relatively recent introduction of Pacific Coast ticks in the northernmost extension of its recognized range.

Description of two new species in the Ixodes ricinus complex from the New World (Acari: Ixodidae), and redescription of Ixodes affinis Neumann, 1899.

Ixodes chacoensis n. sp. is described based on males, females, nymphs and larvae collected from vegetation, ungulates and passerine birds in northeastern Argentina. Ixodes affinis Neumann, 1899 is redescribed based on the original type specimens (females) from Leopardus pardalis, and from recently collected specimens from Costa Rica. Ixodes keiransi n. sp., previously treated as North American populations of Ixodes affinis, is described based on males and females from carnivores and ungulates from the southeastern United States. Concatenated total evidence phylogenetics based on combined DNA sequence analyses from mitochondrial genes (12SrDNA, 16SrDNA and COI) and a nuclear gene (ITS2) corroborate the recognition of these species.