Unique Strain of Rickettsia parkeri Associated with the Hard Tick Dermacentor parumapertus Neumann in the Western United States.

In 1953, investigators at the Rocky Mountain Laboratories in Hamilton, MT, described the isolation of a spotted fever group Rickettsia (SFGR) species from Dermacentor parumapertus ticks collected from black-tailed jackrabbits (Lepus californicus) in northern Nevada. Several decades later, investigators characterized this SFGR (designated the parumapertus agent) by using mouse serotyping methods and determined that it represented a distinct rickettsial serotype closely related to Rickettsia parkeri; nonetheless, the parumapertus agent was not further characterized or studied. To our knowledge, no isolates of the parumapertus agent remain in any rickettsial culture collection, which precludes contemporary phylogenetic placement of this enigmatic SFGR. To rediscover the parumapertus agent, adult-stage D. parumapertus ticks were collected from black-tailed jackrabbits shot or encountered as roadkills in Arizona, Utah, or Texas from 2011 to 2016. A total of 339 ticks were collected and evaluated for infection with Rickettsia species. Of 112 D. parumapertus ticks collected in south Texas, 16 (14.3%) contained partial ompA sequences with the closest identity (99.6%) to Rickettsia sp. strain Atlantic rainforest Aa46, an SFGR that is closely related or identical to an SFGR species that causes a mild rickettsiosis in several states of Brazil. A pure isolate, designated strain Black Gap, was cultivated in Vero E6 cells, and sequence analysis of the rrs, gltA, sca0, sca5, and sca4 genes also revealed the closest genetic identity to Rickettsia sp. Atlantic rainforest Aa46. Phylogenetic analysis of the five concatenated rickettsial genes place Rickettsia sp. strain Black Gap and Rickettsia sp. Atlantic rainforest Aa46 with R. parkeri in a distinct and well-supported clade.IMPORTANCE We suggest that Rickettsia sp. Black Gap and Rickettsia sp. Atlantic rainforest Aa46 represent nearly identical strains of R. parkeri and that Rickettsia sp. Black Gap or a very similar strain of R. parkeri represents the parumapertus agent. The close genetic relatedness among these taxa, as well as the response of guinea pigs infected with the Black Gap strain, suggests that R. parkeri Black Gap could cause disease in humans. The identification of this organism could also account, at least in part, for the remarkable differences in severity ascribed to Rocky Mountain spotted fever (RMSF) among various regions of the American West during the early 20th century. We suggest that the wide variation in case fatality rates attributed to RMSF could have occurred by the inadvertent inclusion of cases of milder disease caused by R. parkeri Black Gap.

Exploring public health education's integration of critical race theories: A scoping review.

Introduction: Public health has declared a commitment toward diversity as a whole, with a commitment toward addressing and dismantling racism being at the forefront. Although public health has admirably taken on this mission, and the foundational principles of public health align with social justice and health equity, public health as a discipline is vastly behind other fields in integrating and utilizing critical race theorizations. Of particular concern is the lack of critical race theorization within public health education materials. Public health education serves as a precursor to public health practice and situates topics and competencies that are essential to one's foundational public health knowledge and skillset, thus the use of strong theoretical groundings is critical in public health education. Objectives: Therefore, to explore the current landscape of public health educational research that employs critical race theories, this study sought to conduct a scoping review investigating the current literature of public health pedagogical, instructional, and curricular efforts that utilize race and antiracist theorization principles as a means to administer public health education. More specifically, we sought to investigate how have faculty and instructors published their integration of race theorization in public health curriculum/instruction within the United States since 2011. Results: We found 18 examples from peer-reviewed literature of curricular, pedagogical, or instructional practices and strategies that integrate critical theories of race, including contemplative pedagogy (n = 1), antiracism (n = 3), Public Health Critical Race praxis (n = 4), Critical Race (n = 5), critical service-learning/community engagement (n = 2), ethnic studies (n = 1), and intersectionality (n = 2). Conclusion: These articles present a wide breadth of innovative approaches to infusing critical race studies within public health higher education, ranging from individual assignments to course design and implementation to institutional culture change, thus demonstrating the multifaceted nature of critical race studies within micro-learning communities and macro-discipline practices. Identifying theoretically grounded, exemplary models and scholarly recommendations of pedagogical, instructional, and curricular practices provides readers the opportunity to borrow from successful practices and implement concepts of race, racism, antiracism, intersectionality, and more into their classrooms.

Molecular Phylogeny of Dermacentor parumapertus (Acari: Ixodidae) from Two Locations Within Its Geographical Range.

Dermacentor parumapertus Neumann (Acari: Ixodidae) is a rather obscure tick found on jackrabbits in the western United States and parts of Canada and Mexico. Specimens from the northern part of their range are consistently different morphologically from ones found in southern and eastern parts of their range (particularly west Texas), leading some researchers to declare the southern form a variety or subspecies. This study examined field-collected adult D. parumapertus from two main locations-Utah and Texas-within its geographic distribution to ascertain the degree of genetic divergence in the two populations based upon both nuclear and mitochondrial DNA sequences. In total, 30 D. parumapertus were analyzed by PCR using both mtDNA and nDNA genes, and one D. nitens was included for comparison. Trees were constructed for all mtDNA genes individually, as well as after concatenating mtDNA (COI, COII, 12S) and nDNA (2 ITS2 primers), respectively. All constructed trees were exported to FigTree v1.4.3 and TreeGraph v2.14.1-771 beta for visualization. The majority of the Utah and Texas populations of D. parumapertus separated molecularly in both mtDNA and nDNA trees; however, analysis with mtDNA genes showed that 3/13 (23%) of Utah tick specimens were removed molecularly from other specimens collected at the same location. Thus, there was not enough evidence to declare these two disparate and morphologically different populations as distinct and separate species.

Morphometric Analysis of Adult Dermacentor parumapertus Neumann (Acari: Ixodidae) From Various Locations Within its Geographical Range.

Dermacentor parumapertus Neumann (Acari: Ixodidae), a tick primarily associated with rabbits which occurs over much of the western United States, has a fairly large north-to-south distribution, being found from central Idaho southward into northern Mexico. This mostly obscure tick species has recently been the focus of attention due to the discovery of a unique strain of Rickettsia parkeri associated with it which appears closely related to a Rickettsia sp. found in the Atlantic rainforest of Brazil. Historically, a morphological variety of this species was reported in the literature based on significant variation in ornamentation of the tick throughout its range. This study examines several key morphological characters to determine if there are indeed more than one distinct population of this species throughout its range.