During August 13–14, 2023, a new SARS-CoV-2 Omicron subvariant with a large number of mutations compared with previously circulating BA.2 variants (>30 amino acid differences in its spike protein) was identified by genomic sequencing in Denmark and Israel and subsequently designated BA.2.86 (1,2). Given near-simultaneous detections in multiple countries, including the United States, further information was needed regarding geographic spread of BA.2.86. Since January 2022, submissions to SARS-CoV-2 sequence repositories have declined by 95%,* substantially decreasing global capacity to monitor new variants. To fill gaps in global surveillance, CDC’s Traveler-based Genomic Surveillance (TGS) program was developed to provide early warning of new variants entering the United States by collecting samples from arriving international travelers (3).

The larva of the ixodid tick Dermacentor parumapertus Neumann, chiefly a parasite of hares and rabbits, is redescribed using scanning electron micrographs of seven specimens derived from two engorged females collected from two black-tailed jackrabbits, Lepus californicus, at the Black Gap Wildlife Management Area, Brewster County, southwestern Texas. The use of chaetotaxy for separating the genera of Ixodidae is discussed, and a morphological key is provided for separating the larvae of D. parumapertus from those of five other Dermacentor species with partly sympatric geographic ranges. © 2023 Systematic and Applied Acarology Society. All rights reserved.

Beginning December 6, 2021, all international air passengers boarding flights to the United States were required to show either a negative result from a SARS-CoV-2 viral test taken ≤1 day before departure or proof of recovery from COVID-19 within the preceding 90 days (1). As of June 12, 2022, predeparture testing was no longer mandatory but remained recommended by CDC (2,3). Various modeling studies have estimated that predeparture testing the day before or the day of air travel reduces transmission or importation of SARS-CoV-2 by 31%-76% (4-7). Postarrival SARS-CoV-2 pooled testing data from CDC's Traveler-based Genomic Surveillance program were used to compare SARS-CoV-2 test results among volunteer travelers arriving at four U.S. airports during two 12-week periods: March 20-June 11, 2022, when predeparture testing was required, and June 12-September 3, 2022, when predeparture testing was not required. In a multivariable logistic regression model, pooled nasal swab specimens collected during March 20-June 11 were 52% less likely to be positive for SARS-CoV-2 than were those collected during June 12-September 3, after adjusting for COVID-19 incidence in the flight's country of origin, sample pool size, and collection airport (adjusted odds ratio [aOR] = 0.48, 95% CI = 0.39-0.58) (p<0.001). These findings support predeparture testing as a tool for reducing travel-associated SARS-CoV-2 transmission and provide important real-world evidence that can guide decisions for future outbreaks and pandemics.

OBJECTIVE: Determine the incidence of SARS-CoV-2 infection among healthcare personnel (HCP) and assess occupational risks for SARS-CoV-2 infection. DESIGN: Prospective cohort of HCP followed for 6-months from May-December 2020. SETTING: Large academic healthcare system including four hospitals and affiliated clinics in Atlanta, GA. PARTICIPANTS: HCP, including those with and without direct patient care activities, working during the COVID-19 pandemic. METHODS: Incident SARS-CoV-2 infections were determined through serologic testing for SARS-CoV-2 IgG at enrollment, 3 and 6 months. HCP completed monthly surveys regarding occupational activities. Multivariable logistic regression was used to identify occupational factors that increased the risk of SARS-CoV-2 infection. RESULTS: Of the 304 evaluable HCP that were seronegative at enrollment, 26 (9%) seroconverted for SARS-CoV-2 IgG by 6 months. Participants self-identified predominantly as White (n=219, 73%), nurses (n=119, 40%), and working in inpatient medical/surgical floors (n=121, 40%). In a multivariable analysis, HCP who identified as Black were more likely to seroconvert than HCP who identified as White (odds ratio 4.5, 95% confidence interval 1.3-14.2). Increased risk for SARS-CoV-2 infection was not identified for any occupational activity, including spending >50% of a typical shift at a patient's bedside, working in COVID-19 units, or performing/being present for aerosol generating procedures (AGPs). CONCLUSIONS: In our study cohort of HCP working in an academic healthcare system, <10% had evidence of SARS-CoV-2 infection over six months. No specific occupational activities were identified as increasing risk for SARS-CoV-2 infection.

Among 353 healthcare personnel in a longitudinal cohort in four hospitals in Atlanta, GA (May-June 2020), 23 (6.5%) had SARS-CoV-2 antibodies. Spending >50% of a typical shift at bedside (OR 3.4, 95% CI: 1.2-10.5) and Black race (OR 8.4, 95% CI: 2.7-27.4) were associated with SARS-CoV-2 seropositivity.

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.

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.

In 1953, investigators at the Rocky Mountain Laboratories in Hamilton, Montana, described the isolation of a spotted fever group Rickettsia (SFGR) species from Dermacentor parumapertus collected from black-tailed jackrabbits (Lepus californicus) in northern Nevada. Several decades later, investigators characterized this SFGR by using mouse serotyping methods and determined that it represented a distinct rickettsial serotype, related closely to Rickettsia parkeri; nonetheless, the parumapertus agent was not further characterized or studied. No extant isolates of the parumapertus agent remain in any rickettsial culture collection around the world 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 road-kills in Arizona, Utah, or Texas during 2011-2016. A total of 339 ticks were collected and evaluated for infection with Rickettsia species. From 112 D. parumapertus collected in south Texas, 16 (14.3%) contained partial ompA sequences with closest identity (99.6%) to Rickettsia sp. Atlantic rainforest, a recently identified pathogenic SFGR 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 closest genetic identity to Rickettsia sp. Atlantic rainforest. Phylogenetic analysis of the five concatenated rickettsial genes place Rickettsia sp. Black Gap and Rickettsia sp. Atlantic rainforest with R. parkeri in a distinct and well-supported clade.Importance. We suggest that Rickettsia sp. Black Gap and Rickettsia sp. Atlantic rainforest 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. Close genetic relatedness among these taxa, as well as the response of guinea pigs infected with Black Gap strain, suggest that R. parkeri Black Gap could cause disease in humans. The identification of this organism could also account, at least in part, for remarkable differences in severity ascribed to RMSF among various regions of the American West during the early 20th century. We suggest that 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.