February 2020

Emerging Infectious Diseases Journal

Highlights: Emerging Infectious Diseases, Vol. 26, No.2, February 2020

The articles of interest summarized below will appear in the February 2020 issue of Emerging Infectious Diseases, CDC’s monthly peer-reviewed public health journal. The articles are embargoed until January 15, 2020, at noon Eastern time.

Important Note: Not all articles that EID publishes represent work done at CDC or by CDC staff. In your stories, please clarify whether a study was conducted by CDC (“a CDC study”) or by another institution (“a study published by CDC in the EID journal”). Opinions expressed by authors contributing to EID do not necessarily reflect the opinions of CDC or the institutions with which the authors are affiliated.

EID requests that, when possible, you link directly to the actual journal article in your stories. Once the embargo lifts, this month’s articles will be found in this month’s articles will be found in the Early Release section of the EID website at https://wwwnc.cdc.gov/eid/early-release.

1.     Characteristics of Patients with Acute Flaccid Myelitis, United States, 2015–2018, Nilay McLaren et al.

Acute flaccid myelitis (AFM) is a serious condition characterized by the onset of limb weakness or paralysis and is a known complication of infection with certain viruses (e.g., polioviruses). After the elimination of poliovirus in the United States, AFM caused by poliovirus became much less common. However, sporadic, poliovirus-negative cases continued to occur. In 2014, an unusual cluster of AFM in children was identified in Colorado. National surveillance revealed heightened AFM activity in 2016 and 2018. During those years, peak illness onset occurred during August–October. In contrast, in 2015 and 2017, the number of AFM cases remained low and did not vary by season. What occurred in 2014 was new: an alternating pattern of high activity one year and low activity the next (i.e., peak and nonpeak years). Researchers hypothesized that if a single pathogen were responsible for most AFM cases in peak years, cases of illness onset in these years probably would look different (in terms of signs and symptoms) from cases occurring in nonpeak years. They then compared characteristics of AFM cases in peak versus nonpeak years to evaluate their hypothesis. They found that AFM patients in peak years were younger than those in nonpeak year. A higher percentage of patients in peak years than nonpeak years had elevated white blood cell counts, upper extremity involvement, and an illness preceding limb weakness, and were positive for enterovirus or rhinovirus RNA. Appropriate clinical management of AFM relies in part on healthcare providers recognizing the symptoms of AFM and thoroughly documenting and reporting AFM cases to public health authorities, regardless of the pathogen implicated by test results. National AFM surveillance data can then be used to further characterize yearly variations in AFM cases and help explain this emerging illness.

Contact: CDC Media Relations; phone: 404-639-3286 or email: media@cdc.gov

2.   Rickettsia parkeri and Candidatus Rickettsia andeanae in Amblyomma maculatum Group Ticks, Bruce H. Noden et al.

Rickettsia parkeri, a bacterium in the spotted fever group Rickettsia (SFGR), is transmitted by ticks and causes disease in humans throughout much of the southern United States. Until recently, all test-positive adult Gulf Coast ticks (Amblyomma maculatum) in Oklahoma had been infected with Candidatus Rickettsia andeanae (a recently identified but incompletely characterized SFGR). The absence of R. parkeri in Oklahoma is surprising because it was detected in Gulf Coast ticks collected in Arkansas and Texas. Given the importance of the Gulf Coast tick across the southern United States and its presence in Oklahoma since the 1940s, researchers collected these ticks in the Oklahoma City metropolitan area during the spring and summer months of 2017 and 2018 and tested them for Rickettsia bacteria. Of the 172 ticks tested, 4 (2.3%) were infected with R. parkeri and 118 (68.6%) with Candidatus Rickettsia andeanae. In some regions of the United States, R. parkeri prevalence in Gulf Coast ticks is low but Candidatus R. andeanae prevalence is high, suggesting that the high prevalence of Candidatus R. andeanae in Oklahoma ticks might interfere with R. parkeri development, limiting its distribution and its ability to cause disease. Nevertheless, the presence of R. parkeri in the largest metropolitan area of Oklahoma warrants thorough case evaluation of future SFGR cases in the region, as well as further research on R. parkeri prevalence and risk factors for humans who encounter ticks infected by this pathogen.

Contact: Bruce Noden, Oklahoma State University Stillwater, email: bruce.noden@okstate.edu

3.     Systematic Hospital-Based Travel Screening to Assess Exposure to Zika Virus, Aftab Iqbal et al.

Incidence of Zika virus infections rose rapidly in early 2015, and by March 2017 local transmission was confirmed in 84 countries and territories. Although the virus typically causes mild symptoms, infection in pregnant women can cause congenital Zika syndrome, resulting in devastating birth defects in newborn children. This threat of in utero infection, in addition to sexual transmission, led to public health advisories for women who were pregnant (or might become pregnant) and their partners to avoid travel to places where Zika virus was known to be transmitted. Starting in September 2015, Mount Auburn Hospital (Cambridge, Massachusetts, USA) began routinely asking all presenting patients about international travel in the past 30 days. After 12 months of data collection, researchers analyzed patient demographic information, travel destinations, and diagnoses for Zika virus exposure. Despite severe restrictions on testing for Zika virus infection at the time of the study, the researchers were able to identify patients with clinical findings that fit the case definition for Zika virus infection even when the patients were not tested. The analysis also identified a large proportion of patients who should have received Zika counseling before their travel. This type of analysis could eventually inform population-based programs for Zika virus vaccination. In addition, systematic travel screening could be applied by healthcare systems to other imported emerging infections in the future.

Contact: Lin H. Chen, Mount Auburn Hospital, email: lchen@hms.harvard.edu or Kelly Hill khill7@mah.harvard.edu



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