March 2022

Emerging Infectious Diseases Journal

Highlights: Emerging Infectious Diseases, Vol. 28, No. 3, March 2022

The articles of interest summarized below will appear in the March 2022 issue of Emerging Infectious Diseases, CDC’s monthly peer-reviewed public health journal. This issue will feature mycobacterial infections. The articles are embargoed until February 16, 2022, at noon Eastern time.

Important Note: Most articles that EID publishes do not represent work done at CDC or by CDC staff. In your stories, please use our suggested language to clarify whether a study was conducted by CDC (“a CDC study”) or by another institution (“a study published by ____ 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.

Please link directly to the actual journal article in your stories. Once the embargo lifts, this month’s articles will be found in the Early Release section of the EID website.

EID is publishing many articles on the COVID-19 pandemic. Because we publish those articles on an expedited track, and we have no embargo on their content, we do not include them in these monthly press notices. You may wish to subscribe to receive email notifications when EID publishes expedited articles as well as other types of articles.

Note that the most recent EID COVID-19 papers are at the top of the journal’s home page and also included in the Coronavirus Spotlight.

  1. Rising Incidence of Legionnaires’ Disease and Associated Epidemiologic Patterns, United States, 1992–2018, Albert E. Barskey et al.Legionnaires’ disease is a severe pneumonia caused by Legionella bacteria. Legionella exist in most freshwater environments in low numbers, but the bacteria can proliferate in humanmade environments, particularly when the water is warm, stagnant, and lacking residual disinfectant. Legionnaires’ disease can be acquired when aerosolized water containing Legionella bacteria is inhaled, and some devices, such as cooling towers, hot tubs, showers, and decorative fountains, can aerosolize water and have frequently been associated with outbreaks. Reported cases began increasing in the United States in 2003, but the causes of the rise are unclear. Researchers compared epidemiologic patterns associated with cases reported to CDC before and during the rise. The age-standardized average incidence was 0.48 cases/100,000 population during 1992–2002 compared with 2.71 cases/100,000 in 2018. This rise was most strikingly associated with wider racial disparities, intensifying geographic focus, and more pronounced seasonality. Reported incidence of Legionnaires’ disease increased in nearly every demographic group but increases tended to be larger in demographic groups with higher incidence (e.g., Black or African American persons). Incidence and increases in incidence were generally largest in the East North Central, Middle Atlantic, and New England divisions. Seasonality was more pronounced during 2003–2018, especially in the Northeast and Midwest. A properly designed and implemented water management program can reduce the risk for Legionella growth and transmission in buildings with complex water systems. However, nearly 64% of reported cases have no known potential exposure and generally lack an identified source, so improved investigations of sporadic cases and their sources may lead to novel prevention strategies and identification of previously unrecognized outbreaks.Contact: CDC Media Relations, phone: 404-639-3286 or email:
  2. Plasmodium falciparum pfhrp2 and pfhrp3 Gene Deletions from Persons with Symptomatic Malaria Infection in Ethiopia, Kenya, Madagascar, and Rwanda, Eric Rogier, et al.In 2019, more than 90% of the 409,000 people who died of malaria were in sub-Saharan Africa (SSA). Most symptomatic malaria infections in SSA are caused by the blood parasite Plasmodium falciparum. Rapid diagnostic testing for malaria involves detecting an antigen produced exclusively by P. falciparum parasites: histidine-rich protein 2 (HRP2). The ability to detect this antigen (and a truncated paralog, HRP3) has revolutionized the diagnosis of malaria throughout SSA, and other P. falciparum-endemic settings. However, in many areas of the world, including SSA, P. falciparum variants have been identified which have the pfhrp2 gene deleted, with some also deleting the pfhrp3 gene. Absence of the HRP2 and HRP3 antigens in P. falciparum parasites can lead to false-negative rapid test results. To determine the extent of these gene deletions, researchers genetically tested samples that were routinely collected to check effectiveness of anti-malarial therapy. They found low levels of gene deletions in P. falciparum from Ethiopia, Madagascar, Kenya, and Rwanda, and provided data for some sites which had never been sampled from before. Screening previously collected samples from malaria patients for pfhrp2 and pfhrp3 deletions provided useful information for evaluating where these genotypes exist and supports the continued use of rapid testing using HRP2-based tests in the areas studied.Contact: CDC Media Relations, phone: 404-639-3286 or email:
  3. Overseas Treatment of Latent Tuberculosis Infection in US–Bound Immigrants, Amera Khan et al.Nearly 70% of tuberculosis (TB) cases in the United States occur among non–U.S.-born persons. Cases usually result from reactivation of latent TB infection (LTBI) likely acquired before the person’s arrival in the United States. Researchers conducted a study among U.S. immigrant visa applicants undergoing the required overseas medical examination in Vietnam. Vietnam is in the top 5 countries of birth for non–U.S.-born persons with TB in the United States. Consenting applicants >15 years of age were offered a laboratory test to detect Mycobacterium tuberculosis, the causative agent of TB disease. Eligible participants were offered LTBI treatment with 12 doses of weekly isoniazid and rifapentine. Of 5,311 immigrant visa applicants recruited, 2,438 (46%) consented to participate; 2,276 had a laboratory TB test processed, and 484 (21%) tested positive. Among 452 participants eligible for treatment, 304 (67%) initiated treatment, and 268 (88%) completed treatment. The findings demonstrate that using the overseas medical examination to provide voluntary LTBI testing and treatment should be considered to advance U.S. TB elimination efforts.Contact: Amera Khan, Stop TB Partnership, Geneva, Switzerland; email:


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