August 2019

Emerging Infectious Diseases Journal

Highlights: Emerging Infectious Diseases, Vol. 25, No. 8, 2019

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 include a live link to the actual journal article in your stories. Once the embargo lifts, this month’s articles will be found in the Ahead of Print section of the EID website at

The articles of interest summarized below will appear in the August 2019 issue of Emerging Infectious Diseases, CDC’s monthly peer-reviewed public health journal. This issue will feature Emerging Viruses. The articles are embargoed until July 10, 2019, at 12 p.m. EDT.

1.      Lessons Learned from Dengue Surveillance and Research, Puerto Rico, 1899–2013, Tyler M. Sharp et al..

A historical review of more than 100 years of combating dengue fever in Puerto Rico reveals important lessons learned in the fight against this serious and sometimes deadly disease. Dengue is caused by one of four viruses spread through infective mosquito bites. There is no specific medicine to treat dengue other than iv fluids or widely available vaccine. Despite extensive efforts to prevent and control dengue, cases of illness and deaths continue to increase worldwide. To learn more about dengue on the island, investigators analyzed surveillance data from this U.S. territory affected by this disease for more than a century. The first cases of dengue in Puerto Rico were reported in 1899. The U.S. Public Health Service worked to combat the disease early on before the creation of the Centers for Disease Control and Prevention in 1946. In 1963, the Puerto Rico Department of Health requested assistance from the CDC to respond to a major dengue outbreak. Working together, over the years, epidemiologists and researchers at CDC, the Puerto Rico Department of Health, and other organizations developed new and better ways to test and track dengue infections in people, raise awareness among healthcare providers and the community, and control mosquitoes to limit spread of the virus. Their experiences show the value of close partnerships between academic, public, and private organizations, which will continue to be integral components of successful public health initiatives to combat dengue. The tools that have arisen from dengue surveillance and research in Puerto Rico are available to the global public health community and can be applied to other viruses spread by mosquitoes.

Contact: CDC Media Relations; phone: 404-639-3286 or email:

2.    Multistate Outbreak of Listeriosis Associated with Packaged Leafy Green Salads, United States and Canada, 2015–2016, Julie L. Self et al..

In the United States, listeriosis is an important foodborne disease, and outbreaks trigger public health investigations. In contrast to other foodborne bacteria, listeria can grow at refrigeration temperatures. In October 2015, PulseNet USA, a national network for tracking foodborne diseases, noted that bacteria isolated from listeriosis patients in 6 states were genetically closely related, and the Public Health Agency of Canada found that isolates from patients in that country were closely related to the US isolates.  A total of 19 cases in the United States and 14 cases and 3 deaths in Canada were identified. A collaborative US–Canada investigation, involving patient interviews, retail food sampling, environmental investigation, and laboratory data analysis identified that the source of the outbreak was packaged leafy green salads from a single processing facility in the United States. The product was subsequently recalled. Unique features that led to the success of this investigation were using whole-genome multilocus sequence typing to identify the close genetic relationships between the isolates; using single-interviewer, open-ended interviews to enable patients to mention consumption products (eg, green leafy salads) that might not have been on a closed-ended list; routine sampling and testing of retail products by state laboratories to associate the bacteria isolated from patients with those isolated from specific food products; and collaboration between US and Canada investigators to enable more timely and comprehensive withdrawal of the contaminated product from the market.

Contact: CDC Media Relations; phone: 404-639-3286 or email:

3.      Pseudomonas poae–Associated Fatal Septic Transfusion Reaction, Peoria, Illinois, USA, 2017, T.S. Woodring and J.J. Farrell

Transfusion-transmitted infections (TTIs) are caused by bacteria, viruses, parasites, or prions transmitted through blood product transfusions. In the United States, fatal TTIs from red blood cells are rare. Researchers at the University of Illinois College of Medicine in Peoria, Illinois, analyzed a fatal red blood cell transfusion for which standard 37°C cultures of the patient’s blood and the transfused blood product were negative, despite the fact that bacteria (later identified as Pseudomonas poae) were seen with a microscope in the blood product immediately after transfusion. Because cold storage of donated blood products prevents most harmful bacteria from reproducing and reaching life-threatening numbers, bacterial contaminants pose a minimal threat to the blood supply. However, non-pathogenic environmental bacteria such as P. poae, which are able to reproduce at cold storage temperatures even though they do not survive at the normal human body temperature of 37°C used in standard laboratory cultures, can trigger a fatal septic reaction in transfusion recipients without establishing infection in the recipient. The mechanism is likely due to dangerous levels of endotoxin (potent immune-stimulating molecules found within the bacterial cell membrane) or other bacterial antigens that provoke the dysregulated immune response of sepsis. In light of their findings, the researchers recommend that transfusion reaction workups of blood products include testing for organisms that can survive the low refrigeration temperatures used by blood banks to protect against bacterial contamination of blood products.

Contact: John Farrell, University of Illinois College of Medicine, Peoria, Illinois, 61603, USA; email:


Page last reviewed: August 22, 2019