The CDC Epidemic Intelligence Service Provides Updated Research on Emerging Infectious Diseases at Recent Conference

“An outbreak anywhere is a risk everywhere,” according to the Centers for Disease Control and Prevention (CDC). Officers of the CDC’s Epidemic Intelligence Service (EIS) are studying several emerging infections — those that have recently increased or show signs of increasing soon – and five researchers presented their results May 4 in the Emerging Infections session of the 65th Annual Epidemic Intelligence Service (EIS) Conference in Atlanta, Georgia. A summary of these presentations is included below:

Large mosquito-borne Zika virus (ZIKV) outbreaks have recently occurred in Southeast Asia, Pacific Ocean islands, and Central and South America, and the virus will likely continue to spread to other areas, including the United States, according to Morgan J. Hennessey, DVM, MPH, and colleagues.

Travelers to areas with active ZIKV need to learn their risks and the ways they can avoid exposure to mosquitoes. And healthcare providers and public health officials need to understand the risks, know how to prevent transmission, and be able to recognize the disease in returning travelers.

In their review of the epidemiology and clinical features of travel-associated ZIKV disease cases in the United States, the authors identified all positive ZIKV test results performed at the CDC from 2010 through 2014 and collected information on demographics, clinical features, and travel history. They identified 11 (6 male) travel-associated ZIKV disease cases in the United States in patients ranging in age from 20 to 74; 9 of them became ill between January and April 2014.

Overall, 10 patients reported rash, 9 reported fever, 8 myalgia, 7 arthralgia, and 5 conjunctivitis. All of the travelers reported having visited islands in the Pacific Ocean days before they became ill and all of them had the potential to spread ZIKV in the United States after their return, the authors cautioned.

In another study, Dr. Hennessey and his co-authors surveyed people in the US Virgin Islands to gauge the likelihood of their accepting a Chikungunya virus (CHIKV) vaccine, several of which are being developed, and they found that educating people about vaccine safety would likely improve its acceptability.

The authors administered a questionnaire to all residents of randomly selected households. Responders who were interested in being vaccinated were similar in age (median 50 years) to those not interested (median 55 years); sex (56% female in both groups); whether or not they had had recent symptoms (38% of those interested in a vaccine and 35% of those uninterested); and whether or not they used insect repellant (31% of those interested and 38% of those uninterested). Overall, 52% of uninterested responders cited safety concerns.

Yuri P. Springer, PhD, and his research team identified a novel species of Orthopoxvirus in an Alaska resident who had not recently traveled outside the state, and they advise healthcare professionals to test patients who have poxvirus-infection-like illness for Orthopoxvirus.

In September 2015, the Alaska Division of Public Health investigated a report of a patient living in the interior Alaska woods who was sick with an Orthopoxvirus-like infection. The investigators interviewed the patient and cultured swabs from a papulovesicular back lesion, sequenced DNA fragments by quantitative real-time polymerase chain reaction (qPCR) and compared them with fragments from known Orthopoxviruses. They tested sera from the patient and contacts for Orthopoxvirus antibodies; they swabbed household surfaces, clothing and personal effects; and they tested small mammal feces by qPCR.

The patient had not recently traveled outside Alaska, and the qPCR confirmed a novel Orthopoxvirus species. Consistent with recent Orthopoxvirus infection, the patient’s serum was positive for IgM and IgG. Sera from all 4 contacts were IgM-negative, and sera from 2 contacts who had been vaccinated for smallpox were IgG-positive. Wild rodents lived outside the home and occasionally entered it, but none of the 23 environmental samples tested positive and no additional human cases were identified.

In Guinea, where community members and health facilities report all deaths and affected Ebola cases to either a local telephone alerts system at prefecture health offices or to a national toll-free call center established in November 2014, Christopher T. Lee, MD, and his group found that the local system worked better than the national call center to detect new Ebola cases.

The authors linked the 8,667 alerts from the passive surveillance databases of the four prefectures that had Ebola cases from April 2015 through August 2015 with the 9,454 records from the viral hemorrhagic fever (VHF) database. To determine sensitivity, they calculated the proportion of confirmed cases in the VHF database with a match found in each passive surveillance database.

Overall, 221 confirmed cases of Ebola were reported in the VHF database. Linking the two surveillance databases with the VHF database identified 5,006 matches, of which 120 were confirmed cases. Of these, 113 cases originated locally (sensitivity 51.1%; positive predictive value [PPV] 1.6%); 7 originated from the national call center (sensitivity 3.2%; PPV 0.4%); and the rest were detected through contact tracing or Ebola treatment units. In all four prefectures, the local alerts had higher sensitivity than the national call center.

Acute flaccid myelitis (AFM) may be associated with enterovirus-D68 (EV-D68), according to results by Negar Aliabadi, MD, and her colleagues, who found that EV-D68 detection in AFM cases significantly exceeded detection in controls, supporting a possible association between them.

Between August and October 2014, around the time of a nationwide outbreak of EV-D68 respiratory disease, doctors were puzzled to also see AFM in more children, whose cerebrospinal fluid results did not reveal a cause.

Colorado had the most AFM cases in the country, and the researchers studied children under 18 years of age hospitalized in the Denver area with acute focal limb weakness and gray matter spinal cord lesions of unknown cause on MRI. As controls, they used children with nasopharyngeal specimens collected during the same time period at outpatient visits for respiratory viruses (RV) or Bordetella pertussis (BP) in the same setting.

Overall, 10 of 11 (91%) cases had respiratory symptoms, vs 96 of 123 (80%, p=0.69) of RV controls and 263 of 274 (98%, p=0.25) of BP controls, and the cases were older than the RV controls (8 vs 5 years, median, p=0.04). EV-D68 was found in 4 of 11 (36%) AFM cases vs in 6 of 123 (5%) RV controls (p<0.01) and in 31 of 274 (11%) BP controls (p<0.01). The AFM cases had higher risk of EV-D68 detection compared with the RV controls (odds ratio 10.6, 95% CI, 1.9 to 66.7) and BP controls (odds ratio 5.5, 95% CI, 1.2 to 25.7), but AFM and non-EV-D68 enterovirus were not associated.

Lorraine L. Janeczko, MPH, is a medical science writer who creates news, continuing medical education and feature content in a wide range of specialties for clinicians, researchers and other readers. She has completed a Master of Public Health degree through the Department of Epidemiology of the Johns Hopkins Bloomberg School of Public Health and a Dana Postdoctoral Fellowship in Preventive Public Health Ophthalmology from the Wilmer Eye Institute, the Johns Hopkins University School of Medicine and the Bloomberg School.

SOURCE: EIS 2016 Conference Program, pp 83-85: Concurrent Session J1: Emerging Infections

Studies Presented:

Morgan J. Hennessey, DVM, MPH, EIS officer, Division of Vector-Borne Diseases, Zika Virus in Returning U.S. Travelers — United States 2010—2014

Morgan J. Hennessey, DVM, MPH, EIS officer, Division of Vector-Borne Diseases, Acceptability of a Chikungunya Virus Vaccine — United States Virgin Islands, 2015

Yuri P. Springer, PhD, EIS officer, Division of Scientific Education and Professional Development , Epidemiology Workforce Branch, Alaska Resident Infected with a Novel Species of Orthopoxvirus — Alaska, 2015

Christopher T. Lee, MD, EIS officer, Division of Scientific Education and Professional Development , Epidemiology Workforce Branch, presented CDC Ebola Response Team Comparison of Sensitivity of a National Call Center with a Local Alerts System for Detection of New Cases of Ebola — Guinea, 2014—2015

Negar Aliabadi, MD, EIS officer, National Center for Immunization and Respiratory Diseases, Enterovirus-D68 and Acute Flaccid Myelitis Among Children: A Case-Control Study in Colorado, 2014