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New tickborne virus emerges in China

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Don’t discount population surveillance

New technology and genomic surveys will continue to help identify emerging pathogens, however, “they may provide limited value in understanding the mechanisms of disease emergence,” wrote Nikos Vasilakis, PhD, and David H. Walker, MD, in an accompanying editorial. An active surveillance program allowed the investigators of the previously unknown tickborne pathogen in China to identify a group of patients with similar history. The new pathogen was classified as one of the jingmenviruses, which “reveal that RNA virus segmentation is an evolutionary process that has occurred in previously unanticipated circumstances.” This study by Wang et al. shows that these viruses are not limited to arthropod hosts but can be dangerous to humans.

The new pathogen had likely been evolving for some time before it was discovered, the editorialists said. “The key to making such discoveries is the study of ill persons, isolation of the etiologic agent, use of tools that will reveal the nature of the agent (e.g., electron microscopy), and application of the appropriate tools for definitive characterization (e.g., sequencing of the RNA genome),” they emphasized. However, to mitigate outbreaks, “proactive, real-time surveillance” may be more cost effective than extensive genomic surveys, they noted (N Engl J Med. 2019 May 29. doi: 10.1056/NEJMe1901212).

Dr. Vasilakis and Dr. Walker are affiliated with the department of pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, and the Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston. They had no financial conflicts to disclose.



A new virus has been associated with febrile illness in China in patients with histories of tick bites. The data on the discovery, isolation, and characterization of the virus were reported in the New England Journal of Medicine.

The segmented RNA virus now known as Alongshan virus (ALSV) “belongs to the unclassified jingmenvirus group in the family Flaviviridae, which includes the genera flavivirus, pestivirus, hepacivirus, and pegivirus,” wrote Ze-Dong Wang, PhD, of Foshan (China) University, and colleagues.

The index patient with ALSV was a 42-year-old female farmer from the town of Alongshan, China, who presented to a regional hospital in April 2017 with fever, headache, and a history of tick bites. The initial clinical features were similar to those seen in tickborne diseases, but a blood sample showed no RNA or antibodies for tickborne encephalitis virus. Investigators obtained a blood specimen from the index patient 4 days after the onset of illness. After culturing the sample, the investigators extracted the viral RNA genome and sequenced it.

Sequence analysis found that the new pathogen was related to segmented viruses in the jingmenvirus group of the family Flaviviridae; however, “comparison of the amino acids further confirmed that ALSV is genetically distinct from other jingmenviruses,” the investigators said.

The investigators identified 374 patients who presented to the hospital with fever, headache, and a history of tick bites during May 2017–September 2017; 86 patients had confirmed ALSV infections via nested reverse-transcription polymerase chain reaction testing. Of these, 63 were men and 84 were farmers or forestry workers. Although ticks were common in the patients’ environments, no other evidence of tickborne diseases was noted. The patients ranged in age from 24 to 77 years, and the average duration of the infection was 3-7 days.

Symptoms were nonspecific and included fever, headache, fatigue, nausea, cough, and sore throat. All 86 patients were treated with intravenous ribavirin (0.5 g/day), and intramuscular benzylpenicillin sodium (2 million U/day) for 3-5 days. The median hospital stay was 11 days, and no deaths or long-term clinical complications occurred in the confirmed ALSV patients.

ALSV is similar to other jingmenviruses, but is distinct from other infections in part because of the absence of a rash or jaundice, the investigators said.

Although the investigators said they suspected the disease was carried by ticks, they would not rule out mosquitoes as a possible carrier because ALSV RNA was found in mosquitoes in a Northeastern province of China, and the RNA from those mosquitoes was found to be genetically related to the RNA assessed in this study.

Overall, “our findings suggest that ALSV may be the cause of a previously unknown febrile disease, and more studies should be conducted to determine the geographic distribution of this disease outside its current areas of identification,” they said.

The research was supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China.

SOURCE: Wang Z et al. N Engl J Med. 2019 May 29. doi: 10.1056/NEJMoa1805068.

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