Studies on the Middle East Respiratory Coronavirus in dromedary camels in Ethiopia

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H04642
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 海外学術
• Research Field: Veterinary medical science
• Research Institution: National Institute of Infectious Diseases
• Principal Investigator: Shirato Kazuya 国立感染症研究所, ウイルス第三部, 主任研究官 (40415477)
• Co-Investigator(Kenkyū-buntansha): 泉對 博 日本大学, 生物資源科学部, 教授 (10355167)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: MERS / MERS-CoV / ヒトコブラクダ / エチオピア

Outline of Final Research Achievements

MERS-CoV is common in dromedaries throughout the Middle East, North Africa, and East Africa as evidenced by neutralizing antibodies against MERS-CoV; however, human cases have remained limited to the Middle East. To study the cause of this difference, the virological properties of African camel MERS-CoV were analyzed based on the spike (S) protein in Ethiopia. Nasal swabs were collected from 258 young dromedaries in the Afar region, of which 39 were positive for MERS-CoV, as confirmed by genetic tests. Recombinant EMC isolates of MERS-CoV, in which the S protein is replaced with those of Amibara isolates, were generated. Amibara S recombinants replicated more slowly in cultured cells than in EMC S recombinants. In neutralizing assays, Amibara S recombinants were neutralized by lower concentrations of sera from both Ethiopian dromedaries and EMC isolate-immunized mouse sera. These results suggest that these differences may account for the absence of human MERS-CoV cases in Ethiopia.

Free Research Field

ウイルス学

Academic Significance and Societal Importance of the Research Achievements

MERSの発症例が中東に限定され、アフリカから報告されていない原因は公衆衛生状態の差、検査体制の差など社会的な差であると考えられていた。今回の報告でそれぞれの地域で存在しているウイルスのウイルス学的特徴が違うことも、ヒトで報告がない原因である可能性が示唆された。