Trends in Parasitology, Volume 27, Issue 4, 155-159, 11 January 2011
Copyright © 2010 Elsevier Ltd All rights reserved.
Sand flies are the only accepted biological vectors of Leishmania parasites. However, secondary modes of transmission have been extensively discussed and speculated about in recent years. In particular, the hypothesis of ticks as vectors of Leishmania infantum was studied in the 20th century and today is being revisited using modern molecular biology techniques. Recent studies have shed new light on the discussion, but have also led to misleading conclusions on the role of ticks as Leishmania vectors. In this article, the role of brown dog ticks, Rhipicephalus sanguineus, as vectors of L. infantum is discussed, and the need for further research to better understand their participation in the epidemiology of leishmaniasis is advocated.
Xue-Jie Yu, M.D., Ph.D., Mi-Fang Liang, M.D., Shou-Yin Zhang, Ph.D., Yan Liu, M.D., Jian-Dong Li, Ph.D., Yu-Lan Sun, M.D., Lihong Zhang M.D., Quan-Fu Zhang, B.Sc., Vsevolod L. Popov, Ph.D., Chuan Li, B.Sc., Jing Qu, B.Sc., Qun Li, M.D., Yan-Ping Zhang, M.D., Rong Hai, M.D., Wei Wu, M.Sc., Qin Wang, Ph.D., Fa-Xian Zhan, Ph.D., Xian-Jun Wang, M.D., Biao Kan, Ph.D., Shi-Wen Wang, Ph.D., Kang-Lin Wan, Ph.D., Huai-Qi Jing, M.D., Jin-Xin Lu, M.D., Wen-Wu Yin, M.Ph., Hang Zhou, M.S, Xu-Hua Guan, Ph.D., Jia-Fa Liu, M.D., Zhen-Qiang Bi, Ph.D., Guo-Hua Liu, M.D., Jun Ren, M.D., Hua Wang, M.D., Zhuo Zhao, M.D., Jing-Dong Song, M.Sc., Jin-Rong He, B.Sc., Tao Wan, Ph.D., Jing-Shan Zhang, M.S., Xiu-Ping Fu, M.S., Li-Na Sun, Ph.D., Xiao-Ping Dong, Ph.D., Zi-Jian Feng, M.D., Wei-Zhong Yang, M.D., Tao Hong, M.D., Yu Zhang, M.D., David H. Walker, M.D., Yu Wang, M.D., Ph.D., and De-Xin Li, M.D.
March 16, 2011 (10.1056/NEJMoa1010095)
Heightened surveillance of acute febrile illness in China since 2009 has led to the identification of a severe fever with thrombocytopenia syndrome (SFTS) with an unknown cause. Infection with Anaplasma phagocytophilum has been suggested as a cause, but the pathogen has not been detected in most patients on laboratory testing.
We obtained blood samples from patients with the case definition of SFTS in six provinces in China. The blood samples were used to isolate the causal pathogen by inoculation of cell culture and for detection of viral RNA on polymerase-chain-reaction assay. The pathogen was characterized on electron microscopy and nucleic acid sequencing. We used enzyme-linked immunosorbent assay, indirect immunofluorescence assay, and neutralization testing to analyze the level of virus-specific antibody in patients’ serum samples.
We isolated a novel virus, designated SFTS bunyavirus, from patients who presented with fever, thrombocytopenia, leukocytopenia, and multiorgan dysfunction. RNA sequence analysis revealed that the virus was a newly identified member of the genus phlebovirus in the Bunyaviridae family. Electron-microscopical examination revealed virions with the morphologic characteristics of a bunyavirus. The presence of the virus was confirmed in 171 patients with SFTS from six provinces by detection of viral RNA, specific antibodies to the virus in blood, or both. Serologic assays showed a virus-specific immune response in all 35 pairs of serum samples collected from patients during the acute and convalescent phases of the illness.
A novel phlebovirus was identified in patients with a life-threatening illness associated with fever and thrombocytopenia in China. (Funded by the China Mega-Project for Infectious Diseases and others.)