Emergence of human babesiosis along the border of China with Myanmar: detection by PCR and confirmation by sequencing

Abstract

Babesiosis is a tick-borne, zoonotic disease caused by Babesia spp. Two cases of babesiosis were detected by nested polymerase chain reaction (PCR) in Yunnan province, China, and further confirmed by molecular assay. The blood smears showed intraerythrocytic ring form and tetrads typical of small B. microti. In both cases, the rapid diagnostic test (RDT) ruled out the possibility of co-infections with malaria. Neither case was initially diagnosed because of the low Babesia parasitemia. These two cases of babesiosis in areas along the Myanmar–China border pose the question of the emergence of this under recognized infection in countries or areas where malaria is endemic.

Figure 1 Microscopic evidence of babesiosis in a patient from the China–Myanmar border area. Giemsa stained thick blood smears (A) and thin blood smears (B and C) obtained on the first day of hospitalization for patient show an intraerythrocytic trophozoite (thin arrow). The lacking of hemozoin deposits distinguishes Babesia spp. from Plasmodium spp. The tetrad (thick arrow) is pathognomonic of small Babesia spp. Original magnification, ×1000.

• babesiosis
• malaria
• molecular assay
• Myanmar–China border areas

Xia Zhou conceived the study, collected the data and analyzed it, and drafted the manuscript. Sheng-Guo Li, Jia-Zhi Wang, Ji-lei Huang, He-Jun Zhou and Jun-Hu Chen revised the manuscript and provided interpretation of the findings, technical support for data collection and analysis. Xiao-Nong Zhou conceived the study and revised the manuscript. All authors read and approved the final manuscript. Written consent to publish was obtained. We would express our sincere gratitude to Professor Cally Roper from London School of Hygiene and Tropical Medicine for helping to review the manuscript and edit for the language. The research has been partially supported by the Special Fund for Health Research in the Public Interest China (NO 201202019), Strengthen Action Plan for Shanghai Public Health System Construction 2011–2013 (GW-11) and by the National Science & Technology Major Program (NO 2012ZX10004-220).