Laboratory detection and molecular identification of a kala-azar case in Shenzhen
Objective To perform laboratory detection and molecular traceability analysis on a case of imported kala-azar in Shenzhen to determine the infection strain.Methods Bone marrow puncture fluid and blood samples from a case of kala-azar in Shenzhen were collected for laboratory tests.The patient's bone marrow puncture fluid smears were stained with Giemsa and examined under a microscope.Blood samples were examined for antibodies using the rk39 visceral leishmania rapid diagnostic reagent.Whole blood DNA was extracted,and the ITS-1 sequence was amplified by PCR,sequenced and aligned,and a phylogenetic tree was constructed based on the ITS-1 sequence.Results Microscopic examination of the patient's bone marrow smears revealed a large number of Leishmania amastigotes without flagella,confirming the diagnosis of kala-azar.The patient's blood was tested positive with the rk39 rapid diagnostic reagent,and PCR amplification yielded an ITS-1 gene product sequence that matched the expected size.Sequence alignment with the NCBI database showed 100％sequence similarity with the ITS-1 gene sequence of Leishmania infantum,confirming the infecting strain as Leishmania infantum.Phylogenetic tree construction of the amplified ITS-1 sequence revealed clustering into a clade with Leishmania infantum,and close to KC347299,one of the reference sequence selected.Conclusions The case of kala-azar in Shenzhen was caused by Leishmania infantum.Kala-azar still occurs in China,so the diagnostic technology of medical personnel in non-epidemic areas should be strengthened so that they can actively use new diagnostic technologies to assist in diagnosis,thus improving their prevention and control ability of Leishmania parasites.
NETL
NSTL
万方数据
