Evaluation of a smartphone-based rapid fluorescent diagnostic system for H9N2 virus in specific-pathogen-free chickens.
Repeated interspecies transmission of H9N2 virus from poultry to humans and human infections transmitted via aerosols highlight the need for a highly sensitive, rapid diagnostic system for the detection of this virus. However, no such test exhibiting high performance has been developed. In this study, the performance of a smartphone-based rapid fluorescent diagnostic system (SRFDS) was optimized for the diagnosis of an H9N2-virus-infected animal. To suppress the nonspecific reactivity of the bioconjugate in oropharyngeal (OP) and cloacal (CL) samples derived from chickens, different blocking reagents were tested, and a mixture of casein and sucrose was found to be optimal. To assess the performance of SRFDS, OP and CL samples were obtained from specific-pathogen-free chickens and used for comparison of this method with real-time reverse transcription PCR (rRT-PCR) at time points of three, five, and seven days postinfection (dpi). The limit of detection of SRFDS was found to be 7.5 PFU/mL, which was 138-fold higher than that of a conventional colloidal-gold-based avian influenza rapid diagnostic test. In the animal study, the presence of viral antigen was monitored with SRFDS, and the relative sensitivity (relative to rRT-PCR results) was 94.44 % (17/18) and 95.23 % (20/21) in OP and CL specimens, respectively. The specificity of SRFDS was 100 %. These results imply that the diagnostic performance of SRFDS might be comparable to that of rRT-PCR for diagnosis of H9N2 in chickens and that this test can be used as a highly sensitive rapid diagnostic method in field studies on broiler poultry and wild birds.
Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, 570-749, Republic of Korea.
Seon-Ju
SJ
Yeo
Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, 570-749, Republic of Korea.
Bui Thi
BT
Cuc
College of Veterinary Medicine, Kangwon National University, Chuncheon, 200-701, Republic of Korea.
Haan Woo
HW
Sung
Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, 570-749, Republic of Korea. hyunpk@wku.ac.kr.
Hyun
H
Park
D000818:Animals; D000956:Antigens, Viral / Q000737:chemistry / Q000378:metabolism; D002645:Chickens; D003955:Diagnostic Tests, Routine / Q000295:instrumentation / Q000379:methods*; D005453:Fluorescence; D053127:Influenza A Virus, H9N2 Subtype / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D005585:Influenza in Birds / Q000175:diagnosis* / Q000821:virology; D011201:Poultry Diseases / Q000175:diagnosis* / Q000821:virology; D012680:Sensitivity and Specificity; D000068997:Smartphone / Q000706:statistics & numerical data*; D013047:Specific Pathogen-Free Organisms
D000956:Antigens, Viral