RESUMEN
Serological diagnosis of Zika virus is challenging due to high cross-reactivity of Zika virus with other flavivirus antibodies. Recently, a Zika NS1-based enzyme-linked immunosorbent assay (ELISA) was developed and shown to be highly specific for Zika antibody detection; however, sensitivity was evaluated for only a small number of confirmed Zika-infected patients. In this study, we measured the sensitivity and kinetics of Zika IgM and IgG antibodies using the Zika NS1-based ELISA in 105 samples from 63 returning travelers infected with Zika virus (proven by PCR or neutralization assay) from Israel, Czech Republic, Italy, Belgium, Germany, and Chile. Zika virus IgM was detected from 2 to 42 days post-symptom onset (PSO) with an overall sensitivity of 79% in the first month and 68% until 2 months PSO, while IgG antibodies were detected from 5 days to 3 years PSO with 79% sensitivity. Interestingly, significant differences in IgM sensitivity and IgM detection period were observed between Israeli and European/Chilean Zika-infected travelers, adding to the complexity of Zika infection diagnosis and suggesting that other diagnostic methods should be complemented to reduce false-negative results.
Asunto(s)
Anticuerpos Antivirales/sangre , Enfermedades Transmisibles Importadas/diagnóstico , Ensayo de Inmunoadsorción Enzimática/métodos , Pruebas Serológicas/métodos , Proteínas no Estructurales Virales/inmunología , Infección por el Virus Zika/diagnóstico , Adolescente , Adulto , Anciano , Formación de Anticuerpos , Niño , Preescolar , Chile , Europa (Continente) , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Factores de Tiempo , Viaje , Adulto JovenRESUMEN
BACKGROUND: Diagnosis of new emerging viruses in Israel is the responsibility of the Ministry of Health's Central Virology Laboratory (CVL). In April 2009, following the emergence of influenza H1N1 2009 virus in Mexico and the WHO declaration of pandemia, the Israeli preparedness plan was launched. AIMS: Development and application of a diagnostic test for H1N1 2009, diagnosis of cases in an outbreak setting and data analysis. METHODS AND RESULTS: In the absence of a validated test to detect the new strain of H1N1 2009, an RT-PCR amplification of a highly conserved matrix (M) gene of influenza A virus was employed. All positive PCR products were sequenced and compared to sequences in the GenBank. At a later stage, a specific kit provided by the WHO was used. Further improvements were introduced including "in-house" developed assays. Arrangements were made to allow around-the-clock testing of hundreds of samples without compromising other laboratory services. Between April 27th and mid July, 2809 samples were tested of which 1082 (38.5%) were positive. Most of the cases were found in the central part of Israel and around Jerusalem. The highest morbidity was in the 20-29 years age group, with the highest rate of positive cases in the 10-19 years age group. More males than females were ill. CONCLUSIONS: When a large outbreak of a novel infectious agent occurs, a supreme quality laboratory is essential. The Israel CVL made possible an early and prompt identification of H1N1 2009 from the outset and has met its ongoing challenges with a high degree of success.