Estudo de casos suspeitos de dengue negativos no teste sorológico para detecção do antígeno NS1: falha no diagnóstico ou emergência de outras arboviroses?

Abstract

Dengue is currently considered the most important arbovirose. Its main vector is the mosquito Aedes aegypti, present in several regions around the world. The serological diagnosis by means of the NS1 antigen search is the one that has greater applicability, because of easy of execution and the window for detection between the 1st and the 9th day of the onset of symptoms, with a higher frequency until the 5th day. This study aimed to investigate the presence of dengue virus in samples with non-reactive results for the NS1 antigen, assessing if there was a failure in laboratorial diagnosis, or the existence of other arboviruses circulating in the state of Amazonas. Using the RT-qPCR technique, the presence of dengue virus was investigated in 306 serum samples from patients with clinical suspicion of infection. The samples that remained negative were investigated for the presence of the Zika (ZIKV), Chikungunya (CHIKV), Mayaro (MAYV) and Oropouche (OROV) viruses with the same methodology, as well as the presence of IgG and IgM for dengue virus by ELISA. Of the 306 analyzed samples, 17 (5.5%) were positive for DENV, with three sequenced for serotype 4. Thirty-four (10.8%) were positive for ZIKV, one (0.3%) for CHIKV, thirteen 4.2%) for MAYV and nine (2.9%) for OROV. In relation to the NS1 test, all kits evaluated presented 100% agreement in negativity. For the screening of anti-DENV antibodies of the IgG class, of the 306 samples tested 134 (43.8%) had positive results. Regarding the detection of the IgM antibody, different positivities were observed for commercial kits: VIRION (n = 250) 35.6% positive; FOCUS (n = 105) 10.5% positive and PANBIO (N = 80) 20% positive. Our results confirm cases of false negative results for the NS1 tests of three commercial kits, in addition to the circulation of other arboviruses among patients from different municipalities in the state of Amazonas.