Hantaviruses belong to the genus Hantavirus of the family Bunyaviridae. Hantavirus virions contain three segmented negative-sense RNAs designated S, M, L that encode a nucleocapsid (N) protein, enveloped glycoproteins (Gn and Gc), and an RNA-dependent RNA polymerase (L protein), respectively . Viruses in the genus Hantavirus contain causative agents of two important rodent-borne febrile zoonoses, hemorrhagic fever with renal syndrome (HFRS) in the Old World and hantavirus pulmonary syndrome (HPS) in the New World .
So far, 24 virus species that represent serotypes and genotypes have been registered within the genus Hantavirus by the International Committee on Taxonomy of Viruses . Four of those virus species, Hantaan virus (HTNV), Seoul virus (SEOV), Dobrava-Belgrade virus (DOBV), and Puumala virus (PUUV), are known to cause HFRS. The milder type of HFRS in Northern Europe, caused by PUUV infection, was historically called nephropathia epidemica (NE). Sin Nombre virus (SNV), Andes virus (ANDV), Laguna Negra virus (LANV), and many other related viruses are known as causative agents of HPS . There is a close association between the virus species and their rodent hosts, probably due to the co-evolution of rodent hosts and viruses for many thousands of years . As a consequence, endemic areas of HFRS and HPS depend on the rodent habitat. However, imported cases of HFRS and HPS between different countries and continents have been reported [6–8]. Furthermore, more than one hantavirus species is present in some regions, and the severity of disease differs depending on the virus . In addition, clinical diagnoses of HFRS and HPS patients are not effective in some cases as they represent mixed-syndrome between HFRS and HPS [10, 11]. Therefore, screening and typing of hantavirus infections provides important epidemiologic information.
Hantaviruses can be divided into antigenically distinguished species by neutralization tests, which show the antigenic differences of Gn and/or Gc proteins. While, it has been reported that hantavirus species can be divided into three antigenic groups based on antigenic cross-reactivity mainly at the N terminal end of N protein: group I (HTNV, SEOV, and DOBV, which are derived from Murinae rodents), group II (PUUV, and nonpathogenic vole-borne hantaviruses, Tula virus, Prospect Hill virus, and others, those are derived from Microtinae rodents) and group III (SNV, ANDV and related New World hantaviruses derived from Sigmodontinae and Neotominae rodents) . Therefore, three kinds of antigens from each of the three antigenic groups I, II, and III are necessary for screening of all of the rodent-borne hantavirus infections.
We previously developed an Escherichia coli (E. coli) and baculovirus-expressed recombinant N protein for screening and serotyping patient samples in an enzyme-linked immunoassay (ELISA) for HFRS and HPS viruses [12, 13]. Herein, we describe a pilot study to assess a new rapid immunochromatography (ICG) test with recombinant antigens using E. coli-expressed common antigenic sites located in the N terminal end of N protein for detection of specific IgG antibodies in acute and convalescent samples of patients with clinical infection caused by various hantavirus species. In addition, the ICG test was evaluated for the ability to discriminate among the three main hantavirus groups.