## 4 Discussion
Furthermore, in instances where original samples yield very low PCR-positive results, isolation provides a means for generating enough RNA for whole genome sequencing. This in turn provides valuable information for use in epidemiology as well as virological/phylogenetic investigations. Currently four genotypes of MVEV are recognized, however full genome sequencing has only been performed on five isolates, four of which are from at least 40 years ago [1]. Thus, information on today's portrait of circulating MVEV and how this pertains to clinical outcomes is limited. A recent study by [PERSON] et al., 2015 described the sequencing of smaller gene fragments including pre-membrane and envelope genes from 66 strains of MVEV from 1951 to 2011 [5]. The paper confirmed that Genotype 1 is the predominant genotype in Australia and revealed that more recent strains of MVEV belong to 2 distinct sub-lineages of Genotype 1: G1A and G1B, of which G1B is more geographically diverse and most widely transmitted, leading to suggestions that it may have a replicative advantage. In light of this data, as well as previous findings by [PERSON] et al., 2015 [5] where all Genotype 2 strains originated from mosquito isolates in the north east Kimberly region of Western Australia, our identification of Genotype 2 in recent, human derived MVEV from the Northern Territory is somewhat surprising. The current profile of MVEV Genotype 2 describes a less dominant species. Suggested to be initially introduced from Papua New Guinea, Genotype 2 has either become more established over time, or been repeatedly re-introduced. The geographically confined nature of Genotype 2 has led to suggestions that it inhabits an ecological niche, [5] while mouse models demonstrate it to be phenotypically less virulent compared to the dominant MVEV Genotype 1 [13]. Additionally, it has been demonstrated that time, rather than geographical location, is the main predictor for all circulating MVEV genotypes, (i.e., all strains over a geological range at a single time point are related [14]). Thus, while the low numbers of clinical MVEV cases makes it difficult to draw definitive conclusions regarding the significance of this case the following questions arise: Does the appearance of MVEV Genotype 2 causing human disease reflect a single 'rare' incidence or importation; or is Genotype 2 becoming a more dominant representative of MVEV currently circulating? Considering the high proportion of MVEV infections that remain asymptomatic it is realistic to suggest that this single case could represent just one out of hundreds of undetected infections. Furthermore, the detection in humans may mean that this current Genotype 2 is more virulent than previously believed. Whether this virulence is due to genetic evolution of local MVEV or the result of an import is yet to be determined. The following are available online at [[http://www.mdpi.com/1999-4915/10/6/319/s1](http://www.mdpi.com/1999-4915/10/6/319/s1)]([http://www.mdpi.com/1999-4915/10/6/319/s1](http://www.mdpi.com/1999-4915/10/6/319/s1)), Figure S1: Genomic Analysis of VIDRL-MVE. **Author Contributions:** [PERSON], [PERSON], [PERSON] and [PERSON] were involved in planning, writing and preparing the manuscript. [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] were involved in NGS, SNP and phylogenetic analysis. [PERSON] and [PERSON] were responsible for patient care, management and supply of CSF. [PERSON] was involved in isolation of MVEV.