Please note, following publication of the original article , the authors have advised of three errors that are present in the published article. Firstly, the two instances of 'Albumax II' in the 'Methods' section of the article are incorrect: the reagent 'Albumax I' should be referred to instead. Secondly, 'giemsa' (also referred to in the 'Methods' section) should be capitalized, as 'Giemsa'. Finally, an incorrect version of Fig. 4 has been incorporated in the article; please find the correct version of Fig. 4 in this article, for reference. © 2020 The Author(s).