Pre-weaning diarrhoea, has been a problem in mink farms for many years. The "greasy kits" syndrome is a condition of newborn mink characterised by diarrhoea accompanied by skin swelling and redness, skin exudates and blackness of the nails. The present invention relates to polynucleotides and polypeptides of the capsid protein of a novel mink astrovirus strain denoted DK7627. Such polynucleotides and polypeptides may be used for the production of vaccines against mink astrovirus which may induce pre-weaning diarrhoea in minks. The invention furthermore relates to vectors, host cells, compositions and detection methods.