Protein in louse intestine ‘offers potential for fish vaccine’

University of Bergen PhD candidate Erna Irene Heggland will defend her thesis Haematophagy in the salmon louse (Lepeophtheirus salmonis): characterisation of genes and proteins involved in parasite blood-feeding on Thursday.

Having blood as part of the diet is a common phenomenon among parasites, as blood is both nutritious and a renewable source in the host animal. In this way, the parasite can live off its host without necessarily killing it. 

Weaknesses in lice

Blood contains large quantities of iron and haem molecules (a ferrous substance from another haemoglobin) that are potentially particularly toxic if not handled properly.

Haematic parasites, including salmon lice, therefore need strictly controlled ways to absorb and store the iron in their bodies. Researching this can reveal weaknesses in the lice that can be exploited in vaccine development.

The purpose of the doctorate is to investigate the genes and proteins that are important for the louse when it takes blood, and especially when handling iron and haem. Through her work, Heggland, among others, has investigated the storage of iron and the absorption of haem from the gut by salmon lice.

Egg production

Heggland has found that if one inhibits the salmon louse’s ability to store iron or absorb haem, it has major negative consequences for egg production in adult lice. Thus, there are fewer lice in the next generation to infect fish. Furthermore, she has investigated when in its life cycle that the louse starts consuming blood, and what consequences it has for the louse.

The work on this doctoral degree has resulted in new general knowledge about the biology of salmon lice, but it has also resulted in discoveries of protein in the louse’s gut that can potentially be attacked by a vaccine.