Scientists Identify Viruses Causing Lymphocystis in Fish

30 November 2016, at 12:00am

SPAIN - Lymphocystis is an infectious disease of fish which causes significant economic losses in aquaculture. A study, which involved the Autonomous University of Madrid, suggests a poliviral origin of the disease and provides the first identification of papillomaviruses in fish.

Farms in the European Union each year farm about 109,000 tons of gilthead sea bream (Sparus aurata), representing a turnover of more than 500 million euros annually. One of the main threats to the sector are viral infections, including lymphocystis.

This disease is characterised by the formation of tumors on the skin which is thought to be caused by infection with iridovirus.

Spanish researchers have used DNA techniques to study ultrasecuenciación community lymphocystis associated virus, which affects at least 150 different species of fish.

Through these techniques, scientists were able to assemble the complete genome of a new species of Iridoviruses, which turned out to be very different from two other genomes so far sequenced.

But in addition to describing this new species of Iridoviruses, LCDV-Sa, the team was able to identify a large number of sequences and SaPyV1 SaPV1 virus, belonging to the families papillomavirus and polyomavirus respectively.

"Joining these sequences we were able to complete the genome of papillomavirus first detected in fish, like the genome of one of the first polyomavirus found in these animals," said the scientists.

The finding of this first fish papillomaviruses, published in Journal of Virology , suggests that the evolutionary origin of this family is much older than previously thought, dating back about 500 million years. The SaPV1 papilloma virus also has a unique feature within the family: "His main capsid protein is expressed through a splicing mechanism known as RNA splicing," the authors explain.

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