23 July 2020
This is part of a student blog series as part of the University of Pittsburgh’s Disease Ecology Class that our own Shane M Hanlon is currently teaching. Find out more about the series and read all the posts here!
By Rongwei Xai
This article focuses on reduction of sea ice extent in Arctic region which is caused by climate change might introduce many diseases that are locked in Arctic to sub-Arctic regions. The virus they track is called Phocine distemper disease (PDV), and it is a pathogen that majorly causes high rate of mortality in European harbor seals of northern Atlantic Ocean. PDV had never been an issue in Pacific Ocean seal species until 2004 when the PDV tested positive for Steller sea lions in northern Pacific Ocean. This discovery raises question that how does PDV reach the Pacific Ocean in 2004 and is it caused by reduction of Arctic ice extent.
There were 3 major PDV outbreaks: 1988 outbreaks 2002 outbreaks and 2006 outbreaks. The 3 outbreaks raise 2 questions about PDV.
The 1988 outbreak is very similar to 2006 outbreak, and researchers wonder if PDV contains multiple viral lineage that is circulating in Arctic and Atlantic seal species. In 2002 outbreak, researchers think if the virus is persisted in host for these years from 1988 to 2002 or if it is reintroduced. The major issue for these researchers to wonder is how does the virus reach the Pacific Ocean from Atlantic Ocean. They hypothesize that introduction of PDV from Atlantic to Pacific is linked with reduction in Arctic region caused by climate change.
Since seals species are hard to track, the major method that they use is collecting blood and nasal swab sample, and tissues from dead animals. They also use satellite image to see the change in ice extent.
Researchers find out that during summer time from August to September of year of 2002 and 2004, there are open water routes which connect the northern Atlantic and Pacific Ocean. According to the satellite image, there is a presence of an open water route along the Russia coast in August of 2002 which connect the Atlantic and Pacific Ocean. In 2006, there are also a small sample of sea lions which are tested positive for PDV in Gulf of Alaska of Pacific Ocean.
Connecting Atlantic and Pacific Ocean increase contact of marine mammals from these 2 areas, which lead to the increased possibility of PDV exposure to Pacific marine mammals.
From the timeline, 2002 PDV outbreak is consistent with the open water route along the Russian coast which lead to PDV transmission to Pacific region.This research result demonstrates that as climate changes, many viruses can transmit through long distance to infect species that have never been infect before. People should start to consider what can we do to minimize the climate change and issues like viral transmission.
This article is interesting because it helps me understand another effect from climate change, and it tells people that we should worry about climate change and its negative effects among animals.