(CNN) -- A beached whale in New Jersey has tested positive for a virus that likely caused more than 1,200 dolphins to become stranded in shallow water or to wash up on shores, researchers said Thursday.
After the 21-foot minke whale washed up on the shores of Atlantic City on May 1, a necropsy and subsequent analysis by the University of California, Davis confirmed that the whale was positive for cetacean morbillivirus, according to the Marine Mammal Stranding Center in Brigantine, New Jersey.
The virus is similar to measles in humans or canine distemper in dogs, according to the National Oceanic and Atmospheric Administration.
After consulting with disease experts and conducting tests on dolphins in several states, NOAA determined that morbillivirus is likely the cause for 1,283 dolphin "strandings" on the East Coast since last July. For each of the previous five years, there were an average of 253 strandings for that same time period.
The strandings, where dolphins get stuck in shallow water or wash up on shores, are more than five times the historical average in the affected areas: New York, New Jersey, Delaware, Maryland, Virginia, North Carolina, South Carolina, Georgia and Florida, according to NOAA.
Some of the stranded dolphins were found alive, but most were found dead, with many in a state of advanced decomposition. Many dolphins had lesions on their skin, mouth, joints, or lungs, according to data published on NOAA's website.
The minke whale, which was tagged with graffiti the night it washed up on the beach, is the first whale that tested positive for the virus in New Jersey. Some were found in other states along the East Coast.
"We've had three humpback whales that tested suspect positive, but we're still waiting for additional lab results. Two pigmy sperm whales have also tested positive," said Maggie Mooney-Seus, public affairs officer for NOAA.
Robert Schoelkopf, the director of the Marine Mammal Stranding Center, says it's unclear how the minke whale contracted the virus, but additional testing is being done.
"Minke whales don't travel in large groups like dolphins do, so it's still uncertain," Schoelkopf said.
Mooney-Seus said it was unknown whether "it's a strain of morbillivirus in whales or if it was transmitted from dolphins."
NOAA officials say there is no way to stop the spread of the virus. Currently, there are no medications or vaccines that could be effectively administered to wild marine populations.
"We can't inoculate every marine mammal in the ocean," Schoelkopf said.
Scientists hope that learning more about the virus will help them address factors that may facilitate its spread. While the virus is generally spread through the air or through contact with other animals, it is not infectious to humans.
On August 8, 2013, NOAA issued an Unusual Mortality Event in response to the high number of deaths. The declaration brought special federal attention to the deaths as something that serves as an indicator of ocean health and may give "insight into larger environmental issues which may also have implications for human health and welfare," according to NOAA's website.
The UME declaration for the mid-Atlantic bottlenose dolphins was one of 60 that the agency has issued since it was established under the Marine Mammal Protection Act in 1991.
In 29 of those cases, infections, biotoxins, human intervention and malnutrition, were among the causes determined.