FAQs on Morbillivirus and the Atlantic UME
Q: What is morbillivirus?
A: Morbilliviruses are in the family Paramyxoviridae. Specific morbilliviruses cause measles (in people), canine distemper (in dogs, coyotes, wolves, and seals), rinderpest (in cattle), and peste-des-petits-ruminants (goats and sheep). A morbillivirus has recently been associated with kidney disease in cats. Five types of morbilliviruses have been detected in marine mammals in the United States: canine distemper virus (CDV) and phocine distemper virus (PDV) in seals and sea otters, and dolphin morbillivirus (DMV) and pilot whale morbillivirus (PWMV), and Longman’s beaked whale morbillivirus (LBWMV), which are collectively referred to as cetacean morbillivirus (CMV) in porpoises, dolphins and whales.
Q: Is cetacean morbillivirus causing the mid-Atlantic Unusual Mortality Event?
A: Yes, based upon preliminary diagnostic testing and discussion with disease experts the tentative cause of this UME is being attributed to cetacean morbillivirus. However the investigation is still ongoing and additional contributory factors to the UME are under investigation including other pathogens, biotoxins, contaminants, range expansion, etc.
Q. How many dolphins have been affected during this Unusual Mortality Event?
A. We are posting updated numbers of affected dolphins and our findings during the investigation on the UME website each week. Currently dolphin morbillivirus positive bottlenose dolphins have been found in all states involved in the UME, with the mostly southerly stranded dolphin found in the Florida Keys in November 2014.
Q. What is the risk to humans from this virus?
A. To date, there are no reported cases of human infection with cetacean morbillivirus. Morbillviruses do not tend to infect hosts that are not closely related, and humans have their own morbillivirus, which is measles. More information on measles can be found can be found on the CDC website CDC website.
Q: What are the symptoms of morbillivirus in dolphins?
A: Cetacean morbillivirus affects the lungs, brain and immune system. In the dolphins that tested positive for this virus, many of them had skin, oral, and lung lesions, additionally some had presumptive secondary bacterial, fungal or parasitic infections.
Q: How long has cetacean morbillivirus been around?
A: Cetacean morbillivirus was first detected in the late 1980s/early 1990s in wild dolphin populations when disease outbreaks occurred in the mid-Atlantic and Mediterranean Sea.
Q: Has morbillivirus ever been detected in dolphins in the Mid-Atlantic before?
A: Yes, morbillivirus was detected in dolphins in the 1987-1988 bottlenose dolphin die-off. The 1987-1988 bottlenose dolphin mortality event occurred along the Atlantic Coast and spanned the region from New Jersey to Florida with over 700 dolphins stranding during that event (June 1987 to May 1988). All age classes were involved and dolphins showed similar lesions to the present UME. The cause of the 1987-88 event was determined to be morbillivirus infection (Lipscomb et al. 1994), however some animals also showed exposure to brevetoxin, a biotoxin associated with harmful algal blooms uncommon to dolphins in this region (Geraci 1989). The 1987-1988 event caused a 50% reduction in the coastal migratory bottlenose dolphin stocks leading to the stock being classified as “Depleted” under the Marine Mammal Protection Act.
Q: How does the virus spread among dolphins?
A: Morbilliviruses are usually spread through inhalation of respiratory particles or direct contact between animals, including between mothers and calves. Animals can also be exposed to the virus through other entryways such as the eyes, mouth, stomach, skin wounds, and the urogenital tract.
Q. Is there anything you can do to protect the dolphins?
A. Currently, there is no way to stop the spread of the virus in dolphin populations, and there are no vaccines or anti-viral medications currently available that could be administered to wild dolphin populations in an effective manner.
Q: What should I do to protect myself and my pets against this virus?
A: You should never approach or allow a pet to approach a live or dead marine mammal. Dolphins, like other marine mammals (whales, porpoises, seals and sea lions), are protected under the Marine Mammal Protection Act. Pets should be kept away from marine mammals. To our knowledge cetacean morbillivirus is not infective to pets but the dolphins may have other secondary bacterial or fungal pathogens. Dogs and cats can share infectious diseases with marine mammals and should not be allowed to approach live or dead ones, or to consume dead marine mammals or their parts. NOAA Fisheries recommends contacting your pet’s veterinarian to discuss the potential risk to pets in your local area. For more information, visit the CDC website.
Q: What guidance has been provided to the marine mammal stranding response teams regarding handling dolphins and potential human health impacts?
A: The Stranding Network normally follows safety precautions for handling stranded dolphins as provided in each organization's safety plans and NOAA Fisheries' "Best Practices for Marine Mammal Stranding Response, Rehabilitation, and Release."
Q: Is there a possible environmental (or anthropogenic) factor that triggers an outbreak like this, making dolphins more susceptible to infection?
A: We need further studies to determine if there are identifiable environmental or human-caused triggers for these outbreaks and whether these causes are reducing the population’s disease immunity or altering their resiliency to a significant disease outbreak. Changing environmental conditions may cause bottlenose dolphin populations that may not have been in contact before to have overlapping ranges now, introducing new diseases to both. Human introduced contaminants or human-caused injuries can also reduce the fitness of bottlenose dolphin populations by stressing their immune system or reducing genetic diversity.
Morbillivirus outbreaks may also be triggered by a drop in the immunity of bottlenose dolphin populations if they have not been exposed to the disease over time and natural immunity wanes.
Q: Does eating seafood pose a risk?
A: Cetacean morbilliviruses are not known to cause disease in fish or shellfish, and there are no documented cases of cetacean morbillivirus in fish or shellfish.
Updated: January 8, 2015