Presented by: Kellie Lewis, Connie Driggers and Michelle Ruthenberg

 An epidemic that has swept over the marine environment is morbillivirus. The morbillivirus is a relatively new virus that primarily attacks the immune system of an organism. Once the virus has broken into the immune system, it moves into the lymph nodes and respiratory system. This virus has an outside coat of protein surrounding its negative sense, single stranded RNA. To spread, it fuses with the cell membrane allowing the viral genome to enter the cytoplasm. The morbillivirus then reproduces by budding and spreads throughout the body (Virology, 1998).

 The morbillivirus is from the family Paramyxovirdae. It itself is the genus. There are 7 different species of morbillivirus: canine distemper virus, dolphin distemper virus, measles virus, peste des petits ruminants virus, phocine distemper virus, porpoise distemper virus and rinderpest virus (Anderson, 1997).

 There are many symptoms of morbillivirus in organisms that have been infected. The first noticeable feature is usually a maculopapular rash, which is caused by an active immune response (Virology, 1998). Other symptoms include: fever, respiratory complications, intestinal inflammation, edematous (equation of watery fluids in connective tissues or serus cavity) lungs, nasal discharge, emphysema, edematous pulmonary lymph nodes, lymphocyte depletion and necrosis of neurons in the cerebral cortex. Once morbillivirus has reached the cerebral cortex, the animal will die. Disorientation is an indicator that the disease has gotten this far (Moeller, 1996).

 The morbillivirus is extremely contagious. It is usually spread via one's respiratory tract. There are a few testing techniques used for virus detection (Virology, 1998). All of them require the use of a serum sample. The serum sample is separated from the blood when it clots. This has the antibodies needed for testing. These samples are then analyzed by the use of two tests for detection of antibodies, Neutralization test and Elias test. Once these tests are completed their results are compared to the rinderpest antigen which is seen in cattle. If the antibodies correlate, then the organism is considered to contain the morbillivirus (Morse, 1993).

 One organism has been considered a vector for the virus since the infection seems to be enzootic in its population. It is the pilot whale. The pilot whale is an excellent vector since it mixes with at least 13 other cetacean species on a regular basis. Calves of this species have been seen to be immune to the disease because they have first been protected by maternal antibodies and later by constant contact with the disease, leading to immunity (Duke, 1997).

 In 1987 seals in Lake Baikal, Siberia were found to be infected with a strain of the morbillivirus. By 1988, 20,000 harbor seals, Phoca vitulina, in the North Sea had died due to this virus, which was later named phocine distemper virus (Webb, 1991). This outbreak coincided with a similar outbreak of distemper in dogs and some of the dead seals were found to be carrying antibodies to canine distemper, which was believed to have come from huskies.

 The infected seals were found to be suffering from respiratory distresses such as nasal discharge, and "upon necropsy there was severe pneumonia with evidence of bronchiolar damage and intracytoplasmic inclusions in bronchiolar cells" (Morse, 1993) as well as an abnormal accumulation of watery fluid in the lungs (Moeller, 1998). The central nervous system also showed signs of damage (Morse, 1993) and the brain experienced necrosis especially to the cerebral cortex (Moeller, 1998). All of these symptoms resemble those found in dogs with canine distemper (Morse, 1993).

 In 1988 another outbreak was discovered when 6 porpoises experiencing similar symptoms were found in the Irish Sea (Pain, 1998). It was thought that the seals in the North Sea caught the virus from the porpoises or vice versa, but that was never determined.

 This epidemic continued to spread among marine mammals and beginning in 1990 it was identified in striped dolphins, Stenella coeruleualba (Domingo et al, 1990).

 Between 1990 and 1992 more than 1,000 Mediterranean striped dolphins succumbed to an infection resembling the one that devastated the harbor seals in 1988. Symptoms included pulmonary and central nervous system lesions similar to those observed in the seals as well as pneumonia and enlargement of the lymph nodes (Moeller, 1998). In some individuals inflammation was also observed in the mammary glands. The brain also incurred some damage including "neuronal degeneration and necrosis" (Domingo et al, 1990). The virus even "destroyed white blood cells, making the animals more susceptible to other infections" as well (Pain, 1990).

 They tested many of the dolphins' organs and the morbillivirus antigen was found in lung, brain and lymph tissues "confirming that the isolated virus [was] a morbillivirus" (Domingo et al, 1990).

 In 1990 "more than 400 dead dolphins [were] found on beaches in Spain, France and Italy" and tests revealed that the dolphins were infected with the morbillivirus (Pain, 1990).

 Later, in 1991, the epidemic spread eastward where two more outbreaks were discovered. The first was off the coast of Italy and Sicily where 150 dead dolphins washed ashore and again when more strandings occurred on the coast of the Greek islands of Zankinthos (Webb, 1991).

 As this epidemic spread, scientists began to worry that "the virus could infect all types of marine mammals" (Pain, 1990). These fears were fueled further when, in 1995, the epidemic was found to have spread to another cetacean, the bottlenose dolphin, Tursiop trucatus (Epidemics, 1998). This time it was in the Gulf of Mexico where the morbillivirus killed hundreds of bottlenose dolphins.

 This spreading deepens the fear that this epidemic could "wipe out the worlds' last remaining monk seal population" in the Mediterranean because "the chances that monk seals [were] not susceptible [were] so slim as to be nonexistent" (Pain, 1990).

 In 1997 those fears rang true when a virus was identified in the organs of Mediterranean monk seals, Monachus monachus (Osterhaus et al, 1997). These seals are listed as an endangered species and about half of the population was killed by this outbreak in the Mediterranean. An autopsy on several of the individuals that washed ashore revealed that they were in a "state of advanced decomposition" and most of them suffered from respiratory distresses such as emphysema and congestion of the lungs. Upon testing it was shown that the virus these seals were infected with was in fact the morbillivirus and that it was closely related to the morbillivirus found in dolphins. Due to this recent mass mortality among Mediterranean monk seals this endangered species is even further under the threat of extinction. As of August 1997, "only about 600 Mediterranean monk seals remain in the wild, mostly in groups of about 20" (Raloff, 1997).

 Of course, Morbillivirus alone cannot be blamed for all the ocean's deaths. El Nino and water pollution are just two other problems that are affecting the oceans today. An epidemic is something that causes a large number of deaths within a species. Although El Nino and water pollution in themselves are not classified as an epidemic, they're effects can contribute to the likelihood of an epidemic.

 El Nino is characterized by the increased storm activities and the influx of warm water into the Eastern Pacific. The 1997 El Nino year was the strongest El Nino of the century. In South America an entire season of pup production by fur seals and sea lions had been wiped out. Most of the juvenile animals and a large part of the breeding adult population also apparently died. The animals that survived were weak and had decreased immune systems (Science News, 1996).

 In Peru, off the coast of South America, in 1997: 15 of several hundred fur seals were found alive. Only 1,500 of the original 8,00 sea lions survived. Dr. Majluf, a zoologist with the Wildlife Conservation Society was quoted as stating "The depleted wildlife population may not survive many more events of this magnitude." By having so many animals weakened by the effects of El Nino, it opened the door for viruses such as Morbillivirus to come in.

One other problem in the oceans is water pollution, and specifically high levels of PCB's. PCB's are industrial organochlorines that can suppress the infection fighting immune system. During 1994, in New York, 62% of Harbor seals found stranded off the coast not only had high levels of PCB's but also low counts of white blood cells that fight off infection (Science News, 1994). Again, with so many animals weakened by the effects of water pollution, it opens the door for other epidemics such as Morbillivirus to come in.

Our overall goal was to answer the question if we are able to control Mother Nature or will she just have her way? There is nothing we can do to stop the effects of El Nino weakening animals immune systems. By weakening immune systems it opens the door for such epidemics as the Morbillivirus. Although there is a vaccination for Morbillivius at this time it is just not possible to vaccinate every single animal. Over the years we have tried to control the amount of contaminants that enter the earth’s waters. There have been some improvements, but we have a long way to go before we can stop injuring the animals with water pollution. We came to the conclusion that Mother Nature is just too powerful and in the end she will have her way.  

Anderson, J. http://www.iah.bbsrc.ac.uk/virus/paramyxoviridae.haxon.htm. (1997).

Domingo, M., Ferrer, L., Marco, A., Plana, J., Kennedy, S., McAliskey, M. and Rima, B.K. Morbillivirus in Dolphins. Nature 348, 21 (1990). 

Duke. Http://duke.usaskca/~misra/virology/marine/Page1.htm. (1997).

Epidemics. Http://www.mcbi.org/epidemics.html. (1998).

Moeller, R. Http://www.afip.org/CLDavis/syllabi/mammals.txt. (1998).

Morse, S.S. 1993. Emerging Viruses. Oxford University Press, N.Y. pp. 184-191.

Osterhaus, A., Groen, J. and Niesters, H. Morbillivirus in monk seal mass mortality. Nature 388, 838-39 (1997).

Pain, S. Dolphin virus threatens last remaining monk seals. New Scientist 128, 22 (1990).

Raloff, J. Endangered seals suffer massive die-off. Science News 152, 134 (1997).

Virology. Http://www.uq.edu.au/vdu/morbillivi.htm. (1998).

Webb, J. Dolphin epidemic spreads to Greece. New Scientist 131, 18 (1991).

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