Morbillivirus Prevalence among Marine and Terrestrial Carnivores from the Peninsula of Baja California, Mexico
Abstract
Morbilliviruses are infectious agents that belong to the Paramyxovirus family, including canine distemper virus, rinderpest, measles and other virus that infect different species of terrestrial mammals.2 Morbillivirus is also an emergent disease in the aquatic environment, distinguishing two different types that affect marine mammals: 1) Phocine Distemper Virus, that has been found in different species of pinnipeds around the world, causing massive epizootics within some populations mainly in Europe; 2) Cetacean Morbillivirus that has also been found to affect large populations of different species of dolphins in the Mediterranean Sea and in the Gulf of México, dividing these types into Porpoise Morbillivirus, Dolphin Morbillivirus and Pilot Whale Morbillivirus.3,4 In Mexico, morbillivirus has been reported in bottlenose dolphins, gray whales and sea lions, only causing massive mortality among the bottlenose dolphins. Morbillivirus transmission among marine mammals is considered to be density-dependent, signifying that the number of individuals in a population has a strong influence for morbillivirus to incur into an epizootic.5
In the present work we have chosen study sites among the Peninsula of Baja California that can enable the acquirement of biological samples for the diagnosis of morbillivirus from different species of marine mammals, and terrestrial carnivores that could be transmitting the virus to some colonies of sea lions distributed along the coasts of the Pacific Ocean and the Sea of Cortes. For this, we have managed to obtain blood, serum and swab samples from some domestic dogs and coyotes belonging to Isla Magdalena in Baja California Sur, as well as samples from sea lion pups belonging to the Gulf of California Islands. The samples have been stored with buffer RNAlater, maintaining a cold temperature until the arrival to the laboratory where they were stored at -80°C until the RNA extraction had been done, subsequently the samples were processed by RT-PCR for morbillivirus detection using primers that amplify a 429bp fraction of the viral phosphoprotein,1 and preparing the reaction with Qiagen one-step kit. Twenty-seven samples were processed by PCR, from which five turned out to be amplifying a 429bp fragment, three belonging to Sea lion pups from an island of the Gulf of California (Granito) and two from terrestrial carnivores, a coyote (Canis latrans) and a domestic dog (Canis familiaris), from Isla Magdalena in Baja California Sur, achievieng a prevalence of 18.5% for morbillivirus. For further investigation about this disease in marine mammals, sequencing the PCR products has been considered, as well as correlating the prevalence of the virus with the distribution, abundance and structure of the sea lion populations. Furthermore, phylogenetic studies are going to be carried out to compare the viral lineages of morbillivirus between the terrestrial carnivores and the sampled marine mammals.
Acknowledgements
The authors would like to thank the members from the CONANP of the Islands of the Gulf of California, México, owed to their support at field work, and the facilities they have given us. As well as the people from Baja California Sur that simplified field work at that region. Also the authors thank the people from the virology laboratory at the Faculty of Veterinary, UNAM, for providing a space and resources to carry on with the investigation.
* Presenting authors
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