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Novel adenovirus detected in captive bottlenose dolphins (Tursiops truncatus) suffering from self-limiting gastroenteritis.

Rubio-Guerri C, García-Párraga D, Nieto-Pelegrín E, Melero M, Álvaro T, Valls M, Crespo JL, Sánchez-Vizcaíno JM - BMC Vet. Res. (2015)

Bottom Line: In marine mammals, adenovirus has been associated with fatal hepatitis in sea lions.This adenoviral infection can be detected by serology and by PCR detection in fecal material.Our findings suggest the need for vigilance against adenoviruses in captive and wild dolphin populations.

View Article: PubMed Central - PubMed

Affiliation: VISAVET Center and Animal Health Department, Veterinary School, Complutense University of Madrid, Av Puerta del Hierro s/n, 28040, Madrid, Spain. consuelo@sanidadanimal.info.

ABSTRACT

Background: Adenoviruses are common pathogens in vertebrates, including humans. In marine mammals, adenovirus has been associated with fatal hepatitis in sea lions. However, only in rare cases have adenoviruses been detected in cetaceans, where no clear correlation was found between presence of the virus and disease status.

Case presentation: A novel adenovirus was identified in four captive bottlenose dolphins with self-limiting gastroenteritis. Viral detection and identification were achieved by: PCR-amplification from fecal samples; sequencing of partial adenovirus polymerase (pol) and hexon genes; producing the virus in HeLa cells, with PCR and immunofluorescence detection, and with sequencing of the amplified pol and hexon gene fragments. A causative role of this adenovirus for gastroenteritis was suggested by: 1) we failed to identify other potential etiological agents; 2) the exclusive detection of this novel adenovirus and of seropositivity for canine adenoviruses 1 and 2 in the four sick dolphins, but not in 10 healthy individuals of the same captive population; and 3) the virus disappeared from feces after clinical signs receded. The partial sequences of the amplified fragments of the pol and hexon genes were closest to those of adenoviruses identified in sea lions with fatal adenoviral hepatitis, and to a Genbank-deposited sequence obtained from a harbour porpoise.

Conclusion: These data suggest that adenovirus can cause self-limiting gastroenteritis in dolphins. This adenoviral infection can be detected by serology and by PCR detection in fecal material. Lack of signs of hepatitis in sick dolphins may reflect restricted tissue tropism or virulence of this adenovirus compared to those of the adenovirus identified in sea lions. Gene sequence-based phylogenetic analysis supports a common origin of adenoviruses that affect sea mammals. Our findings suggest the need for vigilance against adenoviruses in captive and wild dolphin populations.

No MeSH data available.


Related in: MedlinePlus

Presence of adenoviral DNA in fecal samples of four diseased bottlenose dolphins. A) Variation in the intensity of the adenoviral polymerase (pol) amplicon across different diseased animals and samples taken at the indicated times from the same animal. Black bars indicate the period during which each animal exhibited clinical manifestations. Day 1 was the day on which the first animal became overtly sick with vomiting and diarrhea. B) Representative results showing four levels of band intensity (- / + / ++ / +++) for the PCR amplicons of a region of the adenoviral pol gene. Line 1 corresponds to an amplification prepared from a fecal sample taken on day 2 from animal 2; Line 2, from a fecal sample taken on day 1 from animal 1; Line 3, on day 15 from animal 3; and Line 4, on day 20 from animal 4, used as negative controls. On the DNA ladder, the band of 500 bp is indicated.
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Fig1: Presence of adenoviral DNA in fecal samples of four diseased bottlenose dolphins. A) Variation in the intensity of the adenoviral polymerase (pol) amplicon across different diseased animals and samples taken at the indicated times from the same animal. Black bars indicate the period during which each animal exhibited clinical manifestations. Day 1 was the day on which the first animal became overtly sick with vomiting and diarrhea. B) Representative results showing four levels of band intensity (- / + / ++ / +++) for the PCR amplicons of a region of the adenoviral pol gene. Line 1 corresponds to an amplification prepared from a fecal sample taken on day 2 from animal 2; Line 2, from a fecal sample taken on day 1 from animal 1; Line 3, on day 15 from animal 3; and Line 4, on day 20 from animal 4, used as negative controls. On the DNA ladder, the band of 500 bp is indicated.

Mentions: At the end of September 2013, four captive bottlenose dolphins (Tursiops truncatus) in a total population of 14 individuals, all born at the Oceanográfic water park (www.cac.es/oceanografic) in the City of the Arts and the Sciences, Valencia (Spain), presented with anorexia, diarrhoea and vomiting. The four animals, aged 4-10 years, displayed no cough, respiratory disturbances or conjunctival infection. The other 10 dolphins in the same cohort remained healthy throughout this study. As soon as clinical signs became evident in the sick animals, they were isolated in a separate pool. The clinical signs of one dolphin (animal 1) appeared to be the mildest and it recovered in 1 week without treatment; in Figure 1A, the dark horizontal bar marks the period during which clinical manifestations were present. The other three dolphins (animals 2-4) were more severely affected and were administered oral rehydration therapy to compensate for fluid lost through vomiting and diarrhoea. They underwent longer disease-manifesting periods (Figure 1A). Day 1 was the day on which the first animal became overtly sick with vomiting and diarrhea.Figure 1


Novel adenovirus detected in captive bottlenose dolphins (Tursiops truncatus) suffering from self-limiting gastroenteritis.

Rubio-Guerri C, García-Párraga D, Nieto-Pelegrín E, Melero M, Álvaro T, Valls M, Crespo JL, Sánchez-Vizcaíno JM - BMC Vet. Res. (2015)

Presence of adenoviral DNA in fecal samples of four diseased bottlenose dolphins. A) Variation in the intensity of the adenoviral polymerase (pol) amplicon across different diseased animals and samples taken at the indicated times from the same animal. Black bars indicate the period during which each animal exhibited clinical manifestations. Day 1 was the day on which the first animal became overtly sick with vomiting and diarrhea. B) Representative results showing four levels of band intensity (- / + / ++ / +++) for the PCR amplicons of a region of the adenoviral pol gene. Line 1 corresponds to an amplification prepared from a fecal sample taken on day 2 from animal 2; Line 2, from a fecal sample taken on day 1 from animal 1; Line 3, on day 15 from animal 3; and Line 4, on day 20 from animal 4, used as negative controls. On the DNA ladder, the band of 500 bp is indicated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4352565&req=5

Fig1: Presence of adenoviral DNA in fecal samples of four diseased bottlenose dolphins. A) Variation in the intensity of the adenoviral polymerase (pol) amplicon across different diseased animals and samples taken at the indicated times from the same animal. Black bars indicate the period during which each animal exhibited clinical manifestations. Day 1 was the day on which the first animal became overtly sick with vomiting and diarrhea. B) Representative results showing four levels of band intensity (- / + / ++ / +++) for the PCR amplicons of a region of the adenoviral pol gene. Line 1 corresponds to an amplification prepared from a fecal sample taken on day 2 from animal 2; Line 2, from a fecal sample taken on day 1 from animal 1; Line 3, on day 15 from animal 3; and Line 4, on day 20 from animal 4, used as negative controls. On the DNA ladder, the band of 500 bp is indicated.
Mentions: At the end of September 2013, four captive bottlenose dolphins (Tursiops truncatus) in a total population of 14 individuals, all born at the Oceanográfic water park (www.cac.es/oceanografic) in the City of the Arts and the Sciences, Valencia (Spain), presented with anorexia, diarrhoea and vomiting. The four animals, aged 4-10 years, displayed no cough, respiratory disturbances or conjunctival infection. The other 10 dolphins in the same cohort remained healthy throughout this study. As soon as clinical signs became evident in the sick animals, they were isolated in a separate pool. The clinical signs of one dolphin (animal 1) appeared to be the mildest and it recovered in 1 week without treatment; in Figure 1A, the dark horizontal bar marks the period during which clinical manifestations were present. The other three dolphins (animals 2-4) were more severely affected and were administered oral rehydration therapy to compensate for fluid lost through vomiting and diarrhoea. They underwent longer disease-manifesting periods (Figure 1A). Day 1 was the day on which the first animal became overtly sick with vomiting and diarrhea.Figure 1

Bottom Line: In marine mammals, adenovirus has been associated with fatal hepatitis in sea lions.This adenoviral infection can be detected by serology and by PCR detection in fecal material.Our findings suggest the need for vigilance against adenoviruses in captive and wild dolphin populations.

View Article: PubMed Central - PubMed

Affiliation: VISAVET Center and Animal Health Department, Veterinary School, Complutense University of Madrid, Av Puerta del Hierro s/n, 28040, Madrid, Spain. consuelo@sanidadanimal.info.

ABSTRACT

Background: Adenoviruses are common pathogens in vertebrates, including humans. In marine mammals, adenovirus has been associated with fatal hepatitis in sea lions. However, only in rare cases have adenoviruses been detected in cetaceans, where no clear correlation was found between presence of the virus and disease status.

Case presentation: A novel adenovirus was identified in four captive bottlenose dolphins with self-limiting gastroenteritis. Viral detection and identification were achieved by: PCR-amplification from fecal samples; sequencing of partial adenovirus polymerase (pol) and hexon genes; producing the virus in HeLa cells, with PCR and immunofluorescence detection, and with sequencing of the amplified pol and hexon gene fragments. A causative role of this adenovirus for gastroenteritis was suggested by: 1) we failed to identify other potential etiological agents; 2) the exclusive detection of this novel adenovirus and of seropositivity for canine adenoviruses 1 and 2 in the four sick dolphins, but not in 10 healthy individuals of the same captive population; and 3) the virus disappeared from feces after clinical signs receded. The partial sequences of the amplified fragments of the pol and hexon genes were closest to those of adenoviruses identified in sea lions with fatal adenoviral hepatitis, and to a Genbank-deposited sequence obtained from a harbour porpoise.

Conclusion: These data suggest that adenovirus can cause self-limiting gastroenteritis in dolphins. This adenoviral infection can be detected by serology and by PCR detection in fecal material. Lack of signs of hepatitis in sick dolphins may reflect restricted tissue tropism or virulence of this adenovirus compared to those of the adenovirus identified in sea lions. Gene sequence-based phylogenetic analysis supports a common origin of adenoviruses that affect sea mammals. Our findings suggest the need for vigilance against adenoviruses in captive and wild dolphin populations.

No MeSH data available.


Related in: MedlinePlus