Molecular identification and microscopic characterization of poxvirus in a Guiana dolphin and a common bottlenose dolphin, Brazil

Abstract

The poxviruses identified in cetaceans are associated with characteristic tattoo or ring skin lesions. However, little is known regarding the prevalence and progression of these lesions and the molecular characterization of cetacean poxviruses in the Southern Hemisphere. This manuscript describes the progression of poxvirus-like skin lesions in 5 free-ranging Guiana dolphins Sotalia guianensis. Additionally, 151 skin samples from 113 free-ranging cetaceans from Brazil, including 4 animals with tattoo skin lesions, were selected for poxvirus testing. Poxviral DNA polymerase gene PCR amplification was used to detect the virus in β-actin-positive samples (145/151). DNA topoisomerase I gene PCR was then used in Cetaceanpoxvirus (CePV)-positive cases (n = 2), which were further evaluated by histopathology and electron microscopy. Based on photo-identification, adult Guiana dolphins presented regressing or healed poxvirus-like lesions (2/2), while juveniles presented persistent (2/3) or healed and progressive lesions (1/3). CePV DNA was amplified in a common bottlenose dolphin Tursiops truncatus and in a Guiana dolphin. Intracytoplasmic inclusion bodies and viral particles consistent with poxvirus were identified by histology and electron microscopy, respectively. CePV-specific amino acid motifs were identified through phylogenetic analysis. Our findings corroborate previous studies that suggest the placement of poxviruses from cetaceans within the novel CePV genus. This is the first molecular identification of poxvirus in South American odontocetes.

The Pathology of Cetacean Morbillivirus Infection and Comorbidities in Guiana Dolphins During an Unusual Mortality Event (Brazil, 2017–2018)

“…Cetaceanpoxvirus has been reported in a wide spectrum of hosts, and in Brazil, molecularly confirmed cases are limited to bottlenose dolphins and Guiana dolphins. 55 Herpesvirus has been previously described in 2 Guiana dolphins, 54,62 but infection was not confirmed in the 3 cases tested in this study. The significance of these potential viral coinfections with CeMV is unknown.…”

“…Cetaceanpoxvirus-PCR-positive “tattoo-like skin lesions” from a Guiana dolphin and an Atlantic bottlenose dolphin ( Tursiops truncatus ; MF458199 and KU726611, respectively) were used as positive controls for poxvirus. 55 Diethylpyrocarbonate-treated water was used as no template control. Amplicons were electrophoresed and visualized (Syber Safe, Invitrogen), and positive samples were directly sequenced by the Sanger method and compared with those available in public databases using a BLAST search.…”

Pathological Findings in Cetaceans Sporadically Stranded Along the Chilean Coast

“…The macroscopic aspect of the skin lesions in one Burmesteir's porpoise, characterized by clear internal area, and stippled aspect surrounded by dark margins, is compatible with an advanced tattoo lesion (Geraci et al, 1979). Histopathological findings were consistent with previous description of Cetacean poxvirus-like lesions (CePV; Sacristán et al, 2018) or tattoo-skin disease (Van Bressem et al, 2009), although the role of other viral pathogens such as herpesvirus and papillomavirus cannot be ruled out. Unfortunately, we could not assess the etiology of these tattoo lesions through molecular analyses, but regardless of their origin, it is known that these type of skin lesions can be an indicator of poor health status.…”

Long-Term Consequences of High Polychlorinated Biphenyl Exposure: Projected Decline of Delphinid Populations in a Hotspot for Chemical Pollution

“…In addition to being a hotspot of chemical pollutants that act as an underlying factor leading to an important reduction in immunological function, these regions are also a hotspot for etiological agents . Several viruses, bacteria, and parasites have already been identified in delphinids from the SE region, such as morbillivirus, poxvirus, helminths, and Toxoplasma gondii . − Some of those are strongly associated with declines in population size by interfering in reproductive processes, increase in mortality rates, and/or vulnerability to other diseases . It is important to note that the same pathogens have been recorded affecting dolphins found stranded on the Brazilian coast, including rough-toothed dolphins from S Brazil. , There is increasing alarm regarding emerging infectious diseases in cetaceans, their pathogeny in vulnerable populations, and interaction with immunosuppressant cofactors, such as chemical pollutants .…”