Fernando Esperón

Morbillivirus and Pilot Whale Deaths, Mediterranean Sea

An outbreak of a lethal morbillivirus infection of long-finned pilot whales occurred in the Mediterranean Sea from the end of October 2006 through April 2007. Sequence analysis of a 426-bp conserved fragment of the morbillivirus phosphoprotein gene indicates that the virus is more closely related to dolphin morbillivirus than to pilot whale morbillivirus.

Screening for several potential pathogens in feral pigeons (Columba livia) in Madrid.

BackgroundPathogens with the zoonotic potential to infect humans, such as Campylobacter jejuni, Campylobacter coli and Chlamydophila psittaci, can be found in feral pigeons (Columba livia). Given the high density of these birds in the public parks and gardens of most cities, they may pose a direct threat to public health.MethodsA total of 118 pigeons were captured in three samplings carried out in 2006-2007 in public parks and gardens in Madrid, Spain. Standard haematological and morphological analyses were carried out on the pigeons. PCR was used to screen for the presence of Campylobacter jejuni, C. coli and Chlamydophila psittaci. Positive samples were confirmed by DNA sequencing.ResultsThe analyses demonstrated a high prevalence of Chlamydophila psittaci (52.6%) and Campylobacter jejuni (69.1%) among the birds captured. In contrast, Campylobacter coli was rarely detected (1.1%).ConclusionsPigeons in Madrid can carry Chlamydophila psittaci and Campylobacter jejuni. They may be asymptomatic or subclinical carriers of both pathogens.

Phylogenetic analysis of a new Cetacean morbillivirus from a short-finned pilot whale stranded in the Canary Islands

Cetacean morbillivirus (CeMV) is considered the most pathogenic virus in cetaceans. Three strains have been already described: the dolphin morbillivirus (DMV), the porpoise morbillivirus (PMV) and the tentatively named pilot whale morbillivirus (PWMV). This study describes the molecular characterization of a strain of CeMV detected in the brain of a short-finned pilot whale that had stranded in the Eastern Atlantic Ocean around the Canary Islands and that showed lesions compatible with morbilliviral disease. Sequences for the nucleoprotein, phosphoprotein, fusion protein and haemagglutinin genes were obtained. The phylogenetic study showed high homology (97%) with the PWMV strain previously detected from a long-finned pilot whale stranded in the Western Atlantic Ocean. These results support the existing classification of CeMV into three principal genetic clusters.

Presence of herpesvirus in striped dolphins stranded during the cetacean morbillivirus epizootic along the Mediterranean Spanish coast in 2007

A screening for herpesvirus (HV) was carried out using a tissue bank obtained from the cetacean morbillivirus (CeMV) mortality episode that occurred along the Mediterranean Spanish coast in 2007. A total of 14 cetaceans, including six long-finned pilot whales and eight striped dolphins, were studied using histopathology and molecular analysis to detect HV and CeMV. In five of the eight dolphins (62.5%) infected with CeMV, eight novel HV sequences were also detected. No HV lesions were found in any of the coinfected dolphins, which may indicate that HV did not contribute to the mortality in the CeMV outbreak. This is the first report of HV infection in any cetacean from the Mediterranean Sea.

Molecular diagnosis of lobomycosis-like disease in a bottlenose dolphin in captivity

We report the diagnosis and molecular characterization of lobomycosis-like lesions in a captive bottlenose dolphin. The clinical picture and the absence of growth in conventional media resembled the features associated with Lacazia loboi. However sequencing of ribosomal DNA and further phylogenetic analyses showed a novel sequence more related to Paracoccidioides brasilensis than to L. loboi. Moreover, the morphology of the yeast cells differed from those L. loboi causing infections humans. These facts suggest that the dolphin lobomycosis-like lesions might have been be caused by different a different fungus clustered inside the order Onygenales. A successful treatment protocol based on topic and systemic terbinafine is also detailed.

Genetic comparison among dolphin morbillivirus in the 1990–1992 and 2006–2008 Mediterranean outbreaks

In 1990, dolphin morbillivirus (DMV) killed thousands of striped dolphins in the Mediterranean. Subsequently, the prevalence of the infection declined in this species. In 2006-2008, the virus killed not only numerous striped dolphins but also long-finned pilot whales. All partial sequences of the phosphoprotein and nucleoprotein genes obtained thus far from different host species during the 2006-2008 outbreak show 100% identity, suggesting that a single virus was involved, and these sequences are nearly identical to the 1990 Spanish strain. Here our first objective was to determine the sequence identity between the morbillivirus from the 2006-2008 outbreak and the 1990 Spanish strain by sequencing more extensive genomic regions of strains from one pilot whale and one striped dolphin stranded in 2007. The second objective was to investigate the relationship between the 1990 and 2007 strains by constructing a phylogenetic tree based on the phosphoprotein gene to compare several Cetacean morbilliviruses, and another tree based on the nearly complete genomes of Mediterranean DMV. The third objective was to identify the most variable regions in the DMV genomes. Results showed that the two 2007 Spanish strains were 99.9% identical over 9050 bp and should be considered the same virus, and that this virus is 99.3-99.4% similar to the 1990 Spanish strain. The phylogenetic trees, together with the common geographical area for the two outbreaks, suggest that the 2007 DMV strains evolved from the 1990 DMV strain. Pilot whales do not seem to have been exposed or infected during the 1990-1992 epidemic, since these populations appeared to be immunologically naïve in 2006-2008. Our results suggest that the virus may have evolved in striped dolphin populations prior to the 2006-2008 outbreak, after which it entered the long-finned pilot whale, perhaps aided by an alanine to valine mutation in the N-terminal domain of the fusion protein.

Herpes simplex-like infection in a bottlenose dolphin stranded in the Canary Islands

A bottlenose dolphin, stranded in the Canary Islands in 2001 exhibited non-suppurative encephalitis. No molecular detection of cetacean morbillivirus (CeMV) was found, but a herpesviral-specific band of 250 bp was detected in the lung and brain. The sequenced herpesviral PCR product was compared with GenBank sequences, obtaining 98% homology (p-distance of 0.02) with Human herpesvirus 1 (herpes simplex virus 1 or HSV-1). This is the first report of a herpes simplex-like infection in a stranded dolphin.

Simultaneous diagnosis of Cetacean morbillivirus infection in dolphins stranded in the Spanish Mediterranean sea in 2011 using a novel Universal Probe Library (UPL) RT-PCR assay.

A highly sensitive and specific real-time (rt) RT-PCR assay has been developed for rapid, simultaneous detection of three strains of cetacean morbillivirus (CeMV). In this assay, two PCR primers and a hydrolysis probe from a commercially available Universal Probe Library (UPL) are used to amplify a highly conserved region within the fusion protein gene. RT-PCR is carried out on the same sample using two primer sets in parallel: one set detects the more virulent strains, dolphin morbillivirus (DMV) and porpoise morbillivirus (PMV), and the other set detects the least virulent and least common strain, pilot whale morbillivirus (PWMV). Sensitivity analysis using dilute samples containing purified DMV, PMV and PWMV showed that viral RNA detection limits in this UPL RT-PCR assay were lower than in a conventional RT-PCR assay. Our method gave no amplification signal with field samples positive for viruses related and unrelated to CeMV, such as phocine distemper virus (PDV). The reliability and robustness of the UPL RT-PCR assay were verified using tissue samples previously analyzed by conventional methods, as well as a panel of clinical samples suspected of containing CeMV. Using the UPL RT-PCR assay, we were able to associate DMV with a mass stranding of striped dolphins in the Spanish Mediterranean in 2011 with greater reliability than was possible with a conventional RT-PCR method. These results suggest that this UPL RT-PCR method is more sensitive and specific than the conventional approach, and that it may be an affordable and rapid test for routine diagnosis of three CeMV strains.

Herpesvirus infection with severe lymphoid necrosis affecting a beaked whale stranded in the Canary Islands

This report describes the pathologic findings in a single, adult female Cuviers beaked whale Ziphius cavirostris stranded in the Canary Islands. The study indicated that this whale died with a severe, systemic, herpesviral infection and clearly exhibited lesions different from those of the fat and gas embolic syndrome described in beaked whale mass strandings associated with sonar exposure. This is the first report of a cetacean alphaherpesvirus infection of the lymphoid system in a beaked whale.

Herpes virus infection associated with interstitial nephritis in a beaked whale (Mesoplodon densirostris)

BackgroundThe capacity for herpesvirus to cause disease in cetaceans is unclear and may be varied depending on the different conditions of individuals and between different species. Kidney pathology and intralesional virus-associated infection have been rarely reported in cetaceans.ResultOn April 2004, an old adult male Blainville’s beaked whale (Mesoplodon densirostris) 420 cm long with a poor body condition was stranded on Tenerife Island. During necropsy, no gross lesions were observed in the kidneys. However, membranous glomerulonephritis, multifocal interstitial lymphoplasmacytic nephritis and acute multifocal necrotizing tubulointerstitial nephritis with intranuclear inclusion bodies was diagnosed by histological analysis. Tissue samples were submitted for bacteriological analysis and molecular viral screening.ConclusionA novel alpha herpesvirus associated with interstitial nephritis was identified in an old adult male Blainvilles beaked whale (M. densirostris) with a poor body condition stranded in the Canary Islands. This report suggests that identification of herpesvirus infection could be used as a differential diagnosis for interstitial nephritis in cetaceans.