Dolphin Morbillivirus in a Cuvier's Beaked Whale (Ziphius cavirostris), Italy

Abstract

Dolphin morbillivirus (DMV) has caused several mortality events in Mediterranean striped (Stenella coeruleoalba) and bottlenose (Tursiops truncatus) dolphins populations since 19; in the last 5 years, the virus was reported to infect new hosts in this basin, such as fin whales (Balaenoptera physalus), sperm whales (Physeter macrocephalus), and even a harbor seal (Phoca vitulina). Very recently, a calf Cuvier's beaked whale (Ziphius cavirostris) calf stranded on the Southern Italian coastline with mild pathological findings suggestive of morbilliviral infection, received the first confirmation of DMV infection in this species by biomolecular evidences on lung tissue. This new cross-species infection report, along with 19% of the cetaceans specimens examined by the Italian Stranding Network being found positive to DMV, support the hypothesis of an endemic circulation of this virus among Mediterranean cetaceans.

Keywords: Cuvier’s beaked whale; Mediterranean Sea; cross-species infection; dolphin morbillivirus; virology.

FIGURE 1

Haematoxylin and eosin-stained lung tissue section from Cuvier’s beaked whale (Ziphius cavirostris) calf stranded off the Southern Italian coastline. Fibrinous bronco-pneumonia, associated with necrotizing bronchiolitis. (A) Necrotic cellular debris is shown within the airways. (B) Depots of fibrinous membranes (hyaline membrane, arrows) are seen covering the alveolar epithelium, along with a mild neutrophilic infiltration. Original magnification × 20.

FIGURE 2

Maximum likelihood phylogenetic tree reconstructed based on a collection of dolphin morbillivirus (DMV) and PWMV (used as outgroup) partial (285 nucleotides) sequences of the P gene. The robustness of each clade monophyly has been evaluated using a fast non-parametric version of the aLRT (Shimodaira–Hasegawa [SH]-aLRT), developed and implemented in the PhyML3.0 (values are displayed near to the corresponding node). The strain reported in the present study has been showed in red.