Neurobrucellosis in a common bottlenose dolphin (Tursiops truncatus) stranded in the Canary Islands.

BACKGROUND: Brucella spp. isolation is increasingly reported in cetaceans, although associated pathologies, including lesions of the musculoskeletal and nervous systems, are less frequently described. Concerning the nervous system, Brucella sp. infection causing meningitis, meningoencephalitis or meningoencephalomyelitis have been extensively reported in striped dolphins (Stenella coeruleoalba), and less frequently in other cetacean species. CASE PRESENTATION: A juvenile female common bottlenose dolphin (Tursiops truncatus) was found stranded alive in Lanzarote (Canary Islands, Spain) in 2005, but died shortly after. On physical examination, the dolphin showed a moderate body condition and was classified as code 2 (fresh dead) at the time of necropsy. The main gross findings were severe multiorgan parasitism, thickened and congested leptomeninges, and (sero)fibrino-suppurative and proliferative arthritis of the shoulder joint. Histopathological examination revealed the distinct features of a sub-acute systemic disease associated with Cetacean Morbillivirus (CeMV) infection. However, brain lesions diverged from those reported in systemic CeMV infection. This led to suspect that there was a coinfecting pathogen, based on the characteristics of the inflammatory response and the lesion distribution pattern in the central nervous system. Brucella sp. was detected in the brain tissue by PCR and Brucella antigen was demonstrated by immunohistochemistry in the brain and shoulder joint lesions. CONCLUSIONS: The zoonotic potential of marine mammal strains of Brucella has been demonstrated both in natural and laboratory conditions. In this study, PCR detected Brucella sp. in the brain of a common bottlenose dolphin stranded in the Canary Islands; the dolphin was also co-infected with CeMV. This is the first detection of Brucella sp. infection in a stranded cetacean in this archipelago. Therefore, we stress the importance of taking adequate measures during the handling of these species to prevent the transmissions of the infection to humans.

Prostatic Lesions in Odontocete Cetaceans.

The prostate is the only accessory male genital gland described in cetaceans. Although few studies describe the gross and histologic anatomy of the prostate in cetaceans, there is no information on pathological findings involving this organ. The prostate glands of 45 cetaceans, including 8 different odontocete species ( n = 44) and 1 mysticete, were evaluated. The main pathologic diagnoses were verminous prostatitis, septic prostatitis, viral prostatitis, benign prostatic hyperplasia, and prostatitis of unknown etiology. Verminous prostatitis ( n = 12) was caused by nematodes of the genus Crassicauda, and different presentations were observed. Septic prostatitis, identified in 2 cases, both involved nematode infestation and Clostridium spp coinfection. One case of viral prostatitis was identified and was associated with morbillivirus infection. In prostatitis of unknown cause ( n = 7), varying degrees of prostatic lesions, mostly chronic inflammation, were identified. Impacts at individual levels (eg, localized disease, loss of reproductive capacity) and population levels (eg, decreased reproductive success) are plausible. Our results indicate a high occurrence of prostatic lesions in free-ranging odontocetes. For this reason, the prostate should be routinely inspected and sampled during necropsy of odontocete cetaceans.

Morbillivirus infection in Risso's dolphin Grampus griseus: a phylogenetic and pathological study of cases from the Canary Islands.

The earliest evidence of cetacean morbillivirus (CeMV) infection dates from 1982, when the dolphin morbillivirus strain (DMV) was identified in bottlenose dolphins Tursiops truncatus stranded in the mid-Atlantic region. Since then, CeMV has been detected globally in at least 26 species of mysticetes and odontocetes, causing widespread mortality and a wide range of pathological effects. In the Canary Islands, DMV and pilot whale morbillivirus have been detected in cetacean species, including short-finned pilot whales Globicephala macrorhynchus and bottlenose dolphins. Risso's dolphins Grampus griseus have been reported year-round in waters of the Canary Islands and are considered a resident species. No information is currently available on CeMV prevalence in this species in this ocean region. We searched for evidence of CeMV infection in 12 Risso's dolphins stranded in the Canary Islands from 2003 to 2015 by means of histopathology, PCR and immunohistochemistry. PCR revealed 2 CeMV-positive animals (16.6%). Phylogenetic analysis showed that the strains from the 2 positive specimens were phylogenetically quite distant, proving that more than 1 strain infects the Risso's dolphin population in this region. We also determined that the strain detected in one of the specimens mainly circulated in the northeastern Atlantic Ocean from 2007 to 2013.

Fatal systemic morbillivirus infection in bottlenose dolphin, canary islands, Spain.

A systemic morbillivirus infection was diagnosed postmortem in a juvenile bottlenose dolphin stranded in the eastern North Atlantic Ocean in 2005. Sequence analysis of a conserved fragment of the morbillivirus phosphoprotein gene indicated that the virus is closely related to dolphin morbillivirus recently reported in striped dolphins in the Mediterranean Sea.

Retrospective study of etiologic agents associated with nonsuppurative meningoencephalitis in stranded cetaceans in the canary islands.

Nineteen natural cases of etiologically undetermined encephalitides in free-ranging cetaceans were studied retrospectively. Histological examination of the brains revealed variable degrees of nonsuppurative encephalitis or meningoencephalitis, characterized predominantly by perivascular lymphohistiocytic infiltrates. A PCR assay was used on brain and other available tissues to detect the presence of morbillivirus, herpesvirus, West Nile virus, Toxoplasma gondii, and Brucella spp. In addition, immunohistochemical (IHC) staining was performed on selected tissues to determine the presence of morbilliviral antigens. Six animals (5 striped dolphins and 1 common dolphin) showed IHC and/or molecular evidence of morbilliviral antigens and/or genomes, mainly in brain tissue. Conventional nested PCR detected herpesviral DNA in brain tissue samples from two striped dolphins. There was no evidence of West Nile virus, T. gondii, or Brucella spp. in any of the brain tissue samples examined. The information presented here increases the number of confirmed morbillivirus-positive cases within the Canarian archipelago from two previously reported cases to eight. Furthermore, a new nested-PCR method for the detection of morbillivirus is described here. Regarding herpesvirus, the phylogenetic analysis performed in the current study provides valuable information about a possible pathogenic branch of cetacean alphaherpesviruses that might be responsible for some fatal cases worldwide.

Histopathological Differential Diagnosis of Meningoencephalitis in Cetaceans: Morbillivirus, Herpesvirus, Toxoplasma gondii, Brucella sp., and Nasitrema sp.

Infectious and inflammatory processes are among the most common causes of central nervous system involvement in stranded cetaceans. Meningitis and encephalitis are among the leading known natural causes of death in stranded cetaceans and may be caused by a wide range of pathogens. This study describes histopathological findings in post-mortem brain tissue specimens from stranded cetaceans associated with five relevant infectious agents: viruses [Cetacean Morbillivirus (CeMV) and Herpesvirus (HV); n = 29], bacteria (Brucella sp.; n = 7), protozoa (Toxoplasma gondii; n = 6), and helminths (Nasitrema sp.; n = 1). Aetiological diagnosis was established by molecular methods. Histopathologic evaluations of brain samples were performed in all the cases, and additional histochemical and/or immunohistochemical stains were carried out accordingly. Compared with those produced by other types of pathogens in our study, the characteristic features of viral meningoencephalitis (CeMV and HV) included the most severe and frequent presence of malacia, intranuclear, and/or intracytoplasmic inclusion bodies, neuronal necrosis and associated neuronophagia, syncytia and hemorrhages, predominantly in the cerebrum. The characteristic features of Brucella sp. meningoencephalitis included the most severe and frequent presence of meningitis, perivascular cuffing, cerebellitis, myelitis, polyradiculoneuritis, choroiditis, ventriculitis, vasculitis, and fibrinoid necrosis of vessels. The characteristic features of T. gondii meningoencephalitis included lymphocytic and granulomatous encephalitis, tissue cysts, microgliosis, and oedema. In the case of Nasitrema sp. infection, lesions are all that we describe since just one animal was available. The results of this study are expected to contribute, to a large extent, to a better understanding of brain-pathogen-associated lesions in cetaceans.

Retrospective Study of Fishery Interactions in Stranded Cetaceans, Canary Islands.

Estimating cetacean interactions with fishery activities is challenging. Bycatch and chronic entanglements are responsible for thousands of cetacean deaths per year globally. This study represents the first systematic approach to the postmortem investigation of fishery interactions in stranded cetaceans in the Canary Islands. We retrospectively studied 586 cases necropsied between January 2000 and December 2018. Of the cases with a known cause of death, 7.4% (32/453) were due to fishery interactions, and the Atlantic spotted dolphin (Stenella frontalis) was the most affected species [46.9% (15/32)]. Three types of fishery interactions were recognized by gross findings: bycatch [65.6% (21/32)], chronic entanglements [18.8% (6/32)], and fishermen aggression [15.6% (5/32)]. Among the bycaught cases, we differentiated the dolphins that died because of ingestion of longline hooks [23.8% (5/21)] from those that died because of fishing net entrapments [76.2% (16/21)], including dolphins that presumably died at depth due to peracute underwater entrapment (PUE) [37.5% (6/16)], dolphins that were hauled out alive and suffered additional trauma during handling [43.8% (7/16)], and those that were released alive but became stranded and died because of fishery interactions [18.7% (3/16)]. Gross and histologic findings of animals in each group were presented and compared. The histological approach confirmed gross lesions and excluded other possible causes of death. Cetaceans in good-fair body condition and shallow diving species were significantly more affected by fishery interactions, in agreement with the literature. Low rates of fishery interactions have been described, compared with other regions. However, within the last few years, sightings of entangled live whales, especially the minke whale (Balaenoptera acutorostrata) and Bryde's whale (B. edeni), have increased. This study contributes to further improvement of the evaluation of different types of fishery interactions and may facilitate the enforcement of future conservation policies to preserve cetacean populations in the Canary Islands.

Comparative histopathologic and viral immunohistochemical studies on CeMV infection among Western Mediterranean, Northeast-Central, and Southwestern Atlantic cetaceans.

Cetacean morbillivirus (CeMV) is a major natural cause of morbidity and mortality in cetaceans worldwide and results in epidemic and endemic fatalities. The pathogenesis of CeMV has not been fully elucidated, and questions remain regarding tissue tropism and the mechanisms of immunosuppression. We compared the histopathologic and viral immunohistochemical features in molecularly confirmed CeMV-infected Guiana dolphins (Sotalia guianensis) from the Southwestern Atlantic (Brazil) and striped dolphins (Stenella coeruleoalba) and bottlenose dolphins (Tursiops truncatus) from the Northeast-Central Atlantic (Canary Islands, Spain) and the Western Mediterranean Sea (Italy). Major emphasis was placed on the central nervous system (CNS), including neuroanatomical distribution of lesions, and the lymphoid system and lung were also examined. Eleven Guiana dolphins, 13 striped dolphins, and 3 bottlenose dolphins were selected by defined criteria. CeMV infections showed a remarkable neurotropism in striped dolphins and bottlenose dolphins, while this was a rare feature in CeMV-infected Guiana dolphins. Neuroanatomical distribution of lesions in dolphins stranded in the Canary Islands revealed a consistent involvement of the cerebrum, thalamus, and cerebellum, followed by caudal brainstem and spinal cord. In most cases, Guiana dolphins had more severe lung lesions. The lymphoid system was involved in all three species, with consistent lymphoid depletion. Multinucleate giant cells/syncytia and characteristic viral inclusion bodies were variably observed in these organs. Overall, there was widespread lymphohistiocytic, epithelial, and neuronal/neuroglial viral antigen immunolabeling with some individual, host species, and CeMV strain differences. Preexisting and opportunistic infections were common, particularly endoparasitism, followed by bacterial, fungal, and viral infections. These results contribute to understanding CeMV infections in susceptible cetacean hosts in relation to factors such as CeMV strains and geographic locations, thereby establishing the basis for future neuro- and immunopathological comparative investigations.

Pathologic findings and causes of death of stranded cetaceans in the Canary Islands (2006-2012).

This study describes the pathologic findings and most probable causes of death (CD) of 224 cetaceans stranded along the coastline of the Canary Islands (Spain) over a 7-year period, 2006-2012. Most probable CD, grouped as pathologic categories (PCs), was identified in 208/224 (92.8%) examined animals. Within natural PCs, those associated with good nutritional status represented 70/208 (33.6%), whereas, those associated with significant loss of nutritional status represented 49/208 (23.5%). Fatal intra- and interspecific traumatic interactions were 37/208 (17.8%). Vessel collisions included 24/208 (11.5%). Neonatal/perinatal pathology involved 13/208 (6.2%). Fatal interaction with fishing activities comprised 10/208 (4.8%). Within anthropogenic PCs, foreign body-associated pathology represented 5/208 (2.4%). A CD could not be determined in 16/208 (7.7%) cases. Natural PCs were dominated by infectious and parasitic disease processes. Herein, our results suggest that between 2006 and 2012, in the Canary Islands, direct human activity appeared responsible for 19% of cetaceans deaths, while natural pathologies accounted for 81%. These results, integrating novel findings and published reports, aid in delineating baseline knowledge on cetacean pathology and may be of value to rehabilitators, caregivers, diagnosticians and future conservation policies.

Occurrence of strongyloidiasis in privately owned and sheltered dogs: clinical presentation and treatment outcome.

BACKGROUND: The increasing number of reports of human infections by Strongyloides stercoralis from a range of European countries over the last 20 years has spurred the interest of the scientific community towards this parasite and, in particular, towards the role that infections of canine hosts may play in the epidemiology of human disease. Data on the epidemiology of canine strongyloidiasis is currently limited, most likely because of the inherent limitations of current diagnostic methods. METHODS: Faecal samples were collected directly from the rectal ampulla of 272 animals of varying age and both genders living in Apulia, southern Italy. Dogs included were either privately owned (n = 210), living in an urban area but with unrestricted outdoor access (Group 1), or shelter dogs (n = 62 out of ~400) hosted in a single shelter in the province of Bari in which a history of diarrhoea, weight loss, reduced appetite and respiratory symptoms had been reported (Group 2). Strongyloides stercoralis infection was diagnosed by coproscopy on direct faecal smear and via the Baermann method. RESULTS: Six of 272 dogs were positive for S. stercoralis at the Baermann examination; all but one were from the shelter (Group 2) and displayed gastrointestinal clinical signs. The only owned dog (Group 1) infected with S. stercoralis, but clinically healthy, had been adopted from a shelter 1 year prior to sampling. Five infected dogs were treated with fenbendazole (Panacur®, Intervet, Animal Health, 50 mg/kg, PO daily for 5 days), or with a combination of fenbendazole and moxidectin plus imidacloprid spot-on (Im/Mox; Advocate® spot-on, Bayer). Post-treatment clearance of infection was confirmed in three dogs by Baermann examination, whereas treatment failure was documented in two dogs by Baermann and/or post-mortem detection of adult parasites. CONCLUSIONS: This study describes, for the first time, the presence of S. stercoralis infection in sheltered dogs from southern Italy. Data indicate that S. stercoralis infection may pose a concern for sheltered animals and raise questions on potential risks of infection for staff of municipal shelters in southern European countries. Given that a single course of treatment with fenbendazole, associated or not with Im/Mox spot-on, may not eliminate the infection, effective treatment protocols should be investigated and control strategies targeting the environment considered for reducing the risk of zoonotic infection.

Cytokine expression in lungs of calves spontaneously infected with Mycoplasma bovis.

Cytokine expression in the lung can play an important role during Mycoplasma bovis infection through leukocyte recruitment and activation, and the induction of a broad array of inflammatory mediators. To gain further insight into the pathogenesis of M. bovis-associated pneumonia, cytokine expression was examined, by immunohistochemical methods in formalin-fixed, paraffin wax-embedded tissues, in the lung of 20 calves spontaneously infected. Immunolabelling for tumor necrosis factor alpha (TNF)-α, interleukin-4 (IL-4), IL-10 and interferon-gamma (IFN-γ), was usually associated with pneumonia, particularly in macrophages and lymphocytes, and with the presence of M. bovis antigen. The expression was minimal in lungs from negative controls. The results demonstrated consistent upregulation of TNF-α, IL-4, IL-10 and IFN-γ expression during M. bovis-associated pneumonic lesions. These cytokines can participate in the immune and inflammatory responses during the pulmonary defense mechanisms against M. bovis infection.