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Postmortem Findings in Four South American Sea Lions ( Otaria byronia ) from an Urban Colony in Valdivia, Chile

DOI:10.7589/2013-07-161
Authors:
Maximiliano A Sepúlveda at The Pew Charitable Trusts
Maximiliano A Sepúlveda
Mauricio Seguel at University of Guelph
Mauricio Seguel
Mario Alvarado-Rybak at Universidad de las Américas (Chile)
Mario Alvarado-Rybak
Claudio Verdugo at Universidad Austral de Chile
Claudio Verdugo
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Abstract We performed postmortem examination on four South American sea lions (Otaria byronia) from an urban colony in Valdivia, Chile. Chronic leptospirosis and suspected morbillivirus-like infection were diagnosed in one individual. Antibodies against Toxoplasma gondii and the zoonotic helminthes Contracaecum sp., Pseudoterranova sp., and Diphyllobothrium sp. were also detected.
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Postmortem Findings in Four South American Sea Lions (Otaria byronia)
from an Urban Colony in Valdivia, Chile
Author(s): Maximiliano A. Sepúlveda, Mauricio Seguel, Mario Alvarado-Rybak, Claudio
Verdugo, Claudia Muñoz-Zanzi, and Rafael Tamayo
Source: Journal of Wildlife Diseases, 51(1):279-282. 2015.
Published By: Wildlife Disease Association
URL: http://www.bioone.org/doi/full/10.7589/2013-07-161
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LETTERS
DOI: 10.7589/2013-07-161 Journal of Wildlife Diseases, 51(1), 2015, pp. 279–282
#
Wildlife Disease Association 2015
Postmortem Findings in Four South American Sea Lions
(Otaria byronia) from an Urban Colony in Valdivia, Chile
Maximiliano A. Sepu´lveda,
1,6,7
Mauricio Seguel,
2,5
Mario Alvarado-Rybak,
3
Claudio Verdugo,
3
Claudia Mun˜ oz-Zanzi,
1,4
and Rafael Tamayo
11
Instituto de Medicina Preventiva Veterinaria, Facultad de
Ciencias Veterinarias, Universidad Austral de Chile, Campus Isla Teja s/n, Valdivia, Chile;
2
Laboratorio de Estudios
en Biologı
´a y Conservacio´n de Mamı
´feros y Aves Acua´ticas, Universidad Austral de Chile, Campus Isla Teja s/n,
Valdivia, Chile;
3
Instituto de Patologı
´a Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile,
Campus Isla Teja s/n, Valdivia, Chile;
4
Division of Epidemiology and Community Health, School of Public Health,
University of Minnesota, 1300 S Second St., Suite 300, Minneapolis, Minnesota 55454, USA;
5
Department of
Pathology, College of Veterinary Medicine, University of Georgia, 501 D. W. Brooks Dr #148, Athens, Georgia
30602, USA;
6
Current address: Center of Applied Ecology and Sustainability (CAPES), Pontificia Universidad
Cato´lica de Chile, Alameda 340, Santiago, Chile;
7
Corresponding author (email: msepulveda@bio.puc.cl)
ABSTRACT:
We performed postmortem exam-
ination on four South American sea lions
(Otaria byronia) from an urban colony in
Valdivia, Chile. Chronic leptospirosis and
suspected morbillivirus-like infection were
diagnosed in one individual. Antibodies against
Toxoplasma gondii and the zoonotic helminthes
Contracaecum sp., Pseudoterranova sp., and
Diphyllobothrium sp. were also detected.
A resident, nonbreeding, small group of
South American sea lions (SASLs; Otaria
byronia) has been present since the mid-
1970s in the center of Valdivia, southern
Chile (39u489S, 73u149W) (Schlatter 1976).
This small group consists of approximately
of 50 juvenile, subadult, and adult males.
Because SASLs use publicspaces, there is a
risk of pathogen transmission between
SASLs and humans and their pets. We
performed postmortem examination in four
SASLs to determine cause of death and
assess presence of relevant pathogens.
Between March 2008 and December
2010 we necropsied four SASLs and per-
formed ancillary diagnostic studies. Two
SASLs (SASLs 1 and 2) were part of an
ecologic study and died during routine
anesthesia (1.2 mg/kg of tiletamin/zolaze-
pam, ZoletilH, delivered intramuscularly)
(Haulena 2008). Both animals died despite
being apparently healthy at the time of
darting. The two additional sea lions (SASL
3 and 4) were found emaciated on the
shore of the Valdivia River and died within
24 h of discovery. Serum samples to detect
antibodies against canine distemper virus
(CDV), canine parvovirus-2 (CPV-2),
Toxoplasma gondii,Leptospira interrogans
serovars Pomona, Icterohaemorrhagiae,
Hardjo, Bratislava, Copenhageni, Canicola;
Leptospira kirschneri serovar Grippoty-
phosa; and Leptospira biflexa serovar Patoc
were collected premortem from SASLs 1,
2, and 4. Blood from SASL 3 was plated on
MacConkey and blood agars.
Complete necropsies were performed
on all SASLs within 24 h of death.
Sections from major organs and tissues
(including brain) were fixed in 10%
neutral buffered formalin and processed
for histopathology. Samples of lung, liver,
and mesenteric, bronchial, and mediasti-
nal lymph nodes were collected from
SASLs 3 and 4 and were processed and
cultured, and the microorganisms were
identified by standard bacteriologic tech-
niques (Barrow and Feltham 2004). Gas-
trointestinal parasites were placed in 70%
ethanol and identified by light microscopy
(Carvajal et al. 1983; Mercado et al. 2010).
Immunohistochemistry (IHC) using a
monoclonal antibody against CDV nucle-
oprotein was performed on lung, medias-
tinal lymph node, brain, spleen, and
bladder (Stone et al. 2011). We also
performed IHC on kidney samples using
aLeptospira-specific polyclonal antibody
against L. interrogans serovars Bratislava,
279
Canicola, Hardjo, Icterohaemorrhagiae,
and Pomona, and against L. kirschneri
Grippotyphosa (Colegrove et al. 2005).
Serologic results are shown in Table 1.
Sea lion 1 was a 200-cm, 320-kg, adult
male. Antibodies to CDV (1:8), CPV-2
(1:64), and L. interrogans serovars Pomona
and Bratislava (.1:400) were detected. At
histopathology there was mild, nonsuppu-
rative meningoencephalitis and moderate,
multifocal neutrophilic and lymphoplasma-
cytic bronchopneumonia with epithelial
necrosis and abundant deposition of fibrin
in the bronchioles. Occasional bronchiolar
gland epithelial cells presented mild in-
tracytoplasmatic staining for morbillivirus
antigen. There was moderate multifocal
lymphoplasmacytic interstitial nephritis
and a few leptospires detected in the
renal tubules with the Warthin-Starry
silver stain and IHC (Fig. 1). Sea lion 2
was a 210-cm, 250-kg, adult male. Anti-
bodies against CPV-2 (1:64) and Toxo-
plasma gondii (1:256) were detected. The
same pattern of bronchopneumonia ob-
served in SASL 1 was found in SASL 2
but was milder. Sea lion 3 was a 120-cm,
65-kg, juvenile male. On postmortem
examination, 70%of the lung paren-
chyma presented a marked multifocal to
coalescing bronchointerstitial histiocytic
pneumonia. Gram-negative bacilli and
Gram-positive cocci were observed inside
macrophages in the lung, spleen, and
mediastinal and axillary lymph nodes.
There was moderate lymphoid depletion
in the spleen and most lymph nodes.
Proteus mirabilis and Staphylococcus sp.
(nonhemolytic) were isolated from lung,
spleen, and mediastinal and axillar lymph
nodes. Protozoal cysts (probably Sarcocys-
tis sp.) were found in the skeletal muscles.
Sea lion 4 was a 180-kg, 160-cm, subadult
male with antibodies against CDV (1:8)
and CPV-2 (1:8). This animal presented
the same pattern of bronchointerstitial
pneumonia found in SASL 3. Escherichia
coli and a nonhemolytic Staphylococcus
T
ABLE
1. Antibody titers against selected pathogens in three South American sea lions (Otaria byronia),
Valdivia, Chile, between 2008–10.
Pathogen
a
Antibody titers
b
Test performedSea lion 1 Sea lion 2 Sea lion 4
CDV
c
1:8 NR 1:8 Viral seroneutralization
CPV-2
d
1:64 1:64 1:8 Hemagglutination Inhibition
Leptospira interrogans serovar
Bratislava
d
1:800 NR NA Microagglutination
L. interrogans serovar Hardjo
c,d
NR NR NR Microagglutination
L. interrogans serovar
Icterohaemorrhagiae
d
NR NR NA Microagglutination
L. interrogans serovar Pomona
c,d
1:400, 1:800
e
NR NR Microagglutination
L. interrogans serovar Copenhageni
c
NR NR NR Microagglutination
L. interrogans serovar Canicola
c,d
NR NR NR Microagglutination
Leptospira kirschneri serovar
Grippotyphosa
c,d
NR NR NR Microagglutination
Leptospira biflexa serovar Patoc
d
1:200 1:100 NA Microagglutination
Brucella abortus
c
NR NR NR Bengal rose
Brucella canis
d
NR NR NR Plaque agglutination
Brucella sp.
d
NR NR NR Plaque agglutination
Toxoplasma gondii
d
NR 1:256 NA Latex agglutination
a
CDV 5canine distemper virus; CPV-2 5canine parvovirus-2.
b
NR 5not reactive; NA 5not analyzed.
c
Tests performed at the Chilean Agricultural and Livestock Department Laboratories.
d
Tests performed in the laboratories of the College of Veterinary Medicine, University of Minnesota.
e
Both titers are shown when results from the two laboratories were different.
280 JOURNAL OF WILDLIFE DISEASES, VOL. 51, NO. 1, JANUARY 2015
sp. were isolated from lung, spleen, and
mesenteric and mediastinal lymph nodes.
Sea lions 1, 2, and 4 had severe
infections with the nematodes Contracae-
cum sp. and Pseudoterranova sp. A few
tapeworms (Diphyllobotrium sp.) were
found in SASLs 1 and 2. Sea lion 3 had
a low number of the trematode Ogmoga-
ster heptalineatus. The only histopa-
thologic change associated with these
parasites was moderate eosinophilic gas-
tritis in animals infected with Contracae-
cum sp. and Pseudoterranova sp.
Although SASLs 1 and 2 died during
anesthesia, postmortem findings indicate
that moderate to severe chronic infections
in the respiratory and renal systems could
have played a role during the anesthesia
(Haulena 2008). Another possibility is an
idiopathic adverse reaction to tiletamine-
zolazepam, a drug combination that has
caused apnea and death in otariids (Dabin
et al. 2002). The most probable cause of
death of SASLs 3 and 4 was pneumonia and
later systemic infection with Gram-positive
and Gram-negative opportunistic bacteria,
one of the most prevalent causes of natural
death in young otariids (Seguel et al. 2011).
Serologic and immunohistochemical find-
ings in SASL 1 and serology in SASL 4
indicate a low reaction to CDV or another
related morbillivirus. In pinnipeds there
have been outbreaks of CDV affecting seals
(Phocidae; Kuiken et al. 2006); however,
we know of no reports of CDV clinical
illness in eared seals (Otariidae). Canine
distemper is a common disease in dogs in
Valdivia (Ernst et al. 1997); thus it is
possible that dogs were the source of
CDV exposure in these SASLs, as has been
suggested in phocids (Kuiken et al. 2006).
In the case of CPV-2, the low antibody
titers (1:8 and 1:64) could represent
previous exposure to or cross-reaction with
an unknown parvovirus.
The serology, histopathology, and im-
munohistochemistry of SASL 1 are indic-
ative of chronic leptospirosis (Gulland
et al. 1996). Clinical leptospirosis is the
second most-common cause of stranding
in California sea lions (Zalophus califor-
nianus) (Greig et al. 2005). To our
F
IGURE
1. Kidney photomicrograph from a South American sea lion (Otaria byronia), SASL 1. There are
occasional aggregates of Leptospira sp. spirochetes within a renal tubule (arrow), and occasional macrophages
that surround the affected tubule contain a large amount of partially degraded Leptospira sp. antigen (arrow
head). Immunohistochemistry for Leptospira sp. antigen counterstained with hematoxylin. Bar 525 mm.
LETTERS 281
knowledge this is the first report of L.
interrogans infection in SASLs.
The presence of T. gondii antibodies
suggests contamination of the river water
with cat feces (Miller et al. 2002). This
would not be surprising given the high (up
to 30%) prevalence of T. gondii in cats in
Valdivia (Ovalle et al. 2000). Toxoplasma
gondii antibody prevalence of up to 40%
has been found in California sea lions, and
there are some reports of encephalitis and
disseminated infection in otariids (re-
viewed in Dubey et al. 2003).
We have shown that SASLs are exposed
to domestic animal shared pathogens
(CDV, CPV-2, T. gondii) and are infected
with agents that can represent zoonotic
risk (L. interrogans,Contracaecum sp.,
Pseudoterranova sp., and Diphyllobotrium
sp.). This highlights the potential use of
marine mammals as animal and human
health sentinels in an urban environment.
We thank L. Huckstad, L. Osman, and
C. Valencia for help during captures.
Technical and financial support was pro-
vided by E. Paredes and J. Saliki. Funding
was provided by the DID-Universidad
Austral de Chile. M.A.S. was funded by a
CONICYT FB 0002 (2014) and a FON-
DECYT no. 3140538. C.V. was funded
by FONDECYT no. 11130305. This work
was conducted with permission from the
subsecretary of Fisheries (SUBPESCA).
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282 JOURNAL OF WILDLIFE DISEASES, VOL. 51, NO. 1, JANUARY 2015
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... [43]. It is also believed that contact with urban animals (dogs, cats, and rats) favors the sharing of pathogens, and they can be infected by diseases with zoonotic potential [44]. It is also noteworthy that these bacteria grow in salt water, and it is possible that the source of coastal species infection could be land-based effluents [5]. ...
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... In pinnipeds, and specifically otariids (eared seals), T. gondii infection and clinical toxoplasmosis are reported in free-ranging populations worldwide (Jensen et al., 2012;Carlson-Bremer et al., 2015;Sepulveda et al., 2015;Michael et al., 2016). Dependent on serological method and selected cut-off value, seroprevalence can exceed 50% (Jensen et al., 2012). ...
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Article available at: https://rdcu.be/cyyOW In 2017, an adult male South American sea lion (Otaria byronia), presenting emaciation and a cervical abscess, stranded alive in Florianópolis, southern Brazil. The animal was directed to a rehabilitation center, dying a few days later. On necropsy, the main gross fndings were necrotizing lymphadenitis of the right prescapular lymph node and nodular bronchopneumo- nia. A novel alphaherpesvirus, tentatively named Otariid alphaherpesvirus 1, was amplifed in several tissue samples. No histopathologic fndings associated with viral infection were observed. Additionally, pulmonary tuberculosis by Mycobac- terium pinnipedii was diagnosed by histopathological, immunohistochemical, and molecular techniques. Several bacteria were cultured from antemortem and postmortem samples, including Proteus mirabilis from the cervical abscess and cardiac blood, and Escherichia coli from the cervical abscess and pericardial efusion. Flavivirus, morbillivirus, and Apicomplexa were not detected by molecular techniques. Herein, we report a novel alphaherpesvirus in a pinniped species of the family Otariidae. Although previously described in Southern Hemisphere pinniped species, including South American sea lions, there is limited information regarding M. pinnipedii impact over this group. Further research is required to determine the associated pathogenesis of this novel herpesvirus, and prevalence of Otariid alphaherpesvirus 1 and M. pinnipedii in the reproductive colonies.
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... Several reports of anti-T. gondii antibodies have been recently identified in Chilean wild mammals, such as southern river otter (Lontra provocax), güiña (Leopardus guigna), American mink (Neovison vison), marine otter (Lontra felina), and southern sea lion (Otaria flavecens) (Sepúlveda et al., 2011(Sepúlveda et al., , 2015Barros et al., 2018;Calvo-Mac et al., 2020). However, the only study on Zoo mammals to date was published 35 years ago (Gorman et al., 1986). ...
Serological prevalence and risk factors of Toxoplasma gondii in Zoo Mammals in Chile
Article
Toxoplasma gondii is a zoonotic cosmopolitan protozoan that causes a high mortality rate among zoo mammals such as New World primates, meerkats, marsupials and Pallas’ cat. It has been recently reported in Chile, mainly among wild populations, but also as the cause of death of a kangaroo and a mara. However, there has not been a T. gondii report at a Zoo population level in Chile in the last 35 years. The aim of the study was to estimate the seroprevalence and risk factors associated with T. gondii infection in mammals housed in a zoo located in the Metropolitan Region of Chile between 2011 and 2018. In this study, we analyzed 350 samples, from 324 animals, belonging to 57 species of carnivores, non-human primates, macropodids, ungulates and rodents to detect the presence of anti-T. gondii antibodies. Additionally, 20 animals were longitudinally sampled to evaluate intra-zoo infection. Using a commercial indirect Enzyme-Linked Immuno Sorbent Assay (ELISA) test, we detected T. gondii antibodies in 72 (22.2 %) samples. The overall seroprevalence estimates were 48.4% in felines, 22.9% in non-feline carnivores, 21.1% in ungulates and 15.0% in non-human primates. There were no positive samples from rodents or marsupials. Of animals sampled longitudinally, only a culpeo fox (Lycalopex cualpaeus) became seropositive along the study indicating exposition inside the facility. T. gondii seroprevalence differed significantly in taxonomic groups (p = 0.003), felines are statistically different from non-feline carnivores (NFC) (p = 0.040), ungulate (p = 0.027) and non-human primates (NHP) (p = 0.009). Annual prevalence comparison was performed showing no statistical difference (p = 0.941). A multivariable logistic regression was performed to ascertain the effect of taxonomic groups, proximity to water sources, diet, sex and type of housing on seropositivity. Only taxonomic group was statistically significant, indicating that NFC (OR = 0.35; 95% CI = 0.15 – 0.83; p = 0.017), ungulates (OR = 0.30; 95% CI = 0.13 – 0.69; p = 0.005), and NHP (OR = 0.25; 95% CI = 0.09 – 0.72; p = 0.010) have lower risk of positivity to T. gondii compared to felines. Additionally, a black-faced spider monkey (Ateles chamek) and a siamang (Symphalangus syndactylus) were seropositive, being the first description of T. gondii infection in these species worldwide. As seen in previous studies, the widespread presence and exposure of T. gondii in zoo mammals was confirmed, and there may be contact with the agent and transmission within the zoo, which was confirmed by one animal became seropositive over the time. This fact could be a health problem for animals susceptible to fatal toxoplasmosis.
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... The source of infection was not determined but was suspected to be introduced terrestrial mammals. Transmission of CDV to pinnipeds leads to high mortality (Duignan et al. 2014), while leptospirosis is a significant cause of seasonal mortality in otariids from Alaska, US to Chile (Sepúlveda et al. 2015). For a highly gregarious pinniped such as the GSL that inhabits areas close to humans and introduced fauna, there is a high potential for interspecies transmission of novel pathogens and the emergence of disease. ...
Occurrence of Mycoplasmas in Galapagos Sea Lions (Zalophus wollebaeki) and their Association with Other Respiratory Pathogens
Article
Full-text available
  • Jul 2021
During the 2018 breeding season, an outbreak of respiratory disease occurred among Galapagos sea lions (Zalophus wollebaeki) that inhabit rookeries near urban areas with introduced fauna such as dogs and cats. Several sea lions had nasal discharge and respiratory distress and were in poor body condition. Eighteen sea lions were captured for a general health assessment including collection of blood for serology and nasal discharge for culture and PCR. Samples were analyzed for 15 respiratory pathogens known to infect cats, dogs, and marine mammals. There was no evidence for interspecies pathogen transmission between Galapagos sea lions and domestic animals. Several bacterial pathogens associated with respiratory tract infection in the California sea lion (Zalophus californianus) were isolated. Mycoplasma spp. were identified by PCR in nasal discharge samples but were not the species commonly found in cats and dogs.
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... A few studies have documented the presence of Sarcocystis spp. in wild animals in Chile. Presence of cysts of this parasite has been confirmed in muscle tissues of pudu deer (Pudu puda), guanacos (Lama guanicoe) and sea lions (Otaria byronia) [9][10][11]. However, Sarcocystis has not yet been described in Chilean wild birds. ...
Molecular Characterization of New Haplotype of Genus Sarcocystis in Seabirds from Magdalena Island, Southern Chile
Article
Full-text available
  • Jan 2021
Evidence of sarcocystid infection was investigated in samples of 16 penguins (Spheniscus. magellanicus), four Dominican gulls (Larus dominicanus) and two Chilean skuas (Stercorarius chilensis) found in Madalenas Islands, Chile, in 2017. Samples of skeletal muscle, cardiac muscle and brain from all birds were screened by a pan-sarcocystid nested-PCR targeting a short fragment of the gene encoding the small ribosomal unit (nPCR-18Sa). The only two positive samples by nPCR-18Sa, both from skuas, were tested by a nested-PCR directed to the internal transcribed spacer 1 (nPCR-ITS1), also a pan-sarcocystidae nested-PCR, and to a nested-PCR directed to the B1 gene (nPCR-B1), for the exclusive detection of Toxoplasma gondii. The two nPCR-18Sa-positive samples were nPCR-ITS1-positive and nPCR-B1-negative. The nPCR-ITS1 nucleotide sequences from the two skuas, which were identical to each other, were revealed closely related to homologous sequences of Sarcocystis halieti, species found in seabirds of northern hemisphere. Larger fragments of genes encoding 18S and partial sequences of genes coding for cytochrome oxidase subunit 1 were also analyzed, corroborating ITS1 data. The haplotypes found in the skuas are unprecedent and closely related to species that use birds as the definitive host. Further studies need to be carried out to detect, identify and isolate this parasite to understand the epidemiology of the infection and its impact on the health of marine fauna.
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Patrones de avistamientos y distribución de mamíferos marinos en el litoral centro-sur de Chile
Article
Full-text available
Marine mammals (MM) are key components of marine ecosystems, becoming important predators in them. Its monitoring allows to know the state of its populations and the health of the ecosystem. For this reason, the diversity, abundance and spatial and temporal distribution of MM in the center-south of Chile will be determined. Scientific observers recorded seasonal presence of MM over a year from land and sea platforms (winter-2016 to autumn-2017). Four species of MM were identified with a total of ~12,000 sightings. The most frequent species was the sea lion (LMC, ~99%), then the Chilean dolphin (DCh), and isolated records of southern right whale and blue whale. The greatest sightings of the LMC and larger cetaceans were recorded in summer, while for DCh, it was in autumn. In Cobquecura, the greatest sightings of LMC were registered (>80%). The larger cetaceans were sighted at >1,500 m from the coast and the DCh at <500 m, around the Itata river. At sea, the greatest sightings of LMC were recorded in spring, during the period of fishing activity, as was the record of more sea lions dead. Although the number of MM identified here is not greater than that described for other parts of Chile, should to be consider that three of these species are classified under threat. In addition, here there is one of the most important groups of DCh and LMC in the central-southern Chile, exposed to important operational interactions with the fisheries. This makes necessary to promptly establish coastal protection measures to ensure the conservation of these marine mammals in central-southern Chile and with it, throughout the Chilean coast.
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Pinnipeds carriers of pathogenic Leptospira: New data based on molecular characterization
Article
Leptospirosis is a bacterial disease caused by the infection of pathogenic strains of the genus Leptospira, endemic in tropical and subtropical regions. Although well documented in terrestrial animals and humans, little information is available on its distribution and impact on marine animals. Despite clinical manifestations that may occur, the occurrence of carriers was suggested in some species. Nevertheless, there are few studies regarding the infection by Leptospira sp. in marine mammals. In this context, and considering the One Health approach, the present aimed to investigate pinnipeds' role as Leptospira sp. carriers. Kidneys of 47 pinnipeds of two species, Arctocephalus australis (n = 40) and Arctocephalus tropicalis (n = 7) were collected. DNA was extracted and the diagnosis was performed through LipL32-PCR and genetic characterization based on secY gene sequencing. Phylogenetic analysis and haplotype networks were constructed. Pathogenic Leptospira sp. DNA was detected in 31.9% (15/47) of the tested pinnipeds. It was possible to amplify and sequence eight strains (6 for A. australis, 2 for A. tropicalis), all identified as L. interrogans, with high similarity with sequences from Icterohaemorrhagiae serogroup. Phylogenetic analysis revealed sequences from the present study grouped in species-specific unique clusters, but very close to others from humans, wild animals, and domestic animals. We demonstrate that pinnipeds could act as carriers, and play an important role in leptospirosis dynamics.
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Geographical Variation of Enteroparasitism in the Southern Sea Lion Otaria flavescens (Shaw, 1800) off the Coast of Chile as Evidenced with Coprological Tests: Implicatons for Zoonotic Risks
Article
  • Jul 2021
The scarce information on the helminth fauna in otariids from the Southeastern Pacific comes mainly from stranded individuals or killed for that purpose. In this study, we compared the abundance and composition of enteroparasitic assemblages of Otaria flavescens using coprological techniques. Three sampling localities from north to south spanning 2,200 km off the Chilean coast were considered (Iquique, Viña del Mar, and Talcahuano). In all, 60 fecal samples were collected, and eggs belonging to 5 taxa were found in 91.6% of the samples. They were the anisakid nematodes Contracaecum and Pseudoterranova, the cestode Adenocephalus (syn. Diphyllobothrium), the trematode Ogmogaster, and the acanthocephalan Corynosoma. Samples from southern Chile (Talcahuano) showed the highest prevalence. Adenocephalus eggs had the highest prevalence and abundance in Iquique and Talcahuano, whereas Ogmogaster was the less prevalent and abundant in all sampling localities. Corynosoma eggs had similar prevalence and abundance among sampling localities, and Pseudoterranova eggs were absent in Iquique and with median prevalence values in Viña del Mar and Talcahuano. Thus, the composition of parasite egg assemblages was different between sampling localities. These differences between sampling localities may help to explain differential records of some zoonotic parasitoses such as pseudoterranovosis and diphyllobothriosis in Peru and Chile, where consumption of raw or marinated fish (ceviche) is common. For example, the lower diversity of parasite egg assemblages in the northern Chilean coast may be due to the absence or lower abundance of first intermediate/paratenic hosts of Pseudoterranova.
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A Decade of Live California Sea Lion ( Zalophus californianus ) Strandings Along the Central California Coast: Causes and Trends, 1991-2000
Article
Full-text available
  • Jan 2005
Stranded marine mammals offer a unique sample of relatively inaccessible wild animals that are more likely to represent the diseased segment of the population and are easy to examine thoroughly. Examination of these animals, therefore, offers a method to detect novel diseases in free-living aquatic mammals. Diseases in marine mammals may reflect environmental changes such as ocean pollution, prey shifts, and global warming. To detect spatial and temporal trends in prevalence of such diseases, we reviewed records for 3,707 California sea lions (Zalophus californianus) that stranded live between 1991 and 2000 along the central California coast. Reasons for stranding were determined from a combination of clinical examinations, hematology and serum biochemistry , radiography, gross necropsy, histopathology, microbiology, and biotoxin assays. Over the ten years, 74% of sea lions stranded in Santa Cruz, Monterey and San Luis Obispo Counties, and 83% of these were admitted between May and October each year. Malnutrition was the most common reason for stranding (32%), followed by leptospi-rosis (27%), trauma (18%), domoic acid intoxication (9%), and cancer (3%). Strandings caused by malnutrition were greatest during the El Niño events of 1992, 1993, and 1998, while strandings caused by leptospirosis accounted for over 60% of strandings in 1991, 1995, and 1999. Although domoic acid was first reported in California sea lions in 1998, there was a small stranding event in 1992 that, based on clinical examinations and his-topathology, was probably also caused by domoic acid. The observed prevalence of cancer among stranded animals remained constant over the past ten years at 3%.
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Ogmogaster heptalineatus n.sp. (Trematoda: Notocotylidae) from the Chilean sea lion Otaria flavescens
Article
Full-text available
  • Sep 1983
Ogmogaster heptalineatus n.sp. is described from the Chilean sea lion Otaria flavescens. Distinct characteristics of the species are: presence of 7 longitudinal ridges on the ventral surface, cirrus armed with scales, testes and ovary deeply lobed and eggs circular with short polar filaments. This is the first report of the genus Ogmogaster from South America and the first report of Otaria flavescens as a host for this genus. ac]19820320
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Pathological Findings in South American Fur Seal Pups (Arctocephalus australis gracilis) found Dead at Guafo Island, Chile
Article
Full-text available
  • Mar 2011
During four breeding seasons (2004-2008), 78 necropsy examinations were performed on South American fur seal pups (Arctocephalus australis gracilis) found dead on Guafo Island, southern Chile (43°36'S, 74°43'W). Tissue samples from 65 pups were examined microscopically. The primary causes of death were enteritis with microscopical lesions of bacteraemia (28.2%), starvation (23.1%), drowning (21.8%), trauma (19.2%) and stillbirth (2.6%). Those pups with enteritis and microscopical lesions of bacteraemia had haemorrhagic enteritis (100%), interstitial pneumonia (86%), periportal hepatitis (73%) and vasculitis (18%). The pups that died from starvation had atrophy of hepatocytes (61%) and cholestasis (61%). The pups that drowned had bronchoalveolar oedema (65%) and foreign bodies in the airways (65%). In animals that died from trauma, the main lesions were skull fractures (67%). This range of pathological findings is within what would be expected in a healthy otariid breeding colony. http://www.sciencedirect.com/science/article/pii/S0021997511000090
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Molecular identification of the Diphyllobothrium species causing diphyllobothriasis in Chilean patients
Article
Full-text available
Diphyllobothriasis caused by the infection of adult Diphyllobothrium tapeworms sporadically occurs in Chile. The occurrence of the disease is closely linked to the consumption of raw or undercooked freshwater and marine fishes. Diagnosis of diphyllobothriasis has been based on laboratory examinations of the morphological characteristics of proglottids and eggs passed in the feces. Although determination of the parasite to the species level is possible through histologic examination of proglottid specimens, the parasites of patients who only discharge eggs cannot be diagnosed to the species level. Determining the species responsible for the infection of humans and other animals in affected areas is an important component of understanding the epidemiologic and enzootic characteristics of any infectious disease. We therefore compared the classification results obtained using a molecular approach with those obtained from morphological and histopathological examination of proglottids or eggs from five Chilean individuals with diphyllobothriasis. DNA analysis confirmed that the causative Diphyllobothrium species in Chile were first identified as Diphyllobothrium latum and Diphyllobothrium pacificum at least. Furthermore, mitochondrial cytochrome c oxidase subunit 1 gene analysis also supported the hypothesis that D. latum from Chile originated from Europe.
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Leptospirosis in California sea lions (Zalophus californianus) stranded along the central California coast, 1981-1994
Article
Full-text available
  • Nov 1996
Prevalence of leptospirosis was determined in California sea lions (Zalophus californianus) stranded live along the central California (USA) coast between January 1981 and December 1994. Clinical signs of renal disease were seen in 764 (33%) of 2338 animals examined; 545 (71%) of these 764 animals died, with similar gross lesions of nephritis. In silver impregnation stains of sections of formalin-fixed kidney, numerous loosely coiled spiral organisms were observed. Leptospira pomona kenniwicki was cultured from four kidney samples in 1991. Epizootics of leptospirosis occurred in 1984, 1988, 1991, and 1994, and were more common in the autumn, typically affecting juvenile males. In 1991 and 1994, 47 animals sampled had antibody titers to L. pomona greater than 1:3200. In 1992, 20 animals sampled were seronegative, and in 1993 three of 20 animals sampled had low titers to L. pomona.
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Crocodilians (Crocodiles, Alligators, Caimans, Gharial)
Chapter
  • Apr 2008
Introduction Physiology and Anatomy Restraint Techniques Drug Delivery Monitoring Analgesia Sedatives Local Anesthetics Immobilizing Drugs Opioids Dissociative Anesthetics Barbiturates α-2 Adrenergic Agonists Other Injectable Agents Inhalant Anesthesia Anesthetic Protocols References
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Fatal cetacean morbillivirus infection in an Australian offshore bottlenose dolphin (Tursiops truncatus)
Article
A juvenile offshore bottlenose dolphin (Tursiops truncatus) was found stranded with neurological signs and unable to swim or float unassisted. It subsequently died, succumbing to a combination of severe pneumonia and encephalitis. Morbillivirus serum neutralisation test serology was positive (titre 1:16) for cetacean morbillivirus and negative for both phocine distemper virus and canine distemper virus. There was concurrent thymic and lymph node lymphoid depletion and necrosis, together with intranuclear and intracytoplasmic acidophilic viral inclusion bodies and multinucleate syncytia within multiple organs. Paramyxovirus capsids were identified in lung sections via electron microscopy and morbillivirus antigen was demonstrated within sections of lung, thymus and brain by immunohistochemistry. Reverse transcription-polymerase chain reaction for morbillivirus nucleoprotein (N) and phosphoprotein (P) genes were positive and phylogenetic gene product sequence analysis revealed 98% and 94% sequence identity to dolphin morbillivirus, respectively. To the authors' knowledge, this is the first report of a cetacean mortality due to morbillivirus infection occurring in the southern hemisphere. Morbillivirus infection should be included in the differential diagnosis of stranded live or dead cetaceans in Australian waters, particularly if animals display neurological signs.
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