Fetal distress and in utero pneumonia in perinatal dolphins during the Northern Gulf of Mexico unusual mortality event.

An unusual mortality event (UME) involving primarily common bottlenose dolphins Tursiops truncatus of all size classes stranding along coastal Louisiana, Mississippi, and Alabama, USA, started in early 2010 and continued into 2014. During this northern Gulf of Mexico UME, a distinct cluster of perinatal dolphins (total body length <115 cm) stranded in Mississippi and Alabama during 2011. The proportion of annual dolphin strandings that were perinates between 2009 and 2013 were compared to baseline strandings (2000-2005). A case-reference study was conducted to compare demographics, histologic lesions, and Brucella sp. infection prevalence in 69 UME perinatal dolphins to findings from 26 reference perinates stranded in South Carolina and Florida outside of the UME area. Compared to reference perinates, UME perinates were more likely to have died in utero or very soon after birth (presence of atelectasis in 88 vs. 15%, p < 0.0001), have fetal distress (87 vs. 27%, p < 0.0001), and have pneumonia not associated with lungworm infection (65 vs. 19%, p = 0.0001). The percentage of perinates with Brucella sp. infections identified via lung PCR was higher among UME perinates stranding in Mississippi and Alabama compared to reference perinates (61 vs. 24%, p = 0.01), and multiple different Brucella omp genetic sequences were identified in UME perinates. These results support that from 2011 to 2013, during the northern Gulf of Mexico UME, bottlenose dolphins were particularly susceptible to late-term pregnancy failures and development of in utero infections including brucellosis.

Adrenal Gland and Lung Lesions in Gulf of Mexico Common Bottlenose Dolphins (Tursiops truncatus) Found Dead following the Deepwater Horizon Oil Spill.

A northern Gulf of Mexico (GoM) cetacean unusual mortality event (UME) involving primarily bottlenose dolphins (Tursiops truncatus) in Louisiana, Mississippi, and Alabama began in February 2010 and continued into 2014. Overlapping in time and space with this UME was the Deepwater Horizon (DWH) oil spill, which was proposed as a contributing cause of adrenal disease, lung disease, and poor health in live dolphins examined during 2011 in Barataria Bay, Louisiana. To assess potential contributing factors and causes of deaths for stranded UME dolphins from June 2010 through December 2012, lung and adrenal gland tissues were histologically evaluated from 46 fresh dead non-perinatal carcasses that stranded in Louisiana (including 22 from Barataria Bay), Mississippi, and Alabama. UME dolphins were tested for evidence of biotoxicosis, morbillivirus infection, and brucellosis. Results were compared to up to 106 fresh dead stranded dolphins from outside the UME area or prior to the DWH spill. UME dolphins were more likely to have primary bacterial pneumonia (22% compared to 2% in non-UME dolphins, P = .003) and thin adrenal cortices (33% compared to 7% in non-UME dolphins, P = .003). In 70% of UME dolphins with primary bacterial pneumonia, the condition either caused or contributed significantly to death. Brucellosis and morbillivirus infections were detected in 7% and 11% of UME dolphins, respectively, and biotoxin levels were low or below the detection limit, indicating that these were not primary causes of the current UME. The rare, life-threatening, and chronic adrenal gland and lung diseases identified in stranded UME dolphins are consistent with exposure to petroleum compounds as seen in other mammals. Exposure of dolphins to elevated petroleum compounds present in coastal GoM waters during and after the DWH oil spill is proposed as a cause of adrenal and lung disease and as a contributor to increased dolphin deaths.

Protective role of selenium on aflatoxin b1-induced hepatic dysfunction and apoptosis of liver in ducklings.

Aflatoxin B1 (AFB1) is a mycotoxin which causes toxicity through oxidative damage. Selenium (Se), an antioxidative agent, can antagonize some toxicity induced by oxidative stress. The aim of this work was to investigate the toxicity of AFB1 and the protective effects of Se on duckling liver in vivo. The study consisted of three groups: AFB1, AFB1Tx, and a control group. AFB1 group was administered aflatoxin intragastrically (0.1 mg/kg body weight). AFB1Tx group was administered AFB1 intragastrically (0.1 mg/kg body weight) plus sodium selenite (1 mg/kg body weight). The control group was given the same volume of dimethyl sulfoxide (DMSO) via intragastric intubation. All three groups received daily administrations for 28 days. Blood samples were obtained on the 14th, 21st, and 28th days of post-administration, and the serum alanine aminotransferase (ALT) and aspartate transaminase (AST) were evaluated. A high level of serum ALT and AST was observed in AFB1 group. The activity of ALT and AST was significantly lower in Se treatment group than those in AFB1 group. Liver samples were collected on the 14th, 21st, and 28th days of post-administration, and concentrations of Bcl-2, Bax, caspase-3, and p53 were measured. Increased expression level of Bax, caspase-3, and p53 and decreased Bcl-2 expression level and Bcl-2/Bax ratio were observed in AFB1 group. Se diminished hepatic dysfunction, or damage and modulated the expression of apoptotic related proteins, in a time-dependent manner. In conclusion, concurrent treatment with Se reduced the AFB1-induced hepatic dysfunction and apoptosis.

Bartonella species detection in captive, stranded and free-ranging cetaceans.

We present prevalence of Bartonella spp. for multiple cohorts of wild and captive cetaceans. One hundred and six cetaceans including 86 bottlenose dolphins (71 free-ranging, 14 captive in a facility with a dolphin experiencing debility of unknown origin, 1 stranded), 11 striped dolphins, 4 harbor porpoises, 3 Risso's dolphins, 1 dwarf sperm whale and 1 pygmy sperm whale (all stranded) were sampled. Whole blood (n = 95 live animals) and tissues (n = 15 freshly dead animals) were screened by PCR (n = 106 animals), PCR of enrichment cultures (n = 50 animals), and subcultures (n = 50 animals). Bartonella spp. were detected from 17 cetaceans, including 12 by direct extraction PCR of blood or tissues, 6 by PCR of enrichment cultures, and 4 by subculture isolation. Bartonella spp. were more commonly detected from the captive (6/14, 43%) than from free-ranging (2/71, 2.8%) bottlenose dolphins, and were commonly detected from the stranded animals (9/21, 43%; 3/11 striped dolphins, 3/4 harbor porpoises, 2/3 Risso's dolphins, 1/1 pygmy sperm whale, 0/1 dwarf sperm whale, 0/1 bottlenose dolphin). Sequencing identified a Bartonella spp. most similar to B. henselae San Antonio 2 in eight cases (4 bottlenose dolphins, 2 striped dolphins, 2 harbor porpoises), B. henselae Houston 1 in three cases (2 Risso's dolphins, 1 harbor porpoise), and untyped in six cases (4 bottlenose dolphins, 1 striped dolphin, 1 pygmy sperm whale). Although disease causation has not been established, Bartonella species were detected more commonly from cetaceans that were overtly debilitated or were cohabiting in captivity with a debilitated animal than from free-ranging animals. The detection of Bartonella spp. from cetaceans may be of pathophysiological concern.

Relationship between plasma iron concentration and gastric pH in captive adult bottlenose dolphins (Tursiops truncatus).

OBJECTIVE: To determine the correlation between plasma iron concentrations and gastric pH in a population of captive Atlantic bottlenose dolphins (Tursiops truncatus). ANIMALS: 6 adult female dolphins that ranged from 16 to 30 years of age. PROCEDURES: Blood and gastric samples were collected from each dolphin to allow measurement of plasma iron concentrations and gastric pH, respectively. Samples were collected each month for 12 months. RESULTS: Within each dolphin, plasma iron concentrations and gastric pH did not differ significantly over time. There was a strong negative correlation (r = -0.85) between plasma iron concentration and gastric pH, which suggested that dolphins with a lower gastric pH had a higher plasma iron concentration. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of results reported here suggested that gastric pH may play an important role in iron absorption in dolphins.

Oral administration of sucrose solutions and measurement of serum sucrose concentrations to evaluate gastric permeability in adult bottlenose dolphins (Tursiops truncatus).

OBJECTIVE: To measure concentrations of sucrose in the serum of captive dolphins after oral administration of a sucrose solution and determine the suitability of this method for use as a test to detect gastric ulcers. ANIMALS: 8 adult captive bottlenose dolphins (Tursiops truncatus). PROCEDURES: Blood samples were collected from the ventral fluke vein of dolphins before and 45 minutes after oral administration of 500 mL of solution containing 25 or 50 g of sucrose; oral administration was achieved by use of gastric intubation. Serum was separated, diluted in a solution of 90% acetonitrile-to 10% water that contained 10 ng of an internal standard (trichlormethiazide)/microL, mixed, and centrifuged. Supernatant was analyzed by use of liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS). RESULTS: Serum sucrose concentrations of dolphins were at or less than the limits of detection before oral administration. Values after administration of sucrose solution varied among dolphins and were higher and more variable after administration of 50 g, compared with concentrations after administration of 25 g. CONCLUSIONS AND CLINICAL RELEVANCE: Serum sucrose concentrations in samples collected during routine health evaluations of captive dolphins can be reliably measured by use of LC-MS-MS. Correlating serum sucrose concentrations with endoscopic observations of the gastric mucosa of dolphins will validate this approach for use in screening for the prevalence and severity of gastric ulcers and determining the efficacy of treatment regimens.