Rehab, Research, and Pathology Abstracts
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Pathological findings in seabirds exposed to crude oil following the 2022 oil spill off the coast of Ventanilla in Lima, Peru Talia Trahtemberg Universidad Peruana Cayetano Heredia (UPCH) Full Abstract
On January 15, 2022, 436,632 gallons of crude oil spilled offshore in Ventanilla, Lima, Peru. Following this event, academic institutions began working in collaboration with local authorities of Servicio Nacional de Áreas Naturales Protegidas (SERNANP) to determine level of impact to wildlife in the surrounding protected areas. Between the second and thirteenth week after the oil spill, 49 dead-on-site seabirds with no external signs of oiling were collected from the main breeding colony affected (Islotes del Grupo Pescadores). Of the 49 birds, 16 were Peruvian boobies (Sula variegata) and 33 were Guanay cormorants (Leucocarbo bougainvilliorum). Carcasses were delivered to specialized veterinary laboratories in Universidad Peruana Cayetano Heredia for the determination of cause-of-death. Necropsies were performed within 24 hours of estimated time of death. Most common gross pathological findings were: tissue congestion, edema, inflammation, and organ enlargement, affecting multiple vital organs such as liver, lungs, brain, heart, kidneys, and spleen. Additionally, some frequent histopathological findings were hemorrhage, necrosis, hemosiderosis, splenic lymphocyte depletion, and encephalitis with type II Alzheimer´s astrocytosis. A significant number of individuals showed a repetitive pattern of lesions consisting of myocarditis, hepatitis, spleen lymphocyte depletion and encephalitis with type II Alzheimer’s astrocytosis which can be explained as a hepatic encephalopathy secondary to toxicant-associated liver damage. Other listed lesions are consistent with findings previously reported following past oil-spill events in seabirds. |
Prevalence Incidence and Characterization of Dermal Lesions in Diving Birds Undergoing Rehabilitation Rebecca Duerr International Bird Rescue Full Abstract
Diving birds affected by oil spills often have toe, foot, hock, and keel lesions, any of which may lead to euthanasia in substantial proportions of affected birds. In an effort to better understand the nature of these injuries, Western Grebes, Clark’s Grebes, Eared Grebes, and Surf Scoters were enrolled in a study to characterize the lesions both grossly and microscopically. The study aimed to ascertain whether these lesions form during care or are present at admission, and to determine whether the severity of lesions provides a predictor of death or successful release. The study also aimed to create a baseline against which future interventional studies can be compared. One hundred thirty-one birds were enrolled in the study, including 74 oiled and 57 non-oiled birds. Salient findings included that a large proportion of oiled and non-oiled birds arrive into care with lesions already present; most birds without lesions at admission do not develop them in care and lesions that do develop are relatively mild; lesion severity and overall lesion burden are not significantly related to survival through rehabilitation; oiled birds take longer to become waterproof than non-oiled birds, and keel lesions are 4.4 times more likely in oiled WEGR than in non-oiled WEGR. In relating clinical assessment to histologic findings, ante-mortem assessment was effective at identifying moderate to severe lesions but under-identified tissue injury deep to normal-appearing skin. This may be partly responsible for the long-held assumption that these lesions are captivity-induced, where our data shows that many lesions are extant at capture and become more apparent as days in care pass. |
25 years of southern sea otter necropsies and research in California:
Knowledge gained to optimize spill response, clinical care, and population recovery Francesca Batac California Department of Fish and Wildlife Full Abstract
Southern sea otters (Enhydra lutris nereis) are a federally-listed threatened species whose population is ~3,000 individuals concentrated along the central California coast. Due to their small population size, restricted geographic range, lack of an insulating blubber layer, and reliance on extremely dense fur to stay warm in cold Pacific waters, southern sea otters are extremely vulnerable to oil spills. The California Department of Fish and Wildlife (CDFW) initiated live and dead sea otter monitoring programs in 1968. Since 1997 CDFW has had a veterinary pathology program dedicated to detailed evaluation of causes of sea otter mortality, and a broadly collaborative sea otter research and student mentorship program. During the past 25 years more than 5,500 otters have been examined by biologists and pathologists, nearly 2 times the current southern sea otter population. Health concerns identified through necropsies have been further investigated via interdisciplinary research. The products of this collaborative effort have improved clinical care for stranded sea otters, and highlighted connections with human activity for common sea otter diseases caused by land-based pathogens and harmful algal blooms. We have identified health threats that could impair sea otter population recovery and documented shifting disease patterns through time. We investigated mass-mortality events and discovered previously undocumented pathogens and diseases. Much of this work has been published, including information on optimal care of oiled wildlife and conditions that could be confused with oil exposure. We review these discoveries and highlight how they can inform clinical care, population recovery, and oil spill response efforts now and into the future. |
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Reducing stress during wash: a lesson in chemical sedation
Readiness for Global Oil Spills Kylie Clatterbuck Rebecca Duerr Tri State Bird Rescue and Research, Inc International Bird Rescue Full Abstract
The wash process for plumage-contaminated wild birds, such as those affected by oil spills, can be lengthy and complex. It involves manual restraint, manipulation of all body parts, and birds often react in ways that suggest they are undergoing extreme stress such as increased vocalization and physically struggling. Oftentimes the animals' behaviors during the wash process can lead to secondary injuries, unnecessary expenditure of valuable energy, and, in some extreme cases even death. Due to the difficulty of conducting research during an active spill response, nothing has been published about the outcomes of using chemical sedation during the wash process. Utilizing the regular admittance of oiled and contaminated birds into our regular rehabilitation programs, International Bird Rescue (IBR) and Tri-State Bird Rescue & Research (TSBRR) conducted a study weighing the benefits and risks of chemical sedation with reversal for wash with the aim of decreasing the bird's overall stress and to limit the chances of injury during wash. This presentation will go over the results of this collaborative study including methods, response to sedation, post reversal behaviors, and overall survivability post wash. This study also highlighted thermoregulatory issues and needs for additional heat support during the drying process. We will explain the benefits of chemical sedation with reversal during wash and how it can be a tool for organizations who deal with contaminated wildlife. |
Nutritional Needs of Oiled Wild Birds Rebecca Duerr International Bird Rescue Full Abstract
Wild birds that become oiled require specialized care to resolve a multitude of common problems that make their nutritional needs different from typical avian patients in zoologic or private practice circumstances. Immediate problems at admission include hypothermia, anemia, hypoproteinemia, and often severe emaciation, with many birds entering care at 60-80% of normal body weight. Depending on the contaminating product and details of exposure, injuries that may manifest include skin burns, corneal ulcers, gastrointestinal ulceration, respiratory damage, or less obvious toxic effects of the product such as neurologic, cardiovascular, or organ function problems. Recovery from each problem is only possible when animals have the metabolic resources needed to simultaneously mount immune responses and heal damaged tissues. Prior to release, it is also imperative that birds recover normal bodily energetic reserves necessary for resumption of their wild lives. Affected birds are often inappetent initially and may require assistive feedings. On wash day, delivery of adequate nutritional support is complicated by the need to withhold food to lower risks of regurgitation and aspiration during wash. Later, while birds are going in and out of pools to preen and recover their waterproof plumage, time for birds to rest and eat is often lacking. It is not until birds have been washed and have recovered waterproof plumage that they finally are able to be left alone to renourish themselves fully. These challenges result in oiled birds needing large amounts of appropriate food at all stages of care, far above that of typical avian patients seen in zoos or private practice where maintenance nutrition or nutritional problems related to inappropriate diets are the norm. Plentiful, high-quality foods for both assistive feedings and self-feeding are needed to fuel recovery of these patients. |