Maureen Murray

Anticoagulant Rodenticide Exposure and Toxicosis in Four Species of Birds of Prey Presented to a Wildlife Clinic in Massachusetts, 2006–2010

Abstract Mortalities among birds of prey from anticoagulant rodenticide (AR) toxicosis have been documented in several countries. Reports on extent of exposure within regions of the United States are limited. This study investigated AR exposure and toxicosis in four species of birds of prey (red-tailed hawks [Buteo jamaicensis], barred owls [Strix varia], eastern screech owls [Megascops asio] and great horned owls [Bubo virginianus]) presented to a wildlife clinic in Massachusetts. The aims of this study are to document the proportion of these four species that died or were euthanized due to their presenting injuries that had detectable amounts of ARs in liver tissue; to identify and quantify ARs present; to describe clinical, postmortem, and histopathologic signs of toxicosis; to evaluate potential sublethal effects of AR exposure; and to associate liver AR level with toxicosis. Birds included in the study were sampled without regard to signs of AR toxicosis. Postmortem examinations were conducted, and liver samples were analyzed for AR residues. Of 161 birds tested, 86% had AR residues in liver tissue. The second-generation AR (SGAR) brodifacoum was identified in 99% of positive birds. Mortality from AR toxicosis was diagnosed in 6% of birds. No indications of sublethal effects of exposure were found, and no association between liver brodifacoum level and signs of toxicosis was apparent. Given the high proportion of birds in this study exposed to ARs, specifically brodifacoum, continued monitoring is warranted as new U.S. Environmental Protection Agency regulations on the sale and use of SGARs are enacted.

Diagnosis and Treatment of Secondary Anticoagulant Rodenticide Toxicosis in a Red-tailed Hawk (Buteo jamaicensis)

ABSTRACT Anticoagulant rodenticides inhibit the activation of vitamin K–dependent clotting factors, resulting in fatal hemorrhage. Nontarget species are exposed to these rodenticides primarily by direct consumption of baits or secondarily by consumption of poisoned prey. The diagnosis of anticoagulant rodenticide toxicosis is more challenging in birds than in mammals because of the limited availability of laboratory tests to evaluate avian coagulation. In addition, the presenting signs in birds may differ from those commonly seen in mammals. Treatment for acute blood loss and therapy with vitamin K1 can result in a favorable outcome in birds. This report describes the presenting signs, diagnosis, and successful treatment of a red-tailed hawk (Buteo jamaicensis) with secondary anticoagulant rodenticide toxicosis.

Sepsis and disseminated intravascular coagulation in an eastern spiny softshell turtle (Apalone spinifera spinifera) with acute mycobacteriosis.

Abstract An adult, captive eastern spiny softshell turtle (Apalone spinifera spinifera) was examined for a 4-day history of lethargy and plastron discoloration. The turtle was obtunded and had pale mucous membranes, hemorrhagic nasal discharge, and petechiae on all limbs. The turtle was euthanized due to its grave condition. Necropsy revealed hemorrhagic coelomic effusion, petechiae on the serosal surfaces of the intestinal tract, and bilaterally hemorrhagic lungs. Histologic examination revealed numerous emboli of bacteria associated with fibrinocellular thrombi throughout the blood vessels of multiple tissues. The bacteria in the thrombi were slender bacilli that stained intensely acid fast. Culture of the coelomic fluid yielded Mycobacterium chelonae. Although mycobacteriosis in reptiles is typically a chronic, granulomatous disease, this case demonstrates that mycobacteriosis should be considered in reptiles presenting with acute, nongranulomatous disease. This case also describes clinically apparent hemorrhage due to disseminated intravascular coagulation, which is rarely described in chelonians.

From wetland specialist to hand-fed generalist: shifts in diet and condition with provisioning for a recently urbanized wading bird

Many wildlife species shift their diets to use novel resources in urban areas. The consequences of these shifts are not well known, and consumption of reliable—but low quality—anthropogenic food may present important trade-offs for wildlife health. This may be especially true for carnivorous species such as the American white ibis (Eudocimus albus), a nomadic wading bird which has been increasingly observed in urban parks in South Florida, USA. We tested the effects of anthropogenic provisioning on consumer nutrition (i.e. dietary protein), body condition and ectoparasite burdens along an urban gradient using stable isotope analysis, scaled mass index values and GPS transmitter data. Ibises that assimilated more provisioned food were captured at more urban sites, used more urban habitat, had lower mass–length residuals, lower ectoparasite scores, assimilated less δ15N and had smaller dietary isotopic ellipses. Our results suggest that ibises in urban areas are heavily provisioned with anthropogenic food, which appears to offer a trade-off by providing low-quality, but easily accessible, calories that may not support high mass but may increase time available for anti-parasite behaviours such as preening. Understanding such trade-offs is important for investigating the effects of provisioning on infection risk and the conservation of wildlife in human-modified habitats. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.

Beyond the raccoon roundworm: The natural history of non-raccoon Baylisascaris species in the New World

A total of 10 species of Baylisascaris, a genus of ascaridoid nematodes, occur worldwide and 6 of them occur in the New World. Most of the Baylisascaris species have a similar life cycle with carnivorous mammals or marsupials serving as definitive hosts and a smaller prey host serving as paratenic (or intermediate) hosts. However, one species in rodents is unique in that it only has one host. Considerable research has been conducted on B. procyonis, the raccoon roundworm, as it is a well-known cause of severe to fatal neurologic disease in humans and many wildlife species. However, other Baylisascaris species could cause larva migrans but research on them is limited in comparison. In addition to concerns related to the potential impacts of larva migrans on potential paratenic hosts, there are many questions about the geographic ranges, definitive and paratenic host diversity, and general ecology of these non-raccoon Baylisascaris species. Here, we provide a comprehensive review of the current knowledge of New World Baylisascaris species, including B. columnaris of skunks, B. transfuga and B. venezuelensis of bears, B. laevis of sciurids, B. devosi of gulonids, B. melis of badgers, and B. potosis of kinkajou. Discussed are what is known regarding the morphology, host range, geographic distribution, ecoepidemiology, infection dynamics in definitive and paratenic hosts, treatment, and control of these under-studied species. Also, we discuss the currently used molecular tools used to investigate this group of parasites. Because of morphologic similarities among larval stages of sympatric Baylisascaris species, these molecular tools should provide critical insight into these poorly-understood areas, especially paratenic and definitive host diversity and the possible risk these parasites pose to the health to the former group. This, paired with traditional experimental infections, morphological analysis, and field surveys will lead to a greater understanding of this interesting and important nematode genus.

A Technique for Evisceration as an Alternative to Enucleation in Birds of Prey: 19 Cases

Abstract: Ocular trauma is common in birds of prey presented to wildlife clinics and rehabilitation centers. Enucleation is the procedure most commonly described for treatment of end-stage ocular disease or chronically painful eyes in birds; however, there are several disadvantages and risks to this procedure. While evisceration has been suggested as an alternative, it has not been described for multiple cases or with long-term follow-up data in birds of prey. This report details an evisceration technique performed in 5 captive birds of prey of 4 different species (1 eastern screech owl [Megascops asio], 1 great horned owl [Bubo virginianus], 2 red-tailed hawks [Buteo jamaicensis], and 1 bald eagle [Haliaeetus leucocephalus]) with long-term follow-up information. In addition, this report describes 14 cases of free-living owls of 3 different species (1 great horned owl, 4 barred owls [Strix varia], and 9 eastern screech owls) on which this technique was performed from 2004 to 2011 and which were subsequently released to the wild. Because of the limited risk of complications and the less-severe disruption of facial symmetry, which may be particularly important in owls that are candidates for release to the wild, evisceration should be considered over enucleation in birds of prey that require surgical intervention for the management of severe sequelae to ocular trauma.

Use of anticoagulant rodenticides by pest management professionals in Massachusetts, USA

Secondary exposure to chemical rodenticides, specifically second-generation anticoagulant rodenticides (SGARs), poses a threat to non-target wildlife including birds of prey. Federal regulations in the United States currently limit homeowner access to SGARs as a way of minimizing this threat. With legal access to SGARs, pest management professionals (PMPs) represent a potential linkage to non-target exposure. There is limited research focused on rodent control practices, chemical rodenticide preferences, level of concern and awareness, or opinions on rodenticide regulations as they relate to PMPs. An online survey was sent to PMP companies across Massachusetts, USA, between October and November 2015. Thirty-five responses were obtained, a 20 % response rate. The preferred rodent control method among responding PMP companies was chemical rodenticides, specifically the SGAR bromadiolone. Respondents varied in their level of concern regarding the impact of chemical rodenticides on non-target species and showed a low level of awareness regarding SGAR potency and half-life. All responding companies reported using integrated pest management (IPM) strategies, with nearly all utilizing chemical rodenticides at some point. Enhanced education focused on SGAR potency, bioaccumulation potential, exposure routes, and negative impacts on non-target wildlife may improve efforts made by PMPs to minimize risk to wildlife and decrease dependence on chemical rodenticide use. Future studies evaluating use of anticoagulant rodenticide (ARs) by PMPs and the association with AR residues found in non-target wildlife is necessary to determine if current EPA regulations need to be modified to effectively reduce the risk of SGARs to non-target wildlife.

Anticoagulant rodenticide exposure and toxicosis in four species of birds of prey in Massachusetts, USA, 2012–2016, in relation to use of rodenticides by pest management professionals

Restrictions on second-generation anticoagulant rodenticides (SGARs) in the United States, which were partially implemented in 2011, prohibit the sale of SGAR products through general consumer outlets to minimize use by non-professional or non-agricultural applicators. This study analyzed liver tissue from four species of birds of prey admitted to a wildlife clinic in Massachusetts, USA, from 2012–2016 for residues of anticoagulant rodenticides (ARs). Ninety-four birds were analyzed; 16 were symptomatic for AR toxicosis, and 78 asymptomatic. Ninety-six percent of all birds tested were positive for SGARs: 100% of those diagnosed with AR toxicosis ante-mortem and/or post-mortem and 95% of subclinically exposed birds. Brodifacoum was found in 95% of all birds. Sixty-six percent of all birds contained residues of two or more SGARs. A significant increase in exposures to multiple SGARs occurred in later years in the study. Pesticide use reports (PURs) filed with the Massachusetts Department of Agricultural Resources were reviewed to determine the frequency of use of different ARs by pest management professionals (PMPs) across five years. This study finds that the three SGARs favored by PMPs—bromadiolone, difethialone, brodifacoum—were present in combination in the majority of birds, with increases in multiple exposures driven by increased detections of bromadiolone and difethialone. Continued monitoring of AR residues in nontarget species following full implementation of sales and packaging restrictions in the US is needed in order to elucidate the role of PMP use of SGARs in wildlife exposures and to evaluate the effectiveness of current mitigation measures.

ASSESSMENT OF HEMOGLOBIN BINDING PROTEIN IN LOGGERHEAD SEA TURTLES (CARETTA CARETTA) UNDERGOING REHABILITATION

Abstract:  The acute phase response is an important component of the early reaction of the immune system to insults including infection, inflammation, trauma, neoplasia, and stress. Acute phase proteins are valuable prognostic indicators in many mammalian species but have been poorly studied in reptiles thus far. This study examined 18 paired samples from loggerhead sea turtles (Caretta caretta) for changes observed during the rehabilitation period. Analyses performed included packed cell volume (PCV), hemoglobin binding protein, and plasma protein electrophoresis. Significant differences were observed in all of the protein electrophoresis values. Notably, the concentration of hemoglobin binding protein (as determined by a haptoglobin assay) increased in conjunction with rising total protein (by refractometry) and PCV. The results indicate that this assay may have the potential to be a useful tool in assessing the health of sea turtles.

Ante-mortem and Post-mortem Signs of Anticoagulant Rodenticide Toxicosis in Birds of Prey

Exposure to anticoagulant rodenticides (ARs) in birds of prey is widespread. Interpreting the significance of AR residues in tissue samples recovered from birds in field settings can be challenging for a variety of reasons, including uncertainty regarding the relevance of necropsy findings and the importance of residue levels in the absence of signs of poisoning. A thorough understanding of the pathophysiology of AR toxicosis is useful in evaluating the risks and effects of these toxicants on individual birds and populations. Knowledge of the pathophysiology also aids in recognizing ante-mortem and post-mortem signs of toxicosis. This chapter draws on ante-mortem and post-mortem observations from free-living birds of prey presented to a wildlife hospital to detail signs of poisoning and relates these clinical cases to published literature on AR toxicosis in birds of prey in both field and laboratory settings. Common difficulties in diagnosing AR toxicosis, such as differentiating hemorrhage resulting from poisoning as opposed to traumatic injury, are discussed. Current evidence regarding potential sub-lethal effects of ARs is reviewed. Several case studies that illustrate ante-mortem signs, clinical findings, and post-mortem signs in free-living birds diagnosed with AR toxicosis are presented.