49(4), (1 December 2018) https://doi.org/10.1638/2018-0022.1

ANALYSIS OF HISTORICAL MEDICAL RECORDS OF CALIFORNIA CONDORS (GYMNOGYPS CALIFORNIANUS) ADMITTED FOR LEAD EXPOSURE TO THE LOS ANGELES ZOO AND BOTANICAL GARDENS BETWEEN 1997 AND 2012: A CASE SERIES STUDY

Natalie Nguyen, Miguel D. Saggese, and Curtis Eng

Lead toxicosis remains the primary cause of death in wild populations of California condors (Gymnogyps californianus). Many condors require medical intervention with lead chelation therapy, among other conservation measures, to survive in the wild. An analysis of historical medical records of California condors admitted for lead exposure to the Los Angeles Zoo and Botanical Gardens (LA Zoo) between 1997 and 2012 was performed to investigate clinical presentation, radiographic findings, and treatment along with the potential impact of these factors on recovery and successful release back into the wild. Of 100 individual condors presented to the LA Zoo for suspected lead toxicosis during this period, 84 condors had records for initial laboratory blood lead levels. For these 84 condors (40 [47.6%] females and 44 [52.4%] males), 277 initial laboratory blood lead levels in total were recorded because of repeated admissions. Thirty-two (38%) condors were admitted once to the zoo and 62% were admitted two or more times. Clinical signs were not observed in 87.5% of the condors admitted with median blood lead concentrations of 26 μg/dl. Of the radiographs taken on initial presentation, 65% did not show evidence of gastrointestinal metallic foreign bodies. Various treatments protocols with edetatum calcium disodium, dimercaptosuccinic acid, and lactated Ringer's solution were documented in the medical records. Of the 277 admissions, 154 admissions had a recorded outcome posttreatment of which 140 (91%) admissions were released back to the wild. This study contributes to a better understanding of how intervention and therapeutic approaches have been essential for the recovery, release, and sustainability of these birds as a wild population. Consistency in data collection of California condors admitted for diagnosis and treatment of lead toxicosis is needed to better assess the impacts of medical interventions.

 

Introduction:

· California condor – opportunistic scavenger, largest soaring bird in N. America, critically endangered

· In 1985, all remaining (n=23) wild condors brought into captivity to recover species and release

· Now there are >400 condors

· Primary cause of death: lead toxicity

· Other causes: microtrash ingestion, power line collision, gunshot, strychnine, wildlife predation 

· Lead toxicity is chronic – ammunition shatters the condors ingest small amounts with feeding

· *During fall hunting season worse

· Clinical signs only develop when levels are significant  

· Bone accumulates lead over time. Some lead in bone is available to chelation but most is not. Therefore, as bone is slowly remodeled and under times of stress, lead is released back into blood  - this can result in repeated toxicity events

· to mitigate:  feeding stations deployed & condors are checked for lead levels and chelated when necessary 

Diagnosis:

· Blood lead and radiographs

· unexposed (<20 ug/dl); exposed or subclinical (20–59 lg/dl); clinically exposed (60–99 lg/dl); exhibiting acute toxicity (>100 lg/dl)

· Blood lead half life is 13 days, so reflects only ACUTE exposure (can use feather vane lead concentrations or lead isotope ratios to diagnose chronic but this is not commercially available)

· Note: blood lead absorption in GIT is inversely proportional to metal particle size 

Clinical Signs: crop stasis, neurologic signs, behavioral changes, weakness, weight loss, traumatic lesions (more likely with chronic exposure)

Treatment: chelation with CaEDTA and/or DMSA, subcutaneous fluids, supportive care 

· If rads indicate metal FB:  they also feed increased fur or skin to encourage casting or passing of material or add psyllium to encourage passing. They then screen feces radiographically to ensure metal has been passed. If not, will do surgery as mandatory to have no metal FB on rads in order to release

M&M

· Retrospective; Medical records reviewed of 84 California condors with 277 total admissions to LA Zoo for suspected lead toxicity 

Results/discussion:

· No difference in sex (similar percentage)

· Age was NOT associated with initial lead level or outcome but majority of those affected were bw 2-6 yrs

· < 2 yrs old may be at lower risk bc not exploring as far 

· Subadults are mobile and exploring range, are higher ranking socially than younger birds thus consuming carrion first, and may be over-represented in pop’n (thus bias)

· > 6 yrs tend to stay closer to breeding territories

· Authors felt that the LeadCare analyzer overestimated levels in field when compared to lab values

· Must take into account CS and other risk factors when deciding whether to admit to rehab

· Only n=18 birds had CS: crop stasis, neuro signs, behavior changes, weakness, weight loss, trauma 

· Considered for release once blood lead < 35 ug/dl

            

Take-home points: 

· Lead toxicosis is leading cause of death of California condors

· Many (62%) are admitted for treatment at rehab center more than once

· Clinical signs not seen in the majority (87%)

· More than half (65%) do not have GI metallic foreign body on radiograph

· Most (91%) are released after treatment and blood lead levels were not correlated with outcome

· Intervention and treatment has been essential to recovery of this species population

· Important to understand acute v. chronic and the implications for bone and soft tissue to be a source of chronic lead release into blood, even when blood lead levels have decreased and no metal FB present. 

Journal of Avian Medicine and Surgery. 2018 Mar;32(1):34-40.

The Use of Lead Isotope Analysis to Identify Potential Sources of Lead Toxicosis in a Juvenile Bald Eagle (Haliaeetus leucocephalus) With Ventricular Foreign Bodies

Dana Franzen-Klein, David McRuer, Vincent A. Slabe, Todd Katzner

Abstract: A male juvenile bald eagle (Haliaeetus leucocephalus) was admitted to the Wildlife Center of Virginia with a left humeral fracture a large quantity of anthropogenic debris in the ventriculus, a blood lead level of 0.616 ppm, and clinical signs consistent with chronic lead toxicosis. Because of the poor prognosis for recovery and release, the eagle was euthanatized. Lead isotope analysis was performed to identify potential anthropogenic sources of lead in this bird. The lead isotope ratios in the eagle’s femur (0.8773), liver (0.8761), and kidneys (0.8686) were most closely related to lead paint (0.8925), leaded gasoline (0.8450), and zinc smelting (0.8240). The lead isotope ratios were dissimilar to lead ammunition (0.8179) and the anthropogenic debris in the ventriculus. This case report documents foreign body ingestion in a free-ranging bald eagle and demonstrates the clinical utility of lead isotope analysis to potentially identify or exclude anthropogenic sources of lead poisoning in wildlife patients.

Case Report

· Bald eagle presented to wildlife clinic.  Euthanized.

· Clinical signs of chronic lead toxicity

· To determine the lead source, ventricular contents and samples of kidney, liver, femur were sent to the MSU for lead concentration and isotope analysis

· Elevated lead in the femur, liver, and kidney

· Isotope ratios were most closely related to lead paint, leaded gasoline, and zinc smelting

· Isotopes did not appear closely related to ammunition.

Discussion

· Poisoning most common cause of death of carcasses submitted to the National Wildlife Health Center from 1982 to 2013

· Lead poisoning in > 60% of poisoned birds

· The 3 main sources of environmental lead: 

· 1) ammunition

· 2) fishing sinkers and jigs – both via direct ingestion.

· 3) mining and smelting industry

· Indirect: contaminated water, prey, or direct ingestion of man-made objects

· Lead has 4 main isotopes.  Different sources have unique isotope ratios.

· Bone, liver, and kidney levels were several orders of magnitude higher than the blood lead level.

· Blood and soft tissue lead levels reflect recent lead exposure or leaching from bone

· Bone lead levels reflect chronic lead exposure

Take Home: Lead isotope ratios in this bird were dissimilar to lead ammunition, suggesting environmental sources other than ammunition may be contributing to lead poisoning in this species.  Lead has multiple isotopes and test can help reveal to source because different sources have unique isotope ratios.

Journal of Wildlife Diseases, 53(4), 2017, pp. 816–823

INFLUENCE OF SNOWFALL ON BLOOD LEAD LEVELS OF FREE- FLYING BALD EAGLES (HALIAEETUS LEUCOCEPHALUS) IN THE UPPER MISSISSIPPI RIVER VALLEY

Lindblom, Reichart LM, Mandernack BA, Solensky M, Schoenebeck CW, Redig PT

ABSTRACT: Lead poisoning of scavenging raptors occurs primarily via consumption of game animal carcasses containing lead, which peaks during fall firearm hunting seasons. We hypothesized that snowfall would mitigate exposure by concealing carcasses. We categorized blood lead level (BLL) for a subsample of Bald Eagles (Haliaeetus leucocephalus) from the Upper Mississippi River Valley and described BLL with respect to age, sex, and snowfall. We captured Bald Eagles overwintering in the Upper Mississippi River Valley (n=455) between December 1999 and January 2002. Individual BLL ranged from nondetectable to 335 lg/dL, with 73% of the samples testing positive for acute exposure to lead. Eagle BLL did not significantly differ between age or sex, but levels were higher immediately following the hunting season, and they were lower when the previous month’s snowfall was greater than 11 cm. This study suggests a window of time between the white-tailed deer (Odocoileus virginianus) hunting season and the onset of snow when the population experienced peak exposure to lead. Combining these findings with existing research, we offer a narrative of the annual lead exposure cycle of Upper Mississippi River Valley Bald Eagles. These temporal associations are necessary considerations for accurate collection and interpretation of BLL.

 

Introduction

· Elevated lead in the winter or around hunting season

· Snowfall may cover lead-tainted carcasses and decrease lead exposure

· Bald Eagles locate prey by sight

· Half life of blood led level (BLL) is about 2 weeks

M&M:

· 55 BAEA over 3 winter periods from early December to March 1999-2002

· Lead tested by graphite furnace atomic absorption spectrophotometry

· Separated lead into exposure level (<10 ug/dL = absent/background, 10-19 = elevated exposure, 20-59 = subclinical, 60-99= clinical, >100 = acute toxicity)

Results

· 73% of sampled had positive lead exposure

· Most had elevated exposure > background > subclinical > clinical > acute tox

· Highest average lead levels were January > December > March > February

· Higher in early winter during and following the deer hunting season

· No significant difference between sex or age group

· Significantly higher BLL values were associated with little to no snow (<3cm).

· Lower BLL in months with high snow (>11 cm)

Discussion

· Supports hypothesis that snowfall may cover lead carcasses and decrease consumption

· This study had light snow in early winter and heavy snow in the late winter

· Combining with other data, lead-tainted deer are highest in early winter

· Other clinical data showed a rise in BLL in march coinciding with melting snow

· In March, BAEA tend to migrate and consume fish leading to decreased BLL

· Underestimates lead toxicity as only live birds were sampled

Inclusion Body Herpesvirus Hepatitis in Captive Falcons in the Middle East: A Review of Clinical and Pathologic Findings

Raj Raghav, and Jaime Samour

Journal of Avian Medicine and Surgery 33(1):1–6, 2019

Taxonomy: Falconiformes (order) → Falconidae (family) → Falco (genus)

Abstract: Inclusion body hepatitis in falcons is caused by a herpesvirus designated Falconid HV-1. This herpesvirus and other herpesviruses affecting birds of prey have not been assigned to a genus and include inclusion body herpesvirus hepatitis in eagles (Accipitrid HV-1) and inclusion body herpesvirus hepatitis in owls (Strigid HV-1). Herpesvirus infections have been diagnosed in both captive and free-living raptors across Europe, North America, and Asia in different species of the family Falconidae. Herpesviruses affecting owls and falcons have been found to be antigenically similar to pigeon herpesvirus (Columbid HV-1) and distinct from other avian herpesviruses. When the herpesvirus isolates from owls, falcons, and pigeons were compared by sequencing a fragment of the herpes viral DNA polymerase gene from those birds naturally infected with the virus, the sequences from these 3 sources were found to be nearly identical. The authors of this study concluded that the Falconid HV-1, Strigid HV-1, and Columbid HV-1 were the same virus. Furthermore, the authors also proposed that the virus therefore be referred to as Columbid HV-1 (CoHV-1), because pigeons may be responsible for the transmission of the virus to birds of prey. Pigeons are often carriers of the virus without showing any clinical signs. It has long been suspected that raptors may contract the infection by the ingestion of infected pigeons. Some studies have suggested that falcons may not contract the infection through the oral route by ingesting carrier pigeons, but through the ocular or nasal route. Inclusion body herpesvirus hepatitis is a frequently diagnosed disease in the captive falcon population used for falconry, racing, and breeding in the Middle East, and it seems to be associated with the extensive use of pigeons for training and as a food item. This paper reviews the clinical and pathological findings in falcons affected by inclusion body herpesvirus hepatitis in the Middle East.

Introduction:

· Herpesvirus have double-stranded DNA, a linear genome, a protein capsid, and an envelope

· All bird herpesviruses are within subfamily alphaherpesvirinae so far

· CoHV-1 (columbid herpesvirus), Strigid HV-1, and FaHV-1 are closely-related, if not identical viruses

· FaHV-1 (falconid herpesvirus) differs by one gene from CoHV-1

· Clinical signs of these viruses are very similar and 100% fatal to falcons

· Viral replication in the liver (causing hepatitis) and epithelial cells of the intestines and renal tubules

· Destroyed bone marrow preventing an inflammatory response

· Because pigeons are asymptomatic carriers of CoHV-1, contact with pigeons puts raptors at risk for infection

· Route of transmission is possibly ingestion or direct contact

· Do not feed pigeons of unknown herpesvirus status to birds of prey

· Virus has low survivability in the environment

Clinical Diagnosis of Falcons with Inclusion Body Herpes Virus Hepatitis

· Clinical signs: Nonspecific (reduced preening activities, severe depression, anorexia, regurgitation, vomiting, biliverdinuria, sudden death), very rarely CNS → death within 24-72 hours

· Clinical pathology: Anemia, leukopenia, heteropenia, toxic changes, elevated CK, AST and bile acids

· Necropsy findings: Hepatosplenomegaly with small yellow necrotic foci on liver, spleen, intestines, bursa, kidneys, pancreas, and gonads

· Histology: Intranuclear eosinophilic inclusion bodies in cells on the periphery of lesions

· Adenovirus also has large intranuclear inclusions in hepatocytes, but usually adenovirus is basophilic

· Diagnosis: hepatic biopsy with intranuclear eosinophilic inclusion bodies

· Treatment: Supportive care + acyclovir 80 mg/kg PO q8h + quarantine

· Mortality in falcons = 100% despite treatment

· Vaccination: No vaccine for falcons, though viruses are in development can reduce viral excretion of pigeons

Conclusions: FaHV-1 and CoHV-1 are closely related. CoHV-1 is likely infecting raptors when they come in contact with pigeons as a food source, causing causes acute clinical signs and death. No treatment. No vaccine.

Evaluation of Goniometry and Electrogoniometry of Carpus and Elbow Joints in the Barred Owl (Strix varia)

Jenessa L. Gjeltema, Laurel A. Degernes, Halley D. Buckanoff, Denis J. Marcellin-Little

Journal of Avian Medicine and Surgery 32(4):267–278, 2018

Taxonomy: Strigiformes (Order) → Strigidae (family) → Strix (genus)

Abstract: The motion of wing joints is a critical factor for successful flight in avian patients, but little information is available about goniometry in birds. Elbow and carpus joints in flexed and extended positions from 10 orthopedically normal wings of 6 adult wild barred owls (Strix varia) were evaluated with the animals under general anesthesia using a modified universal plastic goniometer and an electrogoniometer. These measurements were compared to those obtained using radiographic assessment. Intra- and interobserver reliability was calculated. Measurements in live animals were compared to those obtained from frozen-thawed carcasses. Results showed that the modified universal plastic goniometer can be used to obtain accurate results for elbow flexion and extension and for carpal flexion with good to excellent reliability compared to measurements collected from radiographic assessment. Measurements obtained using an electrogoniometer were less accurate and less reliable than those obtained with a plastic goniometer, possibly because of the size and configuration of the model used. Comparison of measurements from live animals and carcasses revealed no significant differences between mean measurements and suggested that further evaluation of carcasses as a model for study of goniometry measurements in avian wing joints should be considered.

Background:

· Goniometry is the measurement of ROM of a joint

· Methods: electrogoniometry, universal plastic goniometer, measurement of joints in photos

· Radiographic measurements were used as the gold standard to compare to

· Caution: It is possible to hyperextend joints and affect measurements

Objective: Evaluate the accuracy of a plastic goniometer and electrogoniometer compared to radiographic measurements of the elbow and carpus of healthy barred owls under general anesthesia.

Key Points:

· Plastic goniometer was accurate for elbow flexion and extension and the carpal flexion

· Electrogoniometer was less accurate

Conclusion: Plastic goniometer was the most accurate device to measure ROM of avian wing joints as compared to the gold standard of radiographic measurements. Electrogoniometry was not accurate.

Plastic goniometer ElectrogoniometerRadiographic assessment

Serratospiculosis in Captive Peregrine Falcons (Falco peregrinus) in Switzerland

Ines B. Veiga, Marion Schediwy, Brigitte Hentrich, Caroline F. Frey, Nelson Marreros,

Nadine Stokar-Regenscheit

Journal of Avian Medicine and Surgery 31(3):250–255, 2017

Taxonomy: Falconiformes (order) → Falconidae (family) → Falco (genus)

Abstract: Infection with Serratospiculum species was identified in a captive peregrine falcon (Falco peregrinus) in Switzerland. Pathologic and parasitologic examination results revealed generalized severe granulomatous airsacculitis, with intralesional adults, larvae, and eggs of Serratospiculum species. Subsequently, an individual coprological analysis of the remaining 15 falcons (peregrine falcons and gyrfalcons [Falco rusticolus]) from the same owner was performed. Eggs of Serratospiculum species (4 birds) and Capillaria species (11 birds), and oocysts of Caryospora species (1 bird) were detected. Treatment with ivermection (2 mg/kg SC) was effective, as none of the falcons excreted Serratospiculum species eggs 10 days after one dose. To our knowledge, this is the first report of infection with Serratospiculum species in captive falcons in Europe.

Case: 8yo female peregrine falcon found dead

· Livered in a mixed group of privately owned gyrfalcons and peregrine falcons

· Large number of nematodes found in coelomic cavity, thoracic and abdominal air sacs, despite yearly ivermectin

· Air sacs were thickened and contained granulomas

· Identified Serratospiculum spp. by microscopic examination

· Visceral (pericardium, liver) and renal gout (not a direct effect of nematodes)

· Four birds in the flock were positive on fecal examination and shedding was stopped with ivermectin

Key Points:

· Serratospiculosis affects air sacs in many bird sps, particularly in Falconidae family

· Causes respiratory signs and/or flight intolerance

· Life Cycle: Birds (host) eat infected beetles, grasshoppers, woodlice, locusts (intermediate host) that are parasitized by infective 3rd stage larvae → larvae penetrate proventriculus and gizzard and migrate into the air sacs and lungs where they molt and reach sexual maturity → eggs are regurgitated and swallowed and then released into the environment in feces or pellets

· Anthelmintic drugs with effect against Serratospiculum: fenbendazole, levamisole, mebendazole, moxidectin, thiabendazole, melarsomine + ivermectin, and ivermectin

Conclusions: Serratospiculosis causes respiratory signs in birds and is transmitted by ingestion of infected insects.

CLINICAL EFFECT OF HEMOPARASITE INFECTIONS IN SNOWY OWLS (BUBO SCANDIACUS)

Kendra C. Baker, Christy L. Rettenmund, Samantha J. Sander E. Rivas, Kaitlin C. Green, et. al.

Journal of Zoo and Wildlife Medicine, 49(1):143-152

Abstract:

Vector-borne hemoparasites are commonly found in avian species. Plasmodium spp., the causative agent of avian malaria, are intraerythrocytic parasites that can cause signs ranging from subclinical infection to severe acute disease. In raptor species, most hemoparasites are associated with subclinical infection and are generally not treated when seen on blood evaluation. This case series reviews five cases of hemoparasite infection in snowy owls (Bubo scandiacus). These animals were infected with a variety of hemoparasites, including Plasmodium, Haemoproteus, and Leukocytozoon spp. Death of one of these birds due to hemoparasite burden led to a change in the monitoring for and treatment of subclinical hemoparasitic infections in this species. Three subsequently infected snowy owls have been treated with primaquine and chloroquine. The birds that were treated survived infection, and parasite burdens in peripheral blood diminished. Postulated reasons for increased morbidity and mortality associated with hemoparasitic infections in captive snowy owls, as opposed to other raptor species, include stress, concurrent disease, novel pathogen exposure, and elevated environmental temperatures.

Summary:

Introduction:

· Plasmodium, Haemoproteus, and Leukocytozoon spp. - vector-borne hemoparasites in birds

· wild passerines often reservoirs for hemoparasites

· not generally considered to be pathogenic in most passerine and raptor species

· asymptomatic carriers, low morbidity and mortality despite chronic parasitemia

· Plasmodium – P. relictum and P. elongatum common in North America:

· transmitted via mosquitoes (Culicidae)

· exoerythrocytic stage - replication in host tissues

· erythrocytic phase - invasion of circulating blood cells

· prepatent (exoerythrocytic) acute (erythrocytic) crisis chronic

· acute phase of infection - replication in host tissues leads to inflammatory reaction and tissue necrosis, growth in RBC’s causes hemolysis and anemia

· crisis stage - peak parasitemia

· chronic stage - parasitemia is adequately controlled by the host immune system

· schizogony – asexual reproduction, occurs within host

· first 3 stages of schizogony can cause significant damage to organs before it can be detected in blood

· Haemoproteus:

· transmitted via sand flies aka biting midges (Ceratopogonidae)

· life cycle similar to plasmodium but schizogony is confined to tissues

· Leukocytozoon:

· transmitted via black flies (Simulidae)

· life cycle similar to plasmodium but only gametocytes are found in the blood in RBC and WBC’s

Cases:

· Case series of 5 SNOW housed at Maryland Zoo in Baltimore describes the detection of hemoparasitic infections by blood smear evaluation and PCR, pathology in 2 owls that died, and management of 3 surviving cases

· Case 1 – 6yr F captive bred SNOW

· Found dead in enclosure

· Necropsy - disseminated protozoal infection with pericardial effusion and pneumonia

· Case 2 – 1yr F SNOW

· Leukocytozoon, haemoproteus, and plasmodium on blood smear – increased burden 1 month prior to death then decreased again

· Bird moved to another enclosure and 15 days later bird found dying and arrested

· Necropsy – WNV was cause of death

· changes in spleen suggested protozoal parasitemia and ongoing erythrocyte destruction contributed

· PCR positive for P. relictum

· Case 3 – 1yr F SNOW

· In enclosure with Case 2 when it died

· P. relictum and leukocytozoon found

· Treated with chloroquine and primaquine given rapid decline of other birds – clear 3-4 weeks after treatment

· Recurrence 2.5 months later with P. relictum, Leukocytozoon, Haemoproteus, and Babesia spp detected

· Bird released and recaptured and assessed 2 months after release, no hemoparasites noted

· Case 4 – 4yr M SNOW

· Also housed with Case 2

· Plasmodium and leukocytozoon found in blood with mild leukocytosis and lymphocytosis

· PCR positive for Haemoproteus syrnii

· Treated with chloroquine and primaquine

· Hemoparasite burden improved but leukocytosis and lymphocytosis worsened

· Started itaconazole and another course of chloroquine and primaquine started

· No hemoparasites noted after and bird did well

· Case 5 – 4yr F SNOW

· Also treated for hemoparasites but had lowest burden (plasmodium and haemoproteus)

· Treated with chloroquine and primaquine

· PCR positive for P. relictum

· Found to be positive for Babesia spp. after several courses of treatment

· Treated again with chloroquine and primaquine

· Low level of hemoparasites following treatments but bird did well

Discussion:

· Arctic, Antarctic and island species believed to be more susceptible to infection by hemoparasites, particularly Plasmodium

· increases in parasite burden can an indicator of underlying disease or disease severity

· hemoparasitic disease is not benign in SNOW’s as in other raptors

· stressors likely exacerbated cases described – possibly heat stress

· increased parasitemia occurred during warm weather

· Vector control, cooling, and reducing handling can be implemented to decrease hemoparasitic disease

· Moving birds to new enclosures with new birds may have been a contributing stressor

· Conflicting information exists of chronic impact of hemiparasites in other species

· Gyrfalcons suspected to be more susceptible to Plasmodium infection than other raptor species and show disease and mortality with lower parasite loads, possibly due to stress in captivity

· Morphologic diagnosis along with PCR increases confidence in diagnosis

· studies have shown that PCR alone can underestimate occurrence of mixed infections

· Not all birds infected require treatment, low likelihood of clearing infection

· Treat both stages of plasmodium

· chloroquine for blood stages

· primaquine for tissue stages

· mefloquine and doxycycline have also been used to treat Plasmodium

· SNOW may be sensitivity to hemoparasite infections

· Exacerbated by stressors such as high seasonal temperatures, close proximity to conspecifics, and stress related to medical management in this paper

PRESUMED PHOTORECEPTOR DYSPLASIAS IN PEREGRINE FALCONS (FALCO PEREGRINUS) AND PEREGRINE FALCON HYBRIDS

Bret A. Moore, Christopher J. Murphy, Annajane Marlar, Richard R. Dubielzig, Leandro B. C. Teixeira, et. al.

Journal of Wildlife Diseases, 55(2):325-334

Abstract:

We describe a case series of photoreceptor dysplasia with secondary retinal degeneration in juvenile Peregrine Falcons. Six Peregrine Falcons (Falco peregrinus) and three Peregrine Falcon 3 Prairie Falcon (Falco mexicanus) hybrids had early-life visual deficits. Eight birds had visual defects shortly after hatching, and one bird had visual deficits first noticed at 5 mo of age. Complete ophthalmic examinations were performed in each animal. Eight of the animals had electroretinograms, and nine of the animals had their eyes examined histologically after euthanasia. Ophthalmic examinations did not reveal consistent and potentially blinding abnormalities, including an absence of ophthalmoscopic retinal lesions. Electroretinographic findings included subnormal amplitudes (with rod responses more abnormal than cone responses), with a negative b-wave amplitude occurring in one bird. Histologically, a reduction in the number of photoreceptors was present with numerous degenerative changes to the remaining photoreceptors, including frequent blunting and disorganization of photoreceptor outer segments, decreased numbers of cells in the inner nuclear layer, decreased numbers of ganglion cells, decreased thickness of the nerve fiber layer, and decreased myelinated axons within the optic nerve. Ultrastructurally, only minor cone outer segment changes and occasional phagocytic cells were seen. Results strongly suggested a primary retinopathy, characterized by photoreceptor dysplasia and secondary retinal degeneration with loss of cellular elements throughout the retina. The presence of a similar spectrum of findings in related individuals, the early age of onset, and the relative lack of other environmental, ocular, or systemic abnormalities suggested possible heritability.

Summary:

Introduction:

· Falcons have a greater cone density than humans

· Primary retinopathies rarely reported in birds

· occurs as retinal cell begins to differentiate (ex- photoreceptor cells in photoreceptor dysplasia)

· can be early or late onset

· early onset primary photoreceptor retinopathy

· early visual deficits, severe photoreceptor structural abnormalities, and rapid progression from further retinal degeneration

· late onset primary photoreceptor retinopathy

· developmental abnormalities but variable onset of visual deficits and rate of progression

· Secondary retinopathy – many reports on avian species

· characterized by photoreceptor degeneration following apparently normal photoreceptor development and differentiation

· 9 PEFA and PEFA hybrids presented with visual deficits noted shortly after hatch and diffuse bilateral retinal disease

Results/Discussion:

· 6 PEFA and 3 PEFA x PRFA hybrids presented for visual deficits

· No sex predilection

· 3 birds were from same parents in two different clutches, other birds unrelated

· case series suggests early onset vision loss from various forms of a primary retinopathy is more likely than other causes (nutritional, toxic, systemic disease, neoplastic, photic, traumatic) in some falcons

· retinopathy is likely heritable and autosomal recessive

· heritable retinopathies documented in domestic chickens

· lack of documentation in wild raptors likely because they don’t survive

· signs of retinal degeneration are more difficult to identify on fundic exam in a non-tapetal fundus with anangiotic retinal pattern – ERG’s are important for diagnosis in birds

· histo showed reduced rod and cone numbers, degenerative changes to photoreceptor outer segments, and decrease in thickness of other retinal layers

· ERG showed subnormal photoreceptor amplitudes in all cases

· one bird had negative ERG result - identifies inner retinal dysfunction

· cases more closely resembled photoreceptor dysplasia than either a retinal dysplasia or retinal degeneration

PREVALENCE AND RISK FACTORS OF TRICHOMONAS GALLINAE AND TRICHOMONOSIS IN GOLDEN EAGLE (AQUILA CHRYSAETOS) NESTLINGS IN WESTERN NORTH AMERICA

Benjamin M. Dudek, Michael N. Kochert, Joseph G. Barnes, Peter H. Bloom, Joseph M. Papp, et. al.

Journal of Wildlife Diseases, 54(4):755-764

Abstract:

Avian trichomonosis, caused by the protozoan Trichomonas gallinae, affects bird-eating raptors worldwide. Raptors can develop trichomonosis by feeding on infected prey, particularly Rock Pigeons (Columba livia), which are a reservoir for T. gallinae. Raptors may be particularly vulnerable to T. gallinae infection in degraded habitats, where changes in resources may cause raptors to switch from foraging on native prey to synanthropic avian species such as Rock Pigeons. Golden Eagles (Aquila chrysaetos) typically forage on mammals; however, habitat across much of their range is experiencing degradation through changes in land use, climate, and human encroachment. In 2015, we examined the prevalence of T. gallinae infection in Golden Eagle nestlings across western North America and conducted an intensive study on factors associated with T. gallinae infection and trichomonosis in southwestern Idaho. We found T. gallinae infection in 13% (12/96) of eagle nestlings across 10 western states and in 41% (13/32) of nestlings in southwestern Idaho. At the Idaho site, the probability of T. gallinae infection increased as the proportion of Rock Pigeons in nestling diet increased. Nestlings with diets that consisted of 10% Rock Pigeons had a very high probability of T. gallinae infection. We compared historical (1971–81) and recent (2014–15) diet data and incidence of trichomonosis lesions of nestling eagles in Idaho and found that the proportion of Rock Pigeons in eagle diets was higher in recent versus historical periods, as was the proportion of eagle nestlings with trichomonosis lesions. Our results suggested that localized shifts in eagle diet that result from habitat degradation and loss of historical prey resources have the potential to affect Golden Eagle nestling survival and supported the hypothesis that land use change can alter biologic communities in a way that might have consequences for disease infection and host susceptibility.

Summary:

Introduction:

· Avian trichomonosis - caused by flagellated protozoan parasite Trichomonas gallinae

· commonly found in birds in the Columbidae family

· bird-eating raptors that feed on infected prey are susceptible – often results in mortality

· primarily affects the upper GI of birds

· development of caseous lesions in the oropharynx

· can lead to starvation or suffocation

· naive populations can be severely effected

· high rates of infection found in raptors where loss of native habitat and prey resulted in dietary shifts

· oral pH may affect risk of infection - persists at pH range of 6.5–7.5 but is less viable in more acidic conditions

· Oral pH of nestling COHA promotes infection but oral pH decreases as hawks age, and adults are less susceptible to infection

· Changes to western North American landscapes that have altered prey availability for Golden Eagles, more likely to prey on rock doves

· Study Objectives: document the prevalence of T. gallinae in nestling GOEA, identify the factors associated with infection, and examine whether infection risk has changed over time

· GOEA nestlings sampled throughout W North America during the 2015 breeding season to assess the geographic prevalence

· intensive study conducted in SW Idaho examined whether nestling age, oral pH, or proportion of Rock doves in nestling diet predicted T. gallinae infection rates

· historical (1971–81) and recent (2014–15) data used to examine how nestling diet and incidence of trichomonosis have changed over time at our Idaho study site

M+M:

· Oral swabs collected from nestling GOEA from 11 sites April to June 2015 in western North America

· Samples examined under microscope for motile trichomonads

· DNA extraction and PCR also performed on samples

· Oropharynx of each nestling examined for lesions

· Birds with lesions were treated with carnidazole

· oral pH of 15 eagle nestlings measured every 8–10 days throughout the nestling period at Idaho sites

· presence of lesions compared with historical (1971–81) data documenting lesions

· sex also determined via DNA analysis with blood samples

· nestling diet also assessed by collecting prey remains and pellets

· compared to historical (1971–81) diet data to see if increase in rock doves

Results:

· Prevalence of T. gallinae in non-Idaho GOEA nestlings was 13%

· Prevalence in Idaho was higher - detected in 41% of nestlings and 42% of nests had at least one nestling with positive culture

· 18% of nests had at least one nestling that had a positive culture

· presence of T. gallinae confirmed with PCR in 64% of samples

· reoccurrence of oral lesions observed in 25% of treated nestlings

· Mean nestling age when detected in culture: 23.5 +/- 11.0 d (range 8–38 d)

· Mean age of oral lesion appearance: 30.3 +/- 13.5 d (range 12–49 d)

· Lesions developed 7.2 +/- 7.0 d after positive result via culture

· Nestling age did not predict the probability of infection

· pH decreased with increasing age

· no significant relationship between infection and oral pH

· Proportion of Rock doves in diet predicted T. gallinae infection

· Increased with more rock doves in diet

· 7% of unique diet items found to be rock doves

· Proportion of rock doves in diet of nestlings higher in 2014–15 compared to 1971–81

· Historically, 15% of nestlings had oral lesions compared to 41% in 2015

Discussion:

· High infection rates in Idaho associated with proportion of Rock doves in nestling diet, which has increased significantly compared to historical diets

· Possible reasons for lower prevalence at nest sites outside of Idaho:

· Older nestlings sampled so may have missed infection and mortality

· Diets include fewer rock doves

· Cultured swab samples and PCR results had a 53% agreement

· Trichomonads may have died in transport or possible low density in samples

· Culturing swabs was a reliable indicator of the subsequent development of trichomonosis

Documentation of T. gypaetinii - had pr VITAMIN B6 (PYRIDOXINE HYDROCHLORIDE) TOXICOSIS IN FALCONS

Samour J, Perlman J, Kinne J, Baskar V, Wernery U, Dorrestein G.

Journal of Zoo and Wildlife Medicine. 2016 Jun;47(2):601-8.

Abstract: This manuscript reports three independent accidental cases of vitamin (Vit) B6 toxicosis in

gyrfalcons (Falco rusticolus) and peregrine falcons (Falco peregrinus) and a toxicology study that was conducted to characterize the clinical responses of gyrfalcons and gyrfalcon 3 peregrine falcons to a range of single intramuscular (IM) and oral (PO) doses of Vit B6. Both lethal and nonlethal doses were determined. Twelve female gyrfalcons died following IM injection of 1 ml of a vitamin B preparation. Within 30 min of injection, the birds passed pistachio green-colored urates and progressed to vomiting, anorexia, cessation of normal activity, ptosis, collapse, and death, occurring 24–36 hr post injections. Three individuals vomited frothy, partially digested blood and had clonic spasms and convulsions. Postmortem and histopathology revealed multifocal severe hepatic necrosis, splenic lymphoid tissue depletion and hemorrhages with arterial necrosis, and acute renal tubular necrosis. Following administration of a different, oral, mineral-vitamin supplement, a total of 21 peregrine falcons in two separate European facilities died suddenly. Histology of the liver showed diffuse congestion and multifocal coagulative necrosis with mild infiltration of heterophils. The particular nutritional supplement, used by both breeders, was analyzed and found to contain 5–9.7% Vit B6. Other randomly selected lots of the product contained 0.007–0.27% Vit B6. According to the product label, Vit B6 should have been present at 0.004%. To confirm the hypothesis that Vit B6 was responsible for the deaths of the falcons in Abu Dhabi, Vit B6 (British Pharmacopoeia [BP] grade) in powder form was diluted in water for injection and administered IM to four groups of falcons. Groups of four gyrfalcon3peregrine hybrid falcons or gyrfalcons (or both) were given a single IM dose of 5, 10, 15, or 20 mg/kg of Vit B6 or received an oral dose of 25, 50, or 75 mg of Vit B6. Only birds in the lowest dose groups survived. The maximum nonlethal single doses of Vit B6 in falcons were 5 mg/kg i.m. and 25 mg/kg p.o.

Background: 

· Vitamin B6 (pyridoxine) water soluble and part of Vit B complex

· Vit B6: absorbed from diet appear in liver, converted into pyridoxal 5-phosphate: metabolically active form, cofactor for essential enzymes (birds/mammals). 

· One other report of avian B6 toxicity in pigeons (but chickens unaffected by same dose)

Key points: 

· 3 accidental fatal toxicities of Vit B6 in peregrine and gyrfalcons, IM and oral

· CS: green urates, vomiting. Path: liver/splenic necrosis, acute renal tubular necrosis.

· Study of IM (5-20 mg/kg) and oral (25-75 mg/kg)

· All animals died except the lowest of the IM (5 mg/kg) and PO (25 mg/kg) groups.

· Similar path as accidental cases. congestion and perivascular hemorrhages of the lungs

· For many human formulations of B complex. If falcons are dosed at 20mg/kg of Vit B1, they get 40mg/kg Vit B6 which is lethal. 

· B6= The highest single non-lethal dose is 5mg/kg IM and 25mg/kg PO, daily supplementation is likely lower. 

· 200mg/kg kills pigeons but not chickens. Falcons were 8x are more sensitive than pigeons. 

Take home: Beware supplementing Vitamin B complex to birds, 20 mg/kg vitamin B1 may lead to lethal doses B6. In falcons see lung, liver, splenic, renal pathology. The highest non-lethal single doses were 5mg/kg IM, 25mg/kg PO. Avian species differences, falcons most sensitive, then pigeons, chickens less.

Cloacal prolapse in raptors: review of 16 cases

Dutton TA, Forbes NA, Carrasco DC.

Journal of Avian Medicine and Surgery. 2016 Jun;30(2):133-41.

 

Abstract: Sixteen cases of cloacal prolapse in raptors were reviewed in this study. Colonic prolapse was the most common presentation (56% of cases). Red-tailed hawks (Buteo jamaicensis) were overrepresented, comprising 66% of colonic prolapse cases. In cases of colonic prolapse, postsurgical stricture formation was a commonly identified complication after resection and anastomosis of the colon. A novel technique was used in 2 cases of colonic prolapse, in which sterile, semirigid rubber tubing was placed in the distal colon and removed per-cloaca at the end of the procedure; this facilitated a secure, fluid-tight anastomosis while maintaining sufficient intestinal lumen. Oviductal prolapse (31% of cases) was associated with the most guarded prognosis (40% treatment success). Cloacoliths were treated successfully in 2 birds (13% of cases) by minimally invasive per-cloacal manual removal.

 

Intro, M&M

· Cloacal prolapse in raptors is rare compared to clinical avian practice

· 3 chambers of cloaca: coprodeum, urodeum, and proctodeum

· serves the digestive, urinary, and reproductive tracts.

· Sixteen cases of cloacal prolapse in raptors were reviewed in this study

 

Results/Conclusion

· Colonic prolapse was the most common (56%), with red-tailed hawks overrepresented (66%)-

· Enteritis most common cause – Campylobacter, coccidia

· Stricture of colon commonly seen complication of surgical colonic R&A

· New technique: plastic tubing was used to maintain lumen diameter, decreased stricture.

· Cases where anastomosis was performed caudal to cecal remnant.

· Overall ~90% treatment success with colon prolapse.

· Cloacal prolapse due to cloacolith fixed easily, minimally invasive

· Oviductal prolapse carried worse prognosis – 40% success. Assoc with egg binging, peritonitis.

· Surgery typically performed.

 

Take home: Cloacal prolapse may be more common in raptors than previously thought. Colonic most common and carries better prognosis than oviduct. Redtail hawk overrepresented in this study. Strictures are common following R& A and may be reduce with tube technique.

 

DETERMINING RAPTOR SPECIES AND TISSUE SENSITIVITY FOR IMPROVED WEST NILE VIRUS SURVEILLANCE

Kritzik KL, Kratz G, Panella NA, Burkhalter K, Clark RJ, Biggerstaff BJ, Komar N.

Journal of Wildlife Diseases, 54(3), 2018, pp. 528–533

Abstract: Raptors are a target sentinel species for West Nile virus (WNV) because many are susceptible to WNV disease, they are easily sighted because of their large size, and they often occupy territories near human settlements. Sick and dead raptors accumulate at raptor and wildlife rehabilitation clinics. However, investigations into species selection and specimen type for efficient detection of WNV are lacking. Accordingly, we evaluated dead raptors from north-central Colorado, US and southeast Wyoming, US over a 4-yr period. Nonvascular mature feathers (‘‘quill’’), vascular immature feathers (‘‘pulp’’), oropharyngeal swabs, cloacal swabs, and kidney samples were collected from raptor carcasses at the Rocky Mountain Raptor Program in Colorado from 2013 through 2016. We tested the samples using real-time reverse transcriptase-PCR. We found that 11% (53/482) of raptor carcasses tested positive for WNV infection. We consistently detected positive specimens during a 12- wk span between the second week of July and the third week of September across all years of the study. We detected WNV RNA most frequently in vascular feather pulp from Cooper’s Hawk (Accipiter cooperii). North American avian mortality surveillance for WNV using raptors can obviate necropsies by selecting Cooper’s Hawk and Red-tailed Hawk (Buteo jamaicensis) as sentinels and targeting feather pulp as a substrate for viral detection.

 

Intro

· Avian carcasses used to detect WNV activity and tissue selection in raptors for surveillance is unknown

· Objective: sample carcasses for WNV and HPAIV RNA in selected tissues

M&M:

· Samples submitted from dead raptors over 3 years within 48 hours of death.

· Samples: nonvascular feather quill, pulp from immature flight feather, oropharyngeal swab, cloacal swab, kidney tissue.

· Reverse transcriptase PCR.

Results

· 11% of carcasses positive for WNV on at least one sample. Cooper’s Hawk had the highest infected percentage

· Eleven species positive. High number of Swainson and red tailed hawks in addition to Coopers

· Feather pulp was the most sensitive tissue for WNV RNA. Kidney second.

· Feather pulp highest number of + in Coopers and Swainson’s hawks

· Consistently tested positive from July to the end of September

Discussion

· Cooper’s hawk good candidate for WNV surveillance among raptors

· RTHA and Swainsons in the west coast also a good option

· Most sensitive tissue type was the feather pulp

· Similar findings in corvid carcasses. However vascular tissue is not always available

· If necropsies performed, kidney tissue can be used as a substitute

· eviously only been reported in Old World vultures

· If GOEA nestling diets consisted of >10% Rock doves, then nestlings had a high probability of T. gallinae infection