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

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.

Effectiveness of Physical Therapy as an Adjunctive Treatment for Trauma-induced Chronic Torticollis in Raptors.

Management of trauma-induced chronic torticollis in raptors has historically been challenging. Euthanasia is common in affected birds because of their inability to maintain normal cervical position, although they may be able to function normally. To assess effectiveness of physical therapy of the neck and head as an adjunct treatment for this condition, a case-control study was done in raptors admitted to the Rocky Mountain Raptor Program from 2003 to 2010. Eleven cases were identified with a diagnosis of chronic torticollis resulting from traumatic brain injury. Five cases were treated with physical therapy of the head and neck, and 6 control cases did not receive any physical therapy for the torticollis. Of the control cases, 0 of 6 had resolution of the torticollis, 0 of 6 were released, and 5 of 6 were euthanatized. Of the treated cases, 4 of 5 had complete resolution of the torticollis and 5 of 5 were released. Resolution of torticollis differed significantly between cases receiving physical therapy and controls. These results indicate that physical therapy should be used as an adjunctive therapy in cases of chronic torticollis induced by trauma in raptors because it results in better resolution of the torticollis and increased likelihood of release.

A multimodal approach to management of suspected neuropathic pain in a prairie falcon (Falco mexicanus).

An adult male prairie falcon (Falco mexicanus) was presented for evaluation and treatment of self-inflicted wounds along the right proximal patagium. The bird had started self-traumatizing approximately 1 month after fracturing the right metacarpus, although the fracture had stabilized, surface wounds had healed completely, and treatment with a nonsteroidal antiinflammatory drug had been administered. The bird was treated with gabapentin (11 mg/kg p.o. q12h), ketamine (0.5 mg/kg i.m. q24h), and low level laser therapy (LLLT) (<5 mW, 630-680 nm, 5-second application per site) for 3 weeks, but, despite initial improvement, new self-inflicted wounds appeared at the same site. Approximately 1.5 months later, a radial and medianoulnar nerve block was performed by using bupivacaine (2 mg/kg) and medetomidine (0.5 microg/kg). In addition, the dosing interval of ketamine was increased to q12h, and the dose of gabapentin was increased 7.5-fold. A higher energy and wavelength of LLLT (1040 mW, 830 nm, 2 J/cm2) was applied once to the injured region and fracture site, then the original LLLT protocol was applied once daily. After 2.5 months, the wounds healed completely and no further mutilation took place. Once deemed ready for release, the falcon was returned to the wild after 181 days in captivity. This is the first reported application of successful multimodal analgesia in a raptor with uncontrolled neuropathic pain.

Clinical evaluation and outcomes of naturally acquired West Nile virus infection in raptors.

West Nile virus (WNV) infection and associated disease and mortality have been documented in numerous North American raptor species. Information regarding clinical presentations and long-term outcomes of WNV-infected raptors is important in the clinic for the diagnosis, treatment, and assessment of prognosis, as well as for understanding potential population level effects on raptor species. Raptors of 22 species admitted to a rehabilitation clinic were tested, from 2002 to 2005, for previous and acute WNV infection, while comparing clinical syndromes, trauma, and rehabilitation outcomes. Forty-two percent of admitted raptors (132/314) had been infected with WNV, and these presented with a WNV-attributed clinical disease rate of 67.4% (89/132). West Nile virus-infected raptors were less likely to be released (79/132 [59.8%]) than negative raptors (138/182 [75.8%]) and more likely to die or be euthanized (47/132 [35.6%] for WNV-infected vs. 32/182 [17.6%] for WNV-negative). However, WNV-infected raptors with neurologic disease were no less likely to be released (29/53 [54.7%]) than those without neurologic disease (50/79 [63.3%]). Clinical WNV-associated syndromes varied among species. Great horned owls (Bubo virginianus) were more likely to have neurologic signs, whereas American kestrels (Falco sparverius) and Swainson's hawks (Buteo swainsonii) were less likely to have neurologic signs. These results suggest that free-ranging raptors are frequently infected with WNV and that clinical syndromes differ among species. WNV has potentially devastating effects on raptors; however, rehabilitation of WNV-infected raptors can lead to positive outcomes, even for those having had severe neurologic disease.

Naturally induced humoral immunity to West Nile virus infection in raptors.

West Nile virus (WNV) infection can be fatal to many bird species, including numerous raptors, though population- and ecosystem-level impacts following introduction of the virus to North America have been difficult to document. Raptors occupy a diverse array of habitats worldwide and are important to ecosystems for their role as opportunistic predators. We documented initial (primary) WNV infection and then regularly measured WNV-specific neutralizing antibody titers in 16 resident raptors of seven species, plus one turkey vulture. Most individuals were initially infected and seroconverted between July and September of 2003, though three birds remained seronegative until summer 2006. Many of these birds became clinically ill upon primary infection, with clinical signs ranging from loss of appetite to moderate neurological disease. Naturally induced WNV neutralizing antibody titers remained essentially unchanged in some birds, while eight individuals experienced secondary rises in titer presumably due to additional exposures at 1, 2, or 3 years following primary infection. No birds experienced clinical signs surrounding or following the time of secondary exposure, and therefore antibodies were considered protective. Results of this study have implications for transmission dynamics of WNV and health of raptor populations, as well as the interpretation of serologic data from free-ranging and captive birds. Antibodies in raptors surviving WNV may persist for multiple years and protect against potential adverse effects of subsequent exposures.

Surveillance for West Nile virus in clinic-admitted raptors, Colorado.

In 2005, 13.5% of clinic-admitted raptors in northern Colorado tested positive for West Nile virus (WNV). Clinic-admitted-raptor surveillance detected WNV activity nearly 14 weeks earlier than other surveillance systems. WNV surveillance using live raptor admissions to rehabilitation clinics may offer a novel surveillance method and should be considered along with other techniques already in use.

Retrospective study of morbidity and mortality of raptors admitted to Colorado State University Veterinary Teaching Hospital during 1995 to 1998.

A retrospective study was conducted to identify causes of morbidity and mortality of free-living raptors in northeast Colorado and the surrounding areas of Nebraska and Wyoming. The study included 409 raptors, representing 23 species, admitted to the Colorado State University Veterinary Teaching Hospital, Fort Collins, Colorado, USA, from 1995 to 1998. Causes of morbidity and mortality were identified as trauma (66.3%), orphaned young (15.6%), unknown (9.0%), infectious disease (4.4%), metabolic and nutritional disease (2.2%), toxicosis (2.0%), and degenerative disease (0.5%). Trauma was the most frequent cause of morbidity and mortality for all species and during all seasons.