Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California.

Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats.

CLINICAL COPPER TOXICOSIS IN A LARGE MIXED GROUP OF MARINE INVERTEBRATES.

A mixed group of 441 marine invertebrates was collected in Southern California. After a large mortality event, numerous water quality parameters were evaluated. Copper was present at 33 µg/L, which is below the documented toxic level. No other toxins were identified. To investigate whether copper was the etiology for the mass mortality, purple sea urchins, Strongylocentrotus purpuratus , were used as sentinel species, as they were the most severely affected during the mortality event. Purple sea urchins were placed in multiple test systems of varying copper concentrations and died in periods of time proportionate to copper concentrations. Clinical signs, disease progression, and pathologic lesions were similar between test systems and the original mortality event. Copper caused disease and death in purple sea urchins at concentrations from 15 to 50 µg/L. The source of the copper toxicity was identified as sand filters contaminated by brass pump components.

Densovirus associated with sea-star wasting disease and mass mortality.

Populations of at least 20 asteroid species on the Northeast Pacific Coast have recently experienced an extensive outbreak of sea-star (asteroid) wasting disease (SSWD). The disease leads to behavioral changes, lesions, loss of turgor, limb autotomy, and death characterized by rapid degradation ("melting"). Here, we present evidence from experimental challenge studies and field observations that link the mass mortalities to a densovirus (Parvoviridae). Virus-sized material (i.e., <0.2 µm) from symptomatic tissues that was inoculated into asymptomatic asteroids consistently resulted in SSWD signs whereas animals receiving heat-killed (i.e., control) virus-sized inoculum remained asymptomatic. Viral metagenomic investigations revealed the sea star-associated densovirus (SSaDV) as the most likely candidate virus associated with tissues from symptomatic asteroids. Quantification of SSaDV during transmission trials indicated that progression of SSWD paralleled increased SSaDV load. In field surveys, SSaDV loads were more abundant in symptomatic than in asymptomatic asteroids. SSaDV could be detected in plankton, sediments and in nonasteroid echinoderms, providing a possible mechanism for viral spread. SSaDV was detected in museum specimens of asteroids from 1942, suggesting that it has been present on the North American Pacific Coast for at least 72 y. SSaDV is therefore the most promising candidate disease agent responsible for asteroid mass mortality.

Nasal mass removal in the koala (Phascolarctos cinereus).

Nasal masses in the koala (Phascolarctos cinereus) are not uncommon and can be challenging to diagnose and treat. Differential diagnoses for nasal masses in the koala are cryptococcal granulomas, nasal polyps, nasal adenocarcinoma, and osteochondromatosis. This report describes successful surgical approaches for two adult koalas with nasal masses and includes photodocumentation and description of the anatomy of the koala nasal passages from the postmortem transverse sectioning of a normal koala head. Surgical removal of the nasal masses in these koalas resulted in a rapid resolution of clinical signs.

Preshipment testing success: resolution of a nasal sinus granuloma in a captive koala (Phascolarctos cinereus) caused by Cryptococcus gattii.

A 3-yr-old female koala (Phascolarctos cinereus) was diagnosed with a nasal sinus granuloma caused by Cryptococcus gattii after a pre-shipment examination revealed a latex cryptococcal agglutination titer of 1:512. Successful medical and surgical treatment of the granuloma was monitored using serial latex cryptococcal agglutination titers, serum levels of antifungal drugs, and advanced imaging.

Treatment of lead toxicity and crop stasis in a California condor (Gymnogyps californianus).

A free-ranging California condor (Gymnogyps californianus) presented severely dehydrated, unable to stand, very weak, and with a distended crop. Toxicologic analysis revealed an elevated blood lead level of 291.4 microg/ ml. There was no evidence of lead exposure on radiographs. The condor was treated with chelating agents and intensive supportive care. Over a period of 10 days, a majority of its clinical signs improved, and lead levels dropped to near normal. However, the condor was left with a severe, persistent crop stasis and malnutrition. An esophagostomy tube, and later an ingluviostomy tube, were placed and maintained for a period of 1 mo. The condor was managed with continuous infusion feeding. After the feeding tube was removed, the condor was managed with small amounts of soft food orally. After 10 wk of treatment, the crop returned to normal function.