Wendi D. Roe

An atypical genotype of Toxoplasma gondii as a cause of mortality in Hector's dolphins (Cephalorhynchus hectori)

Hectors dolphins (Cephalorhynchus hectori) are a small endangered coastal species that are endemic to New Zealand. Anthropogenic factors, particularly accidental capture in fishing nets, are believed to be the biggest threat to survival of this species. The role of infectious disease as a cause of mortality has not previously been well investigated. This study investigates Toxoplasma gondii infection in Hectors dolphins, finding that 7 of 28 (25%) dolphins examined died due to disseminated toxoplasmosis, including 2 of 3 Mauis dolphins, a critically endangered sub-species. A further 10 dolphins had one or more tissues that were positive for the presence of T. gondii DNA using PCR. Genotyping revealed that 7 of 8 successfully amplified isolates were an atypical Type II genotype. Fatal cases had necrotising and haemorrhagic lesions in the lung (n=7), lymph nodes (n=6), liver (n=4) and adrenals (n=3). Tachyzoites and tissue cysts were present in other organs including the brain (n=5), heart (n=1), stomach (n=1) and uterus (n=1) with minimal associated inflammatory response. One dolphin had a marked suppurative metritis in the presence of numerous intra-epithelial tachyzoites. No dolphins had underlying morbillivirus infection. This study provides the first evidence that infectious agents could be important in the population decline of this species, and highlights the need for further research into the route of entry of T. gondii organisms into the marine environment worldwide.

Use of radiography to determine age class and assist with the post-mortem diagnostics of a Bryde's whale (Balaenoptera brydei )

Abstract Vessel collisions are considered an important source of mortality for some cetacean species, and this is likely for the New Zealand Brydes whale (Balaenoptera brydei), a species currently classified as “nationally critical”. Nevertheless, the occurrence and frequency of vessel strikes involving whales in New Zealand waters is yet to be systematically evaluated. Herein, we document the use of radiography as a diagnostic tool to examine the pectoral nippers of a Brydes whale carcass recovered from Hauraki Gulf, New Zealand. To determine age class, radiographs were used to assess the degree of epiphysial fusion in the pectoral flippers. Additionally, evidence of bone damage and repair was examined in an attempt to clarify cause of mortality. Radiographs were definitive for age‐class determination, revealing the specimen to be a juvenile, as evidenced by open physes, incompletely ossified epiphyses, and incompletely ossified cuboidal bones of the carpus. The degree of epiphyseal development of the distal radial and ulnar secondary ossification centres suggests a late stage two or early stage three degree of development. Radiographs were less definitive in clarifying cause of mortality. Bilateral distal antebrachial fractures were observed on both the left and right pectoral flippers. The fractures evident in the distal right antebrachium of the left flipper were considered atypical of acute blunt trauma. The fracture fragment ends were not sharp edged as expected, but instead exhibited the appearance of remodelled and/or pulverised fracture fragment ends. Regardless of cause, the degree of bone remodelling and callus formation is evidence that the whale likely survived any initial trauma, thus suggesting mortality was not immediate. However, the absence of appropriate histopathology sampling and a systematic necropsy prevent confirmation of this hypothesis.

Squamous cell carcinoma in a tuatara (Sphenodon punctatus)

Abstract CASE HISTORY: A mature male tuatara was presented with a history of recurrent cloacal prolapse. CLINICAL AND PATHOLOGICAL FINDINGS: The prolapsed tissue included a 12 mm diameter mass, which histologically showed cords and nodules of neoplastic epithelial cells. DIAGNOSIS: The mass was diagnosed as a squamous cell carcinoma with ulceration of the overlying stratified squamous epithelium and diffuse inflammation of the surrounding dermis. CLINICAL RELEVANCE: This case presented a rare opportunity to investigate squamous cell carcinoma in a long-lived lower vertebrate species. Future recurrence or metastasis of the mass may add useful information to the current base of knowledge of the behaviour of malignant neoplasms in reptiles.

Four Cases of Fatal Toxoplasmosis in Three Species of Endemic New Zealand Birds

SUMMARY Four cases of fatal toxoplasmosis in three endemic New Zealand avian species are reported. Between 2009 and 2012, two kereru (Hemiphaga novaeseelandiae), one North Island brown kiwi (Apteryx mantelli), and one North Island kaka (Nestor meridionalis) were submitted for necropsy examination. On gross postmortem, the kiwi had marked hepatosplenomegaly while the kaka and two kereru had swollen, slightly firm, deep-red lungs. Histologically there was extensive hepatocellular necrosis in the liver of the kiwi while the kaka and kereru showed severe fibrinous bronchointerstitial pneumonia. In the kiwi, protozoal organisms were present within both hepatocytes and Kupffer cells of the liver and within the epithelial cells and macrophages of the interstitium of the lungs in the kaka and two kereru. The diagnosis of toxoplasmosis was confirmed with immunohistochemistry and PCR of paraffin-embedded formalin-fixed tissue of the liver, lungs, or both. Genotyping of up to seven markers revealed that an atypical Type II isolate of Toxoplasma gondii was present in at least three of the cases. This study provides evidence that T. gondii can cause mortality in these endemic species and suggests further research is needed to determine the full extent of morbidity and mortality caused by this parasite in New Zealands unique avifauna. RESUMEN Reporte de Caso—Cuatro casos de toxoplasmosis fatal en tres especies de aves endémicas de Nueva Zelanda. Se reportaron cuatro casos de toxoplasmosis fatal en tres especies aviares endémicas de Nueva Zelanda. Entre los años 2009 y 2012, dos palomas neozelandesa (Hemiphaga novaeseelandiae), un kiwi marrón (Apteryx mantelli), y un kaka (Nestor meridionalis) se sometieron al examen de necropsia. Durante el examen postmortem macroscópico, el kiwi tenía marcada hepatoesplenomegalia, mientras que el kaka y las dos palomas neozelandesas tenían los pulmones inflamados, un poco firmes y de color rojo oscuro. Histológicamente había una extensa necrosis hepatocelular en el hígado del kiwi mientras que el kaka y las dos palomas neozelandesas mostraron severa neumonía broncointersticial fibrinosa. En el kiwi, estaban presentes organismos protozoarios dentro de los hepatocitos y de las células de Kupffer en el hígado, y en el kaka y en las dos palomas neozelandesas se observaron dentro de las células epiteliales y en los macrófagos del intersticio del pulmón. El diagnóstico de toxoplasmosis se confirmó con inmunohistoquímica y PCR de tejido de hígado y pulmón o de ambos, fijado con formalina e incluido en parafina. La genotipificación de hasta siete marcadores reveló que un aislamiento atípico Tipo II de Toxoplasma gondii estaba presente en al menos tres de los casos. Este estudio proporciona evidencia de que T. gondii puede causar mortalidad de estas especies endémicas y sugiere que se necesita más investigación para determinar la magnitud de la morbilidad y mortalidad causada por este parásito en fauna aviaria que es única de Nueva Zelanda.

Septicaemia and meningitis caused by infection of New Zealand sea lion pups with a hypermucoviscous strain of Klebsiella pneumoniae

This study describes a syndrome of neonatal septicemia and meningitis in New Zealand sea lions, caused by a strain of Klebsiella pneumoniae that is phenotypically similar to strains causing environmentally-acquired septicemia and neuro-invasive disease in humans. Between late 2006 and early 2010, 123 pups from the Enderby Island breeding colony died of K. pneumoniae infection, with lesions including fibrinous to fibrinosuppurative meningitis, subdural hemorrhage, septic arthritis, herniation and hemorrhage of the cerebellar vermis, lymphadenitis and cellulitis. This infection was responsible for 58% of observed pup mortality over this time period, with most deaths occurring in the latter part of the breeding season (mid February onwards). The results of this study suggest that the pattern of this disease has changed since it was first described in 2002, when most deaths occurred early in the season (early to mid-January), and that it is an important and consistent cause of pup mortality in this population. In addition, a similar disease syndrome and bacterial strain was diagnosed in a single pup in a fragile recolonizing New Zealand sea lion population on mainland New Zealand, and the potential effect on this population is unknown but could have a negative impact on recolonisation at this site.

A retrospective study of post-mortem examination findings in takahe (Porphyrio hochstetteri)

Abstract AIMS: To identify the major diseases or disease processes affecting both captive and wild populations of takahe (Porphyrio hochstetteri) in birds submitted for post-mortem examination between 1992 and 2007, and to survey archived wild dead takahe for the presence of Erysipelothrix rhusiopathiae. METHODS: Reports of 199 post-mortem examinations submitted between 1992 and 2007 were reviewed retrospectively. The reports comprised 56 eggs, 51 chicks up to 6 months of age, 13 sub-adults 6–18 months old, 74 adults and five birds where age was not recorded. Bone marrow flushed from the keel of 34 frozen adult takahe was assayed for the presence of E. rhusiopathiae, using PCR analysis. RESULTS: Of the eggs examined, 6/56 (11%) had no recorded diagnosis, 24/56 (43%) were infertile and 26/56 (46%) showed embryonic mortality at various stages. Excluding eggs, the cause of death could not be determined in 64/138 (46%) birds with a recorded age that were examined. Contributing factors for the low rate of diagnosis included advanced decomposition of many carcasses, the freezing of some birds prior to pathological investigation, long delays between recovery and submission for post-mortem examination, and variation in the extent of post-mortem examination and ancillary diagnostic testing. Common post-mortem examination findings in chicks included those related to cardiac disease [11/51 (22%)], infectious or inflammatory disease [9/51 (18%)] and trauma [7/51 (14%)]. In adult birds, the most common post-mortem examination findings were due to infectious or inflammatory disease [15/74 (20%)] including septicaemia due to E. rhusiopathiae [3/74 (7%)], followed by degenerative conditions due to diet, age and husbandry [9/74 (12%)]. Bacteria implicated in the causes of death included Escherichia coli, E. rhusiopathiae, Salmonella enterica serovar Typhimurium, and Pseudomonas aeruginosa. Only 1/34 (3%) of the frozen carcass examined using PCR was positive for E. rhusiopathiae. CONCLUSIONS: This study highlights a need for improved recovery, storage and submission of dead takahe for pathological examination; consistency in post-mortem examination, ancillary testing and recording of findings; and finally, regular communication between wildlife pathologists, conservation workers and representatives of Ngai Tahu.

EVIDENCE OF LEAD EXPOSURE IN A FREE-RANGING POPULATION OF KEA (NESTOR NOTABILIS)

Kea (Nestor notabilis) are high country parrots endemic to New Zealand. The foraging behavior and inquisitive nature of Kea have led to incidences of foreign substance ingestion, including lead. Between April 2006 and November 2007, 38 Kea in Aoraki/Mount Cook National Park, New Zealand, were captured, and blood was sampled for blood lead analysis. All birds sampled had detectable blood lead with concentrations ranging from 0.028 mg/l to 3.43 mg/l (mean±SE, 0.428±0.581 mg/l). A retrospective analysis of necropsy reports and archived samples from 15 wild Kea from various South Island locations also was carried out. Seven of these birds (five from the Aoraki/Mount Cook area) died with clinical signs consistent with lead toxicosis and had liver and/or kidney lead levels reported to cause lead toxicity in other avian species. All seven of these birds also had lead inclusions (Ziehl-Neelson positive intranuclear inclusion bodies) in the renal tubular epithelial cells. These are considered diagnostic of lead toxicity in other species. This study showed that lead exposure is ubiquitous in the sampled population and may be an important contributing factor in Kea morbidity and mortality. As a result of these findings, lead abatement in areas frequented by Kea is being initiated.

Serologic Evaluation of New Zealand Sea Lions for Exposure to Brucella and Leptospira spp.

A serologic survey of anti-Brucella and antileptospiral antibodies was conducted on 147 adult, female New Zealand sea lions (Phocarctos hookeri). Most sea lions (n=138) were sampled at Sandy Bay, Enderby Island, Auckland Islands (50°30′S, 166°17′E), January 2000–March 2005. Nine were sampled at Otago, New Zealand (46°0′S, 170°40′E); four in April 2008 and five in March 2009. Serum from one of the Enderby Island females was weakly positive for antibodies to Brucella abortus using the competitive enzyme-linked immunosorbent assay, and one female had a low titer for Leptospira interrogans serovar pomona using the microscope agglutination test. All serum samples from Otago animals were negative. Brucellosis and leptospirosis are therefore considered unlikely to play a major role in population dynamics of these populations, and the low antibody prevalence of these agents suggests that they are an unlikely source of infection for humans, wildlife, or domestic species on mainland New Zealand.

Microphthalmia in Texel lambs

Abstract AIM: To describe an outbreak of congenital microphthalmia in Texel lambs in New Zealand. METHODS: Affected eyes were fixed in 10% formol saline, processed routinely for histopathology and stained with haematoxylin and eosin, Holme’s silver and haematoxylin with and without luxol fast blue, and luxol fast blue alone. RESULTS: Macroscopically, the globes and optic nerves were hypoplastic. Histologically, all embryonic components of the eye were present, but the lens, ciliary body, iris and retina were dysplastic. Axons of the hypoplastic optic nerve were poorly myelinated. CONCLUSIONS: Congenital microphthalmia occurs in Texel sheep in New Zealand, and is likely inherited as an autosomal recessive trait.

The aetiology of wobbly possum disease: Reproduction of the disease with purified nidovirus

The objective of this study was to investigate a role of a recently discovered marsupial nidovirus in the development of a neurological disease, termed wobbly possum disease (WPD), in the Australian brushtail possum (Trichosurus vulpecula). Four possums received 1 mL of a standard inoculum that had been prepared from tissues of WPD-affected possums, 4 possums received 1.8 mL (1 × 10(6) TCID50) of a cell lysate from inoculated cultures, and 4 possums received 1 mL (× 10(7) TCID50) of a purified WPD isolate. All but one possum that received infectious inocula developed neurological disease and histopathological lesions characteristic for WPD. High levels of viral RNA were detected in livers from all possums that received infectious inocula, but not from control possums. Altogether, our data provide strong experimental evidence for the causative involvement of WPD virus in development of a neurological disease in infected animals.