To identify risk factors associated with coccidiosis in kiwi (Apteryx spp.) using a retrospective... more To identify risk factors associated with coccidiosis in kiwi (Apteryx spp.) using a retrospective analysis of historical data from kiwi examined post-mortem, and to determine the prevalence of coccidial oocysts in the droppings of wild and captive kiwi. Necropsy reports were examined from kiwi submitted to the National Wildlife Mortality Database of New Zealand (Huia) between February 1977 and May 2011. All cases that reported histological examination of one or more hepatic, intestinal or renal tissues were included in the study (n=372). Data collated for analysis included the presence or absence of coccidiosis in one or more tissues, age, host species, habitat, and season of submission. Fisher's exact test was used to determine the association between each independent variable and the prevalence of coccidiosis. Droppings opportunistically collected from wild and captive kiwi between January 2008 and June 2010 were also examined for the presence of coccidial oocysts. Coccidiosis was evident in 47/372 (12.6%) kiwi examined post-mortem and was considered the primary cause of death in 12/47 (26%) infected cases. Examination of 412 droppings from wild and captive kiwi collected over a 29-month period revealed that 98 (23.8%) samples contained coccidia at the time of sampling. Enteric (n=27) coccidiosis was the most common form diagnosed using histology, followed by renal (n=19) and hepatic (n=11), with splenic (n=2) and pulmonary (n=1) infections infrequently seen. Many kiwi demonstrated infections in multiple tissues. The prevalence of coccidiosis was greater in juvenile kiwi (36/148, 24.3%) than adults (8/133, 6.0%) or chicks (2/83, 2.4%) (p<0.001), although there was no difference in mortality between age groups. Season of year was also associated with overall prevalence (p=0.05), with most cases being diagnosed in the autumn and winter. Coccidiosis was histologically evident in four of five species of kiwi examined, and in all host species upon analysis of droppings. Host species or habitat (captive vs. wild) did not influence the prevalence of disease detected histologically. Age and season were the only factors that influenced the prevalence of coccidiosis in kiwi in this study. Coccidiosis was present in all species of kiwi, and this is the first report of coccidiosis in rowi (Apteryx rowi).
The continued publication of the Journal of Wildlife Diseases depends on the selfless contributio... more The continued publication of the Journal of Wildlife Diseases depends on the selfless contributions of our volunteer peer reviewers. The editors, officers, and members of the Wildlife Disease Association acknowledge and express our sincere appreciation to the following individuals who completed reviews for Volume 53 of the Journal of Wildlife Diseases (reviews completed 1 July 2016–11 July 2017).*
Clinical and laboratory findings in 15 unreported cases of avian cryptococcosis from Australia we... more Clinical and laboratory findings in 15 unreported cases of avian cryptococcosis from Australia were collated and contrasted with 11 cases recorded in the literature. Cryptococcus species produced localized invasive disease of the upper respiratory tract of captive parrots living in Australia. This resulted in signs referable to mycotic rhinitis or to involvement of structures contiguous with the nasal cavity, such as the beak, sinuses, choana, retrobulbar space and palate. Parrots of widely differing ages were affected and of the seven birds for which sex was determinable, six were male. Cryptococcus bacillisporus (formerly C. neoformans var. gattii) accounted for four of five infections in which the species or variety was determinable, suggesting that exposure to eucalyptus material may be a predisposing factor. In these cases, Cryptococcus appeared to behave as a primary pathogen of immunocompetent hosts. One tissue specimen was available from an Australian racing pigeon with mini...
Avian pathology : journal of the W.V.P.A, Jan 6, 2016
We investigated an epidemic mortality cluster of yellow-eyed penguins (Megadyptes antipodes) that... more We investigated an epidemic mortality cluster of yellow-eyed penguins (Megadyptes antipodes) that involved 67 moribund or dead birds found on various beaches of the Otago Peninsula, New Zealand, between January 21 and March 20, 2013. Twenty-four carcases were examined postmortem. Histological lesions of pulmonary, hepatic and splenic erythrophagocytosis and haemosiderosis were found in 23 of 24 birds. Fifteen birds also had haemoglobin-like protein droplets within renal tubular epithelial cells. Despite consistent histological lesions, a cause of death could not be established. Virology, bacteriology and molecular tests for avian influenza, avian paramyxovirus-1, avipoxvirus, Chlamydia psittaci, Plasmodium spp, Babesia spp, Leucocytozoon spp, and Toxoplasma gondii were negative. Tissue concentrations of a range of heavy metals (n = 4 birds) were consistent with low level exposure, while examination of proventricular contents and mucus failed to detect any marine biotoxins or Clostri...
Diphtheritic stomatitis is a seasonal disease that has been recognized as a syndrome in Yellow-ey... more Diphtheritic stomatitis is a seasonal disease that has been recognized as a syndrome in Yellow-eyed Penguin ( Megadyptes antipodes ) chicks in New Zealand for >10 yr. It was present in about 50% of 234 chicks examined since 2002 and is characterized by a thick serocellular exudate in the oral cavity of 1-4-wk-old chicks. The syndrome includes inanition, weight loss, and death in many affected birds. Microscopically, the lesions varied in severity. Most affected chicks had severe, locally extensive, ulcerative stomatitis with large amounts of exudate containing numerous bacteria; a smaller number had mild focal lesions with smaller amounts of exudate and bacteria. Although Corynebacterium amycolatum has been consistently isolated from the oral lesions, it was also present in the oral cavity of 34% of normal adult penguins and their chicks and is not known to possess diphtheritic toxins. A primary viral pathogen was therefore suspected, and intracytoplasmic inclusion bodies were occasionally seen in oral mucosal epithelial cells. No herpesvirus DNA was detected with PCR. Avipoxvirus DNA and an unidentified virus-like agent were detected in some early oral lesions, but could not be confirmed in subsequent testing. Electron microscopy on early affected epithelium with intracytoplasmic inclusion bodies was unrewarding. Our findings raise the possibility that the disease is caused by an unknown primary virus infection followed by secondary Corynebacterium invasion, but this requires confirmation. The means of transmission has not been established but insect vectors are suspected.
We examined the carcasses of 148 Black-fronted Terns Sterna albostriata found during the 1998-200... more We examined the carcasses of 148 Black-fronted Terns Sterna albostriata found during the 1998-2000 breeding seasons on the Ohau River, South Island, New Zealand. Predation was the primary cause of mortality of adults, juveniles and chicks, resulting in 47% of all deaths. Video footage showed Feral Cats Felis catus were responsible for 6% of all predator-caused deaths, and physical evidence at carcass remains linked cats to another 19% of predations. Further evidence suggested Norway Rats Rattus norvegicus and Stoats Mustela erminea were responsible for 51% and 6% of predator-caused deaths, respectively. The prey remains left by the different predator species are described. Other causes of mortality included starvation (4%), power lines (1%), road traffic (1%) and various natural causes of mortality (5%). Causes of mortality could not be assigned to 41 % of Black-fronted Terns, but most of these were young chicks that died at the nest soon after hatching. We suggest that predators ar...
International journal of experimental pathology, 1991
The airways of 12 sheep with naturally-occurring allergic airway hypersensitivity, six of which h... more The airways of 12 sheep with naturally-occurring allergic airway hypersensitivity, six of which had changes in both airway resistance and dynamic lung compliance (Group A) and six of which had changes in only dynamic lung compliance (Group B), were compared quantitatively with six non-reacting sheep (Group C) in order to examine the relation between airway hypersensitivity and various morphological features thought to be related to airway hypersensitivity. Compared to the non-reacting sheep (Group C), the hypersensitive sheep (Groups A and B) had a thinner epithelium in medium bronchi and bronchioles, fewer goblet cells in bronchioles, and greater gland area at most airway levels. The differences of the gland dimensions and the types of mucosubstance between hypersensitive and non-reacting animals were more variable. No significant differences between the three groups were noted with regard to luminal occlusion or epithelial sloughing and squamous metaplasia. Although there was a po...
The perinatal development of lymphoid tissue and its associated epithelium in the pharyngeal tons... more The perinatal development of lymphoid tissue and its associated epithelium in the pharyngeal tonsil of sheep was investigated by light and electron microscopy. The lymphoid cells first appeared in the subepithelium in a scattered form at about 92 days gestation. These cells proliferated rapidly during the last trimester of gestation, and had formed many dense aggregates at the time of parturition. At birth, the epithelium overlying the aggregates was extensively infiltrated with lymphocytes and showed early transformation of follicle-associated epithelium. The lymphoid tissue and its associated epithelium did not, however, fully develop until after birth, when well-differentiated follicle-associated epithelium and lymphoid follicles with vigorous lymphopoiesis were present. In 1-2 week old lambs, these structures were ultrastructurally similar to those seen in adult sheep although their size was smaller. The results of this study suggest that the lymphoid tissue of the ovine pharyngeal tonsil and its associated epithelium are morphologically ready to cope with antigens in the extra-uterine environment at birth, but that their full development and maturation are dependent postnatal antigen stimulation.
Megabacteriosis was diagnosed as the cause of depression and wasting in a flock of breeding budge... more Megabacteriosis was diagnosed as the cause of depression and wasting in a flock of breeding budgerigars in the Manawatu. Large numbers of megabacteria were detected in direct smears from mucosal scrapings of the proventriculus of two birds and in the faeces of live birds. The diagnosis was confirmed by demonstrating a chronic proventriculitis histologically associated with megabacterial organisms. Treatment of seven individuals with amphotericin B resulted in clinically sustained weight gain over a 10-week period. Treatment of the whole flock resulted in the resumption of normal condition, behaviour and activity.
HERD HISTORY: A cluster of 19 abortions occurred in April and May 1994 on a seasonal dairy farm o... more HERD HISTORY: A cluster of 19 abortions occurred in April and May 1994 on a seasonal dairy farm of 277 cows in Taranaki. Lesions consistent with neosporosis were seen in several foetuses. The age of the aborting cows ranged from 2 to 12 years. Pregnant rising 2-year-old heifers had been grazed off the main farm on a run-off' until returning in May, when they were replaced on the run-off by the rising l-year-old calves. None of these pregnant heifers aborted. Sera were obtained from all calves (n = 32), 32 of 33 pregnant heifers, 59 of 60 3-4 year-old cows and 101 of 150 older cows, plus all cows that had aborted. Sera were tested using an indirect fluorescent antibody assay. Non-aborting cattle sera were screened at 1:400, and further dilutions were tested from 15 aborted cows. The percentages of seropositive cattle were: 32% of the calves, 3% of the heifers, 31% of the younger cows and 27% of the older cows. The proportion of seropositive heifers was significantly lower (p< 0.01) than in the other age classes. There was no significant difference in the proportion of seropositive animals between these other age classes (p >0.05). Of the 15 cows that aborted, and for which further dilutions were tested, nine had titres of 1: 12,800, four had titres of 1:6400, one had a titre of 1: 1600 and one had a titre of 1:400. Twenty cows were the dams of pregnant heifers. Six of these cows were seropositive but all their offspring were seronegative. Fifteen aborting cows were held over to the following year when 13 became pregnant and calved normally. There were only two to three abortions in the whole herd in this following year. These results suggest that either a point-infection occurred sometime in early 1994 with an infective period short enough so that the heifers did not get infected when they returned to the main farm, or some factor precipitated a recrudescence of latent infection with a subsequent rise in titres in about 29% of the animals on. the main farm only. Although neither hypothesis can be proven or disproven in this observational study, the former hypothesis seems more likely.
The New Zealand sea lion is a threatened species and two unusual events contributed to a decrease... more The New Zealand sea lion is a threatened species and two unusual events contributed to a decrease in recruitment in 2002. The first was a marked reduction (20%) in the number of pups born at the principal Auckland Island rookeries. Secondly, the mortality rate for pups was significantly elevated and was 33% by the end of February, almost three times the mean for that time of the year. Counts of females at rookeries indicated that the lowered fecundity was possibly due to a scarcity of food resources, supported by the fact that male pups (n=50) in 2002 grew poorly with the lightest recorded liveweights for the previous 8 years. Lowered fecundity may also have resulted from infection leading to foetal death, seen in an adult by-catch female, or abortion. Necropsies were conducted on 126/133 pups that died at Sandy Bay and for many the cause of death was multifactorial and included stillbirth, trauma, malnutrition, and severe anaemia caused by hookworm (Uncinaria spp) infection. An unusual disease presentation seen for the first time in 2002 was characterised by systemic bacterial infection that caused suppurative polyarthritis, severe necrotising fasciitis, myositis and osteomyelitis, suppurative peritonitis, pleuritis, or meningitis. For 41 pups, this syndrome was the primary cause of death and for an additional 16 it was a contributing factor along with hookworm infection or trauma. A consistent isolate has been Klebsiella pneumoniae with frequent isolations of Salmonella spp.
Predator identification has traditionally been the domain of ecologists who have relied on the fe... more Predator identification has traditionally been the domain of ecologists who have relied on the feeding sign left by various predator species at the nest or carcass. Thus destructive animals such as cats and dogs can be distinguished from relatively clean predators such as mustelids and messy predators such as possums and rats. The presence of scats or foot imprints, and the location of the nest or carcass are also useful signs, however in many cases it may be impossible to distinguish between predators and scavengers. New technology such as time-lapse photography and video surveillance are valuable tools but still cannot monitor every event. Veterinary pathology can play a useful role by carefully examining and recording the site and severity of lesions and distinguishing between ante- and post mortem tissue damage, using histopathology if necessary. Distances between the canine teeth can be measured from bite marks in the skin and subcutaneous tissues, and mammalian fur on the claws and beak of larger birds can be identified by measuring fibre length and diameter.
To examine the infective dose, incubation period and disease progression of an isolate of Salmone... more To examine the infective dose, incubation period and disease progression of an isolate of Salmonella enterica serotype Typhimurium definitive type 160 (DT160) originating from a naturally-infected house sparrow (Passer domesticus) during an outbreak of the disease in New Zealand. Thirty-six house sparrows captured from the wild and free of Salmonella spp were divided into six groups of six birds, housed individually, and inoculated orally with phosphate buffered saline (PBS) or 10(1), 10(2), 10(3), 10(5), 2 x 10(8) colony forming units (cfu) of the outbreak strain of S. Typhimurium DT160. The birds were observed for 10 days for clinical signs and/or mortality, and faecal samples were collected to determine excretion of S. Typhimurium. The birds were euthanised 11 days post-inoculation (p.i.) and a wide range of tissue samples were collected for histopathological examination, and culture and typing of Salmonella spp. Macro-restriction profiling by pulsed-field gel electrophoresis (PFGE) using XbaI was performed for the epidemiological typing of S. Typhimurium DT160 isolates. Mortality in house sparrows inoculated with S. Typhimurium DT160 was dose-dependent, and 2/6 birds inoculated with 10(5) cfu and all six birds inoculated with 2 x 10(8) cfu died during the study. Infected sparrows displayed few clinical signs, apart from diarrhoea and/or polyuria, fluffed plumage, and sitting on the floor of the cage. Faecal excretion of DT160 occurred briefly in two birds inoculated with 10(2) cfu and four birds inoculated with 10(3) cfu, on most days in five birds inoculated with 10(5) cfu, and continuously in six birds inoculated with 2 x 10(8) cfu. DT160 was isolated from the livers of three birds which received 10(3) cfu, five birds dosed with 10(5) cfu, and all six birds given 2 x 10(8) cfu. Following necropsy, histopathological lesions similar to those seen in the natural disease were observed in the liver or spleen of three birds which received 10(3) cfu, and all birds dosed with > or =10(5) cfu. The results indicate that an isolate of S. Typhimurium DT60 originating from house sparrows in New Zealand is pathogenic to these birds and that the response is dose dependent. The persistence and excretion of the pathogen may last for at least 10 days. This confirms that sparrows infected with DT160 could be a source of infection to humans and other in-contact animals.
To identify risk factors associated with coccidiosis in kiwi (Apteryx spp.) using a retrospective... more To identify risk factors associated with coccidiosis in kiwi (Apteryx spp.) using a retrospective analysis of historical data from kiwi examined post-mortem, and to determine the prevalence of coccidial oocysts in the droppings of wild and captive kiwi. Necropsy reports were examined from kiwi submitted to the National Wildlife Mortality Database of New Zealand (Huia) between February 1977 and May 2011. All cases that reported histological examination of one or more hepatic, intestinal or renal tissues were included in the study (n=372). Data collated for analysis included the presence or absence of coccidiosis in one or more tissues, age, host species, habitat, and season of submission. Fisher's exact test was used to determine the association between each independent variable and the prevalence of coccidiosis. Droppings opportunistically collected from wild and captive kiwi between January 2008 and June 2010 were also examined for the presence of coccidial oocysts. Coccidiosis was evident in 47/372 (12.6%) kiwi examined post-mortem and was considered the primary cause of death in 12/47 (26%) infected cases. Examination of 412 droppings from wild and captive kiwi collected over a 29-month period revealed that 98 (23.8%) samples contained coccidia at the time of sampling. Enteric (n=27) coccidiosis was the most common form diagnosed using histology, followed by renal (n=19) and hepatic (n=11), with splenic (n=2) and pulmonary (n=1) infections infrequently seen. Many kiwi demonstrated infections in multiple tissues. The prevalence of coccidiosis was greater in juvenile kiwi (36/148, 24.3%) than adults (8/133, 6.0%) or chicks (2/83, 2.4%) (p<0.001), although there was no difference in mortality between age groups. Season of year was also associated with overall prevalence (p=0.05), with most cases being diagnosed in the autumn and winter. Coccidiosis was histologically evident in four of five species of kiwi examined, and in all host species upon analysis of droppings. Host species or habitat (captive vs. wild) did not influence the prevalence of disease detected histologically. Age and season were the only factors that influenced the prevalence of coccidiosis in kiwi in this study. Coccidiosis was present in all species of kiwi, and this is the first report of coccidiosis in rowi (Apteryx rowi).
The continued publication of the Journal of Wildlife Diseases depends on the selfless contributio... more The continued publication of the Journal of Wildlife Diseases depends on the selfless contributions of our volunteer peer reviewers. The editors, officers, and members of the Wildlife Disease Association acknowledge and express our sincere appreciation to the following individuals who completed reviews for Volume 53 of the Journal of Wildlife Diseases (reviews completed 1 July 2016–11 July 2017).*
Clinical and laboratory findings in 15 unreported cases of avian cryptococcosis from Australia we... more Clinical and laboratory findings in 15 unreported cases of avian cryptococcosis from Australia were collated and contrasted with 11 cases recorded in the literature. Cryptococcus species produced localized invasive disease of the upper respiratory tract of captive parrots living in Australia. This resulted in signs referable to mycotic rhinitis or to involvement of structures contiguous with the nasal cavity, such as the beak, sinuses, choana, retrobulbar space and palate. Parrots of widely differing ages were affected and of the seven birds for which sex was determinable, six were male. Cryptococcus bacillisporus (formerly C. neoformans var. gattii) accounted for four of five infections in which the species or variety was determinable, suggesting that exposure to eucalyptus material may be a predisposing factor. In these cases, Cryptococcus appeared to behave as a primary pathogen of immunocompetent hosts. One tissue specimen was available from an Australian racing pigeon with mini...
Avian pathology : journal of the W.V.P.A, Jan 6, 2016
We investigated an epidemic mortality cluster of yellow-eyed penguins (Megadyptes antipodes) that... more We investigated an epidemic mortality cluster of yellow-eyed penguins (Megadyptes antipodes) that involved 67 moribund or dead birds found on various beaches of the Otago Peninsula, New Zealand, between January 21 and March 20, 2013. Twenty-four carcases were examined postmortem. Histological lesions of pulmonary, hepatic and splenic erythrophagocytosis and haemosiderosis were found in 23 of 24 birds. Fifteen birds also had haemoglobin-like protein droplets within renal tubular epithelial cells. Despite consistent histological lesions, a cause of death could not be established. Virology, bacteriology and molecular tests for avian influenza, avian paramyxovirus-1, avipoxvirus, Chlamydia psittaci, Plasmodium spp, Babesia spp, Leucocytozoon spp, and Toxoplasma gondii were negative. Tissue concentrations of a range of heavy metals (n = 4 birds) were consistent with low level exposure, while examination of proventricular contents and mucus failed to detect any marine biotoxins or Clostri...
Diphtheritic stomatitis is a seasonal disease that has been recognized as a syndrome in Yellow-ey... more Diphtheritic stomatitis is a seasonal disease that has been recognized as a syndrome in Yellow-eyed Penguin ( Megadyptes antipodes ) chicks in New Zealand for >10 yr. It was present in about 50% of 234 chicks examined since 2002 and is characterized by a thick serocellular exudate in the oral cavity of 1-4-wk-old chicks. The syndrome includes inanition, weight loss, and death in many affected birds. Microscopically, the lesions varied in severity. Most affected chicks had severe, locally extensive, ulcerative stomatitis with large amounts of exudate containing numerous bacteria; a smaller number had mild focal lesions with smaller amounts of exudate and bacteria. Although Corynebacterium amycolatum has been consistently isolated from the oral lesions, it was also present in the oral cavity of 34% of normal adult penguins and their chicks and is not known to possess diphtheritic toxins. A primary viral pathogen was therefore suspected, and intracytoplasmic inclusion bodies were occasionally seen in oral mucosal epithelial cells. No herpesvirus DNA was detected with PCR. Avipoxvirus DNA and an unidentified virus-like agent were detected in some early oral lesions, but could not be confirmed in subsequent testing. Electron microscopy on early affected epithelium with intracytoplasmic inclusion bodies was unrewarding. Our findings raise the possibility that the disease is caused by an unknown primary virus infection followed by secondary Corynebacterium invasion, but this requires confirmation. The means of transmission has not been established but insect vectors are suspected.
We examined the carcasses of 148 Black-fronted Terns Sterna albostriata found during the 1998-200... more We examined the carcasses of 148 Black-fronted Terns Sterna albostriata found during the 1998-2000 breeding seasons on the Ohau River, South Island, New Zealand. Predation was the primary cause of mortality of adults, juveniles and chicks, resulting in 47% of all deaths. Video footage showed Feral Cats Felis catus were responsible for 6% of all predator-caused deaths, and physical evidence at carcass remains linked cats to another 19% of predations. Further evidence suggested Norway Rats Rattus norvegicus and Stoats Mustela erminea were responsible for 51% and 6% of predator-caused deaths, respectively. The prey remains left by the different predator species are described. Other causes of mortality included starvation (4%), power lines (1%), road traffic (1%) and various natural causes of mortality (5%). Causes of mortality could not be assigned to 41 % of Black-fronted Terns, but most of these were young chicks that died at the nest soon after hatching. We suggest that predators ar...
International journal of experimental pathology, 1991
The airways of 12 sheep with naturally-occurring allergic airway hypersensitivity, six of which h... more The airways of 12 sheep with naturally-occurring allergic airway hypersensitivity, six of which had changes in both airway resistance and dynamic lung compliance (Group A) and six of which had changes in only dynamic lung compliance (Group B), were compared quantitatively with six non-reacting sheep (Group C) in order to examine the relation between airway hypersensitivity and various morphological features thought to be related to airway hypersensitivity. Compared to the non-reacting sheep (Group C), the hypersensitive sheep (Groups A and B) had a thinner epithelium in medium bronchi and bronchioles, fewer goblet cells in bronchioles, and greater gland area at most airway levels. The differences of the gland dimensions and the types of mucosubstance between hypersensitive and non-reacting animals were more variable. No significant differences between the three groups were noted with regard to luminal occlusion or epithelial sloughing and squamous metaplasia. Although there was a po...
The perinatal development of lymphoid tissue and its associated epithelium in the pharyngeal tons... more The perinatal development of lymphoid tissue and its associated epithelium in the pharyngeal tonsil of sheep was investigated by light and electron microscopy. The lymphoid cells first appeared in the subepithelium in a scattered form at about 92 days gestation. These cells proliferated rapidly during the last trimester of gestation, and had formed many dense aggregates at the time of parturition. At birth, the epithelium overlying the aggregates was extensively infiltrated with lymphocytes and showed early transformation of follicle-associated epithelium. The lymphoid tissue and its associated epithelium did not, however, fully develop until after birth, when well-differentiated follicle-associated epithelium and lymphoid follicles with vigorous lymphopoiesis were present. In 1-2 week old lambs, these structures were ultrastructurally similar to those seen in adult sheep although their size was smaller. The results of this study suggest that the lymphoid tissue of the ovine pharyngeal tonsil and its associated epithelium are morphologically ready to cope with antigens in the extra-uterine environment at birth, but that their full development and maturation are dependent postnatal antigen stimulation.
Megabacteriosis was diagnosed as the cause of depression and wasting in a flock of breeding budge... more Megabacteriosis was diagnosed as the cause of depression and wasting in a flock of breeding budgerigars in the Manawatu. Large numbers of megabacteria were detected in direct smears from mucosal scrapings of the proventriculus of two birds and in the faeces of live birds. The diagnosis was confirmed by demonstrating a chronic proventriculitis histologically associated with megabacterial organisms. Treatment of seven individuals with amphotericin B resulted in clinically sustained weight gain over a 10-week period. Treatment of the whole flock resulted in the resumption of normal condition, behaviour and activity.
HERD HISTORY: A cluster of 19 abortions occurred in April and May 1994 on a seasonal dairy farm o... more HERD HISTORY: A cluster of 19 abortions occurred in April and May 1994 on a seasonal dairy farm of 277 cows in Taranaki. Lesions consistent with neosporosis were seen in several foetuses. The age of the aborting cows ranged from 2 to 12 years. Pregnant rising 2-year-old heifers had been grazed off the main farm on a run-off' until returning in May, when they were replaced on the run-off by the rising l-year-old calves. None of these pregnant heifers aborted. Sera were obtained from all calves (n = 32), 32 of 33 pregnant heifers, 59 of 60 3-4 year-old cows and 101 of 150 older cows, plus all cows that had aborted. Sera were tested using an indirect fluorescent antibody assay. Non-aborting cattle sera were screened at 1:400, and further dilutions were tested from 15 aborted cows. The percentages of seropositive cattle were: 32% of the calves, 3% of the heifers, 31% of the younger cows and 27% of the older cows. The proportion of seropositive heifers was significantly lower (p< 0.01) than in the other age classes. There was no significant difference in the proportion of seropositive animals between these other age classes (p >0.05). Of the 15 cows that aborted, and for which further dilutions were tested, nine had titres of 1: 12,800, four had titres of 1:6400, one had a titre of 1: 1600 and one had a titre of 1:400. Twenty cows were the dams of pregnant heifers. Six of these cows were seropositive but all their offspring were seronegative. Fifteen aborting cows were held over to the following year when 13 became pregnant and calved normally. There were only two to three abortions in the whole herd in this following year. These results suggest that either a point-infection occurred sometime in early 1994 with an infective period short enough so that the heifers did not get infected when they returned to the main farm, or some factor precipitated a recrudescence of latent infection with a subsequent rise in titres in about 29% of the animals on. the main farm only. Although neither hypothesis can be proven or disproven in this observational study, the former hypothesis seems more likely.
The New Zealand sea lion is a threatened species and two unusual events contributed to a decrease... more The New Zealand sea lion is a threatened species and two unusual events contributed to a decrease in recruitment in 2002. The first was a marked reduction (20%) in the number of pups born at the principal Auckland Island rookeries. Secondly, the mortality rate for pups was significantly elevated and was 33% by the end of February, almost three times the mean for that time of the year. Counts of females at rookeries indicated that the lowered fecundity was possibly due to a scarcity of food resources, supported by the fact that male pups (n=50) in 2002 grew poorly with the lightest recorded liveweights for the previous 8 years. Lowered fecundity may also have resulted from infection leading to foetal death, seen in an adult by-catch female, or abortion. Necropsies were conducted on 126/133 pups that died at Sandy Bay and for many the cause of death was multifactorial and included stillbirth, trauma, malnutrition, and severe anaemia caused by hookworm (Uncinaria spp) infection. An unusual disease presentation seen for the first time in 2002 was characterised by systemic bacterial infection that caused suppurative polyarthritis, severe necrotising fasciitis, myositis and osteomyelitis, suppurative peritonitis, pleuritis, or meningitis. For 41 pups, this syndrome was the primary cause of death and for an additional 16 it was a contributing factor along with hookworm infection or trauma. A consistent isolate has been Klebsiella pneumoniae with frequent isolations of Salmonella spp.
Predator identification has traditionally been the domain of ecologists who have relied on the fe... more Predator identification has traditionally been the domain of ecologists who have relied on the feeding sign left by various predator species at the nest or carcass. Thus destructive animals such as cats and dogs can be distinguished from relatively clean predators such as mustelids and messy predators such as possums and rats. The presence of scats or foot imprints, and the location of the nest or carcass are also useful signs, however in many cases it may be impossible to distinguish between predators and scavengers. New technology such as time-lapse photography and video surveillance are valuable tools but still cannot monitor every event. Veterinary pathology can play a useful role by carefully examining and recording the site and severity of lesions and distinguishing between ante- and post mortem tissue damage, using histopathology if necessary. Distances between the canine teeth can be measured from bite marks in the skin and subcutaneous tissues, and mammalian fur on the claws and beak of larger birds can be identified by measuring fibre length and diameter.
To examine the infective dose, incubation period and disease progression of an isolate of Salmone... more To examine the infective dose, incubation period and disease progression of an isolate of Salmonella enterica serotype Typhimurium definitive type 160 (DT160) originating from a naturally-infected house sparrow (Passer domesticus) during an outbreak of the disease in New Zealand. Thirty-six house sparrows captured from the wild and free of Salmonella spp were divided into six groups of six birds, housed individually, and inoculated orally with phosphate buffered saline (PBS) or 10(1), 10(2), 10(3), 10(5), 2 x 10(8) colony forming units (cfu) of the outbreak strain of S. Typhimurium DT160. The birds were observed for 10 days for clinical signs and/or mortality, and faecal samples were collected to determine excretion of S. Typhimurium. The birds were euthanised 11 days post-inoculation (p.i.) and a wide range of tissue samples were collected for histopathological examination, and culture and typing of Salmonella spp. Macro-restriction profiling by pulsed-field gel electrophoresis (PFGE) using XbaI was performed for the epidemiological typing of S. Typhimurium DT160 isolates. Mortality in house sparrows inoculated with S. Typhimurium DT160 was dose-dependent, and 2/6 birds inoculated with 10(5) cfu and all six birds inoculated with 2 x 10(8) cfu died during the study. Infected sparrows displayed few clinical signs, apart from diarrhoea and/or polyuria, fluffed plumage, and sitting on the floor of the cage. Faecal excretion of DT160 occurred briefly in two birds inoculated with 10(2) cfu and four birds inoculated with 10(3) cfu, on most days in five birds inoculated with 10(5) cfu, and continuously in six birds inoculated with 2 x 10(8) cfu. DT160 was isolated from the livers of three birds which received 10(3) cfu, five birds dosed with 10(5) cfu, and all six birds given 2 x 10(8) cfu. Following necropsy, histopathological lesions similar to those seen in the natural disease were observed in the liver or spleen of three birds which received 10(3) cfu, and all birds dosed with > or =10(5) cfu. The results indicate that an isolate of S. Typhimurium DT60 originating from house sparrows in New Zealand is pathogenic to these birds and that the response is dose dependent. The persistence and excretion of the pathogen may last for at least 10 days. This confirms that sparrows infected with DT160 could be a source of infection to humans and other in-contact animals.
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