Mycotic disease in the common New Zealand gecko (Hoplodactylus maculatus)

Two adult female geckoes (Hoplodactylus maculatus) from the National Wildlife Centre, Mt Bruce, Masterton, died within the period of a month and were presented to the Department of Veterinary Pathology and Public Health at Massey University for necropsy. The first gecko had numerous 1-2 mm diameter punctate ulcers of the skin over the ventral and dorsal regions of the body. The second animal had slight discolouration of some of the scales. Skin swabs were taken from each case for culture. There were no other gross lesions apparent at necropsy. Histologically, the only lesions in the first gecko were areas of epidermal and dermal ulceration involving fungi and bacteria. In the second gecko, there was limited inflammation in the skin, but in the lungs there was necrosis of the pulmonary septae and constituent muscle bundles caused by fungi whose septate mycelia extended into adjacent large blood vessels and caused mycotic thrombi; hyphae were also found in the spleen and liver. Paecilomyces sp. septate fungus was recovered from both geckoes and Pseudomonas spp. and a mixed Gram-negative flora were recovered from the cutaneous lesions on culture. The death of the first gecko was considered to be due to widespread ulcerative dermatitis, while that of the second gecko was thought to be due to mycotic pneumonitis and mycotic septicaemia. It is believed that environmental factors, such as cold temperature and high humidity, contributed to a reduction in the immune response in the affected geckoes, with the consequent development of overwhelming fungal infections.     

Mycotic disease in the common New Zealand gecko (Hoplodactylus maculatus)

Two adult female geckoes (Hoplodacrylus maculatus) from the National Wildlife Centre, Mt Bruce, Masterton, died within 1 month and were presented for necropsy. The first gecko had numerous punctate ulcers, 1–2 mm in diameter, over ventral and dorsal regions of the skin. The second animal was seen to have widespread variable discolouration of epidermal scales. Swabs were taken from the skin of each case for culture. There were no other gross lesions apparent on necropsy. On histological examination of the first gecko, there were areas of epidermal and dermal ulceration containing mycelia and bacteria, while in the second gecko there were lung lesions including necrosis of the pulmonary septa and constituent muscle bundles caused by fungi whose septate mycelia extended into adjacent large blood vessels causing thrombi. Hyphae were also found in the spleen and liver. Paecilomyces sp. septate fungi were recovered from both geckoes and Pseudomonas spp. and a mixed Gram-negative flora were recovered from the cutaneous lesions. The death of the first gecko was considered to be due to widespread ulcerative dermatitis while that of the second gecko was thought to be due to mycotic pneumonitis and mycotic septicaemia.     

Ovariectomy as treatment for ovarian bacterial granulomas in a Duvaucel's gecko (Hoplodactylus duvaucelii)

CASE HISTORY: An adult female Duvaucel's gecko (Hoplodactylus duvaucelii) from a threatened species breeding programme presented due to a prolonged gestation period and distended abdomen.

CLINICAL AND PATHOLOGICAL FINDINGS: The gecko was in lean body condition with an irregularly shaped, firm mass in the coelomic cavity. Radiographically there was a diffuse radio-opacity within the coelomic cavity with cranial displacement of the right lung field. Ultrasonography revealed a round homogenous abdominal mass of medium echogenicity with an echogenic capsule. Haematology showed a leucocytosis with a moderate left shift in heterophils and toxic changes. Bilateral ovariectomy was performed to remove two ovarian granulomas and Salmonella enterica subspecies houtenae (IV) was cultured from the ovarian tissue. The gecko recovered well from the surgery, regained weight and remained in good health 3 years following the surgery.

DIAGNOSIS: Pre-ovulatory stasis and ovarian granulomas associated with infection with Salmonella enterica subsp. houtenae.

CLINICAL RELEVANCE: The surgery described in this case resulted in recovery of the gecko, which despite its loss of reproductive capability is of value as an education animal. This is the first report of pre-ovulatory stasis and ovarian granulomas associated with infection with Salmonella enterica in a Duvaucel's gecko and is also the first reported case of pre-ovulatory stasis in a viviparous lizard species. The case adds to knowledge regarding potential reproductive pathology in lizards, which is particularly important information for managers of captive lizard breeding programmes.     

Theileria orientalis, a blood parasite of cattle. First report in New Zealand

A Theileria sp. piroplasm has been found in cattle from 10 Northland herds. Transmission studies, involving two splenectomized calves, led to its identification as T. orientalis, which has not been previously found in New Zealand. This piroplasm is relatively benign hut can cause severe anaemia in heavily parasitized animals. The cattle tick Haemaphysalis longicornis is considered to be the likely vector.     

Theileria orientalis,a blood parasite of cattle. first report in New Zealand

A Theileria sp. piroplasm has been found in cattle from 10 Northland herds. Transmission studies, involving two splenectomized calves, led to its identification as T. orientalis, which has not been previously found in New Zealand. This piroplasm is relatively benign, but can cause severe anaemia in heavily parasitized animals. The cattle tick Haemaphysalis longicornis is considered to be the likely vector.     

A survey of anthelmintic use and internal parasite control in farmed deer in New Zealand

AIM: To survey parasite control programmes and anthelmintic usage over a 12-month period on deer farms in New Zealand. METHODS: A questionnaire of general farm data, policy and procedures for anthelmintic use, anthelmintic programmes for weaner and older deer, general information and understanding of parasite management practices was posted to 500 deer farmers in November 2004. RESULTS: Two hundred and twenty-seven (45.4%) replies were received, and 198 (39.6%) were suitable for analysis. Ninety four percent of respondents used anthelmintics at least once in the 12-month period; 53% treated all classes of deer and 22% treated only weaners. Seventy-four percent based anthelmintic dose on weight of the heaviest animal, and 36% used a weigh scale. Weaner deer (n=175 farms) were treated 1-13 (mean 3.2) times in their first 12 months, at the earliest commencing in January and at the latest in November. The mean interval between treatments ranged from 41 to 46 days. Yearling and adult hinds and stags were treated at least once (range 1-7 times) on 55-64% of farms, depending on class of animal. Moxidectin was the anthelmintic most commonly used (46-58%, depending on class of animal), followed by abamectin, eprinomectin, oxfendazole, ivermectin, albendazole, levamisole and doramectin. Perceived efficacy was the most common reason for choosing a type of anthelmintic. Weight gain and body condition were the most common measures used for monitoring parasitism in weaners and older deer, respectively, and few respondents used faecal egg and/or larval counts. Coughing and/or scouring were associated with parasitism in weaners on 13-14% of farms, and deaths associated with lungworm and gastrointestinal parasites were recorded on 5% and 3% of farms, respectively. Veterinary input to diagnosis was involved in 23% of events. Production losses and/or death of yearling and/or adult deer due to parasitism were reported by 27% of respondents. When planning anthelmintic treatment programmes, 63% of respondents followed advice from veterinarians. Thirty four percent always placed deer on clean or spelled pastures after treatment, while 32% did that often. Fifteen percent had incorporated forages and/or herbs with assumed anthelmintic properties into their parasite control programme. Forty-four percent were very confident of a return on investment when using anthelmintics for their deer. Respondents stated that their knowledge of the life cycle of the major parasites of deer was very good (8%), reasonably good (61%), poor (28%), or nil (3%). CONCLUSION: Anthelmintics are used on almost all deer farms, and practices and programmes vary considerably. Opportunities exist for veterinarians to assist deer farmer clients to improve their parasite control programmes.     

Equine hydatidosis: a new record for New Zealand

Cysts found in the liver of a horse which had never been out of New Zealand were used to infect two dogs which were slaughtered 35 days after infection. Large numbers of Echinococcus granulosus were recovered. These cestodes were compared with mature dog-sheep cestodes, using light and scanning electron microscopy and identified as the dog-horse strain of E.granulosus.     

Routine blood values for New Zealand brushtail possums at capture

Abstract

Extract

Thank you for the opportunity to reply to Dr Clark's and Ms Cooke's recent letters. As stated in our original letter “Routine blood values for New Zealand brushtail possums (Trichosurus vulpecula) at capture”, the brushtail possum is the subject of intense and diverse study throughout the country (Lynch, 1997 Lynch, R, ed. 1997. “Biological Control of Possums”. In Workshop Report. The Royal Society of New Zealand, Miscellaneous Series 45, Wellington: Royal Society of New Zealand.  [Google Scholar]). Part of this study focuses on finding disease agents that may be useful in biological control. At present there are no publications detailing the blood values one might expect to find in a non-diseased, wild New Zealand possum at capture. As noted in our letter, we have not set out to find absolute normal values, rather those blood values an investigator might expect to find in a healthy possum presented with little or no history by a member of the public immediately following capture (hence the use of the word “routine” in the title rather than “normal”).     

Crypt abscesses in the caeca of feral rabbits in a rabbit haemorrhagic disease endemic region of New Zealand

AIM: To describe the pathology of crypt abscesses in the caeca of feral rabbits in the Manawatu region of New Zealand, and to examine the possible relationship between their prevalence and rabbit haemorrhagic disease (RHD) virus (RHDV) infection.

METHODS: During the course of a 3-year study of RHD, 173 wild rabbits (Oryctolagus cuniculus) were shot on three pastoral livestock farms in the Manawatu region of New Zealand. All rabbits were necropsied, and tissue samples of the caeca were examined histologically. The age of each animal was determined, and blood samples collected for the detection of RHDV antibodies. Logistic regression was used to model the odds of rabbits having crypt abscesses.

RESULTS: At necropsy, 63/173 (36.4%) rabbits were found to have small circular black nodules on the mucosal surface of their appendix caecum and/or sacculus rotundus. Microscopically, these were identified as small crypt abscesses composed of dilated sacs at the base of the mucosa that were often lined by a thin layer of attenuated epithelial cells. They usually contained large amounts of concentrically-laminated mucopolysaccharide material that was sometimes pigmented, inflammatory debris, and were often the site of a moderate multifocal appendicitis. Although RHDV was active in the study area, no association was found between RHDV antibodies in serum and the presence of lesions. The lesions were more common in older individuals and those born in summer or autumn.

CONCLUSIONS: This is the first report of crypt abscesses with inflammation and necrotic debris in the caeca of rabbits. No association between the occurrence of crypt abscesses and RHDV infection was identified. Wild rabbits born in a particular season were presumably exposed very early in life to conditions that caused the crypt abscesses to develop. Alternatively, association with season of birth may represent rabbits that were of similar age in a later stage of their lives, when they became exposed to the cause of the lesions, which remains unidentified.     

Crypt abscesses in the caeca of feral rabbits in a rabbit haemorrhagic disease endemic region of New Zealand

AIM: To describe the pathology of crypt abscesses in the caeca of feral rabbits in the Manawatu region of New Zealand, and to examine the possible relationship between their prevalence and rabbit haemorrhagic disease (RHD) virus (RHDV) infection. METHODS: During the course of a 3-year study of RHD, 173 wild rabbits (Oryctolagus cuniculus) were shot on three pastoral livestock farms in the Manawatu region of New Zealand. All rabbits were necropsied, and tissue samples of the caeca were examined histologically. The age of each animal was determined, and blood samples collected for the detection of RHDV antibodies. Logistic regression was used to model the odds of rabbits having crypt abscesses. RESULTS: At necropsy, 63/173 (36.4%) rabbits were found to have small circular black nodules on the mucosal surface of their appendix caecum and/or sacculus rotundus. Microscopically, these were identified as small crypt abscesses composed of dilated sacs at the base of the mucosa that were often lined by a thin layer of attenuated epithelial cells. They usually contained large amounts of concentrically-laminated mucopolysaccharide material that was sometimes pigmented, inflammatory debris, and were often the site of a moderate multifocal appendicitis. Although RHDV was active in the study area, no association was found between RHDV antibodies in serum and the presence of lesions. The lesions were more common in older individuals and those born in summer or autumn. CONCLUSIONS: This is the first report of crypt abscesses with inflammation and necrotic debris in the caeca of rabbits. No association between the occurrence of crypt abscesses and RHDV infection was identified. Wild rabbits born in a particular season were presumably exposed very early in life to conditions that caused the crypt abscesses to develop. Alternatively, association with season of birth may represent rabbits that were of similar age in a later stage of their lives, when they became exposed to the cause of the lesions, which remains unidentified.     

Fascioliasis in New Zealand: A review

Intermediate hosts of Fasciola hepatica in New Zealand are the native species Lymnaea tomentosa, and introduced species, L. columella and L. truncatula. The latter is of little significance in New Zealand. Fascioliasis has become more widespread since 1950 following colonisation of much of the North Island by L. columella. L. tomentosa can produce eggs at 5°C and L. columella at 2°C. L. columella produces about the three times as many eggs as L. tomentosa and the eggs of the former develop more rapidly and over a wider range of temperatures. Both species inhabit ponds and marshes, although L. columella is better suited to pond habitats. Neither species will survive in marsh habitats that dry out in summer. Both species tolerate wide ranges of Ca and Mg concentrations and pH. Marsh habitats of the two species are indistinguishable though there is evidence of subtle differences in habitat preferences. Snail populations are minimal in winter and fluctuate irregularly throughout the rest of the year. In general, L. tomentosa populations contain proportionally more mature snails than those of L. columella. The epidemiology of fascioliasis in New Zealand is discussed. The absence of outbreaks of acute disease, the multiplicity of snail hosts and variations in climate pose problems for investigators. Overwintering infections of snails have been observed in L. tomentosa, but not in L. columella. With the latter host, transmission of Fasciola occurred over 6–7 months from mid-summer to mid-winter.The rate of infection of tracer sheep over 5 years varied but was not related to temperature or increased summer rainfall. Infection rates tended to increase when summers were dry and animals forced to graze the snails habitats. Rates in infection were not related to snail densities but to the numbers of mature snails on habitats. The infection rate of L. columella was extremely low ($\text{1}\text{790}$ snails examined). Sheep appear to be more important than cattle in maintaining Fasciolainfections from year to year. The control of fascioliasis is discussed briefly. It is argued that prevention of infection is preferable to removing infections already acquired, and low this might be achieved by a strategic anthelmintic treatment when L. columella is involved is described. Further studies on the prevalence and epidemiology of fascioliasis in New Zealand are required.     

A review of veterinary practice in New Zealand

Extract

The development of veterinary practice in New Zealand over the past thirty years has been phenomenal. I have been engaged in practice and to some extent involved with this development during this time. Perhaps by stopping to look at where we are, where we have come from, and how, we may help to guide future development.