Diseases in Little has been documented about the New Zealand reptiles diseases found in New Zealand reptiles, but with the burgeoning Introduction interest in wildlife and conservation The only native reptiles New Zealand has are tuatara and lizards. world-wide there is a renewed Two types of sea-snake and five types of marine turtle are impetus to describe them and occasionally found in our waters but these are unlikely to breed here rank their significance. and are not considered native.
Tuatara: There are two species of tuatara, Sphenodon punctatus and Caroline Twentyman S guntheri, both in the Order Sphenodontida.
Lizards: There are two families of lizard, the Gekkonidae and the Salmonella are commonly isolated from such infections(2). Viruses Scincidae, both in the Order Squamata(1). These comprise 16 known and fungi may also be involved. If left untreated, infectious types of gecko and 28 known types of skink, but this number is likely stomatitis may cause death through starvation or systemic to increase as more research is done. involvement. Geckos are in two groups: grey-brown geckos (Hoplodactylus), which ‘Black Spot’: This skin disease has been reported in both wild and come out at night and have skin which changes between pale and captive New Zealand geckos(3). It has been seen only in winter and dark, and green geckos (Naultinus), which are active by day and manifests as a general blackening between the scales. The cannot alter their skin colour(1). discolouration spreads and affected lizards become depressed and Our native skinks are in two genera: the Oligosoma (formerly anorexic, lose weight, and become dehydrated. They become Leiolopisma), which tend to have shallow and pointed heads, bodies progressively weaker, their normal sloughing cycle is disrupted, and that are oval in cross-section, and comparatively long limbs and toes; they die after several months. The fungus Cladosporium and the Cyclodina which tend to have deeper and blunter heads, cladosporioides seems to be the usual causal agent but the fungus bodies more square in cross-section, and comparatively short limbs Alternaria alternata may also be involved. The disease may occur in and toes(1). damp, cold, and overcrowded conditions, or when there are other types of stress(3). Infectious disease Other mycotic infections: Two common New Zealand geckos Salmonellosis: Several Salmonella serotypes have been isolated from (Hoplodactylus maculatus) died with fungal infections of the skin New Zealand geckos, particularly green geckos. These serotypes and with variable involvement of the lungs, other viscera, and blood include S Hindmarsh, S Typhimurium, S Victoria, S Saintpaul, S vessels(4). Paecilomyces fungi were recovered from the skin of both Mississippi, and S Wohlen (M. Vickers, pers. comm.). Salmonella geckos. Their internal organs were not cultured for fungi or bacteria, have been grown from various organs (particularly the liver) of but the fungal hyphae seen in the skin lesions were indistinguishable geckos which have died with signs such as depression, anorexia, histologically from those seen in the lung lesions. Gram negative vomiting, lethargy, wasting, respiratory distress, abortion, nervous bacteria, including Pseudomonas, were grown from the skin of both signs and sudden death. Salmonella species from reptiles pose a geckos. Cold temperatures and high humidity were thought to have zoonotic risk, and outbreaks in humans in New Zealand have been suppressed the immune response in the affected geckos, with the traced back to reptiles(2). consequent development of overwhelming fungal infections(4). There may be a geographical pattern of Salmonella serotypes in the Other types of gecko have been similarly affected. wild, with certain serotypes in geckos appearing to predominate in Several captive tuatara from one location experienced chronic particular areas (Mark Vickers, pers. comm.). If lizards from anorexia, wasting, dehydration, skin discolouration, and a different areas are mixed whilst in captivity then lizards carrying disturbance in the normal skin shedding process. At least four of the Salmonella specific go one area may infect naïve lizards from tuatara died, but two recovered after fluid, antibiotic, and topical another. In certain conditions these infections can become antifungal treatment. Necropsies demonstrated a severe mycotic pathogenic, so there is great potential risk if naïve captive reptiles dermatitis, but the species of fungus has not yet been identified. This were to be released back into the wild after association with carrier disease may be the same or similar to ‘Black Spot’. All the affected animals. tuatara had a history of environmental stress involving a period of Infectious stomatitis: ‘Mouth Rot’ usually occurs secondary to stress altered husbandry which included a reduced exposure to natural UV caused by husbandry or management problems e.g. overcrowding, light. Stress is thought to have compromised the immune system and low ambient temperatures, poor nutrition(2). Fighting may also be resulted in opportunistic mycotic infections. an initiating factor. Pseudomonas, Aeromonas, Klebsiella, and 3.
page 3 Surveillance 26(4) 1999 Reproductive disease have been recorded on tuatara(7). The mites are visible as small red or Foetal mummification: This has been reported to occur as a result orange spots usually clustered around the eye, ear, axilla, groin, or of a disturbance in the normal parturition/seasonal trigger in geckos cloaca – where the skin is folded and relatively thin(8). Some mites that originate from the South Island and Stewart Island (M. Vickers, suck blood. They may cause skin damage and/or death. Mites appear pers. comm.). to be of particular importance in skinks (M. Vickers, pers. comm.). Ticks are difficult to see on tuatara because they are the same colour Dystocia: All of our native geckos give birth to live young, as do as the scales and look like part of the wrinkled skin(9). most of our skinks (the native Leiolopisma suteri and the introduced Lampropholis delicata lay eggs)(5). Tuatara lay eggs. Dystocias have Internal parasites been reported. These may be obstructive, when there is an inability Nematodes: A variety of nematodes have been found in New to pass eggs or foetuses, or non-obstructive(2). The latter have been Zealand skinks (Hedruris minuta, Skrjabinodon trimorphi, attributed to several possible causes including husbandry problems Skrjabinodon sp, Ascarid, and Spiurid larvae), and one in tuatara such as improper nesting site, improper temperature, malnutrition, (Hatterianema hollandiae)(7). Clinical signs of infection can include and dehydration(2). Poor physical condition may also contribute. anorexia, anaemia, regurgitation, bloat, signs of obstruction, and Lizards with dystocia rapidly become depressed and unresponsive. wasting(2). Peritonitis may result if the condition is unresolved. Trematodes: Two types of trematode have been identified in New Ill-thrift after oxytocin administration: Significant weight loss and Zealand skinks (Dolichosaccus leiolopismae and Paradistomum dehydration occurred in a female tuatara from Hamilton Zoo after pacificus), one in New Zealand geckos (P pacificus), and one in oxytocin injections were administered to induce laying(6). This was tuatara (D leiolopismae)(7). thought to have occurred as a stress response to the repeat-oxytocin induction and consequent double episode of egg-laying. The stress Cestodes: Three types of cestode have been found in New Zealand may have been exacerbated by subsequent peer aggression. The skinks (Ochoristica novaezealandiae, Baerietta decidua, and condition resolved after treatment(6). B allisonae) and one in geckos (B allisonae). Acanthocephala: Larvae belonging to this Phylum have been found Nutritional disease in New Zealand skinks. Osteodystrophy: This has been reported in five of a litter of skinks Protozoa: Several types of protozoa have been found in New (M. Vickers, pers. comm.). The animals developed spinal lumps in Zealand skinks (Hepatozoon lygosomarum and Plasmodium the lumbar region, with associated paresis/paralysis affecting the tail lygosomae) and geckos (H lygosomarum, Eimeria, Entamoeba sp, and hind legs. The condition was secondary to a calcium- Nyctotherus sp, and Trichomonas hoplodactylus), and one in tuatara phosphorus imbalance. Metabolic bone diseases may also occur in (Haemogregarina tuatarae)(7). Also found in a 40-plus-year-old reptiles on diets low in vitamin D3. Reptiles should have exposure to captive tuatara have been large numbers of intra-myocytic, acellular unfiltered sunlight or appropriate artificial UV sources(2). protozoa - probably Microsporidium sp – in skeletal muscle and Gout: Both articular and visceral gout have been reported in tongue(10). In some of the affected areas there was severe (2) reptiles . Theories on aetiology include inappropriate dietary granulomatous inflammation. The haemoparasitic protozoa of (2) protein levels and dehydration . reptiles in most instances produce no discernible clinical disease(2). Cachexia: This may result from stress-induced failure to eat, All require invertebrates as intermediate hosts. provision of too little food, inappropriate foods or feeding Miscellaneous diseases management, and diseases that affect appetite and metabolism(2). Debilitation occurs with long-term starvation(2). Dysecdysis: Improper skin shedding is a symptom of a problem and not a primary problem(2). In skinks and tuatara the skin is normally Obesity: This may interfere with mating. It has been recorded in shed piecemeal, while geckos usually slough it in one piece(9). tuatara. Dysecdysis is commonly associated with an excessively dry Parasitic disease environment, old injuries, malnutrition, external parasitism, or dermatitis(2). External parasites Heat stress: This can cause death in captive tuatara(11). Mites: Three species of mite have been recorded on New Zealand skinks (Neotrombicula sphenodonti, Ophionyssus scincorum, and Trauma: This may occur during fighting between animals. All New Acomatocarus lygosomae); and six species of mites on New Zealand Zealand lizards and tuatara are able to shed their tails (autotomy) as geckos (N sphenodonti, N naultini, O galeotes, Geckobia haplodactyli, a means of escaping from predators(8). The stump heals quickly and G naultina and Microtrombicula hoplodactyli). One species of mite the lost portion is re-grown, but it will differ in colour and pattern (N sphenodonti), and one species of tick (Aponomma sphenodonti) from the original. Rodent bites can cause tail amputation(2).
page 4 Surveillance 26(4) 1999 Acknowledgements (5) Gill BJ. Collins Handguide to the frogs and reptiles of New Zealand, The author would like to thank Mark Vickers, Barbara Blanchard, Pp 26 & 50. William Collins Publishers Limited, Auckland, New Zealand, 1986. Lindsay Hazley and Alison Cree for supplying information, and (6) Goold M. Tuatara - Ill-thrift post oxytocin induced egg laying. Kokako 4(3), Alastair Johnstone for use of material from the pathology registry, 3-4, 1997. Massey University. The Department of Conservation and Massey (7) Ainsworth R. Parasites of NZ reptiles, poster paper for the Second World University provided access to material from Huia – the National Congress of Herpetology, Adelaide,29 Dec 1993-6 Jan 1994. Wildlife Mortality Database – and Alpha Scientific Ltd also made (8) Robb J. New Zealand amphibians & reptiles. William Collins Publishers Ltd, case material available. Auckland, New Zealand, 1980. (9) Sharell R. The tuatara, lizards and frogs of New Zealand. Collins, London, UK, References 1966. (1) Gill BJ, Whitaker AH. New Zealand Frogs and Reptiles. David Bateman Limited, (10) Orr M. Animal Health Laboratory Network, Review of diagnostic cases - Albany, New Zealand, 1996. January to March 1995. Surveillance 22(2), 5, 1995. (2) Mader DR. Reptile Medicine and Surgery, WB Saunders, 1996. (11) Boardman WS, Sibley MD. The captive management, diseases and veterinary (3) McCall PG. Studies on “Black Spot”, a skin disease of New Zealand geckos. care of tuatara. In: Proceedings of the American Association of Zoo Thesis for Bachelor of Science (Honours) in Microbiology. Massey University, Veterinarians, 1999. 1981. Caroline Twentyman (4) Cork SC, Stockdale PHG. Mycotic disease in the common New Zealand gecko Institute of Veterinary, Animal and Biomedical Sciences (Hoplodactylus maculatus). New Zealand Veterinary Journal 42, 144-147, Massey University, Palmerston North 1994. Email: [email protected]
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