Spatial epidemiology of the Asian honey bee mite (Varroa destructor) in the North Island of New Zealand

We describe the spatial epidemiology of Varroa destructor infestation among honey bee apiaries in the greater Auckland area of the North Island of New Zealand. The study population was comprised of 641 apiaries located within the boundaries of the study area on 11 April 2000. Cases were those members of the study population declared Varroa-infested on the basis of testing conducted between April and June 2000. The odds of Varroa was highest in apiaries in the area surrounding transport and storage facilities in the vicinity of Auckland International Airport. A mixed-effects geostatistical model, accounting for spatial extra-binomial variation in Varroa prevalence, showed a 17% reduction in the odds of an apiary being Varroa infested for each kilometre increase in the squared distance from the likely site of incursion (95% Bayesian credible interval 7–28%). The pattern of spatially autocorrelated risk that remained after controlling for the effect of distance from the likely incursion site identified areas thought to be ‘secondary’ foci of Varroa infestation initiated by beekeeper-assisted movement of infested bees. Targeted investigations within these identified areas indicated that the maximum rate of local spread of Varroa was in the order of 12 km/year (interquartile range 10–15 km/year).     

Endoparasites of brushtail possums (Trichosurus vulpecula) from the South Island,New Zealand

As part of a study to assess whether endoparasites could assist in the biological control of brushtail possums in New Zealand, we investigated the composition and distribution of possum endoparasites in the South Island. Possums were collected near five of the original release areas in the South Island: Banks Peninsula, Hokitika, Nelson, Dunedin and Invercargill.

Among the nematodes, those most frequently encountered were Trichostrongylus spp., which were present in possums from all five study areas. Trichostrongylus species from possums in the Invercargill area comprised 4.5% T. colubriformis, 0.9% T. vitrinus and 11.3% T. retortaeformis. Paraustrostrongylus trichosuri and Parastrongyloides trichosuri were found only in the Invercargill area, where they infected 1.4% and 14% of possums respectively. The cestode Bertiella trichosuri was present in possums from all locations except Dunedin. The protozoan Eimeria spp. occurred in all areas.

These are the first records of Parastrongyloides trichosuri, Paraustrostrongylus trichosuri, T. vitrinus, T. retortaeformis and Eimeria spp. in South Island possums.

The prevalence of endoparasites and the intensity of infection was very low compared to the lower North Island of New Zealand. Endoparasites at the existing levels in the South Island probably have very little effect on possum populations.     

Endoparasites of brushtail possums (Trichosurus vulpecula) from the South Island, New Zealand

As part of a study to assess whether endoparasites could assist in the biological control of brushtail possums in New Zealand, we investigated the composition and distribution of possum endoparasites in the South Island. Possums were collected near five of the original release areas in the South Island : Banks Peninsula, Hokitika, Nelson, Dunedin and Invercargill. Among the nematodes, those most frequently encountered were Trichostrongylus spp., which were present in possums from all five study areas. Trichostrongylus species from possums in the Invercargill area comprised 4.5% T. colubriformis, 0.9% T. vitrinus and 11.3% T. retortaeformis. Paraustrostnmgylus trichosuri and Parastrongyloides trichosuri were found only in the Invercargill area, where they infected 1.4% and 14% of possums respectively. The cestode Bertiella trichosuri was present in possums from all locations except Dunedin. The protozoan Eimeria spp. occurred in all areas. These are the first records of Parastrongyloides trichosuri, Paraustrostrongylus trichosuri, T. vitrinus, T. retortaeformis and Eimeria spp. in South Island possums. The prevalence of endoparasites and the intensity of infection was very low compared to the lower North Island of New Zealand. Endoparasites at the existing levels in the South Island probably have very little effect on possum populations.     

Salmonella Brandenburg--emergence of a variant strain on a sheep farm in the South Island of New Zealand

Salmonella Brandenburg was initially diagnosed in New Zealand in an aborted ewe from a Merino flock in mid-Canterbury in1996. The following year, the disease occurred on farms in mid-Canterbury and on one farm near Winton in Southland (Bailey1997). Since then, this bacterium has caused widespread abortion and deaths in pregnant ewes in Southland, coastal Otago and south- and mid-Canterbury. In cattle, the same organism has caused diarrhoea and dysentery in calves and adult cattle, and abortions and deaths in first-calving cows and, to a lesser extent, in second-calving and older cows. Salmonella Brandenburg has also caused diarrhoea and fetal deaths in dogs, and diarrhoea and deaths in foals. The outbreak strain has been extensively studied using pulsed-field gel electrophoresis (PFGE). All isolates tested to date have had an indistinguishable molecular pattern with the exception of a single isolate from a sheep-yard dust sample recovered in October 2000 that is the subject of this report. The molecular pattern of the variant strain differed from that of the epidemic strain by the absence of one high molecular weight band and the addition of three lower molecular weight bands.     

Real-time PCR as a surveillance tool for the detection of Trichinella infection in muscle samples from wildlife

Trichinella nematodes are the causative agent of trichinellosis, a meat-borne zoonosis acquired by consuming undercooked, infected meat. Although most human infections are sourced from the domestic environment, the majority of Trichinella parasites circulate in the natural environment in carnivorous and scavenging wildlife. Surveillance using reliable and accurate diagnostic tools to detect Trichinella parasites in wildlife hosts is necessary to evaluate the prevalence and risk of transmission from wildlife to humans. Real-time PCR assays have previously been developed for the detection of European Trichinella species in commercial pork and wild fox muscle samples. We have expanded on the use of real-time PCR in Trichinella detection by developing an improved extraction method and SYBR green assay that detects all known Trichinella species in muscle samples from a greater variety of wildlife. We simulated low-level Trichinella infections in wild pig, fox, saltwater crocodile, wild cat and a native Australian marsupial using Trichinella pseudospiralis or Trichinella papuae ethanol-fixed larvae. Trichinella-specific primers targeted a conserved region of the small subunit of the ribosomal RNA and were tested for specificity against host and other parasite genomic DNAs. The analytical sensitivity of the assay was at least 100 fg using pure genomic T. pseudospiralis DNA serially diluted in water. The diagnostic sensitivity of the assay was evaluated by spiking 10 g of each host muscle with T. pseudospiralis or T. papuae larvae at representative infections of 1.0, 0.5 and 0.1 larvae per gram, and shown to detect larvae at the lowest infection rate. A field sample evaluation on naturally infected muscle samples of wild pigs and Tasmanian devils showed complete agreement with the EU reference artificial digestion method (k-value=1.00). Positive amplification of mouse tissue experimentally infected with T. spiralis indicated the assay could also be used on encapsulated species in situ. This real-time PCR assay offers an alternative highly specific and sensitive diagnostic method for use in Trichinella wildlife surveillance and could be adapted to wildlife hosts of any region.     

First occurrence of the reptile mite,Ophionyssus natricis (Acari: Dermanyssidae) in New Zealand

Extract

Madam:– In June 1985, a juvenile common bluetongue skink, Tiliqua scincoides, died at Wellington Zoological gardens. This animal was one of the progeny of three lizards imported from Melbourne Zoo in 1982. They joined a T. scincoides (origin unknown) already in residence at Wellington Zoo. Other juveniles had died on occasions but there were no records indicating whether the cause had been established.     

Salmonella Brandenburg - emergence of a new strain affecting stock and humans in the South Island of New Zealand

AIMS: To report information on the spread of a new strain of Salmonella Brandenburg, which affected livestock and humans in the South Island of New Zealand, and a series of small case studies designed to investigate potential transmission of infection. METHODS: Information on the occurrence and spread of S. Brandenburg in livestock was gathered from laboratory diagnostic submissions, from case studies on the faecal excretion rate in ewes, carrier status of black-backed gulls (Larus dominicanus), spread of S. Brandenburg organisms in sheep yards, infection in lambs going to meat plants, and from post-abortion pathological changes in the reproductive tract of ewes. RESULTS: A newly recognised strain of S. Brandenburg was first diagnosed in aborting sheep from a flock in mid Canterbury in the South Island in 1996. Subsequently, the disease spread to other farms in mid and south Canterbury in 1997 and to Southland and Otago in the lower half of the South Island in 1998-2003. In 1999, the same strain was responsible for abortions in cattle and gastroenteritis in calves and adult cattle. The same strain of bacterium also caused disease in horses, goats, deer, pigs and humans. Spread of the disease on farms was strongly associated with aborting ewes, which resulted in considerable environmental contamination. During the abortion season, black-backed gulls appeared to spread the disease to other farms. Other potential sources of infection were carrier sheep, contaminated water sources and contaminated sheepyard dust. Damage to the reproductive tract may affect the ability of surviving ewes to conceive. CONCLUSION: Important features of this disease are its high morbidity and mortality within a flock or herd, rapid local spread and its role as an occupational, health and safety risk to farm workers and their families.     

Evaluation of ELISA coupled with Western blot as a surveillance tool for Trichinella infection in wild boar (Sus scrofa)

Trichinella surveillance in wildlife relies on muscle digestion of large samples which are logistically difficult to store and transport in remote and tropical regions as well as labour-intensive to process. Serological methods such as enzyme-linked immunosorbent assays (ELISAs) offer rapid, cost-effective alternatives for surveillance but should be paired with additional tests because of the high false-positive rates encountered in wildlife. We investigated the utility of ELISAs coupled with Western blot (WB) in providing evidence of Trichinella exposure or infection in wild boar. Serum samples were collected from 673 wild boar from a high- and low-risk region for Trichinella introduction within mainland Australia, which is considered Trichinella-free. Sera were examined using both an ‘in-house’ and a commercially available indirect-ELISA that used excretory–secretory (E/S) antigens. Cut-off values for positive results were determined using sera from the low-risk population. All wild boar from the high-risk region (352) and 139/321 (43.3%) of the wild boar from the low-risk region were tested by artificial digestion. Testing by Western blot using E/S antigens, and a Trichinella-specific real-time PCR was also carried out on all ELISA-positive samples. The two ELISAs correctly classified all positive controls as well as one naturally infected wild boar from Gabba Island in the Torres Strait. In both the high- and low-risk populations, the ELISA results showed substantial agreement (k-value = 0.66) that increased to very good (k-value = 0.82) when WB-positive only samples were compared. The results of testing sera collected from the Australian mainland showed the Trichinella seroprevalence was 3.5% (95% C.I. 0.0–8.0) and 2.3% (95% C.I. 0.0–5.6) using the in-house and commercial ELISA coupled with WB respectively. These estimates were significantly higher (P < 0.05) than the artificial digestion estimate of 0.0% (95% C.I. 0.0–1.1). Real-time PCR testing of muscle from seropositive animals did not detect Trichinella DNA in any mainland animals, but did reveal the presence of a second larvae-positive wild boar on Gabba Island, supporting its utility as an alternative, highly sensitive method in muscle examination. The serology results suggest Australian wildlife may have been exposed to Trichinella parasites. However, because of the possibility of non-specific reactions with other parasitic infections, more work using well-defined cohorts of positive and negative samples is required. Even if the specificity of the ELISAs is proven to be low, their ability to correctly classify the small number of true positive sera in this study indicates utility in screening wild boar populations for reactive sera which can be followed up with additional testing.     

A serosurvey for antibodies to Leptospira in dogs in the lower North Island of New Zealand

AIMS: To investigate the prevalence of antibodies to endemic and exotic Leptospira serovars in samples from a serum bank, collected from dogs in the lower North Island of New Zealand. METHODS: Sera (n=466), which had been collected from apparently healthy dogs, were screened using the microscopic agglutination test (MAT) for antibodies to serovars L. borgpeterseni serovar hardjo, L. interrogans serovars pomona, copenhageni and canicola, and L. kirschneri serovar grippotyphosa. RESULTS: Antibody to Leptospiral antigen was found in 14.2% of dogs tested. The highest level of reactivity was with serovar copenhageni, to which 9.5% (41/433) of sera were positive. Antibodies to serovars grippotyphosa and canicola were not detected in this population of dogs. CONCLUSIONS: Leptospira infection is relatively common in dogs in the lower North Island . CLINICAL RELEVANCE: Vaccination of dogs against leptospirosis should be considered using vaccine containing antigen to serovars hardjo, pomona and copenhageni. The presence of moderate levels of copenhageni antibody in dogs in the lower North Island raises the possibility that this serovar has become established in rodent populations in this region.     

Knemidokoptic mange of the budgerigar (Melopsittacus undulatus) in New Zealand

Abstract

Extract

A budgerigar brought to the Wallaceville Animal Research Station for examination showed a severe chronic lesion of the beak and ceres. The lesion was heavily encrusted and showed honey-comb-like pitting (Fig. 1). Four birds of a flock of fifty were similarly affected. Mites were found in scrapings taken from the base of the beak and were identified as Knemidokoptes pilae, Lavoipierre and Griffiths, 1951 Evans, G.O. and Browning, E. 1955. Econ. Ser. Brit. Mus., 17 [Google Scholar].     

Validation of a cell culture bioassay for detection of petroleum exposure in mink (Mustela vison) as a model for detection in sea otters (Enhydra lutris)

OBJECTIVE: To validate a luciferase bioassay, which is based on a recombinant mouse hepatoma cell line, for the detection of exposure to petroleum in mustelid species. ANIMALS: 122 American mink (Mustela vison) and 15 sea otters (Enhydra lutris). PROCEDURES: Mink were exposed to Bunker C fuel oil or Alaska North Slope crude oil externally as a single exposure or internally via low dose concentrations in their ration for 6 months. Serum samples were analyzed for cytochrome P450 1A1 induction by quantification of luciferase activity in the bioassay. Mink liver specimens were also evaluated for cytochrome P450 1A1 induction by quantification of ethoxyresorufin-o-deethylase activity. Serum collected from exposed and unexposed sea otters was also analyzed using the luciferase bioassay. RESULTS: Serum samples from mink externally exposed to petroleum had significantly increased luciferase activities at 1 week after exposure. Serum samples taken at later time points or from mink exposed to either product in the ration did not cause significant luciferase induction. Samples from otters exposed to petroleum had significantly higher luciferase induction as compared with samples from otters not exposed to petroleum at 2 and 8 years after the spill. Cytochrome P450 1A1 activity in liver specimens collected from mink that were internally exposed through diet was significantly increased at the conclusion of our study. CONCLUSION AND CLINICAL RELEVANCE: The luciferase bioassay is a sensitive and specific method for determining recent exposure to petroleum in mink. The lack of luciferase activity in serum samples collected from mink greater than 1 week after experimental exposure was likely attributable to lower overall petroleum exposure in our trial, compared with natural exposures.     

Morphometric Study of the Intraorbital Muscles (Musculi bulbi) in New Zealand Rabbit

Eight female New Zealand rabbits were used. The bulbus oculi was removed bilaterally from orbita then intraorbital muscles were revealed by dissection and their length and breadth and the distance of the muscle insertion to the corneal limbus were measured. Junction formations of the insertion tendon of intraorbital muscle to the sclera were identified.     

Frequency of latent equine herpesvirus type-1 infection among a sample of horses in the central North Island of New Zealand

ABSTRACT

Aim: To estimate the frequency of infection with equine herpesvirus type-1 (EHV-1) among horses from the central North Island of New Zealand, including the frequency of detection of the D₇₅₂ genotype.

Methods: Samples of retropharyngeal lymph nodes (RLN) and submandibular lymph nodes (SLN) were dissected from the heads of 63 horses that were humanely killed for various unrelated reasons between March and November 2015. DNA extracted from these tissues was subjected to enrichment for EHV-1 sequences by hybridisation with biotin-labelled EHV-1 specific probe, followed by recovery of EHV-1 sequences on streptavidin-coated magnetic beads. Enriched samples were tested for the presence of EHV-1 using nested quantitative real-time PCR. The EHV-1 amplicons were sequenced to determine the genotype of the virus.

Results: The median age of the horses was 6 (min 2, max 30) years, and 47/63 (75%) were Thoroughbreds. EHV-1 DNA was detected in RLN samples from 6/63 (10%) horses, and three of these horses were also positive for EHV-1 DNA in SLN. The remaining horses were negative for EHV-1 DNA in both RLN and SLN samples. The N₇₅₂ genotype was detected in all positive samples and the D₇₅₂ genotype was not detected in any of the samples.

Conclusions: EHV-1 continues to circulate among horses in New Zealand. The frequency of latent EHV-1 infection among sampled horses may have been underestimated due to the sensitivity limit of the assay or because of the limited anatomical sites sampled in the study. Lack of detection of the D₇₅₂ genotype suggests that infection with this genotype is not common in horses in New Zealand.

Clinical Relevance: If live animals are tested for EHV-1 using SLN biopsy it should be kept in mind that negative results do not rule out the presence of latent EHV-1 infection at other sites inaccessible for testing. The RLN appear to be the preferred sample for detection of EHV-1 DNA in horses following recent euthanasia.     

福建鸟类新纪录——白腹军舰鸟

白腹军舰乌在福建为新纪录鸟类，属迷鸟，为国家一级重点保护野生动物。其形态特征及基本的度量数据首次予以报道。     

Hair analysis as a novel investigative tool for the detection of historical drug use/misuse in the horse: a pilot study

REASONS FOR PERFORMING STUDY: Analysis of human hair for drug residues is being used increasingly as a diagnostic tool in the investigation of drug use and abuse. Hair analysis is complementary to urine/blood testing in that it can provide an extensive historical record of drug use, is noninvasive, impersonal and can facilitate retesting. However, the technique has not been studied in horses. HYPOTHESIS: That the systemic administration of drugs in horses could be identified by the detection of drug residues in hair. OBJECTIVE: To evaluate hair analysis as a potential retrospective diagnostic test for drug administration in horses by studying the deposition of systemically administered drugs in tail hair. METHODS: Tail hairs (n = 40-50) from 4 horses with known drug histories were washed, chopped into 3-5 mm fragments and extracted overnight, in 0.1 mol/l hydrochloric acid, prior to solid-phase extraction and analysis by high-performance liquid chromatography. Horse 1, a 3-year-old Thoroughbred colt (gastric ulcer), was treated for 14 days with omeprazole; Horse 2, a 3-year-old Thoroughbred colt (anaerobic infection), was treated for 5 days with metronidazole; Horse 3, an 8-year-old Thoroughbred gelding (sinusitis), was treated for 10 days with trimethoprim/sulphadiazine; and Horse 4, a 3-year-old Thoroughbred colt (respiratory infection), was treated for 5 days with procaine benzylpenicillin. RESULTS: Omeprazole was not detected in tail hair. Metronidazole was detected in tail hair at a concentration of 0.57 ng/mg, trimethoprim and sulphadiazine at concentrations of 9.14 and 2.26 ng/mg, respectively, and procaine at a concentration of 1.66 ng/mg. CONCLUSIONS: The data presented suggest that hair analysis may become a useable technique for the retrospective detection of drug administration in horses. POTENTIAL RELEVANCE: This technique could ultimately be used as part of a prepurchase veterinary examination to identify misuse of anti-inflammatory and sedative drugs, in an in-training testing programme to identify use of anabolic agents, or to provide evidence to support post race blood or urine test results. Clearly, more extensive research will be required to evaluate the effectiveness of the technique over a much broader range of drugs.