Neuro-angiostrongylosis in wild Black and Grey-headed flying foxes (Pteropus spp)

OBJECTIVE: To identify nematodes seen in histological sections of brains of flying foxes (fruit bats) and describe the associated clinical disease and pathology. PROCEDURES: Gross and histological examination of brains from 86 free-living flying foxes with neurological disease was done as part of an ongoing surveillance program for Australian bat lyssavirus. Worms were recovered, or if seen in histological sections, extracted by maceration of half the brain and identified by microscopic examination. Histological archives were also reviewed. RESULTS: There was histological evidence of angiostrongylosis in 16 of 86 recently submitted flying foxes with neurological disease and in one archival case from 1992. In 10 flying foxes, worms were definitively identified as Angiostrongylus cantonensis fifth-stage larvae. A worm fragment and third stage larvae were identified as Angiostrongylus sp, presumably A cantonensis, in a further three cases. The clinical picture was dominated by paresis, particularly of the hindlimbs, and depression, with flying foxes surviving up to 22 days in the care of wildlife volunteers. Brains containing fifth-stage larvae showed a moderate to severe eosinophilic and granulomatous meningoencephalitis (n = 14), whereas there was virtually no inflammation of the brains of bats which died when infected with only smaller, third-stage larvae (n = 3). There was no histological evidence of pulmonary involvement. CONCLUSION: This is the first report of the recovery and identification of A cantonensis from free-living Australian wildlife. While angiostrongylosis is a common cause of paresis in flying foxes, the initial clinical course cannot be differentiated from Australian bat lyssavirus infection, and wildlife carers should be urged not to attempt to rehabilitate flying foxes with neurological disease.     

Plasma biochemistry values of recently wild-caught purple mouth moray eels (Gymnothorax vicinus)

The primary purpose of this study was to establish plasma biochemistry parameters for healthy recently wild-caught purple mouth moray eels (Gymnothorax vicinus) to provide a baseline of data for improved medical care in an aquarium or zoologic setting and for wild health assessments. Thirty-one clinically healthy purple mouth moray eels of unknown age and sex were caught from the wild, and were anesthetized 50 days following capture for blood collection from the ventral coccygeal vein. The median plasma biochemistry values were as follows: hematocrit = 21%, creatinine kinase = 2,100 U/L, lactate dehydrogenase = 97 U/L, aspartate aminotransferase = 88 U/L, alanine aminotransferase = 51 U/L, alkaline phosphatase 3,939 U/L, gamma-glutamyl transpeptidase = 1 U/L, amylase = 40 U/L, blood urea nitrogen = < 11 mg/dl, glucose = 21 mg/dl, calcium = 12.5 mg/dl, triglyceride = 206 mg/dl, creatinine = 0.1 mg/dl, cholesterol = 334 mg/dl, total bilirubin = < 0.1 mg/dl, phosphorus = 6.5 mg/dl, total protein = 4.2 g/dl, albumin = 1.5 g/dl, globulin = 2.7 g/dl, albumin/ globulin ratio = 0.6, sodium = 185 mmol/L, potassium = 3.7 mmol/L, and chloride = 175 mmol/L. Alkaline phosphatase isoenzyme results indicate that the majority of the plasma alkaline phosphatase is the liver isoenzyme. The data acquired in this study also provide baseline values for cholesterol and triglycerides in recently wild-caught moray eels to aid in monitoring elevations to these values in an aquarium setting over time so adjustments to the dietary regime may be utilized to prevent or improve conditions such as lipid keratopathy.     

Comparison of serum and plasma for determination of blood biochemical values in Malaysian flying foxes (Pteropus vampyrus).

The effects of the anticoagulant sodium heparin and time of centrifugation on 20 biochemical analytes in the blood of Malaysian flying foxes (Pteropus vampyrus) were evaluated. Paired plasma and serum samples were centrifuged at 1 hr and 6 hr postcollection. Heparinization and time of centrifugation did not significantly affect albumin, cholesterol, triglycerides, amylase, blood urea nitrogen, creatinine, alanine aminotransferase, aspartate aminotransaminase, alkaline phosphatase, calcium, sodium, and total carbon dioxide levels. Plasma was associated with higher globulin and lower potassium values. Glucose and chloride levels decreased significantly over time, whereas phosphorus levels increased. Serum creatine kinase activity at 6 hr postcollection was significantly higher than the other creatine kinase means. Sodium levels were not significantly affected by sodium heparin as used as an anticoagulant in this study.     

Plasma biochemistry reference values of wild-caught southern stingrays (Dasyatis americana).

Stingrays are prominent marine animals; however, there are few published reference values for their blood chemistry and hematology. Twenty-eight southern stingrays (Dasyatis americana) were caught using the bottom trawl nets of fishery-independent boats operated by the South Carolina Department of Natural Resources during June and July 2002 from Winyah Bay, South Carolina, to St. Augustine, Florida. Median values of blood and plasma obtained from live animals promptly after capture are as follows: packed cell volume = 0.22 L/L (22%), total solids (TS) = 56.5 g/L (5.65 g/dl), total protein (TP) = 26 g/L (2.6 g/dl), sodium = 315 mmol/L, potassium = 4.95 mmol/L, chloride = 342 mmol/L, calcium = 4.12 mmol/L (16.5 mg/dl), phosphorus = 1.5 mmol/L (4.7 mg/dl), urea nitrogen = 444 mmol/L (1,243 mg/dl), glucose = 1.69 mmol/L (30 mg/dl), aspartate aminotransferase = 14.5 U/L, creatine phosphokinase = 80.5 U/L, osmolality = 1065 mOsm/kg, and lactate = 3.1 mmol/L. Bicarbonate was less than the low end of the instrument range (5 mmol/L) in all but three samples. Anion gap was negative in all samples. Albumin was less than the low end of the instrument range (1 g/dl) in all except one sample. Osmolality was significantly higher in the rays caught in the southern region. TS and TP values were linearly related to each other, and the equation for the fitted line is TS = (11.61 x TP) + 25.4 (in g/L) [or TS = (1.161 x TP) + 2.54 (in g/dl)]. The reference ranges reported in this study can be used to aid in the management of aquarium stingrays and to create a baseline for health monitoring of the wild Dasyatis spp.     

Pathogenesis studies with Australian bat lyssavirus in grey-headed flying foxes (Pteropus poliocephalus)

OBJECTIVE: To examine the susceptibility of the grey-headed flying fox (Pteropus poliocephalus) to Australian bat lyssavirus (ABL), and to provide preliminary observations on the pathogenesis of the disease in flying foxes. PROCEDURE: Ten flying foxes were inoculated intramuscularly with ABL, and four with a bat-associated rabies virus. Inoculated animals were observed daily, and clinical samples collected every 9 to 14 days. Animals with abnormal clinical signs were euthanased, and samples collected for histological, serological, virological and immunohistological examinations. At 3 months post inoculation (PI), all survivors were euthanased, and each submitted to a similar examination. RESULTS: Three ABL-inoculated flying foxes, and two rabies-inoculated animals developed abnormal clinical signs between 15 and 24 days PI. All three ABL-inoculated animals had histological lesions consistent with a lyssavirus infection, and lyssaviral antigen was identified in the central nervous system (CNS) of each. Virus was isolated from the brain of two affected animals. Of the rabies-inoculated flying foxes, both had histological lesions and viral antigen in the CNS. Virus was recovered from the brain of only one. None of the five affected flying foxes developed anti-lyssavirus antibodies, but, by 3 months PI, five of the seven ABL-inoculated survivors, and one of the two rabies virus-inoculated survivors, had seroconverted. The dynamics of the immune responses were quite variable. CONCLUSIONS: The response of flying foxes to ABL, administered by a peripheral route of inoculation, was similar to that of bats inoculated peripherally with bat-derived rabies viruses.     

Detection of specific antibody responses to vaccination in variable flying foxes (Pteropus hypomelanus)

Megachiropteran bats are biologically important both as endangered species and reservoirs for emerging human pathogens. Reliable detection of antibodies to specific pathogens in bats is thus epidemiologically critical. Eight variable flying foxes (Pteropus hypomelanus) were immunized with 2,4-dinitrophenylated bovine serum albumin (DNP-BSA). Each bat received monthly inoculations for 2 months. Affinity-purified IgG was used for production of polyclonal and monoclonal anti-variable flying fox IgG antibodies. ELISA and western blot analysis were used to monitor immune responses and for assessment of polyclonal and monoclonal antibody species cross-reactivity. Protein G, polyclonal antibodies, and monoclonal antibodies detected specific anti-DNP antibody responses in immunized variable flying foxes, with protein G being the most sensitive, followed by monoclonal antibodies and then polyclonal antibodies. While the polyclonal antibody was found to cross-react well against IgG of all bat species tested, some non-specific background was observed. The monoclonal antibody was found to cross-react well against IgG of six other species in the genus Pteropus and to cross-react less strongly against IgG from Eidolon helvum or Phyllostomus hastatus. Protein G distinguished best between vaccinated and unvaccinated bats, and these results validate the use of protein G for detection of bat IgG. Monoclonal antibodies developed in this study recognized immunoglobulins from other members of the genus Pteropus well, and may be useful in applications where specific detection of Pteropus IgG is needed.     

Infection with Menangle virus in flying foxes (Pteropus spp.) in Australia

Objective To examine flying foxes (Pteropus spp.) for evidence of infection with Menangle virus. Design Clustered non‐random sampling for serology, virus isolation and electron microscopy (EM). Procedure Serum samples were collected from 306 Pteropus spp. in northern and eastern Australia and tested for antibodies against Menangle virus (MenV) using a virus neutralisation test (VNT). Virus isolation was attempted from tissues and faeces collected from 215 Pteropus spp. in New South Wales. Faecal samples from 68 individual Pteropus spp. and four pools of faeces were examined by transmission EM following routine negative staining and immunogold labelling. Results Neutralising antibodies (VNT titres ≥ 8) against MenV were detected in 46% of black flying foxes (P. alecto), 41% of grey‐headed flying foxes (P. poliocephalus), 25% of spectacled flying foxes (P. conspicillatus) and 1% of little red flying foxes (P. scapulatus) in Australia. Positive sera included samples collected from P. poliocephalus in a colony adjacent to a piggery that had experienced reproductive disease caused by MenV. Virus‐like particles were observed by EM in faeces from Pteropus spp. and reactivity was detected in pooled faeces and urine by immunogold EM using sera from sows that had been exposed to MenV. Attempts to isolate the virus from the faeces and tissues from Pteropus spp. were unsuccessful. Conclusion Serological evidence of infection with MenV was detected in Pteropus spp. in Australia. Although virus‐like particles were detected in faeces, no viruses were isolated from faeces, urine or tissues of Pteropus spp.     

The effect of time at which plasma separation occurs on biochemical values in small island flying foxes (Pteropus hypomelanus).

Heparinized blood samples from 15 adult small island flying foxes (Pteropus hypomelanus) were stored at 22 degrees C for 0-, 6-, and 24-hr intervals prior to centrifugation and separation of plasma from erythrocytes. Mean plasma biochemical values of 16 analytes were determined from all samples. Mean values of blood urea nitrogen, creatinine, total protein, albumin, globulin, alkaline phosphatase, alanine transaminase, aspartate transaminase, cholesterol, calcium, sodium, and bilirubin did not change significantly over 24 hr at 22 degrees C. Glucose was decreased at 6 and 24 hr. Potassium and phosphorus increased and chloride decreased, respectively, between 6 and 24 hr.     

Microvasculature of the medulla oblongata in the Lyle's flying fox (Pteropus lylei)

The microvasculature of the medulla oblongata in 15 adult Lyle's flying foxes (Pteropus lylei) was elucidated by using the vascular corrosion cast technique combined with scanning electron microscopy. The study showed that the medulla received the main arterial supply from branches of the vertebrobasilar system. The supplied areas were divided into three groups: ventral, lateral and dorsal groups. All vessel groups gave off circumferential and perforating branches; moreover, these branches anastomosed with one another in two fashions: end-to-end and side-by-side arrangements. In addition, the ramifications of the branches were L and Y types. The L type was more frequently found than the Y one. The density of capillaries in the nuclei was greater than that in the area of nerve fibres. Numerous arterial sphincters and smooth muscle cells were observed. Furthermore, capillaries in the medulla were of the continuous type, whereas those in the area postrema were fenestrated. The venous drainage system of the medulla was classified into caudal, middle and rostral parts. All of them emptied into both the sigmoid sinus and internal jugular vein. It was concluded that these vascular patterns provide sufficient blood supply to the medulla oblongata of P. lylei when abrupt changes in the position of this bat occurs.     

Chemical characterization of milk oligosaccharides of the island flying fox (Pteropus hypomelanus) (Chiroptera: Pteropodidae)

Although a considerable amount of information has accumulated about oligosaccharides in the milk and colostrum of representatives of various mammalian orders, nothing is so far known concerning these sugars in the milk of any bat species (order Chiroptera). In this study, we determined that the following oligosaccharides occur in milk of the island flying fox, Pteropus hypomelanus (Chiroptera: Pteropidae): Gal(α1–3)Gal(β1–4)Glc (isoglobotriose), Gal(β1–4)GlcNAc(β1–3)Gal(β1–4)Glc (lacto‐N‐neotetraose), Gal(β1–4)GlcNAc(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (lacto‐N‐neohexaose) and Neu5Gc(α2–3)Gal(β1–4)Glc (3′‐NGc‐SL). However, lactose was found to be the dominant saccharide in this milk, as in most eutherian mammals. The biologic importance of oligosaccharides in Chiropteran milks warrants further study.     

Reference ranges for hematologic and serum biochemical values in llamas (Lama glama)

Hematologic and serum biochemical values were determined in 174 llamas of all age groups and both sexes from ranches in California and Nevada. Compared with hematologic values for horses and cattle, llama erythrocytes were more numerous (10.1 to 17.3 x 10(6)/microliters), but the PCV was lower (25 to 45%) because the smaller elliptical cells pack tighter. The mean corpuscular volume was half that of horses and cattle (22 to 29.5 fl). The mean corpuscular hemoglobin concentration was higher (38.9 to 46.2 g/dl), and the mean corpuscular hemoglobin slightly lower (9.6 to 12.6 pg). Most serum biochemical values were similar to those of cattle and horses, with the exception of triiodothyronine (48 to 468 ng/dl) and thyroxin (9.8 to 30 micrograms/dl), which are up to 10 times higher than values for other domestic species.     

Evaluation of injury severity and hematologic and plasma biochemistry values for recently captured North American river otters (Lontra canadensis).

As part of a reintroduction program, blood samples from free-ranging, recently captured Nearctic river otters (Lontra canadensis) in eastern New York state were collected and analyzed to determine baseline hematology and plasma biochemistry values for the source population, and to determine whether these values were significant predictors of trap-injury status. Based on physical exam, each otter was classified as uninjured, moderately injured, or severely injured. Clinical pathology parameters were compared across sex, age class, and injury classification. The increase in likelihood of a change in each parameter in injured versus uninjured otters was determined using logistic regression. Baseline hematology and plasma biochemistry values did not differ significantly from published values for captive otters in zoos or other reintroduction programs. Plasma aspartate aminotransferase levels increased as time from capture to venipuncture decreased. Some otters in this study showed clinical signs consistent with exertional myopathy, possibly altering our calculation of baseline values. Our results suggest that the hematology and plasma biochemistry values obtained in this recently captured population of otters are generally not good predictors of capture-related injury. This could be due to disease processes that are not readily visible upon physical examination or because changes in these values may be associated with factors independent of capture-related injury.     

Hematology and biochemistry reference values for Ontario swine.

The purpose of this study was to establish blood reference values for Ontario swine from various age groups. Weanling pigs, feeder pigs, gilts and sows on 11 randomly selected swine farms were sampled using the orbital sinus bleeding technique. Routine hematological and biochemical determinations were performed using whole blood and serum. For the variables examined in each age group the means, the standard deviations and the 95% upper and lower limits were calculated.     

Hemolymph biochemistry reference ranges for wild-caught Goliath birdeater spiders (Theraphosa blondi) and Chilean rose spiders (Grammostola rosea).

Theraphosid spiders have become increasingly popular for private and public uses in the United States. However, little is known about their physiology from a medical standpoint. This study represents the first attempt to establish reference hemolymph values for two common species of theraphosids, the goliath birdeater spider (Theraphosa blondi) and the Chilean rose spider (Grammostola rosea). Eleven T. blondi and twelve G. rosea, all wild-caught subadults, were obtained after importation and hemolymph was collected for biochemical analysis. After 8 wk of captivity, hemolymph was again collected from the spiders and analyzed. The biochemical analytes measured in the study included aspartate transferase, creatine kinase, glucose, total protein, albumin, uric acid, blood urea nitrogen, phosphorous, calcium, potassium, and sodium. The osmolality of the hemolymph was estimated for each spider using two different formulae. There were significant differences in body weight, sodium, potassium, and osmolality between the sampling times for both species. There were also significant differences in creatine kinase, calcium, total protein, and blood urea nitrogen between sampling periods for T. blondi. The results of this study suggest that serial hemolymph samples may be used to assess the hydration status of theraphosid spiders. In addition, the differences in hemolymph analytes between spiders suggest that there may be differences between species that should be addressed in future studies.     

Canine hematology and biochemistry reference values.

Reference hematology and biochemistry values for 53 variables are presented from 51 clinically healthy dogs, 26 female and 25 male, approximately six to 24 months of age and of mixed breed. These dogs were sampled because of their good health status and the opportunity to collect the volume of blood required to complete the variable analysis of interest. Collection of blood specimens and laboratory analysis was done in a standard described manner, the latter including a continuing quality control program. For each variable the data were examined for homogeneity and when present, outliers (n = 9) were excluded. Parametric analysis was used to calculate the reference interval for those variables which had a Gaussian distribution or could be changed to a Gaussian distribution by any of four transformations. For those variables in which Gaussian distribution was not present or attained, nonparametric analysis was used. Due to the small size of the population sample, the uncertainty of breed and the exact age of each dog, breed, age and sex effects were not examined. Reference values should be used to assist interpretation of observations obtained from an animal or animals of comparable origin, i.e. similar subpopulation, and only if the same laboratory techniques are followed. Until each laboratory is able to generate reference values using adequate sample size and current methodology for the numerous subpopulations of interest, reference intervals such as these are useful to clinicians and researchers.     

Hematology and biochemistry reference values for the ranch fox.

Reference hematology and biochemistry values are presented from a mixed population of 30 silver and red foxes of both sexes, reared and living under fox-farming conditions in southern Ontario. Based on history and physical examination, the animals in this study were clinically healthy at the time of blood collection and maintained under similar husbandry practices. The observations were examined for outliers and Gaussian distribution before and after one of three transformations. Parametric analysis was used to determine lower and upper reference limits. Where observations were not Gaussian, minimum and maximum values are given. These reference values are presented as a usable first approximation of population reference values to assist clinicians and researchers in their interpretation of observations obtained from foxes of similar populations.