Texas Veterinary Medical Diagnostic Laboratory Research Articles

85 Evaluation of an Oral Supplemental Cannabidiol Product for Acceptability in Mature Horses

Abstract Thirty stock type geldings (15 ± 3 y; 556 ± 63 kg BW) were used in a randomized complete design for a 28-d trial to evaluate the influence of cannabidiol (CBD) oil supplementation on health of mature horses by conducting a blood chemistry panel and evaluating the presence of banned substances. Horses were stratified by BW and age, and randomly assigned to 1 of 3 dietary treatments formulated with canola oil to provide.50 mg CBD/kg BW (TRT1; n = 10), 0.75 mg CBD/kg BW (TRT2; n = 10), or 0.00 mg CBD/kg BW (canola oil; CON; n = 10) only as determined by manufacturer (Arrowhead Labs). Treatments were individually fed and top-dressed onto a commercially available concentrate twice daily at 12 h intervals using attachable feed bags. Diets were formulated to meet or slightly exceed nutritional requirements for mature horses at maintenance. Between meals, horses were maintained in adjacent dry lots and received coastal bermudagrass hay ad libitum. Body weight was obtained, and body condition scores (BCS) were assigned every4 d. On d 0 and 28, blood was collected via jugular venipuncture and serum was harvested to perform a blood chemistry panel and drugs of abuse screening at the Texas Veterinary Medical Diagnostic Laboratory (TVMDL; College Station, TX). Data were analyzed using PROC MIXED of SAS (v9.4), and the model included treatment, time, and the treatment × time interaction for BW and BCS. Blood chemistry variables on d 0 were used as a covariate and the main effect tested was treatment. Linear and quadratic orthogonal polynomial contrasts were used to partition sum of squares. Analysis of supplement samples revealed supplemented products contained lower CBD concentrations then indicated from initial testing. Therefore, horses in TRT1 and TRT2 received an average of 0.13 mg CBD/kg and 0.12 mg CBD/kg BW, respectively. Dietary treatments did not affect concentrate intake, BW, or BCS. Supplementation of CBD did not result in the presence of any banned substances in serum, including CBD, 7-carboxycannabidiol, 7-Nor-7-carboxycannabidiol, and tetrahydrocannabinol (THC). Following 28 d of supplementation, gamma-glutamyl transferase (GGT) responded quadratically (P = 0.06) to treatment, with a peak in GGT in horses receiving TRT2. Serum creatinine concentration tended (P = 0.06) to decrease with increasing inclusion of CBD in the diet. In contrast, the main effect of treatment on Ca concentrations was linear (P = 0.01) and characterized by decreased Ca values for TRT1 compared with TRT2 and CON. Canola based CBD oil was well-accepted by mature horses, banned substances were not detectible in blood, and blood chemistry parameters were not adversely affected as a result of supplementation; however, more information is needed to improve stability of CBD used in dietary products.

Evaluation of an Oral Supplemental Cannabidiol Product for Acceptability and Performance in Mature Horses.

Thirty stock type geldings (15 ± 3 years; 556 ± 63 kg BW) were used in a randomized complete design over 28 days to determine the influence of cannabidiol (CBD) oil supplementation levels on body weight, body condition, and blood chemistry. Horses were randomly assigned to one of three dietary treatments (n = 10 per treatment) formulated with canola oil to provide 1.50 mg CBD/kg BW (TRTA), 0.75 mg CBD/kg BW (TRTB), or 0.00 mg CBD/kg BW (canola oil; CTRL). Treatments were top-dressed onto concentrate and individually administered twice daily. Horses were maintained in adjacent dry lots and received coastal bermudagrass hay ad libitum. Body weight and body condition scores (BCS) were obtained every 14 days. On day 0 and 28, blood was collected via jugular venipuncture and serum was harvested to perform a blood chemistry panel and drugs of abuse screening at the Texas Veterinary Medical Diagnostic Laboratory. Data were analyzed using PROC MIXED of SAS (v9.4), and the model included treatment, time, and the treatment × time interaction, and linear and quadratic orthogonal polynomial contrasts to partition sum of squares. Analysis of composited treatment samples revealed lower CBD concentrations than indicated from initial testing by the manufacturer (0.13 mg CBD/kg in TRTA; 0.12 mg CBD/kg in TRTB). At this level of supplementation, canola-based CBD oil was well-accepted by mature horses, banned substances were not detectable in blood, and blood chemistry parameters were not adversely affected as a result of supplementation. More research is warranted to describe the discrepancy between formulated levels compared to tested levels of CBD in the canola-based supplement.

Distribution and characterization of Heterobilharzia americana in dogs in Texas

Heterobilharzia americana is a trematode parasite (family Schistosomatidae) that infects a wide range of wild mammalian hosts. Canine cases have been reported in the Gulf coast and south Atlantic states, Kansas, and Oklahoma. A total of 238 canine H. americana cases in Texas were retrospectively collected for a period of approximately 22 years from case records at the Texas Veterinary Medical Diagnostic Laboratory and the Veterinary Medical Teaching Hospital pathology service, diagnostic parasitology service, and Gastrointestinal Laboratory at Texas A&M University College of Veterinary Medicine. Of these cases, 26 patients had 1–2 repeat positive tests for a total of 268 positive tests (26 biopsies, 39 necropsies, 160 fecal examinations, and 43 PCR). Multiple dogs were infected in 12 households. Cases were distributed primarily in the eastern region of Texas in 42 of 254 counties. Cases were seen as far west as Kerr county and in counties bordering Oklahoma, Louisiana, Mexico, and the Gulf of Mexico. The median dog age was 5.6 years (2.7 months to 17.2 years) and the median weight was 20.5kg (1–61.6kg). All American Kennel Club (AKC) breed groups were represented (n=186): crossbred (20%), herding (17.8%), sporting (16.1%), toy (10.8%), hounds (10.8%), working (10.1%), terrier (8.5%), non-sporting (4.9%), and miscellaneous (1%). No seasonal pattern of diagnosis was apparent. Clinical signs reported (n=90) were diarrhea (67%), weight loss (38%), anorexia/hyporexia (27%), vomiting (22%), hematochezia (20%), lethargy (17%), polyuria/polydipsia (6%), and collapse (3%). In 39 necropsy cases, trematode eggs were identified by histopathology in the small intestine (84%), liver (84%), large intestine (39%), pancreas (35%), lung (9%), lymph node (8%), spleen (4%), and stomach (3%). Adult parasites were identified histologically in four cases. Granulomatous inflammation associated with the eggs was the most commonly reported histopathologic change. Other changes reported were fibrosis, pigment in macrophages, and organ mineralization. Glomerulonephritis was identified in four cases. Of 20 necropsy cases where death was attributable to H. americana infection, only one case was diagnosed ante mortem. Eleven of these dogs were examined by a veterinarian but H. americana was included as a differential diagnosis in only two cases. Reported differential diagnoses included ethylene glycol toxicity, cholecalciferol toxicity, lymphoma, and pancreatitis. These data indicate that this parasite is more widely distributed and more common than is generally recognized. Increased awareness may aid in more diagnoses and timely therapy.

Development and performance evaluation of calf diarrhea pathogen nucleic acid purification and detection workflow

Calf diarrhea (scours) is a primary cause of illness and death in young calves. Significant economic losses associated with this disease include morbidity, mortality, and direct cost of treatment. Multiple pathogens are responsible for infectious diarrhea, including, but not limited to, Bovine coronavirus (BCV), bovine Rotavirus A (BRV), and Cryptosporidium spp. Identification and isolation of carrier calves are essential for disease management. Texas Veterinary Medical Diagnostic Laboratory current methods for calf diarrhea pathogen identification include electron microscopy (EM) for BCV and BRV and a direct fluorescent antibody test (DFAT) for organism detection of Cryptosporidium spp. A workflow was developed consisting of an optimized fecal nucleic acid purification and multiplex reverse transcription quantitative polymerase chain reaction (RT-qPCR) for single tube concurrent detection of BCV, BRV, and Cryptosporidium spp., and an internal control to monitor nucleic acid purification efficacy and PCR reagent functionality. In "spike-in" experiments using serial dilutions of each pathogen, the analytical sensitivity was determined to be <10 TCID(50)/ml for BCV and BRV, and <20 oocysts for Cryptosporidium spp. Analytical specificity was confirmed using Canine and Feline coronavirus, Giardia spp., and noninfected bovine purified nucleic acid. Diagnostic sensitivity was ≥98% for all pathogens when compared with respective traditional methods. The results demonstrate that the newly developed assay can purify and subsequently detect BCV, BRV, and Cryptosporidium spp. concurrently in a single PCR, enabling simplified and streamlined calf diarrhea pathogen identification.

Evaluation of effects of high incubation temperatures on results of protozoal culture and real-time PCR testing for Tritrichomonas foetus inoculated in a commercially available self-contained culture media system

To evaluate effects of high incubation temperatures on results of protozoal culture and real-time PCR testing for Tritrichomonas foetus inoculated in a commercially available self-contained culture media system. In vitro experimental study. 2 strains of T foetus (1 field isolate from the University of California-Davis and 1 field isolate from the Texas Veterinary Medical Diagnostic Laboratory). 2 sets of 36 dual-chamber media pouches were inoculated with T foetus (36 sample pouches/strain) and incubated at temperatures of 37.0°C (98.6°F), 46.1°C (115.0°F), or 54.4°C (130.0°F) for 1, 3, 6, or 24 hours. Six uninoculated media samples in pouches stored at 37.0°C for the entire treatment period were used as negative controls. Pouches were removed from incubators and stored at 22.2°C (72.0°F) until all treatments were complete. Samples were submitted to a diagnostic laboratory for protozoal culture and real-time PCR testing. T foetus was detectable microscopically in inoculated pouches incubated at 37.0°C regardless of exposure time, whereas those incubated at 46.1°C yielded T foetus after 1 and 3 hours only, and those incubated at 54.4°C yielded T foetus after 1 hour only. Testing via real-time PCR assay yielded positive results for all inoculated media samples and negative results for all uninoculated control samples. Samples collected into the self-contained culture media system for T foetus testing via culture alone should be protected from high temperatures. Realtime PCR amplification may be a more reliable method for identification of the organism if storage and transport temperatures cannot be controlled.

Spatio-temporal epidemiology of Tritrichomonas foetus infection in Texas bulls based on state-wide diagnostic laboratory data

Texas is the largest cattle producing state and suffers severe economic losses due to abortions caused by the protozoan parasite Tritrichomonas foetus. The objective of this study was to use data from the state-wide diagnostic laboratory system of Texas to investigate the occurrence and spatio-temporal distribution of bovine trichomoniasis (BT) in Texas, and to identify spatial disease clusters within the state. The study population consisted of bulls tested for BT in 2010 by the Texas Veterinary Medical Diagnostic Laboratory system that performs at least 95% of all T. foetus testing in the state. Preputial samples were cultured and diagnosis was made by real-time polymerase chain reaction (PCR). Data on BT was aggregated at the county level with time aggregation of one month. The scan statistics was used to identify spatial disease clusters. The database included 31,202 test results with a proportion of positives of 3.7%. As expected, BT was present throughout Texas. Testing prevalence was highest in the summer (5.5%). The scan statistics identified a spatial cluster in southeastern Texas, which could only partially be explained by cattle herd density. The findings of this study provide baseline data to monitor the success of BT control activities in Texas and aids in generating hypotheses regarding specific risk factors for the disease. The identification of high-risk areas and periods is also essential to improve intervention efforts.

Change in Predominance ofBovine Viral Diarrhea VirusSubgenotypes among Samples Submitted to a Diagnostic Laboratory over a 20-Year Time Span

Although the causative agent of bovine viral diarrhea was initially categorized as 1 species, phylogenetic analysis revealed that these viruses belong to 2 different species, Bovine viral diarrhea virus 1 (BVDV-1) and BVDV-2, with 2-11 subgenotypes within each species. Distribution of species and subgenotypes has been shown to vary with geographic region. Whether distribution shifts over time is not known. Surveys conducted between 1994 and 2008 reported 3 subgenotypes circulating among cattle in the United States: BVDV-1a, BVDV-1b, and BVDV-2a. The average percent prevalence of BVDV-1a, BVDV-1b, and BVDV-2a strains reported in surveys before 2001 were 21%, 43%, and 36%, respectively. Surveys conducted on viruses isolated after 2001 reported decreasing percentages of BVDV-1a and BVDV-2a strains, with BVDV-1b strains accounting for 75-100% of samples. Comparison of these surveys is confounded by differences in geographic location, collection methods, and sample type used in the survey. The purpose of the present study was to determine whether the prevalence of BVDV subgenotypes shifted in samples collected from the same geographic region and by the same laboratory over time. BVDV strains isolated in years 1988, 1998, and 2008, at the Texas Veterinary Medical Diagnostic Laboratory, Amarillo, Texas, were genotyped, and the prevalence of BVDV-1a, BVDV-1b, and BVDV-2a strains were determined. Typing, on the basis of phylogenetic analysis, was done on 148 samples. The strongest trend detected among these samples was a pronounced decrease in the number of BVDV-1a strains over time.

Eight Cases of Feline Cutaneous Leishmaniasis in Texas

Leishmaniasis is a zoonotic disease caused by intracellular Leishmania protozoa that are transmitted by sandflies. The disease occurs in 3 forms: cutaneous, mucocutaneous, and visceral. Cutaneous leishmaniasis has been reported in cats in Europe and South America and in 1 cat from Texas. Leishmania mexicana is endemic in Texas and has been reported to cause cutaneous lesions in humans. This article describes the pathology of 8 biopsy cases of feline cutaneous leishmaniasis presented to the Texas Veterinary Medical Diagnostic Laboratory over a 3.5-year period. The median age of the cats was 3 years; each was presented with nodular, ulcerative lesions on the pinnae and less commonly on the muzzle and periorbital skin. Histologically, the lesions were nodular to diffuse histiocytic dermatitis with numerous amastigotes (2-4 μm) within macrophages and occasionally within the interstitium. Organisms were often contained within round, clear, intracellular vacuoles. In areas of necrosis, organisms were also free within the interstitium. The overlying epidermis was hyperkeratotic, hyperplastic, and often ulcerated. The organisms were not argyrophilic (Gomori methenamine silver), reacted poorly with periodic acid-Schiff reagent, and were inconsistently basophilic with Giemsa. Although not readily visible histologically, kinetoplasts were evident in amastigotes in cytologic preparations. The lesions were similar to those described for cutaneous L. mexicana infection in humans. In 5 of the 8 cats, Leishmania mexicana DNA was amplified from paraffin-embedded tissue by polymerase chain reaction and sequenced.

Case reports of melamine-induced pathology in penaeid shrimp fed adulterated feeds

Shrimp (Penaeus monodon and P. vannamei) specimens were submitted to the University of Arizona's Aquaculture Pathology Laboratory (UAZAPL) and to the Texas Veterinary Medical Diagnostic Laboratory (TVMDL) in 2007 and 2008 from shrimp-rearing facilities in India and Indonesia for histological testing. These were found to present prominent golden to greenish-brown needle- and plate-like birefringent crystals within multifocal hemocytic granulomas in the antennal gland tubules and peritubular hemal sinuses. Their appearance was very similar to melamine-cyanuric acid-induced crystals previously described from cat and dog kidneys with melamine-associated renal failure (MARF). Significant chronic mortalities were reported from the affected P. vannamei farms in Indonesia, but were not observed in the affected P. monodon facility in India. Shrimp feed was suspected as the source of melamine due to the similarity of the shrimp antennal gland lesions to those present in MARF. 'Normal' and 'suspect' feed samples from the facilities in Indonesia and India were sent to regional laboratories for analysis. Melamine was detected in 2 of 4 feed samples from an affected Indonesian farm. Melamine was not detected in 'normal' feed from the Indian facility, but it was found in 2 'suspect' samples (Feeds A and B) at levels of 183.39 and 112.50 ppm, respectively. A bioassay of Feed A with P. vannamei at UAZAPL confirmed that the melamine-contaminated feed induced prominent granulomas in the antennal gland with the characteristic crystals within 10 d of the first feeding, experimentally confirming the direct relationship of melamine-adulterated feed to the unique pathology observed.

196 COMPARING OOCYTE LIPID CONTENT WITH CIRCULATING CHOLESTEROL AND TRIGLYCERIDE LEVELS OF BOS TAURUS AND BOS INDICUS DONOR COWS

Intracellular lipid content has been found to be higher in Bos indicus oocytes compared with Bos taurus oocytes (Ballard et al. 2007 Reprod. Fertil. Dev. 19, 170). The objective of this study was to further determine whether there was a correlation between oocyte lipid content and circulating cholesterol (CHL) and triglyceride (TRG) levels of mature purebred Brahman (BR; n = 11) and English breed (EN; n = 13) beef cows. All donor cows were maintained on the same ration 30 days prior to and during the oocyte collection interval. Oocytes were collected from donors at 30-day intervals (3 replicates/female) by transvaginal ultrasound-guided aspirations. Blood samples were collected to evaluate total circulating CHL and TRG levels just prior to CIDR insertion and again prior to oocyte collection. Follicle-stimulating hormone (Folltropin-V; Bioniche, Belleville, Ontario, Canada) was given twice daily for 3 days in decreasing doses beginning on Day 4 after CIDR insertion, with oocyte recovery on Day 8. The mean number of follicles aspirated/donor and oocytes recovered/donor were 12 and 11 for the BR and 18 and 7 for the EN donors, respectively. Oocytes were matured in TCM-199 with 10% fetal bovine serum + bovine LH and bovine FSH (0.01 U mL–1). After 20 h, mature oocytes with a visible polar body (BR = 242/391 or 61%, and EN = 170/258 or 65%) were denuded by vortexing in Tyrodes HEPES medium + BSA (0.03 mg mL–1). Visual color scores (1 = light, 2 = medium, 3 = dark) were then assigned to the oocytes. Buoyancy of mature oocytes was then measured by using a sucrose step-density gradient column prepared with sucrose and Dulbecco's PBS. Results from the sucrose gradients ranged from 23% (high lipids) to 35% (lower lipids). The oocytes were stained with Nile Red and evaluated by fluorescent microscopy. Oocyte images were evaluated by using Scion Image software to calculate the Nile Red units (NRU; higher NRU = higher lipid content). Serum was analyzed (Texas Veterinary Medical Diagnostic Laboratory) for CHL and TRG concentrations. Data were analyzed by one-way ANOVA. There was no difference between visual color scores for oocytes from BR and EN donors. However, BR oocytes had significantly (P &lt; 0.05) lower buoyant density and significantly higher mean NRU scores (32% and 173) compared with oocytes harvested from EN donors (33% and 152), respectively. Serum CHL and TRG levels were both significantly higher (P &lt; 0.05) in the BR donors (150 and 33.2) compared with the EN donors (110 and 25.5), respectively. These results suggest that serum cholesterol and triglyceride levels may be predictive of donor oocyte lipid content.

Cantharidin poisoning of emu chicks by ingestion of Pyrota insulata.

In April and May 1992, the Texas Veterinary Medical Diagnostic Laboratory (TVMDL) received for necropsy several frozen 1–3-month-old emu chicks from 1 ranching operation. Insects had swarmed to blooms on mesquite trees (Prosopis glandulosa) near the chick barn, and when a cool front arrived, lights were left on inside to encourage the chicks to seek shelter. As dusk fell, the insects were attracted to the lighted area, and they could be seen covering the floor of the barn and other surfaces accessible to the chicks. The history accompanying the birds described the chicks’ avid consumption of the insects. Some chicks remained clinically normal while others became ataxic, vomited beetles, became prostrate, and died. Some survived by vigorous treatment with oral fluids. Submissions to TVMDL consisted of proventricular contents, the frozen carcasses of 4 emu chicks, and a sample of the suspect insects. At necropsy, the esophagus of each bird was congested and edematous, and the proventricular serosa was hemorrhagic. The gizzard linings were sloughed, the intestinal contents were pink and the livers were pale. Tissue samples for histopathologic evaluation were fixed in 10% neutral buffered formalin, processed, embedded, sectioned and stained with hematoxylin and eosin (HE) prior to microscopic examination. Ingesta were examined under a dissecting microscope. Only 1 of the birds had a large volume of intact ingesta, which included fibrous plant material, small pebbles and 1 beetle about 1 cm long. Insect fragments were found in the proventricular and gizzard contents of 2 of the other chicks. Microscopically, the lesions varied in severity within each animal (Fig. 1). In some chicks, areas of the esophageal mucosa were overlaid with a thick coat of mucus (Fig. 1b). In others, there was multifocal epithelial ulceration with diffuse submucosal necrosis and thrombosis of small submucosal blood vessels (Fig. 1c–e). Catarrhal esophagitis and multifocal esophageal ulceration with underlying inflammation and necrosis were suggestive of exposure to a chemical irritant in a solid form, which was consistent with ingestion of a blister beetle, as opposed to a liquid irritant, which would have produced a more uniform lesion. Ingesta and insects were extracted and analyzed for can-

Comparison of the Gimenez Staining Method and Antigen Detection ELISA with Culture for Detecting Chlamydiae in Birds

Chlamydiosis, caused by Chlamydia psittaci, an obligate intracellular bacterium, is a serious health concern for various types of birds and their owners. Disease can occur as a chronic inapparent, subacute, acute, or peracute infection. Culture for chlamydiae is considered the “gold standard” for evaluating other methods, even though it probably does not have 100% sensitivity nor 100% specificity in live human subjects, and culture of multiple sample types from birds may increase the sensitivity. Multiple cultures may increase chances of recovering chlamydiae from live birds, but it probably is not advisable to delay treatment of birds critically ill with signs consistent with chlamydiosis. Monoclonal antibodies that detect chlamydial lipopolysaccharide have allowed development of an enzyme-linked immunosorbent assay (ELISA) for rapid detection. Two commercially available kits have been evaluated for use in birds. Microscopic examination of impressions of uncut surfaces of bird organ tissues and inoculated cell culture monolayers using the Gimenez staining method (GSM) also was reported as a rapid diagnostic procedure for examining dead birds. The purpose of this study was 2-fold: 1) to expand the comparison of 1 commercially available ELISAB with chlamydial isolation attempts from live birds and 2) to compare results of antigen-detection ELISA and the GSM with culture results on dead birds. Samples used in this study were submitted to the Texas Veterinary Medical Diagnostic Laboratory (TVMDL) for chlamydial testing. Cloacal swabs, choanal slit swabs, and fecal samples from live birds were submitted in chlamydial transport medium. Some fresh fecal samples also were submitted. Fresh fecal material was placed into chlamydial transport medium to make an approximate 20% (w:v) suspension, which was centrifuged at 1,000 x g for 15 minutes and then diluted 1:2 for isolation attempts. For the ELISA testing, 1.0 ml of fecal suspension was centrifuged at 3,000 x g for 20 minutes, and the supematant fluid was discarded. A swab was then used to collect the pellet. Visceral and other organs from dead birds necropsied by referring veterinarians or TVMDL personnel were processed for the GSM, ELISA, and isolation procedures. Impressions were most often made of liver and spleen uncut surfaces and occasionally of the pericardium, air sacs, or lungs. These impressions were stained by the GSM and examined microscopically. 4,5 Suspensions (20%, w:v) of pooled organ tissues for cell monolayer inoculation were made in cell culture growth medium and centrifuged for 15 minutes at 1,000 x g. For ELISA of tissues, swabs were inserted into spleen and liver and then air dried.

Salmonella typhimurium agglutinins in exotic bird sera in the USA.

A preliminary survey of 2,407 psittacine bird sera for Salmonella typhimurium agglutinins has been reported.’ The purpose of the current survey was to obtain additional data on psittacine bird sera and to expand testing to include other types of exotic birds. The 3,915 psittacine bird sera and the 239 pigeon and dove sera tested were selected from those submitted to the Texas Veterinary Medical Diagnostic Laboratory (TVMDL) for Chlamydia testing as previously described. The 17 ostrich sera were submitted specifically for Salmonella serology because of an existing disease problem. The 7 emu sera were submitted for Salmonella serology for a health status check. The whole bacterial cell-stained antigen and the slide agglutination testing methods were used as previously described. Antigen was purchased from the University of Minnesota and stained at the TVMDL. The results on all types of birds are shown in Table 1. Positive reactions (complete agglutination) occurred in sera from 16 (3.3%) of 489 African gray parrots submitted singly and 23 (28.75%) of 80 submitted from a breeder group; 8 (0.7%) of 1,222 Amazon parrots; 1 (0.7%) of 141 cockatiels; 2 (0.4%) of 566 cockatoos; 1 (0.4%) of 227 conures; 1 (0.2%) of 636 macaws; 1 (3.0%) of 33 Senegal parrots; 1 (unspecified parrot type) (0.2%) of 521 mixed types of psittacine birds; 6 (2.5%) of 239 pigeons and doves; and 1 (5.8%) of 17 ostriches. Geographic locations of serologically positive birds, which were from 12 states widespread across the USA, are not shown. Equivocal reactions (partial agglutination) were found in sera from 3 African gray parrots, 8 Amazon parrots, 3 macaws, 1 Pionus parrot, 2 parrots of unspecified type, 2 pigeons and doves, and 1 ostrich. All of the 7 emu sera were negative. The overall percentage of positive reactions in psittacine bird sera was comparable to that reported previously. Again, a group of Congo African gray parrots had a high percentage of reactors. This group was established in a breeder facility, whereas the first such group reported was a newly imported group. The Congo African gray parrot appears to be highly susceptible to S. typhimurium infection. The positive serologic results indicate that Amazon parrots and pigeons/doves also probably are important hosts of S. typhimurium. Because of the small numbers of cockatiel and Senegal parrot sera tested, it is not clear how important these psittacine bird types are as hosts of S. typhimurium, although the percentages of positive results were respectively comparable to those of Amazon parrots and African gray parrots. Salmonellosis caused by S. typhimurium can be a problem

Clinical and epizootiologic characteristics of dogs seropositive for Borrelia burgdorferi in Texas: 110 cases (1988)

Summary Of 2,409 canine serum samples submitted to the Texas Veterinary Medical Diagnostic Laboratory between Jan 1, 1988 and Dec 31, 1988 and tested by immunofluorescent antibody technique for antibody to Borrelia borgdorferi, 132 (5.5%) had positive results. Clinical and epizootiologic characteristics of seropositive dogs from Texas (n = 110) were examined. Male dogs were more likely than female dogs to be seropositive for B burgdorferi. The most frequent clinical sign of disease described in seropositive dogs was lameness; neurologic, ophthalmologic, dermatologic, renal, and hepatic signs also were reported by referring veterinarians.

Epizootiologic association between feline immunodeficiency virus infection and feline leukemia virus seropositivity

Summary Five hundred twenty-one feline serum samples submitted to the Texas Veterinary Medical Diagnostic Laboratory between Nov 1, 1988, and Jan 31, 1989 were tested for antibody to feline immunodeficiency virus (fiv) by use of an elisa. The prevalence of fiv infection in this population was 11.3% (95% confidence interval: 8.6 to 14.0%). Serologic test results for FeLV were available for 156 of the 521 cats. A significant (P = 0.008) association between fiv infection and FeLV seropositivity was observed; FeLV-positive cats were nearly 4 times more likely to be seropositive for fiv than were FeLV-negative cats. The association remained statistically significant (P = 0.021) after adjusting for age and gender, using multiple-logistic regression analysis.

Case Studies on Second-Generation Anticoagulant Rodenticide Toxicities in Nontarget Species

Specimens from 10 cases of second-generation anticoagulant rodenticide poisoning in dogs and cats were submitted to the Texas Veterinary Medical Diagnostic Laboratory during 1986 and 1987. The clinical signs most frequently observed were lethargy, dyspnea, and ventral hematomas; common necropsy findings included hemoperitoneum, hemothorax, and pulmonary hemorrhage. In the instances when histopathological examination of the tissue was done, it supported a diagnosis of coagulopathy. The presence of anticoagulants in serum or liver was confirmed by high pressure liquid chromatography, gas chromatography/mass spectrometry, or a combination of the two. Five cases of brodifacoum poisoning, 2 of bromadiolone, and 3 of diphacinone toxicity were verified. Concentrations of these rodenticides ranged from approximately 0.001 to 12 ppm.

Viral intestinal infections of animals and man

The extensive use of negative staining techniques and electron microscopy in diagnostic centers has resulted in a dramatic increase in the number of reported viral enteric infections in man and animals in the last 10 yr. Enteric infection due to adenoviruses, astroviruses, coronaviruses, paramyxoviruses, parvoviruses, picornaviruses (caliciviruses), rotaviruses as well as some unidentified viral particles are described. The brief literature review on each of these virus families is supplemented with clinical cases submitted to the Texas Veterinary Medical Diagnostic Laboratory. Comparative aspects of viral infections between different animal species as well as man are discussed wherever possible.