The role of the veterinary diagnostic lab in the management of BRD.

Veterinary diagnostic labs (VDLs) are important service agencies providing essential diagnostic testing for a wide variety of domestic animal species as well as wildlife. They serve key roles in disease monitoring and diagnosis as well as surveillance for diseases of consequence. Of the many roles VDLs serve, one is being a member of the larger team of professionals dealing with the management of the bovine respiratory disease (BRD) complex. VDLs provide a number of services related to the management of BRD. These include disease outbreak investigation, abnormal morbidity characterization, routine monitoring, and biosecurity screening for a variety of infectious agents via methods such as necropsy and histopathology, bacterial culture, antimicrobial sensitivity testing, virus isolation, and serological assays. VDLs continue to look for better methods and assays as instrumentation technology also grows and improves. This is reflected in the growing proliferation of molecular-based assays that provide a high degree of sensitivity and specificity. Professional staff in VDLs work in collaboration with those in academia and private industry to conduct basic research focusing on a different aspect of the BRD complex. VDLs remain a primary source of the varied field-origin infectious agents associated with BRD that are used for research purposes.

Caecal worm, Aulonocephalus pennula, infection in the northern bobwhite quail, Colinus virginianus.

Parasitic nematodes that infect quail have been understudied and long been dismissed as a problem in quail management. Within the Rolling Plains ecoregion of Texas, an area that has experienced quail population "boom and bust" cycles and ultimately a general decline, the need to determine why Northern bobwhite (Colinus virginianus) populations are diminishing has increased in priority. Previously, caecal parasites have been documented to cause inactivity, weight loss, reduced growth, inflammation to the caecal mucosa, and even death. The caecal worm Aulonocephalus pennula is an intestinal nematode parasite that is commonly found within the caecum of quail, as well as many other avian species. In the Rolling Plains ecoregion, A. pennula has been documented to have as high as a 98% prevalence in bobwhite quail samples; however, the effect it has on its host is not well understood. The present study documents A. pennula causes no pathological changes within the caeca of the Northern bobwhite. However, there is concern for disruption of digestion and the possible implications of infection for wild bobwhite quail survival are discussed.

Glyphosate input modifies microbial community structure in clear and turbid freshwater systems.

Since it was commercially introduced in 1974, glyphosate has been one of the most commonly used herbicides in agriculture worldwide, and there is growing concern about its adverse effects on the environment. Assuming that glyphosate may increase the organic turbidity of water bodies, we evaluated the effect of a single application of 2.4 ± 0.1 mg l(-1) of glyphosate (technical grade) on freshwater bacterioplankton and phytoplankton (pico, micro, and nanophytoplankton) and on the physical and chemical properties of the water. We used outdoor experimental mesocosms under clear and oligotrophic (phytoplanktonic chlorophyll a = 2.04 µg l(-1); turbidity = 2.0 NTU) and organic turbid and eutrophic (phytoplanktonic chlorophyll a = 50.3 µg l(-1); turbidity = 16.0 NTU) scenarios. Samplings were conducted at the beginning of the experiment and at 1, 8, 19, and 33 days after glyphosate addition. For both typologies, the herbicide affected the abiotic water properties (with a marked increase in total phosphorus), but it did not affect the structure of micro and nanophytoplankton. In clear waters, glyphosate treatment induced a trend toward higher bacteria and picoeukaryotes abundances, while there was a 2 to 2.5-fold increase in picocyanobacteria number. In turbid waters, without picoeukaryotes at the beginning of the experiment, glyphosate decreased bacteria abundance but increased the number of picocyanobacteria, suggesting a direct favorable effect. Moreover, our results show that the impact of the herbicide was observed in microorganisms from both oligo and eutrophic conditions, indicating that the impact would be independent of the trophic status of the water body.

Characterization of human sperm N-acetylglucosaminidase.

N-acetylglucosaminidase (NAG) is particularly active in mammalian spermatozoa and appears to be involved in fertilization. Although it is assumed that this enzyme is acrosomal, previous results from our laboratory suggest the presence of NAG at the sperm plasma membrane level. The present study attempted to analyse the subcellular distribution of this enzyme in human spermatozoa. Sperm were incubated under different conditions and NAG activity measured in the soluble extracts and cell pellets using a specific fluorometric substrate. A significant proportion of NAG activity was released when sperm were incubated in culture medium, suggesting a weak association with the plasma membrane. This location was confirmed by western blot analysis of plasma membrane fractions and immunofluorescence on non-permeabilized sperm, which showed a positive signal mainly on the acrosomal domain. The distribution of NAG activity between plasma membrane and acrosome was analysed after cell disruption by freezing and thawing. Triton X-100 stimulated sperm and epididymal NAG activity but not the enzyme obtained from other sources. In addition, biotinylated human recombinant NAG was able to bind to human sperm. Finally, after sperm incubation under capacitating conditions, NAG total activity increased and the sperm enzyme lost its ability to be stimulated by Triton X-100. The possible connection of these results with sperm maturation, capacitation and NAG participation in primary binding to the zona pellucida, was discussed.

Interpretation of basic gross pathologic changes of the digestive tract.

The necropsy is a valuable diagnostic tool. When presented with a dead animal, it is not uncommon for the necropsy to be the springboard for the entire diagnostic evaluation. Not only is important information gained from gross examination of the organs but during necropsy, tissue and fluid samples for supportive tests--bacterial culture, antibiotic sensitivity, virus isolation, serology, parasite burden, and toxicologic and histopathologic studies--are collected. It is not essential for a veterinarian to be a pathologist to get good information from a necropsy. This article attempted to identify a number of basic lesions that occur with the most common diseases of the digestive tract of food animals. Additionally, associations between lesions and certain etiologies as well as diseases have been made so that when one identifies a particular lesion (in a live or dead animal), a prioritized list of possible differential diagnoses comes to mind. The necropsy does not stand alone or above the other sources of diagnostic information. The information gained from a necropsy must be correlated with the other information to arrive at either a specific diagnosis or a short list of possible diagnoses. The veterinarian must seek further input, in the latter situation, from additional clinical examinations, laboratory tests, or interviews with the client to arrive at the diagnosis.

Bovine viral diarrhea virus cytopathic and noncytopathic biotypes and type 1 and 2 genotypes in diagnostic laboratory accessions: clinical and necropsy samples from cattle.

One hundred three bovine samples submitted to the Oklahoma Animal Disease Diagnostic Laboratory (OADDL) that were positive for bovine viral diarrhea virus (BVDV) were typed by a nested reverse transcription-polymerase chain reaction for BVDV genotypes. These BVDV samples included supernatants from virus isolation (79), serums (17), and buffy coats (7). The biotype, cytopathic (CP) or noncytopathic (NCP), was determined by cell culture virus isolation. Twenty-eight of 103 samples were submitted for herd screening for BVDV, 32 from OADDL necropsy cases, and 43 from live cattle with varied clinical conditions. Two samples contained 2 bands indicating presence of both BVDV types 1 and 2. Of the 105 BVDV samples, 26 were type 1 CP strains (24.8%), 38 were type 1 NCP strains (36.2%), 10 were type 2 CP strains (9.5%), and 31 were type 2 NCP strains (29.5%). From the 105 BVDV isolates, NCP biotypes were isolated more frequently (69, 65.7%) than CP biotypes (36, 34.3%), and type 1 genotypes were more frequently isolated (64, 61.00%) than type 2 genotypes (41, 39.0%). The NCP strains were more common than CP in herd screening samples. Cattle with respiratory disease history at time of sampling had more NCP than CP biotypes and more type 1 than type 2 genotypes. Of the necropsy cases, more were type 1 than type 2 genotypes for the respiratory cases with fibrinous pneumonia, more were type 1 than type 2 genotypes in cattle with enteritis/colitis without systemic lesions, and more were CP than NCP biotypes in cattle with enteritis/colitis with systemic lesions. No CP biotype was isolated from serum samples.

Expression of the alpha6 chain of type IV collagen in glomerular basement membranes of healthy adult dogs.

OBJECTIVE: To evaluate expression of the alpha6 chain of type IV collagen in the glomerular basement membranes (GBM) of healthy dogs. SAMPLE POPULATION: Kidney specimens from 12 healthy dogs. For comparison, kidney specimens from 8 human subjects between 25 and 83 years old also were evaluated. PROCEDURE: Sections were immunolabeled with a monospecific antibody that cross-reacts with human and canine alpha6(IV) chains and examined by means of fluorescence microscopy. RESULTS: Immunolabeling of the alpha6(IV) chain was not observed in GBM of 6 dogs < or = 30 months old but was observed in GBM of the remaining 6 dogs, all of which were > or = 45 months old. Expression of the alpha6(IV) chain was not observed in GBM of the human subjects, regardless of the age of the subject. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that the alpha6(IV) chain is expressed in GBM of healthy dogs, but the expression is age-dependent. Composition and structural organization of type IV collagen in the GBM of healthy adult dogs is different from that described for other species.

Small employers and health benefits: findings from the 2000 Small Employer Health Benefits Survey.

Many small employers (between two and 50 workers) are making decisions about whether to offer health benefits to their workers without being fully aware of the tax advantages that can make this benefit more affordable. Fifty-seven percent of small employers did not know that they can deduct 100 percent of their health insurance premiums. Nearly one-half of small employers are not aware that workers who purchase health insurance on their own generally cannot deduct 100 percent of their health insurance premiums. Small employers are largely unaware of the laws that have been enacted by nearly all states and the federal government with the intent of making health insurance more accessible and more affordable for many small employers. More than 60 percent did not know that insurers may not deny health insurance coverage to small employers even when the health status of their workers is poor. Most employers offer sound business reasons for offering health benefits to workers. Many have found that it helps with employee recruitment and retention, increases productivity, and reduces absenteeism. Nearly 50 percent of the employers offering dependent (family) coverage report that the workers do not take coverage for their dependents because the dependents have coverage from somewhere else. Twenty-seven percent report their employees decline dependent coverage because they cannot afford the premiums. Many small employers that do not offer health benefits are potential purchasers. Twelve percent are either extremely or very likely to start offering health benefits in the next two years, and 17 percent are somewhat likely to start offering health benefits. A number of factors would increase the likelihood that a small business would seriously consider offering a health benefits plan. Two-thirds of small-business owners said they would seriously consider offering health benefits if the government provided assistance with premiums. Almost one-half would consider doing so if insurance costs fell 10 percent. In addition, one-half would be more likely to seriously consider offering a health benefits plan if employees demand it. Many small employers with health benefits have recently switched health plans, and 34 percent report that they did so within the past year. Affordability for the employer and the worker is clearly a critical factor affecting the likelihood of switching health plans. Nearly all employers who have switched health plans within the past five years cite cost as the main reason. One-third of companies offering health benefits think they will change coverage, and 5 percent think they would drop coverage if the cost of health insurance were to increase by 5 percent.

Retirement Confidence Survey 2000 including results from the RCS Minority Survey and the Small Employer Retirement Survey.

The year 2000 represents the 10th anniversary of the Retirement Confidence Survey (RCS), and the third year for the Minority RCS and Small Employer Retirement Survey (SERS). Key RCS findings over the past 10 years include: The fraction of workers saving for retirement has trended upward, and today 80 percent of households report that they have begun to save. The fraction of workers who have attempted to calculate how much they need to save for retirement has risen noticeably over the past several years. Today, 56 percent of households report that they have attempted the calculation. One-half of workers who have attempted such a calculation report that it has changed their behavior, such as saving more and/or changing where they invest their retirement savings. Workers who have done the calculation appear to be in better shape regarding their retirement finances. Worker confidence in the ability of Social Security to maintain benefit levels bottomed out in 1994 and 1995. Workers today are just as confident as they were in 1992, although the majority remain not confident in Social Security. Regarding overall retirement confidence, Hispanic-Americans tend to be the least confident among the surveyed minority groups that they will have enough money to live comfortably throughout their retirement years. Key SERS findings include: While cost and administrative issues do matter to small employers, they are not the primary reasons for low plan sponsorship rates. Employee-related reasons are most often cited as the most important factor for not offering a retirement plan. Business-related reasons, such as profitability, are also a main decision-driver. It is important to note what small employers without plans do not know about plan sponsorship. Small employers that do sponsor a retirement plan report that offering a plan has a positive impact on both their ability to attract and retain quality employees and the attitude and performance of their employees. The survey results indicate that many small company nonsponsors may not be aware of such potential business benefits from plan sponsorship. In addition, many nonsponsors are unaware of the plan options available to them, in particular the ones created specifically for small employers, such as SIMPLE and SEP retirement plans. Therefore, some small employers may be making a premature decision not to sponsor a plan based on incomplete information.

Nested reverse transcriptase-polymerase chain reaction (RT-PCR) for typing ruminant pestiviruses: bovine viral diarrhea viruses and border disease virus.

A nested reverse transcription (RT) polymerase chain reaction (PCR) assay was evaluated for differentiating reference bovine viral diarrhea virus (BVDV) strains, BVDV from diagnostic accessions, modified-live virus (MLV) BVDV strains in bovine viral vaccines, and a reference border disease virus (BDV). The detection level of this assay was compared to viral infection in cell culture. The PCR assay was used to distinguish 3 ruminant pestiviruses, types 1 and 2 BVDV, and type 3 BDV. The consensus (first) PCR assay detected all 3 ruminant pestiviruses, a result of the shared sequence homology. The consensus PCR product was subjected to a second (nested) PCR which used type-specific primers. The nested PCR was able to differentiate the 3 ruminant pestiviruses. Viral stocks of BVDV were diluted 10-fold and processed for the 2-step PCR assay. The sensitivity of this 2-step PCR assay was compared to viral infectivity in cell culture based on identical volumes of the system tested (cell culture assay and processing for RNA). The RT-PCR type-specific assay differentiated BVDV laboratory reference strains (12), diagnostic laboratory isolates (15), 2 MLV BVDV vaccine strains, and a BDV strain. The 30 ruminant pestiviruses typed included: (1) 27 reference strains and diagnostic laboratory isolates; 18 cytopathic (CP) type 1 strains, 3 CP type 2 strains, 3 noncytopathic (NCP) type 1 strains, and 3 NCP type 2 strains; (2) 2 MLV strains, type 1; and (3) 1 CP BDV type 3. The PCR assay had a detection limit of 10 TCID50/0.025 mL of virus when 3 separate BVDV were tested. This 2 step RT-PCR assay would be useful for the typing of ruminant pestiviruses, particularly BVDV isolates from the diagnostic laboratory.

Hypercalcemia associated with granulomatous disease in a cat.

A 6-year-old cat was examined because of recurrence of a draining mass involving skin and subcutaneous tissues of the caudoventral aspect of the abdomen. Previous treatment included administration of antimicrobial drugs and corticosteroids and surgical excision. Atypical mycobacteria were seen during cytologic examination of biopsy specimens of the mass; Nocardia sp was cultured. While hospitalized, the cat developed hypercalcemia and was found to have high serum calcitriol concentrations. Treatment consisted of administration of ciprofloxacin and trimethoprim-sulfadiazine because of the infection and administration of sodium chloride solution, furosemide, and calcitonin because of the hypercalcemia. The cat recovered.

Pythiosis of the digestive tract in dogs from Oklahoma.

Enteric pythiosis was diagnosed in nine dogs in Oklahoma. Eight dogs had anorexia and weight loss. Two of these dogs had diarrhea; two dogs exhibited vomiting and diarrhea; and one dog had vomiting. One dog presented with dysphagia. Seven dogs had either a palpable or radiographically visible abdominal mass. These seven dogs had localized regions of mucosal ulceration and thickened gastric or intestinal walls with some involvement of the adjacent mesentery or omentum. Two dogs had enlarged regional mesenteric lymph nodes. One dog that presented with dysphagia had an oropharyngeal mass involving the larynx and cranial esophagus. Microscopically, there was transmural chronic sclerosing and granulomatous to pyogranulomatous inflammation with arteritis. Pythium spp. were identified in all specimens by immunohistochemistry.

Evaluation of hepatic changes and weight gains in sheep grazing Kochia scoparia.

Sixteen Western Whiteface ewes were divided into 2 groups to determine the effects of plant maturity on liver function and weight gains. They were allowed to graze a greater than 95% pure stand of Kochia scoparia for 72 or 55 d. Four additional sheep (controls) were placed on weedy Bermuda grass pasture with the same water supply as the kochia-fed sheep. Body weights were determined on June 5, 1996 and on removal from the kochia pasture. Blood samples were collected at approximately 7-d intervals for serum chemistry profiles. Kochia scoparia plant samples were also randomly collected at 5-6 w intervals, oven dried, identified by date of collection and stored for later nutrient, oxalate, nitrate and sulfate analysis. Liver biopsies were performed pre-, mid- and post-study to assess morphologic changes. An almost exclusive diet (> 95%) of Kochia scoparia resulted in minimal elevations in serum GGT, suggesting mild hepatocellular injury, but was not associated with overt hepatic lesions or clinical disease. Other serum chemistry measurements were within normal ranges. Unlike for other domestic animal species, Kochia scoparia may be a useful grazing forage for sheep, offering little risk of toxicosis.

New form of X-linked dominant hereditary nephritis in dogs.

OBJECTIVE: To determine features of a new form of hereditary nephritis (HN) in dogs. ANIMALS: Parents and 16 first-generation offspring (8 males, 8 females). PROCEDURE: Adolescent dogs that developed renal failure were euthanatized and necropsied. Unaffected dogs were monitored until they were at least 2 years old. Studies included light and electron microscopy of kidneys obtained from affected and unaffected dogs and immunolabeling for collagen-IV chains in renal and epidermal basement membranes (BM). The nucleotide sequence of a portion of exon 35 of the COL4A5 gene was determined in genomic DNA isolated from affected and unaffected males. RESULTS: 7 of 8 male and 2 of 8 female offspring had proteinuria and juvenile-onset chronic renal failure, which progressed more rapidly in the males. Labeling for alpha3-alpha6(IV) chains was completely absent in renal BM of affected males and segmentally absent in affected females. Expression of alpha1-alpha2(IV) chains in glomerular BM (GBM) of affected dogs was increased. Labeling for alpha5-alpha6(IV) chains in epidermal BM was absent in affected males and segmental in affected females. Ultrastructural changes characteristic of HN were observed in GBM of affected dogs. The sequence of exon 35 of COL4A5 was normal in affected dogs. CONCLUSIONS: This renal disease is an example of X-linked dominant HN, with typical abnormalities of GBM ultrastructure and alpha(IV) chain expression. CLINICAL RELEVANCE AND IMPLICATIONS FOR HUMAN MEDICINE: Dogs with this naturally acquired progressive renal disease can be used to investigate the pathogenesis and treatment of similar disorders in human beings and dogs.

A model of autosomal recessive Alport syndrome in English cocker spaniel dogs.

BACKGROUND: Dogs with naturally occurring genetic disorders of basement membrane (type IV) collagen may serve as animal models of Alport syndrome. METHODS: An autosomal recessive form of progressive hereditary nephritis (HN) was studied in 10 affected, 3 obligate carrier, and 4 unaffected English cocker spaniel (ECS) dogs. Clinical, pathological, and ultrastructural features of the disease were characterized. Expression of basement membrane (BM) proteins was examined with an immunohistochemical technique using monospecific antibodies. RESULTS: Affected dogs had proteinuria and juvenile-onset chronic renal failure. Glomerular basement membrane (GBM) thickening and multilamellation typical of HN were observed in all renal specimens obtained from proteinuric dogs, and severity of GBM ultrastructural abnormalities varied with the clinical stage of disease. Expression of alpha3(IV) and alpha4(IV) chains was totally absent in the kidney of affected dogs. Expression of alpha5(IV) and a6(IV) chains was normal in Bowman's capsule, collecting tubular BM and epidermal BM of affected dogs. The alpha5(IV) chain was not expressed in distal tubular BM of affected dogs. Expression of alpha5(IV) chains was markedly reduced but not absent, and expression of alpha6(IV) chains was present in GBM of affected dogs. Expression of alpha1-alpha2(IV) chains in GBM of affected dogs was increased. Features of obligate carriers were similar to those of unaffected dogs. CONCLUSIONS: We conclude that HN in ECS dogs is a naturally occurring animal model of autosomal recessive Alport syndrome. However, it differs from human disease in the persistence of alpha5(IV) chains in GBM and in the appearance of a6(IV) chains in GBM.

Early diagnosis of familial nephropathy in English cocker spaniels.

Two litters of English cocker spaniels (ECSs) produced by familial nephropathy (FN) carriers were evaluated to characterize the early features of this disease. Three puppies developed FN. Proteinuria, which began when these puppies were five-to-eight months old, was the first abnormality detected. Proteinuria persisted while each puppy's growth rate slowed, and renal function gradually deteriorated. The interval from onset of proteinuria to development of azotemia was two-to-nine months. Characteristic glomerular capillary basement membrane (GCBM) lesions were seen with transmission electron microscopy (TEM) of renal biopsy specimens obtained during this interval. Ultrastructural GCBM lesions progressed substantially during the interval from biopsy to necropsy. However, routine light microscopic findings did not allow definitive diagnosis of FN in either biopsy or necropsy specimens. Detection of FN can be accomplished by screening at-risk ECSs for proteinuria. Renal biopsies are required to confirm the diagnosis in dogs for which proteinuria cannot be explained otherwise. Percutaneous needle biopsy specimens sufficient for TEM must be used to examine the GCBM to make a definitive diagnosis.

Cobalt 60 radiotherapy for treatment of squamous cell carcinoma of the nasal cavity and paranasal sinuses in three horses.

Three adult horses underwent aggressive treatment of squamous cell carcinoma of the nasal cavity and paranasal sinuses, using course-fractionated cobalt 60 radiotherapy. Squamous cell carcinoma of the nasal cavity and paranasal sinuses is not commonly diagnosed in horses. Historically, horses with this type of neoplasm have not been treated or have undergone some form of surgery. The prognosis for long-term survival or cure has been poor. Long-term results of cobalt 60 radiotherapy were good to excellent and exceeded those usually reported for horses treated surgically. On the basis of these results, use of radiotherapy for these neoplasms is recommended.