Pet dogs as sentinels for environmental contamination.

The presence of environmental contaminants in air, water and food may pose significant health risks to the exposed human population. However, problems associated with assessing chronic exposure to low doses of environmental chemicals, multiple exposure routes, diseases with long latency periods, and non-specific health outcomes make it difficult to conduct the appropriate human epidemiologic studies. It may be useful to complement human epidemiology with animal studies. Animals monitored or evaluated in situ for the appropriate suite of endpoints can provide information about both exposure levels and potential adverse health effects. Animals have served as sentinel indicators for health effects associated with a number of environmental exposures, including pesticides and asbestos. Pet dogs may be particularly valuable sentinels because they share the human environment. In addition, dogs respond to many toxic insults in ways analogous to humans, they have physiologically compressed life spans, and they are free from some important lifestyle risk factors for disease. An example of how pet dogs may be used as sentinels for potential human health hazards involves a study of the genotoxic effects resulting from exposure to a mixture of chemicals from nearby Superfund sites. We conducted a cross-sectional study of exposed dogs (living in the community with the Superfund sites) and controls (living in a nearby community). The pet owners completed a questionnaire, and we collected a blood sample from each dog. The blood samples were analyzed for standard clinical parameters and assays for possible genotoxic effects (peripheral blood lymphocyte micronucleus frequency and lymphocyte subtyping). Pet dogs living near the Superfund sites had a higher micronucleus frequency than control animals, suggesting that the dogs may have been exposed to environmental contaminants from these sites.

Thrombocytopenia associated with neoplasia in dogs.

Ten percent (214/2,059) of all dogs with cancer at North Carolina State University Veterinary Teaching Hospital had thrombocytopenia. The thrombocytopenia was associated with infectious/inflammatory etiologies in 4%, miscellaneous disorders (therapy, bone marrow failure, disseminated intravascular coagulation) in 35%, and neoplasia without identifiable secondary factors in 61% of cancer-bearing dogs. Classifying these dogs by tumor groups revealed the following proportionate ratios: lymphoid, 29%; carcinoma, 28%; sarcoma, 20%; hemic neoplasia, 7%; multiple, 5%; unclassified, 3%; benign, 3%; brain, 3%; and endocrine, 3%. Dogs with hemangiosarcoma, lymphoma, and melanoma were at increased risk of developing thrombocytopenia. Cytotoxic therapy was the major factor increasing the risk of thrombocytopenia in dogs with melanoma. Golden Retrievers were the only breed recognized with a predisposition to develop thrombocytopenia. If thrombocytopenia is identified in a dog with cancer, we recommend thorough evaluation of the coagulation system before surgery or therapy, and careful consideration of the risks and potential benefits of myelosuppressive or L-asparaginase therapy.

Blood gas tensions, acid-base status, heart rates, and venous profiles in exercising horses with laryngeal hemiplegia before and after corrective surgery.

The physiologic effects of exercise were studied in four horses with complete laryngeal hemiplegia. Right carotid arteries were surgically elevated to a subcutaneous position for percutaneous catheterization. Each horse was fitted with a device designed to obtain multiple arterial samples while the horse was exercised over a 1.6-km course. After each horse completed 10 test gallops, the laryngeal hemiplegia was treated using a laryngeal prothesis and ventriculectomy. The horses were then reconditioned, and the exercise test and sampling were repeated. Horses with laryngeal hemiplegia became acidotic, hypoxic, and hypercapnic compared to normal horses. Surgical treatment improved blood gas and acid-base status, but the values were not equivalent to those in normal horses similarly tested.

Instrumentation of exercising thoroughbreds to determine blood gas tensions and acid-base status.

A device was constructed of easily obtained medical supplies, and hardware and could be used to obtain multiple arterial samples when manually triggered. The right carotid arteries in five normal horses were surgically elevated, thereby permitting percutaneous cannulation. Each horse was galloped on a 1.6-km test track at approximately 500 m/min, and the rider triggered the mechanism at each 0.4-km mark. Each horse underwent 10 test gallops, and a mean and standard error was determined for each sampling mark including preexercise and postexercise samples. The results indicated that horses ridden under the aforementioned conditions became acidemic and hypoxic.

Epidemiological studies of congo red Escherichia coli in broiler chickens.

This prospective cohort study was designed to confirm the association between Congo red binding Escherichia coli (CREC) and E. coli air sacculitis in commercial broilers. It was also designed to evaluate CREC as an air sacculitis risk factor and to explore the CREC relationship to other air sacculitis risk factors (poultry house temperature, air-ammonia levels, and presence of other diseases). In addition, this study was used to assess a possible role of the broiler-breeder flocks and hatchers in the spread of CREC air sacculitis. Congo red E. coli-associated airsacculitis risk was based on CREC exposure of the chicks in the hatchers. Breeder flocks with greater than 30 CREC colonies/plate from hatcher air sampling tests were placed in the high risk group; flocks with less than five CREC colonies/plate were placed in the low risk group. Increased risks of death due to air sacculitis (RR = 2.26), and increased death rates due to CREC air sacculitis (RR = 9.45) in high-risk flocks, identified CREC as an important air sacculitis risk factor. The attributable risk percent of CREC airsacculitis from hatcher exposure of CREC was 89.4%, pointing to the hatcher as the source of CREC infection. The association of specific broiler-breeder flocks to high levels of CREC in the hatchers, and subsequent air sacculitis, suggests that the broiler-breeders are the ultimate source of CREC.

Evaluation of an indirect enzyme-linked immunosorbent assay for screening antibody against aflatoxins.

Enzyme-linked immunosorbent assay screening of antibody produced against aflatoxin was accomplished by a new and simple procedure. To demonstrate the new indirect ELISA technique used, antibody against aflatoxin M1 was produced in female BALB/CJ mice by immunization with an aflatoxin M1-bovine serum albumin conjugate. Instead of coating test-plate wells with purified antibody (direct ELISA) or synthesizing a second protein-aflatoxin conjugate (aflatoxin M1-poly-L-lysine) to coat test-plate wells, wells were coated with the readily available aflatoxin M1-bovine serum albumin and aflatoxin B1-bovine serum albumin. This method, applicable for any aflatoxin conjugated by the common cyclopentano-carboxymethoxyl-oxime technique, eliminates the more time-consuming and technically difficult portions of earlier direct and indirect ELISA. The new technique can be valuable in continued efforts toward development of new and improved immunoassays against aflatoxin metabolites.

Success rates of unilateral vs. bilateral cataract extraction in dogs.

Postoperative results of 113 unilateral and 77 bilateral extracapsular cataract extractions (EC-CEs) in dogs were evaluated retrospectively. Restoration or improvement of functional vision was achieved in 79.6% of the eyes in dogs with unilateral extraction and 85.7% of the eyes in dogs with bilateral extractions at weeks 4 to 6. Complications occurring 6 weeks to 9 months after lens extraction lessened the surgical success rate in both groups. Twenty-six percent of the dogs in which bilateral lens removal was performed suffered complications resulting in surgical failure in one eye. When using the criterion that one or both treated eyes had functional vision, a short-term success rate of 98.7% was found for bilateral extractions.

Risk factors for Haemobartonella felis infection in cats.

A seroepidemiologic survey for Haemobartonella felis infection in cats of Wake County, NC was undertaken. To help assess risk factors, cat owners completed a 10-item questionnaire. Additionally, blood samples were obtained for determination of H felis presence, FeLV infection, and anemia. Prevalence rates for H felis presence were as follows: all cats, 4.9% (6/123); healthy cats, 3.6% (3/83); and ill cats, 7.5% (3/40). The estimated relative risk for haemobartonellosis was also increased in cats with any of the following: anemia, FeLV-positive status, lack of vaccinations, history of catbite abscesses and/or anemia, age less than or equal to 3 years, or outdoor-roaming status. The sex, breed, number of cats in the household, or presence of fleas were not significant factors, although ill male cats had a greater estimated relative risk for haemobartonellosis.

Platelet aggregation in dogs experimentally infected with Rickettsia rickettsii.

Platelet aggregation studies were performed on nine Beagle dogs experimentally infected with Rickettsia rickettsia. Platelets from dogs with Rocky Mountain spotted fever tended to be more aggregable than controls.

Preparation of protein conjugatable aflatoxin oxime derivative from significantly reduced starting quantities.

A modification of an existing technique for the preparation of aflatoxin B1-(0-carboxymethyl) oxime is presented which allows for a significantly reduced starting amount of aflatoxin. About 80% of the aflatoxin was converted to its oxime. The new technique will be particularly valuable when protein conjugatable oximes of more expensive aflatoxin metabolites, such as aflatoxin M1, are required for immunoassay production.

Transendoscopic neodymium:yttrium aluminum garnet laser irradiation in horses.

A neodymium:yttrium aluminum garnet (Nd:YAG) laser was used to study effects of applying laser irradiation transendoscopically to the corniculate process of the arytenoid cartilage in horses. Dosimetry was established initially in vitro in 10 corniculate cartilages that were irradiated and examined histologically to determine penetration depths at selected power settings. Eleven horses were given xylazine IV and butorphoral tartrate IV, and their left ventricle and corniculate process were irradiated. Six horses had left laryngeal hemiplegia and were euthanatized and necropsied 14 weeks after laser application and evaluation for upper airway stridor. Endoscopy was performed in the 5 other horses; they were euthanatized and necropsied at selected intervals to characterize the healing process. Healing was by second intention and was complete at 14 weeks. Two horses developed buds of granulation tissue along the laser incision, which resolved after a second laser application. Scar tissue formation resulted in left of midline displacement of the dorsal portion of the right corniculate process. The left ventricle healed without complications and was totally ablated. All horses had inspiratory stridor when exercised 14 weeks after laser irradiation.

Epidemiologia de las enfermedades del ganado bovino en Suriname / Epidemiology of cattle diseases in Suriname

The prevalence of certain cattle diseases in Suriname was studied over the period June-August 1985. The diseases were selected for their economic importance and association observed in the cattle with respiratory diseases, reproductive inefficiency, and neonatal mortality. Random samples were taken at two cattle-raising ranches, a dairy farm, and an abattoir in the District of Suriname. The study included a total of 478 animals, which were tested by indirect immunofluorescence for each of the diseases selected. Basically the serologic study revealed the presence of brucellosis, bovine viral diarrhea, parainfluenza 3, bovine infectious rhinotracheitis, and bovine coronavirus but not respiratory syncytial virus. The prevalence of parainfluenza 3 and bovine viral diarrhea was low compared with rates in other countries. It is recommended that a system, specially designed to meet the needs of this country, be established for the ongoing surveillance of data on animal health

Epidemiologic survey of bovine diseases in Suriname.

A seroepidemiologic survey of cattle diseases was undertaken in Suriname in 1985 to help assess the livestock disease situation in that country. The six diseases covered by the survey were bovine coronavirus infection, bovine rhinotracheitis, bovine virus diarrhea, brucellosis, parainfluenza-3 infection, and respiratory syncytial virus infection. The results indicated relatively low prevalences of these diseases compared to the prevalences found in most developed countries. The reasons for this are uncertain, but the finding suggests that the cattle population in Suriname could lack extensive exposure to these diseases and so could be highly susceptible to them. In addition, the evident need for more thoroughgoing survey data points up the need to establish a continuous animal data health monitoring system in Suriname--as well as in other developing countries where there is a need to objectively assess the livestock disease picture.

Seroepidemiologic survey of feline immunodeficiency virus infection in cats of Wake County, North Carolina.

Feline immunodeficiency virus (FIV) antibodies were detected in 9 of 123 (7.3%) cats. More clinically ill cats had titers to FIV than did healthy cats (15% vs 3.6%). Previous or current illnesses in these FIV-positive cats included urinary bladder disease, anemia, cat-bite abscesses, bacterial infections, bleeding disorders, diabetes mellitus, and chronic respiratory tract disease. All FIV-positive cats were males, with mean age of 6.0 years (range, 1 to 11 years). Half (n = 3) of the clinically ill FIV-positive cats were concurrently seropositive for FeLV antigen. Three of the ill cats were euthanatized or died 1 month after initially testing, whereas the remaining 3 ill cats and the 3 healthy FIV-positive cats were healthy 1 year after initial testing. Antibody titer to FIV persisted in 4 of 5 cats, but serotest results were equivocal in 1 cat evaluated 1 year later.

Experimental cryptosporidiosis and infectious bursal disease virus infection of specific-pathogen-free chickens.

Specific-pathogen-free chickens orally inoculated at 4 days of age with a moderately pathogenic vaccine strain of infectious bursal disease virus (IBDV) and/or at 5 days of age with Cryptosporidium baileyi oocysts remained free of overt clinical signs throughout a 16-day period postinoculation (PI). The prepatency period for C. baileyi oocyst shedding was shorter in chickens receiving higher numbers of oocysts, but once shedding was detected, there were no obvious differences in shedding patterns among groups receiving 10(3) through 10(6) oocysts. On days 8 and 16 PI, cryptosporidia were located primarily in the bursae of Fabricius. IBDV exposure was associated with bursal follicle atrophy, whereas C. baileyi infection resulted in bursal epithelial hypertrophy and hyperplasia, mild follicle atrophy, and heterophil infiltration of the bursal mucosa. Examination of experimental groups of 30 birds each indicated that concurrent infection with both agents resulted in more severe bursal lesions, more infected birds, and greater numbers of cryptosporidia in infected tissues. At the termination of the trial, 16 days PI, Cryptosporidium infection was associated with a 6% decrease in mean body weight compared with controls.

Kidney biopsy: a nonlethal method for diagnosing Yersinia ruckeri infection (enteric redmouth disease) in rainbow trout (Salmo gairdneri).

The sensitivity and specificity of kidney biopsy were 93 and 88%, respectively, for detecting Yersinia ruckeri infection in rainbow trout (Salmo gairdneri). There was no statistically significant difference between results obtained by kidney biopsy and those obtained by necropsy, the standard method for isolation of this agent from the kidney. One hundred percent of conscious fish that were tested survived the procedure.

An epidemiological investigation associating aflatoxin M1 with milk production in dairy cattle.

An attempt was made to utilize the analysis for aflatoxin M2 in milk, instead of aflatoxin B1 in feed for a pilot epidemiological study addressing the association of M1 levels and various production parameters. Four dairy farms, representing above average to below average management practices, were identified with 10 animals being randomly selected from each farm for this study. Milk samples and production data were evaluated from these animals in order to gain insight into the possible effects of low level mycotoxin ingestion on production and to test whether or not this approach offered potential for future epidemiological studies. Feed samples were basically negative for the presence of aflatoxin B1, yet milk analysis revealed the presence of M1 in a large percentage of the animals. Further, the M1 levels appeared to be associated with a decrease in daily milk production. This study indicates that employing M1 analysis in milk for epidemiological investigations of low level mycotoxin ingestion effects, instead of B1 feed analysis, is feasible and offers a potential for more definitive studies in this area.

Clinical, hematologic, and humoral immune response in female dogs inoculated with Rickettsia rickettsii and Rickettsia montana.

Female Beagles were inoculated intradermally with a sublethal dose of Rickettsia rickettsii and R montana. Three dogs (group 1) were inoculated with 2 X 10(2) plaque-forming units (PFU) of R rickettsia and were treated with tetracycline beginning on postinoculation day (PID) 12; 3 dogs (group 2) were inoculated with 2 X 10(2) PFU of R rickettsii but were not treated; 3 dogs (group 3) were inoculated with 2 X 10(2) PFU of R montana. Group-3 dogs failed to seroconvert and were inoculated a second time on PID 68. Groups 1 and 2 dogs inoculated with R rickettsii became depressed and developed occasional inappetence, fever, hematochezia, and ocular lesions. These dogs had a decrease in PCV and RBC count, an initial decrease in WBC count followed by leukocytosis, and a decrease in platelet count. Group-3 dogs inoculated with R montana remained healthy. After R rickettsii inoculation, the serologic response to spotted fever group (SFG) rickettsial antigens (R rickettsii, R rhipicephali, R montana, and R bellii) was similar. The antibody response to R rickettsii was first detected on PID 9, with peak titers reached by PID 20. Serum titers to R rickettsii remained stable or decreased one dilution through PID 120. Of 4 SFG rickettsial antigens, the highest serologic response was to R rickettsii. A cross-reacting antibody response with R rhipicephali and R montana was nearly identical and was only slightly less than the response to R rickettsii. Cross-reacting antibodies to R belli were of lower mean titer and of shorter duration than were cross-reacting antibodies to other SFG rickettsiae.(ABSTRACT TRUNCATED AT 250 WORDS)