A network model of H5N1 avian influenza transmission dynamics in domestic cats.

Naturally occurring cases of influenza in cats owing to the H5N1 strain have been reported in several countries. A cat reservoir of H5N1 in the United States could provide an environment for zoonotic disease spread to humans. This scenario was the impetus to develop a model to study potential transmission of H5N1 virus in domestic cats utilizing information on cat ownership and cat-cat interaction patterns, in addition to biological properties of the virus. The roaming behaviour of cats significantly influenced epidemic dynamics, as demonstrated by the simulation results from this model. A better understanding of the behaviour of domestic cats and the H5N1 influenza virus can be used to predict epidemic dynamics following the introduction of H5N1 virus into the United States and to develop effective strategies to prevent virus transmission to both cats and humans.

Reduction in DNA damage in brain and peripheral blood lymphocytes of elderly dogs after treatment with dehydroepiandrosterone (DHEA).

Steady state levels of DNA damage are substantial in vertebrate animals as a consequence of exposure to endogenous and environmental mutagens. DNA damage may contribute to organismal senescence and an increased risk for specific age-related diseases. In this study, we determined if treatment with the neuroactive adrenal steroid, dehydroepiandrosterone (DHEA), which exhibits antioxidant and anticarcinogenic properties in rodents, would reduce DNA damage in the brain and peripheral blood lymphocytes (PBLs) of elderly dogs. Elderly male dogs, physiologically equivalent to 59-69-year-old men, were randomly assigned to receive no treatment (n=9 dogs) or DHEA at 100mg/kg PO daily (n=8 dogs). Extent of DNA damage in brain cells and PBLs was measured using alkaline comet assay. The effect of DHEA treatment on the susceptibility of PBLs to H(2)O(2)-induced DNA damage was also measured. We found that elderly male dogs receiving daily DHEA treatment for 7 months had significantly less DNA damage detectable in their brain compared to age-matched control dogs. After 7 months treatment, DHEA-treated dogs also had a significant reduction in DNA damage in PBLs compared to pre-treatment levels. We also found that PBLs of dogs treated with DHEA were more resistant to H(2)O(2)-induced DNA damage than PBLs of untreated dogs. Our results did not show that basal DNA damage in PBLs was strongly correlated with DNA damage within the brain. The results of this study suggest that DHEA supplementation can significantly reduce steady state levels of DNA damage in the mammalian brain. Further evaluation of DHEA as a neuroactive agent and its effects on DNA damage and gene expression in other tissues and species is warranted.

Epidemiologic features of pet evacuation failure in a rapid-onset disaster.

OBJECTIVE: To describe epidemiologic features of pet evacuation failure after a hazardous chemical spill in which residents had no warning and only a few hours notice to evacuate. DESIGN: Cross-sectional study. SAMPLE POPULATION: Pet-owning households that evacuated from a hazardous chemical spill with (n = 119) or without (122) their pets. Procedures-Evacuees were surveyed by mail. RESULTS: 261 of 433 (60.3%) dogs and cats in 241 households were not evacuated. Of the 241 households, 119 (49.4%) evacuated with their pets, 98 (40.7%) evacuated without them but later attempted to rescue them, and 24 (10.0%) neither evacuated their pets nor attempted to rescue them. Pet evacuation failure was most common in households that thought the evacuated area was safe for pets. Risk of pet evacuation failure increased in households with many animals, low pet attachment and commitment scores, and low levels of preparedness. Cat evacuation failure was associated with not having cat carriers. Nearly 80% of households that evacuated with their pets found accommodation with friends and family. CONCLUSIONS AND CLINICAL RELEVANCE: Pet evacuation failure was common and jeopardized pets' health and well-being. Logistical challenges to transporting pets were substantial contributors to pet evacuation failure, whereas not knowing where to house a pet was only a minor concern. Most pet owners seemed self-reliant and acted appropriately towards their pets. Such self-reliant behavior by pet owners should be encouraged prior to disasters as part of an evacuation plan for households.

Risk factors for pet evacuation failure after a slow-onset disaster.

OBJECTIVE: To determine risk factors for pet evacuation failure during a flood. DESIGN: Cross-sectional survey. SAMPLE POPULATION: 203 pet-owning households in a flooded region. PROCEDURES: Persons under evacuation notice because of a flood were interviewed by use of a random telephone survey. RESULTS: 102 households evacuated with their pets, whereas 101 households evacuated without their pets. Low pet attachment and commitment scores were significantly associated with a greater chance of pet evacuation failure. Risk of pet evacuation failure and lower attachment and commitment scores were also associated with pet management practices prior to the disaster, such as dogs being kept outdoors most of the time or owners not having carriers for their cats. More than 90% of owners made housing arrangements for their pets without assistance. CONCLUSIONS AND CLINICAL RELEVANCE: Predictors of pet evacuation failure are usually present before a disaster strikes and are potentially modifiable. Mitigation of pet evacuation failure should focus on activities that reinforce responsible pet ownership and strengthen the human-animal bond, including socializing dogs, attending dog behavior training classes, transporting cats in nondisaster times, and seeking regular preventive veterinary care. Most pet owners are self-reliant in disasters, and this behavior should be encouraged.

Evaluation of dual energy x-ray absorptiometry for in situ measurement of bone mineral density of equine metacarpi.

OBJECTIVE: To determine the accuracy and precision of dual energy x-ray absorptiometry (DEXA) for measuring bone mineral density in horses in situ. Sample Population-12 randomly selected forelimbs from 12 horses. PROCEDURE: Metacarpi were scanned in 2 planes and DEXA measurements obtained for 6 regions of interest (ROI). Each ROI was isolated and bone density measured by Archimedes' principle. Linear regression analysis was used to determine the correlation between the 2 measurements at each ROI. An additional metacarpus was measured 10 times to determine the coefficient of variation for both techniques. RESULTS: Dual energy x-ray absorptiometry and bone density were significantly associated at multiple ROI. The addition of age, weight, and soft tissue or bone thickness improved these associations. Repeated measurements had a low coefficient of variation. CONCLUSIONS AND CLINICAL RELEVANCE: Dual energy x-ray absorptiometry can be used to accurately and precisely measure the bone density in the equine metacarpus. Dual energy x-ray absorptiometry appears suitable for serial in vivo measurement of bone density of the equine metacarpus. Dual energy x-ray absorptiometry may be used for studies to evaluate the effects of diet or drugs on bone density or density changes from bone remodeling that develop prior to stress fractures.

Highlights of human toxocariasis.

Human toxocariasis is a helminthozoonosis due to the migration of Toxocara species larvae through human organism. Humans become infected by ingesting either embryonated eggs from soil (geophagia, pica), dirty hands or raw vegetables, or larvae from undercooked giblets. The diagnosis relies upon sensitive immunological methods (ELISA or western-blot) which use Toxocara excretory-secretory antigens. Seroprevalence is high in developed countries, especially in rural areas, and also in some tropical islands. The clinical spectrum of the disease comprises four syndromes, namely visceral larva migrans, ocular larva migrans, and the more recently recognized "common" (in adults) and "covert" (in children) pictures. Therapy of ocular toxocariasis is primarily based upon corticosteroids use, when visceral larva migrans and few cases of common or covert toxocariasis can be treated by anthelmintics whose the most efficient appeared to be diethylcarbamazine. When diagnosed, all of these syndromes require thorough prevention of recontamination (especially by deworming pets) and sanitary education.

Human and pet-related risk factors for household evacuation failure during a natural disaster.

This study characterized risk factors for household evacuation failure. A random digit dial telephone survey was conducted of 397 households in Yuba County, California, in July 1997, 6 months after residents had been under evacuation notice due to flooding. Case households failed to evacuate, whereas control households evacuated. The cumulative incidence of household evacuation failure was 19.4%. Fewer households with children (25.8%) failed to evacuate than households without children (45.9%, p < 0.01). More households with pets (20.9%) than households without pets failed to evacuate (16.3%, p = 0.11). With multivariate logistic regression, the risk of household evacuation failure was lower in households with children (odds ratio = 0.4, 95% confidence interval: 0.2, 0.8) compared with households without children. The risk of household evacuation failure increased in pet-owning households without children (odds ratio = 1.3, 95% confidence interval: 1.1, 1.5) compared with pet-owning households with children; the more pets a household owned, the higher the risk of household evacuation failure was. Impediments to pet evacuation, including owning multiple pets, owning outdoor dogs, or not having a cat carrier, explained why many households that owned pets failed to evacuate. Predisaster planning should place a high priority on facilitating pet evacuation through predisaster education of pet owners and emergency management personnel.

Cisplatin versus cisplatin combined with piroxicam in a canine model of human invasive urinary bladder cancer.

PURPOSE: More than 12,000 people are expected to die from invasive transitional cell carcinoma (TCC) of the urinary bladder each year in the United States, indicating that more effective therapy is needed. Drugs inhibiting cyclooxygenase (cox) have recently been found to have chemopreventive and antitumor activity and may potentiate the effects of chemotherapy. The purpose of this study was to determine whether cisplatin combined with the cox-inhibitor piroxicam would induce remission more frequently than cisplatin alone in a relevant animal model of human invasive TCC. METHODS: Pet dogs with naturally occurring, histopathologically confirmed, measurable TCC of the urinary bladder were randomized to receive cisplatin (60 mg/m2 i.v. every 21 days) or cisplatin (same dosage) combined with piroxicam (0.3 mg/kg orally every 24 h). Complete staging was performed prior to and at 6-week intervals during therapy. RESULTS: After eight dogs had been evaluated in each treatment group, a significant difference in remission rate was noted (Fisher's Exact test, P < 0.004). Tumor responses in the cisplatin/piroxicam group included two complete remissions (CR), four partial remissions (PR), two stable disease (SD), and no progressive disease (PD). Tumor responses to cisplatin alone in eight dogs were no CR, no PR, four SD, and four PD. Six additional dogs were treated with cisplatin/piroxicam, and in total 10 of 14 dogs had remission (two CR, eight PR). Renal toxicity of cisplatin/ piroxicam was frequent and dose limiting. CONCLUSIONS: Cisplatin/piroxicam induced remission more frequently than cisplatin alone in a canine model of human invasive TCC. Strategies to reduce renal toxicity need to be developed prior to evaluation of cisplatin/piroxicam in humans or general use of this treatment in pet dogs.

Coronavirus-associated epizootic catarrhal enteritis in ferrets.

OBJECTIVE: To characterize clinical signs and lesions and identify the etiologic agent associated with epizootic catarrhal enteritis in domestic ferrets. DESIGN: Cross-sectional study. ANIMALS: 119 ferrets with epizootic diarrhea of presumed viral cause and 5 control ferrets. PROCEDURE: Clinical records and biopsy or necropsy specimens of ferrets with presumed epizootic catarrhal enteritis were reviewed. Immunohistochemical staining for coronavirus antigen was performed on paraffin-embedded tissues from approximately 10% of affected ferrets to identify viral antigen and determine its distribution. Transmission electron microscopy was performed on fecal samples and sections of jejunum. Virus isolation studies as well as immunofluorescent tests for other similar viruses were performed. RESULTS: Characteristic microscopic lesions consistent with intestinal coronavirus infection (vacuolar degeneration and necrosis of villus enterocytes; villus atrophy, fusion, and blunting; and lymphocytic enteritis) were consistently detected in affected ferrets. Coronavirus particles were identified in feces and jejunal enterocytes by use of transmission electron microscopy. Immunohistochemical staining of jejunal sections revealed coronavirus antigens. Antigen staining was not detected in healthy ferrets or ferrets with other gastrointestinal tract diseases. Virus isolation was unsuccessful, and other similar viruses were not detected. CONCLUSIONS AND CLINICAL RELEVANCE: Results strongly implicate a coronavirus as the causative agent of epizootic catarrhal enteritis in ferrets. Diagnosis may be made on the basis of a combination of historical, clinical, and microscopic findings.

Life expectancy, antagonistic pleiotropy, and the testis of dogs and men.

BACKGROUND: Prostate cancer and benign prostatic hyperplasia are important age-related prostatic diseases that are under the influence of testicular hormones. However, the disparity between male and female life expectancy within the human population cannot be explained solely by the prevalence of prostatic disease-related mortality. The purpose of this paper is to explore the possibility that the testis exerts a detrimental effect on life span. METHODS: First, we review previously published and unpublished data on the influence of the testis on the life span of dogs and men. Aging in pet dogs and men is then discussed in terms of evolutionary theory, emphasizing the significance of a prolonged postreproductive life span and possible consequences of late-acting deleterious genes in these two species. Finally, we present preliminary data that orchiectomy can reduce DNA damage within the brain of elderly male dogs. RESULTS AND CONCLUSIONS Taken together, these observations raise the intriguing possibility that interventions to antagonize the testis might have much broader therapeutic applications that will extend well beyond the treatment of prostate cancer.

Incidence of and breed-related risk factors for gastric dilatation-volvulus in dogs.

OBJECTIVE: To compare incidence of and breed-related risk factors for gastric dilatation-volvulus (GDV) among 11 dog breeds (Akita, Bloodhound, Collie, Great Dane, Irish Setter, Irish Wolfhound, Newfoundland, Rottweiler, Saint Bernard, Standard Poodle, and Weimaraner). DESIGN: Prospective cohort study. ANIMALS: 1,914 dogs. PROCEDURE: Owners of dogs that did not have a history of GDV were recruited at dog shows, and the dog's length and height and depth and width of the thorax and abdomen were measured. Information concerning the dogs' medical history, genetic background, personality, and diet was obtained from owners, and owners were contacted by mail and telephone at approximately 1-year intervals to determine whether dogs had developed GDV or died. Incidence of GDV based on the number of dog-years at risk was calculated for each breed, and breed-related risk factors were identified. RESULTS AND CLINICAL RELEVANCE: Incidence of GDV for the 7 large (23 to 45 kg [50 to 99 lb]) and 4 giant (> 45 kg [> 99 lb]) breeds was 23 and 26 cases/1,000 dog-years at risk, respectively. Of the 105 dogs that developed GDV, 30 (28.6%) died. Incidence of GDV increased with increasing age. Cumulative incidence of GDV was 5.7% for all breeds. The only breed-specific characteristic significantly associated with a decreased incidence of GDV was an owner-perceived personality trait of happiness.

Non-dietary risk factors for gastric dilatation-volvulus in large and giant breed dogs.

OBJECTIVE: To identify non-dietary risk factors for gastric dilatation-volvulus (GDV) in large breed and giant breed dogs. DESIGN: Prospective cohort study. ANIMALS: 1,637 dogs > or = 6 months old of the following breeds: Akita, Bloodhound, Collie, Great Dane, Irish Setter, Irish Wolfhound, Newfoundland, Rottweiler, Saint Bernard, Standard Poodle, and Weimaraner. PROCEDURE: Owners of dogs that did not have a history of GDV were recruited at dog shows, and the dog's length and height and the depth and width of its thorax and abdomen were measured. Information concerning the dog's medical history, genetic background, personality, and diet was obtained from the owners, and owners were contacted by mail and telephone at approximately 1-year intervals to determine whether dogs had developed GDV or died. Incidence of GDV, calculated on the basis of dog-years at risk for dogs that were or were not exposed to potential risk factors, was used to calculate the relative risk of GDV. RESULTS AND CLINICAL RELEVANCE: Cumulative incidence of GDV during the study was 6% for large breed and giant breed dogs. Factors significantly associated with an increased risk of GDV were increasing age, having a first-degree relative with a history of GDV, having a faster speed of eating, and having a raised feeding bowl. Approximately 20 and 52% of cases of GDV among the large breed and giant breed dogs, respectively, were attributed to having a raised feed bowl.

Burn injury in kitchen workers: a cause for prevention.

Preventable thermal injuries in professional kitchen workers have been identified, and we have introduced a protective garment. Because of the nature of their occupation, kitchen workers are prone to thermal injuries. It has been our experience that the majority of these injuries are scald injuries on the ankles and dorsum of the feet. We propose that a protective garment, such as a waterproof shoe and garter, could reduce the incidence of these injuries.

Naturally-occurring canine transitional cell carcinoma of the urinary bladder A relevant model of human invasive bladder cancer.

Invasive bladder cancer results in over 10,000 deaths yearly in the United States alone. More effective therapy for invasive bladder cancer is clearly needed. As new cellular and molecular targets for therapy are identified, relevant animal models are needed to test new therapeutic strategies aimed at these targets prior to human clinical trials. The purpose of this review is to characterize spontaneous invasive transitional cell carcinoma of the urinary bladder (TCC) in dogs, to summarize the similarities and differences between canine and human invasive TCC, and to describe how canine TCC could serve as a relevant model of human invasive bladder cancer. Information was summarized from 102 dogs with TCC evaluated and treated at the Purdue University Veterinary Teaching Hospital, from a review of the Veterinary Medical Data Base, and from reports in the literature. Canine TCC was found to be very similar to human invasive bladder cancer in histopathologic characteristics, molecular features, biological behavior including metastasis, response to medical therapy, and prognosis. Differences between canine and human TCC were few, but included gender predilection with a male:female ratio of 2.8:1 in humans versus a male:female ratio of 0.5:1 in dogs. The location of the TCC within the bladder also differed: Most canine TCC was trigonal in location, whereas more than 50% of human TCC was in the lateral and posterior walls of the bladder. Considering the great similarity between invasive bladder cancer in humans and dogs, spontaneous canine TCC can be considered a relevant animal model of human invasive bladder cancer.

Immune response of neonatal specific pathogen-free cats to experimental infection with Bartonella henselae.

The purpose of this study was to determine whether neonatal cats develop and maintain a persistent bacteremia for longer than do adult cats with a normal mature immune system, and whether neonatal cats are susceptible to infection with Bartonella henselae by oral inoculation. Neonatal specific pathogen-free (SPF) cats were inoculated with B. henselae intradermally (n = 4) or orally (n = 5) or with 0.9% NaCl (n = 2). Blood was collected periodically through 16 weeks post-inoculation (PI) for serology, bacteriology and complete blood count. Cats inoculated orally or intradermally at 3-5 days of age were bacteremic through 12-16 weeks PI, similar to what is documented for adult cats inoculated intradermally or intravenously. One cat inoculated at age 2 weeks was bacteremic through 10 weeks PI; the other was not bacteremic. Intradermally inoculated neonatal cats produced serum IgG antibodies to B. henselae but orally inoculated neonatal cats did not. Infected cats with and without serum IgG antibodies to B. henselae became blood-culture negative simultaneously, suggesting that IgG is not required to clear bacteremia.

Prevalence of gastric ulcers in show horses.

OBJECTIVE: To determine prevalence and risk factors for gastric ulcers in show horses. DESIGN: Field survey. ANIMALS: 50 horses in active training that had been transported to at least 1 event in the 30 days prior to endoscopy. PROCEDURE: Interview of owner, physical examination, serum biochemical analysis, CBC, and gastric endoscopy were performed. RESULTS: Gastric ulceration was detected in 58% of the horses. Horses with a nervous disposition were more likely to have ulceration than quiet or behaviorally normal horses. Horses with gastric ulceration had significantly lower RBC counts and hemoglobin concentrations than those without ulceration. CONCLUSIONS AND CLINICAL RELEVANCE: Show horses have a high prevalence of gastric ulceration. Lower RBC counts and hemoglobin concentrations may be the result of chronic gastric ulceration.

Nematode intestinal parasites of children in rural Guinea, Africa: prevalence and relationship to geophagia.

BACKGROUND: Intestinal parasitism is common among children in developing countries, but the risk factors for infection are not well characterized. METHODS: A stool examination was performed on 286 randomly selected children aged 1-18 years from three rural villages in Guinea, Africa. Information collected by questionnaire was used to examine the relationship between geophagia and infection with intestinal nematodes acquired by ingestion versus skin penetration. RESULTS: Fifty-three per cent of children were infected by at least one type of soil-transmitted nematode. Geophagia was reported by parents to occur in 57%, 53%, and 43%, of children ages 1-5, 6-10, and 11-18 years, respectively. The pattern of geophagia by age and gender of the children more closely resembled the infection pattern for the two orally acquired and soil-transmitted nematodes (Ascaris lumbricoides, Trichuris trichiura) than it did the infection pattern for the two soil-transmitted nematodes that infect by skin penetration (hookworm, Strongyloides stercoralis). CONCLUSIONS: These findings demonstrate that geophagia is an important risk factor for orally acquired nematode infections in African children. Education regarding geophagia prevention should be an integral component of any soil-transmitted parasite control programme.

PIP: Intestinal parasites are routinely found among children in developing countries, but the risk factors of such infection are poorly characterized. The stools of 286 randomly selected children aged 1-18 years from 3 rural villages in Guinea were examined. Data collected via questionnaire were then analyzed to assess the relationship between geophagia, the regular ingestion of soil, and infection with intestinal nematodes acquired through ingestion rather than through skin penetration. 53% of children were infected with at least 1 type of soil-transmitted nematode, and geophagia was reported by parents to occur in 57%, 53%, and 43% of children aged 1-5, 6-10, and 11-18 years, respectively. The pattern of geophagia by age and gender of the children more closely resembled the infection pattern for the 2 orally acquired and soil-transmitted nematodes Ascaris lumbricoides and Trichuris trichiura than it did the infection pattern for the 2 soil-transmitted nematodes which infect by penetrating the skin, hookworm and Strongyloides stercoralis. Geophagia is therefore an important risk factor for orally acquired nematode infections among African children, and education on geophagia prevention should be an integral component of all soil-transmitted parasite control programs.

Weighing the risks and benefits of vaccination.

The following summarizes this author's current thoughts regarding veterinary vaccines and their safety: 1. Every licensed animal vaccine is probably effective, but also produces some adverse effects. 2. Prelicensing studies of vaccines are not specifically designed to detect adverse vaccine reactions. 3. An improved system of national postmarketing surveillance is required to identify most adverse vaccine reactions that occur at low and moderate frequency. 4. Even a good postmarketing surveillance system is unlikely, however, to detect delayed adverse vaccine reactions, and the longer the delay the less likely they will be associated with vaccination. 5. Analytic epidemiologic (field) studies are the best way to link vaccination with delayed adverse reactions, but these are often hindered by incomplete vaccination histories in medical records in veterinary practice and by a lack of veterinarians in industry trained in epidemiologic methods. 6. Each licensed veterinary vaccine should be subjected to a quantitative risk assessment, and these should be updated on a regular basis as new information becomes available. 7. Risk assessment should be used to identify gaps in information regarding the safety and efficacy of vaccines, and appropriate epidemiologic studies conducted to fill these gaps that contribute to the uncertainty in risk estimates. 8. Risk assessment is an analytical process that is firmly based on scientific considerations, but it also requires judgments to be made when the available information is incomplete. These judgments inevitably draw on both scientific and policy considerations. 9. Representatives from industry, government, veterinary medicine, and the animal-owning public should be involved in risk management, that is, deciding between policy options. The controversy regarding vaccine risks is intensifying to the point that some animal owners have stopped vaccinating their animals. They offer as justification the belief that current vaccines are "just too dangerous." Some owners report that since they completely stopped vaccinating their animals, they have been healthy. What they fail to realize is that a high percentage of animal owners are responsible and do vaccinate their animals, thus providing "herd immunity" protection to the unvaccinated animals whom they contact. The solution to the vaccine controversy is not to abandon vaccination as an effective means of disease prevention and control, but rather to encourage vaccine research to answer important questions regarding safety and to identify the biological basis for adverse reactions. Key questions to be answered include these: What components of vaccines are responsible for adverse reactions? What is the genetic basis for susceptibility to adverse health effects in animals? How can susceptible individuals be identified? Do multivalent vaccines cause a higher rate of adverse reactions than monovalent vaccines? Is administration of multiple doses of monovalent vaccines really any safer than administering a single multivalent vaccine? These and other vaccine-related questions deserve our attention as veterinarians so we can fulfill our veterinary oath to relieve animal suffering and "above all else, do no harm."