Risk-based immunization policies and tuberculosis screening practices for animal care and research workers in the United States: survey results and recommendations.

A national survey was conducted to assess immunization practices and tuberculosis screening methods for animal care and research workers in biomedical settings throughout the United States. Veterinarians (n = 953) were surveyed via a web-based mechanism; completed surveys (n = 308) were analyzed. Results showed that occupational health and safety programs were well-developed, enrolling veterinary, husbandry, and research staff at rates exceeding 90% and involving multiple modalities of health assessments and risk communication for vaccine-preventable diseases. Most (72.7%) institutions did not store serum samples from animal research personnel. More than half of the institutions housed nonhuman primates and maintained tuberculosis screening programs, although screening methods varied. Immunization protocols included various recommended or required vaccines that differed depending on job duties, type of institution, and nature of scientific programs. A single case of an identified vaccine-preventable illness in a laboratory worker was noted. Tetanus toxoid was the predominant vaccine administered (91.7%) to animal care and research workers, followed by hepatitis B (54.8%), influenza (39.9%), and rabies (38.3%). For some immunization protocols, an inconsistent rationale for administration was evident. Indications that animal care and research workers are unprotected from work-related etiologic agents did not emerge from this survey; rather, existing guidelines from the Advisory Committee on Immunization Practices and available biologics seem sufficient to address most needs of the laboratory animal research community. Institutions should commit to performance-based standards in parallel with context-specific risk assessment methods to maintain occupational health and safety programs and practices appropriate to their needs.

Transmission probabilities of mouse parvovirus 1 to sentinel mice chronically exposed to serial dilutions of contaminated bedding.

Intermittent serodetection of mouse parvovirus (MPV) infections in animal facilities occurs frequently when soiled bedding sentinel mouse monitoring systems are used. We evaluated induction of seroconversion in naïve single-caged weanling ICR mice (n = 10 per group) maintained on 5-fold serially diluted contaminated bedding obtained from SCID mice persistently shedding MPV1e. Soiled bedding from the infected SCID mice was collected, diluted, and redistributed weekly to cages housing ICR mice to represent chronic exposure to MPV at varying prevalence in a research colony. Sera was collected every other week for 12 wk and evaluated for reactivity to MPV nonstructural and capsid antigens by multiplex fluorescent immunoassay. Mice were euthanized after seroconversion, and DNA extracted from lymph node and spleen was evaluated by quantitative PCR. Cumulative incidence of MPV infection for each of the 7 soiled bedding dilution groups (range, 1:5 to 1:78125 [v/v]) was 100%, 100%, 90%, 20%, 70%, 60%, and 20%, respectively. Most seropositive mice (78%) converted within the first 2 to 3 wk of soiled bedding exposure, correlating to viral exposure when mice were 4 to 7 wk of age. Viral DNA was detected in lymphoid tissues collected from all mice that were seropositive to VP2 capsid antigen, whereas viral DNA was not detected in lymphoid tissue of seronegative mice. These data indicate seroconversion occurs consistently in young mice exposed to high doses of virus equivalent to fecal MPV loads observed in acutely infected mice, whereas seroconversion is inconsistent in mice chronically exposed to lower doses of virus.

Intussusception in canine recipients of hematopoietic cell grafts and surgical correction.

Intussusception is a common complication after canine hematopoietic cell transplantation (HCT). The present study was undertaken to evaluate predisposing factors of intussusception and to test whether intussusception can be managed surgically during the period immediately after HCT. We determined the incidence of intussusception after HCT was performed in 325 canine recipients (autologous, n = 43; allogeneic, n = 282) during the interval from January 2002 to May 2005. Intussusception was diagnosed in 16 of 325 dogs (4.9%). Intussusception was not significantly associated with the dose of irradiation, source of hematopoietic graft, use of immunosuppressive agents, gender, or age at transplant. A group of 9 of the affected dogs underwent small-bowel resection after diagnosis, and 7 were managed without surgical intervention. Despite complicating factors such as gastrointestinal toxicity and low neutrophil and platelet counts induced by the marrow conditioning regimen and the use of immunosuppressive agents, successful surgical management of intussusception was achieved in 6 of 9 dogs, as compared with successful management of 0 of 7 without surgery. Intussusception did not recur after surgical intervention in any dog. Recent HCT and post-transplant immunosuppressive therapy are not absolute contraindications to surgical intervention for intussusception in canine recipients of HCT.

Use of multigeneration-family molecular dog leukocyte antigen typing to select a hematopoietic cell transplant donor for a dog with T-cell lymphoma.

CASE DESCRIPTION: A 7-year-old Golden Retriever was examined because of anorexia, lethargy, vomiting, and gradual weight loss. CLINICAL FINDINGS: Splenomegaly, pancytopenia, high serum calcium concentration, and high alkaline phosphatase activity were detected. Magnetic resonance imaging revealed an enlarged mesenteric lymph node and increased signals from the bone marrow of the ilium and vertebral bodies. Histologic examination and immunophenotyping of biopsy specimens confirmed a stage V (b) T-cell malignant lymphoma. TREATMENT AND OUTCOME: Clinical remission was attained by use of 2 chemotherapy cycles, followed by an allogeneic hematopoietic cell transplant performed at 18 weeks after diagnosis. A donor was identified by molecular dog leukocyte antigen typing methods. The patient was conditioned with 2 fractions of 4 Gy total body irradiation delivered 3 hours apart at 7 cGy/min, followed by an IV infusion of recombinant canine granulocyte colony-stimulating factor mobilized leukapheresis product and postgrafting immunosuppression with cyclosporine. Chimerism analyses revealed full donor engraftment that has been maintained for at least 58 weeks after transplant. Remission has been confirmed by normal results of serum thymidine kinase assays and the absence of peripheral blood clonal T-cell receptor gene rearrangements. CLINICAL RELEVANCE: Systemic chemotherapy induces remissions; however, most dogs succumb to disease recurrence because of multidrug resistance. Outcome of allogeneic hematopoietic cell transplantation in dogs can be excellent because of improved donor-recipient selection by use of molecular dog leukocyte antigen typing, compared with early attempts, and better prevention of graft versus host disease, better supportive care, and substitution of peripheral blood mononuclear cells for bone marrow.

A national survey of laboratory animal workers concerning occupational risks for zoonotic diseases.

In this cross-sectional survey of laboratory animal workers in the United States, 23 of 1367 persons reported 28 cases of infection with zoonotic agents from research animals at their workplace during the past 5 years, with six persons indicating that their infections were medically confirmed. Based on these data, the annualized incidence rate for work-related transmission of zoonotic agents from laboratory animals was 45 cases per 10,000 worker-years at risk (95% confidence interval, 30 to 65 cases), approximating the rate for nonfatal occupational illnesses in the agricultural production-livestock industry and for those employed in the health services during 2002. Logistic regression analysis found various characteristics of persons and their employers that were significantly associated with the likelihood of having been medically evaluated for exposure to a zoonotic agent from laboratory animals. Most (95.595% +/- 1.1%) persons working with laboratory animals or their tissues indicated that they knew whom to talk to at their institution for medical evaluation and care should they be concerned about the possibility of an occupationally acquired zoonotic disease in future. However, occupational illnesses and exposures among laboratory animal workers was underreported, as 10 of the 28 (36%) alleged zoonotic disease cases were not communicated to the employee's supervisor. Lack of concern about the potential significance to their health and the perception of punitive consequences to the employee were some of the reasons cited for underreporting, an issue which must be vigorously addressed in the interests of continuing progress toward zoonotic disease prevention in this field.

Zoonoses of occupational health importance in contemporary laboratory animal research.

In contemporary laboratory animal facilities, workplace exposure to zoonotic pathogens, agents transmitted to humans from vertebrate animals or their tissues, is an occupational hazard. The primary (e.g., macaques, pigs, dogs, rabbits, mice, and rats) and secondary species (e.g., sheep, goats, cats, ferrets, and pigeons) of animals commonly used in biomedical research, as classified by the American College of Laboratory Animal Medicine, are established or potential hosts for a large number of zoonotic agents. Diseases included in this review are principally those wherein a risk to biomedical facility personnel has been documented by published reports of human cases in laboratory animal research settings, or under reasonably similar circumstances. Diseases are listed alphabetically, and each section includes information about clinical disease, transmission, occurrence, and prevention in animal reservoir species and humans. Our goal is to provide a resource for veterinarians, health-care professionals, technical staff, and administrators that will assist in the design and on-going evaluation of institutional occupational health and safety programs.