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  • Author or Editor: Benjamin J. Weigler x
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Summary

Hantaviruses have emerged as agents of significant morbidity and mortality in human beings. These pathogens are maintained in nature as not clinically apparent, persistent infections in rodent reservoirs, varying with each virus, and are shed via rodent feces, urine, and salivary excretions. Human exposure to hantaviruses principally occurs through the respiratory tract route and is focal and discontinuous, paralleling the distribution of virus in reservoir species and the likelihood of human-rodent interactions. Prior to 1993, hantaviruses were established etiologic agents of human febrile nephropathies and hematologic abnormalities on several continents, exclusive of North America. An episode of severe respiratory tract illness developed in association with a group of novel hantaviruses in the United States during 1993-1994, resulting in at least 98 confirmed cases of disease from 21 states and 51 deaths. Current evidence suggests that hantaviruses of zoonotic potential have long existed across widespread areas of the United States but have gone un-recognized.

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

Objective

To determine whether feline herpesvirus 1 (FHV-1) DNA is in the corneas of clinically normal cats and cats with eosinophilic keratitis or corneal sequestration.

Sample Population

Corneal biopsy specimens obtained from cats referred for treatment of corneal sequestration or eosinophilic keratitis.

Procedure

Corneal scraping or keratectomy specimens collected from clinically normal cats, cats with eosinophilic keratitis, and cats with corneal sequestration were evaluated for FHV-1 DNA by use of polymerase chain reaction (PCR). DNA was extracted from the tissue, and 1 μg was assayed for FHV-1 by use of a single-round (40 cycles) PCR assay with primers directed at a 322-bp region of the thymidine kinase gene. Polymerase chain reaction positivity for clinically normal and affected cats of various breeds was compared by χ2 analysis at α = 0.05.

Results

The FHV-1 DNA was detected in 5.9% (1/17) of corneas from clinically normal cats, in 55.1% (86/156) of corneal sequestra, and in 76.3% (45/59) of scraping specimens from cats with eosinophilic keratitis. Prevalence was significantly (P < 0.001) greater for cats with corneal sequestration or eosinophilic keratitis than for clinically normal cats. For cats with corneal sequestration, prevalence of FHV-1 DNA was significantly lower in Persian and Himalayan, compared with domestic shorthair and longhair breeds.

Conclusion

Data strongly imply involvement of FHV-1 in the pathogenesis of eosinophilic keratitis and corneal sequestration. In Persian and Himalayan breeds, however, other nonviral factors also appear to be involved.

Clinical Relevance

Feline herpesvirus 1 must be considered when treating cats with corneal sequestration or eosinophilic keratitis. (Am J Vet Res 1998;59:856–858)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To determine whether orally administered valacyclovir can be used safely and effectively to treat cats with primary, feline herpesvirus 1 (FHV-1) infection.

Animals

14 specific-pathogen-free adult cats.

Procedure

Cats were infected with FHV-1 strain 87-727 (300 μl, 107 plaque-forming units/ml) by ocular and nasal inoculations, and were treated every 6 hours with dextrose (controls) or valacyclovir (60 mg/kg of body weight, PO). Virus shedding from both eyes and the oropharynx was monitored every 2 days by virus isolation, and subjective clinical scores were assigned daily for ocular and nasal discharge and conjunctival hyperemia. Urinalysis, CBC, and serum biochemical analysis were done prior to inoculation, and on days 2, 5, 7, 9, and 12 of infection. Differences in CBC and serum biochemical indices between groups were compared, as were differences between preinfection values and maximal postinfection values, rectal temperature, and scores for disease severity.

Results

All cats developed acute conjunctivitis and rhinitis typical of FHV-1 infection. Beginning between days 6 and 9, valacyclovir-treated cats became noticeably more lethargic and dehydrated than did cats of the control group. Total WBC and neutrophil counts were significantly lower in cats of the valacyclovir group. The experiment was terminated on day 12 for humane reasons. Histologic changes attributable to FHV-1 infection were similar in all cats. Additional histologic abnormalities seen only in the valacyclovir-treated cats were coagulative necrosis of the renal tubular epithelium, centrilobular atrophy and hepatic necrosis, and severe bone marrow depression.

Conclusions

Cats appear to be uniquely sensitive to the toxic effects of valacyclovir, and even high doses appear not to suppress FHV-1 replication in acutely infected cats.

Clinical Relevance

Use of valacyclovir is of questionable value in cats with acute FHV-1 infection and, at high doses, the drug may be toxic. (Am J Vet Res 1997;58:1141–1144)

Free access
in American Journal of Veterinary Research

Abstract

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.

Full access
in Journal of the American Veterinary Medical Association

Summary

Data on costs associated with episodes of disease and disease prevention, including expenditures for veterinary services, were collected from 57 California beef cow-calf herds during 1988-1989 as part of the National Animal Health Monitoring System. Mean cost associated with episodes of disease was $33.90/cow-year, with $0.78 and $1.37/cow-year being spent for veterinary services and drugs, respectively. The highest costs for veterinary services related to episodes of disease were for dystocia, lameness, and ocular carcinoma. For disease prevention, mean expenditures for veterinary services were $1.67/cow-year, nearly all of which was spent on prevention of reproductive tract conditions. Preventive expenditures for veterinary services related to female infertility (pregnancy examination), vaccination against brucellosis and male infertility (breeding soundness examination) were $0.72, $0.39, and $0.22/cow-year, respectively. Many costs associated with episodes of disease and disease prevention were similar to those reported from Colorado National Animal Health Monitoring System beef herds.

Free access
in Journal of the American Veterinary Medical Association

Summary

Twenty-nine California dairy herds were studied over a 12-month period from 1988 to 1989 as part of the National Animal Health Monitoring System. Monthly interviews administered to dairy producers were used to measure the costs of all health-related expenditures and disease incidence in these herds. Of the total $1,523,558 reported, $1,355,467 (89%) was attributed to cost of disease events and $168,091 (11%) to cost of disease prevention. Most (78%) of the cost of disease events was attributable to death and culling losses. Veterinary services accounted for only $54,099 (4%) of total costs, 64% of which was used for disease prevention, compared with 36% for disease treatment. Udder disease was the most costly category of diseases reported at an average of $49.85/head at risk annually, followed by reproductive problems at $38.05. Through the use of sampling strategies less biased than those used in other surveys, the National Animal Health Monitoring System is designed to provide statistically-valid estimates of disease incidence and costs across broad geographic areas, potentially benefiting all those interested in the economics of livestock diseases in the United States.

Free access
in Journal of the American Veterinary Medical Association