Optical microchip array biosensor for multiplexed detection of bio-hazardous agents.

An optical waveguide array biosensor suitable for rapid detection of multiple bio-hazardous agents is presented. SpectroSens™ optical microchip sensors contain multiple spatially-separated waveguide channels with integral high-precision Bragg gratings sensitive to changes in refractive-index; selective surface-functionalisation of discrete sensing channels with different antibodies as bio-recognition elements enables selective multi-analyte biological detection. Interactions between target antigens in the test sample and respective surface-immobilised antibodies result in localised changes in refractive-index; the biosensor response manifests as increases in wavelength of light reflected from specific sensing channels. Multiplexed, label-free detection of 8 different biological agents, encompassing bacterial spores, vegetative cells, viruses and proteinaceous toxins has been demonstrated in real-time. Selective detection of Bacillus atrophaeus (BG) spores, Escherichia coli cells, MS2 viruses and ovalbumin (OVA) protein (simulant bio-hazardous agents) was first demonstrated as proof-of-concept; subsequently, detection of Bacillus anthracis (BA) spores (UM23CL2 strain), Franciscella tularensis (FT) cells (live vaccine strain), Vaccinia viruses (heat-killed) and ricin toxin (bio-hazardous agents) was proven. Two optical microchip sensors, each comprising 8 sensing channels were packaged into a single disposable cartridge allowing simultaneous 16-channel data acquisition. The specific antibody deposition sequence used in this study enabled detection of either 4 simulants or 4 bio-hazardous agents using a single consumable. The final device, a culmination of the multidisciplinary convergence of the fields of biology, chemistry, optoelectronics and microfluidics, is man-portable and inherently robust. The performance characteristics of the SpectroSens™ technology platform highlight its potential for exploitation as a 'detect to warn/treat' biodetector in security and defence operations.

Scopulariopsis chartarum systemic mycosis in a dog.

Scopulariopsis chartarum was reported as the agent of a multisystemic infection in a dog. The clinical syndromes in this dog with a fulminating mycotic disease mimicked those observed in dogs infected with canine distemper virus.

Canine hepatozoonosis in Oklahoma.

Recognition of hepatozoonosis in four dogs that lived in Oklahoma their entire lifetimes documents expansion of the previously recognized endemic area of the disease. Salient clinical features are fever, marked neutrophilic leukocytosis, periosteal new bone proliferation, myalgia, weakness, muscle and generalized wasting, and lack of response to treatment. Transient, large-bowel diarrhea may be observed. Each of the four cases had signs compatible with chronic, persistent inflammatory disease that were poorly and ultimately nonresponsive to antimicrobial treatment. Diagnosis was confirmed in one case by recognition of Hepatozoon gamonts in peripheral blood leukocytes. Encysted forms of the organism were present in skeletal muscle and other tissues of each case.

Hepatic disease associated with administration of tetanus antitoxin in eight horses.

Seven horses developed clinical or subclinical hepatitis 48 to 87 days after administration of tetanus antitoxin. One horse had mildly high hepatic enzyme activity 120 days after inoculation with tetanus antitoxin. The first horse developed signs of depression, lethargy, and anorexia. During hospitalization, signs of hepatoencephalopathy were noticed, and laboratory data were consistent with hepatic disease. Another horse that was found dead had gross and histologic lesions compatible with serum hepatitis. Screening of serum gamma-glutamyltransferase (GGT) and aspartate transaminase activities were used to investigate the remaining horses in the herd. High GGT activities (71 to 206 IU/L) were detected in 5 additional herd members. These horses appeared clinically normal, apart from 2 reports of nasal photosensitization and an aborted fetus. In 3 horses, high serum GGT activity persisted over a 44-day testing period. All affected horses had been given tetanus antitoxin within 12 hours of parturition, and a common source of vaccine was identified for 7 horses. Findings in this group of horses indicate that clinical and subclinical serum hepatitis can develop after administration of tetanus antitoxin.

Use of the neodymium:yttrium-aluminum-garnet laser for treatment of squamous cell carcinoma of the nasal planum in a cat.

A mature castrated male domestic shorthair cat was referred for treatment of an excoriated, ulcerated area on the nasal planum. Undifferentiated squamous cell carcinoma was diagnosed. Surgical resection of the nasal planum was not an option, so the lesion was treated 4 times with neodymium:yttrium-aluminum-garnet laser. Laser surgery results in uniform photovaporization of large volumes of tissue. Although treatment with laser does not yield tissue specimens suitable for histologic evaluation, it can result in a cosmetically suitable appearance and can extend the predicted life span. A diagnosis of undifferentiated squamous cell carcinoma has a guarded prognosis: however, the cat of this report survived more than 18 months.

Epizootic of Yersinia pseudotuberculosis in a wildlife park.

An epizootic attributable to Yersinia pseudotuberculosis infection was confirmed in captive ruminants in a wildlife park by microbiologic and histologic findings. An epornitic of Y pseudotuberculosis infection was identified at the same period in a vicinity near the ruminant deaths. Yersinia pseudotuberculosis can infect human beings and cause acute enteritis and mesenteric lymphadenitis. People in contact with infected animals should use extreme caution and use good sanitary precautions to preclude transmission of this agent.

Elevated IgG antibody to Sarcocystis cruzi associated with eosinophilic myositis in cattle.

Blood sera, skeletal muscle, and cardiac muscle from 24 bovine carcasses condemned for eosinophilic myositis by US Department of Agriculture meat inspection veterinarians were compared with similar specimens from 35 random carcasses passed for human consumption. Fluorescence values determined by using a fluorometric immunoassay system were used to measure the specific antibodies to Sarcocystis cruzi. The values were significantly elevated in carcasses condemned for eosinophilic myositis as compared to carcasses passed for human consumption. The elevated fluorescence values appeared to be more than coincidental, suggesting that S. cruzi may be a causative agent of eosinophilic myositis. Microscopic examination of affected muscle revealed lesions typical of eosinophilic myositis. Lesions were characterized by extensive multifocal areas of myofiber hyaline degeneration, necrosis with sarcoplasmic fragmentation, mineralization of occasional myofibers, and atrophy of fibers with varied stages of fibrosis. Inflammatory cell exudates were predominantly eosinophils, with some macrophages and lymphocytes, and extravasated erythrocytes within, and adjacent to, affected myofibers. Affected muscles contained more S. cruzi than unaffected muscle from passed carcasses. However, a distinct cause and effect relationship could not be determined between the parasite and the presence of eosinophilic myositis.

Zinc deficiency in sheep and goats: three field cases.

Zinc deficiency was diagnosed in 2 flocks of sheep and a herd of goats. Alopecia and eating of wool were observed. Skin lesions were hyperkeratosis and parakeratosis. Abnormal hoof growth and a closed stance with arched back and bowed hindlimbs were seen. Anorexia, depression, and foot soreness diminished quickly after zinc supplementation. Skin lesions healed and hair and wool growth resumed. A cause for the deficiency could not be established.

Toxic effects of fermented and unfermented sorghum meal diets naturally contaminated with mycotoxins.

Male weanling rats fed diets containing fermented and unfermented tannin-free sorghum meals naturally contaminated with traces of ochratoxin A, zearalenone, and an unidentified toxic substance developed anorexia. Mean changes in body weight over a 28-day feeding period for rats fed fermented and unfermented sorghum meal and ANCR casein diets of 8% protein were -2.8, +13.8, and +100.5 g, respectively. Rats fed fermented sorghum meal developed alopecia; hematological findings showed a decreased mean corpuscular volume, hypochromic microcytosis, balanced leukopenia, and hypoproteinuria . Histological findings showed testicular hypoplasia of the germinal epithelium and no mature spermatozoa. Necrosis and mineralization in Henle's loop were also observed. No damage was apparent to the liver, cerebellum, cerebrum, spleen, or adrenal glands.

Pseudorabies in a dog.

Pseudorabies was diagnosed in a 5-year-old female crossbred dog by histologic examination and virus isolation. The clinical signs were depression, salivation, head pressing, and emesis. There were no gross pathologic findings. The microscopic findings in the brain stem consisted of mononuclear cell infiltrates in the leptomeninges, subarachnoid space, and neuropil. In addition, there were mononuclear cell perivascular cuffs, focal areas of gliosis, neuronal degeneration, and acidophilic intranuclear inclusions in neurons and astrocytes. Other microscopic findings were edema of lungs and fatty change in the liver. The virus was isolated from the brain and tonsils and identified by fluorescent antibody technique. Pseudorabies virus was isolated from pigs on the farm.