Primary blast injuries to the eye: a review of the evidence.

OBJECTIVES: Eye injuries are relatively common following detonations. The majority of these are caused by secondary fragments. Primary blast injury to the eye (from the air-blast alone) has been described historically, but the differentiation of air-blast and fragment aetiologies in the reports is not clear. The aim of this review is to consider the evidence in the literature for true primary blast injury to the eye. METHODS: A literature review using Medline, Pub-med and Web of Knowledge databases. CONCLUSIONS: Overall, there is little conclusive evidence that primary ocular blast injury occurs in survivors of explosions. However, some case reports do surmise its occurrence and it cannot be unequivocally ruled out. If it does occur, it is more likely to be at high overpressures that will produce life-threatening injuries. The development of enhanced blast weapons may result in an increased incidence. At present however, the most severe and damaging threat to the eyes from blast remains the impact of fragments and debris.

Clomipramine and diazepam in the treatment of agoraphobia and social phobia in general practice.

A multi-centre, double-blind trial was carried out in general practice to compare the effectiveness and tolerability of clomipramine and diazepam in patients with agoraphobia or social phobia. Patients were allocated at random to receive one or other of the trial drugs over a period of 12 weeks and dosage was adjusted to need. During the last 4 weeks daily dosage ranged from 25 to 150 mg clomipramine and from 10 to 30 mg diazepam. Analysis of results from 33 patients (15 clomipramine, 18 diazepam) showed that clomipramine was significantly superior to diazepam in improving and maintaining improvement in situational anxiety, interference in lifestyle, accompanied travel distance and total score on an agoraphobia inventory. Tolerability of clomipramine was comparable to that of diazepam.

Postural and neurological deficits in broiler chicks after cervical vaccination with live vaccine.

A disease characterized by paresis and paralysis was seen in 7-9-day-old broiler chicks after vaccination in the neck area at day-of-age with a live virus vaccine containing viruses of Marek's disease, fowl pox, and infectious bursal disease. Affected birds presented with variable signs of ataxia, lateral recumbency, leg paralysis, and twisting or S-shaped flexure of the neck. Gross lesions noted at necropsy included swelling and edema of the subcutaneous tissues and muscles of the neck at the injection site area. A heavy mononuclear inflammatory cell infiltration was seen in the subcutaneous tissues, connective tissues, and muscles of the neck at the injection site. In some cases, the inflammatory process extended along fascial planes to involve the epidural spaces surrounding the spinal cord. Fatty changes with possible demyelination of nerve fibers were noted in some sections of the spinal cord adjacent to the inflammatory lesions. Clusters of poxviruses were found within some inflammatory lesions on transmission electron photomicrographs.

Preliminary characterization of a pleomorphic gram-negative rod associated with avian respiratory disease.

An unidentified, pleomorphic, gram-negative rod (PGNR) bacterium has been isolated from domestic fowl with respiratory disease. The PGNR was isolated in 5% of turkey accessions and 3% of chicken accessions, primarily from the respiratory tract. Preliminary characterization of this organism included reviewing accession records, conducting cultural and biochemical tests, and analyzing cellular fatty acids. The PGNR was also compared with other bacteria capable of inhabiting the avian respiratory system. Biochemical and cellular fatty acid analysis failed to identify the organism, however all 14 isolates were similar.

Pasteurella anatipestifer infections in California turkey flocks: circumstantial evidence of a mosquito vector.

Outbreaks of Pasteurella anatipestifer infections in California turkey flocks were investigated and found to have a seasonal distribution, with a peak incidence in fall, coinciding with peak Culex mosquito populations. An experiment was conducted to test the hypothesis that mosquitoes may serve as vectors for P. anatipestifer infections in turkeys. Four 7-week-old turkey poults were exposed for 7 days to mosquitoes captured from turkey barns during a field outbreak of P. anatipestifer serotype 1 infection. One turkey developed serum antibodies to serotype 1, detectable by enzyme-linked immunosorbant assay, and was resistant to an intravenous inoculation of P. anatipestifer serotype 1 at 4 weeks postexposure. Giemsa-stained blood smears from this bird and from three 7-week-old turkeys inoculated intravenously with P. anatipestifer revealed the presence of rod-shaped bacteria in or on the surface of host erythrocytes. No such rod-shaped bodies were found on erythrocytes of an uninoculated control turkey.

An encephalitic form of listeriosis in broiler chickens.

A disease outbreak characterized by torticollis, incoordination, and depression was seen in a commercial broiler operation in California. Listeria monocytogenes was isolated from brain tissue with some degree of difficulty, and only after culturing directly from the brain stem. No evidence of concurrent disease was found, and the source of the outbreak was undetermined.

Spirochetosis in California game chickens.

An outbreak of spirochetosis occurred in a flock of 75 game chickens in California during fall 1991. Affected birds were weak and anemic. Many had greenish diarrhea. Spirochetes were seen on Giemsa-stained blood smears and in silver-stained tissue sections of kidney, liver, and spleen. Splenomegaly, which is reported to be characteristic of fowl spirochetosis, was not observed in two acutely infected chickens.

Spondylitis in turkeys associated with experimental Pasteurella anatipestifer infection.

Nine previously vaccinated turkeys were inoculated intravenously with Pasteurella anatipestifer, and blood samples were taken periodically to evaluate the potential of chronically infected turkeys to serve as reservoirs of infection for blood-feeding arthropod vectors. Vertebral osteomyelitis (spondylitis), as yet unreported in the literature in association with infection with the organism, was found in the thoracic vertebrae of five out of nine inoculated turkeys, and P. anatipestifer was isolated from the thoracic vertebrae of three of the five. The organism was isolated from the peripheral blood of six turkeys 24 hours postinoculation and from the peripheral blood of one turkey 7 days postinoculation. The organism was also isolated from the heart blood of two birds at necropsy--from one at 21 days and, following an intramuscular injection of dexamethasone, from the other turkey at 38 days postinoculation.

Egg production drops in breeder turkeys associated with western equine encephalitis virus infection.

Egg production drops associated with western equine encephalitis (WEE) virus infection occurred in three turkey breeder flocks in California during summer 1993 and again in one flock the following year. Egg production losses totaled 8.76%, 9.57%, 9.71%, and 10.12% and were accompanied by an increase in small white-shelled and shell-less eggs. The outbreaks coincided with peak WEE virus activity in the state on the basis of statistics compiled by the California Department of Health Services on seroconversion rates in sentinel chicken flocks. Paired serum samples taken 2-3 wk apart showed increased titers to WEE between acute and convalescent sera in turkeys from three affected flocks. Convalescent sera were not available for testing from the fourth flock. WEE virus was isolated from one breeder hen submitted to the diagnostic laboratory during the early stages of the outbreak.

Hexamita meleagridis (Spironucleus meleagridis) infection in chukar partridges associated with high mortality and intracellular trophozoites.

An outbreak of infectious catarrhal enteritis, associated with the flagellated protozoan Spironucleus meleagridis (syn. Hexamita meleagridis), is reported from a commercial flock of chukar partridges in California. The disease affected birds between the ages of 4 and 6 wk and resulted in diarrhea, listlessness, depression, and high mortality. Concurrent infection with other intestinal pathogens, including Cryptosporidia, group E Salmonella, long-segmented filamentous microorganisms (LSFMOs), and Rotavirus-like virus particles, was found in some but not all affected birds. Dermatitis of the face, shanks, and feet, suggestive of B-complex vitamin deficiency, was present in most affected birds as well. Flagellated protozoan parasites could be found in the lumen of the duodenum and jejunum and in the intestinal crypts. In some cases the flagellates were wedged between epithelial cells or were located intracellularly within cells of the mucosal epithelium and the intestinal lamina propria.

An outbreak of erysipelas in 2-day-old poults.

Systemic erysipelas infection was seen in 2-to-4-day-old poults from three separate ranches owned by the same company. The affected poults were all from the same breeder source; poults from other breeder sources were seemingly unaffected. Mortality increased on days 2 and 3, ranging from 2% to 8.5%. Birds submitted were dehydrated and very weak, with one half of the poults submitted having died during transport to the lab. Gross lesions included swollen, congested livers and spleens, as well as hemorrhagic breast muscle in one case. Toes were swollen and reddish-purple in color. The poults had been toe-trimmed during hatchery processing using a commercial microwave. Histologically, periportal inflammation with heterophilic infiltration in the liver was noted. Spleens showed hyalinization of arteries, lymphoid depletion, and necrosis. Toe joints showed purulent synovitis and cellulitis. Gram stains done on impression smears of liver and spleen showed rare to moderate numbers of small gram-positive rods. Erysipelothrix rhusiopathiae was isolated from 18 of 22 livers cultured, five of six toe joints cultured, and from the yolk sac in two birds.

Skeletal myopathy produced with experimental dosing of turkeys with monensin.

Monensin was given via gavage to 5- and 6-week-old broad-breasted white turkeys. The birds were allotted into four groups--three groups given monensin and one group of controls--in two experimental trials. Treated turkeys in Trial 1 received one dose of monensin per day for 4 days at 4.7 mg monensin/kg body weight, 8.8 mg/kg, or 17.6 mg/kg. Treated turkeys in Trial 2 received one dose of monensin per day for 5 days at 1.93 mg/kg, 4.7 mg/kg, or 8.8 mg/kg. Turkeys receiving the lowest dose showed no clinical signs of myopathy. Birds receiving 4.7 mg monensin/kg developed ataxia after the third dose and rear limb paresis and paralysis after the fifth dose. Turkeys receiving 8.8 mg/kg were ataxic after the second dose and paretic or paralyzed after the fourth dose. Turkeys receiving 17.6 mg/kg were ataxic 3 hours after the first dose and paretic or paralyzed 8 hours after the first dose. Histologically, a necrotizing skeletal myopathy was present in the muscles of the rear limbs. A dose-related response was observed in the percentage of myofibers damaged in birds that survived until the end of the trials. Intrafiber edema and vacuolation were observed in histologic sections from myocardium of turkeys from the two highest dose groups.

Enterococcus durans infection in young chickens associated with bacteremia and encephalomalacia.

Two unrelated flocks of chicks experienced elevated mortality from 4 to 10 days of age. Clinical signs in affected birds included a full range of neurological disorders. Livers and spleens were grossly enlarged at necropsy. Enterococcus durans was isolated from multiple organs, including brains. Histologically, there were multifocal coagulative necrosis in the liver, areas of malacia in brain stem, and cerebellar white matter. Inoculation of 1-day-old chicks with a suspension of E. durans resulted in bacteremia but did not produce the lesions observed in field cases.

Infectious coryza in meat chickens in the San Joaquin Valley of California.

Two cases of infectious coryza in meat chickens are reported. The first case involved 6-week-old broiler chickens in which only Haemophilus paragallinarum was isolated. The second case involved 11-week-old roaster chickens in which H. paragallinarum and Mycoplasma synoviae were isolated. Both farms were in close proximity to layer-chicken farms where infectious coryza had been previously diagnosed. In both cases, only certain houses on the farm were affected, and mortality in these houses increased slightly. At processing, the condemnation rates for affected houses were considerably higher than rates for unaffected houses. Condemnations for affected houses were mostly due to airsacculitis. A dissecting fibronopurulent cellulitis was a prominent lesion in the second case. This lesion could lead to confusion with chronic fowl cholera and swollen-head syndrome.

An outbreak of infectious laryngotracheitis in California broilers.

Infectious laryngotracheitis (ILT) was diagnosed as the cause of an outbreak of respiratory disease in broiler chickens in California. The classical form of ILT is characterized by dyspnea, gasping, coughing, and expectoration of bloody exudate. Most of the broilers submitted to the diagnostic laboratory showed a non-classical presentation of ILT, in which mucoid tracheitis and conjunctivitis were the most consistent lesions. Historically, most of the ILT cases diagnosed in our laboratory have consisted of layers with classical signs and lesions. It is not known whether this non classical presentation of ILT in broilers is due to differences in the way broilers respond to ILT infection or to the nature of the ILT virus isolate.

Systemic trichomoniasis in a squab operation.

Systemic trichomoniasis was responsible for severe morbidity and mortality in a commercial squab operation. Squabs of 1 to 3 weeks of age were primarily affected. Extensive caseous necrosis of the liver, heart, lung, and intestinal mesentery was observed grossly. Histologically, extensive heterophilic inflammation surrounded the necrotic areas and was observed perivascularly in areas that were uninvolved grossly. Numerous trichomonads were demonstrated in affected tissues with Bodian's silver stain.

Avian paramyxovirus type 1 infections in racing pigeons in California. I. Clinical signs, pathology, and serology.

An outbreak of diarrhea and neurological disease in California racing pigeons caused by avian paramyxovirus type 1 (PMV-1) is documented. Predominant clinical signs were polydipsia, ataxia, poor balance, torticollis, head tremors, inability to fly, and diarrhea that was unresponsive to therapy. Gross pathologic findings were often unremarkable or non-specific. The predominant histologic lesions were interstitial nephritis, chronic tubular necrosis, lymphoplasmacytic infiltration within the kidney, liver, and pancreas, and focal non-suppurative encephalitis. Pigeons from 20 submissions demonstrated characteristic clinical signs of PMV-1 infection. Pigeons from 17 submissions exhibited typical histopathology. Serologic evidence of PMV-1 infection was present in pigeons from 13 submissions, and PMV-1 was isolated from pigeons received in six submissions. None of these pigeons had been vaccinated against PMV-1.

Ascaridia dissimilis larval migration associated with enteritis and low market weights in meat turkeys.

A meat turkey ranch had a history of producing flocks with low market weights. Live bird samples and environmental samples from the ranch were collected over a period of eight months and analyzed at the California Veterinary Diagnostic Laboratory System-Turlock Branch. The disease condition consistently present was enteritis associated with Ascaridia dissimilis infection in birds from growout houses. After aggressive control measures for A. dissimilis were implemented, subsequent flocks reached expected market weights.

Esophageal trichomoniasis in chickens.

Esophageal trichomoniasis has been rarely reported in chickens. At the California Veterinary Diagnostic Laboratory System-Turlock Branch, this disease was recently diagnosed in two cases submitted from backyard chicken flocks. The esophageal lesions observed were similar to those seen in several other important diseases of chickens. The causative trichomonad organisms were readily demonstrated on wet smears and by histologic studies. In both cases, the investigated flocks were afflicted with several concurrent diseases. California has experienced an increase in the number of small nontraditional chicken production operations. These facilities are sometimes in close proximity to commercial poultry operations and biosecurity barriers occasionally fail. The poor husbandry practices often used in these small flocks make them a potential reservoir for rare diseases such as trichomoniasis and also for disease organisms that are devastating to commercial poultry.

Experimental infection of turkey poults with western equine encephalitis virus.

The pathogenicity of a field isolate of western equine encephalitis (WEE) virus, which was recovered from a breeder hen during investigations of egg production drops in California turkey flocks, was tested in 2-wk-old turkey poults. No symptoms or mortality were observed in poults inoculated intramuscularly with 4.2 log10 50% embryo lethal doses of virus; however, the infection did result in mild to moderate lymphoid necrosis in the bursa of Fabricius and thymus glands beginning on the first day postinoculation. In addition, WEE virus could be isolated from the blood of infected poults for up to 3 days postinoculation.