PubMed Health⌕ Search

Biomedical subjects

K E Whitwell

Publications and source records attributed to K E Whitwell.

At least 19 recordsLinked to original sources
PubMed2006

Potential role of multiple rectal biopsies in the diagnosis of equine grass sickness.

Two samples were taken postmortem from the rectum of each of 14 horses with grass sickness and 10 control horses, and four sections stained with haematoxylin and eosin were examined. By using as a criterion of grass sickness the presence of three chromatolytic neurons, 10 of the 14 cases were positive and none of the control horses was positive, giving a sensitivity of 71 per cent and a specificity of 100 per cent. No other histological features appeared to be of diagnostic value, and staining for Nissl substance in neurons with cresyl fast violet and methyl green-pyronin did not improve the sensitivity of the test.

Animals↗
PubMed2006

Investigation of equine influenza cases exhibiting neurological disease: coincidence or association?

Equine influenza is usually a transient and self-limiting disease. However, during an outbreak of equine influenza in the UK in 2003 there were reports of unusually severe clinical signs among unvaccinated animals. Two influenza-infected horses developed neurological signs, and one was subjected to euthanasia. Post-mortem examination of the brain revealed viral-type non-suppurative encephalitis, and influenza virus antigen was demonstrated by immunolabelling of sections of nasal mucosa. A syndrome known as influenza-associated encephalopathy has been described in man. Although not proved, the data suggest that similar disease mechanisms may operate in horses, and that equine influenza virus infection can result in encephalitis in the natural host, perhaps due to an aberrant host immune response.

Amino Acid Sequence↗
PubMed2003

A survey of equine abortion, stillbirth and neonatal death in the UK from 1988 to 1997.

REASONS FOR PERFORMING STUDY: A detailed review of laboratory records for equine abortion is fundamental in establishing current disease trends and suggesting problems important for further research. OBJECTIVES: To review the causes of abortion and neonatal death in equine diagnostic submissions to the Animal Health Trust over a 10 year period. METHODS: The diagnoses in 1252 equine fetuses and neonatal foals were reviewed and analysed into categories. RESULTS: Problems associated with the umbilical cord, comprising umbilical cord torsion and the long cord/cervical pole ischaemia disorder, were the most common diagnoses (38.8%: 35.7% umbilical cord torsion and 3.1% long cord/cervical pole ischaemia disorder). Other noninfective causes of abortion or neonatal death included twinning (6.0%), intrapartum stillbirth (13.7%) and placentitis, associated with infection (9.8%). E. coli and Streptococcus zooepidemicus were the most common bacteria isolated. Neonatal infections not associated with placentitis accounted for 3.2% of incidents; and infections with EHV-1 or EHV-4 for 6.5%. CONCLUSIONS: Definitive diagnosis of equine abortion is possible in the majority of cases where the whole fetus and placenta are submitted for examination. POTENTIAL RELEVANCE: Given the high incidence of umbilical cord torsion and related problems as causes of abortion in UK broodmares, more research on factors determining umbilical cord length and risk of torsion is essential.

Abortion, Veterinary↗
PubMed2000

Virulence of the V592 isolate of equid herpesvirus-1 in ponies.

The V592 strain of equid herpesvirus-1 (EHV-1), which was originally isolated from a fetus during an abortion epizootic, has proved to be of low virulence in infection studies. Five Welsh Mountain pony mares and one foal were challenged intranasally or by aerosol with this isolate, and monitored clinically and virologically. All six animals shed virus in nasopharyngeal mucus, and viraemia was recorded from day 7 post-infection (PI). Pathological investigations revealed mild rhinitis and bronchiolitis in the mares, with viral antigen expression in degenerating epithelial cells of the nasal mucosa and bronchioles, and in occasional monocytes in the respiratory tract-associated lymph nodes. Viral antigen expression was not detected in vascular endothelium of the mares, although vasculitis was seen to have affected small numbers of blood vessels in the dorsocaudal lung regions of a mare examined on day 10 PI. In the foal, respiratory lesions of a more localized nature included infection of vascular endothelium and associated vasculitis. The foal also had localized encephalitis affecting the olfactory lobes of the brain, with viral antigen expression in degenerating olfactory neurons and microglia. The data suggest that the relatively low virulence of strain V592 is associated with a lower degree of endotheliotropism than that shown by the highly virulent Ab4 and Army 183 isolates, and that this property is influenced by host immunity.

Animals↗
PubMed1998

Systemic infection by equid herpesvirus-1 in a Grevy's zebra stallion (Equus grevyi) with particular reference to genital pathology.

A severe multi-systemic form of equid herpesvirus-1 infection is described in an adult zebra stallion. There was multifocal necrotizing rhinitis, marked hydrothorax and pulmonary oedema, with viral antigen expression in degenerating epithelial cells, local endothelial cells and intravascular leucocytes of the nasal mucosa and lung. Specific localization of EHV-1 infection was seen in the testes and epididymides, including infection of Leydig cells and germinal epithelium, which would have facilitated venereal shedding of virus in life. The case provided a unique opportunity to study hitherto undescribed aspects of the pathogenesis of naturally occurring EHV-1 infection in the male equine genital tract. Restriction digests of the isolate demonstrated a pattern similar to that of EHV-1 isolates previously recovered from aborted zebra and onager fetuses.

Animals↗
PubMed1996

Respiratory disease in thoroughbred horses in training: the relationships between disease and viruses, bacteria and environment.

A longitudinal study of respiratory disease in racehorses was carried out to assess its relative associations with different infectious agents and to examine any role that the environmental conditions might play. The relationships between coughing, nasal discharge, pyrexia and lower respiratory tract disease were also examined to provide information for improving clinical diagnosis, particularly of disease of the lower respiratory tract. Lower airway disease was closely associated with infection with Streptococcus zooepidemicus. It was also found that equine herpesvirus seroconversions and S pneumoniae infections were independently associated with the development of nasal discharge. Coughing was a specific, but insensitive measure of lower respiratory tract disease (specificity 84 per cent, sensitivity 38 per cent). However, horses that coughed were very likely to have had lower airway disease for more than one month. Horses housed on straw in loose boxes were twice as likely to suffer from lower airway disease as those kept on shredded paper in American barns. The study was not large enough to assess the significance of rarer infections but it did improve the definition of the problem of respiratory disease in racehorses and revealed some of the trends in the associations between viruses, bacteria and the environment in respiratory disease.

Adenoviridae↗
PubMed1994

Pneumocystis carinii pneumonia in thoroughbred foals: identification of a genetically distinct organism by DNA amplification.

Genetically distinct forms of Pneumocystis carinii infect several mammalian hosts. We report the amplification of P. carinii DNA from samples of two infected thoroughbred foal lungs by using primers designed from the sequence of a P. carinii mitochondrial rRNA gene; these primers also prime the amplification of P. carinii DNA from other hosts. The nucleotide sequence of part of the mitochondrial rRNA gene amplified from P. carinii infecting one of the foals was determined and found to be distinct from that of published rat-, rabbit-, ferret-, and human-derived P. carinii sequences.

Animals↗
PubMed1993

Leporine dysautonomia: further evidence that hares suffer from grass sickness.

The recently described dysautonomia of hares has many similarities to equine grass sickness, particularly when the autonomic ganglia of affected hares and horses are compared by light microscopy. This study shows that the ultrastructural findings are also similar, with a loss of ribosomes from the rough endoplasmic reticulum and distension of its cisternae; the Golgi apparatus is not recognisable in affected neurons. Membranous stacks were identified in autonomic neurons of affected hares, a feature not characteristic of equine grass sickness but often found in feline dysautonomia. Staining with wheat germ agglutinin, a lectin recognising Golgi membranes, showed a lack of reactivity in affected neurons again suggesting a lack of a normal Golgi apparatus.

Animals↗
PubMed1993

An immunohistological study of the uterus of mares following experimental infection by equid herpesvirus 1.

Twelve Welsh Mountain pony mares in late gestation were infected intranasally with EHV-1 (AB4 isolate) at dose rates from 10(3) to 10(7.3) TCID50. This resulted in 3 cases of paresis, at Days 9, 10 and 12 after inoculation, and 5 abortions, at Days 6, 9, 18, 19 and 20. Euthanasia was performed between Days 6 and 21, with collection of uterine specimens for histopathology, virus isolation and immunoperoxidase staining from the pregnant horn, non-pregnant horn and body. EHV-1 replication in endometrial vessels was detected as early as Day 6 and was maximal at Days 9-11, when widespread thromboischaemic damage was present. By Days 15-19 in mares remaining pregnant, EHV-1 antigen expression in the endometrium was sparse, despite residual lesions but little associated thrombosis. Endometrial vascular pathology varied considerably in degree and extent, and no consistent predilection sites for replication within the uterus were apparent.

Abortion, Veterinary↗
PubMed1992

An immunoperoxidase method applied to the diagnosis of equine herpesvirus abortion, using conventional and rapid microwave techniques.

An indirect immunoperoxidase (IMP) technique was applied to cryostat and paraffin sections of liver from ten aborted equine foetuses. Equid herpesvirus type 1 (EHV-1) had been isolated from seven of them and EHV-4 from one: the remaining two were virologically negative and were not used as controls. In the eight virus-infected cases the immunostaining revealed foci of cells exhibiting a distinct brown cytoplasmic and inclusion body pigmentation. No specific signal was present in the non-infected controls. The method also was adapted for incubation in a microwave oven, which allowed the total length of the procedure to be reduced to a minimum of 35 mins for cryostat sections, without significant loss of signal.

Abortion, Veterinary↗
PubMed1992

Pathological findings in horses dying during an outbreak of the paralytic form of Equid herpesvirus type 1 (EHV-1) infection.

In 1988 an outbreak of the paralytic form of Equid herpesvirus type 1 (EHV-1) infection occurred on a stud farm and several animals died. This provided an opportunity to perform detailed pathological investigations to gain insights into the pathogenesis of this spontaneous disease. Two paretic mares, three foals, an aborted foetus and its non-paretic dam were examined. The endotheliotropism of the virus was clearly demonstrated by the use of an indirect immunoperoxidase (IP) stain. At autopsy, evidence of viral infection was widespread in the foetus and foals, but limited or absent in the mares, probably reflecting differences in their immune status. Vascular lesions were present in the central nervous system (CNS) of the foals as well as the adults; they resulted in minimal neural lesions in the foals. Severe changes in the upper and lower respiratory tracts were a particular feature in the foals, two of which exhibited extensive vasculitis and thrombosis in the lungs. The IP technique was of great value in locating antigen-containing cells in the CNS of one mare when virus isolation was negative. It also revealed the presence of virus in less well documented sites such as the pancreas, gut, thyroid, uveal tract and the skin of the nares.

Abortion, Veterinary↗
PubMed1992

Abortion of virologically negative foetuses following experimental challenge of pregnant pony mares with equid herpesvirus 1.

From 1988 to 1991, 51 pregnant pony mares were challenged intranasally or by aerosol with an isolate of EHV-1 (AB4) originally recovered from a quadriplegic mare. This resulted in 32 abortions, occurring from 9 to 29 days after infection. In 14 of the early abortions (Days 9-14), EHV-1 was not demonstrated in the foetal tissues by virus isolation or immunostaining despite no other non-viral cause for the abortion being evident. Application of the polymerase chain reaction to foetal tissues from 9 of these cases also proved negative. One of the 14 mares was destroyed immediately after abortion, and post-mortem examination revealed severe and widespread vasculitis, thrombosis and secondary ischaemic damage in the endometrium with replication of EHV-1 in endothelial cells. These findings suggest that EHV-1 abortion can occur due to endometrial damage without the establishment of a foetal infection.

Abortion, Veterinary↗