Experimental eosinophilia in domestic fowls and ducks following horse serum stimulation

Multiple intraperitoneal injections of horse serum given to domestic fowls at five different ages resulted in eosinophilia in 55% of adults and in 36% of the younger birds, the highest individual eosinophil level reached being 50% of the differential white cell count. The primary eosinophilic response in fowls was between injections 7 and 36 and there was a secondary response between injections 32 and 72.Horse serum injections produced an eosinophilia in 88% of adult ducks with a maximum individual level of 31% of the differential white cell count. In ducks, primary and secondary eosinophilic responses occurred at injections 13 and 28 respectively.     

Ultrastructural and cytochemical studies in normal Japanese quail (Coturnix coturnix japonica) eosinophils and in those from birds with experimentally induced eosinophilia

Normal eosinophil development in the Japanese quail (Coturnix coturnix japonica) was similar to that described in the fowl and the duck, with granulogenesis occurring in the Golgi apparatus. The characteristic lipid droplets were small in the immature eosinophils, and after staining specifically for lipid, small moieties were also traced to the Golgi apparatus. In mature eosinophils the lipid droplets measured between 1.0 and 1.5 micron in diameter and they were surrounded by profiles of smooth endoplasmic reticulum. Eosinophilia was difficult to induce in quails; injections of either horse serum or bovine serum albumin (BSA)/aluminium hydroxide produced a poor response. In some quails in which eosinophilia was produced, however, eosinophil granules showed many crescentic and vacuolated forms. The lipid droplets in the activated eosinophils were fused in many cells to form large intracellular aggregates of lipid. Quail eosinophils, which hitherto have been regarded as peroxidase-negative, had strong activity in the lipid droplets of cells from stimulated birds. It is postulated that this peroxidase-positive reaction may represent a form of ceroid or lipofuscin pigment resulting from lipid peroxidation. Acid phosphatase and trimetaphosphatase reactions were reduced in many activated cells, with a large proportion of granules being non-reactive. The results of dietary manipulations in quails appear to suggest that in stressful situations the eosinophil metabolism is altered and there is a reduction in the number of lipid droplets in the cell.     

Nuclear lobe index in avian eosinophilia

The nuclear lobe index was calculated for eosinophils from adult fowl, ducks and quail with spontaneous or experimentally induced eosinophilia. Appropriate control birds were also examined. The nuclear lobe index in normal fowl was 1.95 compared with 1.91 in birds with eosinophilia. Although these results (in the fowl) are almost identical, further analysis revealed a distinct 'shift to the right' in those birds with counts greater than 20 per cent eosinophils (P less than 0.01). The normal nuclear lobe index in ducks was 2.68 compared with 2.60 in those with eosinophilia and thus no 'shift' was recognised. The quail, on the other hand, demonstrated a slight 'shift to the left' in which the normal nuclear lobe index was 2.46 compared with 2.20 lobes per cell in eosinophilic quail.     

Elastase-producing microorganisms in horse lungs: their possible role in the pathogenesis of chronic pulmonary disease in the horse

Seventeen out of 21 horses had pulmonary microbial organisms which reached considerable numbers in seven cases. Elastase-producing microorganisms from the environment (Streptomyces species and to a lesser extent Bacillus species) constituted 22 per cent to 99 per cent (mean 79 per cent) of the total growth. There was a considerable number of microorganisms with in vitro-produced elastases which were not or only slightly affected by horse serum. There was no correlation between numbers of organisms and pulmonary histopathological findings thus the significance of these microorganisms in the pathogenesis of alveolar emphysema is unknown. The growth of a strain of Streptomyces collinus/diastatochromogus isolated from the lungs was suppressed by fresh horse serum but not by decomplemented horse serum. Complement activation in response to this organism could contribute to airway inflammation through the production of mediators.     

Fine structural and cytochemical studies of eosinophils from fowls and ducks with eosinophilia

The ultrastructure and cytochemistry of eosinophils from adult fowl and ducks with either spontaneous or experimentally induced eosinophilia were examined. The results showed that a high proportion of the eosinophils in the peripheral blood of eosinophilic birds had ultrastructural features different from those of normal eosinophils. In both species, there was a reduction in cell size. Fowl eosinophil granules showed similar morphological changes to those seen in the quail with many crescentic and vacuolated forms being present. In eosinophilic ducks, the crystalline interna of the specific granules were often fragmented or were either partially or completely lysed. Cytochemically, peroxidase activity in both species was generally unaltered in abnormal eosinophils compared with those from normal birds. This correlates with the findings in man. However, amounts of acid phosphatase and trimetaphosphatase were reduced in many cells, with a large proportion of granules being non-reactive. The latter observation corresponds with that in quail but differs from man, in which stimulated eosinophils have increased enzymatic activity.     

Eosinophils of the horse: Part II: Eosinophils in clinical diseases

Interpretation of eosinophilia in body fluids or tissues is often not straightforward. Eosinophil counts vary among clinically healthy individuals, and considerable overlap can occur between normal and affected animals in conditions such as allergic airway disease. Parasite exposure is a confounding factor when counts are increased, and in cases where very high counts and dramatic clinical signs make another disease process obvious, the underlying pathology may be uncertain and treatment difficult. Eosinophils are a component of the immune response in many diseases of the horse, but their specific role is often unknown and likely multifactorial. In helminth infections, eosinophils are assumed to be part of the normal host response to a pathogen, whereas in multisystemic eosinophilic epitheliotropic disease (MEED), the predominance of eosinophils likely represents a wildly dysregulated response, or an abnormal response altogether. This distinction is still not clear for other diseases. Understanding the pathways involved in recruitment, activation or suppression of eosinophils is required for more accurate diagnostics, effective therapeutics, and successful strategies for prevention of eosinophil associated diseases. Eosinophils of the horse: Part II reviews published observations on the eosinophil in clinical diseases of the horse. The behaviour of eosinophils in three common and relatively well-studied conditions is presented first, including gastrointestinal helminth infections, non-infectious respiratory disease, and insect bite hypersensitivity. The less common eosinophil-associated diseases such as eosinophilic disease confined to the intestine (EDCI) and MEED are considered, followed by a brief summary of the eosinophil in phycomycosis and neoplasia. In conclusion, a panoramic view of the equine eosinophil as presented in Parts I and II is placed in the larger context of current eosinophil research, and areas of study are identified that may improve our understanding of eosinophil biology in equine health and clinical disease.     

Probable occurrence of IgE in the adult domestic fowl (Gallus domesticus) after horse serum stimulation

Radioimmunosorbent techniques using antisera to human immunoglobulin E (IgE) showed the presence of high levels (up to 15,840 U/ml) of IgE in serum and plásma from fowls immunised by repeated intraperitoneal injections of horse serum. These results were confirmed by passive cutaneous anaphylaxis and heat lability tests.     

Relationships among peripheral eosinophilia, eosinophil peroxidase activity, interleukin-5 concentration and faecal nematode egg count during natural, mixed gastrointestinal nematode infection

A longitudinal study of sheep, naturally infected with gastrointestinal helminths, was carried out to quantify the relationships among eosinophilia, eosinophil peroxidase activity, interleukin-5 level and faecal egg counts. Faecal egg counts, peripheral eosinophilia and peroxidase activity per eosinophil were moderately repeatable but interleukin-5 concentrations had a remarkably high repeatability. Animals with higher concentrations of interleukin-5 had greater peripheral eosinophilia and those animals with higher numbers of eosinophils had lower faecal egg counts. These associations were statistically significant but quite weak. Variation in interleukin-5 levels does not appear to be responsible for most of the variation in eosinophil responses in outbred sheep.     

Diseases associated with pronounced eosinophilia: a study of 105 dogs in Sweden

Records of 105 dogs with pronounced eosinophilia (>2.2 X l0⁹ eosinophils/litre) were evaluated in a retrospective study to determine diseases associated with the abnormality in dogs in Sweden. Inflammatory disease in organs with large epithelial surfaces, such as the gut, lungs or skin, was found in 36 per cent of the dogs. A further one-quarter of the 105 cases were placed in the 'miscellaneous' category, which comprised various diseases found at low frequency. The most well defined diagnosis was pulmonary infiltrates with eosinophils in 12 per cent of the dogs. A further 11 per cent had parasitic disease caused by either sarcoptic mange or nasal mite. No atopic dog was found and rottweilers were over-represented in most disease groups. Pronounced eosinophilia, in many cases transient, seems to be associated with a variety of disorders in dogs. In the present study, rottweilers appeared to be more prone to a high eosinophil response than other breeds.     

Bovine serum albumin and cell counts in the diagnosis of subclinical udder infection

Summary

Puncture of the milk cisterns was performed in 120 bacteriologically positive quarters of forty‐seven lactating dairy cows on three farms. This method was used to determine whether the existing infection was an infection of the teat canal or one of the udder. The results were related to the concentration of bovine serum albumin (BSA) and the cell count in the milk. Of the bacteriologically negative quarters, both BSA levels (in 91 per cent of the quarters the BSA concentration was 0.20 mg. per ml. of milk or less) and cell counts (92 per cent contained less than 500,000 cells per ml. of milk) were low. In cases of udder infection with primary pathogenic bacteria there was a marked increase in cell count (90 per cent more than 500,000 cells per ml. of milk), whereas the increase in BSA was rather small (51 per cent still contained 0.20 mg. BSA per ml. of milk or less). While the difference in cell counts of milk from quarters with udder infections and teat canal infections with primary pathogenic bacteria was significant, the difference between the BSA levels of these two groups was not. Therefore, the cell count supplies more reliable information than does the BSA level of the milk. Of all infections, 23 per cent were found to be infections of the teat canal.     

Eosinophilic myeloproliferative disorder in a horse

An eosinophilic myeloproliferative disorder resulted in edema and hemorrhagic diathesis in a 10-month-old Standardbred colt. Laboratory abnormalities included severe thrombocytopenia, anemia, mild hypoproteinemia, and marked eosinophilia. Circulating eosinophils were immature or atypical with variation in granule size, disproportionate nuclear to cytoplasmic maturation, and abnormal nuclear size and shape. Bone marrow aspirate had mainly atypical eosinophil precursors, few erythroid precursors, and no megakaryocytes. A blood transfusion and dexamethasone therapy resulted in some improvement; however, the horse was euthanatized due to poor prognosis. Postmortem examination showed gastrointestinal parasitism; histologically the spleen was infiltrated by atypical eosinophils and there were sites of eosinophilopoiesis. The disease was broadly similar to idiopathic hypereosinophilic syndrome in people, but typical cardiac and neurologic involvement of hypereosinophilic syndrome were absent. Progressive myelophthesis and marked eosinophil atypia suggested malignancy.     

Clinical pathology of experimental stephanuriasis in pigs

SUMMARY Haematology and serum aspartate aminotransferase and alanine aminotransferase activities were studied during the migration phase of Stephanurus dentatus in the livers of experimentally infected pigs. There was no evidence of anaemia but total leucocyte counts were raised and peripheral eosinophilia began 2 to 3 weeks after infection. Peak eosinophilia occurred 6 to 7 weeks after infection and levels were still elevated at 20 weeks. Lymphocyte and neutrophil numbers remained constant. Reinfection did not stimulate a secondary eosinophil response. Only aspartate aminotransferase was temporarily elevated. The gross pathology resulting from the infections is described. Several clinicopathological differences in the response of pigs to invasion of the liver by S. dentatus were noted compared to those produced by Ascaris suum but none are pathognomonic.     

Some characteristics of the antibodies involved in allergic skin reactions of the horse to biting insects

Active skin tests were carried out on a horse with sweet itch using extracts of various biting insects and the resulting reactions compared with those produced when rabbit anti-human IgE was injected intradermally into a normal horse. The horse with sweet itch produced a large reaction to an extract of Culicoides which was similar to those produced by anti-human IgE. Absorption of serum from an allergic horse with anti-human IgE reduced its ability to sensitize skin of a normal horse to challenge with the extract of Culicoides. Passive transfer of allergic horse serum to guinea-pig skin gave significant reactions when challenged after a latent period of 4 h but not after 24 h.     

Selective medium for isolation of Haemophilus somnus from cattle and sheep

Incorporation of vancomycin (5 micrograms/ml), neomycin (5 micrograms/ml), sodium azide (50 micrograms/ml), nystatin (100 iu/ml) and cyclohexamide (100 micrograms/ml) into 5 per cent horse blood agar results in a selective medium for the primary isolation of Haemophilus somnus from cattle and sheep. Addition of thiamine monophosphate (1 microgram/ml) to the medium enhanced growth of this bacterium. Gram-positive bacteria did not grow on the medium and colonies of many Gram-negative bacteria were eliminated or reduced in numbers and size. Colonies of H somnus were larger on the selective medium than on sheep blood agar but retained typical morphology. Recovery of 18 laboratory strains was 73 to 166 per cent (mean 112) on selective medium compared to sheep blood agar. H somnus was isolated from the vagina of a total of 136 (28.6 per cent) of 476 cows surveyed, 79 (16.6 per cent) on sheep blood agar and 129 (27.1 per cent) on selective medium. The selective agents and thiamine were stable indefinitely as a freeze dried mixture while prepared plates were stable for two weeks.     

Inhalation of water during electrical stunning in chickens

Twenty live hens were subjected to electrical stunning using a waterbath containing a solution of technetium99 (99Tc), and 12 hen carcases were injected intratracheally with different doses of the same solution. The respiratory tract was dissected from the carcases and samples were assessed for the presence of radioactivity. Thirty-five per cent of the electrically stunned birds had 99Tc in their tracheas and 15 per cent had 99Tc in the lungs. From the dose response study it was estimated that the birds with radioactivity in their lungs had inhaled between 0.5 and 1 ml of water. In commercial slaughterlines this may be a hazard to meat hygiene.     

Blood eosinophilia in adult bantams naturally infected with Trichostrongylus tenuis

Blood eosinophilia was seen in 36 per cent of 115 adult bantams naturally infested with Trichostrongylus tenuis; the maximum individual count was 56 per cent eosinophils. There were no measurable levels of IgE in the plasma samples and no foci of eosinophils were found in the tissues.     

Idiopathic hypereosinophilic syndrome in 3 Rottweilers

Three Rottweilers with marked peripheral eosinophilia and infiltration of the liver, spleen, lungs, and bone marrow with eosinophils were diagnosed with idiopathic hypereosinophilic syndrome (IHES). Mean serum immunoglobulin E concentrations were markedly high. On cytogenetic analysis, no evidence of karyotypic abnormalities was found in bone marrow aspirates. Despite an extensive search, no underlying cause for the eosinophilia could be identified. In this study, cytogenetic analysis and measurement of serum IgE concentrations were used to differentiate IHES and eosinophilic leukemia.     

Production of monoclonal antibodies specific for native equine IgE and their application to monitor total serum IgE responses in Icelandic and non-Icelandic horses with insect bite dermal hypersensitivity

Immunoglobulin E forms a minor component of serum antibody in mammals. In tissues IgE is bound by FcvarepsilonRI receptors on the surface of mast cells and mediates their release of inflammatory substances in response to antigen. IgE and mast cells have a central role in immunity to parasites and the pathogenesis of allergic diseases in horses and other mammals. This paper describes the production of several novel monoclonal antibodies that detect native equine IgE in immunohistology, ELISA and Western blotting. An antigen capture ELISA to quantify equine IgE in serum has been developed using two of these antibodies. The mean serum IgE concentration of a group of 122 adult horses was 23,523ng/ml with a range of 425-82,610ng/ml. Total serum IgE of healthy horses was compared with that of horses with insect bite dermal hypersensitivity (IBDH) an allergic reaction to the bites of blood feeding insects of Culicoides or Simulium spp. IBDH does not occur in Iceland where Culicoides spp. are absent, but following importation into mainland Europe native Icelandic horses have an exceptionally high incidence of this condition. In the present study Icelandic horses with IBDH had significantly higher total IgE than healthy Icelandic horse controls (P<0.05). By contrast in horses of other breeds the difference in total serum IgE between those affected with IBDH and healthy controls was not statistically significant. Total serum IgE was also monitored in a cohort of Icelandic horses prior to import into Switzerland and for a period of 3 years thereafter. High levels of serum IgE were present in all horses at the start of the study but dropped in the first year after import. Thereafter the total serum IgE remained low in Icelandic horses that remained healthy but rose significantly (P<0.05) in those that developed IBDH. These results support the conclusion that IBDH is a type I hypersensitivity response to insect allergens but indicate that IBDH in Icelandic horses may have a different pathogenesis from the same condition in other breeds.     

Sentinel practice-based survey of the management and health of horses in northern Britain.

Details of the management, feeding, level of activity and routine health care of horses in Scotland and the five northernmost counties in England were recorded through a stratified random sample of horse owners who had responded to a previous survey. Sixty-eight per cent of the horses were kept where their owners resided, and 32 per cent were kept away from the owner's home. More than 99 per cent were turned out to grazing for at least part of the year and 81 per cent were stabled for at least part of the time, most commonly bedded on straw (50 per cent) or shavings (34 per cent). Hay was fed to 87 per cent, sugar beet pulp to 64 per cent and commercially prepared concentrate mixes to 60 per cent of the horses. Hacking was the most popular activity (52 per cent of horses) followed by riding/pony club events (28 per cent) and showing (21 per cent). The majority of the horses were involved in more than one activity. There were an estimated 0.88 veterinary visits per horse per year and 29 per cent of the horses were reported to suffer from at least one permanent or recurrent health disorder. The median annual numbers of administrations of vaccines (influenza and tetanus) and anthelmintics were one and seven respectively per horse, and each horse was shod a median seven times. There were significant differences in the management of horses kept in different types of premises and in areas of different human population density.     

Production and biological properties of M-protein of Streptococcus equi

The production of M-protein antigen of Streptococcus equi was studied during in vitro growth in equine blood and in various media. Of 11 S equi strains studied, seven which had initially possessed 0.04 mg or less M-protein per 10 mg of streptococcal cell extract showed an increase in M-protein content after successive culture in heparinised horse blood. Maximum proliferation occurred in Todd-Hewitt (TH) medium with added 0.2 per cent w/v glucose when compared with TH medium alone or TH medium with 2 per cent w/v sucrose, starch, neopeptone or normal horse serum. The M-protein of these strains did not change after the addition of either neopeptone or normal horse serum to TH medium but declined with the addition of sugars. In experiments involving phagocytosis of S equi by equine polymorphs, the percentage of polymorphs which engulfed cocci was higher with a capsule-deficient strain (69.0 +/- 11.6 per cent) than with five typical encapsulated strains (21.1 +/- 7.0 per cent to 30.9 +/- 13.3 per cent). Phagocytosis of five typical strains was greater after growth in a trypsin-containing medium than in medium devoid of trypsin. Trypsin-grown cells took longer to kill mice than did normal cells. It was concluded that M-protein was one of the factors involved in the virulence of S equi.