Histopathology in horses involves the microscopic examination of tissue samples to study the manifestations of disease. This field provides insights into the structural and cellular changes that occur in equine tissues as a result of various pathological conditions. Common applications of histopathology in equine medicine include the diagnosis of neoplastic, inflammatory, and degenerative diseases. Techniques such as tissue staining and immunohistochemistry are employed to identify specific cellular components and pathological markers. This page aggregates peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and implications of histopathological investigations in equine health.
Goodale EC, White SD, Outerbridge CA, Everett AD, Affolter VK.Hyperaesthetic leucotrichia (HL) rarely affects horses and causes painful lesions on the dorsum that result in leucotrichia. This may be a variant of erythema multiforme (EM), but there are no studies investigating this condition. Objective: Describe the clinical and histological features of HL and compare them to the histological features of EM. Methods: A retrospective review of medical records from 1985 to 2015 identified 15 horses with HL. Thirteen biopsies of HL and five of EM were evaluated and compared. Results: Arabian horses and their crosses (χ(2) (1) = 8.56, P < 0.01) and A...
Perez-Ecija A, Mendoza FJ, Estepa JC, Bautista MJ, Pérez J.A 2-month-old foal with septic shock and severe respiratory distress was referred to the Veterinary Teaching Hospital. Due to poor prognosis, the foal was euthanized. Histopathology showed lesions suggestive of Rhodococcus equi infection associated with a diffuse interstitial infiltrate of foamy macrophages and syncytial cells presenting large acidophilic intranuclear inclusion bodies, fibrin exudates and hyaline membranes. Bacteriological examination from lung and respiratory exudates confirmed R. equi infection, whilst immunohistochemistry and PCR yielded a positive result for Equid herpesvi...
Pozor MA, Sheppard B, Hinrichs K, Kelleman AA, Macpherson ML, Runcan E, Choi YH, Diaw M, Mathews PM.Placental changes associated with SCNT have been described in several species, but little information is available in this area in the horse. We evaluated the ultrasonographic, gross, and histopathological characteristics of placentas from three successful and five unsuccessful equine SCNT pregnancies, established using cells from a single donor horse. Starting at approximately 6-month gestation, the pregnancies were monitored periodically using transrectal (TR) and transabdominal (TA) ultrasonography (US) to examine the placentas, fetal fluids, and fetuses. Of the five mares that aborted, one...
Henriksen ML, La Croix N, Wilkie DA, Lassaline-Utter M, Brantman KR, Beamer GL, Teixeira LBC, Dubielzig RR.To describe the clinical and histopathologic features of glaucoma associated with Descemet's membrane (DM) detachment in five horses without prior history of intraocular surgery. Methods: Three Appaloosa horses and two Thoroughbreds were included in this study. The affected horses ranged in age from 16 to 27 years and presented with severe diffuse corneal edema. Methods: Five eyes were enucleated due to intraocular hypertension and/or chronic corneal ulceration. The enucleated globes were evaluated by the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). Each globe was routinely ...
Żuraw A, Plog S, Lierz M, Gruber AD.Sarcocystis calchasi has recently been identified as the cause of pigeon protozoal encephalitis, PPE, a lethal brain disease in pigeons and parrots. While only avian species have been identified so far to be susceptible to this pathogen as definitive or intermediate hosts, we speculated whether mammals may be susceptible as well, as in Sarcocystis neurona and other related apicomplexan parasites. Specifically, we hypothesized its involvement in mammalian meningoencephalitis of unknown origin, MUO. A total of 143 archived formalin fixed, paraffin embedded brain samples with MUO from dogs, cats,...
Hopster K, Jacobson B, Hopster-Iversen C, Rohn K, Kästner SBR.Inappropriate mechanical ventilation can lead to ventilator-induced lung injury (VILI). Aim of this study was to evaluate the effects of inhalation anaesthesia and ventilation with and without recruitment (RM) and PEEP titration on alveolar integrity in horses. Twenty-three horses were divided into 4 groups (group OLC ventilated with OLC, group IPPV ventilated with intermittent positive pressure ventilation, group NV non-ventilated, and group C non-anaesthetized control group). After sedation with xylazine and induction with diazepam and ketamine anaesthetized horses were under isoflurane anae...
Junginger J, Geburek F, Khan MA, Müller G, Gruber AD, Hewicker-Trautwein M.Cutaneous mastocytosis is a rare benign disease occurring in domestic animals and humans. In previous reports, dermal findings in foals were accompanied by systemic mast cell infiltrations, whereas lesions in human cutaneous mastocytosis, including urticaria pigmentosa and solitary mastocytoma, are usually restricted to the skin. Objective: To describe a new variant of equine cutaneous maculopapular mastocytosis lacking systemic involvement. Methods: A 2.5-month-old warmblood foal with multiple skin nodules since birth. Methods: Clinical examination (including haematology, fine needle biopsy a...
Jennings JE.A 21-year-old Appaloosa mare was presented with a pigmented cutaneous mass at the base of the right side of the neck. The diagnosis of phaeohyphomycosis due to pigmented fungi, known as Pyrenophora phaeocomes and Drechslera nobleae, was made based on a histopathology report followed by polymerase chain reaction (PCR) and 18S rRNA gene sequencing. The mass was surgically excised with clean margins, which is usually curative. Une jument Appaloosa âgée de 21 ans a été présentée avec une masse cutanée pigmentée à la base du côté droit du cou. Le diagnostic de phæohyphomycose causée p...
Lee KH, Park C, Bang H, Ahn M, Moon C, Kim S, Shin T.The olfactory mucosae of the horse were examined by using histology and lectin histochemistry to characterize the carbohydrate sugar residues therein. Histological findings revealed that olfactory epithelium (OE) consisted of both olfactory marker protein (OMP)- and protein gene product (PGP) 9.5-positive receptor cells, supporting cells and basal cells with intervening secretory ducts from Bowman's glands. Mucus histochemistry showed that Bowman's gland acini contain periodic acid-Schiff (PAS) reagent-positive neutral mucins and alcian blue pH 2.5-positive mucosubstances. Lectin histochemistr...
Díez de Castro E, Zafra R, Acevedo LM, Pérez J, Acosta I, Rivero JL, Aguilera-Tejero E.Equine motor neuron disease (EMND) is a neuromuscular disorder that affects adult horses. Although EMND has been linked to vitamin E deficiency, its etiopathogenesis is poorly understood. Objective: To describe clinical features, laboratory results, and postmortem findings in a series of young horses with motor neuron disease (MND). Methods: A herd of 15 young Andalusian horses with weakness, weight loss, muscle atrophy, and muscle fasciculations related to restricted intake of green forage. Methods: A case series is presented in which horses were subjected to a clinical examination and plasma...
Ibrahim A, Ali MM, Abou-Khalil NS, Ali MF.For the last few years, researchers have been interested in developing a method for chemical sterilization which may be a better alternative to surgical castration. An ideal chemical sterilant would be one that effectively arrests spermatogenesis and androgenesis as well as libido with absence of toxic or other side effects. Calcium chloride in various solutions and concentrations has been tested in many animal species, but few studies have been evaluated it in equines as a chemical sterilant. So, the objective of this study was to evaluate the clinical efficacy of chemical castration with 20%...
Cleaver N, Parikh K, Kazlouskaya V, Elston D.Equine type melanoma can mimic deep penetrating nevus (DPN), making histologic diagnosis challenging. We sought to investigate if the pattern of collagen polarization could be helpful in this setting. A total of 52 specimens were reviewed with polarized microscopy to determine whether refractile collagen was present within melanocytic nests vs. surrounding but not within the nests. Seven of eight (87.5%) equine type melanomas demonstrated refractile collagen within melanocytic nests in part or all of the lesion. In contrast, DPN showed no refractile collagen within the melanocytic nests. Inste...
Dyson S, Murray R, Pinilla MJ.It has been suggested that ultrasonography is unreliable for the detection of hindlimb proximal suspensory desmopathy (PSD) based on comparisons between ultrasonographic and magnetic resonance images. Objective: To compare ultrasonography with gross and histopathological post mortem examination in horses with PSD diagnosed based on ultrasonography and control horses. Methods: Retrospective descriptive study. Methods: Part 1: 19 horses with hindlimb PSD and 10 control horses were humanely destroyed. Twenty control limbs and 37 lame limbs were examined grossly and 40 suspensory ligaments (SLs) w...
Bischofberger AS, Dart CM, Horadagoda N, Perkins NR, Jeffcott LB, Little CB, Dart AJ.To investigate the effect of 66% Manuka honey gel on the concentrations of transforming growth factor (TGF)-β1 and TGF-β3, bacterial counts and histomorphology during healing of contaminated equine distal limb wounds. Methods: In this experimental study of 10 Standardbred horses, five full-thickness skin wounds (2 × 1.5 cm) were created on one metacarpus and six similar wounds were created on the contralateral metacarpus. Wounds were assigned to three groups: non-contaminated control wounds; contaminated control wounds; contaminated wounds treated daily with 1 mL Manuka honey gel to...
Delcambre GH, Liu J, Herrington JM, Vallario K, Long MT.Phenotypic characterization of cellular responses in equine infectious encephalitides has had limited description of both peripheral and resident cell populations in central nervous system (CNS) tissues due to limited species-specific reagents that react with formalin-fixed, paraffin embedded tissue (FFPE). This study identified a set of antibodies for investigating the immunopathology of infectious CNS diseases in horses. Multiple commercially available staining reagents and antibodies derived from antigens of various species for manual immunohistochemistry (IHC) were screened. Several techni...
Liu Q, Ma J, Wang XF, Xiao F, Li LJ, Zhang JE, Lin YZ, Du C, He XJ, Wang X, Zhou JH.The live equine infectious anemia virus (EIAV) vaccine strain EIAVDLV121 was developed by in vitro attenuation of a virulent strain, EIAVLN40, in the 1970s, and it has been demonstrated to induce protective immunity under laboratory and natural EIAV infection conditions. The detailed biological features of this attenuated virus remain to be further investigated. Experimental inoculation with EIAVDLV121 did not result in clinical symptoms even with immunosuppressive treatment in our previous studies. Here, we further investigated whether the replication of the vaccine strain EIAVDLV121 in exper...
Dixon J, Smith K, Perkins J, Sherlock C, Mair T, Weller R.Melanomas are one of the most common neoplasms in the horse and are frequently found in the head region. There is a genetic predisposition in horses with a gray hair coat. Computed tomography (CT) is frequently used in referral practice to evaluate the equine head but there are few reports describing the CT appearance of melanomas in this location. The aim of this retrospective, case series study was to describe characteristics in a group of horses with confirmed disease. Case records from two referral hospitals were reviewed, and 13 horses were identified that had undergone CT of the head, wi...
Pusterla N, Magdesian KG, Mapes SM, Zavodovskaya R, Kass PH.The ante mortem diagnosis of equine multinodular pulmonary fibrosis (EMPF) relies on histopathological results and polymerase chain reaction (PCR)-positive equine herpesvirus (EHV)-5 testing of lung tissue. Polymerase chain reaction detection of EHV-5 in bronchoalveolar lavage fluid (BALF) is commonly used to support a diagnosis of EMPF. However, the diagnostic power of EHV-5 testing on BALF and other biological samples such as blood and nasal secretions has yet to be shown to support a diagnosis of EMPF. Objective: To determine the frequency of detection and the viral loads of EHV-5 by quanti...
Buczkowska J, Kozdrowski R, Nowak M, Sikora M.Endometrial biopsy score is an accepted marker of uterine health and predicted fertility, and it has been suggested that endometrial alternations are correlated with susceptibility to persistent infectious endometritis. The objective of this study was to investigate associations of endometrial biopsy score with: 1) presence of polymorphonuclear cells (PMNs) in the epithelium and stratum compactum in histopathology; 2) presence of PMNs in cytology and 3) presence of infection in microbiology. Methods: The material for examination was collected from 69 mares suspected for subclinical endometriti...
Suske A, Pöschke A, Müller P, Wöber S, Staszyk C.Incomplete cemental filling of the infundibula of equine maxillary cheek teeth (CT) is a common feature. Depending on the extent of the defect, three stages of infundibular decay have been suggested. However, histomorphological criteria to identify non-pathological abnormalities and destructive changes have not been defined. Six hundred and eighty eight CT with no evidence of dental diseases and 55 diseased permanent, fully erupted maxillary CT were evaluated on a macroscopic level by assessing the occlusal surface and horizontal sections, including porphyrin assays to detect residual blood wi...
Klein V, Müller K, Schoon HA, Reilas T, Rivera del Alamo MM, Katila T.Oestrous suppression by intrauterine devices (IUDs) is caused by prolongation of luteal function, but the biological mechanism is unknown. The aim of the study was to investigate mechanisms which could explain the action of IUDs. Thirty mares were age-matched and either inseminated (AI, n = 15) or fitted with an IUD (IUD, n = 15) and subsequently divided into four groups: AI-P, pregnant (n = 8); AI-N, non-pregnant (n = 7); IUD-P, prolonged luteal phase (n = 7); and IUD-N, normal luteal phase (n = 8). The median ages were 5.5 and 7 years in AI-P and IUD-P groups and 14 and 11 years in AI-N and ...
McGorum BC, Pirie RS, Shaw D, Macintyre N, Cox A.Diagnosis of equine grass sickness (EGS) can be challenging. We hypothesised that subgemmal plexus neurons are chromatolytic in EGS. If correct, histopathological examination of gustatory papillae biopsies could aid premortem diagnosis of EGS, and EGS could represent a spontaneous model of subgemmal neuronal chromatolysis to facilitate study of the pathology of structures involved in taste. Objective: To compare subgemmal plexi and gustatory papillae in EGS and control horses. Methods: Observational study. Methods: Conventional histology and immunohistochemistry were used to compare subgemmal ...
Cesarini C, Cotovio M, Ríos J, Armengou L, Jose-Cunilleras E.Disseminated intravascular coagulation (DIC) is frequent in horses with severe gastrointestinal disorders. Postmortem studies have found fibrin microthrombi in tissues of these horses, but studies relating these histopathological findings with antemortem hemostatic data are lacking. Objective: Antemortem classification of coagulopathy is related to the presence and severity of fibrin deposits observed postmortem in horses with severe gastrointestinal disorders. Methods: Antemortem hemostatic profile data and postmortem tissue samples (kidney, lung, liver) from 48 horses with colic. Methods: Ti...
Gomez DE, Valberg SJ, Magdesian KG, Hanna PE, Lofstedt J.This report describes a case of severe rhabdomyolysis in a pregnant mare associated with histopathologic and biochemical features of both selenium deficiency and acquired multiple acyl-CoA dehydrogenase deficiency (MADD) due to seasonal pasture myopathy (SPM). This case highlights the importance of assessing plasma selenium levels in horses with clinical signs of pasture myopathy as this deficiency may be a contributing or exacerbating factor. Déficience multiple acquise de déshydrogénase acyl-CoA et carence en sélénium marquée causant une rhabdomyolyse grave chez un cheval. Ce rapport d...
Bischofberger AS, Tsang AS, Horadagoda N, Dart CM, Perkins NR, Jeffcott LB, Jackson CJ, Dart AJ.To investigate the effect of activated protein C (APC) on second intention healing of distal limb wounds in horses. Methods: In this experimental study of eight Standardbred geldings, six full-thickness skin wounds (2 × 1.5 cm) were created on one metacarpus (biopsy limb) and five similar wounds were created on the contralateral metacarpus (photographed limb). Three wounds on the biopsy limb were treated topically with 190 µg APC on days 1, 3, 6 and 9, while the remaining three wounds were untreated (control). One treated and one control wound were biopsied on days 4, 7 and 11 for hi...
Vyas R, Keller JJ, Honda K, Cooper KD, Gerstenblith MR.Animal-type melanoma is a rare subtype of melanoma with heavily pigmented dermal epithelioid and spindled melanocytes. Its classification as a subtype of melanoma versus a borderline melanocytic tumor is debated. Objective: Our primary objective was to characterize the demographics, clinical presentation, histopathology, management, and outcomes of patients with animal-type melanoma. Methods: We performed a systematic review and meta-analysis of the English-language literature on animal-type melanoma. Results: We identified 190 cases of animal-type melanoma. They occurred equally in men and wo...
Miller SM, Katzwinkel RH.This case report shows that keratomas can occur in both hind feet of equine patients and should be considered as a diagnosis for long-standing, intermittent lameness localised to the hooves. A Thoroughbred racehorse presented with long-standing abscessation of the right hind hoof. Owing to the long-standing nature, the abscess draining tract was surgically explored. A focal mass was found within the solar horn. Histopathology revealed the mass to be a keratoma. A similar mass was removed from the left hind hoof a few months later after similar presenting signs. This case shows that keratomas c...
Vanschandevijl K, Nollet H, Vercauteren G, Ducatelle R, Deprez P.Transcranial magnetic stimulation (TMS) is an electrophysiological technique used to elicit motor evoked potentials (MMEPs) to evaluate the functional integrity of the descending motor fibres in the spinal cord. Successful application of the technique was reported in horses with spinal cord compression. However, limited data are available on the correlation of TMS with histopathological changes. Objective: To determine sensitivity of TMS for assessing the integrity of the spinal cord in horses with compressive lesions of the spinal cord. Methods: Case series. Methods: The study was conducted o...
Valberg SJ, McKenzie EC, Eyrich LV, Shivers J, Barnes NE, Finno CJ.Although exertional rhabdomyolysis (ER) is common in Arabian horses, there are no dedicated studies describing histopathological characteristics of muscle from Arabian horses with ER. Objective: To prospectively identify distinctive histopathological features of muscle from Arabian endurance horses with a history of ER (pro-ER) and to retrospectively determine their prevalence in archived samples from Arabian horses with exertional myopathies (retro-ER). Methods: Prospective and retrospective histopathological description. Methods: Middle gluteal muscle biopsies obtained from Arabian controls ...
Dawson C, Dixon J, Lam R, Priestnall SL, Escanilla N.To describe the differential diagnoses, investigation, and management of a periocular swelling close to the nasolacrimal duct in a horse that was consistent with a nasolacrimal duct dacryops (lacrimal cyst). A 16-year-old gelding, Connemara cross presented with a history of a periocular swelling rostroventral medial to the right eye that had been sampled by the referring veterinary surgeon. A cystic lesion was diagnosed following standing computed tomography. Surgical removal of the cystic lesion was performed, and the tissue was submitted for histopathologic and immunohistochemical examinatio...
Barnett KC, Blunden AS, Dyson SJ, Whitwell KE, Carson D, Murray R.The case histories described each presented with a visual deficit, varying from permanent total blindness with ophthalmoscopic evidence of optic atrophy to variable and transient visual disturbances, including occasional blindness, but with absence of ophthalmoscopic or any other ocular abnormality. Methods: Three horses of widely different age and type, but all with an original history of upper respiratory tract infection. Methods: All three cases were examined by a specialist veterinary ophthalmologist. In addition, magnetic resonance imaging (MRI) and, where possible, postmortem and histopa...
Sponseller BA, Sponseller BT, Alcott CJ, Kline K, Hostetter J, Reinertson EL, Fales-Williams A.Syringomyelia and hydromyelia are cavitary lesions of the spinal cord that may be acquired or congenital. These lesions are not frequently reported in large animal species. The presenting complaints, clinical, gross pathological, and histopathologic findings of 2 cases of syringomyelia and 1 case of hydromyelia in horses are described. La syringomyélie et l’hydromyélie sont des lésions cavitaires de la colonne vertébrale qui peuvent être acquises ou congénitales. Ces lésions ne sont pas fréquemment signalées chez les espèces de grands animaux. Les plaintes de présentation et les ...
Abood DA, Dawood MS, Mohammed LE, Karim AJ.Certain advantages of donkeys are still not listed as for other equine species. Moreover, donkeys lack comprehensive scientific studies. The present study examines the histological architecture and histochemical characteristics of the esophagus in the Iraqi local breed donkey (). Unassigned: Eight esophagus samples were collected from a local breed donkey. Tissue specimens (~1 cm) were collected from the cervical, thoracic, and abdominal regions of the esophagus and processed via routine histological technique. The tissue sections were stained with hematoxylin and eosin, Massons Trichrome, and...
Beech J.This article discusses the history and signalment, clinical signs, differential diagnosis, pathology, etiology and pathogenesis, and treatment and prevention of equine degenerative myeloencephalopathy.
Devi CN, Borthakur SK, Patra G, Singh NS, Tolenkhomba TC, Ravindran R, Ghosh S.Information pertaining to parasitic fauna and parasitic diseases in Manipuri ponies in India is not available. Moreover, no systematic studies have been undertaken on cutaneous habronemosis in Manipuri ponies which is a common skin problem of Manipuri ponies as reported by pony owners. Keeping in the view of the importance of parasitic infections in veterinary health coverage particularly in Manipuri ponies, the present study was planned. A survey of natural cases of cutaneous habronemosis followed by molecular confirmation of species involved and treatments were done. Out of 200 ponies examin...
Perkins JD, Bowen IM, Else RW, Marr CM, Mayhew IG.The parasympathetic terminal cardiac ganglia were examined in three normal horses and in five horses with grass sickness. Histopathological changes, consistent with those observed in other ganglia of horses with grass sickness, were identified in the terminal cardiac ganglia of the affected horses. A functional analysis of cardiac autonomic control by time domain analysis (TDA) of heart rate variability was applied to eight horses with grass sickness, and double-paired to 16 normal horses on the basis of their age, sex and breed, and the time of day at which the electrocardiographs were obtain...
Fogarty U.The bronchoalveolar lavage (BAL) technique described produced no detectable gross or histopathological lesions. Airway fluid accumulation was observed for up to 4 h post lavage. There was good qualitative correlation between BAL cytopathological and diffuse pulmonary pathological changes. The technique provided an accurate assessment of the presence and extent of exercise induced pulmonary haemorrhage.
Allison N, Gillis JP.Enteric pythiosis was diagnosed in a 2-year-old Quarter Horse gelding. The horse had signs of colic, which appeared to be alleviated by administration of mineral oil and analgesics, but only temporarily. Intestinal distention developed after initial examination. At surgery, a thick stenotic area was observed in the middle portion of the jejunum. The thick intestine and associated mesentery contained multiple firm nodules of gritty caseous material. Histopathologic findings included sclerosing eosinophilic granulomatous enteritis and peritonitis. Although the lesion resembled a response to migr...
Pospischil A, Lieb A, Corboz L.In Switzerland during the foaling season 1988 and 1989 the cause of abortion in 60 foals was investigated. Special attention was paid to infections with equine herpesvirus 1 (EHV 1). Diagnosis were based on post-mortem, histopathological, bacteriological and immunofluorescence investigation. The results confirm data from other countries, that EHV 1 is the most prevalent viral (20%) cause of abortion, followed by various bacterial agents (12%). Other causes were umbilical torsion, twin pregnancy and malformations. In 18% of the cases the investigation of fetuses did not give any results as to t...
Morris CF, Robertson JL, Mann PC, Clark S, Divers TJ.A syndrome characterized clinically by oliguria, progressive severe azotemia, and edema of the abdomen and groin was seen in 2 horses. Treatment with fluids, diuretics, and corticosteroids administered intravenously was ineffective, and the horses were euthanatized. Microscopically, there was severe necrotizing angiopathy with profuse fibrin deposition in renal glomeruli and sinusoids of peripheral lymph nodes. The signs observed in the horses resembled hemolytic-uremic syndrome in human beings.
Reppas GP, McClintock SA, Canfield PJ, Watson GF.Mammary gland neoplasms in horses are uncommon and may initially be confused with mastitis. Masses from the mammary glands of two horses with chronic discharges were examined by cytology and histopathology. Both masses were diagnosed as papillary ductal adenocarcinomas with extensive intraductal and intralobular involvement and only focal infiltration of the adjacent stroma. Complementary immunohistochemical studies were made of both fresh and formalin-fixed tumour tissue, and attempts were made to assess the steroid receptor status of fresh tissue biochemically to assess the possibility of ho...
Rütten M, Lehner A, Pospischil A, Sydler T.Listeria monocytogenes infection, although rare in horses, can lead to septicaemia, gastroenteritis and abortion or stillborn foals. Equine cerebral listeriosis has been reported, but only in newborn animals. This report describes a Freiberger gelding with severe neuronal symptoms of sudden onset. The animal collapsed within 24 h and was humanely killed. Necropsy revealed multiple small brown to reddish foci within the brain stem and pons. Histopathology demonstrated multifocal suppurative meningoencephalitis with microabscesses and occasional intra-lesional, coccoid to rod-shaped, bacteria. T...
Soulé C, Dupouy-Camet J, Georges P, Fontaine JJ, Ancelle T, Delvigne A, Perret C, Collobert C.Seven mares were infected with 20,000 Trichinella spiralis larvae; 2 of them were reinfected 22 wk later with the same amount of larvae. The course of infection in horses was assessed by serology (ELISA), biochemistry (aldolase activity), parasitology and histopathology. In each animal, infection was followed by a significant rise in specific antibody titers culminating at 5-10 wk post-infection (pi) and decreasing thereafter. Reinfection was followed by a slight rise in antibody levels. Aldolase activity increased during the first infection, but was not modified by reinfection. The parasite b...
Pinkerton ME, Bailey KL, Thomas KK, Goetz TE, Valli VE.A 17-year-old Quarterhorse gelding with a clinical diagnosis of protein-losing enteropathy was submitted for necropsy following a 4-5-month duration of weight loss, decreased appetite, and hypoproteinemia. Gross findings included multiple 1-2-cm diameter ulcers on the luminal surfaces of the duodenum and ileum. Histologic examination revealed individual large, round cells infiltrating much of the mucosal epithelium of the duodenum, jejunum, ileum, and colon in addition to multifocal areas of ulceration. Similar round cells infiltrated Brunner's glands and expanded the submucosa beneath the foc...
Darien BJ, Belknap J, Nietfeld J.Two horses with cerebrospinal nematodiasis (Micronema deletrix) had signs similar to those of other neurologic diseases resulting from parasitic (fly larvae, protozoa, or other helminths) migration through the central nervous system (CNS). In one horse (horse 1), a 13-year-old Paso Fino stallion, the cerebrospinal fluid (CSF) was slightly xanthochromic (1+), with a pleocytosis (25 nucleated cells/microliter) and a normal protein level (69 mg/dl). A CSF differential cell count showed 15% neutrophils, 56% lymphocytes, 22% macrophages, 5% eosinophils, and 2% basophils. In the other horse (horse 2...
Atiba A, Ghazy A, Hamad MH.Cutaneous pythiosis in horses is a chronic ulcerative granulomatous disease caused by the oomycete Pythium insidiosum. Objective: The objective of the present study was to evaluate the response of cutaneous pythiosis in horses to surgical excision and topical dimethyl sulphoxide (DMSO). Methods: Thirty horses were presented clinically with pruritus, fistulae discharging serosanguineous fluid, and output kunkers in different body areas (limb, abdomen, neck, and face). The clinical diagnosis was confirmed by isolation of the causative agent and histopathology. All animals were treated by surgica...
Breeze RG, Legreid WW, Bayly WM, Wilson BJ.Perilla ketone was assessed for its usefulness as a model of equine restrictive pulmonary disease. Three ponies were given 18 mg/kg bodyweight synthetic perilla ketone in dimethyl-sulphoxide. Within 24 h of administration, respiratory rate, peak inspiratory and expiratory flow rates and minute volume were increased. By 48 h there was a significant decrease in tidal volume, and blood pH and base excess were also decreased but not outside normal limits. At necropsy there was congestion and oedema of the lungs. Histologically there was diffuse alveolar injury but no evidence of significant obstru...
Dyson S, Murray R, Pinilla MJ.It has been suggested that ultrasonography is unreliable for the detection of hindlimb proximal suspensory desmopathy (PSD) based on comparisons between ultrasonographic and magnetic resonance images. Objective: To compare ultrasonography with gross and histopathological post mortem examination in horses with PSD diagnosed based on ultrasonography and control horses. Methods: Retrospective descriptive study. Methods: Part 1: 19 horses with hindlimb PSD and 10 control horses were humanely destroyed. Twenty control limbs and 37 lame limbs were examined grossly and 40 suspensory ligaments (SLs) w...
Kobayashi A, Sugisaka M, Takehana K, Yamaguchi M, Eerdunchaolu , Iwasa EK, Abe M.This report compares the morphology and the concentrations of glycos-aminoglycans (GAGs) in an injured superficial digital flexor tendon (SDFT) of a horse with those of a normal tendon. An injured 6-year-old male Thoroughbred exhibited heat and swelling around the SDFT of the right forelimb. On histopathological examination, exuberant granulation was observed in the affected tendon, with activated tenocytes, angiogenesis, haemorrhage, and infiltration of small numbers of leucocytes. The collagen fibres were loosely packed and irregularly arranged. The diameter of control collagen fibrils was 2...
Meireles MC, Riet-Correa F, Fischman O, Zambrano AF, Zambrano MS, Ribeiro GA.Equine pythiosis was studied in five animals from two farms located in a swampy region of southern Brazil (Rio Grande do Sul State). Granulomatous lesions exuding necrotic material and containing a central yellow and firm tissue core, the 'kunker', were observed on the top of the nose of one horse, on the abdomen of two horses and on the hind limbs of two other animals. Direct microscopic preparations, histopathological examination of lesion material, and macroscopic and microscopic characteristics of the isolates confirmed the diagnosis of pythiosis. Surgical intervention of the inflammatory ...
Waelchli RO, Winder NC.The distribution of histopathological lesions in the equine endometrium was examined to investigate the representativeness of a single biopsy specimen in terms of the whole endometrium. Five sections from each of 110 uteri obtained from slaughtered mares were evaluated microscopically and classified according to a four-category grading system used for endometrial biopsies. Depending on the extent of agreement between the categories of the homologous sections, the uteri were considered to show either good agreement (81 uteri; 73.6 per cent), moderate agreement (26 uteri; 23.6 per cent) or poor ...
Anderson JA, Alves DA, Cerqueira-Cézar CK, da Silva AF, Murata FHA, Norris JK, Howe DK, Dubey JP.Neosporosis is a common cause of abortion in cattle worldwide but is rare in horses. Here, the first case of histologically, ultrastructurally, immunohistochemically, and molecularly confirmed equine abortion caused by neosporosis is reported. Samples of lung, heart, liver, skeletal muscle, tongue, brain, and the placenta from a female fetus aborted at 280 days of gestation were fixed in formalin and submitted for diagnosis. Histologically, there was disseminated neosporosis with severe lesions in lungs, liver and the heart. Protozoal tachyzoites in all tissues reacted with polyclonal anti-Neo...
Rizk A, Mosbah E, Karrouf G, Abou Alsoud M.Penile and preputial neoplasia in horses occurs infrequently and represents diagnostic and therapeutic challenges. The present study was carried out on a total number of 21 equids (14 stallions and 7 donkeys) suffered from different penile and preputial neoplasia. Diagnosis of neoplasms was based up on history of the case, clinical examination as well as histopathological evaluation. Animals with penile and preputial neoplasms were underwent local excision and partial phallectomy with a slightly modified version of the techniques described by William's. The diagnosed neoplasms were penile and ...
Beck C, Charles JA, Maclean AA.A 16-year-old thoroughbred stallion developed sudden swelling of the left testicle. The stallion had previously been regarded as a unilateral cryptorchid. Ultrasound examination of the left testicle revealed a diffusely heterogeneous parenchyma. The testicle was diffusely hypoechoic with ill defined regions of hyperechogenicity giving the appearance of hypoechoic nodules throughout the testicular parenchyma. No normal testicular tissue was identifiable. An echogenic band, representing a pseudocapsule could be seen surrounding the testicle. Histopathologic diagnosis a seminoma.
Hanson PD, Frisbie DD, Dubielzig RR, Markel MD.A 5-year-old Quarter Horse mare was examined because of a 6-month history of quidding and nasal discharge that contained feed material. Physical examination revealed weight loss and dorsal displacement of the soft palate, caused by a soft tissue mass located at the dorsal aspect of the base of the tongue. Surgical resection of the mass was successfully performed through an oral approach. The histopathologic diagnosis was rhabdomyosarcoma.
Sloet van Oldruitenborgh-Oosterbaan MM, Grinwis GC.Equine sarcoidosis may present as a generalized or localized exfoliative dermatitis and/or as a granulomatous inflammation of multiple organs. Objective: To report the clinical signs, diagnosis, treatment and outcome for 22 horses with histologically confirmed sarcoidosis. Methods: Twenty-two horses of different breeds, between 3 and 17 years of age. Methods: Diagnosis was based on clinical signs and histopathological findings. Results: The following three forms of equine sarcoidosis were identified: generalized (13.6%), partially generalized (18.2%) and localized (68.2%). High-dose systemic c...
Tanimoto T, Yamasaki S, Ohtsuki Y.A well-demarcated solitary splenic mass (20 x 20 x 15 cm in size) containing hemorrhagic and necrotic foci was observed in a 4-year-old Thoroughbred stallion. Histologically, the mass consisted of lymphoma cells of the diffuse large non-cleaved type, with a high mitotic index and scattered macrophages that formed a starry sky pattern. The lymphoma cells revealed diffuse positivity for acid phosphatase and alpha naphthyl butyrate esterase, and were also positive for intracytoplasmic IgM on occasion, and mostly for proliferating cell nuclear antigen. Ultrastructural examination revealed moderate...
Walter I, Helmreich M, Handler J, Aurich C.Chronic degenerative disease of the mare's endometrium is characterised by changes in the uterine glands, including cystic dilation, hyperplasia and periglandular fibrosis. Endometrial biopsies were taken from 23 mares with different grades of endometrial degeneration. Solid structures were identified within the lumina of the uterine glands and shown to be calcified by histochemical staining. Most of them were not homogenous but composed of a mixture of mineral and organic substances. Further examinations of these mineralised structures by immunohistochemical methods revealed the presence of t...
Wooldridge AA, Seahorn TL, Williams J, Taylor HW, Oliver JL, Kim DY, Vicek TJ.A 2-year-old quarter horse gelding presented for evaluation of polyuria and polydipsia. Azotemia was detected on serum chemistry profile. Small, misshapen, hyperechoic kidneys with decreased corticomedullary demarcation, hydronephrosis, and a right nephrolith were noted ultrasonographically. The diagnosis of end-stage kidney disease and dysplasia was made histopathologically using ultrasound-guided biopsy. Two ureteroliths were found in the right ureter via cystoscopy, and a nephrolith was seen in the right kidney at necropsy. Clinical, ultrasonographic, and pathologic features of equine uroli...
Herrera M, Herrera JM, Cantatore S, Aguilar J, Felipe A, Fumuso E.Uterine acute post-breeding inflammation is a physiological tissue response to the entry of exogenous elements, with persistent endometritis being the main pathology responsible for subfertility in the mare (Equus ferus caballus; Linnaeus, 1758). Mares can be classified as susceptible or resistant to endometritis according to their ability to remove intrauterine fluid within 48 hr after experimental inoculation. Endometrial biopsy is a technique that is commonly used to establish the degree of lesions that can affect the fertility of the mare. Endometrial histomorphometry is an objective and ...
