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Beckwith-Cohen B, Petersen-Jones SM. Manifestations of systemic disease in the retina and fundus of cats and dogs. Front Vet Sci 2024; 11:1337062. [PMID: 38444779 PMCID: PMC10912207 DOI: 10.3389/fvets.2024.1337062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 01/15/2024] [Indexed: 03/07/2024] Open
Abstract
The fundus is unique in that it is the only part of the body that allows for a noninvasive and uninterrupted view of vasculature and nervous tissue. Utilization of this can be a powerful tool in uncovering salient incidental findings which point to underlying systemic diseases, and for monitoring response to therapy. Retinal venules and arterioles allow the clinician to assess changes in vascular color, diameter, outline, and tortuosity. The retina and optic nerve may exhibit changes associated with increased or decreased thickness, inflammatory infiltrates, hemorrhages, and detachments. While some retinal manifestations of systemic disease may be nonspecific, others are pathognomonic, and may be the presenting sign for a systemic illness. The examination of the fundus is an essential part of the comprehensive physical examination. Systemic diseases which may present with retinal abnormalities include a variety of disease classifications, as represented by the DAMNIT-V acronym, for Degenerative/Developmental, Anomalous, Metabolic, Neoplastic, Nutritional, Inflammatory (Infectious/Immune-mediated/ischemic), Toxic, Traumatic and Vascular. This review details systemic illnesses or syndromes that have been reported to manifest in the fundus of companion animals and discusses key aspects in differentiating their underlying cause. Normal variations in retinal anatomy and morphology are also considered.
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Affiliation(s)
- Billie Beckwith-Cohen
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
| | - Simon M. Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
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Olofsson KM, van de Velde N, Peletto S, Iulini B, Pratley L, Modabberzadeh B, Małek E, Grandi G. First Swedish case of fatal equine parasitic encephalitis by Halicephalobus gingivalis. Acta Vet Scand 2023; 65:56. [PMID: 38102633 PMCID: PMC10722705 DOI: 10.1186/s13028-023-00719-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND Halicephalobus gingivalis is a nematode with zoonotic potential which can cause fatal opportunistic infections in various mammals. The parasite has never been diagnosed in Sweden, in any species, prior to the presented case. CASE PRESENTATION An imported 21-year-old Icelandic mare developed severe neurological signs. The horse was eventually euthanized and submitted for post-mortem examination where severe lesions in the kidneys were noted. Histopathology revealed the presence of H. gingivalis in both kidneys and the brain. Phylogenetic analysis of the parasite determined it to belong to Lineage 1. CONCLUSIONS With the occurrence of H. gingivalis in Sweden, the disease should be added to the list of differential diagnoses in cases with acute onset of neurological disease in both horses and other mammals including humans.
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Affiliation(s)
- Karin Maria Olofsson
- Department of Pathology and Wildlife Diseases, National Veterinary Institute (SVA), Uppsala, Sweden
| | - Norbert van de Velde
- Department of Pathology and Wildlife Diseases, National Veterinary Institute (SVA), Uppsala, Sweden
| | - Simone Peletto
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle D'Aosta, Turin, Italy
| | - Barbara Iulini
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle D'Aosta, Turin, Italy
| | - Laura Pratley
- Evidensia Specialisthästsjukhuset Helsingborg, Helsingborg, Sweden
| | | | - Emilian Małek
- Department of Pathology and Wildlife Diseases, National Veterinary Institute (SVA), Uppsala, Sweden
| | - Giulio Grandi
- Department of Microbiology, National Veterinary Institute (SVA), Uppsala, Sweden.
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
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Borges DGL, de Almeida Borges F, Vieira MC, Pupin RC, de Araújo MA, de Castro Guizelini C, de Lemos RAA. Poisoning of calves reared with cows treated with abamectin. Toxicon 2021; 203:115-116. [PMID: 34662630 DOI: 10.1016/j.toxicon.2021.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/30/2021] [Accepted: 10/12/2021] [Indexed: 10/20/2022]
Abstract
The aim of the present study was to describe an outbreak of poisoning by abamectin in calves less than four months of age whose mothers were treated with a pour-on product containing this ingredient. The diagnosis was based on the history, clinical signs, absence of macroscopic and histopathological findings (characteristic of this type of poisoning) and the detection of abamectin in tissues of the animals submitted to necropsy. Based on this report, the recommendation is the use with caution of pour-on formulations containing abamectin on cows having given birth less than four months earlier.
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Affiliation(s)
- Dyego Gonçalves Lino Borges
- Laboratório de Doenças Parasitárias, Faculdade de Medicina Veterinária e Zootecnia (FAMEZ), Universidade Federal de Mato Grosso Do Sul (UFMS), Campo Grande, MS, Brazil.
| | - Fernando de Almeida Borges
- Laboratório de Doenças Parasitárias, Faculdade de Medicina Veterinária e Zootecnia (FAMEZ), Universidade Federal de Mato Grosso Do Sul (UFMS), Campo Grande, MS, Brazil
| | | | - Rayane Chitolina Pupin
- Laboratório de Anatomia Patológica, Faculdade de Medicina Veterinária e Zootecnia (FAMEZ), Universidade Federal de Mato Grosso Do Sul (UFMS), Campo Grande, MS, Brazil
| | - Marcelo Augusto de Araújo
- Hospital Veterinário, Clínica de Grandes Animais, Faculdade de Medicina Veterinária e Zootecnia (FAMEZ), Universidade Federal de Mato Grosso Do Sul (UFMS), Campo Grande, MS, Brazil
| | - Carolina de Castro Guizelini
- Programa de Pós-graduação Em Ciências Veterinárias, Faculdade de Medicina Veterinária e Zootecnia (FAMEZ), Universidade Federal de Mato Grosso Do Sul (UFMS), Campo Grande, MS, Brazil
| | - Ricardo Antônio Amaral de Lemos
- Laboratório de Anatomia Patológica, Faculdade de Medicina Veterinária e Zootecnia (FAMEZ), Universidade Federal de Mato Grosso Do Sul (UFMS), Campo Grande, MS, Brazil
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Guerra JC, McKenzie EC. The use of prolonged administration of low-dose intravenous lipid emulsion to treat ivermectin toxicosis in goats. J Am Vet Med Assoc 2021; 259:914-918. [PMID: 34609187 DOI: 10.2460/javma.259.8.914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CASE DESCRIPTION 2 Nigerian Dwarf goats (a doe [goat 1] and a wether [goat 2]) with coughing and nasal discharge since they were purchased at an auction 6 days prior were empirically treated for suspected pneumonia and intestinal parasitism. An ivermectin dosing error (intended dose, 0.4 mg/kg, PO; administered dose, 10 mg/kg, PO) was retrospectively discovered, and the owner was urged to return the goats for hospitalization and treatment. CLINICAL FINDINGS On admission 19 hours after iatrogenic ivermectin overdose, both goats had tachycardia, tachypnea, and absent menace responses. Goat 1 also had vomited in transit, was lethargic and febrile, had slow pupillary light reflexes, and walked into walls and obstacles. Goat 2 was quiet but responsive, not ataxic or febrile, and had pale mucous membranes and a prolonged capillary refill time. TREATMENT AND OUTCOME Each goat received 20% IV lipid emulsion (2 mL/kg, IV bolus over 15 minutes, followed by 0.008 mL/kg/min, IV) and immediately improved. Activated charcoal was administered by orogastric tube, and 6 hours later, mineral oil was similarly administered. Goat 1 had complete resolution of signs and was discharged by 48 and 72 hours, respectively, after admission. Goat 2 improved but developed progressive respiratory distress after the second orogastric intubation and was euthanized. Necropsy findings were consistent with acute renal tubular necrosis, acute respiratory distress syndrome of unknown cause, ruminal tympany, and mesenteric caseous lymphadenitis. CLINICAL RELEVANCE Results indicated that IV lipid emulsion could be used to successfully treat ivermectin toxicosis in goats. Treatment early in the course of ivermectin toxicosis is advisable to avoid severe clinical signs and secondary complications.
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Madrigal RG, Friedemann MC, Vallone JM, Ruoff CM, Vallone LV, Laughrey T, Rech RR, Coleman MC. Ossifying fibroma as a cause of blindness in a 5‐year‐old Quarter Horse gelding. EQUINE VET EDUC 2020. [DOI: 10.1111/eve.12944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- R. G. Madrigal
- Department of Veterinary Large Animal Clinical Sciences Texas A&M UniversityCollege Station Texas USA
| | - M. C. Friedemann
- Department of Veterinary Pathobiology Texas A&M UniversityCollege Station TexasUSA
| | - J. M. Vallone
- Department of Veterinary Large Animal Clinical Sciences Texas A&M UniversityCollege Station Texas USA
| | - C. M. Ruoff
- Department of Veterinary Large Animal Clinical Sciences Texas A&M UniversityCollege Station Texas USA
| | - L. V. Vallone
- Department of Veterinary Small Animal Clinical Sciences College of Veterinary Medicine and Biomedical Sciences Texas A&M University College StationTexas USA
| | | | - R. R. Rech
- Department of Veterinary Pathobiology Texas A&M UniversityCollege Station TexasUSA
| | - M. C. Coleman
- Department of Veterinary Large Animal Clinical Sciences Texas A&M UniversityCollege Station Texas USA
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Anthelmintic drugs used in equine species. Vet Parasitol 2018; 261:27-52. [PMID: 30253849 DOI: 10.1016/j.vetpar.2018.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/01/2018] [Accepted: 08/06/2018] [Indexed: 01/16/2023]
Abstract
Internal parasites of horses comprise an intractable problem conferring disease, production and performance losses. Parasitism can rarely be controlled in grazing horses by management alone and anthelmintic drugs have formed the basis of therapy and prophylaxis for the last sixty years. The pharmacology of the anthelmintic drugs available dictate their spectrum of activity and degree of efficacy, their optimal routes of administration and characteristics which prevent some routes of administration, their safety tolerance and potential toxicities and as a consequence of their persistence in the body at effective concentrations their use in epidemiological control programmes. Their use has also resulted in the selection of parasites with genetically controlled characteristics which reduce their susceptibility to treatment, characteristics which are often common to whole chemical classes of anthelmintics. Pharmacological properties also confer compatibility in terms of safety and persistence with other anthelmintic drugs and thus the potential of combinations to treat parasites from different phylogenetic groups such as nematodes, cestodes and trematodes and also the potential by agency of their different molecular mechanisms of action to delay the selection of resistant genes. The major groups of anthelmintics now available, the benzimidazoles (BZD), macrocyclic lactones (MLs) and tetrahydropyrimidines are all highly effective against their targeted parasites (primarily nematodes for BZD's and ML's and cestodes for tetrahydropyrimidines) easily administered orally to horses and are well tolerated with wide margins of safety. Nevertheless, some parasitic stages are inherently less susceptible such as hypobiotic stages of the small strongyles (cyathostomins) and for some such as the adult stages of cyathostomins resistance has developed. Furthermore, for some less common parasites such as the liver fluke unlicensed drugs such as the salicylanilide, closantel have been used. A deep understanding of the pharmacology of anthelmintic drugs is essential to their optimal use in equine species.
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Diseases of the Nervous System. Vet Med (Auckl) 2017. [PMCID: PMC7322266 DOI: 10.1016/b978-0-7020-5246-0.00014-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Pollio D, Michau TM, Weaver E, Kuebelbeck KL. Electroretinographic changes after intravenous lipid emulsion therapy in a dog and a foal with ivermectin toxicosis. Vet Ophthalmol 2016; 21:82-87. [PMID: 27440451 DOI: 10.1111/vop.12410] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This case report describes ivermectin-induced blindness in a dog and a foal with normal ophthalmic fundic examinations and attenuated electroretinography (ERG). Subsequent recovery in ERG was noted following intravenous lipid emulsion (ILE) therapy. A dog and a foal were evaluated for ivermectin-induced blindness. Clinical signs included dull mentation, absent pupillary light reflexes (PLRs), and absent menace on presentation. The animals had normal fundoscopic examinations; however, in both cases ERG was consistent with neurosensory retinal dysfunction. Following ILE therapy for ivermectin toxicosis, return of menace, PLRs, and normal mentation were noted, as was improvement in ERG and serum ivermectin levels. These are the first documented cases of ivermectin-induced blindness in a dog and a foal with normal fundic examinations and attenuated ERG. ERG improved in both animals after ILE therapy. ERG may assist in the diagnosis of ivermectin toxicosis in dogs and horses. ILE therapy may hasten recovery in treatment of ivermectin-induced blindness.
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Affiliation(s)
| | | | - Ellen Weaver
- Brandon Equine Medical Center, Brandon, FL, 33511, USA
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Meekins JM, Guess SC, Rankin AJ. Retinopathy associated with ivermectin toxicosis in five cats. J Am Vet Med Assoc 2015; 246:1238-41. [DOI: 10.2460/javma.246.11.1238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Norman TE, Chaffin MK, Norton PL, Coleman MC, Stoughton WB, Mays T. Concurrent ivermectin and Solanum spp. toxicosis in a herd of horses. J Vet Intern Med 2012; 26:1439-42. [PMID: 22947027 DOI: 10.1111/j.1939-1676.2012.00996.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 06/15/2012] [Accepted: 07/26/2012] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Representatives from a herd of horses with acute onset of neurologic signs after administration of ivermectin presented for evaluation and treatment. OBJECTIVES Describe clinical signs of horses intoxicated by ingestion of Solanum sp. and administered ivermectin. ANIMALS Six of 11 affected unrelated horses presented for evaluation and treatment. The remaining 5 affected horses were treated at the farm. Four additional horses, housed separately, were unaffected. METHODS Case series is presented. Serum ivermectin concentrations were evaluated in the 6 hospitalized horses. The remnants of the tubes of ivermectin paste were analyzed for ivermectin concentration. The hay fed to the affected horses was analyzed for the presence of toxic plants. RESULTS Serum ivermectin concentrations were higher than expected, given the dosage of ivermectin administered. The ivermectin concentration remaining in the administration tubes did not exceed specifications. The hay was heavily contaminated by 2 Solanum species. All horses returned to normal neurologic function with supportive care. CONCLUSIONS AND CLINICAL IMPORTANCE Horses might exhibit signs of ivermectin toxicity after appropriate dosing of the drug if they concurrently consume toxic plants of the Solanum family.
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Affiliation(s)
- T E Norman
- Department of Large Animal Clinical Sciences, Texas A&M University College of Veterinary Medicine and Biomedical Sciences, College Station, TX 77843, USA.
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Abstract
The macrocyclic lactone endectocides such as ivermectin, abamectin, selamectin and moxidectin have revolutionized the treatment of parasitic diseases in animals, being active against internal and external parasites. Ivermectin was introduced into veterinary medicine in the 1980s and since that time a number of related compounds have been introduced. In the treatment of internal parasites they complement the use of levamisole and the benzimidazoles, but in recent years they have found utility in treating external insect parasites. These agents show very low levels of toxicity under most circumstances. However, they are neurotoxic particularly in subpopulations of animals with mutations in the MDR1 gene. Toxicity may be also seen during off-label use, possibly because the doses used have been extrapolated from use in other animals. Regardless of these considerations, the macrocyclic lactone endectocides are extremely effective and safe drugs in the treatment of parasitic diseases of animals.
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Affiliation(s)
- K N Woodward
- TSGE, Concordia House, St James Business Park, Grimbald Crag Court Knaresborough, North Yorkshire UK.
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Dawson DR. Toxins and adverse drug reactions affecting the equine nervous system. Vet Clin North Am Equine Pract 2011; 27:507-26. [PMID: 22100042 DOI: 10.1016/j.cveq.2011.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This article provides an overview of the more common toxins and adverse drug reactions, along with more rare toxins and reactions (Table 1), that result in neurologic dysfunction in horses. A wide variety of symptoms, treatments, and outcomes are seen with toxic neurologic disease in horses. An in-depth history and thorough physical examination are needed to determine if a toxin or adverse drug reaction is responsible for the clinical signs. Once a toxin or adverse drug reaction is identified, the specific antidote, if available, and supportive care should be administered promptly.
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Affiliation(s)
- Dominic R Dawson
- William Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, One Garrod Avenue, Davis, CA 95616, USA.
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Ivermectin effects on motor coordination and contractions of isolated rat diaphragm. Res Vet Sci 2010; 91:426-33. [PMID: 20971486 DOI: 10.1016/j.rvsc.2010.09.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 07/20/2010] [Accepted: 09/23/2010] [Indexed: 11/21/2022]
Abstract
Ivermectin, the antiparasitic drug from the macrocyclic lactones class raises attention due to its high efficiency against nematodes and arthropods and very specific toxic and side effects that it may produce in host. Dominant clinical symptoms of adverse effects and toxicity of ivermectin in animals are tremor, ataxia, CNS depression and coma which often results in mortality. In our study increasing intravenous doses of ivermectin, (6 or more times higher than therapeutic dose: 1.25, 2.5, 3.75, 5.0, 6.25 and 7.5 mg/kg), caused dose-dependent disturbance of motor coordination in treated rats. The median effective dose (ED50) that was able to impair the rota-rod performance in rats treated 3 min before testing was 2.52 mg/kg. This effect weakens over time, while in the rats treated 60 min before the rota-rod test, ED50 of ivermectin was 4.21 mg/kg. Whereas, all tested doses of ivermectin did not cause any other clinical symptoms of toxicity. Ivermectin has no effect on the contractions of isolated diaphragm caused by the EFS, which effectively blocked mecamylamine (100 μM) and pancuronium (1 and 2 μM). Effect on motor coordination is the first detectable clinical symptom of ivermectin toxicity and apparently is a result of its central effects.
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