Abstract:Infection by Rhodococcus equi is considered one of the major health concerns for foals worldwide. In order to better understand the disease’s clinical and pathological features, we studied twenty cases of natural infection by R. equi in foals. These cases are characterized according to their clinical and pathological findings and immunohistochemical aspects. Necropsy, histologic examination, bacterial culture, R. equi and Pneumocystis spp. immunohistochemistry were performed. The foals had a mean age of 60 day… Show more
“…Macrophages occasionally contain myriad coccobacillary basophilic gram-positive bacteria. Lung lesions may also include multinucleated giant cells, multifocal thrombosis, interstitial and alveolar edema, and tissue necrosis 140 . In humans treated with immunosuppressants for organ transplantation, R. equi- related lung lesions include inflammation of the lung parenchyma, with foamy histiocytic infiltration.…”
Section: Bacterial Infectionmentioning
confidence: 99%
“…Diagnosis. In addition to the characteristic histopathologic findings of pyogranulomatous pneumonia with intracytoplasmic bacteria in the macrophages infiltrating the lesions, positive staining for R. equi in intralesional macrophages is a potential tool for definitive diagnosis 140 . However, obtaining an appropriate antibody for IHC analysis is sometimes difficult.…”
Nonhuman primates (NHPs), which have many advantages in scientific research and are often the only relevant animals to use in assessing the safety profiles and biological or pharmacological effects of drug candidates, including biologics. In scientific or developmental experiments, the immune systems of animals can be spontaneously compromised possibly due to background infection, experimental procedure-associated stress, poor physical condition, or intended or unintended mechanisms of action of test articles. Under these circumstances, background, incidental, or opportunistic infections can seriously can significantly complicate the interpretation of research results and findings and consequently affect experimental conclusions. Pathologists and toxicologists must understand the clinical manifestations and pathologic features of infectious diseases and the effects of these diseases on animal physiology and experimental results in addition to the spectrum of infectious diseases in healthy NHP colonies. This review provides an overview of the clinical and pathologic characteristics of common viral, bacterial, fungal, and parasitic infectious diseases in NHPs, especially macaque monkeys, as well as methods for definitive diagnosis of these diseases. Opportunistic infections that can occur in the laboratory setting have also been addressed in this review with examples of cases of infection disease manifestation that was observed or influenced during safety assessment studies or under experimental conditions.
“…Macrophages occasionally contain myriad coccobacillary basophilic gram-positive bacteria. Lung lesions may also include multinucleated giant cells, multifocal thrombosis, interstitial and alveolar edema, and tissue necrosis 140 . In humans treated with immunosuppressants for organ transplantation, R. equi- related lung lesions include inflammation of the lung parenchyma, with foamy histiocytic infiltration.…”
Section: Bacterial Infectionmentioning
confidence: 99%
“…Diagnosis. In addition to the characteristic histopathologic findings of pyogranulomatous pneumonia with intracytoplasmic bacteria in the macrophages infiltrating the lesions, positive staining for R. equi in intralesional macrophages is a potential tool for definitive diagnosis 140 . However, obtaining an appropriate antibody for IHC analysis is sometimes difficult.…”
Nonhuman primates (NHPs), which have many advantages in scientific research and are often the only relevant animals to use in assessing the safety profiles and biological or pharmacological effects of drug candidates, including biologics. In scientific or developmental experiments, the immune systems of animals can be spontaneously compromised possibly due to background infection, experimental procedure-associated stress, poor physical condition, or intended or unintended mechanisms of action of test articles. Under these circumstances, background, incidental, or opportunistic infections can seriously can significantly complicate the interpretation of research results and findings and consequently affect experimental conclusions. Pathologists and toxicologists must understand the clinical manifestations and pathologic features of infectious diseases and the effects of these diseases on animal physiology and experimental results in addition to the spectrum of infectious diseases in healthy NHP colonies. This review provides an overview of the clinical and pathologic characteristics of common viral, bacterial, fungal, and parasitic infectious diseases in NHPs, especially macaque monkeys, as well as methods for definitive diagnosis of these diseases. Opportunistic infections that can occur in the laboratory setting have also been addressed in this review with examples of cases of infection disease manifestation that was observed or influenced during safety assessment studies or under experimental conditions.
“…Histologically, the mucosa and submucosa are expanded by pyogranulomas with variable numbers of intrahistiocytic and free gram-positive coccobacilli 100,146 (Fig.17). A similar pyogranulomatous infiltrate is noted within the regional lymph nodes.…”
Section: Bacterial Pathogensmentioning
confidence: 99%
“…A similar pyogranulomatous infiltrate is noted within the regional lymph nodes. 100 Diagnosis. Antemortem diagnosis may be challenging, and it is based on clinical signs, coupled with imaging and detection of virulent strains of R. equi in feces.…”
Section: Rhodococcus Equimentioning
confidence: 99%
“…Microscopic pathology. Histologically, the mucosa and submucosa are expanded by pyogranulomas with variable numbers of intrahistiocytic and free gram-positive coccobacilli 100,146 (Fig. 17).…”
Enteritis, colitis, and enterocolitis are considered some of the most common causes of disease and death in horses. Determining the etiology of these conditions is challenging, among other reasons because different causes produce similar clinical signs and lesions, and also because some agents of colitis can be present in the intestine of normal animals. We review here the main bacterial and viral causes of enterocolitis of horses, including Salmonella spp., Clostridium perfringens type A NetF-positive, C. perfringens type C, Clostridioides difficile, Clostridium piliforme, Paeniclostridium sordellii, other clostridia, Rhodococcus equi, Neorickettsia risticii, Lawsonia intracellularis, equine rotavirus, and equine coronavirus. Diarrhea and colic are the hallmark clinical signs of colitis and enterocolitis, and the majority of these conditions are characterized by necrotizing changes in the mucosa of the small intestine, colon, cecum, or in a combination of these organs. The presumptive diagnosis is based on clinical, gross, and microscopic findings, and confirmed by detection of some of the agents and/or their toxins in the intestinal content or feces.
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