P‐87 Alopecia in two guinea pigs due to hypopodes of Acarus farris

Mites are frequent agents of skin diseases in veterinary dermatology, particularly in rodents. The authors report an original case of infestation in two guinea pigs of the same household. Two adult guinea pigs were presented with a 3‐month history of alopecia, matted hair, erythema, scales and mild pruritus. The first guinea pig showed almost complete truncal alopecia with mild scaling, whereas the other one had only recently developed mild alopecia of the abdomen and mild pruritus. Numerous live, long‐legged mites were present both in adhesive tape and skin scrapings. Mycology (Wood's lamp and DTM agar culture) was negative. Histopathological examination of a skin biopsy did not reveal any significant inflammatory disease and morphological changes were limited to hair follicles in the telogen phase. Mites were identified as hypopodes of Acarus farris (Acaridae), but no adult stages were present. Hypopodes were also found in the hay. Control was obtained with acaricidal treatment with Phoxim 0.05% once weekly for 4 weeks, and the elimination of contaminated hay. The lesions and the alopecia resolved rapidly. Hypopodes are additional nymphal stages of some mites of the suborder Astigmata. They develop for dispersing or dormancy under disadvantageous conditions. They can be active or inert, and some can be phoretic on the skin surface or intrafollicular. Although nonparasitic, they may cause dermatitis. Acarus farris have been rarely mentioned in the literature as a cause of dermatitis. This condition could be underdiagnosed or misdiagnosed in veterinary dermatology. Funding: Self‐funded.     

Osteodystrophia fibrosa in two guinea pigs.

Two adult guinea pigs were examined because they were lethargic and reluctant to walk. Additionally, I guinea pig had otitis media, and the other had dental malocclusion. Both guinea pigs had been fed a commercially available diet of cereals and pellets enriched with vitamin C and formulated for this species. Radiographically, the guinea pigs had coarse trabecular bone patterns, skeletal deformations, pathologic fractures, and polyarthritic degenerative joint disease. A double cortical line was also evident on several long bones, the pelvis, and the vertebrae. A diagnosis of osteopenia was confirmed by use of dual-energy x-ray absorptiometry. Analysis of a food sample fed to 1 guinea pig revealed calcium and phosphorus contents of 0.524 and 0.425%, respectively (Ca:P ratio, 1.23:1). Microscopic examination of bone tissue from both guinea pigs revealed severe fibrous osteodystrophy. Nutritional secondary hyperparathyroidism caused by calcium-phosphorus imbalance was considered to be the underlying cause of osteodystrophia fibrosa in both guinea pigs.     

Positive Streptobacillus moniliformis PCR in guinea pigs likely due to Leptotrichia spp

Streptobacillus moniliformis is a zoonotic bacterium. We obtained positive S. moniliformis PCR results in oral swab samples from guinea pigs from an experimental colony and the breeding colony of origin. Comparison of the DNA sequence of an amplicon with deposited 16S rDNA sequences revealed that Leptotrichia sp. can be the source of a false positive S. moniliformis PCR outcome.     

Ultrasonographic detection of abdominal abscess in two guinea pigs

Two guinea pigs (Cavia porcellus) with clinical signs of anorexia, weight loss, depression and abdominal enlargement were examined. During ultrasound examination, a fluid-filled anechogenic structure 3-4 cm in diameter, with echogenic spots and a highly echogenic thick wall, was found in the pelvic region in one case and connected to the liver in the other case. An abscess or a cyst was suspected and surgical treatment including laparotomy was performed. By histopathological examination performed after surgery, a liver abscess was diagnosed in one guinea pig and an abscess in the pelvic region in the other animal.     

Morphological changes in brucellosis in guinea pigs due to experimental infection with Brucella suis

Sixty-four guinea-pigs were infected with the germs of Brucella suis. biotype 2 via the vaginal, peroral, intranasal, conjunctival and subcutaneous routes. In the subcutaneous infection the length of the trial was 151 days and in the other methods of infection 56 days. As found, guinea-pigs are highly sensitive and brucellosis lesions were detected in all cases. Brucellosis was chronical and spread locally in the guinea-pigs. In the haematogenic spreading of the disease, lesions were constantly recorded in liver, spleen and lungs. In the cases of subcutaneous infection lesions were also observed in regional lymph nodes at the places of infection. The lesions had amorphous structure and regular borders. The lesions were characterized by pronounced exudation and the exudate was subject to caseous necrosis, followed by colliquation. Secondary central colliquation was regularly observed in older granulomas, so that colliquation is considered as a characteristic morphological trait of brucellosis process in guinea-pigs. Histiocytary granuloma constituted the microscopic basis of the lesions. In older granulomas the central necroses were wide and contained a large amount of nuclear detritus, owing to the karyorhexis of cells, mainly neutrophiles. In the necroses of caseous type lipoid droplets were found and calcification was observed on the 151st day. Big cells of Langhans type occurred sometimes in the histiocytary layer of granulomas; they were present most frequently in the lesions affecting lymph nodes. Interstitial pneumonia was a characteristic symptom in liver and big cells of Sternberg type were found in the granulomas. Follicular tumor was constantly observed in spleens. Morphologically detectable lesions first developed in liver after about 7 days from conjunctival infection and subcutaneous infection, after 21 days from vaginal and intranasal infection, and after 28 days from peroral infection. In the case of subcutaneous infection, granulomas were found in the regional lymph nodes on the 14th day. The most expressive lesions in organs, mainly liver, were found from the 49th to 56th day from infection.     

Posterior paralysis due to fibrocartilaginous embolism in two weaner pigs.

Acute posterior paralysis in two weaner pigs was attributed to ischemic infarction of the lumbar spinal cord due to fibrocartilaginous emboli. These arterial and venous emboli were assumed to have originated from the nucleus pulposus of one or more intervertebral discs. There was no indication of an initiating factor in either instance, although some form of trauma may have been involved. Lesions were not grossly evident and were limited to one or two lumbar segments. Although it appears to be a rare occurrence, fibrocartilaginous embolism of the spinal cord should be considered in cases of acute paralysis in pigs particularly when gross lesions are absent.     

Conjunctival dermoid in two guinea pigs: a case report

Clinical and histologic findings of conjunctival dermoids in two unrelated guinea pigs are described. The dermoids were treated surgically by resection with superficial lamellar keratectomy and corneal epithelial debridement. Histologically the dermis underneath a stratified squamous keratinized and variably pigmented epithelium consisted of multiple hair follicles, with clearly visible arrectores pilorum muscles, sebaceous glands and loose vascularized fatty tissue.