M. Andrada

Metastatic melanoma causing spinal cord compression in a horse

MELANOMAS represent 6 to 15 per cent of skin tumours seen in the horse (Pulley and Stannard 1990). They are most common in ageing grey horses and result in multiple dermal tumours, primarily involving the ventral tail, perineum and external genitalia (Baker and Lehland 1975). They are described as slow growing, locally invasive masses, that usually do not metastasise (Pulley and Stannard 1990). Neoplasia causing neurological dysfunction has been reported as a rare occurrence in the horse (Traver and others 1977). Secondary neoplasms that cause spinal cord compression and ataxia in horses include lymphosarcoma, plasma cell myeloma, pheochromocytoma and fibrosarcoma (Schott and others 1990). This report relates a case of posterior paresis, bladder paralysis and perineal anaesthesia due to a metastatic melanoma at the lumbar level of the vertebral column of an aged grey Arabian horse. A 12-year-old female grey Arabian horse was observed in lateral recumbency with an acute onset of paralysis after a 10-day history of paresis affecting the pelvic limbs. The horse was capable of adopting sternal recumbency to eat and drink to maintain hydration but was anorectic. Other clinical signs included tachypnoea, hyperthermia, hyperaemia and oedema of the conjunctiva. Physical examination showed numerous black cutaneous nodules, 2 to 6 cm in diameter,

Correlating the immune response with the clinical–pathological course of persistent mastitis experimentally induced by Mycoplasma agalactiae in dairy goats

To correlate the clinical course of mycoplasma mastitis with its immune response, right mammary glands of 15 lactating goats were inoculating with 10(10) colony-forming units (cfu) of Mycoplasma agalactiae (Ma). Before sacrificing the animals at 5, 15 or 45 days post-inoculation (dpi), blood Ma antibody titres and milk mycoplasma colony and somatic cell counts were monitored. Ma colonised the mammary gland and milk counts increased to over 10(12)cfu/ml within 5 dpi. During this period, an innate immune response involving neutrophils and macrophages was observed, and Ma antigen appeared in the degenerated acinar epithelium. From 7 dpi, a specific antibody response coincided with reduced viable mycoplasmas in milk. The humoral immune response was limited; by 37 dpi, all animals scored negative for anti-Ma antibodies, and around 10(8)cfu/ml were shed. Results indicate an early immune response to Ma inoculation unable to control mycoplasmal invasion. An ensuing humoral response, despite reducing the mycoplasma burden, leads to chronic, persistent infection.

Serological study of contagious agalactia in herds of goats in the Canary Islands

An indirect ELISA, using local strains of Mycoplasma agalactiae and Mycoplasma mycoides subspecies mycoides large colony (MmmLc), was applied to evaluate the seroprevalence of M agalactiae and MmmLc in flocks of goats on each of the Canary Islands. In total 3890 samples of serum were collected from 204 flocks. The results indicated that the seroprevalence of both organisms is high on all the islands; average values of 55 per cent and 67 per cent were recorded, respectively, for M agalactiae and MmmLc.

Isolation of an Eimeria ninakohlyakimovae field strain (Canary Islands) and analysis of its infection characteristics in goat kids.

The current study was conducted to isolate a field strain of Eimeria ninakohlyakimovae, characterize its infectivity and the response to challenge under experimental conditions. The isolated strain (GC) induced a prepatent period of 14-15 days p.i., a patency of 7±2 days and a noticeable pathogenicity in infected goat kids. Challenge trials resulting in a decrease of oocysts per gram counts as well as a milder intensity of clinical signs in re-infected animals indicated the capacity of this strain to induce protective immune response. Altogether, the data reported in the present study suggest that the strain E. ninakohlyakimovae GC is a useful tool for the investigation of mechanisms of pathogenicity as well as host protective immune response in caprine coccidiosis, representing a valuable prerequisite for the development of future strategies in prophylaxis and control of this important parasitic disease in goat.

Last âÂÂAtypicalâ Beaked Whales Mass Stranding in the Canary Islands (July, 2004)

In July 2004, four Ziphius cavirostris stranded in the Canary Islands several days after an international naval exercises were conducted north of the Canary Islands. During the maneuvers high intensity mid-frequency sonar was used. Three of the animals were fully necropsied. Abundant fresh non-digestive aliment was found in all stomachs. Hemorrhages were a constant finding in several organs. Although “ in vivo” gas embolism could not be established due to decomposition, systemic fat embolism was diagnosed in all three beaked whales. Epidemiological and pathological findings were highly consistent with an “atypical” beaked whale mass stranding that was temporally and spatially associated with sonar. This was the last atypical mass stranding in the Canary Islands once an antisonar moratorium was established around the islands, following the EU parliament recommendation and Spanish government resolution in 2004.

Herpes virus infection associated with interstitial nephritis in a beaked whale (Mesoplodon densirostris)

BackgroundThe capacity for herpesvirus to cause disease in cetaceans is unclear and may be varied depending on the different conditions of individuals and between different species. Kidney pathology and intralesional virus-associated infection have been rarely reported in cetaceans.ResultOn April 2004, an old adult male Blainville’s beaked whale (Mesoplodon densirostris) 420 cm long with a poor body condition was stranded on Tenerife Island. During necropsy, no gross lesions were observed in the kidneys. However, membranous glomerulonephritis, multifocal interstitial lymphoplasmacytic nephritis and acute multifocal necrotizing tubulointerstitial nephritis with intranuclear inclusion bodies was diagnosed by histological analysis. Tissue samples were submitted for bacteriological analysis and molecular viral screening.ConclusionA novel alpha herpesvirus associated with interstitial nephritis was identified in an old adult male Blainvilles beaked whale (M. densirostris) with a poor body condition stranded in the Canary Islands. This report suggests that identification of herpesvirus infection could be used as a differential diagnosis for interstitial nephritis in cetaceans.

Immunization with Eimeria ninakohlyakimovae-live attenuated oocysts protect goat kids from clinical coccidiosis.

Caprine coccidiosis, affecting mainly young goat kids around the weaning period, is worldwide the most important disease in the goat industry. Control of caprine coccidiosis is increasingly hampered by resistances developed against coccidiostatic drugs leading to an enhanced need for anticoccidial vaccines. In the current study we conducted an oral immunization trial with live attenuated sporulated Eimeria ninakohlyakimovae oocysts. Sporulated E. ninakohlyakimovae oocysts were attenuated by X-irradiation technique. The experimental design included a total of 18 goat kids divided into the following groups: (i) animals immunized with attenuated E. ninakohlyakimovae oocysts at 5 weeks of age and challenged 3 weeks later with non-irradiated homologous oocysts (group 1); (ii) animals infected with non-attenuated E. ninakohlyakimovae oocysts at 5 weeks of age and challenged 3 weeks later with non-attenuated homologous oocysts (group 2); (iii) animals primary-infected with untreated E. ninakohlyakimovae oocysts at 8 weeks of age (control of the challenge infection, group 3); (iv) non-infected control animals (group 4). Goat kids immunized with live attenuated E. ninakohlyakimovae oocysts (group 1) excreted significantly less oocysts in the faeces (95.3% reduction) than kids infected with non-attenuated ones (group 2). Furthermore, immunization with live but attenuated oocysts resulted in ameliorated clinical coccidiosis compared to goat kids infected with untreated oocysts (group 2) and resulted in equally reduced signs of coccidiosis after challenge infection compared to acquired immunity driven by non-attenuated oocysts. Overall, the present study demonstrates for the first time that live attenuated E. ninakohlyakimovae oocysts orally administered showed almost no pathogenicity but enough immunogenicity in terms of immunoprotection. Importantly, vaccinated animals still shed low amounts of oocysts, guaranteeing environmental contamination and consecutive booster infections to sustain ongoing immunity.

Morphologic and immunohistochemical features of Merkel cells in the dog.

Merkel cells (MCs) are specialized skin receptors characterized by their particular location and close association with nerve terminals. They also are cells with a presumptive neuroendocrine function and are considered as part of the diffuse neuroendocrine system. By using commercially available monoclonal and polyclonal antibodies in samples of dog skin, MCs were properly distinguished from other clear cell types in the epidermis. They expressed cytokeratins 7, 8, 20, EpCAM, NSE, CGA, SYN, S100 protein, and NF, presented diverse cytological features and arrangements depending on the location considered, and showed pronounced heterogeneity with markedly different expression and distribution patterns for antibodies used. Anti-CK20 presented as the most reliable and specific antibody for their identification. The present study increases our knowledge of MCs and establishes a basis for future studies of the role(s) of the MCs in diseased tissues of the dog skin, including the cutaneous neuroendocrine (Merkel cell) tumour.

Histopathological Muscle Findings May Be Essential for a Definitive Diagnosis of Suspected Sharp Trauma Associated with Ship Strikes in Stranded Cetaceans

Ship strikes are a major issue for the conservation of may cetacean species. Certain gross and microscopic criteria have been previously reported for establishing a diagnosis of death due to ship strikes in these animals. However, some ship-strike injuries may be masked by advanced carcass decomposition and may be undetectable due to restricted access to the animals. In this report we describe histopathological muscular findings in 13 cetaceans with sharp trauma from ship strikes as the cause of death. Skeletal muscle samples were taken from the incision site and from the main locomotor muscle, the longissimus dorsi, in areas not directly affected by the sharp injury. The microscopic findings in tissues from both sites mainly consisted of haemorrhages; oedema; flocculent, granular or/and hyalinised segmentary degeneration; contraction band necrosis; and discoid degeneration or fragmentation of myofibres. We propose that skeletal muscle histopathology provides evidence of ante-mortem injuries even if the sample was taken elsewhere in the carcass and not only within or adjacent to the sharp trauma site and despite the advanced decomposition of some of the carcasses. This method helps to establish the diagnosis of ship strike as the cause of death.

Primary central nervous system T-cell lymphoma in a common dolphin (Delphinus delphis).

This report describes the pathological findings in an adult female short-beaked common dolphin (Delphinus delphis) stranded alive in the Canary Islands. Necropsy examination revealed the presence of a nodular neoplastic growth in the central nervous system (CNS) at the level of the thalamus. Microscopical examination revealed the mass to be a lymphoma and immunohistochemical labelling demonstrated a T-cell origin. No significant lesions were observed in other organs, including lymphoid organs. This is the first report of a primary T-cell lymphoma in the CNS in cetaceans.