Enrique Paredes

Case Report: Strawberry Disease in Farmed Chilean Rainbow Trout

Strawberry disease is a chronic, nonlethal skin condition that affects Rainbow Trout Oncorhynchus mykiss in the United States and several European countries, where it is also known as red-mark syndrome. We provide the first identification and characterization of three strawberry disease outbreaks occurring at two aquaculture farms in southern Chile. Clinically affected fish weighing an average of 400 g presented multiple bright-red, usually raised, skin lesions on the flank, ventral surface, and dorsal surface. A PCR using Rickettsia-like-organism (RLO)-specific primers was performed on nine affected fish, and all skin samples were positive for the RLO 16S ribosomal RNA sequence. All PCR results for Flavobacterium psychrophilum and other bacterial and viral pathogens were negative. Histopathological examination of the skin lesions revealed extensive dermatitis, with severe lymphocytic infiltration in advanced cases. This report is the first to describe strawberry disease in farmed Chilean Rainbow Trout. Additional studies are needed to evaluate the risk for Rainbow Trout culture; fish challenge experiments should be performed to fulfill Kochs postulates and to demonstrate that RLO is the cause of this disease. Received December 27, 2014; accepted October 23, 2015.

Paratuberculosis or avian tuberculosis in red deer with chronic diarrhea

SUMMARY Mycobacterium avium subsp. paratuberculosis ( Map ) is the etiological agent of paratuberculosis. In Chile, information about Map isolation from both domestic ruminant and wildlife species has been accumulating, but it has extended to other species. In Chile, deer farming activity has been focused in hunting and meat production. No paratuberculosis surveillance has been reported for these source herds. In the present study, chronic diarrhea and poor body condition in some animals belonging to a deer farm was informed. Four adult affected hinds were euthanized under suspicion of paratuberculosis. In all animals macroscopic and microscopic lesions consistent with paratuberculosis were observed. Map -positive culture results from faecal and tissue samples, complemented with positive-PCR-results from fixed tissues are informed. Evidence has been found on cattle and deer populations being connected since molecular characterization of the Map isolated from deer lack of variation between the cattle control strain. The latter could indicate that both species share the same bacteria, suggesting there is interspecies transmission. Complementary diagnostic methods were accurate to diagnose paratuberculosis and to differentiate the clinical deer case from other mycobacterial infection. The epidemiological findings suggest that the infection in the deer farm could be transmitted from a cattle herd, making this the first reported case of paratuberculosis in deer farm in Chile.

Recovery of black-necked swans, macrophytes and water quality in a Ramsar wetland of southern Chile: Assessing resilience following sudden anthropogenic disturbances

In 2004 migration and mortality for unknown reasons of the herbivorous Black necked swan (Cygnus melancorhyphus (Molina, 1782)) occurred within the Río Cruces wetland (southern Chile), a Ramsar Site and nature sanctuary. Before 2004, this wetland hosted the largest breeding population of this water bird in the Neotropic Realm. The concurrent decrease in the spatial occurrence of the aquatic plant Egeria densa Planch. 1849 - the main food source of swans - was proposed as a cause for swan migration and mortality. Additionally, post-mortem analyses carried out on swans during 2004 showed diminished body weight, high iron loads and histopathological abnormalities in their livers, suggesting iron storage disease. Various hypotheses were postulated to describe those changes; the most plausible related to variations in water quality after a pulp mill located upstream the wetland started to operate in February 2004. Those changes cascaded throughout the stands of E. densa whose remnants had high iron contents in their tissues. Here we present results of a long-term monitoring program of the wetland components, which show that swan population abundance, body weights and histological liver conditions recovered to pre-disturbance levels in 2012. The recovery of E. densa and iron content in plants throughout the wetland, also returned to pre-disturbance levels in the same 8-year time period. These results show the temporal scale over which resilience and natural restoring processes occur in wetland ecosystems of temperate regions such as southern Chile.

Distribución y viabilidad de cisticercos de Taenia saginata en los cortes de carne de la canal de bovinos naturalmente infectados

Se determino la distribucion anatomica y viabilidad de los cisticercos de Taenia saginata en bovinos naturalmente infectados, faenados en el sur de Chile. Los animales fueron inspeccionados post mortem segun los procedimientos chilenos oficiales en los puntos obligatorios: corazon, lengua, maseteros, esofago, diafragma y superficie de canal. Se tomaron al azar 20 canales de bovinos diagnosticados positivos a la inspeccion, y sus mitades izquierdas fueron despostadas en los 33 cortes oficiales; estos fueron completamente disecados en laminas de aproximadamente 0,5 cm de grosor, contabilizando el numero de cisticercos encontrados por inspeccion visual en cada corte. Lesiones compatibles con cisticercos de Taenia saginata se encontraron a la inspeccion oficial en 148 bovinos (0,5% de prevalencia), encontrando 64,9% en corazon, 33,8% en musculos maseteros, 0,7% en esofago y 0,7% en la canal. Al examen histologico de las lesiones, se encontro que 82,9% eran cisticercos no viables (degenerados) y solo 5,1% eran viables; 10,7% correspondieron a otros diagnosticos (principalmente miositis, seguido de miocarditis en corazon y actinobacilosis en lengua) y en 1,3% de los casos no se encontraron alteraciones. Se encontraron 14 lesiones compatibles con cisticercosis en las 20 canales positivas a cisticercos de Taenia saginata a la inspeccion; todas fueron confirmadas positivas al analisis histologico y todas eran quistes degenerados. Estos cisticercos estaban distribuidos en filete, tapapecho, asiento, ganso, plateada, asado de tira, posta negra, tapabarriga, posta de paleta y entrana. Se concluye que la posibilidad de encontrar cisticercos en cortes de carne es limitada, especialmente en animales infectados en forma leve, como sucede en Chile.

Immunosuppressive Syndrome in Juvenile Black-Faced Ibises (Theristicus melanopis melanopis) in Southern Chile

SUMMARY. In the austral summer of 2011, in the rural area of Villarrica county, southern Chile (39°16′S, 72°19′W), seven black-faced ibis juveniles (approximately 4 mo old) were observed in the field with weakness; they were unable to follow the group and struggling to take flight. Three of these birds were euthanatized, and complete necropsies were performed. Gross examination showed severe infestation with Colpocephalum trispinum and Ardeicola melanopis lice, moderate emaciation, pale musculature, bursal atrophy, and severe hemorrhagic enteritis due to a heavy proventricular and intestinal infection with Porrocaecum heteropterum nematodes. Fungal pneumonia and severe lymphoid depletion on thymus, spleen, and bursa were diagnosed by microscopic examination. Bursal lesions included apoptosis and necrosis of lymphoid cells, and several cystic follicles. The presence of severe lymphoid depletion associated with fungal pneumonia and severe external and internal parasite infections suggest the presence of an immunosuppressive syndrome in these birds that caused the death of several black-faced ibis juveniles in southern Chile during the summer of 2011.

Computer tomographic imaging in 4 dogs with primary nasal canine transmissible venereal tumor and differing cellular phenotype

Primary nasal canine transmissible venereal tumor (CTVT) without genital affection is uncommon. The aim of this report was to describe the primary nasal CTVT findings and CT staging in 4 dogs with different cytological phenotypes. Three male dogs and 1 bitch were evaluated for their chronic histories of sneezing, snoring, mucopurulent nasal discharge and nasal deformation. Cytological examination of nasal secretions suggested CTVT, confirmed by histopathological examination and LINE‐1/c‐myc. Males had the plasmacytoid phenotype of CTVT, and the bitch had the lymphocytoid phenotype. CTVT were staged based on the CT findings using modified Adams staging system. The bitch was classified as stage 1, 2 males were classified as stage 3 and 1 male as stage 4. All dogs had a complete tumoral remission after chemotherapy. Plasmacytoid phenotype was identified in cases with most important damage of the nasal cavity. However, the cytological type did not affect the response to chemotherapy.

Periurethral Vascular Hamartoma in a 6-Month-Old Foal With Idiopathic Hematuria: New Differential Diagnosis

ABSTRACT Hamartomas are nonmalignant masses of normal tissue organized in a chaotic manner. Here, we describe a 6‐month‐old 120 kg Chilean Criollo foal that manifested chronic hematuria observed since birth. Severe anemia and lack of development were the main complaints of this referral. The foal was depressed and in poor body condition, and had lagged development and a coarse haircoat. Mucous membranes were pale, and numerous blood clots were observed toward the end of micturition. Severe normocytic normochromic anemia was confirmed by hematological analysis; there were no significant findings in serum biochemistry or coagulation tests. Transabdominal ultrasonography and urinary tract endoscopy yielded no clinically relevant results. Empirical treatment was initiated on a tentative diagnosis of idiopathic renal hematuria (dexamethasone 0.1 mg/kg [0.045 mg/lb], q 24 hours, IV, sodium ceftiofur 2.2 mg/kg [0.99 mg/lb], IM, q 24 hours, and blood transfusions), but the foals condition further deteriorated, warranting euthanasia. Necropsy revealed a vascular malformation on the extraluminal portion of the proximal urethra at the bladder junction, with a 3 mm urethral communication. Histopathologic examination confirmed this mass to be a hamartoma of vascular origin, which incidentally communicated with the urethral lumen and led to progressive blood loss. In this case, the location of this malformation impeded its discovery and ultimately an accurate diagnosis. Hamartomas are currently not listed as a differential diagnosis for bleeding‐related urinary tract disorders in the modern literature; therefore, we propose that they should be considered as a differential diagnosis in cases of unexplained or refractory idiopathic hematuria. HighlightsUnexplained chronic hematuria and anemia in a 6‐month‐old Chilean Criollo foal with ill thrift.A vascular malformation communicating with the urethral lumen caused progressive blood loss.This is the first description of a periurethral vascular hamartoma in horses.

Pathological Findings in Wild Rats (Rattus rattus) Captured at Guafo Island, Northern Chilean Patagonia

The black rat (Rattus rattus) is an invasive species and potential reservoir of significant pathogens of man, domestic animals and wildlife. During the 2012-2014 austral summers, 201 black rats were captured and examined on the uninhabited Guafo Island, in Northern Chilean Patagonia (43.593029°S, 74.713481°W). The mite Ornithonyssus bacoti caused lymphoplasmacytic and eosinophilic dermatitis in all infected rats (105/210, 52%), but no skin lesions were observed in rats infected with Nosopsyllus spp. and Plocopsylla spp. fleas. Eighty-eight rats (44%) had mild lymphoplasmacytic and eosinophilic enterocolitis and 61 of these rats were infected with the nematode Heterakis spumosa. In the liver, 63 animals (31%) had areas of necrosis with histiocytic and eosinophilic inflammation associated with multiple Calodium hepaticum eggs, and in 15 cases there was co-infection with several Taenia taeniaeformis strobilocerci. Mild interstitial lymphoplasmacytic sialadenitis with intranuclear inclusion bodies, suggesting cytomegalovirus infection, was observed in 28 rats (15%). In the lung, alveolar histiocytosis (69 rats, 34%) and perivascular lymphocytic infiltrates (46 rats, 23%) were the most common findings. There was mild to moderate lymphoplasmacytic interstitial nephritis in 52 rats (26%) and in 15% of these cases Leptospira spp. antigen was detected in the distal renal tubules. Some of the diseases of black rats on Guafo Island are likely to play a role in rat population dynamics. The endemic Guafo Island long-clawed mole mouse (Geoxus lafkenche), sea lions and fur seals may be at risk for infection by some of these rat pathogens.

Carcinoma mamario en un canino macho: caracterización clínica e inmunohistoquímica

Las neoplasias mamarias en perros machos son poco comunes, no superando el 2% de la totalidad de casos de tumores mamarios en machos y hembras. Estos han mostrado ser en su mayoria de baja malignidad y positivos a la presencia del receptor de estradiol α. En este reporte se presenta un caso de tumor mamario en un perro mestizo macho, que fue evaluado clinicamente, resuelto quirurgicamente y estudiado citologica, histologica e inmunohistoquimicamente mediante el estudio de proteinas como receptor de estradiol α y β (REα, REβ), receptor 2 del factor de crecimiento epidermico (EGFR2), receptor 2 del factor de crecimiento vascular endotelial (VEGFR2), ciclooxigenasa 2 (COX2) y antigeno nuclear de proliferacion celular (PCNA). Al examen clinico, el paciente presento una masa bien definida, llena de liquido, adyacente al prepucio y formando parte de la glandula mamaria inguinal derecha. La citologia y el estudio histologico mostraron celulas epiteliales neoplasicas concordantes con un carcinoma tubular simple de grado histologico I. Al realizar inmunodeteccion, se observo una alta expresion de REα, REβ y EGFR2 y ausencia de expresion de COX2 y VEGFR2, resultados que son concordantes con el patron clinico-histologico de la neoplasia estudiada.