A study of the histological classification and grading of canine malignant mammary tumours in Trinidad

Objective: Mammary gland tumors are a common occurrence in dogs, cats and humans but a rarity in other species. Histologically, grading these tumors evaluates the relevant prognostic variables which may be useful in treatment. The objective of this study was to classify canine malignant mammary tumours according to their morphological and staining characteristics using a standardized histologic classification scheme. Design and Methodology: A total of n = 78 canine mammary gland tumours (CMTs) were diagnosed during the period March 2013 to April 2017. CMTs were evaluated subsequent to routine tissue processing for microscopic evaluation followed by statistical analyses. Results: The two main tumour groups examined were malignant epithelial neoplasms and malignant epithelial neoplasms ­ special types, n= 69 (88.5%) and n= 9 (11.5%) respectively. The majority, n= 62 (79.5%) of tumours were classified as low grade or well differentiated (grade 1), n= 14 (17.9%) of tumours were intermediate grade or moderately differentiated (grade 2) and n= 2 (2.6%) of tumours were classified as high grade or poorly differentiated (grade 3). The significance of age or breed predilection could not fully be determined with this small sample size n = 78, however, all the dogs in this study were female. Conclusion: This study is the first of its kind to be conducted in Trinidad, which fully applies a standardized classification scheme as an independent prognostic indicator of CMTs.

Cytokines changes in beagle dogs vaccinated and challenged with virulent Leptospira strains

Objective: To determine the immune response of dogs by measuring the levels of cytokines tumour necrosis factor (TNF) α, interleukin (IL)-4 and interferon (IFN) γ pre- and post-vaccination with a locally produced killed whole-celled Leptospira vaccine. Design and Methodology: Three separate vaccine-challenge experiments involving 21 beagle dogs were conducted. Study 1 (duration of immunity), used 6 vaccinated and 3 non-vaccinated (control) dogs. Vaccination was done at 12 and 16 weeks of age and challenged at 12 months of age with 1-2.5 x 108 live Leptospira. Study 2 (onset of immunity) also contained the same number of dogs as study 1. Vaccination was done at 12 and 16 weeks of age and challenged at 18 weeks of age. Study 3 (onset of immunity study), as study 2, used 4 vaccinated and two control dogs but challenged with 1-2.5 X 109 live Leptospira. Blood samples were collected to measure the levels of TNF α, IL-4 and IFN γ in dogs 2 days pre-challenge and daily thereafter until day 7 post-challenge. Results: For cytokine TNF α, pre-challenge levels for Study 1, 2 and 3 were 0.0000, 0.0755 and 0.0705 pg/ml which increased to a maximum post-challenge level of 49.05 pg/ml, 0.47 pg/ml and 1.667pg/ml respectively. For cytokine IL-4 and IFN γ the level increased from 0.00 pg/ml to a maximum post-challenge level of 52.67 pg/ml, 243.34 pg/ml and 989.14 pg/ml; and 281.91 pg/ml, 1223.85 pg/ ml and 1778.95 pg/ml respectively. Conclusion: The locally produced Leptospira vaccine induced immune response post-challenge with live Leptospira.

Prevention of severe clinical signs and pathological lesions of leptospirosis in experimentally challenged dogs

Objective: To prevent severe clinical and pathological findings of leptospirosis in dogs vaccinated against L. interrogans serovar Copenhageni. Design and Methodology: Two vaccination-challenge experiments involving 22 dogs were performed using a vaccine prepared from formalin-killed cultures of L. interrogans serovar Copenhageni. The dogs were challenged by administering a suspension of 1 x 109 of a virulent strain of serovar Copenhageni (8 mL) at 2 weeks (Study 1: Onset of immunity) and 14 months (Study 2: Duration of immunity) after primary and secondary vaccinations. Each dog was observed for clinical signs of leptospirosis for five weeks post-challenge (PC). Any dog which showed irreversible clinical signs of leptospirosis was humanely euthanized, and a necropsy performed. Results: One (20.0 %) vaccinated puppy in Study 1 showed mild clinical signs (PC) which lasted for one day. Five (100.0 %) non-vaccinated (controls) puppies exhibited irreversible signs of acute severe leptospirosis PC, as well as significant postmortem lesions consistent with leptospiral infection. In Study 2, no clinical signs were exhibited by the vaccinated group of dogs PC, while two (40.0 %) non-vaccinated dogs exhibited mild clinical signs for 2 to 3 days, after which they recovered. Conclusions: The vaccine was successful in protecting vaccinated dogs against acute leptospirosis 2 weeks and 14 months after a vaccination schedule of two doses of the bacterin (primary and booster doses), since all vaccinated dogs were clinically normal after challenge with a virulent inoculum of serovar Copenhageni.

A review of neoplastic and non-neoplastic canine skin tumours in Trinidad from 2010-2015

This retrospective study was performed on samples submitted to the Pathology Unit of the School of Veterinary Medicine, Faculty of Medical Sciences, St. Augustine, Trinidad, during the period 2010 to 2015. A total of 471 non-inflammatory cutaneous masses were analyzed, of which 225 (47.8%) were malignant, 202 (42.9%) were benign and 44 (9.3%) were non-neoplastic. The most common malignant tumors were haemangiosarcoma, 50 (22.2%); mast cell tumour, 49 (21.8%); soft tissue sarcoma 35 (15.6%), lymphoma, 20 (8.9%) and melanoma 20 (8.9%). The most common benign tumors were haemangioma, 39 (19.3%); lipoma, 27 (13.4%), trichoblastoma, 26 (12.9%), histiocytoma 25 (12.4%), plasma cell tumor, 23 (11.4%) and papilloma 9 (4.5%). Common non-neoplastic skin lesions included collagen naevi, 26 (59.1%) and follicular cysts, 11 (25.0%). Mixed breed dogs 241 (51.2%), was most frequently represented with neoplasms followed by Rottweilers 50 (10.6%) and Pit bulls 48 (10.1%).

A Review of the Cause and Manner of Death of Suspected Animal Abuse Cases in Trinidad And Tobago, 2008-2015

Background: Forensic veterinary pathology is becoming increasingly important in investigation situations of suspected animal abuse. It is thought that the submission of suspected cases of animal abuse has increased over the past seven years in Trinidad and Tobago. Methodology: A search for owner or law-enforcement suspected animal abuse necropsy cases submitted at either the University of West Indies Veterinary Hospital or the Ministry of Agriculture, Land and Fisheries, Veterinary Diagnostic Laboratory for the period of 2008-2015 was performed. Based on pathology records and submission information, cases were categorized by signalment and cause of death (COD) or manner of injury (MOI) if the animal was euthanized. Results: A total of 84 cases of suspected animal abuse were submitted in the years 2008-2015. Although the submission of these cases decreased from 2008-2012, there has been an increased since then. The most commonly submitted animal species were dogs (74%) and sheep (7%). Of the 84 cases, only 22 (24%) had a confirmed COD/MOI. The most common confirmed COD/MOI was trauma (45%), followed by poisoning (27%). The majority of the unconfirmed COD/MOI involve suspected poisoning. Conclusions: Owners are becoming increasingly aware of the importance of pathology to help diagnose suspected animal abuse cases, and are becoming more interested in trying to prosecute those they suspect of harming their pets. Toxicological studies are currently limited, but they would be very useful in confirming cause of death for the majority of unresolved cases.

Ocular localization of mycobacterial lesions in tank-reared juvenile cobia, Rachycentron canadum.

Severe clinical mycobacteriosis with consistent ocular lesion localization was diagnosed in a population of 800 juvenile tank-reared Cobia (Rachycentron canadum) which experienced a sudden increase in mortality approximately 5 months after arriving into Trinidad and Tobago from Florida, USA. Moderate daily mortality (15-20 animals per day) persisted for just over 1 month. Moribund fish displayed circling behaviour and had an open-mouth gape upon death. Fish consistently presented with bilateral exophthalmia, corneal cloudiness and hyphema. Non-branching acid-fast rods were detected in aqueous humour touch preparations. Histological analysis revealed severe bilateral intra-ocular granulomatous responses in all specimens. Mycobacterium sp. was identified using a real-time PCR assay detecting the RNA polymerase ß-subunit (rpoB) gene in different tissue samples. Specimens did not present with characteristic granulomatous responses usually seen in viscera. To the best of our knowledge, this represents only the third documentation of piscine mycobacterial infection presenting with only localized ocular lesions, and the second documented case of mycobacteriosis in cobia. It is, however, the first documentation of an ocular presentation of mycobacteriosis in a marine species and is the first documentation of such a presentation in cobia.

Salt gland adenitis associated with bacteria in Blue Penguins (Eudyptula minor) from Hauraki Gulf (auckland, New Zealand).

Three Blue Penguins (Eudyptula minor) were rescued between July 2006 and January 2007 off the east coast of Auckland, New Zealand. They were taken to a rehabilitation center, where they subsequently died in May 2007 and were submitted for necropsy. There was unilateral enlargement of the salt glands with disseminated small, pale, and firm foci in all birds. Histologic examination of the affected glands demonstrated the presence of multifocal granulomas and areas of severe squamous metaplasia of the collecting ducts. The remaining gland had areas of hyperplasia, dysplasia, and necrosis with a severe granulomatous inflammatory reaction. Intralesional gram-negative bacteria were detected, but, unfortunately, bacterial culture was unrewarding. No further cases were observed in penguins in the subsequent year, and the primary cause of the salt gland adenitis remains uncertain.

Salt gland adenitis associated with bacteria in Blue Penguins (Eudyptula minor) from Hauraki Gulf (auckland, New Zealand)

Three blue penguins (Eudyptula minor) were rescued between July 2006 and January 2007 off the east coast of Auckland, New Zealand. They were taken to a rehabilitation center, where they subsequently died in May 2007 and were submitted for necropsy. There was unilateral enlargement of the salt glands with disseminated small, pale, and firm foci in all birds. Histologic examination of the affected glands demonstrated the presence of multifocal granulomas and areas of severe squamous metaplasia of the collecting ducts. The remaining gland had areas of hyperplasia, dysplasia, and necrosis with a severe granulomatous inflammatory reaction. Intralesional gram-negative bacteria were detected, but, unfortunately, bacterial culture was unrewarding. No further cases were observed in penguins in the subsequent year, and the primary cause of the salt gland adenitis remains uncertain.

Acute B-cell lymphoblastic leukaemia in a 5-month-old boar.

CASE HISTORY: A 5-month-old mixed-breed boar presented with lethargy, weakness and anorexia of 1 week's duration. CLINICAL FINDINGS AND DIAGNOSIS: The boar had an elevated heart rate, slow capillary refill time and cyanotic skin over the ears; it was also severely anaemic. A necropsy revealed scattered petechial haemorrhages, small subcapsular white nodules on the kidneys, a nodule in the parenchyma of one testis, creamy-white bone marrow, a preputial diverticulum, and an ulcer of the pars oesophagea of the stomach. Cytology of peripheral blood and bone marrow identified large numbers of lymphoblasts, which were demonstrated using immunocytochemistry to be of B-cell origin. Histological examination of multiple organs also showed lymphoblastic infiltration. DIAGNOSIS: B-cell lymphoblastic leukaemia with secondary infiltration of lymphoid organs, kidneys, testis and preputial skin. CLINICAL RELEVANCE: This is the fi rst known reported case of acute B-cell lymphoblastic leukaemia in swine.