Pathology and causes of death in captive meerkats (Suricata suricatta)

BACKGROUND

Meerkats (Suricata suricatta) are endemic carnivores of southern Africa and, although currently listed as "least concern" by the International Union for Conservation of Nature (IUCN) red list, there is evidence of a significant decrease in wild populations mainly attributed to effects of climate change. Little is known about diseases associated with mortality in captive meerkats.

AIM

To characterise macroscopic and microscopic lesions that accounted for the death or euthanasia in a series of captive meerkats.

MATERIAL AND METHODS

Eight captive meerkats submitted for post-mortem examination between 2018 and 2022.

RESULTS

Three animals died unexpectedly without clinical signs, 2 exhibited neurological signs, 2 collapsed after con-specific fighting and 1 showed gastrointestinal signs. Common pathological findings of this study that may be related to the death of captive meerkats included foreign bodies (trichobezoars or plastic materials) within the alimentary tract, traumatic penetrating injuries or starvation associated with abnormal social behaviours (bullying and con-specific attacks), verminous pneumonia and systemic atherosclerosis. Common incidental findings included pulmonary edema and congestion, cholesterol granulomas, pulmonary adenomas and vertebral spondylosis.

CONCLUSIONS

Non-infectious diseases outreach infectious diseases as causes of mortality in captive meerkats including, foreign bodies within the alimentary tract, con-specific attacks and systemic atherosclerosis, which is described for the first time. These data should raise concern about appropriate husbandry (e.g. environmental enrichment, cleaning of facilities and diet formulation) by zookeepers and emphasise the need for further study of meerkat mortality in both captive and wild populations.

Procyonidae, Viverridae, Hyenidae, Herpestidae, Eupleridae, and Prionodontidae

This chapter covers the diseases and pathology of multiple taxonomic groups within the order Carnivora including Procyonidae several of the Feliformia carnivores. The overwhelming majority of knowledge about disease pathogenesis for these species is biased toward raccoons and concern for disease spread to humans and companion animals. Procyonids and feliform carnivores are ubiquitous in their environments and share habitat and environmental resources with other nondomestic and domestic carnivores and humans. As reservoirs for a number of important multispecies or zoonotic pathogens, surveys for pathogens that may be harbored or vectored by several of the species in this chapter, for example, raccoons (e.g., canine distemper virus, rabies, and leptospirosis) and civets (e.g., SARS coronavirus), have been active areas of investigation. Unfortunately, less research has focused on the potential effects of these pathogens on their hosts.

Metastatic Liposarcoma in a South African Fur Seal (Arctocephalus pusillus)

A 14-year-old female South African fur seal (Arctocephalus pusillus) was presented with a large skin mass on the right shoulder. At necropsy examination, multiple white nodules were found in the lungs, liver, spleen and right axillary lymph nodes. Histologically, the skin mass was composed of round to polygonal neoplastic cells with round to oval nuclei and variably sized cytoplasmic vacuoles. Cellular and nuclear atypia were prominent. Immunohistochemically, the neoplastic cells expressed vimentin, but not cytokeratins, S100 protein, adipophilin or desmin. The cytoplasmic lipid droplets stained positively with oil red O. Metastasis was seen in the lungs, liver, spleen and right axillary lymph nodes, with similar morphological features to the skin mass. Based on these findings, a diagnosis of a pleomorphic liposarcoma with systemic metastasis was made. No previous reports of metastatic liposarcomas have been published in marine mammals.

Liposarcoma in animals: literature review and case report in a domestic pig (Sus scrofa)

Liposarcomas are malignant tumors of adipocytes. The current report describes a liposarcoma in a 2.5-year-old, mixed-breed commercial sow that was detected during meat inspection. On gross examination, a firm, whitish, multinodular, 20 cm ×10 cm mass was observed in the perirenal area along with smaller nodules multifocally scattered within the renal parenchyma. Histological examination revealed an anaplastic sarcoma with clear intracytoplasmic lipidic vacuoles that were positive for Sudan black staining. Most of the cells were also positive for S100 and vimentin immunohistochemistry. Based on these results, a diagnosis of a perirenal liposarcoma was established. To the authors' knowledge, no previous reports of liposarcomas in pigs have been published. This report also includes a review of the literature published on animal liposarcomas.

Anaplastic mandibular carcinoma in a meerkat (Suricata suricatta)

An 8-yr-old female slender-tailed meerkat (Suricata suricatta) presented with a necrotic sublingual mass and osteolysis of the mandible. After 1 mo of palliative care, the meerkat was euthanized. The mass was diagnosed histologically as an anaplastic carcinoma with extensive rostral mandibular destruction. Immunohistochemistry for vimentin and cytokeratin was validated in this nontypical species and showed that neoplastic cells expressed both mesenchymal and epithelial characteristics, suggestive of a primitive and poorly differentiated tumor. A review of 150 adult slender-tailed meerkat histopathology reports showed a 2% prevalence of orofacial neoplasia, suggesting that oral neoplasms are uncommon in meerkats.

Hepatocellular carcinoma in captive slender tailed meerkats (Suricata suricatta): 5 cases

Hepatocellular carcinoma was diagnosed in five slender tailed meerkats (Suricata suricatta) housed at the Smithsonian Institution's National Zoological Park between 1980 and 2013. Animals included four females and one male, ranging from 7 to 15 yr of age. Common clinical signs included weight loss and lethargy. Three of the neoplasms originated from the right medial liver lobe and were located adjacent to or partially incorporated in the gall bladder. Three animals had solitary masses, and two animals had multiple hepatic masses; all were characterized by polygonal to round neoplastic hepatocytes arranged in a trabecular pattern with smaller regions of varied solid, adenoid, and rarely peliod cell patterns. Hemorrhage and necrosis often with cystic degeneration was noted in all five cases. There was no evidence of metastatic disease in any of the cases examined.

Intrahepatic cholangiocarcinoma in a captive meerkat (Suricata suricatta)

A 9-yr-old male meerkat (Suricata suricatta) living in captivity, with a history of anorexia, lethargy, and weight loss, was examined postmortem. Physical examination revealed poor body condition, dehydration, and icteric mucous membranes. Macroscopically, white to yellowish, multinodulated masses were found protruding from the liver. These multinodular masses were also observed in all lobes of the lungs and the mediastinal lymph nodes. Microscopic examination revealed tumors with well-circumscribed, atypical proliferating cuboidal to columnar bile duct epithelial layers arranged in solid sheets and papillary patterns. The neoplastic masses were separated by dense fibrous connective tissues and invaded the normal parenchyma. Periodic acid-Schiff-positive material was occasionally found within the lumen of tubuloacinar structures. Immunohistochemical labeling revealed that neoplastic cells were intensely positive for pan-cytokeratin, but negative for vimentin. Based on the macroscopic and microscopic findings, intrahepatic cholangiocarcinoma was diagnosed. This is the first report describing cholangiocarcinoma in a meerkat.

A Rare Case of Multicentric Liposarcoma and Associated Reproductive Aberrations in a Nonpregnant Holstein-Friesian Crossbred Cow

A five-and-a-half-year-old Holstein-Friesian crossbred cow was repeatedly treated for termination of overgestation, but without any success. On laparotomy, the site indicating fetal-like ballottement on transrectal palpation was occupied by three to four separate caseous and lobulated masses with adhered uterine horns in the omentum. Separation of the utero-omental adhesions retrieved normal-sized uterine horns into pelvic cavity. The right ovary was cystic. Ultrasonography detected another growth in the ventral abdominal musculature. Histopathologically, the omental growths suggested a pleomorphic type of liposarcoma. Presence of omental and muscular liposarcoma along with deep uterine-omental adhesions and a cystic ovary makes this paper a unique addition to the literature.