Fatal Chryseobacterium indologenes infection in a captive red‐shanked Douc langur (Pygathrix nemaeus)

Abstract

A captive born 1-year-4-month-old male Douc langur (Pygathrix nemaeus) presented acutely for reduced appetite and lethargy. It had no prior medical conditions but its dam had died from melioidosis 4 months prior. Its condition deteriorated quickly within 24 h and it was anaesthetized for a full veterinary assessment.The animal was moderately thin (2.9 kg) and blood work showed low white cell counts, leukocytes 1.48 × 10 9 cells/L, reference interval [RI] 5.1-16.8, 1 with neutrophils 0.87 × 10 9 cells/L, lymphocytes 0.58 × 10 9 cells/L and monocytes at 0.02 × 10 9 cells/L. Platelets were reduced (50 × 10 9 cells/L). Plasma biochemistry showed reduced glucose (0.95 mmol/L, RI 4.23-10.71) and elevated ALT (285 U/L). Ultrasound examination showed that the liver was mildly enlarged with rounded margins. The parenchyma was mildly hyperechoic with diffuse small, irregular hyperechoic foci. An irregular hypoechoic lesion measuring 0.98 cm × 0.50 cm was seen on the diaphragmatic surface of the right liver lobe (Figure 1A).The animal was started on treatment in hospital for suspected melioidosis due to its history of potential exposure, as melioidosis is endemic in Singapore Zoo. 2 Intravenous fluid therapy was initiated with a solution of 500 mL lactated Ringer's Solution supplemented with 40 mL 50% glucose, 10 mL 7.45% potassium chloride and 1 mL vitamin B Complex (3 mL/kg/h). An antibiotic combination of ceftazidime (50 mg/kg IV BID) and enrofloxacin (5 mg/kg IV SID) was started. A single anti-inflammatory dose of dexamethasone (0.12 mg/kg IV) was given. Supportive therapy included metoclopramide (0.5 mg/kg IV BID), buprenorphine (0.02 mg/kg IV BID) and Ornipural® (0.5 mL IV EOD). Repeated haematology 12 h later showed anaemia (PCV 23%, reference range 31.8-52.8%) and worsening thrombocytopenia (14 × 10 9 cells/L). Unfortunately, the animal did not respond to treatment and died 24 h after treatment started.A post-mortem examination was conducted within 1 h of death.