Abstract

During a routine blood collection of the Zoomarine grey seals in February 2000, a 10-year-old female was found to be markedly anemic, confirmed by a recheck a few days later. Although the animal behaved normally, empirical treatment was started due to the seriousness of the results compared to the normal results of the other animals.

The remaining blood parameters were within the normal range for grey seals.

The first regimens of treatment consisted of general anti-anemic drugs such as iron, folic acid and vitamin B12, as well as Yunnan Baiyio, and Clindamycin, in the event that a chronic infection could have depleted her white blood cells (WBC) and yielded this anemia. The differential diagnoses considered were: profound blood loss through a recent wound, long term administration of antibiotics or anti-fungals for the treatment of chronic bite wounds, chronic bleeding from the urinary or digestive tract, the possible presence of hemolytic parasites, a hemolytic toxin or hyperoestrogenism yielding medulla aplasia.

Hyperoestrogenism yielding medulla aplasia was confirmed by 1) a bone marrow biopsy from her right hip revealing a hypoplastic non-regenerative anemia; 2) estradiol results as high as 485.1 pg/ml, whereas estradiol results from the other seals in the collection ranged from 6.33 pg/ml to 43.9 pg/ml; 3) ultrasound imaging of the ovaries that showed the presence of several cysts.

The anemia improved slowly with the supportive treatment. It took 6 months to reach normal blood values. However, as soon as treatment was discontinued, the blood values dropped dramatically again. An ovariectomy by laparoscopy was planned in an attempt to save the animal. Sam Dover performed the laparoscopy on October 22, 2003. The animal had become extremely thin, weighing 74 kg at the time of the surgery (optimal weight range = 120 to 130 kg). It took just over 4 hours to perform the surgery. Maintenance anaesthesia was achieved with Isoflurane at a rate between 0.8 and 1.0%. The animal was ventilated with 3 liters of oxygen every 3 minutes.

Two polycystic ovaries were retrieved. Five hepatic biopsies and 2 skin biopsies were obtained for the purpose of evaluating the effect of long term iron supplementation, as the skin showed yellow discoloration. The animal woke up 10 minutes after the end of the anesthesia. She recovered well and had a good appetite in the days to follow.

At the time of this abstract her blood values were slowly rising, and she was slowly gaining weight. The histopathological analysis revealed the following: ovaries with cystic follicles, the presence of yellow-brown granulation in the cytoplasm of the hepatocytes, indicative of hemosiderin and a lymphocytic dermatitis. The proposed course of action, providing the animal reaches an optimum weight and maintains normal blood values, will be to discontinue the supportive medication one by one and possibly perform another bone marrow biopsy at a later date.

Acknowledgements

The authors would like to thank the staff and management of Zoomarine for their assistance and opportunity to perform this procedure.