SERIAL CHANGES IN METABOLIC ACID-BASE STATUS IN THREE SPECIES OF ANESTHETIZED CAPTIVE LARGE FELID.

Determination of acid-base status contributes important information about patient health, including for patients under anesthesia. There is a paucity of information about the determinants of acid-base status of large felids managed under anesthesia, and advancement of such knowledge may contribute to patient safety. This study serially monitored the individual metabolic acid-base status of 11 large felids, including lions (Panthera leo), tigers (Panthera tigris), and cheetahs (Acinonyx jubatus), under general anesthesia. We analyzed the contributions of measured strong ions (sodium, chloride, potassium, lactate), weak acids and buffers (albumin, phosphate and bicarbonate), and unmeasured anions to standardized extracellular base excess (SBE). A general linear model assessed for species differences in these parameters, with time since immobilization, SBE, and mean arterial pressure as covariates. By employing a Stewart-based analytical approach, it was possible to separate chloremic and unmeasured anion contributions to metabolic acid base status. This provided a basis for identifying mixed metabolic processes, generating differentials for underlying causes. Using normal acid base parameters for domestic felids, metabolic acidosis was found to be prevalent. Frequent evidence of unmeasured anion accumulation was also found, with unmeasured anions occasionally exceeding 5mmol/L. These findings warrant further inquiry into the drivers and clinical significance of metabolic acidosis and unmeasured anion accumulations in anesthetized large felids, encouraging further anion identity studies to elucidate possible causes. Reference ranges need to be established for acid-base parameters in large felids as a foundation for interpreting more controlled, prospective research into determinants of metabolic acid-base status in these animals under anesthesia.

Toxoplasma gondii Exposure Prevalence in Little Spotted Kiwi (Apteryx owenii).

Toxoplasma gondii has been reported as a cause of morbidity and mortality in New Zealand's native avifauna, including the ground-dwelling Kiwi (Apteryx spp.). To better understand the extent of T. gondii infection in Little Spotted Kiwi (Apteryx owenii), a prevalence survey of kiwi living inside a 200-ha predator-proof mainland ecosanctuary (Zealandia Te Mara a Tane, Wellington, New Zealand) was undertaken. Antibodies to T. gondii were detected by a latex agglutination test (LAT) with a cutoff positive titer of ≥1:64, and T. gondii DNA was detected by PCR. In total, 16/19 (84.2%) birds tested were positive for T. gondii by LAT (10/11), PCR (10/19), or both (4/11). Antibody titers ranged from 1:32 to ≥1:2,048. These results suggest widespread exposure of T. gondii in this population of Little Spotted Kiwi and, in conjunction with earlier reports of toxoplasmosis causing mortality in kiwi, raise important questions as to the effect this parasite may be having on this rare endemic species. Further information on the epidemiology of T. gondii infections within free-living and managed kiwi populations is urgently needed.

Pathology and molecular epidemiology of Mycobacterium pinnipedii tuberculosis in native New Zealand marine mammals.

Mycobacterium pinnipedii causes tuberculosis in a number of pinniped species, and transmission to cattle and humans has been reported. The aims of this study were to: characterize the pathology and prevalence of tuberculosis in New Zealand marine mammals; use molecular diagnostic methods to confirm and type the causal agent; and to explore relationships between type and host characteristics. Tuberculosis was diagnosed in 30 pinnipeds and one cetacean. Most affected pinnipeds had involvement of the pulmonary system, supporting inhalation as the most common route of infection, although ingestion was a possible route in the cetacean. PCR for the RD2 gene confirmed M. pinnipedii as the causal agent in 23/31 (74%) cases (22 using DNA from cultured organisms, and one using DNA from formalin-fixed paraffin-embedded (FFPE) tissue), including the first published report in a cetacean. RD2 PCR results were compared for 22 cases where both cultured organisms and FFPE tissues were available, with successful identification of M. pinnipedii in 7/22 (31.8%). In cases with moderate to large numbers of acid-fast bacilli, RD2 PCR on FFPE tissue provided a rapid, inexpensive method for confirming M. pinnipedii infection without the need for culture. VNTR typing distinguished New Zealand M. pinnipedii isolates from M. pinnipedii isolated from Australian pinnipeds and from common types of M. bovis in New Zealand. Most (16/18) M. pinnipedii isolates from New Zealand sea lions were one of two common VNTR types whereas the cetacean isolate was a type detected previously in New Zealand cattle.