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Leukemia and lymphoma account for more than 60% of deaths in captive koalas ( Phascolarctos cinereus ) in northeastern Australia. Although the endogenizing gammaretrovirus koala endogenous retrovirus (KoRV) was isolated from these koalas, KoRV has not been definitively associated with leukemogenesis. We performed KoRV screening in koalas from the San Diego Zoo, maintained for more than 45 y with very limited outbreeding, and the Los Angeles Zoo, maintained by continuously assimilating captive-born Australian koalas. San Diego Zoo koalas are currently free of malignant neoplasias and were infected with only endogenous KoRV, which we now term subtype “KoRV-A,” whereas Los Angeles Zoo koalas with lymphomas/leukemias are infected in addition to KoRV-A by a unique KoRV we term subtype “KoRV-B.” KoRV-B is most divergent in the envelope protein and uses a host receptor distinct from KoRV-A. KoRV-B also has duplicated enhancer regions in the LTR associated with increased pathology in gammaretroviruses. Whereas KoRV-A uses the sodium-dependent phosphate transporter 1 (PiT1) as a receptor, KoRV-B employs a different receptor, the thiamine transporter 1 (THTR1), to infect cells. KoRV-B is transmitted from dam to offspring through de novo infection, rather than via genetic inheritance like KoRV-A. Detection of KoRV-B in native Australian koalas should provide a history, and a mode for remediation, of leukemia/lymphoma currently endemic in this population.

Mycoplasma alligatoris was the suspected etiology of an epidemic of acute multisystemic inflammatory disease which emerged in captive American alligators (Alligator mississippiensis) in Florida (USA) in 1995. In an experimental inoculation study conducted from April through October 1999, 18 alligators were inoculated with 10 2 , 10 4 , or 10 6 colony forming units (CFU) of M. alligatoris by instillation into the glottis. As early as 1 wk post-inoculation (PI), mycoplasma were cultured from blood of three of six alligators inoculated with 10 6 CFU. Two of those died and the third was euthanatized within 4 wk PI. Necropsy gross findings included fibrinous polyserositis and polyarthritis. Histopathologic changes in affected individuals included pulmonary edema, interstitial pneumonia, pericarditis, myocarditis, meningitis, and synovitis. Mycoplasma were cultured quantitatively in high numbers from trachea, lung, coelomic cavity, liver, spleen, interior of pericardial sac, heart, blood, brain, and limb joints. In alligators inoculated with 10 6 CFU, heterophilia and moderate hyperglycemia peaked about 4 wk PI, and seroconversion occurred by 6 to 8 wk PI. Necropsy gross and histologic findings were generally unremarkable for the surviving alligators inoculated with 10 6 CFU, alligators inoculated with 10 2 or 10 4 CFU, and four uninoculated control alligators. Mycoplasma were not cultured at any time point from those alligators. The findings confirm that M. alligatoris can cause fulminant inflammatory disease and rapid death of alligators.

Colorectal cancer is the second most common cause of death from malignant disease in England and Wales

Recent evidence suggests that the production of colorectal carcinogens is facilitated when the pH of the colonic contents is alkaline. It follows that the colonic intraluminal pH of patients with colorectal neoplasms should be higher than in normal subjects. Gastrointestinal pH has been measured in 30 patients with colorectal cancer and 37 patients with benign colorectal adenomas (using a pH sensitive radiotelemetry capsule). These values have been compared with those recorded in 66 normal subjects. No differences in gastrointestinal pH were found and the results did not support the hypothesis that colonic pH plays a role in the aetiology of colorectal neoplasia.

Summary An established chemical faecal occult blood test (Haemoccult prepared without rehydration) has been compared with a new immunological test (Hemeselect) in patients referred for investigation of lower gastro-intestinal symptoms.Hemeselect was shown to have a higher sensitivity for colorectal carcinoma (94.0% compared with 58.0%), the greatest difference in sensitivity between the two tests being for rectal cancers. Similarly Hemeselect was more sensitive than Haemoccult for colorectal adenomas (66.6% vs 33.3%), and for inflammatory bowel disease (88.9% vs 33.3%).However the enhanced sensitivity of Hemeselect for colorectal neoplasia and inflammatory bowel disease was accompanied by a significant increase in the overall rate of positive reactions (32.8% of patients had a positive Hemeselect reaction compared with 14.8% who had a positive Haemoccult test), and a reduction in specificity (84.1% for Hemeselect vs 96.0% for Haemoccult).Hemeselect is a more sensitive indicator of colorectal neoplasia in symptomatic subjects, trials of its use as a screening test for asymptomatic neoplasia appear justified.Faecal occult blood tests are potentially useful in the preliminary assessment of subjects with symptoms of colorectal disease (Leicester et al., 1983) and also for mass population screening for asymptomatic colorectal neoplasia. The test commonly used for screening, Haemoccult (Rohm Pharma) has an estimated sensitivity in the range 50-65% for asymptomatic cancers (Kewenter et al., 1988;Kronborg et al., 1989;Hardcastle et al., 1989) and has been noted to be particularly insensitive for rectal and caecal cancers, missing over 50% of malignancies at these sites (Kronborg et al., 1989;Hardcastle et al., 1989). In contrast over 70% of sigmoid cancers are detected. One of the proposed mechanisms for this discrepancy is that Haemoccult, which is essentially a test for the Haematin moiety of Haemoglobin, relies on an optimum degree of Haemoglobin degradation which is most commonly achieved by blood loss from sigmoid cancers.Immunological tests, not dependent on Haematin, should reliably detect bleeding from rectal cancers, although they may also be affected by excessive degradation of blood from caecal cancers. Hemeselect (Smith-Kline Diagnostics) utilises fixed chicken erythrocytes that have coated with an antihuman haemoglobin antibody. Faecal matter is smeared onto filter paper by the patients. Small discs of the paper are then used to obtain a dilute faecal solution to which the coated chicken erythrocytes are added, erythrocyte agglutination occurs in the presence of haemoglobin in the faecal solution.The The sensitivity of both tests was independent of tumour stage (Table II).A total of 26 adenomatous polyps were diagnosed in 21 patients (Table III) Nine patients were shown to have an inflammatory condition affecting the colon or rectum (Table IV), of these three (33.39%) had a positive Haemoccult test and eight (88.9%) a positive Hemeselect test (Fisher's test, P = 0.02).The specificity for neoplasia or inf...

Despite being a charismatic and well-known species, the social system of the koala (Phascolarctos cinereus—the only extant member of the family Phascolarctidae) is poorly known and much of the koala’s sociality and mating behaviors remain un-quantified. We evaluated these using proximity logging-GPS enabled tracking collars on wild koalas and discuss their implications for the mating system of this species. The frequency and duration of male-female encounters increased during the breeding season, with male-male encounters quite uncommon, suggesting little direct mating competition. By comparison, female-female interactions were very common across both seasons. Body mass of males was not correlated with their interactions with females during the breeding season, although male size is associated with a variety of acoustic parameters indicating individuality. We hypothesise that vocal advertising reduces the likelihood of male-male encounters in the breeding season while increasing the rate of male-female encounters. We suggest that male mating-season bellows function to reduce physical confrontations with other males allowing them to space themselves apart, while, at the same time, attracting females. We conclude that indirect male-male competition, female mate choice, and possibly female competition, mediate sexual selection in koalas.