Epidemiology and diagnosis of Mycobacterium tuberculosis in captive Asian elephants (Elephas maximus).

The deaths of two Asian elephants (Elephas maximus) in August 1996 led the United States Department of Agriculture to require the testing and treatment of elephants for tuberculosis. From August 1996 to September 1999. Mycobacterium tuberculosis infection was confirmed by culture in 12 of 118 elephants in six herds. Eight diagnoses were made antemortem on the basis of isolation of M. tuberculosis by culture of trunk wash samples; the remainder (including the initial two) were diagnosed postmortem. We present the case histories, epidemiologic characteristics, diagnostic test results, and therapeutic plans from these six herds. The intradermal tuberculin test, enzyme-linked immunosorbent assay serology, the blood tuberculosis test, and nucleic acid amplification and culture are compared as methods to diagnose M. tuberculosis infection in elephants.

Concepts of veterinary practice in wild mammals.

At the beginning of this article, we described the challenge faced by wildlife veterinarians in extrapolating treatment regimens and finding data bases of physiologic variables with which to assess health or depth of anesthesia in wild mammals. For example, we might wish to administer injectable ivermectin to a 75-kg deer and a 75-g squirrel for treatment of intestinal nematodes. An effective dose of ivermectin for the 75-kg deer is 0.2 mg/kg SC, and for the 75 g (0.075 kg) squirrel is 1.3 mg/kg SC. Given the squirrel dose (1.3 mg/kg), the deer could be made very ill or even killed by the treatment; whereas given the deer dose (0.2 mg/kg), the squirrel would not receive enough ivermectin to achieve a therapeutic level. This is the reason for allometric scaling of drug doses. Scaling doses allometrically is an arithmetic procedure that is more precise than trying to extrapolate doses between animals of diverse body sizes (such as the ermine and the wolverine) and between species that have different core body temperature set points (such as marsupial and placental mammals). For many years, in human and veterinary medicine, practitioners have allometrically scaled doses of potentially toxic chemotherapeutic agents using either (1) mg or micrograms drug/M2 body surface area or (2) mg or micrograms of drug/SMEC. Allometric calculations give results that are much more predictable and take into consideration substantial differences in body size and core body temperature.

Audit of nutritional support provided to surgical patients by a nutrition team.

An audit was carried out over a 24 month period to assess the practice, safety and efficacy of nutritional support provided to surgical patients by a designated team. 135 patients received nutritional support: 51% were fed parenterally, 32% enterally and 17% via combined nutritional support. The duration of feeding ranged from 1-177 days with 23% being supported for < 7 days. The line infection rate for patients receiving intravenous nutrition was 6.5%. Nutritional outcome was assessed using weight, anthropometry and bioelectrical impedance analysis. Pre-and post-feeding results were available for 67% of patients. These patients were classified as either oedematous (n = 21), normally nourished (n = 23) or nutritionally depleted (n = 46). Overall, the oedematous patients lost water, the protein status of the normally nourished group deteriorated slightly and the nutritional status of the nutritionally depleted patients was maintained. Audit is a valuable means of defining the efficacy of a nutrition support service and has identified areas which require review.

A prospective study of bronchial hyperresponsiveness and respiratory symptoms in a population of Australian schoolchildren.

To examine the relationship between bronchial hyperresponsiveness (BHR) and respiratory symptoms associated with asthma, we studied a sample of 380 schoolchildren on three occasions at 2-yr intervals. The age of the children at the first study was 8-10 yr. Respiratory symptoms history was assessed by questionnaire, BHR was measured by a histamine inhalation test and atopy was assessed by skin-prick tests to 13 allergens. The cumulative prevalence of BHR in this sample was 27%. The severity of BHR was categorized as severe, moderate, mild or slight. The distribution of severe, moderate and mild BHR was similar at each of the studies. At the third study, when the children were aged 12-14 yr, the prevalence of slight BHR decreased. Children with severe or moderate BHR at age 8-10 yr were atopic, reported current symptoms during the 4 yr of the study and had a high prevalence of severe or moderate BHR in later studies. In this group, 87% of children had current respiratory symptoms and 73% were using asthma medication at age 12-14 yr. In children with mild or slight BHR when first studied, the prevalence of atopy, continuing respiratory symptoms and medication use was much lower. We conclude that severe or moderate BHR is an important risk factor for ongoing morbidity and that comparisons of the prevalence of this severity of BHR in populations may be more informative than comparisons of BHR defined by present criteria.

Anesthesia for rabbits.

The author discusses techniques of anesthesia in rabbits as well as characteristics of rabbits that may influence the administration and effectiveness of anesthesia.

Anesthesia for fish.

In fish, the most common purpose of anesthesia is to facilitate handling for physical examination and diagnostic sampling. Fish may also be transported to new locations more safely having been sedated. The author describes techniques of anesthesia in fish as well as the biologic characteristics of fish.

House dust mites and skin tests in different Australian localities.

Dermatophagoides mite concentrations in household dust have been measured in three Australian towns with contrasting geographical features, climate, and degree of urbanisation. Mite allergen skin tests on school children living in these areas showed that the prevalence of positive reactions varied with mite concentrations. In Belmont, D. farinae as well as D. pteronyssinus were present in some of the dust samples. Skin test weals were larger in Busselton than in either Wagga Wagga or Belmont. The importance and practical implications of these findings are discussed.

Prevalence of bronchial hyperresponsiveness in children: the relationship between asthma and skin reactivity to allergens in two communities.

A coastal population mainly reactive to house dust mite was compared with an inland population mainly reactive to other allergens to investigate whether exposure to house dust mite plays a part in initiating childhood asthma. Respiratory symptoms, asthma, bronchial hyperresponsiveness, hay fever and atopy were all more common in the dry inland area than in the humid coastal area. In both areas 38% of children were atopic. Coastal children had more skin reactivity to house dust mites and inland children were more reactive to grass pollen extracts. The findings suggest that the clinical presentation of asthma may be related more to the total burden of aeroallergens than to exposure to a particular allergen.

Elastin accumulation in the chick aorta: effect of 6-hydroxydopamine and deoxycorticosterone acetate.

The net accumulation of aorta elastin in the chick was estimated from day 1 to 14, post-hatching. Increased elastin accumulation was coincident with the elevation in blood pressure observed for this period. Further deoxycorticosterone acetate plus dietary NaCl also caused stimulation of protein synthesis in aorta. In contrast, aorta protein synthesis and net elastin accumulation appeared to be decreased in chicks given 6-hydroxydopamine.

The effect of thyroid hormone administration upon survival in patients with differentiated thyroid carcinoma.

Seven hundred sixty-one patients with operable differentiated thyroid carcinoma were treated between 1931 and 1970. Median follow-up time was 18 years and ranged from 5 to 40 years. Sixty-three percent of the patients were followed more than 15 years, and 46% were followed more than 20 years. Because resections usually spared sufficient thyroid tissue for homeostasis, thyroid hormone was not routinely prescribed after operations performed before 1960. Altogether 244 patients with papillary carcinoma and 76 patients with follicular carcinoma received thyroid hormone, while 296 patients with papillary carcinoma and 45 patients with follicular carcinoma did not receive thyroid hormone after operation. With papillary carcinoma, 14% of men greater than 40 and women greater than 50 years of age (high risk) but only 2% of men less than or equal to 40 years of age and women less than or equal to 50 years of age (low risk) died of disease (P 0.0001). Twenty-six percent of high-risk but only 4% of patients with low-risk follicular cancer died (P 0.0001). However, there was no statistically significant improvement in survival times with use of thyroid hormone when patients were categorized by risk group and pathology. These data support the importance of age and sex in previously described risk groups; these factors supersede the effects of adjuvant treatment. This absence of effect on survival times calls into question current recommendations for routine use of thyroid hormone after surgical therapy. Conceptually, such absence of adjunctive hormone effect on survival time after operation is similar to hormonal effects in other endocrine cancers, which may nevertheless provide good palliation in some cases.