Domestic poultry are important natural hosts of Mycobacterium avium (MAC), especially in the traditional poultry management system in the tropics. Qualitative and quantitative studies on a total of 95 chickens from three agro-climatic areas in Ethiopia were examined for avian mycobacteriosis through postmortem examinations and tissue staining (haematoxylin & eosin and acid-fast staining). The mycobacteria species were isolated and identified by using mycobacteriologic culture and experimental infection for virulence assessment. Five of the 95 examined chickens (5.3%) had gross tuberculous lesions in different visceral organs. On histopathologic examination, the lesions showed granuloma with typical Langhan’s giant cells in which acid-fast bacilli were shown by acid-fast stain. The culture on pyruvate-enriched Lowenstein-Jensen slants revealed growth of colonies on samples from 6 (6.3%) of the 95 chickens. Experimental infection with the strains from culture resulted in death of 10 (83.3%) of 12 inoculated chickens 56 to 110 days after inoculation, indicating that the isolates may be virulent strains of MAC. On postmortem examination, the experimentally infected chickens showed similar tuberculous lesions to natural infection that was confined at the site of injection, on the liver, spleen and (in two subjects) small intestine. The inoculated organisms were recovered from the respective organs. Therefore, this study showed that a virulent strain of MAC infects domestic chicken in Ethiopia.

A cross-sectional study to determine individual animal prevalence of bovine tuberculosis (BTB) was conducted on 1171 dairy cattle in 12 randomly selected dairy farms in Ethiopia between January 1999 and May 2001 using comparative intradermal tuberculin (CIT) test and bacteriologic study through milk culturing. An overall individual animal prevalence of 46.8% (548 of 1171 animals) and a herd prevalence of 91.7% (11 of 12 farms) were recorded in 12 dairy farms by the CIT test. There were significant (P <0.0001) differences in individual prevalence between farms and breeds (pure Holstein and their crosses with Zebu). There was positive correlation (r = 0.41) between herd size and prevalence of bovine tuberculosis. Furthermore, a negative linear association (R2 = 0.24) was found between mean score of management of the farm and prevalence, indicating that the prevalence of bovine tuberculosis could be improved by sanitary measures. Breed and management affected the prevalence of BTB (R2 = 0.30) as confounding variables. Mycobacterium bovis was isolated from the milk of 13.3% (4 of 30) reactor cows. The widespread occurrence of BTB in the study farms and isolation of M. bovis from the milk of reactor cows signify its economic importance and potential risk to public health. Generalization and improved use of milk pasteurization within all dairy subsectors is recommended, and this would affect the competitiveness of the dairy sector in Ethiopia.

A cross-sectional study was conducted between December 2001 and April 2002 on 94 households and 763 (188 indigenous and 575 crossbred) cattle to determine the prevalence of bovine tuberculosis (BTB) and assess its public health implications in smallholder farms in Wuchale-Jida District, Central Ethiopia. Cluster sampling, single intradermal tuberculin (SIDT) and comparative intradermal tuberculin (CIDT) tests, a questionnaire, and mycobacteriology were used. Based on the CIDT test, herd and individual animal prevalences of BTB were 42.6% and 7.9%, respectively. The individual animal prevalence was significantly affected by herd size (P<0.01), age (P<0.0001) and body condition (P<0.05). Among the interviewed households, 24.5% (23 of 94) had experienced at least one human tuberculosis case in the family. Of these families, 43.5% (10 of 23) had reactor cattle. Nevertheless, no statistically significant association (P>0.05) was observed between reactor cattle and human tuberculosis cases in households. The habit of milk and meat consumption was affected by occupation (P<0.0001) and location of household residence (P<0.001). Although the level of education influenced the habit of milk consumption (P<0.05), it did not impact the habit of meat consumption (P>0.05). Less than half (38.3%; 36 of 94) of the respondents knew about BTB, and only 30.8% (29/94) of the respondents were conscious of its transmission from cattle to humans. Secondary data analysis from Muka-Turri clinic indicated that 85.6% of the human tuberculosis cases were from rural parts of the district. Although the BTB prevalence seems low, its potential risk to public health was important based on food consumption, poor sanitary measures, and the lack of understanding about its zoonosis.

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peer reviewed | OBJECTIVE: To compare sensitivity of the impulse oscillometry system (IOS) with that of the conventional reference technique (CRT; ie, esophageal balloon method) for pulmonary function testing in horses. ANIMALS: 10 horses (4 healthy; 6 with recurrent airway obstruction [heaves] in remission). PROCEDURE: Healthy horses (group-A horses) and heaves-affected horses (group-B horses) were housed in a controlled environment. At each step of a methacholine bronchoprovocation test, threshold concentration (TC(2SD); results in a 2-fold increase in SD of a value) and sensitivity index (SI) were determined for respiratory tract system resistance (R(rs)) and respiratory tract system reactance (X(rs)) at 5 to 20 Hz by use of IOS and for total pulmonary resistance (RL) and dynamic lung compliance (C(dyn)), by use of CRT. RESULTS: Bronchoconstriction resulted in an increase in R(rs) at 5 Hz (R(5Hz)) and a decrease in X(rs) at all frequencies. Most sensitive parameters were X(rs) at 5 Hz (X(5Hz)), R(5Hz), and R(5Hz):R(10Hz) ratio; RL and the provocation concentration of methacholine resulting in a 35% decrease in dynamic compliance (PC(35)C(dyn)) were significantly less sensitive than these IOS parameters. The TC(2SD) for X(rs) at 5 and 10 Hz was significantly lower in group-B horses, compared with group-A horses. The lowest TC(2SD) was obtained for X(5Hz) in group-B horses and R(5Hz) in group-A horses. CONCLUSIONS AND CLINICAL RELEVANCE: In contrast to CRT parameters, IOS parameters were significantly more sensitive for testing pulmonary function.The IOS provides a practical and noninvasive pulmonary function test that may be useful in assessing subclinical changes in horses.

Objective-To determine the presence of adenosine receptor subtypes A1 and A2a in equine forebrain tissues and to characterize the interactions of caffeine and its metabolites with adenosine receptors in the CNS of horses. Sample Population-Brain tissue specimens obtained during necropsy from 5 adult male research Procedures-Membrane-enriched homogenates from cerebral cortex and striatum were evaluated by radioligand binding assays with the A1-selective ligand [3H]DPCPX and the A2a-selective ligand [3H]ZM241385. Functional responses to adenosine receptor agonists and antagonists were determined by a nucleotide exchange assay using [35S]-guanosine 5'-(γ-thio) triphosphate [35S]GTPγS). Results-Saturable high affinity [3H]DPCPX binding (A1) sites were detected in cerebral cortex and striatum, whereas high-affinity [3H]ZM241385 binding (A2a) sites were detected only in striatum. Caffeine and related methylxanthines had similar binding affinities at A1 and A2a sites with rank orders of drug binding affinities (theophylline > paraxanthine ≥ caffeine >> theobromine) similar to other species. [35S]GTPγS exchange revealed that caffeine and its metabolites act as pure adenosine receptor antagonists at concentrations that correspond to A1 and A2a receptor binding affinities. Conclusions and Clinical Relevance-Results of our study affirm the presence of guanine nucleotide binding protein linked adenosine receptors (ie, high-affinity A1 and A2a adenosine receptors) in equine forebrain tissues and reveal the antagonistic actions by caffeine and several biologically active caffeine metabolites. Antagonism of adenosine actions in the equine CNS by these stimulants may be responsible for some central actions of methylxanthine drugs, including motor stimulation and enhanced racing performance.

Objective-To compare effects of electroacupuncture and butorphanol on hemodynamic and respiratory variables and rectal analgesia in mares after controlled rectal distention. Animals-8 healthy mares. Procedure-Each horse received saline (0.9% NaCl) solution (0.01 mL/kg, IV; control treatment), butorphanol tartrate (0.1 mg/kg, IV), or 2 hours of electroacupuncture (EA) at acupoints Bladder 21, 25, and 27 on both sides of the vertebral column, Bai hui, and Stomach 36 (right side only). Order of treatments in each mare was randomized. At least 7 days elapsed between treatments. A balloon was inserted in the rectum of each mare, and controlled distention of the balloon (pressures of ≤ 220 mm Hg) was used to measure nociceptive rectal pain threshold. Rectal temperature and cardiovascular and respiratory variables were measured before (baseline) and 5, 15, 30, 60, 90, and 120 minutes after onset of each treatment. Results-Butorphanol produced greater increases in rectal pain threshold, compared with EA (mean +/- SD, 214 +/- 24 vs 174 +/- 35 mm Hg of balloon pressure). Electroacupuncture produced minimal cardiovascular and respiratory changes. Although clinically not important, butorphanol produced moderate significant increases in heart and respiratory rates, arterial blood pressure, and rectal temperature and decreases in arterial oxygen tension. Arterial pH, carbon dioxide tension, bicarbonate concentrations, base excess, Hct, and concentration of total solids were not significantly different from baseline values after EA, butorphanol, and control treatments. Conclusions and Clinical Relevance-Electroacupuncture and butorphanol (0.1 mg/kg, IV) may provide useful rectal analgesia in horses.

Objective-To use an amplified ELISA technique to document the presence and quantify the concentration of the house dust mite allergen, Der f 1, in skin and coat dust samples collected from dogs. Animals-29 pet dogs of various breeds. Procedure-Dogs were weighed, and body surface area in square meters was determined. Skin and coat dust samples were obtained by vacuuming dogs. Collected dust was analyzed by use of standard and amplified ELISA techniques. Results-By use of the standard ELISA technique, Der f 1 was detected in skin and coat dust samples from 6 of 29 (21%) dogs. Mean concentration of Der f 1 in the 6 samples with positive assay results was 16.16 ng/mL (range, 5.61 to 31.24 ng/mL). Samples with negative assay results were retested for dust mite allergen by use of an amplified ELISA technique; an additional 14 dogs had positive assay results. Mean concentration of allergen was 0.36 ng/mL (range, 0.19 to 2.20 ng/mL). Combining both techniques, 20 of 29 (69%) dogs had positive assay results for Der f 1. Conclusions and Clinical Relevance-Results of our study indicate that house dust mite allergens are present on the skin and in the coat of dogs, and this source of allergen may act as a reservoir for allergen exposure in hypersensitive dogs. Use of an amplified ELISA technique to determine environmental concentrations of house dust mite allergens in homes and on dogs will help to identify the relationship between immunologic findings and environmental exposures in dogs with atopic dermatitis.

Objective-To quantitate dose- and time-related magnitudes of interactive effects of morphine (MOR) and isoflurane (ISO) in horses and to characterize pharmacokinetics of MOR in plasma and the ventilatory response to MOR during administration of ISO. Animals-6 adult horses. Procedure-Horses were anesthetized 3 times to determine the minimum alveolar concentration (MAC) of ISO in O2 and then to characterize the change in anesthetic requirement as defined by the alteration in ISO MAC following IV administration of saline (0.9% NaCl) solution and 2 doses of MOR (low dose, 0.25 mg/kg; high dose, 2.0 mg/kg). Arterial blood samples were obtained before and after MOR and analyzed. Results-Mean +/- SD baseline ISO MAC was 1.43 +/- 0.06%. The ISO MAC did not change with time after administration of saline solution. Effects of MOR on ISO MAC varied. Maximal change in MAC ranged from –20.2 to +28.3% and -18.9 to +56.2% after low and high doses of MOR, respectively. Typical half-life of MOR in plasma was 40 to 60 minutes and related to dose. Mean PaCO2 increased from 70 mm Hg before MOR to 88 to 102 mm Hg for 30 to 240 minutes after the high dose of MOR. Recovery from anesthesia after administration of the high dose of MOR was considered undesirable and dangerous. Conclusions and Clinical Relevance-Our results do not support routine clinical use of MOR administered IV at dosages of 0.25 or 2.0 mg/kg as an adjuvant to anesthesia in horses administered ISO.