Tono-Pen XL calibration curves for cats, cows and sheep

The objective of this study was to provide calibration curves for correcting intraocular pressure (IOP) measurements obtained using the Tono-Pen XL tonometer in cats, cows and sheep. Twelve eyes from 9 cats, 13 eyes from 7 cows, 10 eyes from 5 sheep were used. The anterior chamber of the eye was cannulated in vivo, in situ (immediately post mortem) or ex vivo with a fine needle and IOP was varied from 10 to 90 mmHg in steps of 10 mmHg by adjusting the height of a saline reservoir connected to the needle. For each pressure setting, several readings of IOP were made using the tonometer. The relationship between Tono-Pen reading and manometer setting was linear over the full range of measurement. However, the slope of the data regression line deviated significantly from 1 and indicated that the instrument systematically underestimated IOP. For cats the average slope was 0.62 and for cows and sheep it was 0.72 and 0.69, respectively. For the latter animals, the regression line also had a nonzero intercept of approximately 4.5 mmHg. Similar results were obtained from in vivo and ex vivo eyes and with different Tono-Pen XL tonometers. Although developed for use on humans, the Tono-Pen XL can provide reproducible and accurate measurement of IOP in cats, cows and sheep when suitably calibrated by manometry. The calibration curves provided here, and by implication those reported for other animals using this tonometer, differ in slope from those measured with earlier models of the Tono-Pen. The reproducibility of the curves we obtained implies that they can be used to correct IOP readings from the Tono-Pen XL when manometry is not possible.     

Evaluation of the efficacy of a commercial diet in the dissolution of feline struvite bladder uroliths

Clinical signs of struvite urolithiasis resolved in an average of 19 days in cats fed either a canned or dry urine-acidifying, magnesium-restricted diet, and stones completely dissolved in 31 of 39 cats in an average of 30 days. Stones were surgically removed from five cats, and analysis revealed that these stones were not composed of struvite. The results of this study strongly suggest that the diet will dissolve naturally occurring feline struvite bladder uroliths.     

Identification of new morphological and life-cycle stages of Cochlosoma anatis and experimental transmission using pseudocyst

Cochlosoma anatis is a flagellated intestinal parasite that infects a variety of avian species. C. anatis infections have been associated with decreased weight gain and increased morbidity and mortality. Conditions favoring the growth of this organism in birds are current pathogenic intestinal infections and/or young age. There is little data describing the life cycle of this parasite. In this study, electron microscopy images are presented that document longitudinal binary fission of the trophozoite stage and outline the events of pseudocyst formation, which includes a rounding stage. Evidence provided here indicates that the pseudocyst stage may be a mechanism for transmission of this organism. The observations reported here provide additional evidence of homology between Cochlosoma and members of the trichomonad order.     

Disease constraints for utilization of the African buffalo (Syncerus caffer) on game ranches in Zambia

Eco-tourism depending on wildlife is becoming increasingly profitable and landowners are beginning to favor game farming and ecotourism. In these areas, large-scale translocation of wildlife involves a diversity of species and large populations. The African buffalo (Syncerus caffer) is one of the major tourist attractions in Zambia. It accounts for 8.7% and 12.4% of the total animal species hunted in the Game Management Areas and the total hunting revenue earned in Zambia, respectively. It is ecologically an important animal species essential for the purpose of habitat control and facilitating the provision of suitable grazing pastures. However, the rearing of the African buffalo on game ranches has been hampered by its carrier state of the Southern Africa Terroritory (SAT) serotypes of foot and mouth disease virus (FMD). The African buffalo is also known to be a carrier of Theileria parva lawrencei, the causative agent of corridor disease (CD) that continues to have devastating effects on the livestock industry in Zambia. In addition, the importation of buffaloes from countries with populations endemic to bovine tuberculosis is highly restricted. Veterinary regulations in Zambia, strongly advocate against the translocation of buffaloes from protected areas to private ranches for disease control purposes thereby mounting a considerable constraint on the economic and ecological viability of the industry. It is hoped that this review will motivate the relevant government authorities in exploiting ways in which this animal species play a central role in eco-tourism.     

Cloning and radiation hybrid mapping of bovine toll-like receptor-4 (TLR-4) signaling molecules

Toll-like receptor (TLR)-4 is a transmembrane receptor for lipopolysaccharide, a highly pro-inflammatory component of the outer membrane of Gram-negative bacteria. To date, molecules of the TLR-4 signaling pathway have not been well characterized in cattle. The goal of this study was to clone and sequence the full-length coding regions of bovine genes involved in TLR-4 signaling including CASP8, IRAK1, LY96 (MD-2), TICAM2, TIRAP, TOLLIP and TRAF 6 and to position these genes, as well as MyD88 and TICAM1, on the bovine genome using radiation hybrid mapping. Results of this work indicate differences with a previously published bovine sequence for LY96 and a predicted sequence in the GenBank database for TIRAP based on the most recent assembly of the bovine genome. In addition, discrepancies between actual and predicted chromosomal map positions based on the Btau_2.0 genome assembly release were identified, although map positions were consistent with predicted locations based on the current bovine-human comparative map. Alignment of the bovine amino acid sequences with human and murine sequences showed a broad range in conservation, from 52 to 93%. Overall, this work should assist in the assembly and annotation of the bovine genome sequence, the identification of variations in genes critically involved in host innate immunity, and facilitate the study of TLR-4 signaling pathways in cattle.     

Tuberculosis in cattle: strategic planning for the future

In the later stages of eradication of tuberculosis in cattle there is a need to take account of the fact that Mycobacterium bovis infection in cattle presents, not as cases of clinical disease but most commonly as apparently healthy animals showing an immunological response to tuberculin. This is an entirely different scenario to that seen when national eradication programmes were first devised, at a time when the protection of public health rather than animal health was the prime motivation. In countries with active programmes to eradicate bovine tuberculosis, it is critical for the programme's success that account is taken of this redefinition of tuberculosis, side by side with changes in modern animal production systems and their impact on the transmission of M. bovis. This paper highlights factors critical to the success of a national eradication programme, including a clear identification of the goals, of the policies that guide actions, and of the sequences of actions that are required within the programme to accomplish these goals. Experience has illustrated the adverse effects of compromise on outcome when the application of fundamental principles of disease control such as sound animal management, removal of known sources of infection, early diagnosis, quarantine, movement control and environmental hygiene are less than enthusiastically promoted and applied. The reality is that where these principles are applied in a sustained manner, the outcome is more likely to be successful. Therein lies the challenge for the risk manager.     

Occurrence of methicillin-resistant Staphylococcus aureus strains from cattle and chicken, and analyses of their mecA, mecR1 and mecI genes

From 2001 to 2005, various specimens from cattle, pigs, and chickens were collected and examined for the presence of methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA). The isolates from 19 specimens were tested for the presence of the mecA gene. Methicillin resistance was confirmed by determining the MICs for these isolates. Among these 19 mecA-positive isolates, 16 were consistently found to be resistant to methicillin. The mecR1 gene was found in all 19 mecA-positive S. aureus, and mecI was also detected in 15 of the mecA-positive S. aureus. The mecI gene had an identical sequence to the reference sequence in 9 of the 15 mecI-positive isolates. Three of the other six isolates had a C to T substitution at nucleotide 202, and one had a G to T substitution at nucleotide 43. These have been previously identified in MRSA from humans. Two isolates from chickens contained an addition of C at position 23. This mutation of MRSA has not been reported elsewhere. In all 15 mecI-positive MRSA, the sequence of the mec promoter/operator region was identical to the reference sequence. This suggests other mechanisms for overcoming the repression of resistance caused by mecI, beyond the simple product interaction between the mecA, mecRI, and mecI genes.     

Pregnancy-associated congestive heart failure in a cat

A 4-year-old, late-term pregnant Himalayan queen was diagnosed with biventricular congestive heart failure characterized by pleural effusion and pulmonary edema. A cesarean section was performed, resulting in the birth of four live kittens, with one surviving to discharge. Congestive heart failure resolved rapidly following surgery. The queen remained asymptomatic for 9 years postoperatively. Volume expansion secondary to pregnancy was thought to result in cardiovascular volume overload and subsequent congestive heart failure.