The medical, veterinary and economic importance of blackflies in South Africa, and the historical development of blackfly control programmes in various South African rivers, are reviewed in this paper. In 1996 it was estimated that blackflies can cause more than R 88 million damages per annum along the middle and lower Orange River where Simulium chutteri is considered the main pest species. A clear link between the construction of dams and the spread of the blackfly problem was shown. Four phases characterize the development of blackfly control in South Africa: (1) during the 1960s blackflies in the Vaal River were controlled with DDT; (2), during the 1970s and into the 1980s blackflies were controlled using water-flow manipulation; (3) when used at strategic times, water-flow manipulation could be used to enhance the effect of natural predator populations; and (4) during the 1990s the organophosphate temephos and toxins produced by the bacterium Bacillus thuringiensis var. israelensis were tested for their efficacy against blackflies. The larvicides temephos and B. thuringiensis proved to be effective and are still used in several control programmes. The latest research focuses on the factors that influence adult blackfly survival and annoyance, as well as the development of methods that can be used to protect sheep from blackfly attacks.

During winter populations of Argas arboreus from heronries of the cattle egret, Bubulcus ibis, in South Africa are composed of adults, with some predominance of males, and II-IV instar nymphs, in a state of diapause. The period of tick activity, including reproduction and development of eggs, larvae and N1 nymphs, is synchronized with the nesting and breeding season of their avian hosts. It begins during spring with the return of birds to the heronry, and ceases in autumn through induction of reproductive diapause in engorged females, and behavioural diapause in unfed nymphs and adult ticks. Many ticks showed morphological anomalies and malformations, the study of which could possibly be used for monitoring of environmental pollution.

Objective-To explore whether early analysis of spatial data may result in identification of variables associated with epidemic spread of foot and mouth disease. Sample Population-37 farms with infected cattle (ie, case farms) reported within the first 6 days of the 2001 Uruguayan foot-and-mouth disease epidemic. Procedure-A georeferenced database was created and retrospective analysis was performed on case farm location in relation to farm density, cattle density, farm type (ie, beef vs dairy cattle production), road density, case farm distance to the nearest road, farm size, farm ownership, and day of infection. Mean or median results of 1 to 3 day versus 4 to 6 day spatial data were compared. Spatial-temporal associations were investigated by correlation analysis. Results-Comparison of mean or median values between the first 3 days and days 4 to 6 of the epidemic and results of correlation analysis indicated a significant increase in road density, cattle density, and dairy cattle production and a significant decrease in farm size and case farm distance to the nearest road that developed over time. A route that linked most case farms by the shortest possible distance and also considered significantly associated variables was created. It included 86.1% of all case farms reported by 60 days into the epidemic. Conclusions and Clinical Relevance-Epidemic direction can be assessed on the basis of road density and other spatial variables as early as 6 days into an epidemic. Epidemic control areas may be more effectively identified if local and regional georeferenced data are considered.

The objective of this prospective clinical study was to evaluate the accuracy of pulse oximetry and capnography in healthy and compromised horses during general anesthesia with spontaneous and controlled ventilation. Horses anesthetized in a dorsal recumbency position for arthroscopy (n = 20) or colic surgery (n = 16) were instrumented with an earlobe probe from the pulse oximeter positioned on the tip of the tongue and a sample line inserted at the Y-piece for capnography. The horses were allowed to breathe spontaneously (SV) for the first 20 min after induction, and thereafter ventilation was controlled (IPPV). Arterial blood, for blood gas analysis, was drawn 20 min after induction and 20 min after IPPV was started. Relationships between oxygen saturation as determined by pulse oximetry (SpO2), arterial oxygen saturation (SaO2), arterial carbon dioxide partial pressure (PaCO2), and end tidal carbon dioxide (P(et)CO2), several physiological variables, and the accuracy of pulse oximetry and capnography, were evaluated by Bland–Altman or regression analysis. In the present study, both SpO2 and P(et)CO2 provided a relatively poor indication of SaO2 and PaCO2, respectively, in both healthy and compromised horses, especially during SV. A difference in heart rate obtained by pulse oximetry, ECG, or palpation is significantly correlated with any pulse oximeter inaccuracy. If blood gas analysis is not available, ventilation to P(et)CO2 of 35 to 45 mmHg should maintain the PaCO2 within a normal range. However, especially in compromised horses, it should never substitute blood gas analysis.

Objective-To determine pharmacokinetics and tissue concentrations of azithromycin in ball pythons ( Python regius ) after IV or oral administration of a single dose. Animals-2 male and 5 female ball pythons. Procedures-Using a crossover design, each snake was given a single dose of azithromycin (10 mg/kg) IV. After a 4-week washout period, each snake was given a single dose of azithromycin (10 mg/kg) orally. Blood samples were collected prior to dose administration and 1, 3, 6, 12, 24, 48, 72, and 96 hours after azithromycin administration. Azithromycin was quantitated by use of liquid chromatography-mass spectrometry. Results-After IV administration, azithromycin had an apparent volume of distribution of 5.69 L/kg and a plasma clearance of 0.19 L/h/kg. Harmonic means for the terminal half-life were 17 hours following IV administration and 51 hours following oral administration. Mean residence times were 37 and 94 hours following IV and oral administration, respectively. Following oral administration, azithromycin had a peak plasma concentration (Cmax) of 1.04 micrograms/mL, a time to Cmax of 8.4 hours, and a prolonged mean absorption time of 57 hours. Mean oral bioavailability was 77%. Tissue concentrations ranged from 4 to 140 times the corresponding plasma concentration at 24 and 72 hours after azithromycin administration. Conclusions and Clinical Relevance-Azithromycin is well absorbed and tolerated by ball pythons. On the basis of plasma pharmacokinetics and tissue concentration data, we suggest an azithromycin dosage in ball pythons of 10 mg/kg, orally, every 2 to 7 days, depending upon the site of infection and susceptibil ity of the infective organism.

Objective-To determine the effects of endotoxin administration on thyroid function test results and serum tumor necrosis factor-alpha (TNF-alpha) activity in healthy dogs. Animals-6 healthy adult male dogs. Procedures-Serum concentrations of thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3'5'-triiodothyronine (rT3), free T4 (fT4), and endogenous canine thyroid stimulating hormone (TSH), and TNF-alpha activity were measured before (day-1; baseline), during (days 0 to 3), and after (days 4 to 24) IV administration of endotoxin every 12 hours for 84 hours. Results-Compared with baseline values, serum T3 concentration decreased significantly, whereas rT3 concentration increased significantly 8 hours after initial endotoxin administration. Serum T4 concentration decreased significantly at 8 and 12 hours after initiating endotoxin administration. Serum T4 concentration returned to reference range limits, then decreased significantly on days 6 to 12 and 16 to 20. Serum fT4 concentration increased significantly at 12, 24, and 48 hours after cessation of endotoxin treatment, compared with baseline values. Serum rT3 concentration returned to reference range, then decreased significantly days 5 and 7 after stopping endotoxin treatment. Serum TNF-alpha activity was significantly increased only 4 hours after initial endotoxin treatment, compared with baseline activity. Conclusions and Clinical Relevance-Endotoxin administration modeled alterations in thyroid function test results found in dogs with spontaneous nonthyroidal illness syndrome. A decrease in serum T4 and T3 concentrations and increase in serum rT3 concentration indicate impaired secretion and metabolism of thyroid hormones. The persistent decrease in serum T4 concentration indicates that caution should be used in interpreting serum T4 concentrations after resolution of an illness in dogs.

Recently, a radioimmunoassay (RIA) for measurement of canine pancreatic lipase immunoreactivity (cPLI) in serum was developed and validated. However, RIAs require frequent use of radioactive materials. Therefore, the goal of this project was to develop and validate an enzyme-linked immunosorbent assay (ELISA) for cPLI. After purifying cPL, we developed and purified antiserum against cPL in rabbits. The purified antibody was bound to microtitre plates and used to capture antigen. A portion of the purified antibody was biotinylated and used to identify the captured antigen. Streptavidin labelled with horseradish peroxidase and a horseradish peroxidase substrate were used for detection. The assay was validated by determination of sensitivity, working range, linearity, accuracy, precision, and reproducibility. The reference interval for serum cPLI was determined by the central 95th percentile in 74 clinically healthy dogs: 2.2 to 102.1 μg/L. The sensitivity and the upper limit of the working range were 0.1 and 999.2 μg/L, respectively. The ratios of observed to expected values for dilutional parallelism for 6 serum samples ranged from 0.0 to 148.8%; the ratios for spiking recovery for 4 serum samples ranged from 90.4 to 112.6%, assuming 55% recovery of the cPL. Coefficients of variation for intra- and interassay variability for 6 different serum samples were 2.4, 3.4, 4.1, 5.8, 7.4, and 10.0% and 5.9, 7.7, 11.6, 13.9, 23.5, and 46.2%, respectively. We conclude that the ELISA described here is sufficiently sensitive, linear, accurate, precise, and reproducible for clinical application. Evaluation of its clinical usefulness for the diagnosis of exocrine pancreatic disorders in dogs is under way.

Although the developmental potential of oocytes is related to oocyte quality, whether the expression of specific genes is altered in oocytes of different quality and in resulting embryos is not known. Semi-quantitative reverse transcription-polymerase chain reaction was used to compare the relative abundance of 2 transcripts for housekeeping proteins (β-actin and ribosomal protein L30) and 3 transcripts for growth factor ligand or receptors (platelet derived growth factor receptor α (PDGFRα), basic fibroblast growth factor (bFGF)), in mature bovine oocytes of high versus low developmental potential. The transcripts for L30, PDGFRα, and bFGF in 16-cell embryos originating from these oocytes were also examined. No significant effect of oocyte quality was detected for any of the transcripts examined from oocytes or 16-cell embryos. In conclusion, a lower developmental potential of oocytes with advanced signs of atresia, was not associated with a lower level of abundance of the transcripts examined.