Factors contributing to the public health and economic importance of waterborne zoonotic parasites

This is the first of a series of review articles in a Special Issue publication on waterborne zoonotic parasites. A brief historical overview of the occurrence and importance of waterborne parasites, dating from early civilization is presented. The article considers the diversity of parasites including protozoa, nematodes, cestodes and trematodes and the related zoonotic organism microsporidia. Many of the life cycle stages and their characteristics, which make parasites environmentally resistant and suitable for waterborne transmission are discussed. Surfaces of transmission stages consist of multiple layers of proteins, lipids, chitin or other substances capable of withstanding a variety of physical and chemical treatments. Delivery of waterborne parasites is facilitated by various mass distribution systems to consumers, and by transport and intermediate hosts such as fish and filter-feeding invertebrates which are consumed by humans. The article discusses the trends in global warming and climate change and potential for concurrent rise in waterborne disease outbreaks due to parasites. Impacts of technological modernization and globalization on the transmission of zoonotic waterborne zoonotic parasites are considered, including the effects of large-scale agricultural practices, rapid transportation of goods, and widespread movement of individuals and animals. Finally, transmission features and parasite attributes which contribute to concerns about accidental or orchestrated waterborne disease outbreaks are discussed.     

Temporal trends in reproductive performance in Irish dairy herds and associated risk factors

: Irish dairy herd fertility has been declining since the 1980s. The extent, nature and causes of this decline in fertility and the current status of Irish dairy herd fertility were described. An increase in calving interval of approximately one day per year has been recorded. The principal components of this trend have been an increased incidence of postpartum endocrinopathies, reduced expression of oestrus and a fall in conception rate. Both submission rate and calving-to-service interval have increased slightly over time. Significant risk factors associated with these trends have been strain substitution within the Holstein-Friesian breed and single trait selection for milk production. Critically, these changes have been reflected in loss of body condition. Contributory factors included increased herd size and possibly increased use of DIYAI. The most recent Irish study showed that 48% of cows conceived to first service and 14% of cows were not pregnant at the end of the industry-average 15-week spring breeding season. However, the top quartile of herds achieved a first-service conception rate of 59%, illustrating the wide variation between herds. These phenotypic trends were attributed to both genetic and environmental factors and their interactions. Recent Irish dairy herd fertility performance falls short of the targets set for seasonal compact calving.     

Influence of antiarrhythmia therapy on survival times of 19 clinically healthy Doberman pinschers with dilated cardiomyopathy that experienced syncope, ventricular tachycardia, and sudden death (1985-1998)

Overtly healthy Doberman pinschers, having moderate to severe myocardial failure secondary to dilated cardiomyopathy, which experienced ventricular tachycardia, syncope or collapse, and sudden death were studied to determine the effect of antiarrhythmic medication on their clinical outcome. Antiarrhythmia drug therapy may have retarded sudden death in 13 treated dogs compared to the six dogs not administered antiarrhythmia drugs.     

Clinical effects of short-term oral budesonide on the hypothalamic-pituitary-adrenal axis in dogs with inflammatory bowel disease

Six dogs were entered into a 30-day, prospective, nonrandomized, uncontrolled clinical trial evaluating the effects of an oral preparation of budesonide on the hypothalamic-pituitary-adrenal (HPA) axis during therapeutic management of active inflammatory bowel disease. Oral budesonide, at a dose of 3 mg/m(2), was administered once daily. Upon entry and completion of the trial, serum basal cortisol, adrenocorticotropic (ACTH)-stimulated cortisol, endogenous ACTH concentration, serum alkaline phosphatase (SAP) activity, and urine specific gravity were evaluated, as well as owner assessment of glucocorticoid-associated side effects. Significant suppression of the HPA axis occurred. No significant differences in SAP activity, urine specific gravity, or owner-subjective assessments were detected.     

Diet modulates proteinuria in heterozygous female dogs with X-linked hereditary nephropathy

Young adult heterozygous (carrier) female dogs with X-linked hereditary nephropathy (XLHN) have glomerular proteinuria but are otherwise healthy. Because data regarding dietary influences on the magnitude of proteinuria in dogs with spontaneous glomerular disease are not available, 12 such dogs were studied in a double crossover experiment intended to determine effects of altering dietary protein intake for up to 6 weeks. Dogs were blocked by urine protein : creatinine ratio (UPC) and randomly assigned to receive 2 diets: high protein (34.6% dry matter [DM], HP) or low protein (14.1% DM, LP) fed in HP-LP-HP or LP-HP-LP sequence. Food intake was measured daily, body weight (BW) was measured twice weekly, and UPC, plasma creatinine, blood urea nitrogen, phosphorus, albumin, and protein concentrations were measured at 2-week intervals. Nutrient digestibility was measured during the third treatment period. Diet had a significant effect (P < .0001) on all measured variables except plasma phosphorus (P > .5), but unintended differences in digestibility of protein and energy (P < or = .01) prevented assignment of the diet effect exclusively to protein. Proteinuria was greater (UPC 4.7 +/- 2.2 versus 1.8 +/- 1.1, P < .0001) when the HP diet was fed, but the LP diet did not maintain starting BW or plasma albumin concentration within the normal reference range. Diet greatly affects the magnitude of proteinuria in XLHN carrier females. Dietary protein restriction can reduce proteinuria in dogs with glomerular disease, but BW and blood protein concentrations may not be maintained if the restriction is too severe.     

Evaluation of microbial culture of pooled fecal samples for detection of Mycobacterium avium subsp paratuberculosis in large dairy herds

OBJECTIVE: To evaluate sensitivity of microbial culture of pooled fecal samples for detection of Mycobacterium avium subsp paratuberculosis (MAP) in large dairy herds and assess the use of the method for estimation of MAP prevalence. ANIMALS: 1,740 lactating cows from 29 dairy herds in California. PROCEDURE: Serum from each cow was tested by use of a commercial ELISA kit. Individual fecal samples were cultured and used to create pooled fecal samples (10 randomly selected fecal samples/pool; 6 pooled samples/herd). Sensitivity of MAP detection was compared between Herrold's egg yolk (HEY) agar and a new liquid culture method. Bayesian methods were used to estimate true prevalence of MAP-infected cows and herd sensitivity. RESULTS: Estimated sensitivity for pooled fecal samples among all herds was 0.69 (25 culture-positive pools/36 pools that were MAP positive). Sensitivity increased as the number of culture-positive samples in a pool increased. The HEY agar method detected more infected cows than the liquid culture method but had lower sensitivity for pooled fecal samples. Prevalence of MAP-infected cows was estimated to be 4% (95% probability interval, 2% to 6%) on the basis of culture of pooled fecal samples. Herd-level sensitivity estimate ranged from 90% to 100% and was dependent on prevalence in the population and the sensitivity for culture of pooled fecal samples. CONCLUSIONS AND CLINICAL RELEVANCE: Use of pooled fecal samples from 10 cows was a cost-effective tool for herd screening and may provide a good estimate of the percentage of MAP-infected cows in dairy herds with a low prevalence of MAP.     

Investigation of the composition, turnover, and thermal properties of ruptured cranial cruciate ligaments of dogs

OBJECTIVE: To assess different components of the extracellular matrix with regard to their thermal properties, composition, and turnover in ruptured cranial cruciate ligaments (CCLs) of dogs, compared with components of intact CCLs from a breed predisposed to CCL failure. SAMPLE POPULATION: Ruptured CCLs obtained from 8 dogs of breeds predisposed to ruptured CCLs and intact CCLs from 12 cadaveric Labrador Retrievers. PROCEDURE: Ruptured and intact CCLs were analyzed for water content; collagen content and collagen cross-links were evaluated via hydroxyproline and amino-acid analyses, respectively. Glycosaminoglycan (GAG) content was analyzed via dimethylmethylene blue and uronic acid assays. Matrix metalloproteinases (MMPs)-2 and -9 and the tissue inhibitors of metalloproteinases (TIMPs)-1 and -2 were detected via gelatin SDS-PAGE zymography and reverse gelatin zymography. Thermal analysis of ligaments was performed by use of differential scanning calorimetry. RESULTS: Ruptured CCLs had significantly higher lamounts of immature cross-links, total and sulfated GAGs, and water content, compared with that of the intact ligaments. Compared with intact CCLs, concentration of pro-MMP-2 was significantly higher in ruptured CCLs; the maximum temperature of collagen denaturation was significantly lower in the ruptured CCLs. CONCLUSIONS AND CLINICAL RELEVANCE: The extracellular matrix of ruptured CCLs had an increased matrix turnover indicated by increased collagen and GAG synthesis, compared with that of intact CCLs. Although the extracellular matrix changes may have occurred before ligament rupture, it is possible that these observed changes may be part of a reparative process after rupture.     

Efficacy of ceftiofur hydrochloride sterile suspension administered parenterally for the treatment of acute postpartum metritis in dairy cows

OBJECTIVE: To evaluate the efficacy of ceftiofur hydrochloride sterile suspension administered parenterally for treatment of acute postpartum metritis (APM) in dairy cows. DESIGN: Multilocation, randomized block, field trial. ANIMALS: 406 cows in the first 14 days postpartum. PROCEDURE: Cows with rectal temperatures > or = 39.5 degrees C (103.1 degrees F) without clinical signs of respiratory or gastrointestinal tract disease and with a fetid vaginal discharge were allocated randomly in blocks of 3 to 3 treatment groups: sterile saline (0.9% NaCl) solution administered at a dosage of 2 mL/45.4 kg (2 mL/100 lb), SC or IM, once daily for 5 days (control); or ceftiofur hydrochloride administered at a dosage of 1.1 or 2.2 mg of ceftiofur equivalents (CE)/kg (0.5 or 1 mg/lb, respectively), SC or IM, once daily for 5 days. Cows were evaluated on days 6, 10, and 14, and clinical cure or failure to cure was determined. Clinical cure was defined as no additional antimicrobial treatment administered, rectal temperature < 39.5 degrees C, and absence of a fetid vaginal discharge. RESULTS: On day 14, clinical cure rates were 77%, 65%, and 62% for the 2.2 mg of CE/kg, 1.1 mg of CE/kg, and control groups, respectively. No significant differences were detected in clinical cure rates between control and treatment groups on day 10 or 6. CONCLUSIONS AND CLINICAL RELEVANCE: Ceftiofur hydrochloride administered at a dosage of 2.2 mg of CE/kg, SC or IM, once daily for 5 days was efficacious for treatment of APM in dairy cows.