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.     

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.     

Parasites of Dogs from Indian Settlements in Northwestern Canada: A Survey with Public Health Implications

A total of 959 faecal samples were obtained from dogs in 12 native communities in Northern Saskatchewan, Central and Northern Alberta and the Northwest Territories. All samples were examined using a flotation technique. Samples from an area of endemic human amoebic infections were also examined by a formol-ether sedimentation method. Eighteen necropsies were performed.

Entamoeba histolytica cysts were recovered from dog faeces at Loon Lake, Saskatchewan.

Toxocara canis had low incidence in Saskatchewan and Central Alberta, and appeared to be almost non-existent further North. Toxascaris leonina was found in all areas surveyed. Canine hookworm infections were plentiful in all areas, the highest incidence being recorded from Northern Alberta and Northwest Territories. Many Taenia (or Echinococcus) infections were found consistently in all areas. Only one infection with Dipylidium caninum was discovered.

Metorchis conjunctus infections were found to be common in the Saskatchewan reserves. Infections with Diphyllobothrium sp. were found in all communities with access to good fishing. One specimen of Dioctophyma renale was recovered at necropsy.

Infections with parasites of no known zoonotic importance such as Trichuris, Alaria and Isospora species were also recorded.

     

Use of intra-articular administration of ethyl alcohol for arthrodesis of the tarsometatarsal joint in healthy horses

OBJECTIVE: To evaluate the efficacy and safety of intra-articular administration of ethyl alcohol for arthrodesis of tarsometatarsal joints in horses. ANIMALS: 8 healthy female horses without lameness or radiographic evidence of tarsal joint osteoarthritis. PROCEDURE: In each horse, 1 tarsometatarsal joint was treated with 4 mL of 70% ethyl alcohol and the opposite joint was treated with 4 mL of 95% ethyl alcohol. Lameness examinations were performed daily for 2 weeks, followed by monthly evaluations for the duration of the 12-month study. Radiographic evaluations of both tarsi were performed 1 month after injection and every 3 months thereafter. Gross and histologic examinations of the tarsi were undertaken at completion of the study. RESULTS: Horses had minimal to no lameness associated with the treatments. Radiography revealed that 8 of 16 joints were fused by 4 months after treatment, with significantly more joints fused in the 70% ethyl alcohol group. Fifteen of 16 joints were considered fused at postmortem examination at 12 months. Gross and histologic examinations revealed foci of dense mature osteonal bone spanning the joint spaces. Bony fusion appeared to be concentrated on the dorsolateral, centrolateral, and plantarolateral aspects of the joints. Significant differences were not detected between treatment groups for lameness or pathologic findings. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of ethyl alcohol into the tarsometatarsal joint of healthy horses appeared to facilitate arthrodesis of the joint in a pain-free manner. Results warrant further investigation into the potential use of ethyl alcohol in horses clinically affected with osteoarthritis of the tarsometatarsal and distal intertarsal joints.