News

Kidney disease is a leading cause of illness and death in dogs and cats. Treatment of acute and chronic kidney disease is most effective when the disease is recognized early in its course and when treatment is instituted with knowledge of the underlying disease process. To aid in the diagnosis and treatment of kidney disease, the Athens Veterinary Diagnostic Laboratory is now offering renal diagnostic and treatment expertise through its newly established Renal Pathology Consultation Service.

The importance of the veterinarian’s role in animal cruelty cases has recently been highlighted in the news media and numerous journals. In December, the AVMA endorsed a document called “Practical Guidance for the Effective Response by Veterinarians to Suspected Animal Cruelty, Abuse and Neglect” which is intended to aid veterinarians in establishing individual, practice-specific policies and procedures that best serve the needs of the animal, the client, the veterinarian and the community.

Enterotoxemia, also known as overeating or pulpy kidney disease, is a condition caused by Clostridium perfringens type D. These bacteria are normally found in the soil and as part of the normal microflora in the gastrointestinal tract of healthy sheep and goats. Under specific conditions, these bacteria can rapidly reproduce in the animal’s intestine, producing large quantities of toxins. The epsilon toxin produced by C. perfringens Type D is the most significant toxin in producing the disease. Young animals are most susceptible. Sudden and high mortality rates may occasionally occur in lambs and kids. Although adult animals are also susceptible to enterotoxemia, they develop immunity due to frequent exposure to low doses of these toxins.

Two cases of mushroom toxicosis recently have been diagnosed at the TVDIL. The first case involved a 2 year-old mixed breed dog that died following a brief course of vomiting and bloody diarrhea. The second case involved a 12 week-old Labrador Retriever puppy with a history of vomiting with death occurring within 24 hours of the onset of clinical signs. The submitting veterinarian noted that the owners had seen the puppy eat a mushroom. Both dogs had submassive to massive hepatic necrosis which is very typical for mushroom poisoning.

Sparganosis is an infection of tissues by second stage larvae (spargana or plerocercoid) of pseudophyllidean tapeworms. Sparganosis due to pseudophyllidean cestodes such as Sparganum spp. (e.g. Sparganum proliferum) and Spirometra spp. (e.g. Spirometra mansonoides, Spirometra erinaceieuropaei) can occur in body cavities or in tissues of intermediate and paratenic hosts. Sparganum proliferum is phylogenetically identified as a new species in the order pseudophyllidea. The life cycle and the definitive host of Sparganum proliferum is unknown but believed to be similar to that of Spirometra spp. The definite hosts of Spirometra spp. are carnivores, and the eggs are shed in feces. The eggs embryonate in the environment, hatch in water and release coracidia. Coracidia are ingested by intermediate hosts, copepod crustaceans (Cyclops spp.), and develop into procercoids. Second intermediate hosts including fish, reptiles, and amphibians ingest infected copepods and acquire procercoid larvae. Procercoids develop into plerocercoids in the second intermediate hosts. Predators of the second intermediate hosts are infected by the plerocercoids. Plerocercoidosis/sparganosis develops after ingesting procercoids or plerocercoids with contaminated water or infected intermediate hosts. Humans and other mammals including apes, pigs, dogs, and cats can serve as paratenic or second intermediate hosts and develop sparganosis.

Macrorhabdus ornithogaster is a well-known cause of proventriculitis in birds. Although this organism was originally termed Megabacterium due to its large, rod-like appearance, the organism has since been classified as an anamorphic ascomycetous yeast. Clinical signs may be variable and include sudden death or chronic wasting. Diarrhea or enteritis has also been reported in birds colonized by Macrorhabdus; however, these birds can have concurrent enteric parasites, bacterial infections, or other diseases that could cause diarrhea.

Trichomoniasis is a sexually transmitted disease in cattle that can cause significant economic losses in herds. The disease is caused by a single celled parasite, Tritrichomonas foetus. Though the true prevalence of trichomoniasis in cattle is not known, several states have recently enacted stringent rules to control the importation or transmission of the disease.

One of the most common reasons for bringing pets to a veterinarian is skin disease. In many cases, the diagnosis is obvious and treatment is straightforward and successful. However, diagnostic tests are necessary to determine the cause when lesions are unusual; suggestive of serious diseases that require expensive, dangerous, or long term treatment; or do not respond to treatment as expected. Skin biopsies are frequently the most direct means of making a diagnosis because they are relatively easy to do, rapid, cost-effective, and safe for the patient.

Ranaviruses have been implicated as one of the causes of worldwide amphibian declines. These viruses can be deadly to amphibians and have caused mass mortality events in North America. Clinical signs of ranavirus infection may be vague but include hemorrhaging of the skin, lethargy, and swelling (edema). Multiple internal organs may be affected; however, the kidney and liver often are targeted, resulting in hemorrhage and necrosis. In some species, mortality can occur as early as within a few days of exposure.

Histopathology is a powerful and inexpensive diagnostic method. Submission of the right specimen in the right fixative is crucial for microscopic evaluation of biopsy specimens and organ or tissue samples from necropsies. Properly selected, appropriately collected and preserved specimens are very helpful in establishing an accurate diagnosis.

Earlier this year, an outbreak of salmonellosis was associated with tainted peanut butter products from the Peanut Corporation of America, and products are still being recalled as this article is being written. Although most of the products involved were for human consumption, some dog biscuits, rawhides, and other pet treats were among the recalled items. In addition, many pet owners admitted to having fed peanut butter crackers and other recalled human foods to their pets. Given recent deaths in animals due to melamine/cyanuric acid and aflatoxin contaminated dog and cat foods, it is understandable that owners are concerned about food recalls. However, Salmonella-contaminated pet treats and foods actually pose a risk to owners as well as to their pets.

General Guidelines and Principles

• Label slides, tubes, and slide holders: Use patient name and site. Labeling is necessary to prevent and correct sample errors, and to preserve chain of custody. A key, explained in the submission form, can be used for multiple masses/specimens.

Leptospirosis is a potentially fatal and zoonotic bacterial disease caused by pathogenic bacterium Leptospira. There are over 200 serovars maintained in renal tubules of many domestic and wild animal species.

The Georgia Veterinary Diagnostic Laboratories are two of only 41 accredited veterinary laboratories in North America. We are accredited by the American Association of Veterinary Laboratory Diagnosticians (AAVLD). The goal of the AAVLD is to assist Labs meet or exceed the World Organization for Animal Health Quality Standards and Guidelines for Veterinary Laboratories. Meeting these quality standards requires the effort of every staff member, from the directors and pathologists to the technicians and administrative personnel.

Bovine enterovirus (BEV) belongs to the family Picornaviridae (picornaviruses), which consists of small (18–30 nm), nonenveloped viruses with an icosahedral capsid that encloses a single copy of positive-sense RNA genome. Bovine enterovirus is in the genus Enterovirus, along with poliovirus, human enterovirus, coxsackieviruses, swine vesicular disease virus, echovirus 11, and others. Originally classified into several serotypes, only two serotypes, BEV-1 and BEV-2 are now recognized.Because of the unavailability of type specific antisera or a commercially available diagnostic test, a genotypic classification, which supports previous recognized serological distinctions has been proposed.

Veterinary pathologists are challenged daily with making a diagnosis on a variety of surgical biopsies. Many times clinicians will opt for surgical biopsy hoping for a definitive diagnosis that will give relevant information for therapy and prognosis. The pathologist becomes that one person from whom clinicians and owners wait for an answer. At times, however, the histological findings are inconclusive. Some examples of challenging diagnoses are discussed below.

Many cedar waxwings were found dead in a yard in Thomas County, Georgia, in April, 2009. Five of these submitted to the Tifton Veterinary Diagnostic and Investigational Laboratory, where they were examined grossly and microscopically.

Canine distemper virus (CDV) infects and causes disease in domestic dogs and many wild carnivores, including coyotes, ferrets, foxes, lions, mink, raccoons, and skunks. Although sustained vaccination of domestic dog populations has greatly reduced the incidence of canine distemper, the disease is still prevalent worldwide and now occurs in sporadic outbreaks. Young puppies between 3 and 6 months of age are more susceptible to infection and undergo more severe disease than adult dogs. However, non-vaccinated older dogs are also highly susceptible to infection and disease.

Johne’s disease (JD), caused by Mycobacterium avium subspecies paratuberculosis (MAP), is an economically important disease of ruminants. The disease is characterized by chronic, progressive granulomatous enteritis and affects a wide variety of hosts including cattle, sheep, goats, llamas, alpacas, bison and deer. The U.S. dairy cattle industry estimates an annual economic loss of $220 million due to JD. The presence of MAP in milk, its resistance to pasteurization temperatures, and its possible association with Crohn’s disease in humans suggest a significant public health risk.

Staphylococci are Gram-positive, facultative anaerobic cocci. The genus is subdivided into many different species and most of them are host adapted. For the most part, staphylococci are skin commensals of healthy individuals where they can be carried transiently or permanently and only cause disease when there is a breech of epithelial integrity. The most common clinical presentations are skin abscesses. The species of staphylococci most frequently isolated from both healthy and sick dogs and cats is Staphylococcus intermedius (SI). Staphylococcus aureus (SA), although isolated from animal infections, is not as common as SI. The susceptibility profiles of both staphylococci species is changing, with clear increases in the number of isolates that are multidrug resistant (MDR).

Immunohistochemistry has been available for many years, but is becoming much more widely used with advances in automated staining processes, available antibodies, and knowledge. The principle behind the technique is relatively simple: all cells have antigens, and the distribution of antigens is tissue-dependent.