Canine parentage testing based on microsatellite polymorphisms.

To establish an accurate method for parentage testing in dogs, microsatellite DNA repeat length polymorphisms were examined. We selected twenty microsatellite markers reported previously and examined their application for parentage testing in Beagles and Labrador Retrievers. Heterozygosity (He), Polymorphism Information Content (PIC), the probabilities of Paternity Exclusion (PE) and the combined PE were calculated from allelic frequencies of the markers. All markers amplified by polymerase chain reactions were polymorphic and many markers showed high He and PIC in the both breeds. The final combined PEs in Beagles and Labrador Retrievers were 0.999994 and 0.999920, respectively. The results suggest that the twenty markers can be applied for routine parentage testing in dogs.     

Canine inherited retinal degenerations: update on molecular genetic research and its clinical application

Inherited retinal degenerations in the dog include generalised progressive retinal atrophy, retinal pigment epithelial dystrophy, congenital stationary night blindness and day blindness (hemeralopia). The clinical phenotype and pathology of these diseases closely resemble some types of human inherited retinal degeneration, in particular retinitis pigmentosa, one of the most common inherited causes of blindness in man. Molecular genetic investigations aim to identify the genetic mutations underlying the canine inherited retinal degenerations. Two major research strategies, candidate gene analysis and linkage analysis, have been used. To date, candidate gene analysis has definitively identified the genetic mutations underlying nine inherited retinal degenerations, each in a different breed of dog, and linkage studies have identified genetic markers for a further retinal degeneration which is found in at least six different breeds. This review outlines the research strategy behind candidate gene and linkage studies and summarises recent results in the search for genetic causes of canine inherited retinal degenerations. The aim is to increase awareness of this rapidly changing field and to show how the research can be used to develop genetic tests for these diseases and thereby reduce the incidence of inherited eye disease in dogs.     

Canine protothecosis.

Canine protothecosis remains a difficult condition to manage. The paucity of clinical cases hinders the development of successful treatment strategies. The clinical signs associated with the disease are nonspecific, and the course is so insidious that, by the time a definitive diagnosis is reached, the organism has often disseminated throughout the body. At this point, the condition is beyond treatment, and death occurs owing to failure of any number of organ systems, including the gastrointestinal, cardiovascular, renal, and central nervous systems. It is of some encouragement that the few patients that have undergone aggressive early treatment have survived longer than patients presenting late in the disease course. Nevertheless, the outlook for any dog with protothecosis is grave, and it remains to be determined whether early diagnosis can truly provide a better long-term prognosis. By including protothecosis as a consideration for dogs initially brought in with a history of chronic diarrhea or acute blindness and with a subsequent finding of exudative retinal separation, early diagnosis is possible. This recognition potentially affords the opportunity for an immune status work-up and intervention with increasingly better treatment options.     

Canine borreliosis.

A guild of organisms carried by the same vector (Ixodes ticks) in Lyme-endemic areas may be confounding the understanding of Lyme disease in dogs. A new diagnostic method, the C6 peptide test for Lyme, and serology and PCR testing for Ehrlichia, Babesia, and Bartonella species will help to sort out seroprevalence and symptomatology caused by exposure to these agents or by coinfections. In addition, Rickettsia, Leptospira, Mycoplasma species, and more could be involved in dogs diagnosed with a "doxycycline-responsive" disease. The author does not recommend treating asymptomatic Borrelia carrier dogs, but does recommend screening them for proteinuria and for exposure to other agents. A positive Lyme titer is a marker of exposure to Ixodes ticks and the agents they carry. The risk/benefit of vaccination will be understood better as the symptomatology and immunopathogenesis of Lyme disease are defined. Meanwhile, tick control is highly recommended for all dogs in Lyme-endemic areas.     

Canine influenza.

In 2004, the isolation of an influenza virus from racing greyhounds changed the point of reference for discussions about influenza virus in dogs. A virus isolated from greyhounds did not have its origin in a previously described human influenza virus but came from a virus with an equine history. More significantly, evidence emerged to indicate that the virus was capable of transmission from dog to dog. This virus is now referred to as canine influenza virus (CIV) and is the focus of this review. Because the history of CIV is relatively short, the impact of this virus on canine health is yet to be determined.     

Canine vaccination.

New technologies for vaccine development and infectious disease diagnosis are likely to be introduced in the near future. With this new technology comes the opportunity to vaccinate companion animals against even more infectious agents than is currently practiced in the United States. As we look forward, it becomes particularly important to review current vaccination standards applied to dogs with respect to current knowledge of duration of immunity, awareness of incidence, and likelihood of injurious or even fatal adverse events associated with vaccination, and individual risk factors that dictate which vaccines are most appropriate at which stage of life.     

Canine babesiosis.

Canine babesiosis is a tickborne, protozoal, hemoparasitic disease that can cause varying degrees of hemolytic anemia, splenomegaly, thrombocytopenia, and fever. Babesia organisms frequently are classified as large or small. Large Babesia infections are attributed to one of three subspecies of Babesia canis. All small Babesia infections previously were attributed to B gibsoni, but molecular analysis and DNA sequencing have revealed that there are at least three small piroplasms infecting dogs. Correctly identifying the infectious agent is important for treatment planning and prognosis.     

Canine cryptorchidism.

Canine cryptorchidism is a congenital defect that results from sex-limited autosomal recessive gene(s). Incidence is higher in some breeds, especially in smaller and inbred ones. Parents of affected puppies are carriers. Unilateral cryptorchid dogs can be fertile, and affected individuals and their siblings should be eliminated from a breeding program to decrease incidence of the defect. Androgen and gonadotropin treatments have been tried with little or no success. Bilateral orchidectomy is the treatment of choice because of the common sequelae of testicular neoplasia and torsion.     

Canine gastritis.

Gastritis--inflammation of the stomach--is a frequently cited differential yet rarely characterized diagnosis in cases of canine anorexia and vomiting. Although the list of rule-outs for acute or chronic gastritis is extensive, a review of the veterinary literature reveals fewer than 15 articles that have focused on clinical cases of canine gastritis over the last 25 years. The dog frequently appears in the human literature as an experimentally manipulated model for the study of endoscopic techniques or the effect of medications on gastric mucosa. In the veterinary patient, cases of acute gastritis are rarely pursued with the complete diagnostic armamentarium, and cases of chronic gastritis are rarely found to occur as an entity isolated from the rest of the gastrointestinal tract. This article focuses on those findings most clinically relevant to cases of canine gastritis in veterinary medicine.     

Canine polypoid cystitis.

The clinical, laboratory, and radiographic characteristics of polypoid cystitis in 2 dogs were similar to those commonly associated with neoplasms of the urinary bladder. Gross appearance of the polyps did not permit differentiation between inflammation and neoplasia; microscopic examination of excised tissue was required to establish a definitive diagnosis. Following surgical extirpation of the polyps, remission of clinical signs was induced by prolonged antibacterial therapy.     

Canine eosinophilic bronchopneumopathy.

Eosinophilic bronchopneumopathy (EBP) is a disease characterized by eosinophilic infiltration of the lung and bronchial mucosa, as demonstrated by examination of bronchoalveolar lavage fluid cytologic preparations or histologic examination of the bronchial mucosa. Although the precise cause of EBP is unknown, a hypersensitivity to aeroallergens is suspected. The diagnosis relies on typical history and clinical signs, demonstration of bronchopulmonary eosinophilia by cytology or histopathologic examination, and exclusion of known causes of lower airway eosinophilia. Most dogs display an excellent response to oral corticosteroid therapy; however, side effects of this treatment can be limiting. New therapeutic approaches are being studied, including the use of aerosol therapy, cyclosporine, or drugs interfering with T helper 2 immune response.     

Canine viral infections.

The ophthalmic effects of viral infection are varied. With the added possibility for pathologic effects of attenuated vaccine viruses, the diagnosis of viral diseases can be a challenge. In many cases, ocular manifestations can provide added support to a presumptive diagnosis of viral disease, thereby underscoring the benefit of thorough ophthalmic examination of any animal with nonspecific signs of illness.