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.     

Canine systemic fungal infections.

The principal route of infection for the disseminated fungal diseases discussed in this article is inhalation. In some cases, direct wound contamination and ingestion may also have an important role in the pathogenesis of the disease, especially in histoplasmosis. Another common theme of these diseases is the response of the immune system. If the inoculum is small and the animal is not immunocompromised, the infection may be limited to the respiratory tract and may resolve with few or no clinical signs. Dogs are usually presented to the veterinarian when the fungus has disseminated throughout the body via the circulatory or lymphatic systems, thus causing clinical signs secondary to specific organ infection. Draining skin tracts and lymphadenopathy occur in several of the diseases. The ocular location that is frequently affected is the choroid, where the organisms cause cell-mediated chorioretinitis. Early detection of these changes is important for saving vision and for diagnosing the systemic nature of the disease. Treatment is often effective, especially early in the disease, although it is expensive and long-term, with many animals needing over a year of treatment. Sometimes the treatment must continue lifelong. Ocular disease may not respond to treatment even when respiratory and other organ system clinical signs are rapidly improving. This isolation of the eye is similar to that of the CNS and requires regular monitoring of ocular disease, especially in the fundus, to ensure that systemic drugs are penetrating into the eye. Once the disease progresses to the anterior segment, the ocular prognosis worsens. Better penetration of the blood-retinal and blood-aqueous barriers may be achieved with fluconazole when compared with the other antifungal drugs. Secondary inflammatory ocular disease must also be monitored and treated appropriately to prevent scarring, which may cause vision loss or glaucoma.     

Canine systemic bacterial infections.

Although systemic bacterial diseases are an uncommon cause of uveitis in dogs, they should be included in the differential diagnoses for uveitis. A work-up for uveitis should include tests for B. canis and B. burgdorferi. If an aqueous centesis is performed, Leptospira titers or PCR can be performed on the aqueous humor and the serum. Better documentation of the role of Leptospira and B. burgdorferi in uveitis in the dog is needed. Any suspected cases should be worked-up thoroughly. If the dog does prove to be positive for the organism, the case should be submitted to a peer-reviewed journal.     

Canine respiratory virus infections

The aetiology and pathogenesis of canine respiratory disease is complex. Current research has implicated a number of viruses in this important disease problem. Distemper virus, two adenoviruses (ICH virus and A26/61 virus), herpesvirus and reovirus have all been isolated from the respiratory tract of dogs and are all capable of causing respiratory lesions in experimental animals. The general features of each of these virus infections are discussed.
Résumé. L'étiologie et la pathogenèse des maladies respiratoires chez le chien est complexe. Une recherche en cours a impliqué un nombre de virus dans cette maladie qui pose un problème important. Le virus de la maladie du jeune âge chez le chien, les adénovirus twp (le virus ICH et le virus A 26/61), le virus de l'herpts et le réovirus ont été tous isolés des voies respiratoires de chiens et sont tous susceptibles de causer des lesions respiratoires chez des animaux expérimentaux. On discute des traits généraux de chacune de ces infections par virus.
Zusammenfassung. Die Ätiologie und Pathogenese von Hunde-Atmungskrankheiten ist komplex. Gegenwärtige Forschung hat eine Reihe von Viren mit diesem wichtigen Krankheitsproblem in Verbindung gebracht. Staupevirus, twp Adenovirus (ICH Virus und A26/61 Virus), Herpesvirus und Reovirus wurden alle vom Luftweg von Hunden isoliert und sind alle fähig Atemläsionen in Versuchstieren zu verursachen. Die allgemeinen Merkmale von diesen Virusinfektionen wurden erörtet.     

Canine and feline primary ocular bacterial infections.

Bacterial infections are frequently associated with diseases of the eyelids, cornea, and conjunctiva. Animals sustaining KCS commonly have bacterial infections of the external eye owing to a lack of antimicrobial properties present in the normal tearfilm. Infection can occur in the nasolacrimal duct or lacrimal sac, which is referred to as dacryocystitis. Severe corneal ulcers are frequently infected with bacteria, especially Pseudomonas sp. Three new topical ophthalmic antibiotics have recently become commercially available: ciprofloxacin, norfloxacin, and ofloxacin.     

Prevalence of selected rickettsial infections in cats in Southern Germany

Prevalence of Anaplasma, Ehrlichia, Neorickettsia, and Wolbachia DNA in blood of 479 cats collected in different veterinary clinics in Southern Germany was determined using a previously published conventional PCR using 16S-23S intergenic spacer primers (5′ CTG GGG ACT ACG GTC GCA AGA C 3′ – forward; 5′ CTC CAG TTT ATC ACT GGA AGT T 3′ – reverse). Purified amplicons were sequenced to confirm genus and species. Associations between rickettsial infections, and feline immunodeficiency virus (FIV), as well as feline leukemia virus (FeLV) status were evaluated. Rickettsial prevalence was 0.4% (2/479; CI: 0.01–1.62%). In the two infected cats, Anaplasma phagocytophilum DNA was amplified. These cats came from different environment and had outdoor access. Both were ill with many of their problems likely related to other diseases. However, one cat had neutrophilia with left shift and the other thrombocytopenia potentially caused by their A. phagocytophilum infection. There was no significant difference in the FIV and FeLV status between A. phagocytophilum-negative and -positive cats. A. phagocytophilum can cause infection in cats in Southern Germany, and appropriate tick control is recommended.     

Canine parvovirus infections in a colony of dogs

A serological study of canine parvovirus (CPV) infections in a colony of dogs was conducted over a period of 8 months. Twenty-two of 24 adult dogs sampled initially had significant antibody titres to CPV. Nine litters of puppies wer e bled at fortnightly intervals and the sera tested for antibodies to CPV. Twenty-nine of 35 natural CPV infections observed were subclinical. A puppy in one litter developed vomiting and diarrhoea during the same period as seroconversion to CPV. Four puppies from a further litter developed histologically confirmed myocarditis. Serological testing of this latter litter indicated that the virus infections occurred between 2 weeks prior to and 1 week post whelping, and that clinical disease developed 20–40 days after viral infection. The mean half life of the decline of passively derived immunity to CPV was 8.3 days.     

Canine pruritus: an approach to diagnosis. Stage II. Infestations and infections*

This series of three papers describes a straight forward, systematic approach to the investigation of canine pruritus. Those dermatoses which regularly present with this symptom are discussed, with emphasis being placed on clinical signs, diagnosis and differential diagnosis. This second paper details the parasitic infestations and bacterial and clinically similar conditions which may result in pruritus.     

Canine isosporosis - epidemiology of field and experimental infections

Isospora spp. are the causative agents of canine isosporosis. Of the 3590 diagnostic samples from Austrian dogs (< or = 2 years old), 8.7% contained Isospora oocysts, 78% of which from dogs up to 4 months of age. Non-haemorrhagic and haemorrhagic diarrhoea were significantly more prevalent in Isospora-infected animals than in coccidia-negative ones. Twelve of 15 litters from a large commercial dog breeding unit (examined from the third to the 10th week of life) also excreted Isospora (average prevalence: 36.4%) in intensities from 333 to 35,000 oocysts per gram of faeces (opg). In experimental trials 26 3-week-old Beagle puppies were infected with low (600-6000), medium (10,000) or high (20,000) dose of Isospora ohioensis-group or Isospora canis field isolates. Additionally 21 puppies were infected as above and treated with a symmetrical triazintrione. Parasitological and clinical parameters were examined. The two Isospora species differed significantly concerning intensity and duration of excretion. The pre-patent period was 6-7 days for I. ohioensis and 10-12 days for I. canis. The latter species showed significantly longer excretion and higher opg. This was not influenced by simultaneous infections with both species. Individual patterns of faecal consistency were very variable, irrespective of the infection dose. Treatment significantly reduced both the intensity and the duration of oocysts excretion as well as diarrhoea in comparison with the infected, untreated group and thus proved to be effective against coccidiosis in experimental infections.     

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 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 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 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 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 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.