The occurrence and significance of Chlamydia psittaci and Coxiella burnetii in dogs and cats. A study of the literature

With this review of the literature it is demonstrated that not only infections with Chl. psittaci and C. burnetii do occur in dogs and cats in the Federal Republic of Germany but also clinical diseases caused by these agents may occur. Especially in diseases with uncharacteristic symptoms both bacteria have to be taken into consideration as causative agents. Since both agents cause zoonotic infections a correct diagnosis is of special importance, especially if the owner of a diseased dog or cat or members of his family show signs of disease also. In cases of unidentified disease or of a rickettsial zoonosis identification of the causative agent must be tackled by cultural or serological investigation. Direct or cultural identification is often not possible so that serological techniques have to be applied. Besides established serological techniques sensitive enzyme immunoassays are useful tools for securing a diagnosis.     

Spotted fever group rickettsiae: a brief review and a Canadian perspective

Spotted fever group rickettsioses (SFGR) are infections caused by established and emerging human pathogens worldwide. These rickettsial agents are transmitted to humans via arthropods and may result in mild to severe and potentially fatal diseases. Spotted fever group rickettsioses are characterized by similar clinical features, including fever, rash, headache and myalgias, with the development of an inoculation eschar in many, but not all cases. Endemic rickettsial infections do occur but are infrequent in Canada, in contrast to the United States, where these infections are far more prevalent. Travel-associated rickettsioses, however, are being diagnosed with increasing frequency in Canadian travellers returning from international trips abroad, in particular in travellers returning from Africa. The diagnosis of rickettsial infections can be challenging owing to the non-specific nature of the clinical symptoms and the requirement for specialized testing. Serology cannot distinguish between the approximately 20 spotted fever group rickettsial species currently known or suspected to be capable of causing human infection. Molecular testing is required to determine the rickettsial species responsible for infection, but requires greater effort on the part of the clinician to collect appropriate samples, including cutaneous skin swabs from under the eschar or skin punch biopsies of the eschar or rash. Infections with spotted fever group rickettsiae likely occur more commonly than currently recognized and should be considered in patients with appropriate symptoms and exposure histories.     

Diagnosis of rickettsial diseases in dogs and cats

Rickettsial agents, including those in the genera Anaplasma, Ehrlichia, Neorickettsia, and Rickettsia, are important and common vector‐borne pathogens of dogs and cats. Disease induced by these organisms ranges from clinically inapparent to severe and potentially fatal. However, laboratory confirmation of a rickettsial etiology can be complicated by a number of factors, including the wide spectrum of disease induced by these organisms, an often low and widely fluctuating level of organism present in infected animals, cross‐reactions on serologic and molecular assays, and the presence of co‐infections. Correct diagnosis is most likely to be reached when multiple diagnostic strategies, including careful microscopic examination of stained blood films or tissues, both specific and broad serologic tests, and a suite of molecular detection assays, are used in concert. Accurate interpretation of diagnostic tests requires awareness of the likelihood for multiple agents, including novel organisms, to be responsible for the results seen in a given patient. This review provides an overview of current strategies used to diagnose rickettsial infections in dogs and cats.     

Fungal infections of the central nervous system in the dog and cat

Fungal infections of the central nervous system (CNS) in dogs and cats are uncommon. The purpose of this paper is to review the clinical signs, diagnostic tests, and therapeutic options of fungal infections of the CNS in the dog and cat. Clinical signs are dependent on lesion location and are often multifocal. Extraneural involvement is common. Antemortem diagnosis can be difficult and is definitively made via cytology, biopsy, or culture of an affected organ or cerebrospinal fluid (CSF). Magnetic resonance imaging can support a diagnosis and may assist in therapeutic decisions. Fungal serology can support a diagnosis when direct visualization of the organism is not possible. Long-term azole maintenance therapy is suggested to enhance survival and prevent relapse. Serial cerebrospinal fluid evaluation and magnetic resonance imaging may identify early relapse.     

Fanconi syndrome in four non-basenji dogs exposed to chicken jerky treats

Four small-breed dogs were diagnosed with acquired Fanconi syndrome. All dogs ate varying amounts of chicken jerky treats. All dogs were examined for similar clinical signs that included, but were not limited to, lethargy, vomiting, anorexia, diarrhea, and altered thirst and urination. The quantity of chicken jerky consumed could not be determined; however, based on the histories obtained, the chicken jerky treats were a significant part of the diet and were consumed daily by all dogs. Extensive diagnostic testing eliminated other causes of the observed clinical signs, such as urinary tract infection and rickettsial disease. Glucosuria in the face of euglycemia or hypoglycemia, aminoaciduria, and metabolic acidosis confirmed the diagnosis of Fanconi syndrome. All dogs received supportive care, including IV fluids, antibiotics, gastroprotectants, and oral nutritional supplements. Three dogs exhibited complete resolution of glucosuria, proteinuria, and the associated azotemia; however, one dog remained azotemic, resulting in a diagnosis of chronic kidney disease.     

Testing for occult heartworm infection

Heartworm infection in dogs is endemic in southern Ontario but occurs only sporadically throughout the remainder of Canada. The disease may either be associated with microfilariae in the patient's blood, a patent infection, or it may be occult. This paper describes a case of occult dirofilariasis in a dog, with emphasis on the diagnosis. A patent infection could be missed if the clinician tests an insufficient amount of blood. He should perform multiple concentration tests using either the modified Knott's technique or a filtration method. Occult infections occur in prepatent or unisexual infections, when the worms become sterile following therapy, or when the host produces antibodies that result in the destruction of the microfilariae. The recent release of a kit which detects the presence of antibodies to the adult heartworms now enables veterinarians to make an accurate diagnosis in the vast majority of dogs.     

Treatment of demodicosis in dogs: 2011 clinical practice guidelines

Background and Objectives – These guidelines were written by an international group of specialists with the aim to provide veterinarians with current recommendations for the diagnosis and treatment of canine demodicosis. Methods – Published studies of the various treatment options were reviewed and summarized. Where evidence in form of published studies was not available, expert consensus formed the base of the recommendations. Results – Demodicosis can usually be diagnosed by deep skin scrapings or trichograms; in rare cases a skin biopsy may be needed for diagnosis. Immune suppression due to endoparasitism or malnutrition in young dogs and endocrine diseases, neoplasia and chemotherapy in older dogs are considered predisposing factors and should be diagnosed and treated to optimize the therapeutic outcome. Dogs with disease severity requiring parasiticidal therapy should not be bred. Secondary bacterial skin infections frequently complicate the disease and require topical and/or systemic antimicrobial therapy. There is good evidence for the efficacy of weekly amitraz rinses and daily oral macrocyclic lactones such as milbemycin oxime, ivermectin and moxidectin for the treatment of canine demodicosis. Weekly application of topical moxidectin can be useful in dogs with milder forms of the disease. There is some evidence for the efficacy of weekly or twice weekly subcutaneous or oral doramectin. Systemic macrocyclic lactones may cause neurological adverse effects in sensitive dogs, thus a gradual increase to the final therapeutic dose may be prudent (particularly in herding breeds). Treatment should be monitored with monthly skin scrapings and extended beyond clinical and microscopic cure to minimize recurrences. Editor’s Note – A brief review article by R. Mueller has been published: Evidence‐based treatment of canine demodicosis, Tierarztl Prax Ausg K Kleintiere Heimtiere 2011; 39: 419–24. This is not considered to constitute duplication of the article published here in Veterinary Dermatology.     

Development and evaluation of an enzyme-linked immunosorbent assay for the serodiagnosis of pythiosis in dogs

Pythiosis (caused by the aquatic oomycete Pythium insidiosum) is a devastating and often fatal cause of either severe transmural gastroenteritis or locally invasive subcutaneous disease in dogs living in the southeastern United States. Although early diagnosis is essential for successful treatment, tools available for this task are limited. Therefore, we developed and evaluated an enzyme-linked immunosorbent assay (ELISA) for the detection of anti-P insidiosum antibodies in canine serum. A soluble mycelial extract of P insidiosum was utilized as antigen in the ELISA, which was used to evaluate serum from 43 dogs with pythiosis, 8 dogs with lagenidiosis (another canine oomycosis), 16 dogs with nonoomycotic fungal or algal infections, 22 dogs with nonfungal gastrointestinal or skin disease, and 55 healthy dogs. Results were expressed as percent positivity (PP) relative to a strong positive control serum run on each plate. Medians and ranges for each of the 5 groups were as follows: pythiosis (81.7%, 50.6-98.5%), lagenidiosis (17.3%, 11.3-29.2%), other fungal or algal infections (8.2%, 4.7-15.4%), nonfungal gastrointestinal or skin disease (6.2%, 3.9-20.7%), and healthy dogs (6.7%, 3.0-15.2%). When using a cutoff value of 40% PP, the sensitivity and specificity of the ELISA both were 100%. In addition, ELISA values measured after successful surgical therapy in 2 dogs showed a decrease of anti-P insidiosum antibody concentrations into the normal range as early as 2 months after treatment. We conclude that the ELISA is a sensitive and specific test for the diagnosis of canine pythiosis, and may be a useful tool for monitoring response to medical or surgical therapy.     

Travel medicine of parasitic diseases in the dog

Companion animals are increasingly brought along by their owners to foreign countries. Thus, small animal travel medicine is becoming more important. The field includes both prophylaxis and metaphylaxis against various infectious diseases, as well as their diagnosis and treatment. Dogs returning from Southern Europe, but also from more tropical regions, may be infected with exotic pathogens. In addition, imported pedigree or working dogs, and especially stray dogs imported through welfare organisations, are at high risk.The present overview summarises the clinical and practical aspects of exotic parasitic diseases that may affect such dogs, and the risk of such diseases becoming autochthonously transmitted in Switzerland. Furthermore, the zoonotic potential of these infections will be considered.     

Canine Ehrlichiosis (tropical canine pancytopenia): A review

Tropical canine pancytopenia (TCP), a disease of dogs caused by the rickettsial agent, Ehrlichia canis, is being recognized with increased frequency in many parts of the world. The brown dog tick, Rhipicephalus sanguineus, is an efficient vector of E. canis and transstadial transmission occurs. Infections persist and are characterized by rising antibody titers and hypergammaglobulinemia. Dogs cleared of infection with tetracycline are fully susceptible to reinfection with the homologous strain of E. canis and often develop severe disease. Experimental infections in beagle and German shepherd dogs have shown that severity of disease is related to the breed of dog. German shepherd dogs often develop a severe hemorrhagic syndrome 60 or more days following infection. Recent studies have shown that bone marrow hypoplasia is important in the pathogenesis of severe chronic TCP. Differences in response to infection may reflect underlying immunological defects, particularly in the cell-mediated system.     

Feline aelurostrongylosis and canine angiostrongylosis: a challenging diagnosis for two emerging verminous pneumonia infections

Aelurostrongylus abstrusus and Angiostrongylus vasorum (Nematoda, Metastrongyloidea) are causative agents of verminous feline and canine pneumonia. Both are presently emerging in several geographical areas and are of major clinical importance. Given the range of parasitic and non-parasitic pathogens which may cause cardio-respiratory distress in dogs and cats, the unequivocal specific diagnosis of both diseases is pivotal for unravelling their epidemiology and central to therapy and control. Several conventional clinico-pathologic, diagnostic imaging and parasitological approaches are currently used in practice, but all have major limitations in the specific diagnosis of these diseases. Serological methods have shown promise in the diagnosis of A. abstrusus and A. vasorum infections, but no clinically useful tests are currently available. Additionally, there have been major advances in the development of novel molecular diagnostic tools for feline aelurostrongylosis, but efforts to develop molecular diagnostic tests are still preliminary for angiostrongylosis. This article provides a review of A. abstrusus and A. vasorum infections in cats and dogs, focusing on the advantages and shortcomings of classical diagnostic methodologies and on present diagnostic advances as well as future perspectives instrumental to epidemiological and clinical studies.     

Ciclosporin use in multi-drug therapy for meningoencephalomyelitis of unknown aetiology in dogs

OBJECTIVE: To evaluate the efficacy and safety of ciclosporin therapy alone or in combination with corticosteroids and/or ketoconazole in dogs with diagnosis of meningoencephalomyelitis of unknown aetiology. METHODS: Medical records of 10 dogs diagnosed with meningoencephalomyelitis of unknown aetiology and treated with ciclosporin therapy alone or in combination with corticosteroids and/or ketoconazole were reviewed at the Veterinary Medical Teaching Hospital, University of Wisconsin-Madison. Laboratory abnormalities, side effects, clinical and cerebrospinal fluid responses to treatment and association between blood ciclosporin level and response to treatment were evaluated. Histopathological diagnosis was available in three patients. RESULTS: No significant abnormalities were detected on serial complete blood count and serum chemistry panel in any of the dogs. Side effects of ciclosporin therapy included excessive shedding, gingival hyperplasia and hypertrichosis. Overall median survival time for all dogs in the study was 930 days (range, 60 to more than 1290 days). In all dogs, serial cerebrospinal fluid analysis showed a marked improvement in the inflammation. CLINICAL SIGNIFICANCE: Results suggest that ciclosporin either alone or in combination with ketoconazole may be a safe and effective treatment for meningoencephalomyelitis of unknown aetiology in dogs.     

PRIMARY IRRADIATION OF CANINE INTRACRANIAL MASSES

Twenty-nine dogs received primary radiation therapy for intracranial lesions and clinical signs suggestive of neoplasia. Presumptive diagnosis and tumor categorization was based on computed tomographic or magnetic resonance images. Meningioma was the most likely tumor type in 22 dogs and glioma or choroid plexus tumors were tentatively identified in 4 and 3 dogs, respectively. Cobalt-60 radiation was delivered in 3 Gy fractions on a daily, Monday-through-Friday basis for a total dose of 48 Gy (16 fractions) in 28 dogs; one dog received 54 Gy. Two of 29 dogs died during treatment of signs suggestive of progressive tumor growth but were included in the overall evaluation of response to treatment. Median overall survival was 250 days (range 21-804). Mild acute radiation effects on normal tissue developed and did not influence outcome in any dog. Late radiation effects could not be evaluated in this study. No significant predictive indicators were identified from the clinical or imaging data. Radiation therapy is superior to medical treatment of brain tumors in dogs with steroids, is useful for tumors that are not currently operable and may be preferable to surgical resection in dogs if the mass appears infiltrative. However, 22/29 (76%) dogs died of recurrent progressive neuropathy suggestive of tumor regrowth or progression. Thus, alternative methods for delivery of radiation to dogs with brain tumors or novel combinations of therapy should continue to undergo evaluation.     

Thoracic, Abdominal and Vertebral Actinomycosis

The clinical, laboratory, radiographic, and histologic features and the response to therapy in three dogs with actinomycosis are reported. One dog (dog 1) had a 12-cm nonresectable mass extending from the ventrolateral chest wall into the left ventricular myocardium. Another dog (dog 2) had a diffuse peritonitis with "sulfur granules" and two large masses. One of these masses was nonresectable involving adjacent abdominal structures. A third dog (dog 3) had a subvertebral mass at T1-3 producing quadraplegia. Two dogs had periosteal reactions involving adjacent sternebrae (dog 1) or ribs and vertebral bodies (dog 3) that are characteristic of Actinomyces spp infections. In dogs 1 and 2 the diagnosis was based on the morphologic and tinctorial properties of free sulfur granules and/or tissue granules. Culture results were variable. Tissue from dog 1 yielded no growth, while polymicrobial infections, which included Actinomyces spp, were identified in dogs 2 and 3. Actinomyces odontolyticus was isolated from dog 3. Although the actinomycotic granulomas were either not excised or only partially excised from dogs 1 and 2, both animals were cured by the oral administration of high doses of penicillin G for 19 and 6 months, respectively. Dog 3 responded dramatically to the same antibiotic therapy given for 5 months. However, within 4 months of discontinuing treatment an abscess and draining fistulous tracts developed in the left axillary region. Two surgical fistulectomies and additional penicillin therapy were required to cure this animal. These cases and the current veterinary and human literature on actinomycosis are used to propose a rational approach to the treatment of actinomycosis in the dog.     

Paraneoplastic disorders in dogs with hematopoietic tumors

Often overlooked in the presence of neoplasia, PNDs constitute significant clinical entities in dogs with hematopoietic tumors. They may cause morbidity and mortality in such patients, with effects more severe than those caused by the associated tumor. Accurate clinical evaluation of these disorders is important in differential diagnosis and treatment, for failure to realize that cancer can produce many clinical signs similar to those of other diseases may lead to incorrect diagnosis and delayed therapy. Early recognition of the problem underlying the PND is essential to selecting the proper therapeutic approach and maximizing the patient's chances for remission and survival. The presence of these disorders may complicate or rule out the preferred therapy in some cases of hematopoietic neoplasia, because the addition of cytotoxic drugs may worsen the existing PND, predisposing the dog to a variety of complications. Appropriate management of the PND may be of more immediate importance than treatment of the tumor. The study and recognition of PNDs in dogs with hematopoietic tumors may be valuable for a number of reasons: to facilitate early diagnosis of the tumor, for the observed abnormalities may represent tumor cell markers; to allow assessment of premalignant states; to aid in the search for metastases; to help quantify and monitor response to therapy; to aid in the evaluation of tumor recurrence or progression; to aid in identifying specific pathophysiologic processes by which cancer produces systemic effects; and to provide insight into the study of malignant transformation. Recognition of PNDs is relevant to the diagnosis and treatment of many problems in veterinary cancer medicine. With increasing emphasis on diagnosis and treatment of canine hematopoietic tumors, PNDs will be recognized with greater frequency and will assume greater importance in the therapeutic management of those patients. Research in veterinary and human cancer medicine needs to be directed toward identifying more definitively those substances and pathways that are responsible for PNDs, because therapy directed toward arresting the specific pathophysiologic processes causing the PND may offer the best approach for successful management of cancer.     

Clinicopathologic findings in dogs seroreactive to Bartonella henselae antigens

OBJECTIVE: To assess the potential clinical relevance of seroreactivity to Bartonella henselae antigens in dogs. ANIMALS: 40 dogs seroreactive to B henselae and 45 dogs that did not seroreact to B henselae. PROCEDURE: A case-control study was conducted. Clinical and clinicopathologic findings were extracted from medical records of each dog. RESULTS: Statistical differences were not detected between dogs seroreactive or nonseroreactive to B henselae when analyzed on the basis of disease category or results of hematologic, biochemical, urine, or cytologic analysis. However, seroreactivity to B henselae antigens was detected in 2 of 4 dogs with a clinical diagnosis of granulomatous meningoencephalitis, 3 of 4 dogs with immune-mediated hemolytic anemia, 3 of 4 dogs with infective endocarditis, 2 of 3 dogs with lymphoid neoplasia, and 5 of 10 dogs with polyarthritis. Additionally, seroreactivity to B henselae antigens was detected in 18 of 34 thrombocytopenic dogs and 14 of 27 dogs with neutrophilia. CONCLUSIONS AND CLINICAL RELEVANCE: Significant associations were not detected between seroreactivity to B henselae and various diseases. Prospective epidemiologic studies investigating specific diseases, such as meningoencephalitis or polyarthritis, and specific hematologic abnormalities, such as immunemediated hemolytic anemia or thrombocytopenia, should be conducted to further define the potential clinical relevance of antibodies against B henselae in dogs. IMPACT FOR HUMAN MEDICINE: Bartonella organisms are increasingly reported as pathogens that induce are increasingly reported as pathogens that induce chronic infections in humans and dogs. Dogs may serve as natural candidates for future study of the disease in humans.     

Ventricular systolic dysfunction in dogs diagnosed with hypoadrenocorticism

In human patients with hypoadrenocorticism, a secondary dilated cardiomyopathy is noted that has been reported to resolve with replacement steroid therapy. A similar secondary dilated cardiomyopathy in dogs with hypoadrenocorticism has not been previously described. We present three dogs concurrently diagnosed with hypoadrenocorticism and ventricular dilation with systolic dysfunction. Two dogs were presented with clinical signs consistent with biventricular congestive heart failure and a third dog was presented with signs of acute hypoadrenocorticism without congestive heart failure. All dogs recovered to normal cardiac size and function with therapy. Hypoadrenocorticism should be considered as a differential diagnosis in dogs that present with ventricular dilation and systolic dysfunction if there are other indicators in the clinical and laboratory testing. Additionally, a thorough cardiac evaluation should be recommended for dogs that are found to have a heart murmur at the time of diagnosis of hypoadrenocorticism.     

Small mammal virology.

Most viral infections in small mammals are transient and rarely produce clinical signs. When clinical signs do appear, they are often of a multifactorial etiology such as respiratory infection with Sendai virus and the bacteria M. pulmonis in rodents. Diagnosis is generally made based on clinical signs, while therapy involves treatment for concurrent bacterial infections and supportive care. Small mammals may carry zoonotic viruses such as LCMV, but natural infections are uncommon. Viral diseases are rare (or largely unknown) for hedgehogs, chinchillas, and prairie dogs, while no known naturally occurring, clinically relevant viral diseases exist for gerbils and sugar gliders. This article is intended to aid the clinician in identifying viral infections in small mammals and to help determine the significance each virus has during clinical disease.     

Chronic tracheobronchial disease in the dog.

Tracheobronchial collapse and chronic bronchitis (CB) are the two most common forms of chronic tracheobronchial disease in dogs. These conditions may exist independently of one another, although CB and some degree of tracheobronchial collapse often co-exist in the same patient. Diagnosis of CB can be established on clinical grounds alone, whereas radiographic or bronchoscopic evidence is required to confirm the diagnosis of tracheobronchial collapse. Although glucocorticoid drug therapy remains one of the most effective methods for managing CB, surgical implantation of a prosthetic airway device may be of great benefit for some dogs with a focal area of collapsing trachea. With early diagnosis and aggressive medical and surgical management, the prognosis for many dogs with chronic tracheobronchial disease is good for reasonable quality of life.