Itamar Aroch

Transmission of hepatozoon canis to dogs by naturally-fed or percutaneously-injected Rhipicephalus sanguineus ticks.

Hepatozoon canis is an apicomplexan protozoan parasite of dogs, prevalent in Asia, Africa, and southern Europe. Experimental transmission of H. canis to dogs was performed with laboratory-reared Rhipicephalus sanguineus nymphs that fed on a naturally infected dog or were percutaneously injected with canine blood containing H. canis gamonts. Dogs were inoculated by oral ingestion of adult ticks containing H. canis oocysts. Transstadial transmission of H. canis was recorded, whereas transovarial transmission could not be demonstrated. Oocysts were detected in 85% of the adult ticks that had engorged as nymphs on an infected dog and in 61% of the adult ticks resulting from nymphs injected percutaneously with blood from the same dog. Nine of 12 dogs (75%) inoculated with naturally fed or percutaneously injected ticks became parasitologically positive, and all showed seroconversion. Meronts were initially detected in the bone marrow 13 days postinoculation and gamonts 28 days after infection. The variation in the time of initial detection of parasitemia among infected dogs and the rapid appearance of gamonts in dogs immunosuppressed with corticosteroids suggest that immune mechanisms play an important role in controlling H. canis parasitism. The artificial acquisition of Hepatozoon parasites by percutaneous injection of ticks, demonstrated here for the first time, may serve as a useful tool for studies on transmission, vector–host relationships, and the immunology of infection with Hepatozoon species.

Clinical manifestations of infectious canine cyclic thrombocytopenia

This paper describes five naturally occurring clinical cases of infectious canine cyclic thrombocytopenia that were the first serologically confirmed cases of Ehrlichia platys infection in Israel. In the USA this disease is considered subclinical, but the dogs in this study developed distinct clinical abnormalities. The signs observed by the owners included anorexia, lethargy, depression, weight loss and a mucopurulent nasal discharge. The principal findings on physical examination included lymphadenomegaly, pale mucous membranes, fever and the presence of ticks. The main abnormal haematological and biochemical findings included thrombocytopenia, the presence of giant platelets, low haematocrit, monocytosis and low albumin concentrations. All five dogs were less than two years of age, and four were purebred dogs, suggesting that these two factors may be associated with increased risk to infection and clinical disease. Two of the dogs were seropositive to E canis, a finding which is compatible with other reports, and which confirms that combined infections of E platys and E canis are common; it also suggests that E canis infections may contribute to the pathogenesis of E platys. The distinct clinical manifestation of the disease in these five dogs suggests that there may be a different, more virulent strain of E platys in Israel.

Canine spirocercosis: clinical, diagnostic, pathologic, and epidemiologic characteristics

The nematode Spirocerca lupi is a parasite of dogs with beetles of several species serving as intermediate hosts. The medical records of 50 dogs diagnosed with spirocercosis at the Hebrew University Veterinary Teaching Hospital (HUVTH) in Israel during 1991-1999 were retrospectively reviewed and compared to a control group (n=100). There was a seven-fold increase in the annual number of dogs diagnosed with spirocercosis during these years while the hospital caseload increased by 80%, indicating an emerging outbreak of this infection. Dogs from the greater Tel Aviv area were at the highest risk of being diagnosed with spirocercosis with 74% of the cases originating from this region compared to only 17% of the controls. The disease appeared to have a primarily urban pattern of distribution with a significantly higher percentage (P=0.025) of dogs from cities versus rural areas, as compared to the control group. Sixty-two percent of the cases were diagnosed during the colder months of December through April. The median age of infected dogs was 5 years, with dogs 1 year old or younger at the lowest risk of being diagnosed with spirocercosis. Large breeds were at a higher risk of infection in comparison to small breeds and the Labrador Retriever was significantly over represented (P=0.027) in the study group compared to the control population. The most common signs were vomiting or regurgitation (60%), pyrexia (24%), weakness (22%), respiratory abnormalities (20%), anorexia (18%), melena (18%) and paraparesis (14%). A caudal esophageal mass was identified by radiography in 53% of the dogs and spondylitis of the thoracic vertebrae in 33%. Fecal flotation was positive for S. lupi eggs in 80% of the dogs, and endoscopy was found to be the most sensitive diagnostic procedure and allowed diagnosis in 100% of the examined dogs. Fifty-three percent of the dogs were anemic and creatine kinase (CK) activities were elevated in 54%. Necropsy of 14 dogs revealed esophageal or gastric granulomas in 13 dogs, and an esophageal osteosarcoma in a single animal. Aortic aneurysms were found in six (43%) dogs. Out of 24, 15 dogs (63%) for which follow-up information was available died or were euthanized within 1 month of admission. The case-fatality rate decreased toward the end of the study period when improved therapy with avermectins became available.

Heat Stroke in Dogs: A Retrospective Study of 54 Cases (1999–2004) and Analysis of Risk Factors for Death

The medical records of 54 dogs presented to the Hebrew University Veterinary Teaching Hospital and diagnosed with heat stroke were retrospectively reviewed. Data abstracted included history, clinical and clinicopathological signs at admission, treatment, disease progression, and outcome. Exertional and environmental heat stroke were present in 63% (34 of 54) and 37% (20 of 54) of the dogs, respectively, and 78% (42 of 54) were examined between June and August. The mean temperature and heat discomfort index in the particular days of heat stroke were significantly increased (P < .001, P < .001, respectively) compared with their corresponding average daily values. In 27 dogs the body temperature was > or = 41 degrees C (105.8 degrees F). Belgian Malinois (15%, odds ratio [OR] = 24, 95% confidence interval [CI95%] 8.2-64.5), Golden and Labrador Retrievers (21%, OR = 2.08, CI95% 0.95-4.2), and brachycephalic breeds (25%, OR = 1.7, CI95%], 0.81-3.21) were overrepresented, whereas small breeds (<8 kg) were underrepresented (2%, OR = 0.08, CI95%, 0.002-0.48). Thrombocytopenia (45 of 54 dogs) and prolongation of the prothrombin (PT) and activated thromboplastin (aPTT) times (27 of 47 dogs) were recorded during hospitalization. Disseminated intravascular coagulation (P = .013) and acute renal failure (P = .008), diagnosed in 28 of 54 and 18 of 54 of the cases, respectively, were risk factors for death. The overall mortality rate was 50%. Hypoglycemia (<47 mg/dL, P = .003), prolonged PT (>18 seconds, P = .05), and aPTT (>30 sec, P < .001) at admission were associated with death. Serum creatinine >1.5 mg/dL (P = .003) after 24 hours, delayed admission (>90 minutes, P = .032), seizures (P = .02), and obesity (P = .04) were also risk factors for death. Heat stroke in dogs results in serious complications and high fatality rate despite appropriate treatment.

Hepatozoon species infection in domestic cats: A retrospective study

Hepatozoon sp. is a protozoan parasite of peripheral blood neutrophils in cats. Feline hepatozoonosis has been reported infrequently and little is known about the pathogenesis of this infection. In order to further clarify clinicopathological characteristics of hepatozoonosis in domestic cats, a retrospecitve study of hepatozoonosis in cats admitted during 1989-1995 to the Hebrew University School of Veterinary Medicine was conducted. The study population comprised all the cats whose medical records included a complete blood count with a microscopical examination of a blood smear during this 7-year period (n=1229). Hepatozoon gametocytes were identified in seven cats (0.57%) ranging from 1 to 6 years of age. Infected cats were mostly males (6/7) of mixed breed (5/7) with a variety of complaints and clinical signs. The clinicopathological findings included increased activities of serum lactate dehydrogenase (LDH) (5/6) and creatine kinase (CK) (5/6). The elevated enzymes detected in cats with hepatozoonosis are suggestive of muscular damage. Sixty-seven percent (4/6) of the cats with hepatozoonosis which were tested for a retroviral disease were found infected either in FIV or FELV. In addition, 2/7 cats were co-infected with Hemobartonella felis. In conclusion, parasitemia with Hepatozoon sp. is a rare finding in cats from Israel. The over-representation of cats with a retroviral disease among the cats with hepatozoonosis indicates a possible association between immunosupression and the development of Hepatozoon infection.

Retrospective study of 46 cases of feline haemobartonellosis in Israel and their relationships with FeLV and FIV infections

Forty-six cats with clinical haemobartonellosis were studied; 75 per cent of the cats of known age were two-and-a-half years old or younger, 50 per cent were intact males and 19.5 per cent were castrated males. The predominant signs of the disease were tachypnoea, lethargy, depression, anorexia, infestation with fleas, pale mucous membranes, icterus, emaciation, dehydration, splenomegaly, anaemia, leucocytosis, increased activities of alanine aminotransferase and aspartate aminotransferase, and azotaemia. Thirty-eight per cent of the cats that were tested for feline leukaemia virus (FeLV) antigen were positive, and 22 per cent of those tested for feline immunodeficiency virus (FIV) antibodies were positive. The prevalence of both FeLV and FIV was much higher than in the general Israeli cat population. The cats infected with both Haemobartonella felis and FeLV had a significantly lower body temperature, were more anaemic and the mean cell volume of their erythrocytes was greater than in the cats with haemobartonellosis alone.

Evaluation of doramectin for the treatment of experimental canine spirocercosis.

The nematode Spirocerca lupi is primarily a parasite of dogs, which causes typical lesions of esophageal nodular granulomas, aortic aneurysms and spondylitis. In order to evaluate the therapeutic effect of doramectin on experimental canine spirocercosis, seven beagle dogs experimentally infected with 40 infectious S. lupi larvae (L(3)) were treated with doramectin. Treatment was commenced following endoscopic visualization of esophageal granulomas, and typical S. lupi eggs were detected in the feces. The treatment protocol included six treatments of doramectin (400 microg/kg subcutaneously) at 2 weeks intervals, followed by monthly injections until the disappearance of the esophageal granulomas or the end of the study (768 days post-inoculation). Eggs could not be found on fecal examinations 3-10 days after the first or second doramectin treatment. In addition, a gradual decrease in size of granulomas was noticed in all seven dogs during the course of the study. Esophageal granulomas had completely resolved in six of the seven dogs between day 35 and day 544 post-initial doramectin treatment, by day 35 in one dog (after three treatments), by day 43 in two dogs (after four treatments), by day 98 in one dog (after seven treatments), by day 460 in one dog (after 18 treatments) and by day 544 in another dog (after 21 treatments). In one dog, remnants of S. lupi granulomas could still be seen 544 days post-initiation of treatment with doramectin. Multiple subcutaneous injections of doramectin (400 microg/kg) were shown to be effective and safe in the treatment of canine spirocercosis.

Investigation of splenic functions in canine monocytic ehrlichiosis

In order to determine the role of the spleen in the pathogenesis of canine monocytic ehrlichiosis (CME), the effect of splenectomy on the course of the acute phase of experimental was investigated. Intact and splenectomized dogs, sero-negative for Ehrlichia canis antibodies, were infected with the Israeli strain of E. canis. Serology, clinical signs and haematological parameters were recorded prior to infection, and over a period of 60 days post infection, and were compared between the intact and the splenectomized dogs. All dogs seroconverted for IFA E. canis antibodies by days 10 to 17 post infection. There did not appear to be any difference in the day of appearance or in the titer of anti-E. canis IgG antibodies, between the splenectomized and intact groups throughout the course of the study. During the acute stage, food consumption (percentage change) was significantly lower in the intact group compared to the splenectomized group (-66.3% and -25.3%, respectively, p < 0.0001). During this period, significant higher body temperatures were measured in the intact group (average of 39.76 degrees C vs. 38.96 degrees C, p < 0.0001). The haematocrit, red blood cell counts, haemoglobin concentrations and platelet counts were significantly lower (p < 0.05) in the intact group when compared to the splenectomized group during the whole course of the study. The clinical and the haematological findings in our study suggest that the disease process was milder in the splenectomized dogs compared to the intact dogs. The results of this study suggest that the spleen plays an important role in the pathogenesis of CME. Splenic inflammatory mediators and/or other splenic substances, are proposed to play a key role in the pathogenesis of the disease. Our results further substantiate the involvement of immune mechanisms in the pathogenesis of CME.

Pathological Findings in Dogs with Fatal Heatstroke

Eleven dogs with fatal heatstroke were examined grossly and histopathologically post mortem. All showed multi-organ haemorrhagic diathesis with coagulative necrosis. Hypaeremia and diffuse oedema were observed in the skin (eight dogs), lungs (11), brain (11) and bone marrow (one). Congestion of the splenic pulp (10 dogs) and hepatic sinusoids (nine) was also noted. Necrosis was observed in the mucosa of the small intestine (seven dogs), large intestine (eight), renal tubular epithelium (nine), hepatic parenchyma (eight) and brain neural tissue (four). The results showed that naturally occurring, fatal canine heatstroke induces acute multiple organ lesions affecting most body systems, and suggest that the more prevalent lesions include haemorrhagic diathesis, microthrombosis and coagulative necrosis. These are probable sequels of hyperthermia-induced disseminated intravascular coagulation and systemic inflammatory response syndrome, which lead to multi-organ dysfunction and death.

Doramectin toxicity in a collie

the penis may have damagcd the erectile bodies and the pudendal nerves. Musth-related causes xvere not involvcd. Penile paralysis following administrationi of phenothiazinederivative tranquillisers (acetylpromazine) has been reported in an Asian circus elephant (Kuntze and Kuntze 1991). However, this possibility could be excluded, as these tranquillisers were not available in this rural area of Vietnaimi. The therapy was painful and could have become extremely dangerous, but nmost of the standard anaesthetic drugs, such as xylazine or phenothiaziie-derivative tranquillisers, potentially compounid penile protrusion (Turner and others 1995, Silinski and others 2002). Additionally, the duration and frequeincy of treatmeint prevented the routine use of sedation. Due to the prolonged state of the priapism, the prognosis was poor. Stallions wvith persistent penile protrusions are unlikely to regain the ability to retract the penis or to achieve erection again (Schumacher and Varner 1999). In human beings, irreversible cavernosal damage begins 1 2 to 24 hours after the onset of priapism (Rochat 2001). In the elephant, a surgical procedure appeared to be justified; however, the lack of infrastructure, electricity, medical supplies and hygiene prevented any invasive treatment. Alternative medical treatmenits, such as the use of cholinergic blockers, diuretics and the irrigation of the cavernous tissue with heparinised lactated Ringers solution, which are described in stallions (Wilson and others 1991), were also unavailable. The systemic administration of antibiotics wvas considered but, due to the expected vascular stasis, antibiotics were only administered topically.