Clinical and pathological findings in feline immunodeficiency virus experimental infection.

A study is described of the clinical and pathological findings in 20 specific pathogen free cats infected when 1 year old with feline immunodeficiency virus and monitored over 12 months. Cats were divided into two groups (A and B). The clinical and clinicopathological features were studied in Group A. In Group B, at 1, 2, 4, 9 and 12 months post infection two cats were necropsied. Clinically all cats developed generalised lymphadenopathy, six cats were neutropenic and five cats lymphopenic. Three cats became febrile with conjunctivitis and anterior uveitis and one of these cats ultimately developed jaundice. Postmortem examinations confirmed a generalised lymphadenopathy involving peripheral and visceral lymph nodes with concurrent stimulation of splenic white matter and mucosal lymphoid tissue of the digestive tract and conjunctiva. Within the lymph nodes there was a reactive follicular hyperplasia accompanied by a paracortical hyperplasia with an increased paracortical vascularity. Unusual features were the presence of lymphoid follicles in the bone marrow, thymus and parathyroid tissue. In addition, aggregates of lymphoid cells were found within salivary glands, kidneys, sclera and choroid of the eye. One cat developed a lymphosarcoma affecting the liver and kidneys at 36 weeks post infection. The cat with jaundice had a cholangitis with marked biliary epithelial hyperplasia.     

Babesia gibsoni infection in three dogs in Victoria

Small intraerythrocytic parasites were observed in the blood of three related male American Pit Bull Terriers. Two of the dogs, both less than 1-year-old, were anaemic at the time of initial examination and the third, an adult and sire of the two younger dogs, had a normal haemogram and low parasitaemia. The morphological appearance of the erythrocyte inclusions, analysis of a 450-bp region of the 18S rRNA gene and antibody titres provided evidence that this parasite was Babesia gibsoni, a species not previously reported in Australia.     

Molecular survey of Babesia infection in dogs in Okinawa, Japan

A total of 80 free-roaming dogs on Okinawa Island, Japan, were examined for Babesia infection using the polymerase chain reaction (PCR) and sequence analysis. Of 80 samples, 12 were positive in a Babesia genus-specific PCR. Consequent species-specific PCR for B. canis and B. gibsoni revealed that 5 (6.3%) and 7 (8.8%) dogs were infected with B. canis and B. gibsoni, respectively. Sequence analysis of the PCR products revealed that the 18S rRNA gene sequence of B. canis detected from dogs in Okinawa was very close to B. canis vogeli with sequence similarity of 99.94%.     

Epidemiological survey of Babesia gibsoni infection in dogs in eastern Japan

To determine the distribution of Babesia gibsoni infection in dogs in the eastern part of Japan, an epidemiological survey of dogs suspected of having B. gibsoni infection was attempted using the polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Thirty-five of 115 such dogs (30.4%) were positive by PCR and/or ELISA. The 35 positive dogs consisted of 28 Tosa dogs, 4 American Pit Bull Terriers, and 3 mongrel dogs in Aomori, Fukushima, Ibaraki, Gunma, Chiba, Tokyo, Kanagawa, and Nagano Prefectures. The positive dogs had a significantly lower rate of tick exposure and a higher rate of bites by other dogs. Twenty-two of 35 B. gibsoni-positive dogs were infected with hemoplasma, and the rate of infection was significantly higher than that of B. gibsoni-negative dogs.     

Babesia gibsoni infection among dogs in the southeastern United States

OBJECTIVE: To identify subclinical Babesia gibsoni infection in American Pit Bull Terriers from the southeastern United States and to determine the genetic sequence of parasite DNA isolated from these dogs. DESIGN: Case series. ANIMALS: 33 American Pit Bull Terriers and 87 dogs of various other breeds. PROCEDURE: Blood smears were examined for microscopic evidence of the parasite, and DNA was extracted from blood samples and used in a polymerase chain reaction (PCR) assay designed to amplify the small subunit ribosomal RNA gene sequence of B. gibsoni. Amplification products of the expected size were sequenced, and sequences were compared with published sequences for B. gibsoni isolates. Hematocrit, platelet count, mean platelet volume, WBC count, and eosinophil count were compared between dogs with positive PCR assay results and dogs with negative results. RESULTS: Results of the PCR assay were positive for 18 of the 33 (55%) American Pit Bull Terriers, including all 10 dogs with microscopic evidence of parasitemia. Only 1 of these dogs was clinically ill at the time blood samples were collected. Results of microscopic evaluation of blood smears and of the PCR assay were negative for the 87 other dogs. Hematocrit and platelet count were significantly lower in dogs with positive PCR assay results than in dogs with negative results. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that American Pit Bull Terriers in the southeastern United States may be subclinically infected with B. gibsoni. However, subclinical infection was not identified in dogs of other breeds from the same geographic area.     

Hemolytic anemia caused by Babesia gibsoni infection in dogs.

Babesia gibsoni caused severe hemolytic anemia in 11 dogs from southern California. The most common clinical signs of B gibsoni infection were lethargy, anorexia, anemia, and thrombocytopenia. Acute infection with B gibsoni may be misdiagnosed as autoimmune hemolytic anemia. Diagnosis was most reliably determined by identification of the intraerythrocytic parasites on Giemsa-stained blood smears. The pathogenicity of B gibsoni, difficulties in diagnosis, the parasite's resistance to treatment with available drugs, and frequent interstate movement of dogs indicate that this disease may be a serious threat to dogs throughout the United States.     

Increased erythrophagocytic activity of macrophages in dogs with Babesia gibsoni infection

To elucidate the mechanism of anemia caused by Babesia gibsoni infection in dogs, the erythrophagocytic activity of macrophages in infected dogs was investigated in vitro. In the present study, macrophages obtained from peripheral blood (PB-macrophages) and bone marrow (BM-macrophages) of splenectomized dogs with chronic B. gibsoni infection were examined. The BM-macrophages in the splenectomized dogs with chronic babesiosis exhibited an increased erythrophagocytic activity compared with those from splenectomized, non-infected dogs. In the infected dogs, erythrophagocytic activities of macrophages against both auto- and iso-erythorcytes from normal dogs were almost the same. Administration of an anti-protozoal drug, diminazene diaceturate, resulted in a decrease of the erythrophagocytic activity of BM-macrophages associated with an increase of the hematocrit value in splenectomized dogs with chronic babesiosis. In splenectomized dogs with acute babesiosis, erythrophagocytic activity of BM-macrophages was also elevated. Such a phenomenon was not, however, observed in splenectomized dogs with onion-induced hemolytic anemia. These results suggest that the erythrophagocytic ability of macrophages in the infected dogs might be accelerated by parasites per se through an unknown mechanism, resulting in severe anemia in spite of low parasitemia.     

Clinical and hematologic effects of experimental infection of dogs with recently identified Babesia gibsoni-like isolates from Oklahoma

OBJECTIVE: To characterize clinical and hematologic responses in dogs following experimental inoculation with Babesia gibsoni-like isolates from infected dogs in Oklahoma. DESIGN: Prospective study. ANIMALS: 6 mixed-breed dogs. PROCEDURE: 2 dogs were inoculated with organisms from a naturally infected dog, and 3 were inoculated with organisms from a second naturally infected dog (1 of these 3 dogs was splenectomized 1 week prior to inoculation). One dog was not inoculated. Complete blood counts were performed weekly. RESULTS: In the 5 dogs inoculated with organisms, parasites were initially detected 1 to 5 weeks after inoculation, and severity of parasitemia peaked with 1.9 to 6.0% of RBC infected by 4 to 6 weeks after inoculation. Parasitemia was easily detectable (> 0.1% of RBC infected) for 3 to 4 weeks. Clinical abnormalities included lethargy, fever, and pale mucous membranes but were mild to nearly inapparent in 2 dogs. All dogs developed regenerative anemia and marked thrombocytopenia. Thrombocytopenia developed before and lasted longer than the parasitemia. Profound but transient neutropenia was detected in some dogs. The splenectomized dog developed more severe parasitemia and anemia and more pronounced clinical abnormalities. Three dogs with intact spleens recovered without treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that 2 or more genotypically distinct, but morphologically identical, small Babesia parasites can infect dogs in the United States. Compared with infection with small Babesia parasites from California, infection with these isolates resulted in less severe parasitemia and clinical abnormalities. Parasitemia was transient, indicating that identification of organisms in blood smears may be difficult in some dogs.     

Plasma insulin concentrations in hypoglycaemic dogs with Babesia canis rossi infection

Hypoglycaemia has been identified as a life-threatening metabolic complication in almost 20% of severely ill dogs suffering from babesiosis due to Babesia canis rossi infection, and has been correlated with mortality. Hyperinsulinaemia as a result of inappropriate insulin secretion may precipitate hypoglycaemia, and has been suggested as a possible cause of hypoglycaemia in human and murine malaria. This prospective, cross-sectional, observational study, including 94 dogs with naturally occurring virulent babesiosis, sought to identify the presence of inappropriate insulin secretion in hypoglycaemic canine babesiosis. Pre-treatment jugular blood samples were collected for simultaneous determination of plasma glucose and insulin concentrations. Animals were retrospectively divided into three groups: hypoglycaemic (BG<3.3 mmol/L; n=16), normoglycaemic (BG 3.3-5.5 mmol/L; n=62), and hyperglycaemic (BG>5.5 mmol/L; n=16). The median insulin concentrations for the hypoglycaemic, normoglycaemic, and hyperglycaemic groups were 10.7 pmol/L, 10.7 pmol/L, and 21.7 pmol/L, respectively. Statistical analysis revealed no significant difference in insulin concentration between the three groups. Additionally, the median insulin concentration in the hypoglycaemic and normoglycaemic groups was below the detection limit of the assay, suggesting that insulin secretion was appropriately low (i.e. undetectable) in these cases. Only two dogs had inappropriately elevated insulin concentrations. One of these dogs was hypoglycaemic. We conclude that hyperinsulinaemia is an infrequent cause of hypoglycaemia in virulent canine babesiosis. Other causes of hypoglycaemia, such as increased glucose consumption, depletion of hepatic glycogen stores, and hepatic dysfunction with impaired gluconeogenesis, are speculated to play more important roles in the pathophysiology of hypoglycaemia in canine babesiosis.     

间接荧光抗体试验诊断犬吉氏巴贝斯虫病

利用冷藏抗原玻片 ,用间接荧光抗体试验检测感染吉氏巴贝斯虫犬血清 ,具有特异性强、敏感性高、快速、准确、操作简单等特点。对疫区 82份犬血清的检查 ,阳性率为 37 8% ;对非疫区 50份犬血清的检查 ,假阳性率为 2 %。与血液涂片染色检查比较 ,该法检出率高 ,结果可靠 ,可用于犬吉氏巴贝斯虫病的诊断和流行病学调查     

Molecular fluorescent approach to assessing intraerythrocytic hemoprotozoan Babesia canis infection in dogs

The development of recent flow cytometry-based protocols for the diagnosis of canine babesiosis, Babesia gibsoni in particular, has encouraged us to investigate its applicability to detect B. canis-infected erythrocytes as well as optimize the hydroethidine-flow cytometry methodology (HE-FC), using peripheral blood samples from naturally and experimentally infected dogs. Our data demonstrated that HE at 25 microg/ml provided the most outstanding fluorescence profile, able to discriminate between infected and uninfected dogs with no alterations in cell properties such as forward scatter and unspecific fluorescence. The results were expressed as the percentage of positive fluorescent erythrocytes (PPFE) for each individual sample, with 1.53% of PPFE as the cut-off determined between infected and uninfected animals. B. canis-infected erythrocytes during both acute and chronic experimental infection were identified through HE-FC, validating its use for diagnosis purposes in endemic areas for canine babesiosis. In a clinical trial, 22.8% out of 162 dogs showed to be positive to Babesia infection through this approach. Such prevalence was similar to that estimated for altered hematological profiles (HT) < or = 30% (29%), but highly distinct from the prevalence provided by direct blood smear (BS) examination (1.8%) or immunofluorescent assay (IFA) (60.5%). Furthermore, our findings indicate that positive PPFE data was associated with HT < or = 30%, emphasizing that, in clinical practice, the haematocrit should be used as a screening test followed by HE-FC, suitable to confirm hypotheses of canine babesiosis.     

Incidence of canine Babesia gibsoni infection and subclinical infection among Tosa dogs in Aomori Prefecture, Japan

To identify the incidence of Babesia gibsoni (B. gibsoni) in Aomori Prefecture, northeastern Japan, dogs with acute B. gibsoni infection were investigated at the Animal Teaching Hospital, Kitasato University, between April 2002 and March 2003. Eighteen dogs with acute B. gibsoni infection were recognized; they were all male dogs of the fighting dog breed Tosa. Their platelet counts were below normal and their packed cell volumes (PCVs) were at various levels. We collected blood samples from 141 Tosa dogs from Aomori Prefecture and used polymerase chain reaction assay to investigate the incidence of subclinical B. gibsoni infection. We also looked into the serological abnormalities associated with thrombocytopenia or anemia in subclinical infection. Forty-one of 87 dogs (47.1%) with histories of dog fighting, and one dog of 54 without a history of dog fighting were positive for B. gibsoni; that is, 42 of 141 dogs (29.8%) showed a positive result. The mean platelet counts of dogs with subclinical infection were significantly lower and levels of anti-platelet IgG were significantly higher than levels for dogs without infection. Anti-erythrocyte membrane IgG levels were significantly higher in dogs with subclinical infections, although mean PCVs were not significantly different. Tosa dogs from Aomori Prefecture, Japan, were highly infected with B. gibsoni subclinically and this pathogen might be successfully transmitted during dog fighting. Dogs with subclinical infections were at risk of chronic thrombocytopenia, which may be due to autoimmune mechanisms.     

Immunity against Babesia rossi infection in dogs vaccinated with antigens from culture supernatants

Soluble parasite antigens (SPA) from different Babesia species have been shown earlier to induce protective immunity when used as vaccine. However, initial attempts to produce such vaccine against Babesia rossi infection using SPA from B. rossi culture supernatants were not or only partially successful. Here we show that when dogs were vaccinated with a vaccine comprising SPA from B. rossi combined with SPA from Babesia canis protective immunity against experimental challenge infection was induced. Immunity was reflected in reduced clinical signs that resolved spontaneously, and reduction of parasitaemia and SPA in the blood. Not a single infected erythrocyte could be found in blood smears of dogs that had been repeatedly boosted (three vaccinations in total). In contrast, three out of four control dogs required chemotherapeutic treatment to prevent death. The fourth control dog showed a transient parasitaemia that resolved spontaneously. Vaccination did not prevent the development of a transient anaemia. It is concluded that a vaccine containing a mixture of SPA obtained from in vitro culture supernatants of B. rossi and B. canis induces protection in dogs against heterologous challenge infection with B. canis (as shown before) or B. rossi.     

Clinical and pathological findings in a goat with cerebral gliomatosis

This report describes a buck with cerebral gliomatosis. The animal was severely apathetic to somnolent. Neurological examination revealed generalised ataxia and hyper-metria of the fore limbs. There was bilateral mydriasis and severely decreased menace and pupillary light reflexes. Sensitivity to pricking with a needle was markedly reduced over the entire body. There was a delayed response to adduction, abduction and crossing of the limbs and rocking of the animal. Examination of cerebrospinal fluid indicated mild mixed-cell inflammation. Based on all of the findings, an abscess or tumour of the central nervous system with localisation in the cerebrum was suspected. Because of the grave prognosis, the goat was euthanased and a post mortem examination performed. No macroscopic abnormalities were seen in any of the organs including the brain. Histologically, there was extensive diffuse glial cell hyperplasia in the white matter of the cerebral hemispheres and in the brain stem.