Ehrlichia canis, the etiologic agent of canine ehrlichiosis, was isolated in Israel from a natura... more Ehrlichia canis, the etiologic agent of canine ehrlichiosis, was isolated in Israel from a naturally infected dog with acute signs of the disease. The organism designated E. canis 611, was passaged experimentally to a beagle, from which it was propagated in primary canine monocytes. The organism was then grown in vitro in a continuous canine cell line, DH82. Nine beagles subsequently injected with whole E. canis-infected blood all developed typical symptoms of ehrlichiosis. An indirect immunofluorescence antibody test to E. canis was developed and compared with a commercial kit, revealing a good correlation between the two assays. Transmission electron microscopy of DH82 cells infected with the Israeli strain of E. canis (611), revealed organisms similar to those described in the literature: two different forms of morulae appeared, one tightly, the other loosely, packed. The 16S rRNA gene sequence obtained from the Israeli Ehrlichia isolate was compared with other isolates, E. canis Oklahoma and E. canis Florida. The Israeli strain 16S rRNA had three nucleotide differences from the Oklahoma isolate, and four nucleotide differences from the Florida isolate, in addition to one nucleotide gap in each. The Israeli isolate was found to be 0.54% different from the Oklahoma strain, and 0.61% different from the Florida strain. There are the same magnitudes of differences displayed by the other most closely related group in the phylogenetic tree, namely Ehrlichia equi, Ehrlichia phagocytophilia and the human granulocytic ehrlichia.
In order to determine the role of the spleen in the pathogenesis of canine monocytic ehrlichiosis... more 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.
This report presents evidence that dogs recover from acute canine monocytic ehrlichiosis (CME) af... more This report presents evidence that dogs recover from acute canine monocytic ehrlichiosis (CME) after 16 days of doxycycline treatment (10 mg/kg of body weight every 24 h). Blood PCR was as valuable as splenic aspirate PCR for early diagnosis of acute CME. Splenic aspirate PCR was, however, superior to blood PCR for the evaluation of ehrlichial elimination.
This is the largest case-control study of esophageal spirocercosis (ES) in dogs, overall includin... more This is the largest case-control study of esophageal spirocercosis (ES) in dogs, overall including the geographical distribution of 442 such dogs in Israel. The incidence of ES in Israel increased compared to the 1990s, but remained rather constant during the study period. Spirocercosis has spread geographically in Israel compared to previous findings, despite prophylactic avermectin therapy administered by Israeli veterinarians in endemic areas, raising questions as to the efficacy of the currently employed preventive treatment protocol are insufficient. Nonetheless most dogs with ES did not receive any prophylactic treatment against the nematode. There were no differences in the seasonality and monthly incidence of ES, in contrast with previous findings, suggesting that spirocercosis is further established in Israel, becoming endemic. ES is significantly more common in sporting breed and large-breed dogs, in general, particularly in Retrievers, and is less common in toy-breed dogs. Vomiting and regurgitation were the most common clinical signs. However, the clinical presentation of ES highly varies, depending on disease stage, occurrence of aberrant migration and malignant transformation of the esophageal lesions. Hematology and serum chemistry finding in esophageal spirocercosis are nonspecific. Endoscopy, radiography, coproscopy and necropsy findings are provided.
Fleas are acknowledged vectors and reservoirs of various bacteria that present a wide range of pa... more Fleas are acknowledged vectors and reservoirs of various bacteria that present a wide range of pathogenicity. In the present study, fleas collected from wild rodents from the Negev desert in Southern Israel were tested for Rickettsia-DNA by targeting the 16S rRNA (rrs) gene. Thirty eight Xenopsylla ramesis, 91 Synosternus cleopatrae and 15 Leptosylla algira flea-pools (a total of 568 fleas) were screened. Rickettsia-DNA was detected in 100% of the X. ramesis and in one S. cleopatrae flea-pools. None of L. algira flea pools was found positive. All positive flea-pools were further characterized by sequencing of five additional genetic loci (gltA, ompB, ompA, htrA and fusA). The molecular identification of the positive samples showed all sequences to be closely related to the "Rickettsia felis-like" organisms (99-100% similarities in the six loci). In order to further investigate the association between "R. felis-like" and X. ramesis fleas, ten additional single X. ...
Nearly complete 16S rRNA gene sequences for feline and canine hemoplasma isolates from Europe, Au... more Nearly complete 16S rRNA gene sequences for feline and canine hemoplasma isolates from Europe, Australia, Africa, and Asia showed almost 100% identity to those previously reported for United States isolates. Partial sequences of the RNA subunit of the RNase P gene were also determined, and RNase P-based phylogenetic analysis showed that the hemoplasmas are most closely related to the members of the Mycoplasma pneumoniae group.
Nodular masses and granulomas of the esophagus are among the most frequent lesions caused by Spir... more Nodular masses and granulomas of the esophagus are among the most frequent lesions caused by Spirocerca lupi, a nematode parasite of dogs, and neoplastic transformation of these granulomas to osteosarcoma or fibrosarcoma has been described. In this study, we developed a xenograft murine model of S. lupi-associated sarcoma. Samples of esophageal fibrosarcoma and osteosarcomas were excised from three dogs diagnosed with spirocercosis. These sarcomas were inoculated into three groups of 6-week-old NOD/SCID mice to create three tumor lines of S. lupi-associated sarcomas. Mice in all groups developed tumors after inoculation, and the cell lines could be further propagated as second-generation xenografts. We successfully established xenograft murine models of three different lines of S. lupi-associated sarcoma that offer readily available sources of these tumors for further experiments. This resource will facilitate studies on the malignant transformation of the granulomas, establishment ...
Journal of the American Animal Hospital Association, 1996
The nematode Spirocerca lupi (S. lupi), a parasite of dogs and other carnivores, affects mainly t... more The nematode Spirocerca lupi (S. lupi), a parasite of dogs and other carnivores, affects mainly the esophagus and the aorta leading to gastrointestinal, respiratory, and circulatory signs. Aberrant migration of the worm to unusual anatomical structures, especially the thoracic cavity, resulting in atypical clinical signs is being reported more frequently. Aberrant migration of S. lupi is reviewed, and two such cases (i.e., migration to the heart, causing an aortico-pulmonary "window-like" opening, and to a subcutaneous abscess in the caudal thoracic region) are presented.
Interactions between coinfecting parasites1 may take various forms, either direct or indirect, fa... more Interactions between coinfecting parasites1 may take various forms, either direct or indirect, facilitative or competitive, and may be mediated by either bottom-up or top-down mechanisms. While each form of interaction leads to different evolutionary and ecological outcomes, it is challenging to tease them apart throughout the infection period. To establish the first step towards a mechanistic understanding of the interactions between coinfecting limited-term bacterial parasites and lifelong bacterial parasites, we studied the coinfection ofBartonella sp. (limited-term) and Mycoplasma sp. (lifelong), which commonly co-occur in wild rodents. We infected Bartonella and Mycoplasma-free rodents with each species, and simultaneously with both, and quantified the infection dynamics and host responses. Bartonella benefited from the interaction; its infection load decreased more slowly in coinfected rodents than in rodents infected with Bartonella alone. There were no indications for bottom...
Comparative Immunology, Microbiology and Infectious Diseases
Cardiopulmonary dirofilariosis in dogs and other carnivores is caused by Dirofilaria immitis, whi... more Cardiopulmonary dirofilariosis in dogs and other carnivores is caused by Dirofilaria immitis, while Dirofilaria repens usually causes a subcutaneous infection. The importance of red foxes and golden jackals in the epidemiology of dirofilariosis remains unknown. Thus, the aim of this study was to conduct a cross-sectional molecular survey of Dirofilaria species in stray dogs, red foxes and golden jackals from the endemic region of Vojvodina, Serbia, in order to determine and update data on their prevalence and provide insight into the epidemiological importance of wild canids. A total of 59 blood samples from stray dogs, 94 from red foxes and 32 from golden jackals were collected and screened by real-time PCR targeting a 115-bp fragment of the mitochondrial 12S gene of filarioids and by conventional PCR assay targeting a 484-524-bp fragment of 5.8S-ITS2-28S locus of filarioids. The cross-sectional molecular survey detected the filarioid mitochondrial 12S gene fragment in stray dogs (27.1 %), red foxes (8.5 %) and golden jackals (6.3 %) in the same endemic region of Vojvodina, Serbia. Only D. immitis was detected in stray dogs, while both D. immitis and D. repens were detected in populations of red foxes and golden jackals. These results outline a possible interaction of D. immitis infection between the dog population and the wild canid populations, while D. repens was found to circulate mostly in golden jackals and red foxes populations.
Canine monocytic ehrlichiosis (CME) is a potentially fatal tick-borne disease caused by the ricke... more Canine monocytic ehrlichiosis (CME) is a potentially fatal tick-borne disease caused by the rickettsia Ehrlichia canis (16). The etiologic agent was first recognized in Algeria in 1935 (8). Since then, it has been reported worldwide, causing extensive morbidity and mortality among domestic dogs and other canids (11, 28, 51). The principal vector of CME is Rhipicephalus sanguineus (11). Recently, it has been shown experimentally that Dermacentor variabilis is also capable of transmitting E. canis (24). The pathogenesis of CME consists of an incubation period of 8 to 20 days, followed sequentially by acute, subclinical, and in some cases chronic phases. The disease may be manifested by a wide variety of clinical signs of which depression, lethargy, weight loss, anorexia, pyrexia, lymphadenomegaly, splenomegaly, and bleeding tendencies are the most common. Principal hematologic abnormalities include thrombocytopenia, mild anemia and mild leukopenia during the acute stage, mild thrombocytopenia in the subclinical stage, and pancytopenia in the severe chronic stage. The main biochemical abnormalities include hypoalbuminemia, hyperglobulinemia, and hypergammaglobulinemia (16). CME has been researched extensively in the last decade, and special efforts have been made to elucidate the pathogenesis of the disease. Better understanding of major mechanisms involved in the pathogenesis of the disease may assist clinicians in understanding the disease process and providing appropriate treatment, affording a better prognosis to their patients. In the light of the recent emergence of similar ehrlichial pathogens that infect human patients, the understanding of pathogenic processes in CME may contribute to the understanding of human monocytic ehrlichiosis and human granulocytic ehrlichiosis. This article reviews recent investigations in the pathogenesis of CME with special reference to platelet disorders and serum protein alterations, the principal hematological and biochemical abnormalities in CME, respectively. Host immune response in both acute and persistent E. canis infection is discussed and is proposed to be involved in the pathogenesis of disease manifestations.
Sixteen fatal dog envenomations by the snake Vipera palaestinae over a 14-y period are described.... more Sixteen fatal dog envenomations by the snake Vipera palaestinae over a 14-y period are described. Most envenomations occurred during the late night hours in the warm months, and 8/16 dogs were bitten on the limbs. The most frequent clinical signs upon admission were soft tissue swelling and edema, local pain, depression, bleeding, lameness, dyspnea, and 6 dogs were in shock. Thrombocytopenia was present in 14/16 cases and increased hematocrit (13/16) and hemoglobin (9/16) concentration were the most common hematological abnormalities upon admission. Biochemical abnormalities included increased activities of muscle enzymes and alkaline phosphatase, hypocalcemia, and hypocholesterolemia. Creatine kinase activity was markedly increased in 2 dogs. During hospitalization serious complications in many dogs were disseminated intravascular coagulation, acute renal failure, seizures, cardiac arrhythmias, acute necrotizing pancreatitis and severe laryngeal edema; these required intensive and ...
This study aimed to screen wild rodents from southern Chile, for the presence of Anaplasmatacea. ... more This study aimed to screen wild rodents from southern Chile, for the presence of Anaplasmatacea. Spleen samples from 33 wild rodents trapped in Valdivia Province were screened by conventional PCR (cPCR), targeting the Anaplasmataceae 16S rRNA gene (16S). Positive samples were further evaluated, targeting a larger 16S fragment, groEL operon, and gltA gene, followed by sequencing and phylogenetic analysis. Anaplasmataceae DNA was detected in 15% (five of 33) of the tested rodents (Abrothrix sp. [four of five] and Mus musculus [one of five]). Analysis of sequenced products based on the 16S gene revealed high similarity with "Ca. Neoehrlichia mikurensis," "Ca. Neoehrlichia lotoris" and "Ca. Neoehrlichia arcana" (97.8%-98.6%). A lower similarity was observed with Candidatus Neoehrlichia groEL (89.7%-92%) and gltA (79.5%-79.9%) loci. According to the 16SrRNA, groEL and gltA phylogenetic analyses, two closely related genotypes of "Candidatus Neoehrlichia&...
Cutaneous neosporosis manifested by pyogranulomatous ulcerative dermatitis was diagnosed in an 11... more Cutaneous neosporosis manifested by pyogranulomatous ulcerative dermatitis was diagnosed in an 11-year-old male Boxer. Histology revealed numerous intralesional protozoal tachysoites within macrophages and neutrophils. Occasionally, tachysoites were observed within endothelial and epithelial cells. Infection with Neospora caninum was confirmed by avidin biotin complex immunohistochemistry using a Neospora-specific monoclonal antibody. Cutaneous neosporosis is rare and has only been previously described in three cases. This report represents the first case of canine neosporosis in Israel and the Middle East.
Beagle dogs were examined during the subclinical phase of canine ehrlichiosis under controlled co... more Beagle dogs were examined during the subclinical phase of canine ehrlichiosis under controlled conditions. Emphasis was placed on gathering data before artificial inoculation with Ehrlichia canis, and comparing these data with those of the subclinical phase of the disease. In this study all dogs were clinically healthy throughout the 6 month examination period. All subclinically infected dogs had IFA antibody titers to E. canis at a dilution varying from 1:2560 to 1:20480. The most prominent haematological finding was mild thrombocytopenia with a concomitant increase in platelet size, seen in eight of the nine dogs examined. Leukocyte counts were statistically significantly reduced in 78% of the dogs, compared with their preinfection values, with 71% of dogs having significantly reduced absolute neutrophil counts. None of the dogs were either leukopenic nor neutropenic. Six of the nine dogs had increased serum gamma-globulin concentrations. No dogs were overtly anemic, although declines in packed cell volume, haemoglobin concentration and total erythrocyte count were detected in an inconsistent manner among the dogs. It was concluded that, the most reliable parameters for judging possible subclinical ehrlichial infection in beagle dogs was mild thrombocytopenia, together with a persistently high antibody titer to E. canis. Hypergammaglobulinemia would increase the suspicion further. Based on the results presented, routine testing of dogs in E. canis endemic areas is recommended in order to identify and treat dogs in the subclinical phase of the disease.
Six dogs were infected with Ehrlichia canis by intravenous injection of heavily infected DH82 cel... more Six dogs were infected with Ehrlichia canis by intravenous injection of heavily infected DH82 cells. All dogs developed typical signs of canine monocytic ehrlichiosis. Using¯ow cytometric technology, platelet-bound IgG (PBIgG) were detected in 5 of the 6 dogs after experimental infection with E. canis over a period of 3±10 days post infection (PI). The ®rst detection of PBIgG was made as early as day 3 PI in 2 out of 6 dogs, and on day 5 PI in 1 dog. On day 7 PI, PBIgG was detected in 2 dogs, and on day 10 PI in 3 out of 6 dogs. This is the ®rst report documenting the presence of PBIgG following E. canis infection in dogs. This ®nding further supports the theory that the thrombocytopenia seen in canine monocytic ehrlichiosis has an immunological component and that exposure to an infectious agent, in this case the rickettsia E. canis, can trigger autoimmune mechanisms. Due to the heterogenous appearance of PBIgG among the infected dogs it was concluded that other non-immunological mechanisms are probably also involved in the pathogenesis of the thrombocytopenia seen in canine monocytic ehrlichiosis.
Ehrlichia canis, the etiologic agent of canine ehrlichiosis, was isolated in Israel from a natura... more Ehrlichia canis, the etiologic agent of canine ehrlichiosis, was isolated in Israel from a naturally infected dog with acute signs of the disease. The organism designated E. canis 611, was passaged experimentally to a beagle, from which it was propagated in primary canine monocytes. The organism was then grown in vitro in a continuous canine cell line, DH82. Nine beagles subsequently injected with whole E. canis-infected blood all developed typical symptoms of ehrlichiosis. An indirect immunofluorescence antibody test to E. canis was developed and compared with a commercial kit, revealing a good correlation between the two assays. Transmission electron microscopy of DH82 cells infected with the Israeli strain of E. canis (611), revealed organisms similar to those described in the literature: two different forms of morulae appeared, one tightly, the other loosely, packed. The 16S rRNA gene sequence obtained from the Israeli Ehrlichia isolate was compared with other isolates, E. canis Oklahoma and E. canis Florida. The Israeli strain 16S rRNA had three nucleotide differences from the Oklahoma isolate, and four nucleotide differences from the Florida isolate, in addition to one nucleotide gap in each. The Israeli isolate was found to be 0.54% different from the Oklahoma strain, and 0.61% different from the Florida strain. There are the same magnitudes of differences displayed by the other most closely related group in the phylogenetic tree, namely Ehrlichia equi, Ehrlichia phagocytophilia and the human granulocytic ehrlichia.
In order to determine the role of the spleen in the pathogenesis of canine monocytic ehrlichiosis... more 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.
This report presents evidence that dogs recover from acute canine monocytic ehrlichiosis (CME) af... more This report presents evidence that dogs recover from acute canine monocytic ehrlichiosis (CME) after 16 days of doxycycline treatment (10 mg/kg of body weight every 24 h). Blood PCR was as valuable as splenic aspirate PCR for early diagnosis of acute CME. Splenic aspirate PCR was, however, superior to blood PCR for the evaluation of ehrlichial elimination.
This is the largest case-control study of esophageal spirocercosis (ES) in dogs, overall includin... more This is the largest case-control study of esophageal spirocercosis (ES) in dogs, overall including the geographical distribution of 442 such dogs in Israel. The incidence of ES in Israel increased compared to the 1990s, but remained rather constant during the study period. Spirocercosis has spread geographically in Israel compared to previous findings, despite prophylactic avermectin therapy administered by Israeli veterinarians in endemic areas, raising questions as to the efficacy of the currently employed preventive treatment protocol are insufficient. Nonetheless most dogs with ES did not receive any prophylactic treatment against the nematode. There were no differences in the seasonality and monthly incidence of ES, in contrast with previous findings, suggesting that spirocercosis is further established in Israel, becoming endemic. ES is significantly more common in sporting breed and large-breed dogs, in general, particularly in Retrievers, and is less common in toy-breed dogs. Vomiting and regurgitation were the most common clinical signs. However, the clinical presentation of ES highly varies, depending on disease stage, occurrence of aberrant migration and malignant transformation of the esophageal lesions. Hematology and serum chemistry finding in esophageal spirocercosis are nonspecific. Endoscopy, radiography, coproscopy and necropsy findings are provided.
Fleas are acknowledged vectors and reservoirs of various bacteria that present a wide range of pa... more Fleas are acknowledged vectors and reservoirs of various bacteria that present a wide range of pathogenicity. In the present study, fleas collected from wild rodents from the Negev desert in Southern Israel were tested for Rickettsia-DNA by targeting the 16S rRNA (rrs) gene. Thirty eight Xenopsylla ramesis, 91 Synosternus cleopatrae and 15 Leptosylla algira flea-pools (a total of 568 fleas) were screened. Rickettsia-DNA was detected in 100% of the X. ramesis and in one S. cleopatrae flea-pools. None of L. algira flea pools was found positive. All positive flea-pools were further characterized by sequencing of five additional genetic loci (gltA, ompB, ompA, htrA and fusA). The molecular identification of the positive samples showed all sequences to be closely related to the "Rickettsia felis-like" organisms (99-100% similarities in the six loci). In order to further investigate the association between "R. felis-like" and X. ramesis fleas, ten additional single X. ...
Nearly complete 16S rRNA gene sequences for feline and canine hemoplasma isolates from Europe, Au... more Nearly complete 16S rRNA gene sequences for feline and canine hemoplasma isolates from Europe, Australia, Africa, and Asia showed almost 100% identity to those previously reported for United States isolates. Partial sequences of the RNA subunit of the RNase P gene were also determined, and RNase P-based phylogenetic analysis showed that the hemoplasmas are most closely related to the members of the Mycoplasma pneumoniae group.
Nodular masses and granulomas of the esophagus are among the most frequent lesions caused by Spir... more Nodular masses and granulomas of the esophagus are among the most frequent lesions caused by Spirocerca lupi, a nematode parasite of dogs, and neoplastic transformation of these granulomas to osteosarcoma or fibrosarcoma has been described. In this study, we developed a xenograft murine model of S. lupi-associated sarcoma. Samples of esophageal fibrosarcoma and osteosarcomas were excised from three dogs diagnosed with spirocercosis. These sarcomas were inoculated into three groups of 6-week-old NOD/SCID mice to create three tumor lines of S. lupi-associated sarcomas. Mice in all groups developed tumors after inoculation, and the cell lines could be further propagated as second-generation xenografts. We successfully established xenograft murine models of three different lines of S. lupi-associated sarcoma that offer readily available sources of these tumors for further experiments. This resource will facilitate studies on the malignant transformation of the granulomas, establishment ...
Journal of the American Animal Hospital Association, 1996
The nematode Spirocerca lupi (S. lupi), a parasite of dogs and other carnivores, affects mainly t... more The nematode Spirocerca lupi (S. lupi), a parasite of dogs and other carnivores, affects mainly the esophagus and the aorta leading to gastrointestinal, respiratory, and circulatory signs. Aberrant migration of the worm to unusual anatomical structures, especially the thoracic cavity, resulting in atypical clinical signs is being reported more frequently. Aberrant migration of S. lupi is reviewed, and two such cases (i.e., migration to the heart, causing an aortico-pulmonary "window-like" opening, and to a subcutaneous abscess in the caudal thoracic region) are presented.
Interactions between coinfecting parasites1 may take various forms, either direct or indirect, fa... more Interactions between coinfecting parasites1 may take various forms, either direct or indirect, facilitative or competitive, and may be mediated by either bottom-up or top-down mechanisms. While each form of interaction leads to different evolutionary and ecological outcomes, it is challenging to tease them apart throughout the infection period. To establish the first step towards a mechanistic understanding of the interactions between coinfecting limited-term bacterial parasites and lifelong bacterial parasites, we studied the coinfection ofBartonella sp. (limited-term) and Mycoplasma sp. (lifelong), which commonly co-occur in wild rodents. We infected Bartonella and Mycoplasma-free rodents with each species, and simultaneously with both, and quantified the infection dynamics and host responses. Bartonella benefited from the interaction; its infection load decreased more slowly in coinfected rodents than in rodents infected with Bartonella alone. There were no indications for bottom...
Comparative Immunology, Microbiology and Infectious Diseases
Cardiopulmonary dirofilariosis in dogs and other carnivores is caused by Dirofilaria immitis, whi... more Cardiopulmonary dirofilariosis in dogs and other carnivores is caused by Dirofilaria immitis, while Dirofilaria repens usually causes a subcutaneous infection. The importance of red foxes and golden jackals in the epidemiology of dirofilariosis remains unknown. Thus, the aim of this study was to conduct a cross-sectional molecular survey of Dirofilaria species in stray dogs, red foxes and golden jackals from the endemic region of Vojvodina, Serbia, in order to determine and update data on their prevalence and provide insight into the epidemiological importance of wild canids. A total of 59 blood samples from stray dogs, 94 from red foxes and 32 from golden jackals were collected and screened by real-time PCR targeting a 115-bp fragment of the mitochondrial 12S gene of filarioids and by conventional PCR assay targeting a 484-524-bp fragment of 5.8S-ITS2-28S locus of filarioids. The cross-sectional molecular survey detected the filarioid mitochondrial 12S gene fragment in stray dogs (27.1 %), red foxes (8.5 %) and golden jackals (6.3 %) in the same endemic region of Vojvodina, Serbia. Only D. immitis was detected in stray dogs, while both D. immitis and D. repens were detected in populations of red foxes and golden jackals. These results outline a possible interaction of D. immitis infection between the dog population and the wild canid populations, while D. repens was found to circulate mostly in golden jackals and red foxes populations.
Canine monocytic ehrlichiosis (CME) is a potentially fatal tick-borne disease caused by the ricke... more Canine monocytic ehrlichiosis (CME) is a potentially fatal tick-borne disease caused by the rickettsia Ehrlichia canis (16). The etiologic agent was first recognized in Algeria in 1935 (8). Since then, it has been reported worldwide, causing extensive morbidity and mortality among domestic dogs and other canids (11, 28, 51). The principal vector of CME is Rhipicephalus sanguineus (11). Recently, it has been shown experimentally that Dermacentor variabilis is also capable of transmitting E. canis (24). The pathogenesis of CME consists of an incubation period of 8 to 20 days, followed sequentially by acute, subclinical, and in some cases chronic phases. The disease may be manifested by a wide variety of clinical signs of which depression, lethargy, weight loss, anorexia, pyrexia, lymphadenomegaly, splenomegaly, and bleeding tendencies are the most common. Principal hematologic abnormalities include thrombocytopenia, mild anemia and mild leukopenia during the acute stage, mild thrombocytopenia in the subclinical stage, and pancytopenia in the severe chronic stage. The main biochemical abnormalities include hypoalbuminemia, hyperglobulinemia, and hypergammaglobulinemia (16). CME has been researched extensively in the last decade, and special efforts have been made to elucidate the pathogenesis of the disease. Better understanding of major mechanisms involved in the pathogenesis of the disease may assist clinicians in understanding the disease process and providing appropriate treatment, affording a better prognosis to their patients. In the light of the recent emergence of similar ehrlichial pathogens that infect human patients, the understanding of pathogenic processes in CME may contribute to the understanding of human monocytic ehrlichiosis and human granulocytic ehrlichiosis. This article reviews recent investigations in the pathogenesis of CME with special reference to platelet disorders and serum protein alterations, the principal hematological and biochemical abnormalities in CME, respectively. Host immune response in both acute and persistent E. canis infection is discussed and is proposed to be involved in the pathogenesis of disease manifestations.
Sixteen fatal dog envenomations by the snake Vipera palaestinae over a 14-y period are described.... more Sixteen fatal dog envenomations by the snake Vipera palaestinae over a 14-y period are described. Most envenomations occurred during the late night hours in the warm months, and 8/16 dogs were bitten on the limbs. The most frequent clinical signs upon admission were soft tissue swelling and edema, local pain, depression, bleeding, lameness, dyspnea, and 6 dogs were in shock. Thrombocytopenia was present in 14/16 cases and increased hematocrit (13/16) and hemoglobin (9/16) concentration were the most common hematological abnormalities upon admission. Biochemical abnormalities included increased activities of muscle enzymes and alkaline phosphatase, hypocalcemia, and hypocholesterolemia. Creatine kinase activity was markedly increased in 2 dogs. During hospitalization serious complications in many dogs were disseminated intravascular coagulation, acute renal failure, seizures, cardiac arrhythmias, acute necrotizing pancreatitis and severe laryngeal edema; these required intensive and ...
This study aimed to screen wild rodents from southern Chile, for the presence of Anaplasmatacea. ... more This study aimed to screen wild rodents from southern Chile, for the presence of Anaplasmatacea. Spleen samples from 33 wild rodents trapped in Valdivia Province were screened by conventional PCR (cPCR), targeting the Anaplasmataceae 16S rRNA gene (16S). Positive samples were further evaluated, targeting a larger 16S fragment, groEL operon, and gltA gene, followed by sequencing and phylogenetic analysis. Anaplasmataceae DNA was detected in 15% (five of 33) of the tested rodents (Abrothrix sp. [four of five] and Mus musculus [one of five]). Analysis of sequenced products based on the 16S gene revealed high similarity with "Ca. Neoehrlichia mikurensis," "Ca. Neoehrlichia lotoris" and "Ca. Neoehrlichia arcana" (97.8%-98.6%). A lower similarity was observed with Candidatus Neoehrlichia groEL (89.7%-92%) and gltA (79.5%-79.9%) loci. According to the 16SrRNA, groEL and gltA phylogenetic analyses, two closely related genotypes of "Candidatus Neoehrlichia&...
Cutaneous neosporosis manifested by pyogranulomatous ulcerative dermatitis was diagnosed in an 11... more Cutaneous neosporosis manifested by pyogranulomatous ulcerative dermatitis was diagnosed in an 11-year-old male Boxer. Histology revealed numerous intralesional protozoal tachysoites within macrophages and neutrophils. Occasionally, tachysoites were observed within endothelial and epithelial cells. Infection with Neospora caninum was confirmed by avidin biotin complex immunohistochemistry using a Neospora-specific monoclonal antibody. Cutaneous neosporosis is rare and has only been previously described in three cases. This report represents the first case of canine neosporosis in Israel and the Middle East.
Beagle dogs were examined during the subclinical phase of canine ehrlichiosis under controlled co... more Beagle dogs were examined during the subclinical phase of canine ehrlichiosis under controlled conditions. Emphasis was placed on gathering data before artificial inoculation with Ehrlichia canis, and comparing these data with those of the subclinical phase of the disease. In this study all dogs were clinically healthy throughout the 6 month examination period. All subclinically infected dogs had IFA antibody titers to E. canis at a dilution varying from 1:2560 to 1:20480. The most prominent haematological finding was mild thrombocytopenia with a concomitant increase in platelet size, seen in eight of the nine dogs examined. Leukocyte counts were statistically significantly reduced in 78% of the dogs, compared with their preinfection values, with 71% of dogs having significantly reduced absolute neutrophil counts. None of the dogs were either leukopenic nor neutropenic. Six of the nine dogs had increased serum gamma-globulin concentrations. No dogs were overtly anemic, although declines in packed cell volume, haemoglobin concentration and total erythrocyte count were detected in an inconsistent manner among the dogs. It was concluded that, the most reliable parameters for judging possible subclinical ehrlichial infection in beagle dogs was mild thrombocytopenia, together with a persistently high antibody titer to E. canis. Hypergammaglobulinemia would increase the suspicion further. Based on the results presented, routine testing of dogs in E. canis endemic areas is recommended in order to identify and treat dogs in the subclinical phase of the disease.
Six dogs were infected with Ehrlichia canis by intravenous injection of heavily infected DH82 cel... more Six dogs were infected with Ehrlichia canis by intravenous injection of heavily infected DH82 cells. All dogs developed typical signs of canine monocytic ehrlichiosis. Using¯ow cytometric technology, platelet-bound IgG (PBIgG) were detected in 5 of the 6 dogs after experimental infection with E. canis over a period of 3±10 days post infection (PI). The ®rst detection of PBIgG was made as early as day 3 PI in 2 out of 6 dogs, and on day 5 PI in 1 dog. On day 7 PI, PBIgG was detected in 2 dogs, and on day 10 PI in 3 out of 6 dogs. This is the ®rst report documenting the presence of PBIgG following E. canis infection in dogs. This ®nding further supports the theory that the thrombocytopenia seen in canine monocytic ehrlichiosis has an immunological component and that exposure to an infectious agent, in this case the rickettsia E. canis, can trigger autoimmune mechanisms. Due to the heterogenous appearance of PBIgG among the infected dogs it was concluded that other non-immunological mechanisms are probably also involved in the pathogenesis of the thrombocytopenia seen in canine monocytic ehrlichiosis.
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Papers by S. Harrus