Immunoreactive Protein Repertoires of Ehrlichia chaffeensis and E. canis Reveal the Dominance of Hypothetical Proteins and Conformation-Dependent Antibody Epitopes.

The immunomes of Ehrlichia chaffeensis and Ehrlichia canis have recently been revised to include immunodominant hypothetical proteins with conformational antibody epitopes. In this study, we examined 216 E. chaffeensis and 190 E. canis highly antigenic proteins according to ANTIGENpro and also performed a genome-wide hypothetical protein analysis (E. chaffeensis n = 104; E. canis n = 124) for immunoreactivity. Using cell-free protein expression and immunoanalysis, 118 E. chaffeensis and 39 E. canis proteins reacted with sera from naturally E. chaffeensis-infected patients or E. canis-infected dogs. Moreover, 22 E. chaffeensis and 18 E. canis proteins consistently and strongly reacted with a panel of patient or canine sera. A subset of E. chaffeensis (n = 18) and E. canis (n = 9) proteins were identified as immunodominant. Consistent with our previous study, most proteins were classified as hypothetical, and the antibody epitopes exhibited complete or partial conformation dependence. The majority (28/40, 70%) of E. chaffeensis and E. canis proteins contained transmembrane domains, and 19 (48%) were predicted to be secreted effectors. The antigenic repertoires of E. chaffeensis and E. canis were mostly diverse and suggest that the immunomes of these closely related ehrlichiae are dominated by species-specific conformational antibody epitopes. This study reveals a significant group of previously undefined E. chaffeensis and E. canis antigens and reaffirms the importance of conformation-dependent epitopes as targets of anti-Ehrlichia immune responses. These findings substantially expand our understanding of host-Ehrlichia immune responses, advance efforts to define the molecular features of protective proteins, and improve prospects for effective vaccines for the ehrlichioses.

Seroprevalence and Genotypic Analysis of Ehrlichia canis Infection in Dogs and Humans in Cauca, Colombia.

Ehrlichia canis infections have been reported in humans in Venezuela and Costa Rica. In this study, 506 healthy residents and 114 dogs from four municipalities (Cauca, Colombia) were surveyed and blood samples collected. Antibodies to E. canis in human and canine sera were evaluated using the Tandem repeat protein 19 (TRP19) peptide ELISA and indirect immunofluorescence assay (IFA). Ehrlichia canis TRP19 antibodies were detected in only 1/506 human sera, but the single positive sample was negative by IFA. The majority (75/114; 66%) of dogs surveyed had antibodies to the E. canis TRP19 peptide by ELISA, and eight randomly selected sera were further confirmed by E. canis IFA. Genomic DNA samples obtained from 73 E. canis TRP19 ELISA-positive dog blood samples were examined by PCR targeting the 16S ribosomal ribonucleic acid (rRNA) gene. Ehrlichia canis 16S rRNA was amplified in 30 (41%) of the dogs, and 16 amplicons were selected for DNA sequencing, which confirmed that all were E. canis. A second PCR was performed on the 16 confirmed E. canis 16S rRNA PCR-positive samples to determine the TRP36 genotype by amplifying the trp36 gene. TRP36 PCR amplicon sequencing identified nine dogs infected with the U.S. E. canis TRP36 genotype (56%), one dog with the Brazilian genotype (6%), and six dogs with the Costa Rican genotype (38%). Moreover, these molecular genotype signatures were consistent with serologic analysis using TRP36 genotype-specific peptides. Notably, there was no serologic evidence of E. canis infection in humans, suggesting that E. canis infection in dogs in Cauca is not associated with zoonotic human infection.

Frequency of co-seropositivities for certain pathogens and their relationship with clinical and histopathological changes and parasite load in dogs infected with Leishmania infantum.

In canine leishmaniosis caused by the protozoan Leishmania infantum, little is known about how co-infections with or co-seropositivities for other pathogens can influence aggravation of this disease. Therefore, the objectives of this study were to evaluate the frequency of co-infections with or co-seropositivities for certain pathogens in dogs seropositive for L. infantum and their relationship with clinical signs, histological changes and L. infantum load. Sixty-six L. infantum-seropositive dogs were submitted to clinical examination, collection of blood and bone marrow, culling, and necropsy. Antibodies against Anaplasma spp., Borrelia burgdorferi sensu lato, Ehrlichia spp. and Toxoplasma gondii and Dirofilaria immitis antigens were investigated in serum. Samples from different tissues were submitted to histopathology and immunohistochemistry for the detection of Leishmania spp. and T. gondii. Quantitative real-time PCR was used to assess the L. infantum load in spleen samples. For detection of Coxiella burnetii, conventional PCR and nested PCR were performed using bone marrow samples. All 66 dogs tested positive for L. infantum by qPCR and/or culture. Fifty dogs (76%) were co-seropositive for at least one pathogen: T. gondii (59%), Ehrlichia spp., (41%), and Anaplasma spp. (18%). Clinical signs were observed in 15 (94%) dogs monoinfected with L. infantum and in 45 (90%) dogs co-seropositive for certain pathogens. The L. infantum load in spleen and skin did not differ significantly between monoinfected and co-seropositive dogs. The number of inflammatory cells was higher in the spleen, lung and mammary gland of co-seropositive dogs and in the mitral valve of monoinfected dogs. These results suggest that dogs infected with L. infantum and co-seropositive for certain pathogens are common in the region studied. However, co-seropositivities for certain pathogens did not aggravate clinical signs or L. infantum load, although they were associated with a more intense inflammatory reaction in some organs.

Canine infection with Dirofilaria immitis, Borrelia burgdorferi, Anaplasma spp., and Ehrlichia spp. in the United States, 2013-2019.

BACKGROUND: Dogs in the US are commonly infected with vector-borne pathogens, including heartworm and tick-borne disease agents. The geographic distribution of both arthropod vectors and the pathogens they transmit continues to expand. METHODS: To describe the current geographic distribution and prevalence of antigen of Dirofilaria immitis and antibody to Borrelia burgdorferi, Ehrlichia spp., and Anaplasma spp. in dogs, we summarized over 144 million test results from 2013 to 2019, inclusive, by county, state, and region. Canine seroprevalence by state was compared to population-adjusted human reports of tick-borne diseases. RESULTS: Results varied regionally, with D. immitis antigen and Ehrlichia spp. antibodies more frequently detected in the Southeast (2.6% and 5.2%, respectively) and antibody to B. burgdorferi and Anaplasma spp. most common in the Northeast (12.1% and 7.3%, respectively). Overall, percent positive test results to D. immitis decreased in the Southeast by 33.3% when compared to earlier summaries using the same strategy (from 3.9 to 2.6%). Geographic expansion of areas where dogs commonly test positive for Ehrlichia spp. was evident, likely because of a change in the test made in 2012 to allow detection of antibodies to E. ewingii concomitant with expansion of vector tick populations. Percent positive test results to Ehrlichia spp. increased in every region; this shift was particularly pronounced in the Southeast, where percent positive test results increased fourfold (from 1.3 to 5.2%). Continued geographic expansion of B. burgdorferi and A. phagocytophilum was apparent in the Northeast, Midwest, and Upper South, although canine seroprevalence of antibody to B. burgdorferi was much lower than prior surveys in many Lyme-endemic areas. Annual reports of human cases of Lyme disease, ehrlichiosis, and anaplasmosis were associated with percent positive canine results by state for the three tick-borne disease agents (R2 = 0.812, 0.521, and 0.546, respectively). Within endemic areas, percent positive test results for all three tick-borne agents demonstrated evidence of geographic expansion. CONCLUSIONS: Large scale analysis of results from screening dogs in practice for evidence of vector-borne infections, including those with zoonotic importance, continues to be a valuable strategy for understanding geographic trends in infection risk over time.

Changes in renal parameters and their association with subclinical vector-borne infections in Bernese Mountain dogs.

BACKGROUND: An increased risk for glomerulonephritis and a higher prevalence of antibodies to Borrelia (B.) burgdorferi sensu lato have been reported in Bernese mountain dogs (BMDs). The aim of the study was to determine the prevalence of laboratory abnormalities suggestive of kidney disease in clinically healthy BMDs compared to a control population and to investigate if there is a correlation with the occurrence of antibodies to B. burgdorferi sensu lato, Ehrlichia canis, and Anaplasma (A.) spp. and with the occurrence of Dirofilaria (D.) immitis antigen. A total of 197 BMDs and 57 control dogs were included in the study. Laboratory evidence of kidney disease was defined as renal azotemia and/or proteinuria with a urine protein creatinine ration of more than 0.5 in an inactive urine sediment. A SNAP®4Dx® ELISA (IDEXX, Laboratories, Inc., Westbrook, ME, USA) was used to detect antibodies to B. burgdorferi sensu lato, E. canis and Anaplasma spp. and antigen of D. immitis. RESULTS: Laboratory evidence of kidney disease was significantly more common in BMDs than in control dogs (17.8% versus 1.8%) (p = 0.005). The proportion of BMDs with anti-B. burgdorferi sensu latu antibodies and anti-A. phagocytophilum antibodies was significantly higher in BMDs (p <  0.001). However, an association between these findings could not be identified. CONCLUSION: BMDs are more often affected by kidney disease and have a higher prevalence of antibodies to bacterial pathogens transmitted by Ixodes ticks than control dogs. However, a causal relationship between these two variables could not be established due to a lack of association between these two findings.

Local and regional temporal trends (2013-2019) of canine Ehrlichia spp. seroprevalence in the USA.

BACKGROUND: In the USA, there are several Ehrlichia spp. of concern including Ehrlichia canis, Ehrlichia ewingii, Ehrlichia chaffeensis, Ehrlichia muris eauclarensis, and "Panola Mountain Ehrlichia". Of these, E. canis is considered the most clinically relevant for domestic dogs, with infection capable of causing acute, subclinical, and chronic stages of disease. Changes in climate, land use, habitats, and wildlife reservoir populations, and increasing contact between both human and dog populations with natural areas have resulted in the increased risk of vector-borne disease throughout the world. METHODS: A Bayesian spatio-temporal binomial regression model was applied to serological test results collected from veterinarians throughout the contiguous USA between January 2013 and November 2019. The model was used to quantify both regional and local temporal trends of canine Ehrlichia spp. seroprevalence and identify areas that experienced significant increases in seroprevalence. RESULTS: Regionally, increasing seroprevalence occurred within several states throughout the central and southeastern states, including Missouri, Arkansas, Mississippi, Alabama, Virginia, North Carolina, Georgia and Texas. The underlying local trends revealed increasing seroprevalence at a finer scale. Clusters of locally increasing seroprevalence were seen from the western Appalachian region into the southern Midwest, along the Atlantic coast in New England, parts of Florida, Illinois, Wisconsin and Minnesota, and in a couple areas of the Mountain region. Clusters of locally decreasing seroprevalence were seen throughout the USA including New York and the mid-Atlantic states, Texas, the Midwest, and California. CONCLUSIONS: Canine Ehrlichia spp. seroprevalence is increasing in both endemic and non-endemic areas of the USA. The findings from this study indicate that dogs across a wide area of the USA are at risk of exposure and these results should provide veterinarians and pet owners with the information they need to make informed decisions about prevention of tick exposure.

Immuno-molecular prospecting for vector-borne diseases in central Mexico.

Climatic changes have influenced the temporal and spatial distribution of diseases. In livestock-grazing areas, rodents are reservoirs of zoonotic pathogens; therefore, they play an important role in the transmission of diseases affecting domestic animals and humans. The objective of this study was to investigate the presence of the zoonotic agents: Anaplasma phagocytophilum, Borrelia burgdorferi, Ehrlichia canis and Rickettsia rickettsii, as well as the presence of viral RNA from the Bunyaviridae, Togaviridae and Flaviviridae families, in wild rodents from animal production units in central Mexico. The samples were obtained from wild rodents that had access and contact with animal production units. A total of 92 rodents were captured, and samples of blood, serum and organs, such as spleen, kidney, heart and liver, were obtained. The serum was used to detect antibodies against Anaplasma phagocytophilum, Borrelia burgdorferi, Ehrlichia canis and Rickettsia rickettsii by an immunofluorescence antibody test (IFAT); the blood was used for PCR analysis; and the organs were used to obtain RNA (cDNA) to perform RT-PCR. By IFAT, all samples were positive to A. phagocytophilum and E. canis, and negative to B. burgdorferi and R. rickettsii. The samples that were positive to IFAT were used to confirm the presence of pathogen by PCR analysis. The results from the PCR were as follows: 34 samples were positive to A. phagocytophilum, and 59 to E. canis. There was no amplification of genetic material from the Bunyaviridae, Flaviviridae and Togaviridae virus families from the organs that were sampled, which suggests that the samples obtained did not contain RNA specific to these families. This is the first immuno-molecular prospecting study on vector-borne diseases in central Mexico demonstrating the presence of A. phagocytophilum and E. canis in wild rodents living in cattle grazing areas.

Seroprevalence and risk factors associated with Ehrlichia canis in a hospital canine population.

BACKGROUND: Ehrlichia canis (E canis) infection has been documented in a few small canine case series in Greece. However, there is limited information on the prevalence of exposure to, or the potential risk factors associated with E canis seroreactivity in a large native canine population. OBJECTIVES: The objectives of this study were to evaluate E canis seroprevalence in dogs admitted to a veterinary teaching hospital, and to investigate the potential association between seropositivity and signalment, health status, the serologic assays used, and selected clinical and clinicopathologic abnormalities. METHODS: The medical records of 850 client-owned dogs, tested using three in-office serologic assays, were retrospectively reviewed. RESULTS: The E canis seroprevalence was significantly higher in sick (54.9%) compared with healthy (33.9%) dogs. Seropositivity differed significantly between the serologic assays used in this study (ImmunoComb vs SNAP 3Dx/SNAP 4Dx). Dogs presenting with bleeding tendencies, anemia, thrombocytopenia, leukopenia, pancytopenia, and hyperproteinemia were more likely to be E canis seropositive, and the median hematocrit (HCT), white blood cell (WBC), neutrophil, and platelet values were significantly lower in seropositive compared with seronegative dogs. CONCLUSIONS: A high E canis seroprevalence was documented in a canine population living in an endemic area. Selected clinicopathologic variables might be useful indicators of E canis exposure and could allow the prioritization of serologic testing in the clinical setting.

Occurrence of Ehrlichia canis and Hepatozoon canis and probable exposure to Rickettsia amblyommatis in dogs and cats in Natal, RN / Ocorrência de Ehrlichia canis, Hepatozoon canis e provável exposição a Rickettsia amblyommatis em cães e gatos de Natal, RN

Abstract Occurrence of infection or exposure to Ehrlichia canis, Hepatozoon canis and Rickettsia spp. was detected in feral cats living in two fragments from Atlantic rainforest, in Natal, RN, Brazil, and in dogs living around the parks. While serum samples were collected from 155 animals (53 cats living in the parks; 29 dogs living in human homes around the parks; and 73 dogs living at an animal control center - ACC), spleen samples were collected from 20 dogs that were euthanized at ACC. Serum samples were analyzed to Rickettsia spp. and E. canis antibodies using the indirect immunofluorescence assay. Seventeen of the 102 dogs (17%) had E. canis antibodies and 13% (20/155) of all dogs and cats (i.e. 3% (3/102) of the dogs and 32% (17/53) of the cats) were seropositive for Rickettsia spp. antigens. The animals were therefore been exposed to R. amblyommatis or by a very closely related genotype. Among the 20 dog spleen samples analyzed, eight were PCR positive for E. canis and two for H. canis (GenBank accession number MG772657 and MG772658, respectively). In none of the spleen samples were obtained amplicons for Babesia spp. through PCR. This study provided the first evidence that Rickettsia of the spotted fever group is circulating among dogs and cats in Natal.

Resumo A ocorrência de infecção ou exposição para Ehrlichia canis, Hepatozoon canis e Rickettsia spp. foi determinada em gatos ferais que viviam em dois fragmentos da Mata Atlântica, localizados em Natal, RN, Brasil e em cães que viviam em torno dos parques e em outras regiões da cidade. Enquanto amostras de soro foram coletadas de 155 animais (53 gatos que viviam nos parques, 29 cães com domicilio em torno dos parques e 73 cães do Centro de Controle de Animais -CCA), fragmentos de baço foram coletados de 20 cães eutanasiados no CCA. A detecção de anticorpos nas amostras de soros coletadas contra Rickettsia spp. e E. canis foi realizada pela Reação de Imunofluorescência Indireta. Dezessete dos 102 cães (17%) apresentaram anticorpos anti E. canis e 13% (20/155) de todos os cães e gatos (ou seja, 3% (3/102) dos cães e 32% (17/53) dos gatos) foram soropositivos para antígenos de Rickettsia spp. Os animais foram considerados expostos à R. amblyommatis ou a um genótipo muito relacionado. Entre as 20 amostras de baço de cães analisadas, oito foram positivas para E. canis e duas para Hepatozoon canis (números de acesso ao Genbank MG772657 e MG772658, respectivamente). Nenhuma das amostras de baço produziram amplicons de Babesia spp. na PCR. Observou-se, pela primeira vez, a circulação de Rickettsia do grupo da febre maculosa em cães e gatos em Natal, RN.

Clinicopathological findings in 41 dogs (2008-2018) naturally infected with Ehrlichia ewingii.

BACKGROUND: Ehrlichia ewingii is the most seroprevalent Ehrlichia-infecting dogs in the southern and mid-western United States. Fever, lameness, and polyarthritis are commonly reported findings in dogs naturally infected with E. ewingii. OBJECTIVES: To evaluate clinicopathologic findings in a population of dogs naturally infected with E. ewingii. ANIMALS: Forty-one dogs PCR positive for E. ewingii and PCR negative for other targeted vector-borne organisms. METHODS: Retrospective study. Clinical and clinicopathologic data including physical examination findings, CBC, serum biochemistry, urinalysis (UA), symmetric dimethylarginine (SDMA), and vector-borne disease diagnostic results were reviewed. RESULTS: Frequent clinical diagnoses other than ehrlichiosis (28/41; 68.3%) were renal disease (7/41; 17.1%) and immune-mediated hemolytic anemia (IMHA) (6/41; 14.6%). The most frequent physical examination finding was joint pain (14/41; 34.1%). Prominent hematologic and biochemical abnormalities included abnormal lymphocyte counts (22/36; 61.1%); neutrophilia (21/37; 56.8%); increased alkaline phosphatase (20/35; 57.1%) and alanine transaminase (14/35; 40%) activities; and increased SDMA concentration (11/34; 32.4%). Urinalysis abnormalities included proteinuria (20/27; 74%), most with inactive sediments (16/20; 80%). Dogs were seroreactive by Ehrlichia canis immunofluorescence assay (IFA; 17/39; 43.6%) and Ehrlichia ELISA (34/41; 82.9%). Seroreactivity by IFA for other vector-borne pathogens included Bartonella (1/39; 2.6%), Rickettsia rickettsii (spotted-fever group rickettsiae) (12/39; 30.8%), and Borrelia burgdorferi by ELISA (1/41; 2.4%). CONCLUSIONS AND CLINICAL IMPORTANCE: Renal disease, IMHA, proteinuria, neutrophilia, abnormal lymphocytes, and increased liver enzyme activities were common in this group of E. ewingii-infected dogs. Studies are needed to determine if E. ewingii contributes to comorbidities or is a precipitating factor in clinical syndromes in persistently infected dogs.

Occurrence of Ehrlichia canis and Hepatozoon canis and probable exposure to Rickettsia amblyommatis in dogs and cats in Natal, RN.

Occurrence of infection or exposure to Ehrlichia canis, Hepatozoon canis and Rickettsia spp. was detected in feral cats living in two fragments from Atlantic rainforest, in Natal, RN, Brazil, and in dogs living around the parks. While serum samples were collected from 155 animals (53 cats living in the parks; 29 dogs living in human homes around the parks; and 73 dogs living at an animal control center - ACC), spleen samples were collected from 20 dogs that were euthanized at ACC. Serum samples were analyzed to Rickettsia spp. and E. canis antibodies using the indirect immunofluorescence assay. Seventeen of the 102 dogs (17%) had E. canis antibodies and 13% (20/155) of all dogs and cats (i.e. 3% (3/102) of the dogs and 32% (17/53) of the cats) were seropositive for Rickettsia spp. antigens. The animals were therefore been exposed to R. amblyommatis or by a very closely related genotype. Among the 20 dog spleen samples analyzed, eight were PCR positive for E. canis and two for H. canis (GenBank accession number MG772657 and MG772658, respectively). In none of the spleen samples were obtained amplicons for Babesia spp. through PCR. This study provided the first evidence that Rickettsia of the spotted fever group is circulating among dogs and cats in Natal.

Seroprevalence of vector-borne pathogens in dogs from Croatia.

Canine vector-borne pathogens (VBPs) are a group of globally distributed and rapidly spreading microorganisms transmitted by arthropods. In the present survey, we investigated Anaplasma spp., Ehrlichia canis, Dirofilaria immitis and Borrelia burgdorferi sensu lato seroprevalence between three groups of dogs (asymptomatic, suspected and deceased) from continental and coastal regions of Croatia with the commercial point-of-care SNAP®4Dx®Plus for VBPs. The overall prevalence for tested pathogens in dogs was 6.1% with the highest prevalence detected for Anaplasma spp. (4.5%), while the remaining pathogens were found at a prevalence of less than 1% (E. canis 0.6%, B. burgdorferi s.l. 0.4%, D. immitis 0.6%). No statistically significant differences in VBP detection between dog cohorts could be found with the exception of D. immitis in the deceased group. Interestingly, no evidence of D. immitis could be found in the hearts of dogs in this group at necropsy, however. This study provides the first data on the seroprevalence of selected VBPs between dogs of different health statuses in Croatia. The results demonstrate that serological evidence of VBPs alone or in combination with co-infections were found just as frequently in asymptomatic dogs as those with suspected or confirmed evidence of VBP disease, raising questions about the pathogenic potential of these organisms in domesticated dogs.

Serological survey of canine vector-borne diseases in Saskatchewan, Canada.

Whole blood samples were collected from 515 dogs in the practice region surrounding Saskatoon, Saskatchewan, Canada between 2008 and 2010 and evaluated for seroprevalence of vector-borne diseases. Of 515 samples, 12 (2.3%) were positive, with 7 (1.4%) positive for antibodies to Borrelia burgdorferi. These prevalences are higher than those previously reported for this region.

Enquête sérologique des maladies canines à transmission vectorielle en Saskatchewan, au Canada. Des échantillons de sang total ont été prélevés auprès de 515 chiens dans des établissements vétérinaires des environs de Saskatoon, en Saskatchewan, au Canada, entre 2008 et 2010, et ont été évalués pour la séroprévalence des maladies à transmission vectorielle. Parmi les 515 échantillons, 12 (2,3 %) étaient positifs et 7 (1,4 %) étaient positifs pour les anticorps contre Borrelia burgdorferi. Ces prévalences sont supérieures à celles précédemment signalées pour cette région.(Traduit par Isabelle Vallières).

Seroprevalence and current infections of canine vector-borne diseases in Nicaragua.

BACKGROUND: Vector-borne diseases constitute a major problem for veterinary and public health, especially in tropical regions like Central America. Domestic dogs may be infected with several vector-borne pathogens of zoonotic relevance, which may also severely compromise canine health. METHODS: To assess the prevalence of canine vector-borne diseases in Nicaragua, 329 dogs from seven cities, which were presented to the veterinarian for various reasons, were included in this study. Dogs were examined clinically and diagnostic blood samples were taken for analysis of packed cell volume (PCV) and presence of microfilariae as well as antigen of Dirofilaria immitis and antibodies to Ehrlichia spp., Anaplasma spp. and Borrelia burgdorferi (sensu lato) by use of a commercially available rapid ELISA. To detect current infections, specific PCRs for the detection of E. canis, A. platys and A. phagocytophilum were carried out on blood samples of the respective seropositive dogs. Microfilaremic blood samples, as well as D. immitis antigen positive samples were further subjected to PCR and subsequent sequencing for filarial species identification. RESULTS: Antibodies against Ehrlichia spp. were present in 62.9% of dogs, while Anaplasma spp. seroprevalence was 28.6%. Antibodies against species of both genera were detected in 24.9% of dogs. Borrelia burgdorferi (s.l.) antibodies were not detected. Dirofilaria immitis antigen was present in six animals (1.8%), two of which also showed D. immitis microfilariae in buffy coat. In addition to D. immitis, Acanthocheilonema reconditum was identified by PCR and sequencing in two of four additional microfilaremic blood samples, which were tested negative for D. immitis antigen. Current E. canis infections as defined by DNA detection were present in 58.5% of Ehrlichia-seropositive dogs, while 5.3% of Anaplasma-seropositive dogs were PCR-positive for A. platys, 2.2% for A. phagocytophilum and 16.0% for both Anaplasma species. Current E. canis infection had a statistically significant negative impact on PCV, whereas no relationship between infection status and clinical signs of disease could be observed. CONCLUSIONS: These results indicate that canine vector-borne diseases are widespread in Nicaragua and that dogs may constitute a reservoir for human infection with E. canis, A. phagocytophilum and D. immitis. Thus, the use of repellents or acaricides to protect dogs from vector-borne diseases is strongly recommended.

Detection of Dirofilaria immitis antigen and antibodies against Anaplasma phagocytophilum, Borrelia burgdorferi and Ehrlichia canis in dogs from ten provinces of China.

Despite the fact vector-borne diseases (VBDs) have been increasingly reported in dogs worldwide, there are only limited reports on VBDs in dogs in China with most being based on molecular detection of active infections. To provide further data on the exposure of dogs in China to VBD agents, we used commercial immunochromatographic assays to test plasma from 637 apparently healthy indoor and breeding colony dogs from 21 veterinary clinics in 10 provinces in China and a commercial dog breeding facility for circulating antigen of Dirofilaria immitis, and for circulating antibodies against Ehrlichia spp., Anaplasma spp., and Borrelia burgdorferi. Overall, we found only low levels of exposure to Ehrlichia spp. (4.7%; 30/637), Anaplasma spp. (1.4%; 9/637), B. burgdorferi (0.9%; 6/637) and D. immitis (0.2%; 1/637) with most of the positive animals coming from the commercial breeding colony (26/103; 25.2%) where ectoparasites were most commonly noted. At least one vector-borne agent was found in dogs from 6 of the 10 provinces investigated. Our results confirm exposure of dogs from around China to a variety of VBDs, even indoor pets seldom observed to harbor ectoparasites.

Does co-infection with vector-borne pathogens play a role in clinical canine leishmaniosis?

BACKGROUND: The severity of canine leishmaniosis (CanL) due to Leishmania infantum might be affected by other vector-borne organisms that mimic its clinical signs and clinicopathological abnormalities. The aim of this study was to determine co-infections with other vector-borne pathogens based on serological and molecular techniques in dogs with clinical leishmaniosis living in Spain and to associate them with clinical signs and clinicopathological abnormalities as well as disease severity. METHODS: Sixty-one dogs with clinical leishmaniosis and 16 apparently healthy dogs were tested for Rickettsia conorii, Ehrlichia canis, Anaplasma phagocytophilum and Bartonella henselae antigens by the immunofluorescence antibody test (IFAT) and for E. canis, Anaplasma spp., Hepatozoon spp., Babesia spp. and filarioid DNA by polymerase chain reaction (PCR). RESULTS: Among the dogs examined by IFAT, the seroprevalences were: 69% for R. conorii, 57% for E. canis, 44% for A. phagocytophilum and 37% for B. henselae; while the prevalences found by PCR were: 8% for Ehrlichia/Anaplasma, 3% for Anaplasma platys and 1% for H. canis. No other pathogen DNA was detected. Statistical association was found between dogs with clinical leishmaniosis and seroreactivity to R. conorii antigen (Fisher's exact test: P = 0.025, OR = 4.1, 95% CI = 1-17) and A. phagocytophilum antigen (Fisher's exact test: P = 0.002, OR = 14.3, 95% CI = 2-626) and being positive to more than one serological or molecular tests (co-infections) (Mann-Whitney test: U = 243, Z = -2.6, n 1 = 14, n 2 = 61, P = 0.01) when compared with healthy dogs. Interestingly, a statistical association was found between the presence of R. conorii, E. canis, A. phagocytophilum and B. henselae antibodies in sick dogs and some clinicopathological abnormalities such as albumin and albumin/globulin ratio decrease and increase in serum globulins. Furthermore, seroreactivity with A. phagocytophilum antigens was statistically associated with CanL clinical stages III and IV. CONCLUSIONS: This study demonstrates that dogs with clinical leishmaniosis from Catalonia (Spain) have a higher rate of co-infections with other vector-borne pathogens when compared with healthy controls. Furthermore, positivity to some vector-borne pathogens was associated with more marked clinicopathological abnormalities as well as disease severity with CanL.

Clinical evaluation of outdoor cats exposed to ectoparasites and associated risk for vector-borne infections in southern Italy.

BACKGROUND: Cats can be carriers of infected arthropods and be infected with several vector-borne pathogens (VBP) but there is limited knowledge about their pathogenic role in cats. RESULTS: A cross-sectional controlled study investigated the clinical status and antibody (Bartonella henselae, Rickettsia conorii, Ehrlichia canis, Anaplasma phagocytophilum, Babesia microti and Leishmania infantum) and/or blood PCR (Mycoplasma spp., Bartonella spp., Rickettsia spp., Ehrlichia/Anaplasma spp., piroplasmids, L. infantum, Hepatozoon felis) prevalence in 197 cats. Outdoor cats lacking ectoparasiticide treatment or hosting ectoparasites (study group [SG], n = 134) and indoor cats treated against ectoparasites (control group [CG], n = 63) were enrolled. Clinical data and retroviral co-infections were compared between the two groups. Multivariable analysis tested associations between variables and VBP exposure. Lymphadenia, stomatitis, and various haematological abnormalities were statistically more frequent in SG. Antibodies against R. conorii, B. henselae, A. phagocytophylum, B. microti, E. canis and L. infantum were detected. Bartonella henselae, Bartonella clarridgeiae, Mycoplasma haemofelis, "Candidatus Mycoplasma haemominutum" and "Candidatus Mycoplasma turicensis" DNA were identified. Very high antibody (87.8%) and PCR (40.1%) positivity to at least one pathogen were detected and were significantly higher in SG. Co-infections were confirmed in about one-third of the cats and were more frequent in SG cats. Molecular and overall (antibody and PCR) positivity to Bartonella and antibody positivity to R. conorii were higher in SG. Multivariable analysis found significant associations of Bartonella spp. infection with Feline Immunodeficiency Virus (FIV) infection and increased globulins, and of Mycoplasma spp. infection with adult age, FIV infection, anaemia, and increased creatinine. CONCLUSIONS: A very high prevalence of exposure to zoonotic VBP was found in cats, with Rickettsia and Bartonella infections being most prevalent. Some risk factors were documented namely for Mycoplasma spp. and Bartonella spp. The lifestyle of cats is clinically relevant and requires specific preventative measures to protect their health.

Ehrlichia spp. infection in rural dogs from remote indigenous villages in north-eastern Brazil.

BACKGROUND: Ehrlichia canis is a tick-borne bacterium that causes severe, life-threatening disease in dogs, being more prevalent in tropical and subtropical countries. Randomized studies conducted in Brazil indicate that the prevalence of E. canis infection in dogs ranges from 0.7% to over 50.0%. In a study conducted in northern Brazil, the prevalence was higher in dogs from urban areas, as compared to dogs from rural areas. In the present study, we investigated the exposure to Ehrlichia spp. infection in dogs from remote indigenous villages located in a rural area in north-eastern Brazil. METHODS: From March to June 2015, 300 privately owned dogs were blood sampled and tested by a rapid ELISA and by a conventional PCR in order to detect anti-Ehrlichia spp. antibodies and E. canis DNA, respectively. Additionally, dogs were also tested for anti-Anaplasma spp. antibodies and Anaplasma platys DNA, using the same diagnostic approaches. Positivity was correlated with tick infestation and dogs' data (gender, age and level of restriction). RESULTS: Overall, 212 (70.7%) dogs were positive for at least one test targeting Ehrlichia spp. In particular, 173 (57.7%) dogs were positive only by rapid ELISA, 5 (1.7%) only by PCR and 34 (11.4%) were simultaneously positive by both tests. In the same way, 39 (13.0%) dogs presented detectable E. canis DNA in their blood, whereas 18 (6.0%) dogs were A. platys DNA-positive. Coupling serological and PCR data, 63 (21.0%) dogs were simultaneously positive to Ehrlichia spp. and Anaplasma spp. Positivity rates for both Ehrlichia spp. and Anaplasma spp. were higher among dogs more than 1 year of age. Sick dogs were more positive to Ehrlichia spp. as compared to healthy dogs. CONCLUSIONS: Dogs from rural areas in north-eastern Brazil are highly exposed to Ehrlichia spp. infection and positivity rates do not necessarily correlate with current tick infestation load, since only one infected tick bite is needed to get the infection. This reinforces the importance of keeping dogs free of ticks, in order to reduce as much as possible the risk of infection by E. canis and other tick-borne pathogens such as Babesia vogeli, which are usually co-endemic.

[Occurrence of Ehrlichia canis in dogs living in Germany and comparison of direct and indirect diagnostic methods]. / Vorkommen von Ehrlichia canis bei in Deutschland lebenden Hunden sowie Vergleich direkter und indirekter Diagnostikmethoden.

OBJECTIVE: To study the occurrence of Ehrlichia (E.) canis in dogs living in Germany and evaluate the possibilities and limits of direct and indirect diagnostic methods. MATERIAL AND METHODS: The first part of the study was a retrospective analysis of routine samples, which had been examined for E. canis antibodies using an indirect immunofluorescence antibody test (IFAT). The examination was part of a laboratory profile for the detection of travel-related diseases (travel disease profile) or was performed on an individual basis. In the second part, samples which were examined within a travel disease profile, including E. canis antibodies, were further evaluated for E. canis DNA by a polymerase chain reaction (PCR). Medical histories were obtained of E. canis-positive dogs (animals which were positive in IFAT and/or PCR) and for a part of the negative animals. RESULTS: For 2015, 11.8% of 12220 samples had antibodies for E. canis. Dogs, which were examined with a travel disease profile, displayed antibodies in 5.6% cases of 1172 animals (investigation period February to March 2016). Of the E. canis-positive dogs (n = 67), 91% were positive with only the IFAT, 7.5% with the IFAT and PCR and 1.5% were only positive by PCR. Anamnesis showed that particularly imported dogs without symptoms were controlled for travel diseases during their first year in Germany. CONCLUSION AND CLINICAL RELEVANCE: Although endemic E. canis infections play a minor role in Germany, infections with this pathogen are still of importance in this country, particularly because of the import of dogs. Therefore, a medical history helps in early ehrlichiosis diagnosis and to start an adequate treatment. Pathogen detection in imported E. canis-seropositive dogs, which often did not display clinical symptoms in this study, was frequently negative in blood samples by PCR. The diagnostic method should be chosen depending on the disease phase and the underlying question (symptoms or preventive screening).