Intestinal parasites, including cestodes like Dipylidium caninum, are common in dogs in the United States of America (USA), but fecal flotation consistently, and, at times, dramatically, fails to identify many of these infections. To determine the extent to which including coproantigen testing for D. caninum would improve the identification of dogs infected with this cestode, we evaluated fecal samples from 877 dogs (589 pet and 288 from municipal shelters) from six USA states using zinc sulfate (specific gravity 1.24) fecal flotation with centrifugation along with coproantigen detection for Giardia sp., hookworms, ascarids, and Trichuris vulpis. For D. caninum, PCR of perianal swabs was included. Intestinal parasite infections were identified, using centrifugal fecal flotation or coproantigen, in 265 dogs (13.2 % pet, 64.9 % shelter). Dipylidium caninum infection was detected in 5.6 % of dogs with the combination of coproantigen and centrifugal fecal flotation, and 7.3 % of dogs when perianal swab results were included; prevalence varied by diagnostic method, population, and geographic region. In pet dogs, D. caninum infection was identified by fecal flotation (0), coproantigen (2.2 %), or perianal swabs (1.2 %). The same methods revealed infection in 0.3 %, 12.5 %, and 11.1 % of shelter dogs, respectively. Frequent use of praziquantel in shelter dogs (116/288; 40.3 %) may have reduced prevalence. Positive and negative agreement of D. caninum coproantigen with perianal swab PCR in pet dogs was 85.7 % and 98.8 %, respectively. Multiple logistic regression analysis accounting for region, population, and age found D. caninum infection to be more common in shelter dogs relative to pet (adjusted OR 4.91 [2.48, 10.24]) and in the Southcentral and Southeast regions relative to North (adjusted OR 9.59 [1.92, 174.13] and 17.69 [3.67, 318.09] respectively). Coproantigen testing also enhanced the detection of other intestinal parasites over fecal flotation alone, including Giardia sp. (14.7 % vs 3.3 %), hookworms (13.8 % vs 8.4 %), ascarids (2.9 % vs 2.2 %), and T. vulpis (2.9 % vs 1.4 %). Together, these data indicate that the coproantigen assay employed increases detection of D. caninum infections several fold, supporting the use of this test in clinical practice, and add to a growing body of research documenting enhanced diagnosis through implementation of multiple laboratory-based methods.

Dipylidium caninum infections in dogs and cats are underestimated because of a lack of proglottid observations and poor recovery of parasite elements by centrifugal flotation. We developed an immunoassay that employs a pair of monoclonal antibodies to capture D. caninum–specific coproantigen in fecal extracts from dogs and cats. Real-time PCR for D. caninum DNA in perianal swabs and observation of proglottids were used as reference methods. In 6 experimentally infected dogs, parasite DNA, coproantigen, and proglottid segments were first detected at 22, 23, and 26 d post-infection, respectively. Praziquantel treatment of 3 experimentally infected dogs resulted in the elimination of both coproantigen and proglottid shedding within 1–5 d post-treatment; however, parasite DNA persisted for 14 d. Immunohistochemistry on immature and mature tapeworm segments using an antibody against the coproantigen supports the premise that the antigen is produced in mature segments. We assessed the performance of our coproantigen test in natural infections in 78 dogs from a flea-endemic area. Of the 12 antigen-positive samples, 11 were confirmed with a positive PCR test and/or proglottid observation. Finally, we evaluated a convenience sample set of 730 canine and 163 feline fecal samples obtained from a commercial diagnostic laboratory; D. caninum antigen was detected in 4.1% of the canine and 12.9% of the feline samples, whereas parasite elements were observed in only 0.028% of samples. Our coproantigen immunoassay provides a sensitive method for the detection of D. caninum infection in dogs and cats.

Dipylidium caninum infections in dogs and cats are underestimated because of a lack of proglottid observations and poor recovery of parasite elements by centrifugal flotation. We developed an immunoassay that employs a pair of monoclonal antibodies to capture D. caninum– specific coproantigen in fecal extracts from dogs and cats. Real-time PCR for D. caninum DNA in perianal swabs and observation of proglottids were used as reference methods. In 6 experimentally infected dogs, parasite DNA, coproantigen, and proglottid segments were first detected at 22, 23, and 26 d post-infection, respectively. Praziquantel treatment of 3 experimentally infected dogs resulted in the elimination of both coproantigen and proglottid shedding within 1–5 d post-treatment; however, parasite DNA persisted for 14 d. Immunohistochemistry on immature and mature tapeworm segments using an antibody against the coproantigen supports the premise that the antigen is produced in mature segments. We assessed the performance of our coproantigen test in natural infections in 78 dogs from a flea-endemic area. Of the 12 antigen-positive samples, 11 were confirmed with a positive PCR test and/or proglottid observation. Finally, we evaluated a convenience sample set of 730 canine and 163 feline fecal samples obtained from a commercial diagnostic laboratory; D. caninum antigen was detected in 4.1% of the canine and 12.9% of the feline samples, whereas parasite elements were observed in only 0.028% of samples. Our coproantigen immunoassay provides a sensitive method for the detection of D. caninum infection in dogs and cats. Keywords antigen , canine , cestode , feline , flea , tapeworm

Lyme disease (LD) due to Borrelia burgdorferi is the most prevalent vector-borne disease in the United States. There is a poor understanding of how immunity contributes to bacterial control, pathology, or both during LD. Dogs in an area of endemicity were screened for B. burgdorferi and Anaplasma exposure and stratified according to seropositivity, presence of LD symptoms, and doxycycline treatment. Significantly elevated serum interleukin-21 (IL-21) and increased circulating CD3+ CD94+ lymphocytes with an NK-like CD8+ T cell phenotype were predominant in asymptomatic dogs exposed to B. burgdorferi. Both CD94+ T cells and CD3- CD94+ lymphocytes, corresponding to NK cells, from symptomatic dogs expressed gamma interferon (IFN-γ) at a 3-fold-higher frequency upon stimulation with B. burgdorferi than the same subset among endemic controls. Surface expression of activating receptor NKp46 was reduced on CD94+ T cells from LD, compared to cells after doxycycline treatment. A higher frequency of NKp46-expressing CD94+ T cells correlated with significantly increased peripheral blood mononuclear cell (PBMC) cytotoxic activity via calcein release assay. PBMCs from dogs with symptomatic LD showed significantly reduced killing ability compared with endemic control PBMCs. An elevated NK-like CD8+ T cell response was associated with protection against development of clinical LD, while excess IFN-γ was associated with clinical disease.

Objectives The aims of this study were to experimentally inoculate cats with Cryptosporidium felis oocysts and compare fecal detection by fluorescent antibody assay (FA) and quantitative PCR (qPCR), and document clinical signs associated with infection. Methods Cryptosporidium felis oocysts were concentrated from the feces of a naturally infected cat and orally inoculated into six cats that tested negative for C felis by an FA and fecal flotation (FF). Cats were observed daily for the presence of clinical signs consistent with infection. Fecal samples from all cats on days 0 and 9, and one sample per cat (days 18–21), were evaluated by all assays. On day 31, two cats negative for C felis by FF and FA were administered methylprednisolone acetate and all assays were repeated on days 34, 36 and 38. Samples from all cats were tested by FF and FA on days 41, 43, 45 and 48. Results A total of 41 samples were tested, 25 of which were compared by FA and qPCR. Cryptosporidium felis was detected in 2/25 (8%) and in 19/25 (76%) samples by FA and by qPCR, respectively; the other 16 samples were tested by FF and FA. None of the cats was positive for C felis by FF or FA in samples collected on days 0, 9 or 18–21. One, five and six samples tested positive by qPCR on days 0, 9 and 18–21, respectively. The cats administered methylprednisolone acetate tested positive for C felis by FA on day 36 and by qPCR on days 31, 34, 36 and 38. None of the cats showed clinical signs of disease. Conclusions and relevance Clinical signs were not recognized in any of the cats for the duration of the study. FA was insensitive compared with qPCR for detecting cats with subclinical C felis infection. Keywords , , qPCR , experimental infection , direct fluorescent assay

Cystoisospora felis is a common parasite of cats and is diagnosed by fecal flotation, but false-negative results can be common. To experimentally inoculate cats with C. felis oocysts, to compare fecal flotation and polymerase chain reaction (PCR) results, and to describe any clinical signs consistent with infection. Six cats. Cystoisospora felis oocysts were identified morphologically from feces of a naturally infected kitten with diarrhea, sporulated oocysts (5000) were inoculated to 6 cats that were negative for fecal parasites by fecal flotation and by a fluorescent antibody assay (FA) for Giardia spp. and Cryptosporidium spp. Cats were observed daily for the presence of clinical signs consistent with infection. Fecal samples were evaluated by fecal flotation and FA up to 3 times per week post inoculation (PI) to Day 27. Thirty-six samples collected before inoculation and from Days 8, 10, 13, 15, and 20 PI were assayed using an internal transcribed spacer 1 (ITS1) PCR that amplifies DNA of C. felis . All cats were negative for C. felis by both assays before inoculation. All cats shed C. felis oocysts by Day 10 PI, oocysts were not detected by fecal flotation after Day 15 PI. Cystoisospora felis DNA was amplified from 24/36 (66.6%) fecal samples from 6/6 (100%) of the cats. Oocysts were not detected by fecal flotation in 4 of the samples that were positive for C. felis DNA by PCR. Clinical signs were not recognized in any of the study cats. Fecal flotation is a convenient assay for detection of C. felis but could occasionally give false-negative results when compared to this ITS1 PCR.

The common signs of canine babesiosis caused by an infection with Babesia canis are fever, anorexia, lethargy, pulse alterations, anemia, and occasionally mild icterus. Dogs with these clinical signs can be divided into two groups: those with acute-phase reaction and those with systemic inflammatory response syndrome (SIRS). Factors associated with the occurrence of SIRS in canine babesiosis have not been thoroughly researched. This article outlines a cross-sectional study of 54 client-owned dogs with an acute B. canis infection, and evaluates the differences in age, gender, laboratory findings, parasite load, and seroreactivity against B. canis between the SIRS and the SIRS-free dogs. We have analyzed a complete blood count, serum biochemistry, serum amyloid A, ceruloplasmin, paraoxonase-1, serology, and PCR testing using standard methodologies. The frequency of SIRS among the investigated dogs reached 0.59. Male dogs and those seronegative against B. canis, were more frequent in the SIRS group, whilst age and parasite load could not be associated with the presence of SIRS. Dogs with SIRS had a lower count of total leukocytes, neutrophils, lymphocytes, and monocytes, and a lower concentration of iron and bilirubin compared with SIRS-free dogs. No significant differences in the concentration of acute-phase proteins have been noticed to exist between the groups of dogs. Further, the seronegative dogs had a lower count of lymphocytes and monocytes and a higher parasite load than the seroreactive dogs. Multivariate logistic regression analysis has identified leukopenia (<6 × 109/L) and monocytopenia (<0.2 × 109/L) as independent associates of SIRS in the investigated dogs, thus implying that these routine tests could be used as reliable markers for SIRS.

In September 2018, a four-month-old dog with fever and petechial bleeding came to the internal clinic at the Faculty of Veterinary Medicine University of Belgrade. On hematology analysis, thrombocytopenia and mild anemia were observed. Examination of the blood smear revealed platelet inclusions. The commercial serology test was positive for Anaplasma spp. The dog was treated with doxycycline for 14 days, and after 48 hours from the beginning of the treatment, the symptoms subsided. PCR analysis and sequencing confirmed infection with A. platys .

Objectives The aims of this study were to experimentally inoculate cats with Cryptosporidium felis oocysts and compare fecal detection by fluorescent antibody assay (FA) and quantitative PCR (qPCR), and document clinical signs associated with infection. Methods Cryptosporidium felis oocysts were concentrated from the feces of a naturally infected cat and orally inoculated into six cats that tested negative for C felis by an FA and fecal flotation (FF). Cats were observed daily for the presence of clinical signs consistent with infection. Fecal samples from all cats on days 0 and 9, and one sample per cat (days 18–21), were evaluated by all assays. On day 31, two cats negative for C felis by FF and FA were administered methylprednisolone acetate and all assays were repeated on days 34, 36 and 38. Samples from all cats were tested by FF and FA on days 41, 43, 45 and 48. Results A total of 41 samples were tested, 25 of which were compared by FA and qPCR. Cryptosporidium felis was detected in 2/25 (8%) and in 19/25 (76%) samples by FA and by qPCR, respectively; the other 16 samples were tested by FF and FA. None of the cats was positive for C felis by FF or FA in samples collected on days 0, 9 or 18–21. One, five and six samples tested positive by qPCR on days 0, 9 and 18–21, respectively. The cats administered methylprednisolone acetate tested positive for C felis by FA on day 36 and by qPCR on days 31, 34, 36 and 38. None of the cats showed clinical signs of disease. Conclusions and relevance Clinical signs were not recognized in any of the cats for the duration of the study. FA was insensitive compared with qPCR for detecting cats with subclinical C felis infection.

Hepatozoon canis is a hemoprotozoan organism that infects domestic and wild carnivores throughout much of Europe. The parasite is mainly transmitted through the ingestion of infected ticks containing mature oocysts. The aims of the present survey were to determine the prevalence of H. canis in hunting dogs living in Southern Italy and to assess potential infection risk factors. DNA extracted from whole blood samples, collected from 1433 apparently healthy dogs living in the Napoli, Avellino, and Salerno provinces of Campania region (Southern Italy), was tested by a quantitative real-time polymerase chain reaction (qPCR) assay to amplify H. canis. Furthermore, the investigated dog population was also screened by qPCR for the presence of Ehrlichia canis , a major tick-borne pathogen in Southern Italy, in order to assess possible co-infections. Two hundred dogs were H. canis PCR-positive, resulting in an overall prevalence of 14.0% (CI 12.2–15.9). Breed category ( P < 0.0001), hair coat length ( P = 0.015), and province of residence ( P < 0.0001) represented significant risk factors for H. canis infection. The presence of H. canis DNA was also significantly associated with E. canis PCR positivity ( P < 0.0001). Hunting dogs in Campania region (Southern Italy) are frequently exposed to H. canis , and the infection is potentially associated with close contact with wildlife. Further studies are needed to assess the pathogenic potential of H. canis , as well as the epidemiological relationships between hunting dogs and wild animal populations sharing the same habitats in Southern Italy.

BACKGROUND:Both incidence and geographical range of tick-borne disease has increased across the USA. Similar to people, dogs are hosts for Anaplasma spp., Babesia spp., Ehrlichia spp. and Borrelia burgdorferi. Dogs also share our homes and beds, making them both a sentinel for the ticks in our backyards but also increasing our exposure to ticks. Measures to better track, prevent, and/or treat tick-borne diseases in companion animals can lead to better control and prevention of human tick-borne disease. This study identifies demographic and co-infection risk factors for canine seropositivity to tick-borne infections in a cohort of hunting dogs across the USA. RESULTS:Human patterns of tick-borne disease co-infection in the USA have been predominantly driven by the geographical distribution of the tick vector. Dogs who tested seropositive for Anaplasma spp. were 1.40 times more likely (P = 0.0242) to also test seropositive for Babesia spp. and vice versa (1.60 times more likely, P = 0.0014). Dogs living in the West had 5% lower risk (P = 0.0001) for Ehrlichia spp. seropositivity compared to other regions. Controlling for age and Anaplasma spp. seroprevalence, dogs in all three other regions were 2.30 times more likely (P = 0.0216) to test seropositive for B. burgdorferi than dogs in the West. Dogs seropositive for B. burgdorferi were 1.60 times more likely (P = 0.0473) to be seropositive for Anaplasma spp. CONCLUSIONS:Tick geographical distributions have a prominent impact on the regional distribution of hunting dog exposure to tick-borne diseases. Education concerning regional tick prevalence and disease risk is important for everyone, but particularly dog owners, regarding ticks in their region and protection from infection and co-infection of tick-borne pathogens as they travel or move with their dogs. Dogs are sentinel species for human exposure to ticks, and as such surveillance of canine tick-borne infections and understanding the probability that these infections might be seen together as co-infections helps predict emerging areas where people are more likely to be exposed as well.

Mycoplasma haemocanis (Mhc) and "Candidatus Mycoplasma haematoparvum" (CMhp) are the main haemoplasma species known to infect dogs. The aim of this study was to determine the prevalence of haemoplasma species infections in hunting dogs from southern Italy and assess related risk factors. 1,433 hunting dogs living in Campania region were tested by qPCR assay. The prevalence was 19.9 %; 13.1 % for Mhc and 11.4 % for CMhp; 4.6 % showed a coinfection with both haemoplasma species. Statistical analysis revealed living in Salerno province (Mhc: OR 3.72; CMhp: OR 2.74), hound (Mhc: OR 5.26; CMhp: OR 8.46) and mixed breed (Mhc: OR 3.38; CMhp: OR 2.80), rural environment (Mhc: OR 12.58; CMhp: OR 10.38), wild mammal hunting (Mhc: OR 8.73; CMhp: OR 8.32), cohabitation with other animals (Mhc: OR 2.82; CMhp: OR 2.78) and large pack size (Mhc: OR 2.96; CMhp: OR 1.61) as risk factors for haemoplasmas. Male gender (OR 1.44) and tick infestation history (OR 1.40) represented risk factors only for Mhc, while adult age (2-7 years OR 2.01; 7 years OR 1.84) and large body size (OR 1.48) were associated only to CMhp. Mhc infection was significantly associated to Babesia vogeli (p < 0.05) and Hepatozoon canis (p < 0.001), while CMhp with H. canis (p < 0.001). This study adds information on haemoplasma species distribution in hunting dogs in southern Italy. Outdoor lifestyle and contact with wild fauna, through greater exposure to tick infestation, or possibly wounds acquired during hunting or fighting, could be factors contributing to haemoplasma infections.

Background Cystoisospora felis is a common parasite of cats and is diagnosed by fecal flotation, but false-negative results can be common. Hypothesis/Objectives To experimentally inoculate cats with C. felis oocysts, to compare fecal flotation and polymerase chain reaction (PCR) results, and to describe any clinical signs consistent with infection. Animals Six cats. Methods Cystoisospora felis oocysts were identified morphologically from feces of a naturally infected kitten with diarrhea, sporulated oocysts (5000) were inoculated to 6 cats that were negative for fecal parasites by fecal flotation and by a fluorescent antibody assay (FA) for Giardia spp. and Cryptosporidium spp. Cats were observed daily for the presence of clinical signs consistent with infection. Fecal samples were evaluated by fecal flotation and FA up to 3 times per week post inoculation (PI) to Day 27. Thirty-six samples collected before inoculation and from Days 8, 10, 13, 15, and 20 PI were assayed using an internal transcribed spacer 1 (ITS1) PCR that amplifies DNA of C. felis. Results All cats were negative for C. felis by both assays before inoculation. All cats shed C. felis oocysts by Day 10 PI, oocysts were not detected by fecal flotation after Day 15 PI. Cystoisospora felis DNA was amplified from 24/36 (66.6%) fecal samples from 6/6 (100%) of the cats. Oocysts were not detected by fecal flotation in 4 of the samples that were positive for C. felis DNA by PCR. Clinical signs were not recognized in any of the study cats. Conclusions and Clinical Importance Fecal flotation is a convenient assay for detection of C. felis but could occasionally give false-negative results when compared to this ITS1 PCR.

Better tools are necessary to eliminate visceral leishmaniasis (VL). Modeling studies for regional Leishmania elimination indicate that an effective vaccine is a critical tool. Dogs are the reservoir host of L infantum in Brazil and the Mediterranean basin, and therefore are an important target for public health interventions as well as a relevant disease model for human VL. No vaccine has been efficacious as an immunotherapy to prevent progression of already diagnostically positive individuals to symptomatic leishmaniasis. We performed a double-blinded, block-randomized, placebo-controlled, vaccine immunotherapy trial testing the efficacy of a recombinant Leishmania A2 protein, saponin-adjuvanted, vaccine, LeishTec (R), in owned hunting dogs infected with L. infantum. The primary outcome was reduction of clinical progression, with reduction of mortality as a secondary outcome. Vaccination as an immunotherapy reduced the risk of progression to clinically overt leishmaniasis by 25% in asymptomatic dogs (RR: 1.33 95% C.I. 1.009-1.786 p-value: 0.0450). Receiving vaccine vs. placebo reduced all-cause mortality in younger asymptomatic dogs by 70% (RR: 3.19 95% C.I.: 1.185-8.502 p-value = 0.0245). Vaccination of infected-healthy animals with an anti-Leishmania vaccine significantly reduced clinical progression and decreased all-cause mortality. Use of vaccination in infected-healthy dogs can be a tool for Leishmania control. (C) 2018 Elsevier Ltd. All rights reserved.

Canine babesiosis is caused by haemoprotozoan organisms of the genus Babesia which are transmitted by the bite of a hard tick. The aim of this survey was to determine the prevalence and risk factors associated with Babesia species infections in hunting dogs from Southern Italy. Blood samples were collected from 1311 healthy dogs in the Napoli, Avellino and Salerno provinces of the Campania region of Southern Italy. Serological testing was performed using two enzyme-linked immunosorbent assays (ELISA), with one designed to detect B. canis and B. vogeli antibodies, and the other designed to detect B. gibsoni antibodies. Blood samples were also tested by quantitative real-time polymerase chain reaction (qPCR) assays for amplification of B. canis, B. vogeli and B. gibsoni DNA. The overall seroprevalence for B. canis/B. vogeli was 14.0%, compared to 0.2% for B. gibsoni. B. canis and B. vogeli PCR positive rates were 0.15% and 1.1%, respectively. B. gibsoni DNA was not amplified by qPCR. Male gender (OR 1.85), increased age (OR 1.01), long hair coat (OR 1.61) and living in Salerno province (OR 1.71) represented risk factors for B. canis/B. vogeli seroreactivity. Hunting dogs in Southern Italy are often exposed to B. canis/B. vogeli, however Babesia spp. infection was infrequently detected using qPCR. Further studies are needed to determine the extent to which Babesia spp. cause clinical disease in hunting dogs, and to evaluate the potential epidemiological relationships between hunting dogs and wild animal populations sharing the same area.

Data concerning combined molecular and serological prevalence of emerging canine tick-borne pathogens in Serbia are lacking. A large population of outdoor living dogs in Belgrade, Serbia's' capital, present an excellent population for epidemiology study. Blood samples were collected from 111 dogs, including 46 shelter, 31 free roaming, and 34 hunting dogs. Species-specific real-time polymerase chain reaction (PCR) (IDEXX Laboratories, Inc., Westbrook Maine, USA) was applied for the molecular detection of Anaplasma phagocytophilum, A. platys, Ehrlichia canis, Babesia canis, B. gibsoni and B. vogeli. A research based SNAP assay (SNAP® M-A, IDEXX Laboratories, Inc., Westbrook Maine, USA) that uses genus and species-specific peptides was used to asses Anaplasma spp., A. phagocytophilum, A. platys, Ehrlichia spp., E. canis, E. chaffeensis, E. ewingii and Borrelia burgdorferi antibody status. B. canis, B. gibsoni and B. vogeli antibody status was assessed with an indirect immunofluorescence test (MegaCor Diagnostic, Horbranz, Austria). Anaplasma spp. and Ehrlichia spp. DNA was not amplified. One quarter of the dogs were A. phagocytophilum, one dog was A. platys, one was E. ewingii and two dogs were B. burgdorferi seroreactive with the SNAP® M-A. Babesia canis or B. gibsoni DNA was amplified by PCR from 16.2% of dogs, whereas 67.6% were seroreactive to one or more Babesia spp. Babesia vogeli was not PCR amplified. We conclude that outdoor dogs in this territory are reservoirs for B. canis and B. gibsoni and are frequently co-exposed to combinations of Anaplasma and Babesia spp.

Anaplasma phagocytophilum and Borrelia burgdorferi are both transmitted by Ixodes spp. and are associated with clinical illness in some infected dogs. This study evaluated canine antibody responses to the A. phagocytophilum p44 peptides APH-1 and APH-4 as well as the B. burgdorferi C6 peptide before and after doxycycline treatment. A total of eight dogs were infested with wild-caught I. scapularis for 1 week. Blood was collected prior to tick attachment and from Days 3-77 to 218-302 with doxycycline treatment beginning on Day 218. Blood was assayed for A. phagocytophilum DNA by PCR assay. Sera was assessed for antibodies by immunofluorescent antibody (IFA) test and ELISA. Anaplasma phagocytophilum DNA was amplified from blood of all dogs by Day 7. Antibodies to APH-4 were detected in serum as early as 14 days after tick exposure and six dogs had APH-4 antibodies detected 3-7 days before antibodies against APH-1. All dogs were seropositive for A. phagocytophilum from Days 218 to 302. Antibodies to B. burgdorferi were detected in 6/8 dogs beginning 21 days after I. scapularis infestation. Among the five dogs that remained seropositive at Day 218, C6 antibody levels declined on average 81% within 84 days of initiating treatment. The results suggest that the APH-4 peptide may be more useful than APH-1 for detecting antibodies earlier in the course of an A. phagocytophilum infection. After doxycycline administration, C6 antibody levels but not APH-1 or APH-4 antibody levels decreased, suggesting a treatment effect on C6 antibody production. (C) 2017 The Author(s). Published by Elsevier Ltd.

Background Ehrlichia ewingii , which causes disease in dogs and people, is the most common Ehrlichia spp. infecting dogs in the United States, but little is known about how long E . ewingii infection persists in dogs. Hypothesis/Objectives To evaluate the persistence of natural infection with E. ewingii in dogs. Animals Four Class A Beagles; no previous exposure to ticks or tick‐borne infectious agents. Methods Dogs were exposed to ticks by weekly walks through tick habitat in north central Oklahoma; dogs positive for infection with Ehrlichia spp. by sequence‐confirmed PCR and peptide‐specific serology were evaluated for 733 days (D). Whole blood was collected once weekly for PCR , and serum was collected once monthly for detection of antibodies to Ehrlichia canis (peptide p16), Ehrlichia chaffeensis (indirect fluorescence antibody [ IFA ] and variable‐length PCR target [ VLPT ]), and E. ewingii (peptide p28). Results All dogs (4/4) became infected with Ehrlichia spp. as evidenced by seroconversion on IFA to E. chaffeensis (4/4); PCR detection of E. ewingii (4/4) and E. chaffeensis (2/4) DNA using both nested and real‐time assays; and presence of specific antibodies to E. ewingii (4/4) and E. chaffeensis (2/4). Infection with E. chaffeensis was not detected after D55. Intermittent E. ewingii rickettsemia persisted in 3 of 4 dogs for as long as 733 days. Conclusions and Clinical Importance Our data demonstrate that dogs infected with E. ewingii from tick feeding are capable of maintaining infection with this pathogen long‐term, and may serve as a reservoir host for the maintenance of E. ewingii in nature.

Dogs exposed to ticks in the southern US may become infected with multiple species of Ehrlichia. To better define infection risk, blood samples collected from 10 dogs infested with ticks via a natural infestation model were evaluated by blood smear examination, PCR, patient-side ELISAs (SNAP® 4Dx® and SNAP® 4Dx® Plus), IFA, and peptide based ELISA for evidence of infection with Ehrlichia canis, E. chaffeensis, and/or E. ewingii. Although morulae were rarely identified in blood smears, every dog (10/10) became infected with Ehrlichia spp. as evidenced by nested PCR detection of E. chaffeensis (7/10) and E. ewingii DNA (10/10); real-time PCR detection of E. chaffeensis (0/10) and E. ewingii (9/10); seroconversion on two different patient-side ELISAs (4/10 or 10/10); seroconversion on IFA to E. canis (10/10, maximum inverse titer=128-4096, GMTMAX=548.7) and E. chaffeensis (10/10, maximum inverse titer=1024-32,768, GMTMAX=4096); and seroconversion on peptide specific ELISA to E. chaffeensis VLPT (7/10) and E. ewingii p28 (9/10). Rickettsemia with E. chaffeensis and E. ewingii, as determined by nested PCR, persisted in dogs for an average of 3.2 or 30.5 days, respectively. Ehrlichia canis was not detected in any dog by any method, and no dogs developed signs of clinical disease. Our data suggest that in areas where ticks are common, dogs are at high risk of infection with Ehrlichia spp., particularly E. ewingii and E. chaffeensis, and can serve as a sentinel for monitoring for the presence of these zoonotic pathogens.

BACKGROUNDBased on the high tick-borne pathogen results from a 2011 surveillance study in three Colombian cities, an in-depth point prevalence survey was conducted to determine the seroprevalence of tick-borne pathogens at a specific point in time in 70 working dogs, 101 shelter dogs, and 47 client-owned dogs in Barranquilla, Colombia.RESULTSOf the 218 serum samples, 163 (74%) were positive for Ehrlichia canis and 116 (53%) for Anaplasma platys. Exposure to tick-borne pathogens was highest in shelter and working dogs where more than 90% of the samples were seropositive or positive on polymerase chain reaction for one or more organisms as compared to 51% in client-owned animals.CONCLUSIONSurveillance for exposure to tick-borne pathogens provides vital information necessary to protect and conserve the health of local humans and animals, deployed military service members, and working dogs in various parts of the world. This study and resultant data demonstrate the value of following a broad-based surveillance study with a more specific, focused analysis in an area of concern. This area?s high levels of exposure warrant emphasis by medical planners and advisors on precautionary measures for military dogs, Special Operations Forces personnel, and the local public.