Coinfection with multiple tick-borne pathogens in a Walker Hound kennel in North Carolina

Detection of Anaplasma spp. and Ehrlichia spp. in dogs from a veterinary teaching hospital in Italy: a retrospective study 2012-2020

Anaplasma phagocytophilum, Anaplasma platys and Ehrlichia canis, responsible of diseases in dogs, are tick-borne pathogens with a proven or potential zoonotic role that have shown increasing prevalence worldwide. The aims of this retrospective study were to assess the frequency of Anaplasma spp. and Ehrlichia spp. exposure in dogs tested in a veterinary teaching hospital in Italy over a 9-year period, to compare the performance of the diagnostic tests used, to evaluate correlations with clinical data, and to genetically analyse the identified bacteria. During the study period, 1322 dogs tested by at least one of the rapid immunoenzymatic test, indirect immunofluorescent antibody test or end-point PCR assay for Anaplasmataceae detection were included. Dogs were tested if they had clinical signs or clinicopathological alteration or risk factors related to infection, and if they were potential blood-donor animals. Ninety-four of 1322 (7.1%) dogs tested positive for at least one pathogen: 53 (4.3%) for A. phagocytophilum, one (0.1%) for A. platys and 63 (4.6%) for E. canis. The number of dogs tested increased and the positivity rate progressively declined over the years. Comparison of tests showed a near-perfect agreement between serological tests and a poor agreement between PCR and indirect assays. A breed predisposition has been highlighted for A. phagocytophilum infection in hunting breed dogs and for E. canis infection in mixed breed dogs. Phylogeny confirmed potential zoonotic implications for A. phagocytophilum and showed no correlation of the identified bacteria with the geographical origin. Our study provides new insights into possible risk factors in dogs and evidenced discordant results between different tests, suggesting that a combination of serological and molecular assays is preferable for a correct diagnosis.

Molecular survey of canine tick-borne pathogens in ticks and stray dogs in Dhaka city, Bangladesh

Molecular surveillance of canine tick-borne pathogens (TBPs) in Bangladesh has constantly been undervalued. Therefore, the emergence of new pathogens often remains undetected. This study aimed to screen tick-borne pathogens in stray dogs and ticks in the Dhaka metropolitan area (DMA). Eighty-five dog blood and 53 ticks were collected in six city districts of DMA from September 2022 to January 2023. The ticks were identified by morphology. Screening of TBPs was performed by polymerase chain reaction (PCR), followed by sequencing. The PCR assays were conducted to analyze the 18S rRNA (Babesia gibsoni, B. vogeli, and Hepatozoon canis), 16S rRNA (Anaplasma phagocytophilum, A. platys, and A. bovis), gltA (Ehrlichia canis and Rickettsia spp.), flagellin B (Borrelia spp.) and 16-23S rRNA (Bartonella spp.). Three tick species, Rhipicephalus sanguineus (50/53), R. microplus (1/53), and Haemaphysalis bispinosa (2/53), were identified. Babesia gibsoni (38 out of 85) and A. platys (7 out of 85) were detected in dog blood. In contrast, four pathogens, B. gibsoni (1 out of 53), B. vogeli (1 out of 53), H. canis (22 out of 53), and A. platys (1 out of 53), were detected in the ticks. However, the detection rates of TBPs in dog blood and ticks were not correlated in this study. The phylogenetic analyses suggested that a single genotype for each of the four pathogens is circulating in DMA. This study reports the existence of B. vogeli, H. canis, and A. platys in Bangladesh for the first time.

Investigating in vivo Mycobacterium avium subsp. paratuberculosis microevolution and mixed strain infections

Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne's Disease (JD) in ruminants, which is responsible for significant economic loss to the global dairy industry. Mixed strain infection (MSI) refers to the concurrent infection of a susceptible host with genetically distinct strains of a pathogen, whereas within-host changes in an infecting strain leading to genetically distinguishable progeny is called microevolution. The two processes can influence host-pathogen dynamics, disease progression and outcomes, but not much is known about their prevalence and impact on JD. Therefore, we obtained up to 10 MAP isolates each from 14 high-shedding animals and subjected them to whole-genome sequencing. Twelve of the 14 animals examined showed evidence for the presence of MSIs and microevolution, while the genotypes of MAP isolates from the remaining two animals could be attributed solely to microevolution. All MAP isolates that were otherwise isogenic had differences in short sequence repeats (SSRs), of which SSR1 and SSR2 were the most diverse and homoplastic. Variations in SSR1 and SSR2, which are located in ORF1 and ORF2, respectively, affect the genetic reading frame, leading to protein products with altered sequences and computed structures. The ORF1 gene product is predicted to be a MAP surface protein with possible roles in host immune modulation, but nothing could be inferred regarding the function of ORF2. Both genes are conserved in Mycobacterium avium complex members, but SSR1-based modulation of ORF1 reading frames seems to only occur in MAP, which could have potential implications on the infectivity of this pathogen. IMPORTANCE Johne's disease (JD) is a major problem in dairy animals, and concerns have been raised regarding the association of Mycobacterium avium subsp. paratuberculosis (MAP) with Crohn's disease in humans. MAP is an extremely slow-growing bacterium with low genome evolutionary rates. Certain short sequence repeats (SSR1 and SSR2) in the MAP chromosome are highly variable and evolve at a faster rate than the rest of the chromosome. In the current study, multiple MAP isolates with genetic variations such as single-nucleotide polymorphisms, and more noticeably, diverse SSRs, could simultaneously infect animals. Variations in SSR1 and SSR2 affect the products of the respective genes containing them. Since multiple MAP isolates can infect the same animal and the possibility that the pathogen undergoes further changes within the host due to unstable SSRs, this could provide a compensative mechanism for an otherwise slow-evolving pathogen to increase phenotypic diversity for overcoming host responses.

Co-infections of major tick-borne pathogens of dogs in Andhra Pradesh, South India

Implementing hemoprotozoan control strategies in dogs has become difficult because of the co-infections. A multiplex polymerase chain reaction (PCR) was carried out for simultaneous detection of the co-infections of Babesia gibsoni, B. vogeli, Hepatozoon canis and Ehrlichia canis from dogs (N = 442) in Andhra Pradesh, South India. The co-infection combinations were classified as (i) B. gibsoni + B. vogeli + E. canis + H. canis (BEH), (ii) B. gibsoni + B. vogeli + E. canis (BE), (iii) B. gibsoni + B. vogeli + H. canis (BH) and (iv) E. canis + H. canis (EH) groups. The parasite-specific multiplex PCR amplified 18S rRNA gene of B. gibsoni, B. vogeli and H. canis and VirB9 gene of E. canis. The age, gender, breed, medium, living condition and region of dogs were studied as risk factors for co-infections using logistic regression model. Among the co-infections, the incidence was 1.81%, 9.28%, 0.69% and 0.90% for BEH, BE, BH and EH infections, respectively. Young age (< one year), females, mongrels, rural dogs, kennel dogs and presence of ticks were the identified risk factors for overall prevalence of tick-borne pathogens. The incidence of infection was less in rainy season, especially in dogs with a previous acaricidal treatment. The study concludes that the multiplex PCR assay could simultaneously detect natural co-infections in dogs, emphasizing the need for the assay in epidemiological studies to reveal the real pattern of pathogens and select pathogen-specific treatment protocols.

Molecular Detection and Phylogenetic Characterization of Anaplasma spp. in Dogs from Hainan Province/Island, China

Anaplasmosis is a serious infection which is transmitted by ticks and mosquitos. There are very few reports and studies that have been carried out to understand the prevalence, distribution, and epidemiological profile of Anaplasma spp. infection in dogs in Hainan province/island. In the present study, we have tried to understand the prevalence, distribution, and occurrence of Anaplasma spp. infections in dogs (n = 1051) in Hainan Island/Province to establish a surveillance-based study. The confirmed positive samples by Polymerase chain reaction (PCR) were subjected to capillary sequencing for further strain-specific confirmation, followed by the construction of phylogenetic trees to determine their genetic relations. Various statistical tools were used to analyze related risk factors. There were three species of Anaplasma detected from the Hainan region; namely, A. phagocytophilum, A. bovis, and A. platys. The overall prevalence of Anaplasma is 9.7% (102/1051). A. phagocytopihum was prevalent in 1.0% of dogs (11/1051), A. bovis was found in 2.7% of dogs (28/1051), and A. platys in 6.0% of dogs (63/1051). Our surveillance-based study conducted to understand the occurrence and distribution pattern of Anaplasma spp. in Hainan will help in designing effective control measures along with management strategies so as to treat and control the infection in the area.

Vector-borne disease and its relationship to hematologic abnormalities and microalbuminuria in retired racing and show-bred greyhounds

Background

Reference intervals for platelets and white blood cell (WBCs) counts are lower in greyhounds than other breeds. Proteinuria is common. Vector‐borne diseases (VBD) cause thrombocytopenia, leukopenia, and proteinuria. Racing greyhounds are commonly exposed to vectors that carry multiple organisms capable of chronically infecting clinically healthy dogs.

Hypothesis/Objectives

Vector‐borne disease prevalence is higher in retired racing greyhounds than in show‐bred greyhounds. Occult infection contributes to breed‐related laboratory abnormalities.

Animals

Thirty National Greyhound Association (NGA) retired racing and 28 American Kennel Club (AKC) show‐bred greyhounds.

Methods

Peripheral blood was tested for Anaplasma, Babesia, Bartonella, Ehrlichia, hemotropic Mycoplasma, and Rickettsia species using PCR. Antibodies to Anaplasma, Babesia, Bartonella, Ehrlichia, and Rickettsia species and Borrelia burgdorferi were detected using immunofluorescence and ELISA assays. Complete blood counts, semiquantitative platelet estimates, and microalbuminuria concentration were determined.

Results

Seven of 30 NGA and 1/28 AKC greyhounds tested positive for ≥1 VBD (P = .05). More positive tests were documented in NGA (10/630) than in AKC dogs (1/588; P = .02). Exposure to Bartonella species (3/30), Babesia vogeli (2/30), Ehrlichia canis (1/30), and infection with Mycoplasma hemocanis (3/30) occurred in NGA dogs. Platelet counts or estimates were >170 000/μL. White blood cell counts <4000/μL (4/28 AKC; 5/30 NGA, P > .99; 1/8 VBD positive; 8/51 VBD negative, P = .99) and microalbuminuria (10/21 AKC; 5/26 NGA, P = .06; 1/8 VBD positive; 14/25 VBD negative, P = .41) were not associated with VBD.

Conclusions and Clinical Importance

The prevalence of thrombocytopenia and B. vogeli exposure was lower than previously documented. Larger studies investigating the health impact of multiple VBD organisms are warranted.

A newly developed droplet digital PCR for Ehrlichia canis detection: comparisons to conventional PCR and blood smear techniques

Canine monocytic ehrlichiosis caused by Ehrlichia canis infection is a life-threatening vector-borne disease in dogs worldwide. Routine blood smear has very low sensitivity and cannot accurately provide a quantitative result. Conventional PCR (cPCR) and real-time PCR (qPCR) are widely used as molecular methods for E. canis detection. qPCR is quantitative but relies on standard curves of known samples. To overcome this difficulty, this study developed a new E. canis quantitative detection method, using droplet digital polymerase chain reaction (ddPCR). ddPCR was evaluated against cPCR and blood smears. PCR amplicons and genomic DNA (gDNA) from 12 microscopic positive samples were used to identify the limits of detection (LODs) in ddPCR and cPCR. Our ddPCR was assessed in 92 field samples, it was compared with cPCR and blood smears. ddPCR showed LOD = 1.6 copies/reaction, or 78 times more sensitive than cPCR (LOD = 126 copies/reaction), using PCR amplicons as a template, whereas both ddPCR and cPCR had equal LODs at 0.02 ng gDNA/reaction. In addition, ddPCR had 100% sensitivity and 75% specificity for E. canis detection compared to cPCR and no cross-reaction with other blood pathogens was observed. ddPCR identified more positive samples than cPCR and blood smear. ddPCR improved the overall performance of E. canis detection, with a better LOD and comparable sensitivity and specificity to cPCR. The technique might be helpful for diagnosis of E. canis in light infection, evaluating the number of E. canis and follow-up after treatment.

[Role of systemic infections in canine kidney diseases]

Kidney diseases represent a common problem as well as a frequent cause of death in dogs. Infectious agents may be responsible for glomerulopathies and acute kidney injuries. Many infections commonly associated with the development of immune complex glomerulonephritis in central and southern Europe are important as travel-associated diseases in Germany. These include leishmaniosis, dirofilariosis, and ehrlichiosis. Rarely, anaplasmosis, hepatozoonosis, Lyme disease as well as babesiosis caused by small Babesia spp. are detected as cause of canine immune complex glomerulonephritis in Germany. Leptospirosis, canine infectious hepatitis, and babesiosis caused by large Babesia spp. may be responsible for the development of acute kidney injuries associated with tubulointerstitial nephritis. Therefore, further diagnostics aiming at identifying potentially causative infectious agents in dogs with renal disease is important for both prognosis and therapy of the patient.

Duplex real-time PCR methods for molecular detection and characterization of canine tick-borne haemoparasites from Punjab state, India

Background

Microscopy is a routinely used technique for the diagnosis of canine tick-borne haemoparasitic diseases in various clinical laboratories worldwide. In an attempt to provide better diagnostic assay to the clients for effective management of these diseases duplex real-time PCR assays were applied.

Methods and results

Blood samples (n = 338) aseptically collected from suspected dogs of Central Plain Zone of Punjab state, India were subjected to SYBR Green based real-time duplex PCR assays for simultaneous detection of B. vogeli & E. canis and B. gibsoni & H. canis. Results revealed an overall prevalence rate of canine tick-borne haemoparasites as 54.1%, amongst which H. canis was the predominant (25.4%), followed by B. gibsoni (16.3%), E. canis (10.7%) and B. vogeli (1.8%). Sensitivity and specificity of the duplex assays ranged from 59.04 to 100.0% and 58.12 to 92.52%, respectively and their strength of agreement was ″fair″ with kappa value statistics. A significant (p < 0.05) association between prevalence of B. gibsoni, H. canis and E. canis infection with risk factors like sex, breed, season and location was recorded. The ancestral background of the field isolates of haemoparasites was also studied by phylogenetic analysis of their nucleotide sequences.

Conclusions

SYBR Green dye based duplex real-time PCR assays proved to be highly sensitive, specific, rapid and affordable diagnostic tests for use by clinicians to save the life of pets.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11033-022-07286-4.

Bartonella spp. seroepidemiology and associations with clinicopathologic findings in dogs in the United States

Background

Improved understanding of Bartonella spp. serology in dogs may aid clinical decision making.

Objective

Describe demographic and geographic patterns of Bartonella spp. seroreactivity in dogs, and describe hematologic and serum biochemical abnormalities in Bartonella spp. seroreactive and nonseroreactive dogs.

Animals

Serum samples from 5957 dogs in the United States, previously submitted to IDEXX Reference Laboratories.

Methods

Serum was tested using 3 indirect ELISAs for B. henselae, B. vinsonii subsp. berkhoffii, and B. koehlerae. Complete blood count and serum biochemistry panel results were reviewed retrospectively.

Results

Overall, 6.1% of dogs were Bartonella spp. seroreactive. Toy breeds were less likely to be seroreactive (3.9%) than mixed breeds (7.5%; adjusted odds ratio [aOR], 0.48; 95% confidence interval [CI], 0.32‐0.72), and dogs <1 year old were less likely to be seroreactive (3.4%) than dogs 1 to 5.5 years of age (7.3%; aOR, 0.42; 95% CI, 0.23‐0.72). Dogs in the West South Central (9.8%) and South Atlantic (8.8%) regions were more likely than dogs elsewhere in the United States to be seroreactive (aOR, 2.22; 95% CI, 1.31‐3.87; aOR, 2.44; 95% CI, 1.38‐4.36).

Conclusions and Clinical Importance

Demographic and geographic findings for Bartonella spp. exposure were broadly comparable to previously reported patterns.

Epidemiological and Clinicopathological Features of Anaplasma phagocytophilum Infection in Dogs: A Systematic Review

Anaplasma phagocytophilum is a worldwide emerging zoonotic tick-borne pathogen transmitted by Ixodid ticks and naturally maintained in complex and incompletely assessed enzootic cycles. Several studies have demonstrated an extensive genetic variability with variable host tropisms and pathogenicity. However, the relationship between genetic diversity and modified pathogenicity is not yet understood. Because of their proximity to humans, dogs are potential sentinels for the transmission of vector-borne pathogens. Furthermore, the strong molecular similarity between human and canine isolates of A. phagocytophilum in Europe and the USA and the positive association in the distribution of human and canine cases in the USA emphasizes the epidemiological role of dogs. Anaplasma phagocytophilum infects and survives within neutrophils by disregulating neutrophil functions and evading specific immune responses. Moreover, the complex interaction between the bacterium and the infected host immune system contribute to induce inflammatory injuries. Canine granulocytic anaplasmosis is an acute febrile illness characterized by lethargy, inappetence, weight loss and musculoskeletal pain. Hematological and biochemistry profile modifications associated with this disease are unspecific and include thrombocytopenia, anemia, morulae within neutrophils and increased liver enzymes activity. Coinfections with other tick-borne pathogens (TBPs) may occur, especially with Borrelia burgdorferi, complicating the clinical presentation, diagnosis and response to treatment. Although clinical studies have been published in dogs, it remains unclear if several clinical signs and clinicopathological abnormalities can be related to this infection.

Molecular detection of tick-borne pathogens in infected dogs associated with Rhipicephalus sanguineus tick infestation in Thailand

Background and Aim:

Tick-borne pathogens (TBPs) are of great concern having the potential to threaten canine health. Dogs infected with Ehrlichia canis, Anaplasma platys, Babesia canis, and Hepatozoon canis are commonly found in Thailand; Rhipicephalus sanguineus tick is the most common vector of diseases. This study aimed to determine the prevalence of common TBPs in dogs and their ticks in Thailand using polymerase chain reaction (PCR) and DNA sequencing methods.

Materials and Methods:

Forty-four blood samples were positively diagnosed with TBPs infection by microscopy. Samples were from animal hospitals in Maha Sarakham, Amnat Charoen, Nakhon Ratchasima, and Bangkok, Thailand, during January-June 2020. Five to six ticks were also taken from infected dogs, and then, both blood and tick were analyzed using PCR and DNA sequencing.

Results:

PCR results showed that R. sanguineus was the only tick species detected in this study. The appearance of single infection with E. canis was the most common infection found in dogs and ticks (64% and 82%, respectively). Correlation of pathogen infection in hosts and their vector was performed by similarity detection of pathogens between blood and tick samples based on PCR analysis in 29 samples (66%) but there was no significant differentiation.

Conclusion:

E. canis appears as the most common canine tick-borne pathogen in Thailand, which was detected in both healthy and sick dogs as well as in R. sanguineus. The findings show the relationships among host dogs, pathogens, and ticks. Veterinarians should be proactive in educating pet owners about the risks associated with ticks and their important pathogens and plan effective control strategies.

Molecular epidemiology and prevalence of babesial infections in dogs in two hyperendemic foci in Brazil

Babesial parasites are some of the most ubiquitous blood pathogens and consequently have considerable worldwide veterinary impact. Dogs living in the tropics are highly exposed to babesial parasites, particularly to Babesia vogeli. Limited data on the seroprevalence and molecular prevalence of Babesia spp. in dogs are available in Latin America. We conducted a cross-sectional study combining serological and molecular tests to estimate the seroprevalence and molecular epidemiology of Babesia spp. infections in dogs in two hyperendemic foci in Brazil. A total of 630 privately owned dogs (417 from Goiana municipality, Pernambuco state, north-eastern Brazil, and 213 from São Joaquim de Bicas municipality, Minas Gerais state, south-eastern Brazil) were sampled and molecularly and serologically tested for Babesia spp. Overall, 519 dogs (82.4%) presented detectable IgG antibodies against Babesia spp., and seropositivity was significantly higher in dogs older than 1 year. Molecularly, 34 dogs (5.4%) were positive for a ~ 200 bp fragment of the 18S rRNA gene of Babesia spp. and 88 (14.0%) for a longer fragment (~ 450 bp) of the same gene of Babesia spp. and other protozoa. The 18S rRNA gene sequences generated herein corresponded to B. vogeli (n = 52) or Hepatozoon canis (n = 20). This study confirms a high level of exposure to B. vogeli in two areas of Brazil and highlights that most of the dogs living in these areas are infected during the course of their life, reflected by increased seroprevalence in older dogs. Increased awareness and prevention of tick-borne protozoa infections in dogs from Brazil and Latin America are urgently needed.

First Molecular Detection of Babesia gibsoni in Stray Dogs from Thailand

In southern Thailand, the increasingly growing population of stray dogs is a concern to public health and environmental safety because of the lack of medical attention and control. More importantly, these animals are considered reservoirs for many zoonotic pathogens. The objective of this study was to molecularly detect canine vector-borne pathogens, and to perform genetic characterization of Babesia gibsoni present in stray dogs from southern Thailand. Blood samples were collected from 174 stray dogs in two provinces (Songkhla and Narathiwat) in southern Thailand. PCR analyses were executed using specific primers based on the Babesia spp. 18S rRNA gene, Babesia gibsoni Internal transcribed spacer 1 (ITS1) region, Ehrlichia canis citrate synthase (gltA) gene, Hepatozoon spp. 18S rRNA gene and Anaplasma platys heat shock protein (groEL) gene. The most common canine vector-borne pathogen found infecting stray dogs in this study was Hepatozoon canis (24.7%) followed by A. platys (14.9%), Babesia vogeli (8.0%), B. gibsoni (6.3%), and E. canis (1.72%). Concurrent infection with more than one pathogen occurred in 72 cases. Phylogenetic analysis based on the ITS1 region and 18S rRNA gene revealed that the B. gibsoni isolates from this study shared a large proportion of their identities with each other and with other reported B. gibsoni genotypes from Asia. This study highlights the molecular detection of B. gibsoni in dogs in Thailand for the first time and presents the genetic characterization by sequencing the ITS1 region and 18S rRNA gene of B. gibsoni from Thailand. Follow-up studies are needed to elucidate the origin, distribution, and vectors of B. gibsoni parasites circulating in dogs in Thailand, as well as to determine to what extent dogs are important reservoir hosts for zoonotic canine vector-borne disease infection in the studied area.

Molecular Detection of Tick-Borne Pathogens in Stray Dogs and Rhipicephalussanguineus sensu lato Ticks from Bangkok, Thailand

Canine tick-borne pathogens (CTBPs) such as Babesia vogeli, Ehrlichia canis, Anaplasma platys, Hepatozoon canis, and Mycoplasma haemocanis are important pathogens in dogs worldwide. Rhipicephalus sanguineus sensu lato, the main vector of several CTBPs, is the most common tick species found on dogs in Thailand. The present study identified CTBPs in dogs and ticks infested dogs. Samples (360 dog blood samples and 85 individual ticks) were collected from stray dogs residing in 37 temples from 24 districts in Bangkok and screened for CTBPs using molecular techniques. The most common CTBP found infecting dogs in this study was Ehrlichia canis (38.3%) followed by Mycoplasma haemocanis (34.2%), Hepatozoon canis (19.7%), Babesia vogeli (18.1%), and Anaplasma platys (13.9%), respectively. Furthermore, A. platys (22.4%) was the most common CTBP in ticks followed by M. haemocanis (18.8%), B. vogeli (9.4%), H. canis (5.9%), and E. canis (2.4%), respectively. The detection of CTBPs from the present study highlights the potential risk of infections that may occur in stray dogs and their ticks residing in Bangkok temples. These findings underline the importance of performing active surveys to understand the complexity of distributions of CTBPs in dogs and their ticks in Thailand.

Molecular detection and characterization of Anaplasma platys and Ehrlichia canis in dogs from the Caribbean

Anaplasma platys is a tick-transmitted rickettsial pathogen, which is known to be the etiologic agent for cyclic thrombocytopenia in its primary canine host. Infections with this pathogen are also reported in cats, cattle and people. Similarly, Ehrlichia canis is another tick-borne rickettsial pathogen responsible for canine monocytic ehrlichiosis and is also reported to cause infections in people. We describe infections in dogs with these two pathogens on the Caribbean island of Grenada, West Indies by detection using molecular methods. We utilized a 16S rRNA gene-based PCR assay to detect both Ehrlichia and Anaplasma species by screening 155 canine blood samples from asymptomatic dogs. We found 18.7 % of the dogs to be positive for A. platys and 16.8 % for E. canis. Samples that tested positive for A. platys were further assessed by sequence analysis targeting 16S rRNA, 23S rRNA, citrate synthase (gltA) and heat shock protein (groEL) genes. Phylogenetic analysis revealed high correlation of A. platys 16S rRNA and gltA gene sequences with the geographic origins, while 23S rRNA and groEL gene sequences clustered independent of the geographic origins. This study represents an important step in defining the widespread distribution of active rickettsial infections in Caribbean dogs with no apparent clinical signs, thus posing a high risk for canine health and to a lesser extent to humans, as most dogs in the Caribbean are free-roaming.

Development of a Multiplex PCR and Magnetic DNA Capture Assay for Detecting Six Species Pathogens of the Genera Anaplasma and Ehrlichia in Canine, Bovine, Caprine and Ovine Blood Samples from Grenada, West Indies

Infections with tick-borne pathogens belonging to Anaplasma/Ehrlichia in various vertebrate hosts are a persistent problem resulting in nonspecific clinical signs during early infection. Diagnosis of single and multi-infections with these pathogens, causing diseases in companion/agricultural animals and people, remains a challenge. Traditional methods of diagnosis, such as microscopy and serology, have low sensitivity and specificity. Polymerase chain reaction (PCR) assays are widely used to detect early-phase infections, since these have high sensitivity and specificity. We report the development and validation of an assay involving PCR followed by magnetic capture method using species-specific oligonucleotides to detect six Anaplasma/Ehrlichia species pathogens in canine, bovine, caprine, and ovine blood samples. Overall, the assay application to 455 samples detected 30.1% (137/455) positives for one or more out of six screened pathogens. Single-pathogen infections were observed in 94.9% (130/137) of the positive samples, while co-infections were detected in 5.1% (7/137). Anaplasma marginale infection in cattle had the highest detection rate (34.4%), followed by canines positive for Anaplasma platys (16.4%) and Ehrlichia canis (13.9%). The assay aided in documenting the first molecular evidence for A. marginale in cattle and small ruminants and Ehrlichia chaffeensis and Ehrlichia ewingii in dogs in the Caribbean island of Grenada.

Molecular Prevalence and Identification of Ehrlichia canis and Anaplasma platys from Dogs in Nay Pyi Taw Area, Myanmar

Ticks are vectors of different types of viruses, protozoans, and other microorganisms, which include Gram-negative prokaryotes of the genera Rickettsiales, Ehrlichia, Anaplasma, and Borrelia. Canine monocytic ehrlichiosis caused by Ehrlichia canis and canine cyclic thrombocytopenia caused by Anaplasma platys are of veterinary importance worldwide. In Myanmar, there is limited information concerning tick-borne pathogens, Ehrlichia and Anaplasma spp., as well as genetic characterization of these species. We performed nested PCR for the gltA gene of the genus Ehrlichia spp. and the 16S rRNA gene of the genus Anaplasma spp. with blood samples from 400 apparently healthy dogs in Nay Pyi Taw area. These amplicon sequences were compared with other sequences from GenBank. Among the 400 blood samples from dogs, 3 (0.75%) were positive for E. canis and 1 (0.25%) was positive for A. platys. The partial sequences of the E. canis gltA and A. platys 16SrRNA genes obtained were highly similar to E. canis and A. platys isolated from different other countries.

Cytokine profile and parasite load in lymph nodes of dogs naturally infected with Leishmania infantum from distinct epidemiological scenarios in São Paulo State, Brazil

Visceral leishmaniasis (VL) is an important zoonotic vector-borne disease and domestic dogs are considered the main domiciliary and peri-domiciliary reservoir of Leishmania (Leishmania) infantum in South America. Distinct eco-epidemiological scenarios associated to the prevalence of the disease, clusters of parasite genotypes and chemotypes of vectors population are described in Brazil, especially in the state of São Paulo (SP). In this context, the purpose of the present study is to evaluate the clinical signs, histopathological lesions, parasite load and cytokine profile by immunohistochemistry (IHC) in popliteal lymph nodes of canines naturally infected with L. infantum, from different municipalities of the state of SP. Eighty-three dogs with VL, 61 from northwest SP (NWSP) and 22 from southeast SP (SESP), were clinically classified in stage II, with no babesiosis and ehrlichiosis. Subcapsular inflammatory infiltration and histiocytosis were significantly higher in the SESP group (p = 0.0128; 0.0077, respectively). On the other hand, dogs from NWSP revealed 4.6-fold significantly higher parasite burden (p = 0.0004) and higher IHC scores of IL-1β (p = 0.0275) and IL-4 (p = 0.0327) in the popliteal lymph node tissues, which may be associated with the susceptibility and progression of the disease in these dogs. Differences in immune response profile associated with higher parasite load in dogs can also contribute to explain the distinct eco-epidemiological patterns of VL in specific geographic regions.

Ticks and Tick-Borne Diseases of Livestock in the Middle East and North Africa: A Review

Ticks are important vectors of an array of viral, bacterial and protozoan pathogens resulting in a wide range of animal and human diseases. There is limited information in the literature about tick species in the Middle East and North Africa (MENA) countries, even though they have suitable climate and vegetation for ticks and their hosts. We reviewed the occurrence of tick species and the pathogens they transmit from the MENA on published papers from 1901-2020. We found taxonomic records of 55 tick species infesting livestock representing the following eight genera: Ornithodoros, Otobius, Amblyomma, Dermacentor, Haemaphysalis, Hyalomma, Ixodes, and Rhipicephalus. In addition, 15 pathogens were recorded causing diseases of significance, with Crimean-Congo hemorrhagic fever, theileriosis, babesiosis and anaplasmosis being widely distributed diseases in the region. In recent decades, there has been increasing trends in disease occurrence and movement associated with global movement of humans and global trade of animals. We suggest that disease control and prevention could be achieved effectively through good integration between public health, veterinary medicine and animal management, and ecological approaches. We recommend further research in the areas of tick ecology and tick born-disease transmission. Furthermore, we suggest evaluation and improvement of disease control policies in the region.

Comparison of Anaplasma and Ehrlichia species-specific peptide ELISAs with whole organism-based immunofluorescent assays for serologic diagnosis of anaplasmosis and ehrlichiosis in dogs

OBJECTIVE

To compare the performance of 5 synthetic peptide-based ELISAs with that of 3 commercially available immunofluorescent assays (IFAs) for serologic diagnosis of anaplasmosis and ehrlichiosis in dogs.

SAMPLE

A convenience set of 109 serum samples obtained before and at various times after inoculation for 23 dogs that were experimentally infected with Anaplasma phagocytophilum, Anaplasma platys, Ehrlichia canis, Ehrlichia chaffeensis, or Ehrlichia ewingii and 1 uninfected control dog in previous studies.

PROCEDURES

All serum samples were assessed with 5 synthetic peptide-based ELISAs designed to detect antibodies against A phagocytophilum, A platys, E canis, E chaffeensis, and E ewingii and 3 whole organism-based IFAs designed to detect antibodies against A phagocytophilum, E canis, and E chaffeensis. The species-specific seroreactivity, cross-reactivity with the other tick-borne pathogens (TBPs), and diagnostic sensitivity and specificity were calculated for each assay and compared among assays.

RESULTS

All serum samples obtained from dogs experimentally infected with a TBP yielded positive results on a serologic assay specific for that pathogen. In general, sensitivity was comparable between ELISAs and IFAs and tended to increase with duration after inoculation. Compared with the IFAs, the corresponding ELISAs were highly specific and rarely cross-reacted with antibodies against other TBPs.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that peptide-based ELISAs had enhanced specificity relative to whole organism-based IFAs for detection of antibodies against Anaplasma and Ehrlichia spp, which should facilitate accurate diagnosis and may help detect dogs coinfected with multiple TBPs.

Serological prevalence of six vector-borne pathogens in dogs presented for elective ovariohysterectomy or castration in the South central region of Texas

Background

Most vector-borne pathogens cause zoonotic diseases. These zoonoses often have wild animal reservoirs that play a significant role in disease epidemiology. However, pet animals have also been implicated in transmission of zoonotic agents to humans. To exemplify, dogs are competent reservoir hosts for several zoonotic vector-borne bacteria and protozoa. Despite that vector-borne diseases can be life-threatening for both pets and humans, studies on pathogen seroprevalence are very limited. Therefore, the objective of this study was to determine the serological prevalence of six zoonotic vector-borne agents in dogs from the South Central region of Texas (US).

Electronic medical records of dogs, presenting over 2014–2019 for elective ovariohysterectomy or castration at a high volume spay and neuter clinic, were reviewed for serological testing. Sera from 418 dogs were tested for the Dirofilaria immitis antigen, and antibodies to Anaplasma phagocytophilum, Anaplasma platys, Borrelia burgdorferi, Ehrlichia canis, and Ehrlichia ewingi, using a commonly available commercial test kit. Descriptive statistics were computed to characterize the respective seroprevalence rates of the dog population. The study involved 192 (46%) male and 226 (54%) female dogs.

Results

Overall, 85 (20%) dogs tested positive for at least one of the 6 pathogens investigated. The highest seroprevalence rate averaged over the 6-year period was 11.7% for D. immitis followed by 8.4% for E. canis and/or E. ewingii, 4.3% for A. phagocytophilum and/or A. platys, and 0.2% for B. burgdorferi. The co-exposure or co-infection was only detected in 3.8% of the dog population.

Conclusions

Together, opportunistic testing of dogs presenting for elective surgical procedures may provide an effective way of assessing seroprevalence and/or risk factors for common vector-borne diseases within a geographic region of concern.

Detection of tick-borne rickettsial pathogens in naturally infected dogs and dog-associated ticks in Medellin, Colombia

Tick-borne rickettsial pathogens (TBRP) are important causes of infections in both dogs and humans. Dogs play an important role as a biological host for several tick species and can serve as sentinels for rickettsial infections. Our aim was to determine the presence of TBRP in dogs and in dog-associated ticks and their potential risk to human diseases in Medellin, Colombia. DNA for E. canis (16S rRNA and dsb) and A. platys (groEl) was detected in 17.6% (53/300) and 2.6% (8/300) of dogs, respectively. Antibodies against Ehrlichia spp. 82 (27.3%) and Anaplasma spp. 8 (2.6%) were detected in dogs. Antibody reactivity against both agents were found in 16 dogs (5.3%). Eight dogs showed antibody for Rickettsia spp. with titers that suggest 3 of them had a probable exposure to R. parkeri. Rhipicephalus sanguineus s.l. (178/193) was the main tick in dogs, followed by R. microplus (15/193). The minimum infection rates (MIR) in R. sanguineus were 11.8% for E. canis and 3.4% for A. platys. E. canis and A. platys are the main TBRP infecting dogs and ticks and R. sanguineus s.l. is likely involved in the transmission of both agents. Interestingly, we found serological evidence of exposure in dogs for spotted fever group rickettsiae.

Prevalence and incidence of vector-borne pathogens in unprotected dogs in two Brazilian regions

Background

Various vector-borne pathogens (VBPs) affect dogs worldwide, with their diversity and force of infection being usually higher in the tropics. Cross-sectional studies have been conducted to investigate the prevalence of VBPs in dogs, but data from longitudinal studies are scarce. Herein, we assessed the prevalence and the year-crude incidence (YCI) of Leishmania spp. and other VBPs in privately-owned dogs from two geographical regions of Brazil.

Methods

A total of 823 dogs were initially screened for Leishmania spp. by both serology and polymerase chain reaction (PCR). From the negatives, 307 (103 from São Joaquim de Bicas, Minas Gerais, and 204 from Goiana, Pernambuco) were randomly selected for the longitudinal study. These dogs were tested for various VBPs at baseline, after 8 and 12 months.

Results

Out of 823 dogs initially screened, 131 (15.9%) were positive for Leishmania spp. Out of the 307 dogs enrolled in the longitudinal study, 120 (39.1%) were lost for different reasons (e.g. animal death, owner decision, and lost to follow-up). In São Joaquim de Bicas, the baseline prevalence and YCI were as follows: 16.5% and 7.1% for Anaplasma spp.; 81.6% and 100% for Babesia spp.; 0% and 1.3% (only one faint positive) for Dirofilaria immitis; 37.9% and 22.9% for Ehrlichia spp.; 19.5% and 43.8% for Leishmania spp. In Goiana, the baseline prevalence and YCI were as follows: 45.1% and 38.3% for Anaplasma spp.; 79.9% and 96.0% for Babesia spp.; 36.3% and 39.8% for D. immitis; 64.7% and 58.5% for Ehrlichia spp.; 14.7% and 19.6% for Leishmania spp. Anti-Borrelia burgdorferi antibodies were not detected in any of the samples tested herein. The prevalence and YCI of Anaplasma spp., D. immitis and Ehrlichia spp. were significantly higher in Goiana. In contrast, the YCI of Leishmania spp. infection was significantly higher in São Joaquim de Bicas.

Conclusions

We confirmed a high prevalence and YCI of various VBPs among privately-owned dogs in two geographical regions of Brazil. Our data also indicate that the risk of infection varies significantly for individual VBPs and between the regions, which may be related to several factors that are still poorly understood.

A retrospective study of vector-borne disease prevalence in dogs with proteinuria: Southeastern United States

Background

Proteinuria is a risk factor for progressive kidney injury in dogs. Enhanced understanding of potential associations between canine vector‐borne diseases (CVBD) and proteinuria is needed.

Objectives

To determine the proportion of evaluated proteinuric dogs exposed to ≥1 CVBD, including Babesia spp., Ehrlichia spp., spotted‐fever group Rickettsia, Bartonella spp., Anaplasma spp., hemotropic Mycoplasma spp., Borrelia burgdorferi, and Dirofilaria immitis, and to determine if demographic or clinicopathologic differences exist between proteinuric dogs exposed to CVBD versus proteinuric dogs with no evidence of CVBD exposure.

Animals

Two‐hundred nine proteinuric dogs, concurrently tested for CVBD, which were examined at a single academic veterinary hospital between January 2008 and December 2015.

Methods

Retrospective cross‐sectional study. Demographic, clinicopathologic, and CVBD test results were extracted from medical records. A multivariable logistic regression model was used to assess associations between CVBD and selected variables.

Results

Based on serology and polymerase chain reaction testing, 34% of proteinuric dogs (72/209) were exposed to ≥1 CVBD. Exposure to Rickettsia spp. (19%), Ehrlichia spp. (12%), and B. burgdorferi (9%) were most common. The CVBD exposure was lower in dogs tested in autumn or spring, higher in intact dogs, and higher in dogs with lower serum albumin and higher serum creatinine concentrations.

Conclusions and Clinical Importance

Exposure to CVBD, particularly exposure to Rickettsia spp., Ehrlichia spp., and B. burgdorferi was found in proteinuric dogs from the southeast United States. Additional controlled prospective studies examining a potential causal relationship between CVBD and proteinuria are warranted.

Detection of Bartonella spp. in dogs after infection with Rickettsia rickettsii

Background

Dynamics of infection by Bartonella and Rickettsia species, which are epidemiologically associated in dogs, have not been explored in a controlled setting.

Objectives

Describe an outbreak investigation of occult Bartonella spp. infection among a group of dogs, discovered after experimentally induced Rickettsia rickettsii (Rr) infection.

Animals

Six apparently healthy purpose‐bred Beagles obtained from a commercial vendor.

Methods

Retrospective and prospective study. Dogs were serially tested for Bartonella spp. and Rr using serology, culture, and PCR, over 3 study phases: 3 months before inoculation with Rr (retrospective), 6 weeks after inoculation with Rr (retrospective), and 8 months of follow‐up (prospective).

Results

Before Rr infection, 1 dog was Bartonella henselae (Bh) immunofluorescent antibody assay (IFA) seroreactive and 1 was Rickettsia spp. IFA seroreactive. After inoculation with Rr, all dogs developed mild Rocky Mountain spotted fever compatible with low‐dose Rr infection, seroconverted to Rickettsia spp. within 4‐11 days, and recovered within 1 week. When 1 dog developed ear tip vasculitis with intra‐lesional Bh, an investigation of Bartonella spp. infection was undertaken. All dogs had seroconverted to 1‐3 Bartonella spp. between 7 and 18 days after Rr inoculation. Between 4 and 8 months after Rr inoculation, Bh DNA was amplified from multiple tissues from 2 dogs, and Bartonella vinsonii subsp. berkhoffii (Bvb) DNA was amplified from 4 of 5 dogs' oral swabs.

Conclusions and Clinical Importance

Vector‐borne disease exposure was demonstrated in research dogs from a commercial vendor. Despite limitations, our results support the possibilities of recrudescence of chronic subclinical Bartonella spp. infection after Rr infection and horizontal direct‐contact transmission between dogs.

Seroprevalence of Canine Ehrlichiosis and Microscopic Screening for Canine Babesiosis in Dogs in Harare, Zimbabwe, 2016-2017

A cross-sectional study was done to determine ehrlichiosis seroprevalence and babesiosis prevalence in dogs that were presented to selected veterinary clinics in Harare. Sera from randomly selected dogs were tested for antibodies to Ehrlichia spp. using an enzyme-linked immunosorbent assay while microscopy of peripheral blood smears was used to confirm babesiosis. Overall, 75.2% (88/117, 95% CI: 66.2–82.5) of sera samples tested were positive to Ehrlichia spp. antibodies while the prevalence of canine babesiosis was 47.9% (56/117, 95% CI: 38.6–57.3). Age, breed, and sex were found not to be associated with the two disease conditions (p > 0.05). Most of the dogs with babesiosis (82.1%, 46/56) were also positive to Ehrlichia spp. antibodies. Hypoalbuminaemia (53.8%, 63/117), anaemia (53.0%, 62/117) and thrombocytopaenia (40.2%, 47/117) were the most common laboratory findings. Thrombocytopaenia and hypoalbuminaemia was more pronounced in dogs with babesiosis only while anaemia was more marked in dogs with babesiosis and positive to Ehrlichia spp. antibodies.

Canine vector-borne disease: mapping and the accuracy of forecasting using big data from the veterinary community

Diagnosis, treatment, and prevention of vector-borne disease (VBD) in pets is one cornerstone of companion animal practices. Veterinarians are facing new challenges associated with the emergence, reemergence, and rising incidence of VBD, including heartworm disease, Lyme disease, anaplasmosis, and ehrlichiosis. Increases in the observed prevalence of these diseases have been attributed to a multitude of factors, including diagnostic tests with improved sensitivity, expanded annual testing practices, climatologic and ecological changes enhancing vector survival and expansion, emergence or recognition of novel pathogens, and increased movement of pets as travel companions. Veterinarians have the additional responsibility of providing information about zoonotic pathogen transmission from pets, especially to vulnerable human populations: the immunocompromised, children, and the elderly. Hindering efforts to protect pets and people is the dynamic and ever-changing nature of VBD prevalence and distribution. To address this deficit in understanding, the Companion Animal Parasite Council (CAPC) began efforts to annually forecast VBD prevalence in 2011. These forecasts provide veterinarians and pet owners with expected disease prevalence in advance of potential changes. This review summarizes the fidelity of VBD forecasts and illustrates the practical use of CAPC pathogen prevalence maps and forecast data in the practice of veterinary medicine and client education.

Ecological and Socioeconomic Factors Associated with Bartonella henselae Exposure in Dogs Tested for Vector-Borne Diseases in North Carolina

Bartonella henselae is a zoonotic vector-borne pathogen affecting both humans and dogs. Little is known about the epidemiology of B. henselae in dogs, including risk factors associated with exposure. The objectives of this study were to map the current distribution of B. henselae in dogs in North Carolina (NC) and to identify ecological and socioeconomic factors influencing B. henselae seroreactivity. Results from 4446 B. henselae serology samples from dogs in NC submitted by veterinarians for clinical diagnostic testing to the North Carolina State University College of Veterinary Medicine Vector Borne Disease Diagnostic Laboratory between January 1, 2004 and December 31, 2015 were retrospectively reviewed. These results were used to generate a map of B. henselae seroreactivity. To account for sparsely sampled areas, statistical smoothing using head banging and areal interpolation kriging was performed. Using previously described risk factors for exposure to canine tick-borne diseases, eight multivariable logistic regression models based on biologically plausible hypotheses were tested, and a final model was selected using an Akaike's Information Criterion weighted-average approach. Seroreactivity among dogs tested for vector-borne disease was variable across the state: higher along the southern/eastern coastal plains and eastern Piedmont, and lower in the western mountains. Of 25 explanatory factors considered, the model combining demographic, socioeconomic, climatic, and land use variables fits best. Based on this model, female intact sex and increasing percentage of the county with low-intensity development and evergreen forest were associated with higher seroreactivity. Conversely, moderate development, increasing median household income, and higher temperature range and relative humidity were associated with lower seroreactivity. This model could be improved, however, by including local and host-scale factors that may play a significant role in dogs' exposure.

Prevalence of Babesia spp. and clinical characteristics of Babesia vulpes infections in North American dogs

Background

Babesiosis is an important cause of thrombocytopenia and hemolytic anemia in dogs. Babesia vulpes, reported in European dogs and North American foxes, rarely has been reported in domestic North American dogs. Newly optimized polymerase chain reaction (PCR) primers facilitate more sensitive amplification of B. vulpes DNA.

Objectives

To determine the prevalence of Babesia sp. infections in dogs being tested for Babesia infection, and to describe co‐infections and clinicopathologic abnormalities in B. vulpes positive dogs.

Animals

Dog blood or tissue samples (n = 9367) submitted to a diagnostic laboratory between June 2015 and June 2018 were tested using an optimized Babesia PCR assay.

Methods

Comprehensive canine vector‐borne disease diagnostic testing was performed on convenience samples.

Results

Babesia sp. DNA was amplified from 269/9367 (2.9%) North American dogs. Babesia sp. infections included B. gibsoni monoinfection (157; 1.7%), B. vulpes monoinfection (19; 0.20%), and B. gibsoni and B. vulpes coinfection (29; 0.31%). Forty‐three of the 48 total B. vulpes‐infected dogs were American Pit Bull Terrier‐type breeds, of which 36 historically were involved with dog fights. Coinfections with Mycoplasma, Dirofilaria immitis, or Wolbachia and coexposures to Bartonella, Ehrlichia, and Rickettsia spp. were documented in B. vulpes‐infected dogs. Clinicopathologic data in B. vulpes‐infected dogs both with and without coinfections included anemia, thrombocytopenia, hyperglobulinemia, hypoalbuminemia, and proteinuria.

Conclusions and Clinical Importance

Babesia vulpes infection in domestic North American dogs is commonly found in conjunction with other coinfections, including B. gibsoni and hemotropic Mycoplasma. Similar to B. gibsoni, dog‐to‐dog transmission of B. vulpes may be a frequent mode of transmission.

Comparison of conventional polymerase chain reaction and routine blood smear for the detection of Babesia canis, Hepatozoon canis, Ehrlichia canis, and Anaplasma platys in Buriram Province, Thailand

Background and Aim:

Dog blood parasites are important tick-borne diseases causing morbidity and mortality in dogs worldwide. Four dog blood parasites species are commonly found in Thailand: Babesia canis, Hepatozoon canis, Ehrlichia canis, and Anaplasma platys. They are transmitted easily by tick species. However, there is little prevalence data available in Thailand. Diseases presentation of blood parasites infection is similar, but the treatment of each species is different. Current diagnosis mainly relies on microscopic examination of a stained blood smear, which has low sensitivity. Therefore, accurate diagnosis is important. This study aims to evaluate the efficacy of the conventional polymerase chain reaction (PCR) method and routine blood smears in the detection of four blood parasites species in dogs from Buriram Province, Thailand.

Materials and Methods:

In total, 49 EDTA-blood samples were collected from dogs in Buriram Province, Thailand. Blood parasite infection was compared using the Giemsa-stained blood smear technique to identify the parasite under a 100× oil immersion with PCR amplification of the 18S rDNA gene of B. canis and H. canis and the 16S rDNA gene of E. canis and A. platys.

Results:

Only one dog out of 49 was positive for H. canis based on microscopic examination whereas the PCR results showed that 2.04% (1/49), 4.08% (2/49), 36.73% (18/49), and 30.61% (15/49) of dogs were positive for B. canis, H. canis, E. canis, and A. platys, respectively. Moreover, coinfection was found in 16.33% (8/49) of dogs.

Conclusion:

This study is the first report to demonstrate the molecular prevalence of blood parasites in domestic dogs in Buriram Province. The results indicated that the PCR method exhibited much higher sensitivity and reliability for blood parasites diagnosis in dogs. Therefore, our data support serious concern regarding the diagnostic technique used in routine blood testing and also provide prevalence data for the management and control of blood parasites in this area.

Optimal Vector-borne Disease Screening in Dogs Using Both Serology-based and Polymerase Chain Reaction-based Diagnostic Panels

Vector-borne disease and idiopathic immune-mediated disease present similarly. Diagnostic panels that include multiple organisms help detect infection and identify coinfections. Comprehensive diagnostic panels that combine polymerase chain reaction (PCR) and serology should be used in initial screening to maximize sensitivity and identify infection. Repeat testing using PCR is warranted in dogs at high risk of infection with organisms that circulate in blood in low numbers or intermittently. Convalescent serologic testing can help diagnose acute infection. This article discusses the pathophysiology and epidemiology of the organisms, panel selection, and how to recognize when more aggressive testing for an organism is warranted.

Molecular evidence of Ehrlichia canis and Anaplasma platys and the association of infections with hematological responses in naturally infected dogs in Kalasin, Thailand

Background

Tick-borne bacteria, Anaplasma platys and Ehrlichia canis are well recognized as the etiology of anemia and thrombocytopenia in dogs. The clinical signs of anaplasmosis and ehrlichiosis range from asymptomatic to severe symptoms . There are insufficient studies about epidemiological surveys of these blood parasites, also the association of infections with the hematological study.

Aim

This study aimed to screen A. platys and E. canis in naturally infected dogs and the effects of the infection on the levels of packed cell volume (PCV) and platelet count.

Materials and Methods

A total of 68 blood samples were collected from free-roaming dogs at Nong Kung Sri district, Kalasin Province, Thailand, and examined for A. platys and E. canis infection by polymerase chain reaction (PCR) and measured PCV levels and platelet count.

Results

Using nested PCR, 42.65% of dogs were infected with one or two pathogens. The molecular detection of anaplasmosis and ehrlichiosis in this population was 29.4% (95% confidence interval [CI]: 18.98-41.71) and 25% (95% CI: 14.4-35.3), respectively. Coinfection occurred at 11.8% (95% CI: 5.22-21.87). Infection with E. canis and coinfection showed significant association with PCV levels (p<0.05) while A. platys infection showed no statistical relationship. Infection with A. platys, E. canis, and coinfection had a non-significant correlation with platelet count (p>0.05).

Conclusion

This study provides data of anaplasmosis and ehrlichiosis in free-roaming dogs which indicated that these zoonotic diseases are widespread and require for disease frequency determination, especially in Kalasin Province of Thailand where data of tick-borne infections in dogs have not been reported.

Combination of microbiome analysis and serodiagnostics to assess the risk of pathogen transmission by ticks to humans and animals in central Germany

BACKGROUND

Arthropod-borne diseases remain a major health-threat for humans and animals worldwide. To estimate the distribution of pathogenic agents and especially Bartonella spp., we conducted tick microbiome analysis and determination of the infection status of wild animals, pets and pet owners in the state of Hesse, Germany.

RESULTS

In total, 189 engorged ticks collected from 163 animals were tested. Selected ticks were analyzed by next generation sequencing (NGS) and confirmatory PCRs, blood specimens of 48 wild animals were analyzed by PCR to confirm pathogen presence and sera of 54 dogs, one cat and 11 dog owners were analyzed by serology. Bartonella spp. were detected in 9.5% of all ticks and in the blood of 17 roe deer. Further data reveal the presence of the human and animal pathogenic species of genera in the family Spirochaetaceae (including Borrelia miyamotoi and Borrelia garinii), Bartonella spp. (mainly Bartonella schoenbuchensis), Rickettsia helvetica, Francisella tularensis and Anaplasma phagocytophilum in ticks. Co-infections with species of several genera were detected in nine ticks. One dog and five dog owners were seropositive for anti-Bartonella henselae-antibodies and one dog had antibodies against Rickettsia conorii.

CONCLUSIONS

This study provides a snapshot of pathogens circulating in ticks in central Germany. A broad range of tick-borne pathogens are present in ticks, and especially in wild animals, with possible implications for animal and human health. However, a low incidence of Bartonella spp., especially Bartonella henselae, was detected. The high number of various detected pathogens suggests that ticks might serve as an excellent sentinel to detect and monitor zoonotic human pathogens.

Low genetic diversity of Ehrlichia canis associated with high co-infection rates in Rhipicephalus sanguineus (s.l.)

BACKGROUND

Rhipicephalus sanguineus sensu lato (s.l.) is the most widely distributed ixodid tick and is a vector of major canine and human pathogens. High-throughput technologies have revealed that individual ticks carry a high diversity of pathogens, including bacteria, protozoa and viruses. Currently, it is accepted that co-infections (multiple pathogen species within an individual) are very common in ticks and influence pathogen acquisition and transmission as well as host infection risk. However, little is known on the impact of the genetic diversity of pathogens on the incidence of co-infections. Herein, we studied the frequency of co-infections in R. sanguineus (s.l.) and their association with the genetic diversity of Ehrlichia canis.

METHODS

Rhipicephalus sanguineus (s.l.) female ticks (n = 235) were collected from healthy farm dogs in three districts of Pakistan. Microfluidic real-time PCR, a powerful nanotechnology for high-throughput molecular detection of pathogens, was used to test the presence of 25 bacterial and seven parasitic species in individual ticks. The genetic diversity of E. canis was evaluated by characterizing the trp36 gene.

RESULTS

A total of 204 ticks were infected with at least one pathogen and 109 co-infected with two (80%) or three (20%) pathogens. Rickettsia massiliae (human pathogen) and E. canis (zoonotic dog pathogen) were the most common pathogens co-infecting (30.4%) ticks. Furthermore, all identified co-infections included R. massiliae and/or E. canis. Multiple correspondence analysis (MCA) revealed that single infections did not show clear regional association whereas some co-infections were restricted to certain geographical regions. The sequence analysis of trp36 in representative samples allowed the identification of three E. canis strains with low genetic diversity, and the strain found in Muzaffargarh district appeared to be more adapted to co-infection with R. massiliae.

CONCLUSIONS

Rhipicephalus sanguineus (s.l.) harbors multiple co-infections with human and dog pathogens of zoonotic potential. Findings of this study suggest that genetic diversity of E. canis may favor co-infections with different pathogens.

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.

Molecular detection of tick-borne pathogens in canine population and Rhipicephalus sanguineus (sensu lato) ticks from southern Metro Manila and Laguna, Philippines

Background

The tropical climate of the Philippines and the high population of dogs, particularly in cities, favors the life-cycle of the brown dog tick, Rhipicephalus sanguineus (sensu lato), a vector of several canine tick-borne pathogens (TBPs) including zoonotic Rickettsia spp. Suspected cases of infections are commonly encountered in veterinary clinics, but the specific TBPs are rarely identified. Furthermore, infection with Rickettsia is not being clinically examined in dogs. In this study, the occurrence of TBPs in blood and ticks collected from household and impounded dogs in highly populated areas of the Philippines, Metro Manila, and the nearby province of Laguna, was examined.

Results

A total of 248 blood samples and 157 tick samples were subjected to PCR. First, samples were screened using primers for Anaplasma/Ehrlichia spp. and Babesia/Hepatozoon spp. Those that turned positive were further subjected to species-specific PCR. Rickettsia spp. were also detected through a nested PCR. Of the 248 blood samples, 56 (22.6%) were positive for Anaplasma/Ehrlichia spp., while 19 (7.6%) were positive for Babesia/Hepatozoon spp. Species-specific PCR revealed that 61 (23.4%) had a single TBP, with Ehrlichia canis being detected in 39 (15.7%) dogs, while 14 (5.6%) dogs were positive for different combinations of two to four TBPs. Rickettsia infection was detected in 6 (2.4%) dogs. In tick samples, 8 (3.2%) were positive for Ehrlichia/Anaplasma spp., while only 1 (0.63%) was positive for Babesia/Hepatozoon spp. As in the blood samples, E. canis was the most detected, being found in 5 (2%) samples. No tick samples tested positive for Rickettsia spp.

Conclusion

Ehrlichia canis is the most common TBP affecting dogs in the Philippines. Co-infection with TBPs is quite common, hence testing for multiple TBPs is necessary. Through nested PCR, Rickettsia infection was detected in dogs, and to the authors’ knowledge, this study provides the first molecular evidence of Rickettsia infection in dogs in the Philippines.

Detection of Anaplasmataceae agents and co-infection with other tick-borne protozoa in dogs and Rhipicephalus sanguineus sensu lato ticks

Anaplasmosis and ehrlichiosis are of serious health concern worldwide for animals and humans. In the present study, we report the occurrence of Anaplasma platys and Ehrlichia canis in dogs and Rhipicephalus sanguineus sensu lato (s.l.) ticks from Peninsular Malaysia using a nested polymerase chain reaction assay based on amplification of the 16S rRNA gene. Anaplasma platys was detected from dogs and ticks with prevalence rates of 3.3% (8/240) and 2.9% (4/140), respectively. On the other hand, 12.9% (31/240) of the dogs and 0.7% (1/140) of the ticks were tested positive for E. canis. Additionally, co-infections of A. platys and E. canis with Babesia or Hepatozoon protozoa were also noted in this study. Double infection (E. canis + B. gibsoni) was observed in tick, whereas triple infections (E. canis + A. platys + B. vogeli and E. canis + A. platys + H. canis) were found in dogs. This study represents the first evidence of A. platys DNA in R. sanguineus s.l. in Malaysia.

Detection of Ehrlichia, Anaplasma, and Babesia spp. in dogs of Cebu, Philippines

Background

Ehrlichia, Anaplasma, and Babesia spp. are canine pathogens transmitted by the Rhipicephalus sanguineus tick which can cause varied clinical signs. These pathogens have been investigated in the Philippines, but coinfection has not been reported yet.

Aim

The aim of this study was to evaluate the presence of Ehrlichia/Anaplasma and Babesia spp. in Philippine dogs.

Materials and Methods

A total of 100 dogs from seven different veterinary establishments in Cebu, Philippines, were examined for Ehrlichia/Anaplasma and Babesia spp. infection using peripheral blood smear examination and polymerase chain reaction (PCR). Inclusion criteria included a history or presence of tick infestation, anemia, and/or thrombocytopenia. Clinical signs were recorded. Statistical analyses were performed between PCR positivity and clinical signs and hematological results.

Results

A total of 10 and 18 dogs were found to be positive for Ehrlichia/Anaplasma and Babesia spp., respectively. One animal was PCR positive for both pathogens, which is the first report of coinfection in the country. The most common clinical signs observed include inappetence (89%), lethargy (80%), thrombocytopenia (85%), and anemia (74%). Analyses revealed that inappetence (p=0.044) and weight loss (p=0.028) were found statistically significant with Ehrlichia/Anaplasma infection. Basophil (p=0.001) and eosinophil counts (p=0.000) were also found significantly different between Ehrlichia/Anaplasma spp.-positive and -negative dogs. On the other hand, differential monocyte count (p=0.009) was found significantly different between Babesia spp.-positive and -negative dogs.

Conclusion

The present study showed low infection rates of canine ehrlichiosis/anaplasmosis and babesiosis and provided additional evidence for the presence of the pathogens in the area.

Bartonella Seroepidemiology in Dogs from North America, 2008-2014

BACKGROUND

Improved understanding of Bartonella species seroepidemiology in dogs may aid clinical decision making and enhance current understanding of naturally occurring arthropod vector transmission of this pathogen.

OBJECTIVES

To identify demographic groups in which Bartonella exposure may be more likely, describe spatiotemporal variations in Bartonella seroreactivity, and examine co-exposures to other canine vector-borne diseases (CVBD).

ANIMALS

A total of 15,451 serology specimens from dogs in North America were submitted to the North Carolina State University, College of Veterinary Medicine Vector Borne Disease Diagnostic Laboratory between January 1, 2008, and December 31, 2014.

METHODS

Bartonella henselae, Bartonella koehlerae, and Bartonella vinsonii subspecies berkhoffii indirect fluorescent antibody (IFA) serology results, as well as results from a commercial assay kit screening for Dirofilaria immitis antigen and Ehrlichia species, Anaplasma phagocytophilum, and Borrelia burgdorferi antibodies, and Ehrlichia canis, Babesia canis, Babesia gibsoni, and Rickettsia species IFA results were reviewed retrospectively.

RESULTS

Overall, 3.26% of dogs were Bartonella spp. seroreactive; B. henselae (2.13%) and B. koehlerae (2.39%) were detected more frequently than B. vinsonii subsp. berkhoffii (1.42%, P < 0.0001). Intact males had higher seroreactivity (5.04%) than neutered males (2.87%, P < 0.0001) or intact or spayed females (3.22%, P = 0.0003). Mixed breed dogs had higher seroreactivity (4.45%) than purebred dogs (3.02%, P = 0.0002). There was no trend in seasonal seroreactivity; geographic patterns supported broad distribution of exposure, and co-exposure with other CVBD was common.

CONCLUSIONS AND CLINICAL IMPORTANCE

Bartonella spp. exposure was documented throughout North America and at any time of year. Male intact dogs, mixed breed dogs, and dogs exposed to other CVBD have higher seroreactivity to multiple Bartonella species.

Borrelia miyamotoi, Other Vector-Borne Agents in Cat Blood and Ticks in Eastern Maryland

We collected blood and tick samples in eastern Maryland to quantify vector-borne pathogen exposure and infection in healthy cats and to assess occupational disease risk to veterinary professionals and others who regularly interact with household pets. Thirty-six percent of healthy cats parasitized by ticks at time of examination (9/25) were exposed to, and 14% of bloods (7/49) tested PCR-positive for, at least one vector-borne pathogen including several bloods and ticks with Borrelia miyamotoi, a recently recognized tick-borne zoonotic bacterium. There was no indication that high tick burdens were associated with exposure to vector-borne pathogens. Our results underscore the potential importance of cats to human vector-borne disease risk.

A PCR survey of vector-borne pathogens in different dog populations from Turkey

In the present study, a total of 192 blood samples were collected from pet dogs, kennel dogs and shepherd dogs in Konya district, Turkey, and tested by specific PCR for the presence of vector-borne pathogens. Several pathogens were identified, most of which can cause substantial morbidity in dogs. PCR results revealed that 54 (28.1%) dogs were infected with one or more pathogens. Positive results were obtained for Babesia spp. in 4 dogs (2.1%), Hepatozoon spp. in 8 dogs (4.2%) and Mycoplasma spp. in 46 dogs (24%). Three dogs (1.6%) were infected with two or three pathogens. The sequence analysis of the positive DNA samples revealed the presence of Babesia canis vogeli, Hepatozoon canis, Hepatozoon sp. MF, Mycoplasma haemocanis and Candidatus Mycoplasma haematoparvum. Ehrlichia canis and Anaplasma platys were not detected. Regardless of ownership status, vector-borne diseases were common in these dog populations. There was significant difference of pathogen prevalence among the different dog populations. Mycoplasma spp. was more frequent in the kennel dogs (31.9%) than in the pet (21.4%) and shepherd dogs (13.8%). Additionally, the frequency of Babesia spp. and Hepatozoon spp. was higher in the shepherd dogs which account for three quarters and half of the total number of Babesia spp. and Hepatozoon spp., respectively. To our knowledge, this is the first report of Mycoplasma infection in dogs in Turkey. The results of the present study provide a foundation for understanding the epidemiology of canine vector-borne diseases (CVBDs), and for strategies to control these diseases in Turkey.

Canine Monocytic Ehrlichiosis: An Update on Diagnosis and Treatment

Canine monocytic ehrlichiosis (CME) is a tick-borne disease of worldwide distribution. The major causative agent is Ehrlichia canis, a gram-negative, obligate intracellular, pleomorphic bacterium of the genus Ehrlichia, which infects monocytes, macrophages and lymphocytes, forming intracytoplasmic, membrane-bound bacterial aggregates, called morulae. After an incubation period of 8-20 days, the course of E. canis infection, can be sequentially divided into acute, subclinical and chronic phases, although these phases can hardly be distinguished in the clinical setting. Clinical recovery is the typical outcome of acutely infected dogs, entering the subclinical phase, during which they show no or minimal clinical signs and/or mild hematological abnormalities. Immunocompetent dogs may eliminate the infection during the acute or subclinical phases, but an unpredictable proportion of dogs will eventually develop the chronic phase, characterized by aplastic pancytopenia and high mortality, due to septicemia and/or severe bleeding. This article outlines briefly the pathogenesis of CME due to E. canis, and more thoroughly reviews the recent scientific literature pertaining to the diagnosis and treatment of this devastating disease.

The prevalence of Anaplasma platys and a potential novel Anaplasma species exceed that of Ehrlichia canis in asymptomatic dogs and Rhipicephalus sanguineus in Taiwan

Canine anaplasmosis is regarded as an infection by Anaplasma platys rather than zoonotic Anaplasma phagocytophilum in subtropical areas based on the assumption that the common dog tick species is Rhipicephalus sanguineus, which transmits E. canis and presumably A. platys. We investigated asymptomatic dogs and dog ticks from 16 communities in Nantou County, Taiwan to identify common dog tick species and to determine the prevalence of Anaplasma and Ehrlichia spp. Of total 175 canine blood samples and 315 ticks, including 306 R. sanguineus and 9 Haemaphysalis hystricis, 15 dogs and 3 R. sanguineus ticks were positive for E. canis, while 47 dogs and 71 R. sanguineus ticks were positive for A. platys, via nested PCR for 16S rDNA and DNA sequencing of selected positive amplicons. However, among the dogs and ticks that were positive to A. platys 16S rDNA, only 20 dogs and 11 ticks were positive to nested PCR for A. platys groEL gene. These results revealed the importance of searching for novel Anaplasma spp. closely related to A. platys in dogs and ticks. Seropositivity to a commercial immunochromatographic test SNAP 4Dx Anaplasma sp. was not significantly associated with PCR positivity for A. platys but with infestation by ticks carrying A. platys (P<0.05). Accordingly, R. sanguineus may be involved in transmission of A. platys but may not act as a reservoir of E. canis and PCR results for 16S rDNA could be a problematic diagnostic index for A. platys infection.