Retrospective analysis of canine monocytic ehrlichiosis in Thailand with emphasis on hematological and ultrasonographic changes

Background and Aim: Canine monocytic ehrlichiosis (CME) is a tropical endemic tick-borne disease that causes fatality or chronic infection involving many organs in dogs. This study aimed to examine the prevalence, risk factors, and hematological and ultrasonographic changes in the liver, gallbladder, kidneys, and spleen following CME infection. Materials and Methods: This retrospective study used 30,269 samples collected from dogs at the hematology section of the pathology unit of a university veterinary hospital and 35 samples collected from dogs at the diagnostic imaging unit. CME was determined using the buffy coat smear method. Data were analyzed using descriptive statistics and odds ratios. Results: CCl4 The data revealed that the average yearly prevalence of CME was 1.32%. Risk factors contributing to CME infection were a tick on the body during physical examination, lack of ectoparasite control, and outdoor living. All 148 dogs with CME infection had low platelet counts. The percentages of CME-infected dogs with elevated serum alanine aminotransferase, alkaline phosphatase, and both enzymes above the normal range were 33.6%, 65.9%, and 29.8%, respectively. The rates for elevated serum levels of blood urea nitrogen, creatinine, and both compounds were 33.1%, 19.1%, and 17.3%, respectively. The most common ultrasonographic changes were liver abnormalities (hyperechogenicity or hypoechogenicity, hepatomegaly, and hypoechoic nodules), hyperechogenicity of the kidneys, and an enlarged spleen. These ultrasonographic changes were consistent with the hematology results, which showed a greater elevation of serum liver enzyme levels than renal enzymes. Conclusion: Ultrasonographic changes during CME infection and after treatment with doxycycline can help to monitor and identify persistent pathological changes in the target organs resulting from immune response to CME.

Hematological and histopathological changes in medular aplasia resulting from Ehrlichia canis infection in a Border collie dog

The Canine Monocytic Ehrlichiosis (CME) is an infectious disease that commonly affects dogs of all breeds and ages. It is caused by the bacterium Ehrlichia canis and is transmitted by the tick Rhipicephalus sanguineus. The disease may pre-sent itself in the acute, subclinical, and chronic forms. The present study reports the case of a 2-year-old male Border Collie with advanced stage CME, attended at the Pet Clinic of the Veterinary Hospital of the University Federal de Jataí, which resul-ted in medullary aplasia. The diagnosis of marrow aplasia was based on the necroscopic and histopathological examinations. At necropsy, the diaphyses of the long bones were filled with diffuse, strongly whitish and pasty tissue, typical of the adipose tissue, also found in the femoral epiphyses. The histopathology showed unilocular adipose tissue as the major constituent of the bone marrow and rare islands of marrow cells. These findings were compatible with severe hypoplasia of the red bone mar-row and hyperplasia of the white bone marrow, affecting hematopoiesis, resulting in the laboratory alterations observed in the hematocrit, WBC, and plateletogram.

A Case Study of Assessment of Haemato-Biochemical Profile, Clinical Diagnosis and Therapeutic Management of Canine Monocytic Ehrlichiosis (Tropical Canine Pancytopenia) In A Male Doberman DOG

Ehrlichia canis is an obligate intracellular rickettsial agent that is transmitted by a brown dog tick called as Rhipicephalus sanguineus which is considered as the principal vector of this disease. A 3-year-old male Doberman dog weighing 25 kg is presented with the history of inappetence, fever, weakness, anemia, scanty feces, hemoglobinuria, shrunken eye ball with mild corneal opacity and reluctant to walk due to pain in the joints. Clinical examination revealed elevated rectal temperature of 104.30F, tachycardia, increased respiratory rate and pale mucous membrane. Blood and serum samples were collected for hematology and serum biochemistry respectively. On blood smear examination with Giemsa staining, Ehrlichia morulae were noticed in monocytes suggestive of Canine Monocytic Ehrlichiosis / Tropical Canine Pancytopenia.

Alteration in Serum Cystatin-C and SDMA as biomarkers of early renal dysfunction associated with Canine Monocytic Ehrlichiosis (CME)

Present study was carried out on 30 dogs, positive for ehrlichiosis in nested PCR. Important clinical symptoms exhibited by the canine monocytic ehrlichiosis (CME) positive dogs were mucosal pallor, epistaxis, ascites, ecchymotic and petechial hemorrhages, corneal opacity, icterus and vomiting. All positive dogs were divided into two group (each containing 15 dogs) for the purpose of providing different therapeutic intervention. Six healthy dogs irrespective of age sex or breed were taken as control for comparison of parameters. Whole blood was collected and serum was separated by using standard protocol and serum cystatin C and symmetric dimethylarginine (SDMA) were estimated by using commercial ELISA kit. There was significant increase in serum cystatin C and serum symmetric dimethylarginine (SDMA) in both the treatment groups of dogs in comparison with control. However, there was non-significant decrease in serum cystatin C and SDMA on day 14 post-treatment in both the treatment groups. Total 17 (56.67%) dogs were found to have higher serum cystatin C out of which 10 (33.33%) dogs were also having elevated serum creatinine while remaining 7 (23.33%) dogs were having normal creatinine values. Elevated serum level of SDMA was found in15 (50%) dogs of which 10 (33.33%) were also having concurrent higher creatinine while 5 (16.67%) dogs were have normal creatinine value in spite of having elevated SDMA level. Results indicate the early rise of serum cystatin C and SDMA during renal damage which may considered as better biomarkers for early screening of renal impairment associated with canine monocytic ehrlichiosis (CME).

Molecular Detection of Ehrlichia canis in the Pet-Dog Population in R. N. Macedonia

Canine monocytic ehrlichiosis (CME) is a widespread, tick-borne, canine disease, caused by an obligate intracellular bacterium, Ehrlichia canis. The main vector, a brown-dog tick, Rhipicephalus sanguineus, is widely distributed, especially in areas with tropic, subtropic, or Mediterranean climates (Central and South America, Eastern and Western Asia, Africa, Australia and Southern Europe). The study performed in 2012, by Stefanovska et al., determined a seroprevalence of 18.7% of E. canis among the Macedonian dog population. Up to date, the presence of E. canis, using molecular diagnostic methods, has not been investigated in Macedonia. Therefore, this study aimed to confirm the presence of E. canis, in the pet-dog population on the territory of the city of Skopje, North Macedonia, using a highly sensitive multiplex Real-Time PCR method (qPCR). Whole blood samples from 80 dogs of different breeds and ages, with clinical symptoms of CME and positive serology result for the presence of antibodies against E.canis, were collected for analyses. Out of 80 dogs, 36 (45%) were found as positive. The present work reports the first molecular detection of E. canis in pet dogs on the territory of the city of Skopje, Macedonia.

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.

Analysis on the prokaryotic microbiome in females and embryonic cell cultures of Rhipicephalus sanguineus tropical and temperate lineages from two specific localities in Brazil

Two lineages of Rhipicephalus sanguineus are known in Brazil: the temperate or southern and the tropical or northern populations. The distribution patterns of both lineages of R. sanguineus have epidemiological implications that can affect vectorial competence concerning Ehrlichia canis, the agent of canine monocytic ehrlichiosis. Intending to identify the microbiomes of both lineages and compare microorganisms in R. sanguineus, we used the 16S rRNA (V4-V5 region) gene-based metataxonomic approach, through NGS sequencing on the MiSeq Illumina platform. We selected specimens of females from the environment and samples of primary embryonic cell cultures, from both lineages, and this was the first study to investigate the prokaryotic microbiome in tick cell cultures. The results showed that many bacterial taxa detected in the samples were typical members of the host environment. A significant diversity of microorganisms in R. sanguineus females and in embryonic cell cultures from both lineages was found, with emphasis on the presence of Coxiella in all samples, albeit in different proportions. The Coxiella species present in the two lineages of ticks may be different and may have co-evolved with them, thus driving different patterns of interactions between ticks and the pathogens that they can harbor or transmit to vertebrate hosts.

The emergence of tick-borne diseases in domestic animals in Australia.

In this expert opinion, two case studies of tick-borne diseases of domestic animals in Australia have been selected to illustrate how climate change can potentially influence the spread of introduced tick species and the pathogens they transmit. The first reports an incursion of canine monocytic ehrlichiosis (CME) into northern regions of Australia in April/June 2020 and the second describes the geographical expansion of bovine anaemia due to Theileria orientalis group (BATOG) across Australia since 2006. The introduction of novel pathogens into ecosystems exposed to climate change provides a unique opportunity to study disease dynamics in real time.

New sensitive real-time PCR targeting p28 gene for detection of Ehrlichia canis in blood samples from dogs

ABSTRACT: This study aims to describe a new detection method of a quantitative real-time polymerase chain reaction (qPCR) targeting the 28 kDa outer membrane protein gene (p28) as well as to compare this method with a conventional PCR (cPCR), which targets the same gene, in order to evaluate the performance of the technique designed in this study in detecting Ehrlichia canis (E. canis). Optimum oligonucleotides concentrations were reached, and the analytical sensitivity and specificity of the qPCR were performed. A total of 218 dogs’ whole blood samples were conventionally collected for this study. The DNA was extracted from each sample. Subsequently, the samples were tested by an established cPCR and the new qPCR to compare each technique’s performances. This new qPCR method for the molecular detection of E. canis presented a detection limit of ten copies of the fragment and was considered specific for E. canis according to analytical specificity analyses performed in vitro and in silico. The standard curve revealed 100% efficiency and a coefficient of determination (R2) equivalent to 99.8%. Among the samples examined by qPCR, 24.31% were considered positive, significantly greater than those detected by cPCR (15.13%). The qPCR technique reached a higher sensitivity than the cPCR when targeting the p28 gene in detecting E. canis. The qPCR standardized in this study is an efficient method for confirming canine monocytic ehrlichiosis (CME) diagnosis and might provide the parasitemia monitoring during the disease treatment.