Clinical and hematobiochemical response in canine monocytic ehrlichiosis seropositive dogs of Punjab

Ehrlichia canis and Rickettsia conorii Infections in Shelter Dogs: Seropositivity and Implications for Public Health

A cross-sectional study was conducted to gain insight into the epidemiology of canine ehrlichiosis and rickettsiosis in northern Portugal. Specific IgG antibodies to Ehrlichia canis were analysed using a commercial enzyme-linked immunosorbent assay (ELISA), and antibodies to Rickettsia conorii were analysed using a commercial indirect immunofluorescence antibody test (IFAT). A total of 113 dogs from two different shelters were sampled, and seroprevalence values of 0.9% (95% confidence (CI): 0.2-4.8%) for E. canis and 9.7 (95% CI: 5.5-16.6%) for R. conorii were found. Multiple logistic regression investigated risk factors for seropositivity. The odds ratios (ORs) of R. conorii seropositivity were higher for female dogs (OR = 6.429; 95% CI: 1.201-34.407). Dogs seropositive for co-infection (E. canis + R. conorii) were more frequently observed among females (OR = 7.606; CI 95%: 1.478-39.132) and in Shelter 2 (OR = 18.229; 95% CI: 2.190-151.756). These findings show that shelter dogs in northern Portugal are exposed to E. canis and R. conorii, which can affect both canines and humans. It is imperative to adopt a One Health approach to educate the public about the hazards of canine zoonoses and develop legislation and procedures to control their spread and preserve public health.

Ehrlichiosis in Dogs: A Comprehensive Review about the Pathogen and Its Vectors with Emphasis on South and East Asian Countries

Ehrlichiosis in dogs is an emerging vector borne rickettsial zoonotic disease of worldwide distribution. In general, three Ehrlichial species (Ehrlichia canis, E. ewingii, and E. chaffeensis) are involved in infecting dogs. Among them, E. canis is the well-known etiological pathogen affecting platelets, monocytes, and granulocytes. Dogs act as a reservoir, while the main vector responsible for disease transmission is Rhipicephalus sanguineus. However, in east Asian countries, Haemaphysalis longicornis is considered the principal vector for disease transmission. This disease affects multiple organs and systems and has three clinical manifestations, including acute, subclinical, and chronic. Definitive diagnosis involves visualization of morulae on cytology, detection of antibodies through an indirect immunofluorescence test (IFAT), and DNA amplification by polymerase chain reaction (PCR). In canine ehrlichiosis, no predilection of age or sex is observed; however, Siberian Huskies and German Shepherds are more likely to develop severe clinical manifestations. Doxycycline, rifampicin, and minocycline are proven to be effective drugs against canine ehrlichiosis. This review is intended to describe a brief overview of Ehrlichia infection in dogs, its reported prevalence in east and south Asian countries, and the latest knowledge regarding chemotherapy and associated vectors responsible for the disease transmission. This manuscript also identifies the prevailing knowledge gaps which merit further attention by the scientific community.

Haematological Alterations Associated with Selected Vector-Borne Infections and Exposure in Dogs from Pereira, Risaralda, Colombia

Infections due to Ehrlichia, Anaplasma, Dirofilaria, Mycoplasma, Babesia and Hepatozoon continue to be highly prevalent in dogs, especially in tropical and subtropical areas, where vectors of many of them are present. However, many clinical aspects of dogs have not been characterized in detail, including assessing the haematological alterations associated with them, particularly in Colombia and Latin America. A group of 100 dogs with Ehrlichia, Anaplasma, Dirofilaria, Mycoplasma, Babesia and Hepatozoon infections/exposure were assessed by blood smear serology (SNAP4DX) and PCR in Pereira, Colombia. We performed blood counts to evaluate anaemia, leukopenia/leukocytosis, neutropenia, neutrophilia, lymphopenia/lymphocytosis, monocytosis, eosinophilia, and thrombocytopenia, among other alterations. Bivariate analyses were performed on Stata®14, with significant p < 0.05. From the total, 85% presented ≥1 infection (past or present), 66% with coinfections (≥2 pathogens) (Ehrlichia 75%), and 89% presented clinical alterations. A total of 100% showed anaemia, 70% thrombocytopenia, 61% monocytosis, and 47% neutropenia, among other alterations. Additionally, 11% presented pancytopenia and 59% bicytopenia. The median platelet count was lower in infected dogs (126,000 cells/μL) versus non-infected (221,000 cells/μL) (p = 0.003). Thrombocytopenia was higher among infected dogs (75%) versus non-infected (40%) (p = 0.006), with a 91% positive predictive value for infection. Median neutrophil count was lower in infected dogs (6591 cells/μL) versus non-infected (8804 cells/μL) (p = 0.013). Lymphocytosis occurred only among those infected (27%) (p = 0.022). Leukopenia was only observed among infected dogs (13%). Pancytopenia was only observed among infected dogs. Ehrlichiosis and other hematic infections have led to a significant burden of haematological alterations on infected dogs, including pancytopenia in a tenth of them, most with thrombocytopenia and all anemic.

Demonstrating the presence of Ehrlichia canis DNA from different tissues of dogs with suspected subclinical ehrlichiosis

Background

Nowadays, Ehrlichia canis receives increasing attention because of its great morbidity and mortality in animals. Dogs in the subclinical and chronic phases can be asymptomatic, and serological tests show cross-reactivity and fail to differentiate between current and past infections. Moreover, there could be low parasitaemia, and E. canis might be found only in target organs, hence causing results to be negative by polymerase chain reaction (PCR) on blood samples.

Methods

We evaluated by PCR the prevalence of E. canis in blood, liver, spleen, lymph node and bone marrow samples of 59 recently euthanised dogs that had ticks but were clinically healthy.

Results

In total, 52.55% of the blood PCRs for E. canis were negative, yet 61.30% yielded positive results from tissue biopsies and were as follows: 63.15% from bone marrow; 52.63% from liver; 47.36% from spleen; and 15.78% from lymph node. In addition, 33% had infection in three tissues (spleen, liver and bone marrow).

Conclusions

Our results show the prevalence of E. canis from tissues of dogs that were negative by blood PCR. Ehrlichia canis DNA in tissue was 30% lower in dogs that tested negative in PCR of blood samples compared to those that were positive. However, it must be taken into account that some dogs with negative results were positive for E. canis in other tissues.

Prevalence of protozoan parasitic infections in domestic dogs in Andhra Pradesh, India

Faecal (2,250) and blood samples (1,350) of dogs received from Teaching Veterinary Clinical Complex (TVCC), Gannavaram, Veterinary Hospitals in and around Krishna district and nearby Krishna, Andhra Pradesh during last five years (January 2014 to December 2018) were examined to determine the prevalence of protozoan parasites. Faecal samples were analyzed by direct smear and floatation technique and blood samples after Giemsa's staining. The overall prevalence of protozoan parasitic infections including intestinal (15.60%) and haemoprotozoan (6.22%) infections was 12.10% (n=435). Six genera of protozoan parasites namely Cystisospora, Entamoeba, Ehrlichia, Trypanosoma, Babesia and Hepatozoon were identified. The most prevalent species was Cystoisospora (14.04%) and Hepatozoan canis (0.67%) was the least prevalent species. A significant relationship between age group, breed and prevalence of protozoan parasitism was observed. The prevalence of gastrointestinal and haemoprotozoan parasites was significant during winter and rainy seasons, respectively. Sex did not influence the overall prevalence of protozoan parasites.

Seroprevalences of Rickettsia conorii, Ehrlichia canis and Coxiella burnetii in Dogs from Montenegro

PURPOSE

The incidence of vector-borne zoonoses has been increasing in Europe as a result of global climate change, and rickettsioses are a significant etiologic entity among these infections. The objective of this study was to investigate the seroprevalences of Rickettsia conorii, Ehrlichia canis and Coxiella burnetii in dogs in Montenegro.

METHODS

The seroepidemiological study covered 259 dogs, of which 155 were owned dogs suspected of infection with agents of rickettsial aetiology from the continental (Podgorica) or five coastal municipalities of Montenegro (Budva, Herceg Novi, Kotor, Ulcinj and Bar), and 104 dogs were from a public shelter in Podgorica. The presence of specific IgG antibodies against R. conorii was analysed using a commercial indirect enzyme-linked immunosorbent assay (ELISA) test, and the presence of antibodies against E. canis and C. burnetii was analysed using commercial indirect immunofluorescence tests (IFAT).

RESULTS

Seroprevalences of 73.36, 19.3 and 1.16% were determined for R. conorii, E. canis and C. burnetii, respectively. R. conorii was significantly more prevalent (χ² = 14.53; p < 0.001) in owned dogs (81.93%) than in dogs from the public shelter (60.6%), while E. canis was more prevalent (χ² = 12.31; p < 0.001) in dogs from the public shelter (29.81%) than in owned dogs (12.26%). Coinfection with two pathogens was determined in 40 (15.44%) dogs, and the prevalence of R. conorii/E. canis (χ² = 4.23; p < 0.05) was greater in dogs from the public shelter (20.19%) than in owned dogs (10.97%).

CONCLUSION

The prevailing evidence from this study shows that dogs from Montenegro are exposed to pathogens of veterinary and public health importance. This calls for the One Health approach to sensitise the public on the risks of zoonoses from dogs and to formulate policies and strategies to mitigate their spread and safeguard public health.

Canine Monocytic Ehrlichiosis among working dogs of organised kennels in India: A comprehensive analyses of clinico-pathology, serological and molecular epidemiological approach

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Significant difference was observed between molecular and sero-prevalence of E. canis.

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Phylogenetic analysis revealed divergence in isolates from Brazil & USA.

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Prevalence studies for CME should also involve screening of apparently healthy dogs.

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Concurrent infection of CME and Babesia gibsoni in working dogs was found to be fatal.

Canine Monocytic Ehrlichiosis (CME) is a serious tick-borne rickettsial disease affecting canine populations globally. Besides few reports from stray and pet dogs from localised geographical regions (cities/towns/small states), a comprehensive study on prevalence of Ehrlichia canis (E. canis) among working dogs from different geo-climatic zones of India was pertinently lacking. Study of CME among these dog populations was thus carried out, encompassing clinical aspects and different diagnostic methodologies viz., microscopy, serology and molecular biology. During the two-year study period, clinical specimens from 225 cases suspected of canine ehrlichiosis were examined for clinical pathology and presence of the haemoparasites. Overall prevalence of ehrlichiosis by microscopic examination, commercial dot-ELISA kit and nested PCR assay was estimated to be 1.3%, 19.1% and 5.8%, respectively, which were found to be statistically significant by McNemar Chi squared test (p < 0.05). It was also observed that possibly due to widespread use of doxycycline therapy in field, CME presently does not remain a potential threat which it uses to pose earlier. However, concurrent infections of E. canis and Babesia gibsoni were found to be mostly fatal. Keeping in view of high number of apparently healthy dogs (24) out of total positive cases (46) observed during the study, it is recommended that prevalence studies on CME should also involve screening of apparently healthy dogs. Phylogenetic analysis carried on partial sequencing of 16S rRNA of E. canis strains revealed that all of the Indian strains clustered in a single clade with other E. canis species from India and rest of the world. Molecular divergence was observed among the sequences of Brazilian and American isolates which were also included in the present study. These findings have thus opened a new paradigm for planning of pragmatic control strategies against CME.