Retrospective study of clinical and hematological aspects associated with dogs naturally infected by Hepatozoon canis in Ludhiana, Punjab, India

Diversity of Hepatozoon species in wild mammals and ticks in Europe

BACKGROUND

Hepatozoon spp. are tick-borne parasites causing subclinical to clinical disease in wild and domestic animals. Aim of this study was to determine Hepatozoon prevalence and species distribution among wild mammals and ticks in Europe.

METHODS

Samples of wild mammals and ticks, originating from Austria, Bosnia and Herzegovina, Croatia, Belgium and the Netherlands, were tested with PCR to amplify a ~ 670-bp fragment of the small subunit ribosomal RNA gene.

RESULTS

Of the 2801 mammal samples that were used for this study, 370 (13.2%) tested positive. Hepatozoon canis was detected in samples of 178 animals (3 Artiodactyla, 173 Carnivora, 1 Eulipotyphia, 1 Lagomorpha), H. martis in 125 (3 Artiodactyla, 122 Carnivora), H. sciuri in 13 (all Rodentia), Hepatozoon sp. in 47 (among which Hepatozoon sp. Vole isolate, all Rodentia) and H. ayorgbor in 4 (all Rodentia). Regarding origin, 2.9% (6/208) tested positive from Austria, 2.8% (1/36) from Bosnia and Herzegovina, 14.6% (173/1186) from Croatia and 13.9% (190/1371) from Belgium/the Netherlands. Of the 754 ticks collected, 0.0% (0/35) Hyalomma sp., 16.0% (4/25) Dermacentor spp., 0.0% (0/23) Haemaphysalis spp., 5.3% (24/50) Ixodes and 1.4% (3/221) Rhipicephalus spp. tested positive for Hepatozoon (4.2%; 32/754), most often H. canis (n = 22).

CONCLUSIONS

Hepatozoon canis is most present in mammals (especially in Carnivora such as gray wolves and golden jackals) and ticks, followed by H. martis, which was found merely in stone martens and pine martens. None of the rodent-associated Hepatozoon spp. were detected in the ticks, suggesting the possible implication of other arthropod species or non-vectorial routes in the transmission cycle of the hemoprotozoans in rodents. Our findings of H. canis in ticks other than R. sanguineus add to the observation that other ticks are also involved in the life cycle of Hepatozoon. Now that presence of Hepatozoon has been demonstrated in red foxes, gray wolves, mustelids and rodents from the Netherlands and/or Belgium, veterinary clinicians should be aware of the possibility of spill-over to domestic animals, such as dogs.

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.

Canine vector-borne pathogens from dogs and ticks from Tamil Nadu, India

Canine vector-borne diseases (CVBDs) pose a major health problem in dogs globally, with the potential to cause zoonoses, in particular in developing countries where scientific knowledge on the topic is minimal. Blood samples and ticks were collected from stray dogs in Tamil Nadu, South India to assess the prevalence of CVBD-causing pathogens (Anaplasma spp., Babesia spp., Ehrlichia spp., Hepatozoon spp., filarioids and Leishmania spp.). Of the 230 dogs examined, 229 (99.6%) were infested by ticks (mean intensity, 5.65) with Rhipicephalus sanguineus sensu lato and Rhipicephalus haemaphysaloides being morphologically identified in the 98.3% and 1.7% of the infested dogs, respectively. Overall, the 67.8% (n = 156) of dogs was positive for at least one pathogen with Hepatozoon canis being the most prevalent (37.8%) followed by Anaplasma platys (22.6%), Ehrlichia canis (16.1%) Babesia vogeli (10%), Anaplasma phagocytophilum (0.4%) and Babesia gibsoni (0.4%). Two filarioids (Dirofilaria sp. "hongkongensis" and Brugia malayi, 0.4%) were diagnosed in sampled animals. Co-infection with H. canis and A. platys was the most prevalent (8.3%, P = 0.00001), whilst all animals scored negative for Leishmania spp.. Out of 295 ticks analysed, 215 R. sanguineus s.l. (75.4%) and 8 R. haemaphysaloides (88.9%) were positive for at least one pathogen with H. canis as the predominant species (42.5%), followed by A. platys (33.8%), E. canis (16.9%), B. vogeli (3.8%) and A. phagocytophilum (0.3%). Fifty-six dogs (35.9%) harboured the same pathogen as the respective tick specimens, while 29 dogs (18.6%) had a different pathogen. Thirteen sequence types (STs) were identified for H. canis, with ST2 (49.4%) as the most representative in dogs and ST1 (73.5%) in ticks. Similarly, seven STs were found for Anaplasma spp. (i.e., five for A. platys, one for A. phagocytophilum and one for Anaplasma sp.), with ST2 as the most representative in dogs (70.6%) and ST3 (52.5%) in ticks for A. platys. Only one ST was identified for B. vogeli, B. gibsoni, E. canis, D. sp. "hongkongensis" and B. malayi. Regular surveillance and adoption of adequate treatment and control measures are needed to reduce the risk of disease-causing pathogens in stray dogs and of pathogens with zoonotic potential.

Detection of Hepatozoon canis in the Brown Dog Tick and Domestic Dogs in Peninsular Malaysia

Hepatozoon canis has been widely reported in dogs. Its prevalence in ticks, however, has not been well-established. Here we determine the occurrence of Hepatozoon DNA in the brown dog tick Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) sensu lato (s.l.) and domestic dogs from Peninsular Malaysia using a polymerase chain reaction (PCR) assay based on amplification of the 18S ribosomal RNA coding sequence. Our results revealed a relatively low prevalence of H. canis DNA in both R. sanguineus s.l. (0.7%) and dogs (3.33%). This study represents the first report of H. canis DNA in R. sanguineus s.l. in Malaysia, highlighting the risk of this infection in dogs.

Novel incidental finding of Hepatozoon canis infection in two dogs of the same household in Trinidad, West Indies

A five-year old mixed breed bitch was presented to the veterinary clinic in lateral recumbency with a history of anorexia and muscle hyperaesthesia. Examination of the blood smear of this animal revealed the presence of Hepatozoon spp. gamonts in the neutrophils and monocytes with a parasitaemia level of approximately 2%. Complete blood count (CBC) revealed a neutrophilia, and a normocytic normochromic non-regenerative anaemia which were consistent with Hepatozoon spp. infections. Diagnosis was confirmed by polymerase chain reaction (PCR) amplification of the 18S rRNA gene followed by DNA sequencing of the amplicon. Although the other dog in the household appeared asymptomatic, Hepatozoon canis infection was confirmed by both microscopic examination of blood smear and PCR. Both dogs were infested with Rhipicephalus sanguineus ticks. Phylogenetic analysis revealed that the H. canis sequences from these two dogs were similar to those from Venezuela and St Kitts but not Brazil. This is the first reported case of Hepatozoon canis infections in dogs in Trinidad that were confirmed by molecular techniques.

Critical analysis of vector-borne infections in dogs: Babesia vogeli, Babesia gibsoni, Ehrlichia canis and Hepatozoon canis in Punjab, India

There are few published studies on various vector borne diseases of dogs in India and most depict clinical infection in dogs, diagnosed by observation of the haemopathogens in stained blood smears. This study provides the first report regarding molecular confirmation and ancestral relationship analysis of blood smears positive cases of assorted haemopathogens in Punjab province of India. On blood smear examination, haemopathogens were observed in 124 out of 778 (15.95%, 95% CI: 13.53- 18.68) blood smears. Further polymerase chain reactions (PCR) was used on bloods smear positive cases to validate the results. Out of 778 blood samples, Babesia gibsoni was most common parasite infecting dogs (15.04%, 95% CI: 12.7-17.72), followed by Ehrlichia canis (0.39%, 95% CI: 0.0-1.13), infection of Babesia vogeli and Hepatozoon canis was same (0.26%, 95% CI: 0.0-0.9). Among various risk factors studied (age, sex, season), prevalence of infection was non-significantly higher in 1-2 year of age group (19.88%, 95% CI: 14.45-26.71), regarding sex same prevalence was recorded (15.94%), and chances of infection was highest in pre-monsoon i.e. summer (18.26%, 95% CI: 14.49-22.76). Phylogenetic analysis revealed ancestral background of Ludhiana isolates of B. vogeli, B. gibsoni, H. canis, and E. canis with the isolates of Philippines, Mongolia and Tunisia.

Hepatozoon canis and Leishmania spp. coinfection in dogs diagnosed with visceral leishmaniasis

This study describes the occurrence of dogs naturally co-infected with Hepatozoon canis and two Leishmania species: L. infantum or L. braziliensis. Four dogs serologically diagnosed with Visceral Leishmaniasis were euthanized. Liver and spleen samples were collected for histopathological analysis and DNA isolation. H. canis meronts were observed in tissues from all four dogs. H. canis infection was confirmed by PCR followed by sequencing of a fragment of 18S rRNA gene. Leishmania detection and typing was confirmed by ITS1' PCR-RFLP and parasite burden was calculated using ssrRNA quantitative qPCR. A DPP - Dual Path platform test was performed. One out (Dog #2) of four animals was asymptomatic. Dogs #1 and #4 were infected by L. infantum and were DPP test positive. Dogs #2 and #3 were infected by L. braziliensis and were DPP test negative. Furthermore, visceral dissemination was observed in Dogs #2 and #3, since L. braziliensis was detected in liver and spleen samples. The visceral dissemination of L. braziliensis associated with systemic signs suggested that this co-infection could influence the parasite burden and disease progression.

Hematological disorders detected in dogs infected by Hepatozoon canis in a municipality in Mato Grosso do Sul State, Brazil

ABSTRACT A retrospective review of hematological reports of nine dogs detected with Hepatozoon canis infection by microscopic examination of blood smears in a laboratory in the municipality of Dourados, Mato Grosso do Sul, Brazil was conducted. This study aimed to evaluate the hematological profile of these infected dogs, in addition to the occurrence of coinfections with other agents that infect blood cells, since studies concerning canine hepatozoonosis in Brazil are scarce and there are some divergences regarding H. canis infection that still require a resolution. The nine cases of H. canis infection were identified among all dogs examined at the studied laboratory in 2009 and 2010, with an occurrence of 7/1,192 (0.59%; 95% CI 0.15 - 1.02%) positive dogs in the first year and 2/1,313 (0.15%; 95% CI 0.02 - 0.55%) cases in 2010. The analysis of the hematological reports showed an occurrence of coinfection between H. canis and other agents in two (2/9; 22.22%; 95% CI 2.81 - 60.00%) dogs, one with E. canis and another with Babesia spp. (1/9; 11.11%; 95% CI 0.28 - 48.24%). Only the blood test of one dog had no alterations, based on reference values. Anemia was the most frequent hematological alteration (6/9; 66.67%; 95% CI 29.93 - 92.51%). Although the occurrence of H. canis infection was low, significative hematological alterations were observed in most infected dogs. Coinfection with Babesia spp. and E. canis was detected in two dogs and the hematological alterations cannot be attributed exclusively to H. canis in these animals. Longitudinal studies would be of fundamental importance to determine the causality of these alterations. These results highlight the importance of differential diagnosis in dogs when there is clinical suspicion of infection by hemoparasites, since the hematological changes in dogs infected by H. canis are quite variable.