Hepatozoon canis infection in ticks during spring and summer in Italy

A Molecular survey of Hepatozoon canis in dogs in the Siirt province of Turkey

This study aimed to determine Hepatozoon canis prevalence in dogs in the Siirt province of Turkey by the molecular method. The animal material of the study consisted of a total of 75 dogs that appeared clinically healthy. Two ml of blood sample were taken from the vena cephalica antebrachii. Then, DNA extraction was performed. Polymerase chain reaction (PCR) was performed to amplify the 666 bp 18S rRNA gene region of Hepatozoon canis. Two positive PCR products were purified and sequenced. As a result of Nested-PCR, H. canis specific bands in 666 bp size were obtained in 7 (9.33%) out of 75 dogs. The result of sequence analysis, the nucleotide sequence was registered in the NCBI GenBank database with accession numbers OL467380.1-OL467538.1. Hepatozoon canis registered in GenBank of sequence OL467380.1 was found to be similar with other H. canis strains of registration numbers MW684292.1 with 99.69% and MH615006.1-MK091085.1-MF797806.1 with 99.53% rates; and the sequence with registration number OL467538.1 was found to be similar to the series MW684291.1 with 99.09% and MH615006.1-MK091085.1-KX 818220.1 with 99.08% rates by BLAST analysis. Hepatozoon canis prevalence of dogs in the Siirt province was determined as a result of this study. It is of great importance to take preventive measures, especially to fight ticks with appropriate acaricides, since there is no vaccine to prevent the disease.

Potential Role of Hepatozoon canis in a Fatal Systemic Disease in a Puppy

Canine hepatozoonosis caused by Hepatozoon canis is an emerging disease in Europe. Clinical pictures vary from subclinical to life-threatening and non-specific clinical signs are predominantly reported. A 2-month-old female puppy originating from Southern Italy was adopted and moved to Northern Italy. Then, the dog was brought to a local veterinary practice for gastrointestinal signs, migrating lameness and pruritic dermatitis, and then tested positive for Hepatozoon spp. gamonts at the blood smear. After treatment with imidocarb dipropionate and doxycycline, the dog showed an initial clinical improvement. However, gastrointestinal signs recurred, and diffuse superficial pyoderma appeared on the thoracolumbar region, along with fever, lethargy, and weight loss. Eight months from the first onset of clinical signs, the dog was referred to a veterinary clinic and subjected to complete blood count, urine and fecal analysis, along with abdominal ultrasonography, whole-body CT and gastroduodenal endoscopy. Skin biopsies and blood samples were subjected to a PCR-coupled sequencing protocol, which scored both positive for H. canis. Alterations were consistent with a pre-existing cholangiohepatitis and multiple acquired extrahepatic shunts secondary to portal hypertension. The dog was euthanatized due to a clinical worsening two months later. The potential role of H. canis in the systemic disease observed, clinic-pathological findings and epizootiological implications are discussed.

Hepatozoon canis in hunting dogs from Southern Italy: distribution and risk factors

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

Thymol action on cells and tissues of the synganglia and salivary glands of Rhipicephalus sanguineus sensu lato females (Acari: Ixodidae)

Thymol is a monoterpene present in plants of the families Lamiaceae, Verbenaceae and Apiaceae. Despite its proven acaricidal activity, little is known about the mechanism of action of thymol in ticks. Thus, the aim of this study was to perform a morpho-histochemical analysis of the synganglion and salivary glands of partially engorged females of the brown dog tick, Rhipicephalus sanguineus sensu lato (s.l.), exposed to thymol at different concentrations. Five groups were established: Control Group I (distilled water), Control Group II (ethanol 30%), Group III (thymol 1.25 mg/mL), Group IV (thymol 2.5 mg/mL) and Group V (thymol 5.0 mg/mL). The females were exposed to the treatments by the immersion method and subsequently kept in a climatic chamber (27 ± 1 °C and relative humidity 80 ± 10%) for five days. After this period, the synganglion and salivary glands were removed, and the hematoxylin/eosin morphological technique was applied. The von Kossa staining method with counterstaining neutral red was performed on the salivary glands. The results showed that females exposed to thymol had damaged synganglia, with pyknotic nuclei and vacuoles in the cortex and subperineurial regions, as well as rupture of the neural lamellae. The salivary glands showed type I acini with a dilated lumen. Cells with extremely vacuolated cytoplasm and fragmented nuclei were observed in type II and III acini. Type II acini of the females exposed to thymol revealed different calcium staining when compared to the Control Groups I and II. We therefore conclude that the salivary glands and synganglion are subject to changes in morphology and calcium levels when exposed to thymol at concentrations of 1.25, 2.5 and 5.0 mg/mL, demonstrating that this monoterpene has acaricidal potential on partially engorged females of R. sanguineus (s.l.).

An Australian dog diagnosed with an exotic tick-borne infection: should Australia still be considered free from Hepatozoon canis?

Recent molecular and sero-surveillance studies of the tick-borne pathogen Hepatozoon canis have identified new hosts, potential vector species, and have revealed that H. canis is more widespread than previously thought. We report the first diagnosed case of canine hepatozoonosis in Australia from a Maremma Sheepdog in Sarina, Queensland. Hepatozoon canis was detected with blood smear examination and 18S rRNA sequencing. It is unknown when or how the organism was introduced into Australia, which raises questions about border biosecurity policies and the H. canis infection status of its potential vectors and hosts in Australia. Surveillance for this pathogen is required to determine whether H. canis has established in Australia.

Endemic, exotic and novel apicomplexan parasites detected during a national study of ticks from companion animals in Australia

BACKGROUND

Apicomplexan tick-borne pathogens that cause disease in companion animals include species of Babesia Starcovici, 1893, Cytauxzoon Neitz & Thomas, 1948, Hepatozoon Miller, 1908 and Theileria Bettencourt, Franca & Borges, 1907. The only apicomplexan tick-borne disease of companion animals that is known to occur in Australia is babesiosis, caused by Babesia canis vogeli Reichenow, 1937 and Babesia gibsoni Patton, 1910. However, no molecular investigations have widely investigated members of Apicomplexa Levine, 1980 in Australian ticks that parasitise dogs, cats or horses, until this present investigation.

RESULTS

Ticks (n = 711) removed from dogs (n = 498), cats (n = 139) and horses (n = 74) throughout Australia were screened for piroplasms and Hepatozoon spp. using conventional PCR and Sanger sequencing. The tick-borne pathogen B. vogeli was identified in two Rhipicephalus sanguineus Latreille ticks from dogs residing in the Northern Territory and Queensland (QLD). Theileria orientalis Yakimov & Sudachenkov, 1931 genotype Ikeda was detected in three Haemaphysalis longicornis Neumann ticks from dogs in New South Wales. Unexpectedly, the exotic tick-borne pathogen Hepatozoon canis James, 1905 was identified in an Ixodes holocyclus Neumann tick from a dog in QLD. Eight novel piroplasm and Hepatozoon species were identified and described in native ticks and named as follows: Babesia lohae n. sp., Babesia mackerrasorum n. sp., Hepatozoon banethi n. sp., Hepatozoon ewingi n. sp., Theileria apogeana n. sp., Theileria palmeri n. sp., Theileria paparinii n. sp. and Theileria worthingtonorum n. sp. Additionally, a novel cf. Sarcocystidae sp. sequence was obtained from Ixodes tasmani Neumann but could not be confidently identified at the genus level.

CONCLUSIONS

Novel species of parasites in ticks represent an unknown threat to the health of companion animals that are bitten by these native tick species. The vector potential of Australian ticks for the newly discovered apicomplexans needs to be assessed, and further clinical and molecular investigations of these parasites, particularly in blood samples from dogs, cats and horses, is required to determine their potential for pathogenicity.

Transstadial Transmission of Hepatozoon canis by Rhipicephalus sanguineus (Acari: Ixodidae) in Field Conditions

This study investigated possible transovarial and transstadial transmission of Hepatozoon canis by Rhipicephalus sanguineus (Latreille) ticks collected from naturally infected dogs in a municipal dog shelter and the grounds of the shelter. Four hundred sixty-five engorged nymphs were collected from 16 stray dogs that were found to be infected with H. canis by blood smear and PCR analyses and maintained in an incubator at 28 °C for moulting. Four hundred eighteen nymphs moulted to adults 14-16 d post collection. Unfed ticks from the shelter grounds comprised 1,500 larvae, 2,100 nymphs, and 85 adults; were sorted according to origin, developmental stage, and sex into 117 pools; and screened by 18S rRNA PCR for Hepatozoon infection. Of 60 adult tick pools examined, 51 were infected with H. canis. The overall maximum likelihood estimate (MLE) of infection rate was calculated as 21.0% (CI 15.80-28.21). Hepatozoon canis was detected in 31 out of 33 female pools (MLE 26.96%, CI 17.64-44.33) and 20 out of 27 male pools (MLE 14.82%, CI 20.15-46.41). Among 42 unfed nymph pools collected from the shelter, 26 were infected with H. canis, and MLE of infection was calculated as 1.9% (CI 1.25-2.77). No H. canis DNA was detected in any of the gDNA pools consisting of larva specimens. Partial sequences of the 18S rRNA gene shared 99-100% similarity with the corresponding H. canis isolates. Our results revealed the transstadial transmission of H. canis by R. sanguineus, both from larva to nymph and from nymph to adult, in field conditions. However, there were no evidence of transovarial transmission.

Dogs, cats, parasites, and humans in Brazil: opening the black box

Dogs and cats in Brazil serve as primary hosts for a considerable number of parasites, which may affect their health and wellbeing. These may include endoparasites (e.g., protozoa, cestodes, trematodes, and nematodes) and ectoparasites (i.e., fleas, lice, mites, and ticks). While some dog and cat parasites are highly host-specific (e.g., Aelurostrongylus abstrusus and Felicola subrostratus for cats, and Angiostrongylus vasorum and Trichodectes canis for dogs), others may easily switch to other hosts, including humans. In fact, several dog and cat parasites (e.g., Toxoplasma gondii, Dipylidium caninum, Ancylostoma caninum, Strongyloides stercoralis, and Toxocara canis) are important not only from a veterinary perspective but also from a medical standpoint. In addition, some of them (e.g., Lynxacarus radovskyi on cats and Rangelia vitalii in dogs) are little known to most veterinary practitioners working in Brazil. This article is a compendium on dog and cat parasites in Brazil and a call for a One Health approach towards a better management of some of these parasites, which may potentially affect humans. Practical aspects related to the diagnosis, treatment, and control of parasitic diseases of dogs and cats in Brazil are discussed.

Transstadial transmission of Hepatozoon canis from larvae to nymphs of Rhipicephalus sanguineus

Hepatozoon canis is an apicomplexan parasite of dogs, which is known to become infected by ingesting Rhipicephalus sanguineus adult ticks. To investigate the possibility of H. canis transovarial and transstadial transmission from larvae to nymphs, engorged adult female ticks were collected from a private animal shelter in southern Italy, where H. canis infection is highly prevalent. Female ticks (n=35) and egg batches were tested by PCR for H. canis. All eggs examined were PCR-negative whereas 88.6% of females from the environment tested positive. Additionally, fed larvae (n=120) from a dog naturally infected by H. canis were dissected at different time points post collection (i.e. 0, 10, 20 and 30 days). Molted nymphs dissected at 20 days post collection revealed immature oocysts displaying an amorphous central structure in 50% of the specimens, and oocysts containing sporocysts with sporozoites were found in 53.3% of the nymphs dissected at 30 days post collection. This study demonstrates that H. canis is not transmitted transovarially, but it is transmitted transstadially from larvae to nymphs of R. sanguineus and develops sporozoites in oocysts that may infect dogs.

High prevalence of Hepatozoon-infection among shepherd dogs in a region considered to be free of Rhipicephalus sanguineus

Blood samples and ticks were collected from 100 shepherd dogs, 12 hunting dogs and 14 stray dogs in southern Hungary, in order to screen them for the presence of Hepatozoon spp. by PCR. Out of 126 blood samples, 33 were positive (26%). Significantly more shepherd dogs (31%) were infected, than hunting (8%) and stray dogs (7%). Three genotypes of Hepatozoon canis were identified by sequencing, differing from each other in up to six nucleotides in the amplified portion of their 18S rRNA gene. In Dermacentor marginatus larvae/nymphs and Dermacentor reticulatus nymphs, H. canis was present only if they had been collected from PCR-positive dogs, and the genotypes were identical in the ticks and their hosts. However, two Haemaphysalis concinna nymphs removed from a PCR-negative dog were found positive for H. canis, and the genotype detected in specimens of this tick species differed from that in the blood of their respective hosts. These results indicate that canine hepatozoonosis may be highly prevalent in regions where Rhipicephalus sanguineus is considered to be non-endemic. In addition, H. canis was identified for the first time in Hungary, as well as in D. marginatus, D. reticulatus and Ha. concinna ticks. Canine hepatozoonosis was significantly more prevalent west of the Danube river (where higher densities of red fox and golden jackal populations occur), suggesting a role of wild carnivores in its epidemiology.