Occurrence of Babesia Species and Co-Infection with Hepatozoon canis in Symptomatic Dogs and in Their Ticks in Eastern Romania

Molecular detection of Hepatozoon canis in dogs from Ibagué, Tolima

The genus Hepatozoon consists of apicomplexan protozoans that affect mammals, birds, amphibians, and reptiles. In dogs, the Hepatozoon species include H. canis and H. americanum, which are transmitted by the Rhipicephalus sanguineus tick and cause nonspecific signs, such as fever, weight loss, diarrhea, and blood disorders. These protozoans have a worldwide distribution in Europe, Asia, Africa, and North and South America, including Colombia. The aim of this study was to determine the prevalence and risk factors associated with H. canis in the urban and rural areas of Ibagué, Colombia. Blood samples were collected from 308 dogs (180 rural areas and 128 urban areas). Collected data included dog breed, sex, age, environmental factors, and the presence of ectoparasites. A fragment of the 18S rRNA gene was amplified by PCR for detection of the pathogen and confirmed by sequencing. Among the 308 samples, 14 were positive (14/308, 4.5%) for the presence of H. canis. The partial sequence of the 18S rRNA gene showed identity values >98% with H. canis, forming a cluster with sequences from Latin America. An epidemiological survey found two protective factors: most of the time at home (P=0.055) and overnight stay at home (P=0.03). This is the first molecular study of the prevalence and phylogeny analysis of H. canis in Ibagué, Colombia. The findings may help determine risk factors and enhance our understanding of the geographic distribution of H. canis in Colombia.

Seasonal Dynamics and Physiological Age of Ixodid Ticks Collected from Dogs

In order to reproduce and complete life cycles, ticks have to feed on different hosts, thus participating as vectors and reservoirs in the maintenance and circulation of different pathogens. Since dogs can serve as suitable hosts for numerous tick species, the aims of this study were to determine tick species and their seasonal occurrence on pet dogs and to compare the accuracy of three indices frequently used to calculate engorged female physiological age. Ticks were collected from dogs brought to veterinary clinics. Three indices were analyzed: scutal index, alloscutal/scutal index ratio, and physiological age index. Four tick species were identified: Ixodes ricinus, Dermacentor marginatus, D. reticulatus, and Rhipicephalus sanguineus group, and the last was the most abundant. The highest number of collected ticks was in April, but two species were continuously active throughout the year. The statistical analyses distinguished the physiological age index as more precise because of lower variability. Dog owners usually ignore regular dog anti-tick treatments throughout the year, as they are not aware that ticks could be active during the winter months. Tick surveillance is unquestionably important in order to monitor and prevent the distribution of these vectors and also the diseases they transmit.

The first report on Hepatozoon canis in dogs and wolves in Poland: clinical and epidemiological features

BACKGROUND

Canine hepatozoonosis caused by Hepatozoon canis is a common infection in dogs, with frequent case reports from the Mediterranean region and more recently from several Central European countries, such as Hungary and Germany. Despite the high prevalence of H. canis in red foxes, no infections have been reported to date in dogs in Poland. We describe here the first autochthonous cases of H. canis infection in dogs, including their clinical features, and report the prevalence of H. canis in grey wolves from different regions of Poland.

METHODS

Thin smears prepared from blood samples collected from dogs were evaluated by microscopic examination. A total of 60 wolves and 47 dogs were tested. Infections were confirmed by PCR and sequencing.

RESULTS

Gamonts of H. canis were found in > 50% of the neutrophils of two dogs and in < 10% of the neutrophils in another five dogs. Molecular typing by PCR sequencing of the 18S ribosomal RNA gene fragment confirmed infections in 11 dogs from different regions of Poland, in 2.7% of dogs attending veterinary practices in central Poland and in 35% of wolves from various geographical regions of Poland. Clinical features manifested mostly in older dogs, and the most common signs were anaemia and apathy. Young dogs usually remained asymptomatic.

CONCLUSIONS

This is the first report of H. canis infection in dogs and wolves in Poland. Although the exact vector of the parasite is not known, veterinary practitioners should be aware of this new parasitosis and should consider appropriate diagnostics to confirm/exclude this infection. Further studies are needed to understand the transmission routes of H. canis in domestic and wild canids in Poland.

Canine Babesiosis Caused by Large Babesia Species: Global Prevalence and Risk Factors-A Review

Canine babesiosis is a disease caused by protozoan pathogens belonging to the genus Babesia. Four species of large Babesia cause canine babesiosis (B. canis, B. rossi, B. vogeli, and the informally named B. coco). Although canine babesiosis has a worldwide distribution, different species occur in specific regions: B. rossi in sub-Saharan Africa, B. canis in Europe and Asia, and B. coco in the Eastern Atlantic United States, while B. vogeli occurs in Africa, southern parts of Europe and Asia, northern Australia, southern regions of North America, and in South America. B. vogeli is the most prevalent large Babesia species globally. This results from its wide range of monotropic vector species, the mild or subclinical nature of infections, and likely the longest evolutionary association with dogs. The most important risk factors for infection by large Babesia spp. include living in rural areas, kennels or animal shelters, or regions endemic for the infection, the season of the year (which is associated with increased tick activity), infestation with ticks, and lack of treatment with acaricides.

Detection and Molecular Characterization of Canine Babesiosis Causative Agent Babesia canis in Naturally Infected Dogs in the Dobrogea Area (Southeastern Romania)

Canine babesiosis is an emerging tick-borne disease of major veterinary concern in Europe. Its prevalence has increased in the last two decades and is spreading rapidly toward the north. The aim of this study was to investigate the genetic diversity of Babesia spp. strains isolated from naturally infected dogs in a tick-endemic area (Dobrogea) in southeastern Romania. For this purpose, a total of twenty-three samples from dogs diagnosed with various clinical forms of babesiosis, evaluated by means of clinical history, physical examination, and hematological tests, were subjected to a molecular investigation using PCR, sequencing analysis, and genetic characterization. A microscopic examination of thin Diff-quick-stained blood smears revealed large intra-erythrocytic Babesia piroplasms in all dogs. The PCR and sequencing analysis results indicated the presence of Babesia canis in 22 dogs (95.7%) and Babesia vogeli in 1 dog (4.3%). Among the B. canis isolates, two genotypes were distinguished based on two nucleotide substitutions (GA→AG) observed in the 18S rRNA gene sequences (at positions 609 and 610), with the AG genotype predominating (54.5% of samples), while the GA variant was identified in 9.1% of samples. In the remaining isolates (36.4%), both variants were identified. The B. vogeli-positive dog also tested positive for antibodies against Ehrlichia canis and displayed severe disease. This study reports, for the first time, the presence of genetically heterogenic B. canis strains in dogs with clinical babesiosis in Romania. These findings provide a basis for future studies on the relationship between the genetic structure of the causative agents of canine babesiosis in Romania and the course of the disease.

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.

Prevalence of Babesia and Ehrlichia in owned dogs with suspected tick-borne infection in Hong Kong, and risk factors associated with Babesia gibsoni

Babesiosis and ehrlichiosis are the most clinically significant tick-borne infections in dogs. Although epidemiological investigations of these diseases have been performed in some Asian regions, little data is available in Hong Kong, where competent vector tick species are endemic. The objectives of this study were to determine the molecular prevalence of Ehrlichia canis and Babesia species (B. canis, B. gibsoni, B. vogeli) in owned dogs suspected of tick-borne infection in Hong Kong and to identify risk factors associated with B. gibsoni infection. Electronic records from the Veterinary Diagnostic Laboratory of City University of Hong Kong were searched to identify canine blood samples submitted for molecular testing of these pathogens by real time PCR between March 2018 and May 2021. Electronic patient records from the affiliated veterinary hospital were searched to identify a subset of tested dogs to investigate the potential risk factors for B. gibsoni infection using logistic regression models. Among 1508 tested dogs for all four pathogens of interest, Babesia spp. were detected in 435 (28.8%) and E. canis in 112 (7.4%). Babesia gibsoni was detected in 408 dogs while B. vogeli was detected in 27 dogs. Babesia canis was not detected in any dog. Co-infections of different combinations of B. gibsoni, B. vogeli and E. canis were present in 25 dogs. In multivariable logistic regression, mixed breed dogs were more likely to be infected with B. gibsoni than purebreds (P = 0.005), while dogs > 10 years of age were less likely to be infected than younger dogs (P = 0.019). Hematological abnormalities significantly associated with B. gibsoni infection included thrombocytopenia, neutropenia, or pancytopenia. Babesiosis caused by B. gibsoni is a common infection in owned dogs suspected of tick-borne infection in Hong Kong. The risk factors reported should be considered in diagnosing dogs suspected of infection with this agent. Furthermore, consideration for testing for B. gibsoni infection should be given if the results of a complete blood count show thrombocytopenia even in the absence of anemia, neutropenia or pancytopenia.

What do we know about the microbiome of I. ricinus?

I. ricinus is an obligate hematophagous parasitic arthropod that is responsible for the transmission of a wide range of zoonotic pathogens including spirochetes of the genus Borrelia, Rickettsia spp., C. burnetii, Anaplasma phagocytophilum and Francisella tularensis, which are part the tick´s microbiome. Most of the studies focus on "pathogens" and only very few elucidate the role of "non-pathogenic" symbiotic microorganisms in I. ricinus. While most of the members of the microbiome are leading an intracellular lifestyle, they are able to complement tick´s nutrition and stress response having a great impact on tick´s survival and transmission of pathogens. The composition of the tick´s microbiome is not consistent and can be tied to the environment, tick species, developmental stage, or specific organ or tissue. Ovarian tissue harbors a stable microbiome consisting mainly but not exclusively of endosymbiotic bacteria, while the microbiome of the digestive system is rather unstable, and together with salivary glands, is mostly comprised of pathogens. The most prevalent endosymbionts found in ticks are Rickettsia spp., Ricketsiella spp., Coxiella-like and Francisella-like endosymbionts, Spiroplasma spp. and Candidatus Midichloria spp. Since microorganisms can modify ticks' behavior, such as mobility, feeding or saliva production, which results in increased survival rates, we aimed to elucidate the potential, tight relationship, and interaction between bacteria of the I. ricinus microbiome. Here we show that endosymbionts including Coxiella-like spp., can provide I. ricinus with different types of vitamin B (B2, B6, B7, B9) essential for eukaryotic organisms. Furthermore, we hypothesize that survival of Wolbachia spp., or the bacterial pathogen A. phagocytophilum can be supported by the tick itself since coinfection with symbiotic Spiroplasma ixodetis provides I. ricinus with complete metabolic pathway of folate biosynthesis necessary for DNA synthesis and cell division. Manipulation of tick´s endosymbiotic microbiome could present a perspective way of I. ricinus control and regulation of spread of emerging bacterial pathogens.

Prevalence of Babesia spp. pathogens in the ticks Dermacentor reticulatus and Ixodes ricinus in the UK

The emergence of Babesia pathogens novel to the UK is of growing concern; these include Babesia canis and Babesia caballi. However, a better understanding of changes in the prevalence of endemic Babesia species such as Babesia venatorum and Babesia divergens is also of importance. Here, the prevalence of Babesia pathogens in both Dermacentor reticulatus and Ixodes ricinus ticks was assessed. Dermacentor reticulatus were collected from six sites known to harbour populations of this species in west Wales and southern England. DNA was extracted from 879 individual ticks and subjected to PCR and sequence analysis. Seven Babesia species were detected in 7.5% of the ticks, including B. caballi (0.68%), B. bovis (1.7%), B. microti (1.02%), B. bigemina (0.34%), B. capreoli (0.34%), and one isolate of B. canis (0.34%). Two of the field sites with grazing equines present had ticks that were positive for B. caballi. For I. ricinus, up to 200 nymphs were collected from each of 24 cattle farms in south-west England. Nymphs were divided into 6 pools of 30 from each farm for DNA extraction, PCR, and sequencing. Samples from seven out of the 24 farms tested positive for Babesia, and most were positive for more than one species. Babesia divergens was identified from five farms, and three of these farms had two pooled samples positive for B. divergens, which given the low overall prevalence rate suggests that B. divergens may be highly clustered within the tick population. Most of the remaining positive samples were Babesia venatorum, demonstrating that this zoonotic pathogen is widespread in livestock habitats. The data suggest that B. canis is not yet widely prevalent in established D. reticulatus populations in the UK, but that there is a need to raise awareness of the risk of equine piroplasmosis in areas with endemic D. reticulatus foci, since B. caballi appears more widely established.