First molecular characterization of a granulocytic Ehrlichia strain isolated from a dog in South Italy

gltA typing of Anaplasma strains related to A. platys: Taxonomical and one health implications

Species belonging to the genus Anaplasma (Rickettsiales) include bacteria of veterinary and public health importance. Beside the zoonotic Anaplasma phagocytophilum, A. platys, the etiological agent of canine cyclic thrombocytopenia, has been sporadically reported in clinically ill human patients. The ongoing emergence of novel strains related to this species in vertebrate hosts emphasises the need for genetic comparisons among strains identified in different regions of the world. In this paper we developed a PCR test suitable for amplification of the still undescribed gltA gene of Anaplasma strains related to A. platys from Mediterranean ruminants and applied on a panel of 248 samples. gltA sequencing allowed phylogenetic comparison with strains related to A. platys recently identified in China, and strains representative of the Anaplasmataceae family. Results suggest the designation of Candidatus A. turritanum, including Mediterranean A. platys - like strains, and Candidatus A. cinensis, including strains isolated in China. Data generated in this study are a solid reference for future epidemiological studies of novel unclassified strains related to A. platys and for their diagnosis and raise concern on their potential veterinary and public health implications encouraging investigating the suspected unexplored diversity within the genus Anaplasma in animals and human.

Rickettsiales in Italy

There is no updated information on the spread of Rickettsiales in Italy. The purpose of our study is to take stock of the situation on Rickettsiales in Italy by focusing attention on the species identified by molecular methods in humans, in bloodsucking arthropods that could potentially attack humans, and in animals, possible hosts of these Rickettsiales. A computerized search without language restriction was conducted using PubMed updated as of December 31, 2020. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was followed. Overall, 36 species of microorganisms belonging to Rickettsiales were found. The only species identified in human tissues were Anaplasma phagocytophilum,Rickettsia conorii, R. conorii subsp. israelensis, R. monacensis, R. massiliae, and R. slovaca. Microorganisms transmissible by bloodsucking arthropods could cause humans pathologies not yet well characterized. It should become routine to study the pathogens present in ticks that have bitten a man and at the same time that molecular studies for the search for Rickettsiales can be performed routinely in people who have suffered bites from bloodsucking arthropods.

Serological evidence of exposure to Ehrlichia canis and Anaplasma phagocytophilum in Central Italian healthy domestic cats

The aim of the present survey was to estimate the seroprevalences of Ehrlichia canis and Anaplasma phagocytophilum in the Central Italian feline population. Serum samples of 560 healthy domestic cats were examined by indirect immunofluorescence assay (IFAT), considering an antibody titre of 1:40 as cut-off. Seroprevalences of 6.4% and 4.5% were found for E. canis and A. phagocytophilum, respectively. Adult, mixed breed cats showed seroprevalences higher than younger and purebred subjects, whereas no differences were observed in relation to gender and living conditions.

Clinicopathological and molecular findings in a case of canine Anaplasma phagocytophilum infection in Northern Italy

A documented case of canine granulocytic anaplasmosis coupled with the molecular characterization of the etiological agent is reported for the first time in Northern Italy. The patient showed nonspecific clinical signs such as fever and weight loss. The most relevant clinicopathological findings were thrombocytopenia, hypoalbuminemia, and normal azotemic proteinuria consistent with glomerular diseases. Blood smear examination revealed the presence of intracytoplasmatic inclusions in neutrophils associated with high positive serology for Anaplasma phagocytophilum. PCR analysis and sequencing of the amplicon confirm serological diagnosis of A. phagocytophilum. Phylogenetic analysis evidenced that the detected bacterial strain belongs to the A. phagocytophilum Europe 1 lineage. Data indicates that A. phagocytophilum circulates in natural environments of Emilia-Romagna region (Northern Italy) and its prevalence in dogs could be underestimated because the clinical signs are frequently nonspecific and a certain diagnosis requires the combination of clinicopathological and molecular assays. Pets living in this area should be regularly monitored and treated for ectoparasites to minimize health risks for humans and pets. Also, surveillance of A. phagocytophilum should be improved in Northern Italy and canine anaplasmosis should be considered in differential diagnosis of persistent proteinuria.

Association between Anaplasma phagocytophilum seroprevalence in dogs and distribution of Ixodes ricinus and Ixodes persulcatus ticks in Latvia

Anaplasma phagocytophilum has been detected in ticks in Latvia; however, this is the first study to investigate this pathogen in dogs in Latvia. The aims of this study were: (i) to determine A. phagocytophilum seroprevalence in dogs, (ii) to correlate A. phagocytophilum seroprevalence in dogs with the geographic distribution of the tick species Ixodes ricinus and Ixodes persulcatus, and (iii) to determine if seroprevalence for A. phagocytophilum is higher in dogs with clinical signs suggestive of canine granulocytic anaplasmosis (CGA). Peripheral venous blood samples were collected from 3 dog groups: (i) clinically healthy dogs (HD, n=400), (ii) clinically healthy hunting dogs (HHD, n=41), and (iii) dogs with a clinical suspicion of anaplasmosis (SD, n=29). Sampling was carried out in regions inhabited by I. ricinus (IR), I. persulcatus (IP), and in regions where both tick species were present (M). SNAP 4Dx test (IDEXX) was used to detect antibodies against A. phagocytophilum in the blood of all dogs; nested PCR was performed in selected dogs of the SD group. Seroprevalence for A. phagocytophilum was calculated and correlated with the prevalent tick species in the region. A. phagocytophilum seroprevalence was 11.0% in HD, 12% in HHD, and 17% in SD with no significant differences among groups. In the IR region, seroprevalence was 12.5% (34/272) while seroprevalence in the M region was 17% (13/76), and both were significantly higher than the seroprevalence of 2% in the IP region (2/93; p<0.0005). One CGA case was diagnosed. We conclude that A. phagocytophilum seroprevalence in Latvia is within the range reported from other European countries. CGA should be included in the differential list in Latvian dogs with appropriate clinical signs and laboratory abnormalities, especially in I. ricinus habitat areas.

The natural history of Anaplasma phagocytophilum

Anaplasma phagocytophilum is the recently designated name replacing three species of granulocytic bacteria, Ehrlichia phagocytophila, Ehrlichia equi and the agent of human granulocytic ehrlichiosis, after the recent reorganization of the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales. Tick-borne fever (TBF), which is caused by the prototype of A. phagocytophilum, was first described in 1932 in Scotland. A similar disease caused by a related granulocytic agent was first described in horses in the USA in 1969; this was followed by the description of two distinct granulocytic agents causing similar diseases in dogs in the USA in 1971 and 1982. Until the discovery of human granulocytic anaplasmosis (HGA) in the USA in 1994, these organisms were thought to be distinct species of bacteria infecting specific domestic animals and free-living reservoirs. It is now widely accepted that the agents affecting different animal hosts are variants of the same Gram-negative obligatory intracellular bacterium, which is transmitted by hard ticks belonging to the Ixodes persulcatus complex. One of its fascinating features is that it infects and actively grows in neutrophils by employing an array of mechanisms to subvert their bactericidal activity. It is also able to survive within an apparently immune host by employing a complex mechanism of antigenic variation. Ruminants with TBF and humans with HGA develop severe febrile reaction, bacteraemia and leukopenia due to neutropenia, lymphocytopenia and thrombocytopenia within a week of exposure to a tick bite. Because of the severe haematological disorders lasting for several days and other adverse effects on the host's immune functions, infected animals and humans are more susceptible to other infections.

Serological and molecular survey of Anaplasma species infection in dogs with suspected tickborne disease in Portugal

Fifty-five dogs with suspected tickborne disease were tested by immunofluorescence assay and PCR for Anaplasma phagocytophilum infection. Thirty (54.5 per cent) of the dogs were seropositive and five of them fulfilled the serological criteria for an active infection, with either seroconversion or a fourfold increase in antibody titres. Fragments of DNA of the expected size were detected by PCR in two seropositive and three seronegative dogs. However, direct amplicon sequencing failed to identify active A phagocytophilum infections, but revealed the presence of Anaplasma platys DNA in the PCR-positive animals.

Anaplasma phagocytophilum in ruminants in Europe

The agent that causes tick-borne fever (TBF) in sheep was first described in 1940, 8 years after the disease was first recognized in Scotland. The same agent was soon shown to cause TBF in sheep and pasture fever in cattle in other parts of the UK, Scandinavia, and other parts of Europe. After the initial use of the name Rickettsia phagocytophila, the organism was given the name Cytoecetes phagocytophila to reflect its association with granulocytes and its morphological similarity with Cytoecetes microti. This name continued to be used by workers in the UK until the recent reclassification of the granulocytic ehrlichiae affecting ruminants, horses, and humans as variants of the same species, Anaplasma phagocytophilum. TBF and pasture fever are characterized by high fever, recurrent bacteremia, neutropenia, lymphocytopenia, thrombocytopenia, and general immunosuppression, resulting in more severe secondary infections such as tick pyemia, pneumonic pasteurellosis, listeriosis, and enterotoxemia. During the peak period of bacteremia as many as 90% of granulocytes may be infected. The agent is transmitted transtadially by the hard tick Ixodes ricinus, and possibly other ticks. After patent bacteremia, sheep, goats, and cattle become persistently infected "carriers," perhaps playing an important role in the maintenance of infection, in the flock/herd. Little is known about how efficiently ticks acquire and maintain infection in ruminant populations or whether "carrier" domestic ruminants play an important role as reservoirs of infection, but deer, other free-living ruminants, and wild rodents are also potential sources of infection. During the late 1990s serological evidence of infection of humans was demonstrated in several European countries, creating a renewed interest and increased awareness of the zoonotic potential of TBF variants. More recently, a few cases of human granulocytic anaplasmosis (HGA) have been reported in some European countries, but it remains to be established whether the variants causing HGA in Europe are genetically and biologically different from those causing TBF in ruminants. TBF is readily diagnosed by demonstrating intracytoplasmic inclusions in peripheral blood granulocytes or monocytes of febrile animals or by detecting specific DNA by polymerase chain reaction (PCR), and TBF variants of A. phagocytophilum can be cultivated in tick cell lines, but the differentiation of TBF variants from HGA variants awaits further investigations.

Characterization of Anaplasma phagocytophilum major surface protein 5 and the extent of its cross-reactivity with A. marginale

Major surface protein 5 (Msp5) of Anaplasma marginale is highly conserved in the genus Anaplasma and the antigen used in a commercially available competitive enzyme-linked immunosorbent assay (cELISA) for serologic identification of cattle with anaplasmosis. This study analyzes the degrees of conservation of Msp5 among various isolates of Anaplasma phagocytophilum and the extent of serologic cross-reactivity between recombinant Msp5 (rMsp5) of Anaplasma marginale and A. phagocytophilum. The msp5 genes from various isolates of A. phagocytophilum were sequenced and compared. rMsp5 proteins of A. phagocytophilum and A. marginale were used separately in an indirect ELISA to detect cross-reactivity in serum samples from humans and dogs infected with A. phagocytophilum and cattle infected with A. marginale. Serum samples were also tested with a commercially available competitive ELISA that uses monoclonal antibody ANAF16C1. There were 100% sequence identities in the msp5 genes among all of the A. phagocytophilum isolates from the United States and a horse isolate from Sweden. Sheep isolates from Norway and dog isolates from Sweden were 99% identical to one another but differed in 17 base pairs from the United States isolates and the horse isolate. Serologic cross-reactivity was identified when serum samples from cattle infected with A. marginale were reacted with rMsp5 of A. phagocytophilum and when serum samples from humans and dogs infected with A. phagocytophilum were reacted with rMsp5 of A. marginale in an indirect-ELISA format. Serum samples from dogs or humans infected with A. phagocytophilum did not cross-react with rMsp5 of A. marginale when tested with the commercially available cELISA. These results suggest that rMsp5 of A. phagocytophilum is highly conserved among United States and European isolates and that serologic distinction between A. phagocytophilum and A. marginale infections cannot be accomplished if rMsp5 from either organism is used in an indirect ELISA.

Molecular Survey of Ehrlichia canis and Anaplasma phagocytophilum from Blood of Dogs in Italy

We investigated the prevalence of Ehrlichia canis (E. canis) (n = 601) and Anaplasma phagocytophilum (A. phagocytophilum) (n = 460) infection by means of real-time PCR from blood of Italian dogs. The prevalence of E. canis in northern, central, and southern Italy was 2.9%, 8%, and 9.7%, respectively. The prevalence of A. phagocytophilum was 0%.

New Findings on Anaplasmosis Caused by Infection withAnaplasma phagocytophilum

Ixodes ricinus (I. ricinus) is one of the vectors of Anaplasma phagocytophilum (A. phagocytophilum) in Europe, in which rates of infection range from 1.9% to 34%. In 1998, human granulocytic ehrlichiosis-like (HGE-like) Ehrlichia DNA was detected in Italy, by PCR technique in one I. ricinus nymph out of 55 ticks that were examined. In 1996, 6.3% of 310 human sera in high-risk subjects from Italy were found positive for antibodies to Ehrlichia phagocytophila (E. phagocytophila). In the same year, the authors reported the first case of equine granulocytic ehrlichiosis. In 1997, only 2 out of 563 equine blood samples examined were found positive for antibodies to E. phagocytophila in the Latium region. In 1998, serological positivity was not observed in 14 symptomatic race horses. In 2002, a symptomatic horse living in Rome was found positive for Ehrlichia equi (E. equi) antibodies, as confirmed by PCR. E. equi was also demonstrated in horses by detection of specific antibodies from two asymptomatic ponies. We tested 128 sera from sheep in different flocks, and antibodies to E. phagocytophila were detected in 17 sera (13.3%) of these sheep. From 2000 to 2004, 147 dog sera were tested for antibodies against A. phagocytophilum, and 7 of these sera were positive (4.8%). These data confirm the presence of the infection in human, domestic animals, and pets in Italy. Studies are under way to correlate the distributions of the disease and tick vector, I. ricinus.

Molecular Diagnosis of Granulocytic Anaplasmosis and Infectious Cyclic Thrombocytopenia by PCR-RFLP

Anaplasma phagocytophilum (A. phagocytophilum, formerly Ehrlichia phagocytophila) is a tick-borne pathogen responsible for tick-borne fever in ruminants, equine granulocytic ehrlichiosis (EGE) in horses, canine granulocytic ehrlichiosis (CGE) in dogs, and for human granulocytic ehrlichiosis (HGE). Human cases have been registered in many countries with a broad range of symptoms and pathogenicity. This article focused on Sardinia as the prevalence in humans was almost seven times higher than in the rest of Italy. To evaluate the risk, blood samples were collected from dogs and horses on the island. Genomic DNA was extracted from the buffy coat and amplified by heminested polymerase chain reaction (PCR) using the groEL gene primers. The first PCR reaction amplified a 624-bp fragment for both A. phagocytophilum and A. platys while the second PCR reaction amplified 573-bp and 515-bp fragments for the above two pathogens, respectively. Six A. phagocytophilum samples were PCR positive (3 dogs and 3 horses) while another dog was A. platys PCR positive. A phylogenetic analysis was conducted with A. phagocytophilum sequences in GenBank from the United States, Slovenia, Switzerland, Germany, UK, Austria, and Czech Republic. Surprisingly, the related phylogenetic tree showed that the Sardinian isolates were closer to the American isolates, which were showing highest mortality rates than from the other two European lineages.

Equine and canine Anaplasma phagocytophilum strains isolated on the island of Sardinia (Italy) are phylogenetically related to pathogenic strains from the United States

The presence of Anaplasma phagocytophilum, a tick-transmitted zoonotic pathogen, was investigated in Sardinia using a molecular approach. Phylogenetic analysis revealed that Sardinian strains are genetically distinct from the two lineages previously described in Europe and are closely related to strains isolated in different areas of the United States.