Diversity of groESL sequences of Anaplasma phagocytophilum among dogs in Slovenia

Molecular detection and phylogeny of Anaplasma spp. closely related to Anaplasma phagocytophilum in small ruminants from China

The genus Anaplasma comprises eight bacterial species that are obligate intracellular pathogens that affect human and animal health. The zoonotic species A. phagocytophilum is the causative agent of tick-borne fever in ruminants, and of granulocytic anaplasmosis in horses, dogs, and humans. Recently, novel strains related to A. phagocytophilum (A. phagocytophilum-like 1/Japanese variant and A. phagocytophilum-like 2/Chinese variant) have been identified. The aim of this study was to reveal the prevalence and phylogeny of A. phagocytophilum and related stains in small ruminants and ticks in China based on sequences of the 16S rRNA combined restriction fragment length polymorphism (RFLP) and groEL genes. PCR-RFLP and phylogenetic analyses based on the 16S rRNA gene showed the presence of A. phagocytophilum-like 1 and 2 variants in sampled animals from China, with prevalence rates of 22.6% (303/1338) and 0.7% (10/1338), respectively. Only A. phagocytophilum-like 1 DNA was found in Haemaphysalis longicornis. The phylogeny based on the groEL gene showed inclusion of A. phagocytophilum-like 1 and some A. phagocytophilum-like 2 strains in two unique clades distinct from, but related to, Japanese and Chinese strains of related A. phagocytophilum, respectively. One noteworthy result was that the SSAP2f/SSAP2r primers detected Ehrlichia spp. strains. Moreover, the A. phagocytophilum-like 1 and 2 strains should be considered in the differential diagnosis of caprine and ovine anaplasmosis. Further investigations should be conducted to provide additional epidemiological information about A. phagocytophilum and A. phagocytophilum-like variants in animals and ticks.

Some aspects on tick species in Mongolia and their potential role in the transmission of equine piroplasms, Anaplasma phagocytophilum and Borrelia burgdorferi L

Ticks are cosmopolitan vectors of numerous diseases, and detection of various pathogens in ticks can help to assess their distribution. In the current study, 528 adult ticks were collected from grazing animals or the ground in ten different Mongolian provinces. Dermacentor nuttalli constituted 76.1% of them and was found in all ecozones except the eastern desert. Dermacentor marginatus (8.3%), Dermacentor silvarum (1.1%) and Ixodes persulcatus (3.0%) were found in the northern forest areas and Hyalomma asiaticum (11.4%) only in the southern (semi-)desert. Of these, 359 ticks were subjected to DNA extraction and PCR was carried out to detect various pathogens. Anaplasma spp. was found in D. marginatus and D. nuttalli (2.5% positive each), including flagged specimen and identified as Anaplasma phagocytophilum. Borrelia spp. were found in 2.5% of the ticks (mostly in I. persulcatus) and identified as Borrelia garinii. Babesia spp. (40%) identified as Babesia caballi were detected in all five tick species including flagged Dermacentor spp. and I. persulcatus, and 3.5% of the ticks (all species except D. silvarum) were positive for Theileria spp. identified as Theileria equi. The piroplasms were found in all provinces. Tick-borne encephalitis virus was not detected. The results highlight the high risk of equine piroplasmosis in Mongolia, which is a concern for both the nomadic population who rely on horses for transport and for conservation of Przewalski's horses in Mongolia. In addition, zoonotic agents such as the avian B. garinii and A. phagocytophilum were also detected, outlining a high risk for exposed humans.

Anaplasma phagocytophilum in sheep and goats in central and southeastern China

BACKGROUND

Anaplasma phagocytophilum is wide spread throughout the world and impacts both human and animal health. Several distinct ecological clusters and ecotypes of the agent have been established on the basis of various genetic loci. However, information on the genetic variability of A. phagocytophilum isolates in China represents a gap in knowledge. The objective of this study was to determine the prevalence and genetic characterization of A. phagocytophilum in small ruminants in central and southeastern China.

METHODS

The presence of A. phagocytophilum was determined in 421 blood samples collected from small ruminants by PCR. Positive samples were genetically characterized based on 16S rRNA and groEL genes. Statistical analyses were conducted to identify ecotypes of A. phagocytophilum strains, to assess their host range and zoonotic potential.

RESULTS

Out of 421 sampled small ruminants, 106 (25.2%) were positive for A. phagocytophilum. The positive rate was higher in sheep (35.1%, 40/114) than in goats (26.4%, 66/307) (P < 0.05). Sequence analyses revealed that the isolates identified in this study were placed on two separate clades, indicating that two 16S rRNA variants of A. phagocytophilum were circulating in small ruminants in China. However, analysis using obtained groEL sequences in this study formed one cluster, which was separate from other known ecotypes reported in Europe. In addition, a novel Anaplasma sp. was identified and closely related to an isolate previously reported in Hyalomma asiaticum, which clustered independently from all recognized Anaplasma species.

CONCLUSIONS

A molecular survey of A. phagocytophilum was conducted in sheep and goats from ten provinces in central and southeastern China. Two 16S rRNA variants and a new ecotype of A. phagocytophilum were identified in small ruminants in China. Moreover, a potential novel Anaplasma species was reported in goats. Our findings provide additional information on the complexity of A. phagocytophilum in terms of genetic diversity in China.

Evaluation of different nested PCRs for detection of Anaplasma phagocytophilum in ruminants and ticks

BACKGROUND

Anaplasma phagocytophilum is a causative agent of granulocytic anaplasmosis in mammals, which has a broad geographical distribution and a high degree of clinical diversity. Currently, numerous PCR assays have been developed and used for the detection of A. phagocytophilum in various specimens. However, their performance varies. The aim of this study was to evaluate the performance of five nested PCR assays by detection of 363 ruminant and tick samples, and to select the most appropriate methods for the sensitive detection of A. phagocytophilum in environmental or clinical samples.

RESULTS

Positive PCR results for A. phagocytophilum were obtained in 75 (20.7%), 42 (11.6%) and 19 (5.2%) specimens with primer sets EC (EC9/EC12a and SSAP2f/SSAP2r), EE (EE1/EE2 and EE3/EE4) and ge (ge3a/ge10r, ge9f/ge2), respectively. The amplification of template DNA with the primer set MSP (MAP4AP5/MSP4AP3, msp4f/msp4r) could not be obtained in both ruminants and ticks, and a low specificity of the EL primers [EL(569)F/EL(1193)R, EL(569)F/EL(1142)R] in tick samples was observed. Our results revealed that the nested PCR with primer set EC complementary to the 16S rRNA gene was the most sensitive assay for detection of A. phagocytophilum in ruminant and tick specimens. A. phagocytophilum was detected in 47 (35.1%) sheep, 12 (10.4%) cattle, and 17 (14.9%) ticks. Two A. phagocytophilum genotypes were identified, that varied between sheep and cattle in sample collection sites.

CONCLUSIONS

This report provides more valuable information for the diagnosis and management of granulocytic anaplasmosis in China.

Diversity of ankA and msp4 genes of Anaplasma phagocytophilum in Slovenia

Granulocytic anaplasmosis is a tick transmitted emerging disease in Europe and worldwide. The agent, Anaplasma phagocytophilum is transmitted by ticks of the genus Ixodes and causes infections in humans and domestic animals. The analysis of different target genes showed that in nature several genetic variants of A. phagocytophilum were present. The purpose of our study was to genetically characterize A. phagocytophilum strains from eight humans, 16 dogs, 12 wild boars, one bear and 18 tick pools from Slovenia. Therefore, the ankA and msp4 genes of A. phagocytophilum were chosen. The same genetic ankA and msp4 variant of A. phagocytophilum was detected in humans, wild boar and a part of the pooled ticks indicating that it circulates in a zoonotic cycle between wild boar and ticks. In dogs, three ankA variants of A. phagocytophilum were detected. One of them was identical to the one that was found in humans. In contrast, all dogs harboured the same msp4 variant as humans and wild boar. In ticks, numerous ankA and msp4 variants were present.

Wild boars as hosts of human-pathogenic Anaplasma phagocytophilum variants

To investigate the potential of wild boars to host Anaplasma phagocytophilum, we analyzed bacterial 16S rRNA and ank genes. DNA sequencing identified several A. phagocytophilum variants, including a predominance of strains known to cause human disease. Boars are thus hosts for A. phagocytophilum, notably, strains associated with human granulocytic anaplasmosis.

Gene expression profile suggests that pigs (Sus scrofa) are susceptible to Anaplasma phagocytophilum but control infection

Background

Anaplasma phagocytophilum infects a wide variety of hosts and causes granulocytic anaplasmosis in humans, horses and dogs and tick-borne fever in ruminants. Infection with A. phagocytophilum results in the modification of host gene expression and immune response. The objective of this research was to characterize gene expression in pigs (Sus scrofa) naturally and experimentally infected with A. phagocytophilum trying to identify mechanisms that help to explain low infection prevalence in this species.

Results

For gene expression analysis in naturally infected pigs, microarray hybridization was used. The expression of differentially expressed immune response genes was analyzed by real-time RT-PCR in naturally and experimentally infected pigs. Results suggested that A. phagocytophilum infection affected cytoskeleton rearrangement and increased both innate and adaptive immune responses by up regulation of interleukin 1 receptor accessory protein-like 1 (IL1RAPL1), T-cell receptor alpha chain (TCR-alpha), thrombospondin 4 (TSP-4) and Gap junction protein alpha 1 (GJA1) genes. Higher serum levels of IL-1 beta, IL-8 and TNF-alpha in infected pigs when compared to controls supported data obtained at the mRNA level.

Conclusions

These results suggested that pigs are susceptible to A. phagocytophilum but control infection, particularly through activation of innate immune responses, phagocytosis and autophagy. This fact may account for the low infection prevalence detected in pigs in some regions and thus their low or no impact as a reservoir host for this pathogen. These results advanced our understanding of the molecular mechanisms at the host-pathogen interface and suggested a role for newly reported genes in the protection of pigs against A. phagocytophilum.

Anaplasma phagocytophilum in ticks in Slovenia

Ticks act as vectors of many pathogens of domestic animals and humans. Anaplasma phagocytophilum in Europe is transmitted by the ixodid tick vector Ixodes ricinus. A. phagocytophilum causes a disease with diverse clinical signs in various hosts. A great genetic diversity of the groESL operon of A. phagocytophilum has been found in ticks elsewhere. In Slovenia, the variety of the groESL operon was conducted only on deer samples. In this study, the prevalence of infected ticks was estimated and the diversity of A. phagocytophilum was evaluated. On 8 locations in Slovenia, 1924 and 5049 (6973) I. ricinus ticks were collected from vegetation in the years 2005 and 2006, respectively. All three feeding stages of the tick's life cycle were examined. The prevalence of ticks infected with A. phagocytophilum in the year 2005 and in the year 2006 was 0.31% and 0.63%, respectively, and it did not differ considerably between locations. The similarity among the sequences of groESL ranged from 95.6% to 99.8%. They clustered in two genetic lineages along with A. phagocytophilum from Slovenian deer. One sequence formed a separate cluster. According to our study, the prevalence of A. phagocytophilum in ticks is comparable to the findings in other studies in Europe, and it does not vary considerably between locations and tick stages. According to groESL operon analysis, two genetic lineages have been confirmed and one proposed. Further studies on other genes would be useful to obtain more information on genetic diversity of A. phagocytophilum in ticks in Slovenia.