Prevalence of Anaplasma phagocytophilum in humans in Belgium for the period 2013-2016

Anaplasma phagocytophilum in Ticks Blood-Feeding on Migratory Birds in Sweden

Migratory birds play a dual role as potential reservoirs of tick-borne pathogens, and potential dispersers of pathogen-containing ticks during their migratory journeys. Ixodes ricinus, a prevalent tick species in Northern and Western Europe, serves as a primary vector for Anaplasma phagocytophilum-a bacterium with implications for human and animal health. There is limited information available regarding A. phagocytophilum in birds. Our investigation focused on A. phagocytophilum prevalence in ticks collected from migratory birds in southeastern Sweden. The identification of ticks involved both molecular analyses for species determination and morphological classification to ascertain the developmental stage. The presence of A. phagocytophilum was determined using real-time PCR. Of the 1115 ticks analyzed from 4601 birds, 0.9% (n = 10), including I. ricinus and Ixodes frontalis, tested positive for A. phagocytophilum. Notably, common blackbirds (Turdus merula) yielded the highest number of A. phagocytophilum-infected ticks. The findings suggest that A. phagocytophilum is present in a small proportion of ticks infesting migratory birds in southeastern Sweden. Consequently, the role of birds as hosts for ticks infected with A. phagocytophilum appears to be low, suggesting that birds seem to play a minor indirect role in the geographic dispersal of A. phagocytophilum.

Antibiotic resistance in tick-borne bacteria: A One Health approach perspective

The emergence and re-emergence of tick-borne bacteria (TBB) as a public health problem raises the uncertainty of antibiotic resistance in these pathogens, which could be dispersed to other pathogens. The impact of global warming has led to the emergence of pathogenic TBB in areas where they were not previously present and is another risk that must be taken into account under the One Health guides. This review aimed to analyze the existing information regarding antibiotic-resistant TBB and antibiotic-resistance genes (ARG) present in the tick microbiome, considering the potential to be transmitted to pathogenic microorganisms. Several Ehrlichia species have been reported to exhibit natural resistance to fluoroquinolones and typhus group Rickettsiae are naturally susceptible to erythromycin. TBB have a lower risk of acquiring ARG due to their natural habitat, but there is still a probability of acquiring them; furthermore, studies of these pathogens are limited. Pathogenic and commensal bacteria coexist within the tick microbiome along with ARGs for antibiotic deactivation, cellular protection, and efflux pumps; these ARGs confer resistance to antibiotics such as aminoglycosides, beta-lactamase, diaminopyrimidines, fluoroquinolones, glycopeptides, sulfonamides, and tetracyclines. Although with low probability, TBB can be a reservoir of ARGs.

Detection of Anaplasma phagocytophilum in fetal and placental tissue of bovine abortions and perinatal mortalities

BACKGROUND

Anaplasma phagocytophilum is a tick-borne zoonotic bacterium that is the aetiologic pathogen of tick-borne fever (TBF) in ruminants. In clinical bovine cases of TBF, abortion and stillbirth may be observed. However, in this regard, the pathophysiology of TBF has not yet been completely elucidated, and no clear guidelines to diagnose A. phagocytophilum-related abortions and perinatal mortalities (APM) are available.

METHODS

This exploratory study aimed to investigate the presence of A. phagocytophilum in bovine cases of APM and determine whether placental or fetal spleen tissue has the greatest sensitivity for A. phagocytophilum identification. The placenta and fetal spleen of 150 late-term bovine APM cases were analysed using real-time PCR to detect A. phagocytophilum.

RESULTS

A total of 2.7% of sampled placentas were positive for A. phagocytophilum, while none of the fetal spleen samples was.

LIMITATIONS

No histopathology to detect associated lesions was performed. Consequently, no evidence of causality between the detection of A. phagocytophilum and APM events could be achieved.

CONCLUSION

The detection of A. phagocytophilum suggests a potential role of this pathogen in bovine APM, and placental tissue seems to be the most suitable tissue for its identification.

Worldwide meta-analysis on Anaplasma phagocytophilum infections in animal reservoirs: Prevalence, distribution and reservoir diversity

A wide range of vertebrate species are competent reservoirs of Anaplasma phagocytophilum, where the pathogen is maintained in the enzootic cycle and transmitted to humans through activities of tick vectors. An insight into the role and diversity of these reservoirs is vital in understanding the epidemiology of this pathogen. Here, we determined the prevalence, distribution and reservoir diversity of A. phagocytophilum using a systematic review and meta-analysis. Data pooling was performed by the random-effects model, heterogeneity was assessed by the Cochran's Q-test and publication bias by Egger's regression test. Eighty-nine studies from 33 countries across 5 continents revealed A. phagocytophilum pooled prevalence of 15.18% (95% CI: 11.64, 19.57). Continental estimates varied significantly (p < 0.0001), with a range of 2.88% (95% CI: 0.25, 26.20) in South America to 19.91% (95% CI: 13.57, 28.24) in Europe. Country-based estimates ranged between 2.93% (95% CI: 1.17, 7.16) in Slovakia and 71.58% (95% CI: 25.91, 94.77) in Norway. Studies on A. phagocytophilum were concentrated in Europe (51.69%; 46/89) by continent and the USA (22.47%; 20/89) by country. Prevalence in wildlife (17.64%; 95% CI: 12.21-28.59) was significantly higher (p < 0.001) than that among domestic animals (10.68%; 95% CI: 6.61-16.83). Diverse species of wildlife, domestic animals and birds were infected by A. phagocytophilum. To curtail the public health, veterinary and economic consequences of A. phagocytophilum infections, we recommend an all-inclusive epidemiological approach that targets the human, animal and environmental components of the disease.

No molecular detection of tick-borne pathogens in the blood of patients with erythema migrans in Belgium

Background

A number of tick-borne pathogens circulate in the Belgian tick population in addition to the causative agent of Lyme borreliosis. However, so far, only a few patients with tick-borne diseases other than Lyme borreliosis have been reported in Belgium. The aim of this study was to investigate the occurrence of other human tick-borne infections in Belgium and their possible clinical manifestation.

Methods

Patients with fever (> 37.5 °C) after a tick bite or those with erythema migrans (EM) were included in the study. EDTA-blood samples were screened for the presence of DNA from Borrelia burgdorferi sensu lato, Borrelia miyamotoi, Anaplasma phagocytophilum, Neoehrlichia mikurensis, spotted fever group rickettsiae (genus Rickettsia), Babesia spp., Bartonella spp., Spiroplasma ixodetis and tick-borne encephalitis virus, using multiplex PCR methods. A questionnaire on, among others, demographics and clinical symptoms, was also filled in.

Results

Over a period of 3 years, 119 patients with EM and 14 patients with fever after a recent tick bite were enrolled in the study. Three samples initially tested positive for N. mikurensis by quantitative PCR (qPCR), but the results could not be confirmed by other PCR methods, and repetition of the DNA extraction procedure and qPCR test was not successful. The qPCR test results for the other tick-borne pathogens were negative.

Conclusions

In general, only a few patients with fever after a tick bite could be identified. Although no tick-borne pathogens were detected, their occurrence cannot be excluded based on the limited number of patients and the limitations inherent to current methodologies. This study underscores the possibility of false-positive PCR results and the necessity for the development of multiple independent tools for the sensitive and specific detection of emerging tick-borne pathogens.

Graphical Abstract