First described case of human granulocytic anaplasmosis in a patient in Eastern Austria

Human Granulocytic Anaplasmosis-A Systematic Review of Published Cases

Anaplasma phagocytophilum is an emerging, Gram-negative, obligate intracellular pathogen that is transmitted by a tick vector. Human infection ranges from asymptomatic to severe disease that can present with pancytopenia, multiorgan failure, and death. The aim of this systematic review is to analyze case reports and case series reported over the last two decades in peer-reviewed journals indexed in the Medline/PubMed database according to the PRISMA guidelines. We found 110 unique patients from 88 case reports and series. The most common mode of transmission was tick bite (60.9%), followed by blood transfusion (8.2%). Infection was acquired by blood transfusion in nearly half (42%) of the immunocompromised patients. Most patients reported fever (90%), followed by constitutional (59%) and gastrointestinal symptoms (56%). Rash was present in 17% of patients, much higher than in previous studies. Thrombocytopenia was the most common laboratory abnormality (76%) followed by elevated aspartate aminotransferase (AST) (46%). The diagnosis was most commonly established using whole-blood polymerase chain reaction (PCR) in 76% of patients. Coinfection rate was 9.1% and Borrelia burgdorferi was most commonly isolated in seven patients (6.4%). Doxycycline was used to treat 70% of patients but was only used as an empiric treatment in one-third of patients (33.6%). The overall mortality rate was 5.7%, and one patient died from trauma unrelated to HGA. The mortality rates among immunocompetent and immunocompromised patients were 4.2% (n = 4/95) and 18.2% (n = 2/11), respectively. Four of the six patients who died (66.6%) received appropriate antibiotic therapy. Among these, doxycycline was delayed by more than 48 h in two patients.

Evaluation of Disease Causality of Rare Ixodes ricinus-Borne Infections in Europe

In Europe, Ixodes ricinus ticks transmit pathogens such as Borrelia burgdorferi sensu lato and tick-borne encephalitis virus (TBEV). In addition, there is evidence for transmission to humans from I. ricinus of Anaplasma phagocytophilum, Babesia divergens, Babesia microti, Babesia venatorum, Borrelia miyamotoi, Neoehrlichia mikurensis, Rickettsia helvetica and Rickettsia monacensis. However, whether infection with these potential tick-borne pathogens results in human disease has not been fully demonstrated for all of these tick-borne microorganisms. To evaluate the available evidence for a causative relation between infection and disease, the current study analyses European case reports published from 2008 to 2018, supplemented with information derived from epidemiological and experimental studies. The evidence for human disease causality in Europe found in this review appeared to be strongest for A. phagocytophilum and B. divergens. Nonetheless, some knowledge gaps still exist. Importantly, comprehensive evidence for pathogenicity is lacking for the remaining tick-borne microorganisms. Such evidence could be gathered best through prospective studies, for example, studies enrolling patients with a fever after a tick bite, the development of specific new serological tools, isolation of these microorganisms from ticks and patients and propagation in vitro, and through experimental studies.

Approaches for Reverse Line Blot-Based Detection of Microbial Pathogens in Ixodes ricinus Ticks Collected in Austria and Impact of the Chosen Method

Ticks transmit a large number of pathogens capable of causing human disease. In this study, the PCR-reverse line blot (RLB) method was used to screen for pathogens in a total of 554 Ixodes ricinus ticks collected from all provinces of Austria. These pathogens belong to the genera Borrelia, Rickettsiae, Anaplasma/Ehrlichia (including "Candidatus Neoehrlichia"), Babesia, and Coxiella The pathogens with the highest detected prevalence were spirochetes of the Borrelia burgdorferisensu lato complex, in 142 ticks (25.6%). Borrelia afzelii (80/142) was the most frequently detected species, followed by Borrelia burgdorferisensu stricto (38/142) and Borrelia valaisiana (36/142). Borrelia garinii/Borrelia bavariensis, Borrelia lusitaniae, and Borrelia spielmanii were found in 28 ticks, 5 ticks, and 1 tick, respectively. Rickettsia spp. were detected in 93 ticks (16.8%): R. helvetica (39/93), R. raoultii (38/93), R. monacensis (2/93), and R. slovaca (1/93). Thirteen Rickettsia samples remain uncharacterized. "Candidatus Neoehrlichia mikurensis," Babesia spp. (B. venatorum, B. divergens, B. microti), and Anaplasma phagocytophilum were found in 4.5%, 2.7%, and 0.7%, respectively. Coxiella burnetii was not detected. Multiple microorganisms were detected in 40 ticks (7.2%), and the cooccurrence of Babesia spp. and "Candidatus Neoehrlichia mikurensis" showed a significant positive correlation. We also compared different PCR-RLBs for detection of Borrelia burgdorferisensu lato and Rickettsia spp. and showed that different detection approaches provide highly diverse results, indicating that analysis of environmental samples remains challenging.IMPORTANCE This study determined the wide spectrum of tick-borne bacterial and protozoal pathogens that can be encountered in Austria. Surveillance of (putative) pathogenic microorganisms occurring in the environment is of medical importance, especially when those agents can be transmitted by ticks and cause disease. The observation of significant coinfections of certain microorganisms in field-collected ticks is an initial step to an improved understanding of microbial interactions in ticks. In addition, we show that variations in molecular detection methods, such as in primer pairs and target genes, can considerably influence the final results. For instance, detection of certain genospecies of borreliae may be better or worse by one method or the other, a fact of great importance for future screening studies.

Direct detection of Anaplasma phagocytophilum by polymerase chain reaction followed by electrospray ionization mass spectrometry from human blood

Bacterial pathogens not detectable via commercial blood culture assays represent an important challenge for infectious disease physicians, in particular if clinical symptoms of the illness are non-specific. In this report, Anaplasma phagocytophilum was detected directly in a peripheral blood sample from a febrile patient reporting a tick bite. This was done using a commercial system based on PCR followed by electrospray ionization mass spectrometry (ESI-MS). The diagnosis of a human granulocytic anaplasmosis infection was established using this diagnostic methodology for the first time. Human granulocytic anaplasmosis is a neglected zoonotic disease in Europe. Its seroprevalence is similar in North America and Europe, but in contrast to the USA, it is rarely diagnosed in the old world. PCR followed by ESI-MS is a novel, complex, but highly promising diagnostic methodology for the rapid assessment of rare or exotic pathogens, including intracellular bacteria.

Human granulocytic anaplasmosis acquired in Connecticut, USA, diagnosed in Vienna, Austria, 2015

Human granulocytic anaplasmosis (HGA) is caused by Anaplasma phagocytophilum, an intracellular pathogen transmitted by hard ticks. We report a patient who had acquired the infection in Connecticut, USA, and was diagnosed in Vienna, Austria, using PCR methods. Imported HGA from the United States to Austria is a rare event.

Comparison of clinical and laboratory characteristics of patients fulfilling criteria for proven and probable human granulocytic anaplasmosis

To assess the value of clinical definitions for human granulocytic anaplasmosis (HGA) epidemiological, clinical and laboratory findings in 50 adult patients with proven HGA (Anaplasma phagocytophilum isolated from blood, and/or positive PCR result, and/or seroconversion or ≥4-fold change in serum IFA antibody titres to A. phagocytophilum) and 46 patients with probable HGA (demonstration of serum antibodies to A. phagocytophilum in titres ≥1:256) were compared. Patients with proven HGA were older (55 versus 43.5 years; p = 0.001), were more often treated with doxycycline (31/50, 62% versus 11/46, 23.9%; p < 0.001), more frequently reported chills (40/50, 80% versus 17/46, 36.9%; p < 0.001), myalgia (37/50, 74% versus 21/46, 45.7%; p = 0.005) and cough (10/50, 20% versus 2/46, 4.4%; p = 0.02), and had more often abnormal laboratory findings such as thrombocytopenia (45/50, 90% versus 22/46, 47.8%; p < 0.001), abnormal liver function test results (45/50, 87% versus 22/46, 47.8%; p < 0.001), leukopenia (38/50, 76% versus 21/46, 45.7%; p = 0.002) and elevated serum CRP concentration (48/50, 96% versus 31/46, 67.4%; p < 0.001). The dissimilarities imply that in some patients fulfilling criteria for probable HGA the signs and symptoms most likely are not the result of a recent infection with A. phagocytophilum and indicate that clinical definitions used in the present study have a distinctive value.

Ixodes ricinus and Its Transmitted Pathogens in Urban and Peri-Urban Areas in Europe: New Hazards and Relevance for Public Health

Tick-borne diseases represent major public and animal health issues worldwide. Ixodes ricinus, primarily associated with deciduous and mixed forests, is the principal vector of causative agents of viral, bacterial, and protozoan zoonotic diseases in Europe. Recently, abundant tick populations have been observed in European urban green areas, which are of public health relevance due to the exposure of humans and domesticated animals to potentially infected ticks. In urban habitats, small and medium-sized mammals, birds, companion animals (dogs and cats), and larger mammals (roe deer and wild boar) play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Presence of ticks infected with tick-borne encephalitis virus and high prevalence of ticks infected with Borrelia burgdorferi s.l., causing Lyme borreliosis, have been reported from urbanized areas in Europe. Emerging pathogens, including bacteria of the order Rickettsiales (Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis," Rickettsia helvetica, and R. monacensis), Borrelia miyamotoi, and protozoans (Babesia divergens, B. venatorum, and B. microti) have also been detected in urban tick populations. Understanding the ecology of ticks and their associations with hosts in a European urbanized environment is crucial to quantify parameters necessary for risk pre-assessment and identification of public health strategies for control and prevention of tick-borne diseases.

Endoparasites of the fallow deer (Dama dama) of the Antheringer Au in Salzburg, Austria

Although the annual harvest of fallow deer increased markedly in Austria in the past two decades, only little is known about the parasites of fallow deer in Austria. To add current faunistic knowledge on the endoparasites of fallow deer in the country, viscera from six adult males and one male fawn from the game preserve Antheringer Au, Salzburg, were examined in 2009-2010 using standard techniques, and spleen samples were screened for DNA of tick-borne pathogens (polymerase chain reaction). Infections with sarcocysts (Sarcocystis spp.) and gastrointestinal nematodes (range: 379-1,294 worms) were demonstrated in all deer; four and three bucks had Dictyocaulus eckerti (range: two to seven worms) and Varestrongylus sagittatus lungworms, respectively; Fasciola hepatica (9 and 18 flukes) were isolated from the liver of two bucks, and DNA of Babesia capreoli was isolated from the spleen of one buck. In addition, Eimeria sordida oocysts were identified in the faeces of the fawn that harboured also one Setaria sp., presumably Setaria altaica, in its mesentery. Fifteen species (morphs for the ostertagians) of gastrointestinal nematodes were identified: Ostertagia leptospicularis, Ostertagia drozdzi/Skrjabinagia ryjikovi, Spiculopteragia asymmetrica, Spiculopteragia boehmi/Rinadia mathevossiani, Trichostrongylus askivali, Trichostrongylus capricola, Cooperia pectinata, Nematodirus battus, Nematodirus roscidus, Capillaria bovis, Oesophagostomum sikae, Oesophagostomum venulosum and Trichuris globulosa. Two and four bucks had high individual burdens of more than 500 and more than 1,000 worms, respectively. As the nematode counts of the five bucks harvested during the mating season were associated with unusual high faecal egg counts, and four of the bucks had Dictyocaulus lungworms in addition, these findings may suggest a reduced resistance to parasites related with high levels of androgens and experience of stress during rut.

Ixodes ricinus and Its Transmitted Pathogens in Urban and Peri-Urban Areas in Europe: New Hazards and Relevance for Public Health

Tick-borne diseases represent major public and animal health issues worldwide. Ixodes ricinus, primarily associated with deciduous and mixed forests, is the principal vector of causative agents of viral, bacterial, and protozoan zoonotic diseases in Europe. Recently, abundant tick populations have been observed in European urban green areas, which are of public health relevance due to the exposure of humans and domesticated animals to potentially infected ticks. In urban habitats, small and medium-sized mammals, birds, companion animals (dogs and cats), and larger mammals (roe deer and wild boar) play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Presence of ticks infected with tick-borne encephalitis virus and high prevalence of ticks infected with Borrelia burgdorferi s.l., causing Lyme borreliosis, have been reported from urbanized areas in Europe. Emerging pathogens, including bacteria of the order Rickettsiales (Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis," Rickettsia helvetica, and R. monacensis), Borrelia miyamotoi, and protozoans (Babesia divergens, B. venatorum, and B. microti) have also been detected in urban tick populations. Understanding the ecology of ticks and their associations with hosts in a European urbanized environment is crucial to quantify parameters necessary for risk pre-assessment and identification of public health strategies for control and prevention of tick-borne diseases.

Detection of Candidatus Neoehrlichia mikurensis, Borrelia burgdorferi sensu lato genospecies and Anaplasma phagocytophilum in a tick population from Austria

Candidatus Neoehrlichia mikurensis DNA was discovered in Ixodes ricinus ticks in 1999 and is referred to as an emerging human pathogen since its first detection in patients with febrile illness reported in 2010. In recent years, Ca. Neoehrlichia mikurensis has been detected in ticks from several European, Asian, and African countries. However, no epidemiological data exist for Austria, which is a highly endemic region for tick-transmitted diseases. To assess the geographic spread and prevalence of Ca. Neoehrlichia mikurensis sympatric with other tick-transmitted pathogens, we analysed 518 I. ricinus ticks collected in 2002 and 2003 in Graz, Austria. The prevalence of Ca. Neoehrlichia mikurensis was 4.2%, that of Borrelia burgdorferi sensu lato 25.7%, and that of Anaplasma phagocytophilum 1%. Coinfections with Ca. Neoehrlichia mikurensis and B. burgdorferi sensu lato were found in 2.3% of all ticks. Thus, the results show a relatively high prevalence of Ca. Neoehrlichia mikurensis in Austrian ticks suggesting a high probability for the occurrence of undiagnosed human infections in Austria.