Aleksandar Potkonjak

Prof. Dr. Aleksandar Potkonjak

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Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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21 December 2019 in Parasites & Vectors
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Journal Article
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IMIoana Adriana Matei
Ioana Adriana Matei
Agustin Estrada-PeñaAgustin Estrada-Peña
Agustin Estrada-Peña
Sally Jane CutlerSally Jane Cutler
Sally Jane Cutler
MVMuriel Vayssier-Taussat
Muriel Vayssier-Taussat
LCLucía Varela Castro
Lucía Varela Castro
Andrei Daniel MihalcaAndrei Daniel Mihalca
Andrei Daniel Mihalca
Anaplasma phagocytophilum is the agent of tick-borne fever, equine, canine and human granulocytic anaplasmosis. The common route of A. phagocytophilum transmission is through a tick bite, the main vector in Europe being Ixodes ricinus. Despite the apparently ubiquitous presence of the pathogen A. phagocytophilum in ticks and various wild and domestic animals from Europe, up to date published clinical cases of human granulocytic anaplasmosis (HGA) remain rare compared to the worldwide status. It is unclear if this reflects the epidemiological dynamics of the human infection in Europe or if the disease is underdiagnosed or underreported. Epidemiologic studies in Europe have suggested an increased occupational risk of infection for forestry workers, hunters, veterinarians, and farmers with a tick-bite history and living in endemic areas. Although the overall genetic diversity of A. phagocytophilum in Europe is higher than in the USA, the strains responsible for the human infections are related on both continents. However, the study of the genetic variability and assessment of the difference of pathogenicity and infectivity between strains to various hosts has been insufficiently explored to date. Most of the European HGA cases presented as a mild infection, common clinical signs being pyrexia, headache, myalgia and arthralgia. The diagnosis of HGA in the USA was recommended to be based on clinical signs and the patient’s history and later confirmed using specialized laboratory tests. However, in Europe since the majority of cases are presenting as mild infection, laboratory tests may be performed before the treatment in order to avoid antibiotic overuse. The drug of choice for HGA is doxycycline and because of potential for serious complication the treatment should be instituted on clinical suspicion alone.

1 February 2017 in Molecular and Cellular Probes
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Journal Article
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Sally Jane CutlerSally Jane Cutler
Sally Jane Cutler
Eva Ružić-SabljićEva Ružić-Sabljić
Eva Ružić-Sabljić
APAleksandar Potkonjak
Aleksandar Potkonjak
Lyme borreliosis (or Lyme disease) has become a virtual household term to the exclusion of other forgotten, emerging or re-emerging borreliae. We review current knowledge regarding these other borreliae, exploring their ecology, epidemiology and pathological potential, for example, for the newly described B. mayonii. These bacteria range from tick-borne, relapsing fever-inducing strains detected in some soft ticks, such as B. mvumii, to those from bat ticks resembling B. turicatae. Some of these emerging pathogens remain unnamed, such as the borrelial strains found in South African penguins and some African cattle ticks. Others, such as B. microti and unnamed Iranian strains, have not been recognised through a lack of discriminatory diagnostic methods. Technical improvements in phylogenetic methods have allowed the differentiation of B. merionesi from other borrelial species that co-circulate in the same region. Furthermore, we discuss members that challenge the existing dogma that Lyme disease-inducing strains are transmitted by hard ticks, whilst the relapsing fever-inducing spirochaetes are transmitted by soft ticks. Controversially, the genus has now been split with Lyme disease-associated members being transferred to Borreliella, whilst the relapsing fever species retain the Borrelia genus name. It took some 60 years for the correlation with clinical presentations now known as Lyme borreliosis to be attributed to their spirochaetal cause. Many of the borreliae discussed here are currently considered exotic curiosities, whilst others, such as B. miyamotoi, are emerging as significant causes of morbidity. To elucidate their role as potential pathogenic agents, we first need to recognise their presence through suitable diagnostic approaches.

4 December 2018 in International Journal of Health Geographics
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Journal Article
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Agustin Estrada-PeñaAgustin Estrada-Peña
Agustin Estrada-Peña
Sally Jane CutlerSally Jane Cutler
Sally Jane Cutler
APAleksandar Potkonjak
Aleksandar Potkonjak
MVMuriel Vassier-Tussaut
Muriel Vassier-Tussaut
WBWim Van Bortel
Wim Van Bortel
Andrei Daniel MihalcaAndrei Daniel Mihalca
Andrei Daniel Mihalca
The bacteria of the group Borrelia burgdorferi s.l. are the etiological agents of Lyme borreliosis in humans, transmitted by bites of ticks. Improvement of control measures requires a solid framework of the environmental traits driving its prevalence in ticks. We updated a previous meta-analysis of the reported prevalence of Borrelia burgdorferi s.l. in questing nymphs of Ixodes ricinus with a literature search from January 2010–June 2017. This resulted in 195 new papers providing the prevalence of Bb for 926 geo-referenced records. Previously obtained data (878 records, years 2000–2010) were appended for modelling. The complete dataset contains data from 82,004 questing nymphs, resulting in 558 records of B. afzelii, 404 of B. burgdorferi s.s. (only 80 after the year 2010), 552 of B. garinii, 78 of B. lusitaniae, 61 of B. spielmanii, and 373 of B. valaisiana. We associated the records with explicit coordinates to environmental conditions and to a categorical definition of European landscapes (LANMAP2) looking for a precise definition of the environmental niche of the most reported species of the pathogen, using models based on different classification methods. The most commonly reported species are B. afzelii, B. garinii and B. valaisiana largely overlapping across Europe. Prevalence in ticks is associated with portions of the environmental niche. Highest prevalence occurs in areas of 280°–290° (Kelvin) of mean annual temperature experiencing a small amplitude, steady spring slope, together with high mean values and a moderate spring rise of vegetation vigor. Low prevalence occurs in sites with low and a noteworthy annual amplitude of temperature and the Normalized Difference Vegetation Index (colder areas with abrupt annual changes of vegetation). Models based on support vector machines provided a correct classification rate of the habitat and prevalence of 89.5%. These results confirm the association of prevalence of the three most commonly reported species of B. burgdorferi s.l. in Europe to parts of the environmental niche and provide a statistically tractable framework for analyzing trends under scenarios of climate change.

2 May 2019 in Eurosurveillance
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Journal Article
Open access
Sally Jane CutlerSally Jane Cutler
Sally Jane Cutler
MVMuriel Vayssier-Taussat
Muriel Vayssier-Taussat
Agustin Estrada-PeñaAgustin Estrada-Peña
Agustin Estrada-Peña
APAleksandar Potkonjak
Aleksandar Potkonjak
Andrei Daniel MihalcaAndrei Daniel Mihalca
Andrei Daniel Mihalca
HZHervé Zeller
Hervé Zeller
Background: Borrelia miyamotoi clusters phylogenetically among relapsing fever borreliae, but is transmitted by hard ticks. Recent recognition as a human pathogen has intensified research into its ecology and pathogenic potential. Aims: We aimed to provide a timely critical integrative evaluation of our knowledge on B. miyamotoi, to assess its public health relevance and guide future research. Methods: This narrative review used peer-reviewed literature in English from January 1994 to December 2018. Results: Borrelia miyamotoi occurs in the world’s northern hemisphere where it co-circulates with B. burgdorferi sensu lato, which causes Lyme disease. The two borreliae have overlapping vertebrate and tick hosts. While ticks serve as vectors for both species, they are also reservoirs for B. miyamotoi. Three B. miyamotoi genotypes are described, but further diversity is being recognised. The lack of sufficient cultivable isolates and vertebrate models compromise investigation of human infection and its consequences. Our understanding mainly originates from limited case series. In these, human infections mostly present as influenza-like illness, with relapsing fever in sporadic cases and neurological disease reported in immunocompromised patients. Unspecific clinical presentation, also occasionally resulting from Lyme- or other co-infections, complicates diagnosis, likely contributing to under-reporting. Diagnostics mainly employ PCR and serology. Borrelia miyamotoi infections are treated with antimicrobials according to regimes used for Lyme disease. Conclusions: With co-infection of tick-borne pathogens being commonplace, diagnostic improvements remain important. Developing in vivo models might allow more insight into human pathogenesis. Continued ecological and human case studies are key to better epidemiological understanding, guiding intervention strategies.

1 February 2016 in Ticks and Tick-borne Diseases
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Journal Article
Closed access
APAleksandar Potkonjak
Aleksandar Potkonjak
RGRicardo Gutiérrez
Ricardo Gutiérrez
SSSara Savić
Sara Savić
VVVuk Vračar
Vuk Vračar
YNYaarit Nachum-Biala
Yaarit Nachum-Biala
Shimon HarrusShimon Harrus
Shimon Harrus

2 December 2014 in Frontiers in Public Health
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Journal Article
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SSSara Savić
Sara Savić
BVBranka Vidiä
Branka Vidiä
ZGZivoslav Grgiä
Zivoslav Grgiä
APAleksandar Potkonjak
Aleksandar Potkonjak
LSLjubica Spasojevic
Ljubica Spasojevic
Vector borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowdays, in intercontinetal countries, there is a struggle with emerging diseases which have found their way to appear through vectors. Vector borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector borne infectious diseases and disease outbreaks. It could affect the range and popultion of pathogens, host and vectors, transmission season, etc. Reliable surveilance for diseases that are most likely to emerge is required. Canine vector borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, erlichiosis, leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fudamental role at primeraly prevention and then treatment of vector borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases. During a four year period, from 2009-2013, a total number of 551 dog samples were analysed for vector borne diseases (borreliosis, babesiosis, erlichiosis, anaplasmosis, dirofilariosis and leishmaniasis) in routine laboratory work. The analysis were done by serological tests – ELISA for borreliosis, dirofilariosis and leishmaniasis, modified Knott test for dirofilariosis and blood smear for babesiosis, erlichiosis and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on avarege more then half of the samples brought to the la