Zoonotic Virus Seroprevalence among Bank Voles, Poland, 2002-2010.

Bank voles in Poland are reservoirs of zoonotic viruses. To determine seroprevalence of hantavirus, arenavirus, and cowpox virus and factors affecting seroprevalence, we screened for antibodies against these viruses over 9 years. Cowpox virus was most prevalent and affected by extrinsic and intrinsic factors. Long-term and multisite surveillance is crucial.

Rickettsia helvetica and R. monacensis infections in immature Ixodes ricinus ticks derived from sylvatic passerine birds in west-central Poland.

The aim of this study was to assess the importance of forest passerine birds in spreading ixodid ticks infected with rickettsiae of spotted fever group (SFG) in sylvatic habitats in western Poland. In total, 834 immature Ixodes ricinus ticks were found on 64 birds of 11 species which were captured during the tick-questing season between May and September of 2006. Ground-foraging passerines hosted most of the ticks compared with arboreal species, and therefore, only the former group was included into a detailed analysis. Significant predominance of larvae over nymphs was observed (581 vs. 253, respectively). Blackbirds and song thrushes hosted 82 % (n = 681) of the ticks collected from all infested passerines. The overall prevalence range of SF rickettsiae (including Rickettsia helvetica and Rickettsia monacensis) in bird-derived ticks was 10.5-26.9 %, exceeding that in questing ticks, and in ticks feeding on rodents and deer reported earlier from the same study area. This high prevalence of infection in immature I. ricinus ticks feeding on passerine birds strongly implies that they are involved in the enzootic maintenance of spotted fever group rickettsiae in the tick vector populations occurring in sylvatic habitats.

Detection of Borrelia burgdorferi sensu lato and spotted fever group rickettsiae in hard ticks (Acari, Ixodidae) parasitizing bats in Poland.

A total of 491 Ixodes vespertilionis and 8 Ixodes ricinus collected from bats and cave walls in southern Poland between 2010 and 2012 were examined by the polymerase chain reaction for tick-transmitted pathogens. PCR analysis for Borrelia burgdorferi s.l., Rickettsia spp., and Anaplasma phagocytophilum yielded negative results for all I. vespertilionis. DNA of Rickettsia helvetica was detected in three specimens of I. ricinus attached to Rhinolophus hipposideros or Myotis myotis, while Borrelia garinii was found in one tick parasitizing Myotis daubentonii. These pathogens were recorded for the first time in hard ticks that parasitized bats.

Kampinos National Park: a risk area for spotted fever group rickettsioses, central Poland?

Ixodid ticks are important vectors of a variety of bacterial and protozoan pathogens which cause infections in humans. In this study, altogether 1041 questing Ixodes ricinus (n = 305) and Dermacentor reticulatus ticks (n = 736), sympatrically occurring in Kampinos National Park (KPN), central-east Poland, were analyzed by PCR for Rickettsia species. Overall, the pathogen prevalence in ticks was 27.5 % for I. ricinus and 42.8 % for D. reticulatus. Sequencing analysis showed that the first tick species was exclusively infected with R. helvetica, whereas the latter was infected with R. raoultii. These organism may pose a threat for populations exposed to ticks. Preliminary results of a serosurvey of 74 KPN employees, inhabitants and visitors from the same area showed a 31.1 % total seroprevalence against SFG rickettsiae compared to 13.3 % seropositive blood donors of the control group. Risk factors significantly associated with IgG seropositivity were: occupational exposure to ticks (p = 0.002), frequency of tick bites (p = 0.02) and male gender (p = 0.005). Seropositive and seronegative individuals occupationally exposed to ticks did not differ significantly with respect to age and years of employment.

Detection and quantification of Anaplasma phagocytophilum and Babesia spp. in Ixodes ricinus ticks from urban and rural environment, northern Poland, by real-time polymerase chain reaction.

Anaplasma phagocytophilum and Babesia spp. are emerging tick-borne pathogens which can threaten human health. A duplex real-time PCR and qPCRs with primers and probes targeting 97 and 116 bp fragments of 16S rRNA and 18S rRNA genes, respectively, were used for qualitative and quantitative detection of both pathogens in Ixodes ricinus ticks. Altogether 1875 ticks (1084 adults and 791 nymphs) were collected from rural and urban habitats in northern Poland. Of them, at least 0.9% were found to be infected with A. phagocytophilum while 2.5% with Babesia spp. A comparison of the infection rates by the tick stage, the type of area, the collection site, habitats of different tick density and by the month of collection was done. The prevalence of pathogens was significantly lower in nymphs than in adult ticks (p = 0.02) and in rural areas than in urban areas (p = 0.007). Four different 16S rRNA gene variants of A. phagocytophilum were determine, however none of them showed 100% identity with compared sequences isolated from human patients. The dominant Babesia species was B. venatorum. Results of qPCRs with circular and linearized forms of plasmids used as the standards showed significant difference in the pathogen loads (p = 0.001). The copy numbers of A. phagocytophilum and Babesia spp. estimated from the linear plasmids were 28.7 and 5.1 times lower, respectively, when compared with their circular forms, and were accepted as more reliable. The average number of copies of 16S rRNA gene of A. phagocytophilum in the positive I. ricinus samples were 3.39 × 10(5) ± 6.09 × 10(5). The mean copy number of 18S rRNA gene of Babesia spp. was ~2.55 × 10(5) ± 1.04 × 10(6). We confirmed the presence of A. phagocytophilum and Babesia spp. in I. ricinus in both rural and urban environments. The determined low infection rates suggests, however, that the risk for local population and tourists to acquire infection is also low. Moreover, we confirmed recent findings that serious overestimation by circular plasmid DNA makes it less suitable as a standard and that the linear standards should be recommended for qPCR.

Prevalence of tick-borne encephalitis virus (TBEV) RNA in Dermacentor reticulatus ticks from natural and urban environment, Poland.

Tick-borne encephalitis virus (TBEV) (Flaviviridae, Flavivirus) is an arthropod-borne virus, an etiologic agent of tick-borne encephalitis (TBE), a human infection involving the central nervous system. The disease is endemic in a large region in Eurasia, where it is transmitted mainly by Ixodes ricinus and Ixodes persulcatus ticks. It is known that also Dermacentor reticulatus is involved in circulation of TBEV. However, the current knowledge of D. reticulatus importance in TBE epidemiology is still insufficient. A total of 471 adult D. reticulatus ticks were collected by flagging vegetation in the Bialowieza Primeval Forest, Biebrza National Park, Masurian Landscape Park (North-Eastern Poland) and in the city of Warsaw in the years 2007-2010. All collected ticks were examined individually for the presence of RNA of TBEV using nested RT-PCR assay. Positive results were noted in all investigated localities with the infection rate ranging from 0.99 to 12.5 % with a total mean of 2.12 %. The difference in the percentage of infective males and females was not statistically significant.

Cutaneous myiasis caused by Dermatobia hominis (Diptera: Oestridae) in a Polish traveller to South America - a case report.

Myiasis, an infestation caused by dipteran larvae, commonly known as maggots, is one of the most common parasitic skin disorders in the tropical regions. Authors report a case of cutaneous myiasis caused by Dermatobia hominis (Diptera: Oestridae) in a Polish traveller returning from a self-organized trip to South America. Species biology, prophylaxis, and medical implications of this tropical parasitosis are discussed.

Seroprevalence of Toxoplasma gondii among Sylvatic Rodents in Poland.

Toxoplasma gondii is an intracellular Apicomplexan parasite with a broad range of intermediate hosts, including humans and rodents. Rodents are considered to be reservoirs of infection for their predators, including cats, felids, pigs, and wild boars. We conducted a multi-site, long-term study on T. gondii in northeastern Poland. The study aimed to monitor the seroprevalence of T. gondii in the four abundant vole species found in the region (Myodes glareolus, Microtus arvalis, Microtus agrestis, and Alexandromys oeconomus) and to assess the influence of both extrinsic (year of study and study site) and intrinsic (host sex and host age) factors on seroprevalence. A bespoke enzyme-linked immunosorbent assay was used to detect antibodies against T. gondii. We examined 577 rodent individuals and detected T. gondii antibodies in the sera of all four rodent species with an overall seroprevalence of 5.5% [4.2-7.3] (3.6% [2.6-4.9] for M. glareolus and 20% [12-30.9] for M. arvalis, M. agrestis, and A. oeconomus). Seroprevalence in bank voles varied significantly between host age and sex. Seroprevalence increased with host age and was higher in females than males. These results contribute to our understanding of the distribution and abundance of T. gondii in voles in Poland and confirm that T. gondii also circulates in M. glareolus and M. arvalis, M. agrestis and A. oeconomus. Therefore, they may potentially play a role as reservoirs of this parasite in the sylvatic environment.

Dengue antibodies in Polish travellers returning from the tropics. Evaluation of serological tests.

Dengue is a viral disease caused by an RNA virus of the genus Flavivirus, family Flaviviridae, occurring as four serotypes (DEN-1, -2, -3, -4). It is transmitted to humans by the Aedes mosquitoes, mainly A. aegypti. The occurrence of dengue is strictly related with their preferred breeding areas. Dengue endemic regions are inhabited by some 2.5 billion people. 50-100 million cases of dengue fever and up to 1 million cases of dengue haemorrhagic fever are noted worldwide in more than 100 countries every year. The aim of the reported examinations was to diagnose dengue virus infections in returning travellers. In the years 2006-2009 serological tests were performed in 753 persons. In the diagnostics we used ELISA to find IgM and/or IgG class of antibodies against dengue virus, rapid immunochromatographic (cassette) test, NS1 viral antigen detection by ELISA, and virus RNA detection by RT-PCR method. IgM or IgG class antibodies, and both classes simultaneously, were detected in 19.8% of the examined cases. The greatest number of infections came from India and the Far East, next from South and Central America, and the smallest number from Africa. Sixteen patients with diagnosed dengue, including three cases of dengue haemorrhagic fever, were hospitalized.

Seroprevalence of Tick-Borne Encephalitis Virus in Three Species of Voles (Microtus spp.) in Poland.

Rodents play a role as reservoir hosts for tick-borne encephalitis virus (TBEV). We trapped 77 voles of the genus Microtus and tested their blood using an enzyme-linked immunosorbent assay for the presence of antibodies against TBEV. We detected TBEV antibodies in three adult individuals (4%). Voles might play a role in the circulation of TBEV.

Zoonotic Viruses in Three Species of Voles from Poland.

Rodents are known to be reservoir hosts for a plethora of zoonotic viruses and therefore play a significant role in the dissemination of these pathogens. We trapped three vole species (Microtus arvalis, Alexandromys oeconomus and Microtus agrestis) in northeastern Poland, all of which are widely distributed species in Europe. Using immunofluorescence assays, we assessed serum samples for the presence of antibodies to hantaviruses, arenaviruses and cowpox viruses (CPXV). We detected antibodies against CPXV and Puumala hantavirus (PUUV), the overall seroprevalence of combined viral infections being 18.2% [10.5-29.3] and mostly attributed to CPXV. We detected only one PUUV/TULV cross-reaction in Microtus arvalis (1.3% [0.1-7.9]), but found similar levels of antibodies against CPXV in all three vole species. There were no significant differences in seroprevalence of CPXV among host species and age categories, nor between the sexes. These results contribute to our understanding of the distribution and abundance of CPXV in voles in Europe, and confirm that CPXV circulates also in Microtus and Alexandromys voles in northeastern Poland.

[A study on the occurrence of West Nile virus in mosquitoes (Diptera: Culicidae) on the selected areas in Poland]. / Badania nad wystepowaniem wirusa goraczki Zachodniego Nilu u komarów (Diptera: Culicidae) na wybranych terenach Polski.

West Nile virus (WNV), the etiologic agent of West Nile Fever (WNF), an emerging infectious disease that lately has been rapidly extending its range of occurrence from Africa to Middle East, and to Asia and Southern Europe. In Europe, cases of isolating WNV from mosquitoes representing four genera have been reported from Romania, Portugal, France, southern Russia and what is the most important, from Poland's neighbouring countries as the Czech Republic, Slovakia and southern Ukraine. These data, as well as human and equine cases in the Czech Republic and Belarus, support hypothesis that WNV has already been present also in Poland, the more so, specific antibodies were detected in the sera of birds collected at the Kampinos and Bialowieza Primeval Forests and in human from the vicinity of Bialystok. Mosquitoes were collected in 2004-2009 at indoor and outdoor collection sites in districts: Kujawsko-Pomorskie, Mazowieckie, Podlaskie and Warminsko-Mazurskie. In total 15400 female mosquitoes were collected in the cow sheds and overwintering in the cellars, and from human bait and CO2 traps. Mosquitoes were sorted by the collecting site, species and sex, and placed in pools of not in more than 50 specimens in special mixture of phenol and chaotropic salts and frozen in -20 degrees C. Altogether, 15400 females were examined. Total RNA were extracted according to protocol of A&A Biotechnology. RT reaction was performed with random primers and 217-nucleotide fragment from the NS5 coding sequence was amplified by heminested PCR. PCR products were analysed on 1.5% agarose gel. The predominant species was Culex pipiens, accounting for over 42% of total insects collection. All obtained results were negative. Further investigations are needed.

Selected arboviral diseases imported to Poland - current state of knowledge and perspectives for research.

INTRODUCTION: Arthropod-borne viruses are important causes of human morbidity worldwide. However, the available literatur and the epidemiological data concerning the importation to Poland of globally emerging arboviral infections, such as DENV, CHIKV, WNV, or ZIKV, are scarce. Only few seroepidemiologic studies concerning WNV in animals or humans in Poland have been published. OBJECTIVE: The aim of this review paper is to summarize and present the current state of knowledge and the perspectives for research concerning the importation and the risk posed by the introduction to Poland of the four above-mentioned arboviral diseases. CURRENT STATE OF KNOWLEDGE: Climate change may facilitate the northward expansion of both the vectors for diseases previously unseen in Europe, as well as of the viruses themselves, resulting in autochthonous cases of diseases previously exclusively imported. Little is known about the importation of arboviral diseases to Poland because of the frequently asymptomatic or self-limiting course of the disease, lack of epidemiologic studies or effective disease reporting, as well as inadequate access to diagnostic methods. CONCLUSIONS: Further epidemiologic studies in Polish travellers are necessary in order to prevent importation or introduction of the above-mentioned viruses, and to act against potential problems related to blood transfusion or organ transplantation from infected donors.

The role of particular ticks developmental stages in the circulation of tick-borne pathogens in Central Europe. 5. Borreliaceae

The developmental cycles of all B. burgdorferi s.l. genospecies present typical, main pattern described in the 90thies. The simple scheme might be modified according to the biology of species and hosts preference. Central European genospecies of B. burgdorferi s.l. can be associated with four groups of hosts playing the role of animal reservoirs. The group 1 contains genospecies associated with rodents as primary animal reservoir ­ B. afzelii, B. garinii, B. burgdorferi sensu stricto, strains B. bavariensis (B. garinii OspA serotype 4). The group 2 involves B. valaisiana and most of B. garinii strains, associated with birds. The group 3 involves B. spielmanii, the reservoir hosts are Gliridae, and hedgehogs. The group 4 includes B. lusitaniae, the hosts are lizards. B. miyamotoi enzootic cycle seems to be similar to B. burgdorferi complex, however, differs by the transovarial transmission possibility. The divisions are not extreme; in the hosts group, infected with appropriate Borrelia genospecies, very often are found the specimens infected with other genospecies.

Prevalence of different Rickettsia spp. in Ixodes ricinus and Dermacentor reticulatus ticks (Acari: Ixodidae) in north-eastern Poland.

In two surveys conducted in April and May 2013, a total of 1148 unfed ticks belonging to two species, Ixodes ricinus and Dermacentor reticulatus, were collected by flagging lower vegetation in 15 different localities throughout the Bialowieza Primeval Forest (Podlaskie voivodship; north-eastern Poland) and in its buffer zone. In order to establish their infection rate with Rickettsia spp. individual adult ticks and pooled nymphs were tested by real-time PCR targeting the gltA gene. For the further identification of rickettsial species, positive samples were subjected for nested and semi-nested PCR targeting ompA and 16S rRNA genes, respectively, followed by sequencing analysis. Rickettsial DNA was detected in at least 279 ticks (minimum infection rate [MIR], 23.9%), including 52 nymphal and adult I. ricinus (MIR 8.6%) and 222 adult D. reticulatus (41%). Three species of SFG rickettsiae were identified: Rickettsia helvetica and 'Candidatus R. mendelii' in I. ricinus and R. raoultii in D. reticulatus and I. ricinus. Moreover, unidentified Rickettsia spp. which showed 99.4% identity, among others, with the uncultured Rickettsia sp. isolated from Cicadella viridis leafhopper, Rickettsia endosymbiont of Lasioglossum semilucens bee and R. bellii, were detected in I. ricinus, while Rickettsia sp. 98.3-98.4% homologous to Rickettsia secondary endosymbionts of Curculio spp. weevils was found in D. reticulatus. These results confirm the diversity of rickettsiae occurring in Poland. Further studies are needed to expand the knowledge on the species spectrum, prevalence and epidemiology of SFG rickettsiae in the country.

The role of particular ticks developmental stages in the circulation of tick-borne pathogens in Central Europe. 6. Babesia.

In the Central European conditions, three species of Babesia have epidemiological significance as human pathogens ­ Babesia divergens, B. microti and B. venatorum. Tick Ixodes ricinus is considered as their main vector, wild mammals as the animal reservoir. The zoonotic cycles of small and large Babesia differ in details. Due to the lack of transovarial mode transmission in small species B. microti, the circulation goes mainly between immature ticks and vertebrate hosts; pathogen circulates primarily in the cycle: infected rodent → the tick larva → the nymph → the mammal reservoir →the larva of the tick. The tick stages able to effectively infect human are nymphs and adult females, males do not participate in the follow transmission. For large Babesia ­ B. divergens and B. venatorum, the transovarial and transstadial transmission enable the presence of the agent in adult ticks, moreover, that larvae and nymphs feed on not-susceptible hosts. The tick stages able to effectively infect cattle and other ruminants are adult females. Resuming, pathogen circulates primarily in the cycle the ruminant host ­ adult female tick ­ the larva ­ the nymph ­ adult female of the next generation ­ the ruminant. Due to the compound developmental transmission has place after the outflow of a tick began feeding.

Seroprevalence of TBEV in bank voles from Poland-a long-term approach.

Rodents are known to play a significant role as reservoir hosts for TBEV. During three sequential expeditions at 4-year intervals to three ecologically similar study sites in NE Poland, we trapped bank voles (Myodes glareolus) and then tested their blood for the presence of specific antiviral antibodies to TBEV. The strongest effects on seroprevalence were the extrinsic factors, site of capture of voles and year of sampling. Seroprevalence increased markedly with increasing host age, and our analysis revealed significant interactions among these three factors. Seroprevalence did not differ between the sexes. Therefore, based on the seroprevalence results, the dynamics of TBEV infection differ significantly in time, between local sub-populations of bank voles and with increasing host age. To fully understand the circulation of the virus among these reservoir hosts and in the environment, long-term monitoring is required and should employ a multi-site approach, such as the one adopted in the current study.

The role of particular tick developmental stages in the circulation of tick-borne pathogens affecting humans in Central Europe. 2. Tick-borne encephalitis virus.

Hard-bodied ticks transmit various pathogens, such as Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Rickettsia spp., Babesia spp., and carry numerous other microorganisms with an unknown pathogenic potential. Among them, tick-borne encephalitis virus has great importance. In Central European conditions all developmental stages of ticks participate in the zoonotic cycle of the TBE virus. According to pathogen and tick biology, the roles of larvae, nymphs and adults are different. Larvae and nymphs of Ixodes ricinus ticks are responsible for circulation in rodents and medium sized mammals; adults transfer the infection to ruminants and to next generations via transovarial transmission. All active developmental stages of I. ricinus can play role of the bridge vector, transmitting the infection to humans apart males which don't feed. The late summer peak of human infectivity is caused by the summer peak of I. ricinus nymphs' activity. The Dermacentor reticulatus tick attacks humans infrequently, but does participate in the circulation of the virus in the zoonotic foci; larvae and nymphs of the D. reticulatus ticks are responsible for circulation in rodents, mainly Microtinae, while adults transmit the infection to ruminants.

The transstadial persistence of tick-borne encephalitis virus in Dermacentor reticulatus ticks in natural conditions.

There are a number of reports regarding natural infection of Dermacentor reticulatus ticks with TBE virus; however, the transmission mode of TBE virus in this tick population has not been investigated. This study was conducted in Bialowieza Primeval Forest, east Poland. Forty fully engorged nymphs of D. reticulatus were sampled from root voles (Microtus oeconomus). Ticks were kept until molting. All ticks were screened for the presence of TBE virus by nested RT-PCR. Three adult ticks were positive for infection with TBE virus. The present study for the first time demonstrates the possibility of transstadial mode of TBEV transmission in D. reticulatus ticks.