The effect of infectious agents on the prevalence of allergies.

PURPOSE: The role of infectious agents in allergy development is ambivalent. On one hand, there are reports of an association between a previous infection (especially a viral respiratory tract infection) and developing hypersensitivity to inhaled allergens, which in turn may increase the risk of developing allergic reactions. On the other hand, there are reports emphasizing a protective effect of a number of infectious agents against allergy development. The aim the study was to find possible associations between a past infectious or parasitic disease and an allergic condition. MATERIAL AND METHODS: The study population was a group of 18,648 subjects. The study, which was a part of the project: 'Implementation of a System for the Prevention and Early Detection of Allergic Diseases in Poland', was conducted in 9 selected regions of Poland and used the ECRHS and ISAAC questionnaires adapted for Europe. The following statistical tools were used: Pearson's chi-squared test, Fisher's exact test, and logistic regression. RESULTS: This research was an attempt to clear association between a history of measles or viral hepatitis and the likelihood of developing asthma, especially in males (χ2 = 5.29; p<0.05). Past parasitic disease showed a clear association with a suspected allergic rhinitis in various groups of patients (differing both in terms of sex and age). CONCLUSIONS: A history of some forms of either infectious or parasitic diseases has a measurable effect on the risk of developing allergies.

Rickettsiales Occurrence and Co-occurrence in Ixodes ricinus Ticks in Natural and Urban Areas.

Bacteria of Rickettsiaceae and Anaplasmataceae families include disease agents spread by Ixodes ricinus ticks, the most common tick vector in Europe. The aim of the study was to compare the prevalence and co-infection prevalence of particular tick-transmitted Rickettsiales members: Rickettsia spp. (further referred as Rs), Anaplasma phagocytophilum (Ap), and "Candidatus Neoehrlichia mikurensis" (CNM) in I. ricinus ticks in two types of areas, different in terms of human impact: natural and urban. Using additional data, we aimed at investigating co-occurrence of these Rickettsiales with Borreliella spp. A total of 4189 tick specimens, 2363 from the urban area (Warsaw park and forests) and 1826 from the natural area (forests and park in the vicinity of National Parks), were tested for the presence of Rickettsiales DNA by PCRs. The prevalence of selected Rickettsiales was twice higher in urban than natural areas (13.2% vs. 6.9%, respectively). In total ticks, the prevalence of Rs, Ap, and CNM was 6.5%, 5.3%, and 3.6% in urban areas vs. 4.4%, 1.1%, and 2.1% in natural areas, respectively. Co-infections of Rickettsiales were also more prevalent in urban areas (2.6% vs. 0.3%, respectively). The most common Rs was R. helvetica; also R. monacensis and novel "Candidatus Rickettsia mendelii" were detected. Positive association between Ap and CNM infections was discovered. Rickettsiales bacteria occurrence was not associated with Borreliella occurrence, but co-infections with these two groups were more common in ticks in urban areas. In conclusion, three groups of Rickettsiales constituted the important part of the tick pathogen community in Poland, especially in the urbanized central Poland (Mazovia). In the Warsaw agglomeration, there is a greater risk of encountering the I. ricinus tick infected with Rickettsiales and co-infected with Lyme spirochaetes, in comparison to natural areas. This finding raises the question whether cities might in fact be the hot spots for TBDs.

Ticks and the city - are there any differences between city parks and natural forests in terms of tick abundance and prevalence of spirochaetes?

BACKGROUND: Ixodes ricinus ticks are commonly encountered in either natural or urban areas, contributing to Lyme disease agents Borreliella [(Borrelia burgdorferi (sensu lato)] spp. and Borrelia miyamotoi enzootic cycles in cities. It is an actual problem whether urbanization affects pathogen circulation and therefore risk of infection. The aim of the study was to evaluate main tick-borne disease risk factors in natural, endemic areas of north-east (NE) Poland (Bialowieza) and urban areas of central Poland (Warsaw), measuring tick abundance/density, prevalence of infection with spirochaetes and diversity of these pathogens in spring-early summer and late summer-autumn periods between 2012 and 2015. METHODS: Questing I. ricinus ticks were collected from three urban sites in Warsaw, central Poland and three natural sites in Bialowieza, NE Poland. A total of 2993 ticks were analyzed for the presence of Borreliella spp. and/or Borrelia miyamotoi DNA by PCR. Tick abundance was analyzed by General Linear Models (GLM). Prevalence and distribution of spirochaetes was analyzed by Maximum Likelihood techniques based on log-linear analysis of contingency tables (HILOGLINEAR). Species typing and molecular phylogenetic analysis based on the sequenced flaB marker were carried out. RESULTS: Overall 4617 I. ricinus ticks were collected (2258 nymphs and 2359 adults). We report well established population of ticks in urban areas (10.1 ± 0.9 ticks/100 m2), as in endemic natural areas with higher mean tick abundance (16.5 ± 1.5 ticks/100 m2). Tick densities were the highest in spring-early summer in both types of areas. We observed no effect of the type of area on Borreliella spp. and B. miyamotoi presence in ticks, resulting in similar prevalence of spirochaetes in urban and natural areas [10.9% (95% CI: 9.7-12.2%) vs 12.4% (95% CI: 10.1-15.1%), respectively]. Prevalence of spirochaetes was significantly higher in the summer-autumn period than in the spring-early summer [15.0% (95% CI: 12.8-17.5%) vs 10.4% (95% CI: 9.2-11.6%), respectively]. We have detected six species of bacteria present in both types of areas, with different frequencies: dominance of B. afzelii (69.3%) in urban and B. garinii (48.1%) in natural areas. Although we observed higher tick densities in forests than in maintained parks, the prevalence of spirochaetes was significantly higher in the latter [9.8% (95% CI: 8.6-11.0%) vs 17.5% (95% CI: 14.4-20.5%)]. CONCLUSIONS: Surprisingly, a similar risk of infection with Borreliella spp. and/or B. miyamotoi was discovered in highly- and low-transformed areas. We suggest that the awareness of presence of these disease agents in cities should be raised.

Borrelia miyamotoi: A human tick-borne relapsing fever spirochete in Europe and its potential impact on public health.

Borrelia miyamotoi is a tick-borne bacterium which has only recently been identified in Europe as a human pathogen causing relapsing fever and little is known about its local impact on human health. There are three types of B. miyamotoi: Asian (Siberian), European, and American. B. miyamotoi is transmitted by the same Ixodes ricinus-persulcatus species complex, which also transmits B. burgdorferi s.l., the Lyme borreliosis group. Both Borrelia groups are mostly maintained in natural rodent populations. The aim of this review is to summarize the available literature on B. miyamotoi, with the focus of attention falling on Europe, as well as to describe its presence in ticks, reservoir hosts, and humans and discuss its potential impact on public health.

Long-term spatiotemporal stability and dynamic changes in helminth infracommunities of bank voles (Myodes glareolus) in NE Poland.

Parasites are considered to be an important selective force in host evolution but ecological studies of host-parasite systems are usually short-term providing only snap-shots of what may be dynamic systems. We have conducted four surveys of helminths of bank voles at three ecologically similar woodland sites in NE Poland, spaced over a period of 11 years, to assess the relative importance of temporal and spatial effects on helminth infracommunities. Some measures of infracommunity structure maintained relative stability: the rank order of prevalence and abundance of Heligmosomum mixtum, Heligmosomoides glareoli and Mastophorus muris changed little between the four surveys. Other measures changed markedly: dynamic changes were evident in Syphacia petrusewiczi which declined to local extinction, while the capillariid Aonchotheca annulosa first appeared in 2002 and then increased in prevalence and abundance over the remaining three surveys. Some species are therefore dynamic and both introductions and extinctions can be expected in ecological time. At higher taxonomic levels and for derived measures, year and host-age effects and their interactions with site are important. Our surveys emphasize that the site of capture is the major determinant of the species contributing to helminth community structure, providing some predictability in these systems.

Clinical and molecular features of one case of human infection with Anaplasma phagocytophilum from Podlaskie Province in eastern Poland.

The article focuses on the clinical and laboratory diagnosis of human granulocytic anaplasmosis (HGA) caused by Anaplasma phagocytophilum infection in one of 28 patients (3.6%; n=1/28 tested samples) with early Lyme borreliosis. The clinical and laboratory results of a 42-year-old patient fulfilled criteria of confirm anaplasmosis and suggest an acute stage of illness. The described case provides strong presumptive evidence that infection in this patient was acquired with a pathogenic strain of A. phagocytophilum through a tick bite. A positive DNA with PCR for A. phagocytophilum infection was sequenced and analyzed phylogenetically. Physicians should consider the possibility of anaplasmosis in patients with early Lyme borreliosis, and A. phagocytophilum should be considered as a differential diagnosis in all patients from an endemic region of potential high risk factors for tick-borne diseases.

First report of two asymptomatic cases of human infection with Babesia microti (Franca, 1910) in Poland.

Human infection by Babesia microti has been recognized as an emerging zoonosis with important public health implications worldwide. In Europe the reported cases of human babesiosis have been attributed mostly to B. divergens infection, with only sporadic cases of the disease caused by B. microti or B. venatorum. This study, based on molecular methods (PCR, R-T PCR, DNA sequencing and phylogenetic analysis), reveals for the first time in Poland, asymptomatic infection with . microti in immunocompetent healthy individuals working in forest ecosystems. Of the 58 professional foresters examined, two (3.4%) were identified as B. microti-positive by specific PCR. The results of this study also provide strong evidence that in eastern Poland, where tick-borne diseases (TBDs) are endemic, there is a potential risk of acquiring human babesiosis due to zoonotic B. microti parasites commonly found in rodents and I. ricinus ticks. The potential public health importance of this finding is discussed.

Asymptomatic "Candidatus Neoehrlichia mikurensis" infections in immunocompetent humans.

In Europe, human infections with "Candidatus Neoehrlichia mikurensis" have mainly been restricted to immunocompromised patients. We report here the first cases of asymptomatic "Ca. Neoehrlichia mikurensis" infection in immunocompetent humans (5/316 [1.6%] were infected). Due to the potential threats of infections with "Ca. Neoehrlichia mikurensis" in healthy persons to the safety of the blood supply, further study of this phenomenon is required.

Occurrence of intestinal microsporidia in immunodeficient patients in Poland.

Microsporidial infections may be asymptomatic in immunocompetent hosts, but can be severe and disseminated in HIV/AIDS patients, children, the elderly, or in immunocompromised individuals, including those with primary or medically-induced immunodeficiencies. 209 faecal samples were collected from 80 clinical patients, with or without abdominal symptoms, and tested for the presence of the parasites. Microsporidia were found in 10 of the 80 patients (12.5%) using trichrom staining of faecal smears and/or PCR. Encephalitozoon intestinalis and 1 unidentified species were identified in 2 of the 32 children with primary immunodeficiencies (6%), presenting with diarrhoea, including one co-infection with Cryptosporidium meleagridis. In the group of patients with medically-induced immunosuppression (transplant recipients), 8 of the 48 patients (17%) were tested positive for microsporidia. Thus, these pathogens should be taken into account when the other etiological agents cannot be found in diarrheic patients with PIDs or undergoing immunosuppressive treatment before or after transplantation. This article presents the results of the first epidemiological study on the occurrence and prevalence of microsporidia in patients with primary and secondary immunodeficiency in Poland.

Long-term spatiotemporal stability and dynamic changes in the haemoparasite community of bank voles (Myodes glareolus) in NE Poland.

Long-term field studies on parasite communities are rare but provide a powerful insight into the ecological and evolutionary processes shaping host-parasite interactions. The aim of our study was to identify the principal factors regulating long-term trends in the haemoparasite communities of bank voles, and to this end, we sampled three semi-isolated populations of bank voles (n = 880) in 1999, 2002, 2006 and 2010 in the Mazury lake district region of NE Poland. Overall, 90.8 % of the bank voles harboured at least one of the species of haemoparasites studied. Whilst overall prevalence (all species combined) did not vary significantly between the surveys, different temporal changes were detected among voles in each of the three sites. In voles from Urwitalt, prevalence increased consistently with successive surveys, whereas in Talty, the peak years were 2002 and 2006, and in Pilchy, prevalence oscillated without a clear pattern. Across the study, bank voles harboured a mean of 1.75 ± 0.034 haemoparasite species, and species richness remained stable with no significant between-year fluctuations or trends. However, each of the five constituent species/genera showed a different pattern of spatio-temporal changes. The overall prevalence of Babesia microti was 4.9 %, but this varied significantly between years peaking in 2006 and declining again by 2010. For Bartonella spp., overall prevalence was 38.7 %, and this varied with year of study, but the temporal pattern of changes differed among the three sites. The overall prevalence of Haemobartonella (Mycoplasma) was 68.3 % with an increase in prevalence with year of study in all three sites. Hepatozoon erhardovae had an overall prevalence of 46.8 % but showed a marked reduction with each successive year of the study, and this was consistent in all three sites. The overall prevalence of Trypanosoma evotomys was 15.4 % varying significantly between sites, but showing temporal stability. While overall prevalence of all haemoparasites combined and species richness remained stable over the period of study, among the five haemoparasites, the pattern of spatiotemporal changes in prevalence and abundance of infections differed depending on parasite species. For some genera, host age was shown to play an important role, but a significant effect of host sex was found only for Haemobartonella spp.

Rickettsiaceae and Anaplasmataceae infections in Ixodes ricinus ticks from urban and natural forested areas of Poland.

BACKGROUND: Ixodes ricinus is a major vector for a range of microbial pathogens and the most prevalent and widely distributed tick species on the European continent, occurring in both natural and urban habitats. Nevertheless, little is known about the relative density of ticks in these two ecologically distinct habitats and the diversity of tick-borne pathogens that they carry. METHODS: We compared densities of questing I. ricinus nymphs and adults in urban and natural habitats in Central and Northeastern Poland, assessed the prevalence and rate of co-infection with A. phagocytophilum, Rickettsia, Ehrlichia and 'Ca. Neoehrlichia spp.' in ticks, and compared the diversity of tick-borne pathogens using molecular assays (PCR). RESULTS: Of the 1325 adults and nymphs, 6.2% were infected with at least one pathogen, with 4.4%, 1.7% and less than 0.5% being positive for the DNA of Rickettsia spp., A. phagocytophilum, Ehrlichia spp. and Ca. N. mikurensis, respectively. Although tick abundance was higher in natural habitats, the prevalence of the majority of pathogens was higher in urban forested areas. CONCLUSION: We conclude that: (i) zoonotic genetic variants of A. phagocytophilum are widely distributed in the Polish tick population, (ii) although the diversity of tick borne pathogens was higher in natural habitats, zoonotic species/strains were detected only in urban forests, (iii) and we provide the first description of Ca. N. mikurensis infections in ticks in Poland.

Recombination, diversity and allele sharing of infectivity proteins between Bartonella species from rodents.

The alpha-Proteobacterium Bartonella is a common parasite of voles and mice, giving rise to short-lived (4 weeks to 2 months) infections. Here, we report high sequence diversity in genes of the VirB/VirD type IV secretion system (T4SS), amongst Bartonella from natural rodent populations in NE Poland. The VirB5 protein is predicted to consist of three conserved alpha helices separated by loops of variable length which include numerous indels. The C-terminal domain includes repeat stretches of KEK residues, reflecting underlying homopolymeric stretches of adenine residues. A total of 16 variants of VirB5, associated with host identity, but not bacterial taxon, were identified from 22 Bartonella isolates. One was clearly a recombinant from two others, another included an insertion of two KEK repeats. The virB5 gene appears to evolve via both mutation and recombination, as well as slippage mediated insertion/deletion events. The recombinational units are thought to be relatively short, as there was no evidence of linkage disequilibrium between virB5 and the bepA locus only 5.5 kb distant. The diversity of virB5 is assumed to be related to immunological role of this protein in Bartonella infections; diversity of virB5 may assist persistence of Bartonella in the rodent population, despite the relatively short (3-4 weeks) duration of individual infections. It is clear from the distribution of virB5 and bepA alleles that recombination within and between clades is widespread, and frequently crosses the boundaries of conventionally recognised Bartonella species.

Babesia spp. infections transmitted through blood transfusion.

Babesiosis in humans is caused by infection with various species of Babesia (Apicomplexa, Piroplasmida), mainly transmitted by an arthropod vector--Ixodes spp. ticks. This review will focus on blood transfusion as another mode of Babesia transmission, especially in endemic areas, as well as the impact of human babesiosis on transfusion medicine.

Recombination within and between species of the alpha proteobacterium Bartonella infecting rodents.

Bartonella infections from wild mice and voles (Apodemus flavicollis, Mi. oeconomus, Microtus arvalis and Myodes glareolus) were sampled from a forest and old-field habitats of eastern Poland; a complex network of Bartonella isolates, referrable to B. taylorii, B. grahamii, B. birtlesii and B. doshiae, was identified by the sequencing of a gltA fragment, comparable to previous studies of Bartonella diversity in rodents. Nested clade analysis showed that isolates could be assigned to zero- and one-step clades which correlated with host identity and were probably the result of clonal expansion; however, sequencing of other housekeeping genes (rpoB, ribC, ftsZ, groEl) and the 16S RNA gene revealed a more complex situation with clear evidence of numerous recombinant events in which one or both Bartonella parents could be identified. Recombination within gltA was found to have generated two distinct variant clades, one a hybrid between B. taylorii and B. doshiae, the other between B. taylorii and B. grahamii. These recombinant events characterised the differences between the two-step and higher clades within the total nested cladogram, involved all four species of Bartonella identified in this work and appear to have played a dominant role in the evolution of Bartonella diversity. It is clear, therefore, that housekeeping gene phylogenies are not robust indicators of Bartonella diversity, especially when only a single gene (gltA or 16S RNA) is used. Bartonella clades infecting Microtus were most frequently involved in recombination and were most frequently tip clades within the cladogram. The role of Microtus in influencing the frequency of Bartonella recombination remains unknown.

Co-infection with Borrelia species and other tick-borne pathogens in humans: two cases from Poland.

Co-infection with Borrelia species and Anaplasma phagocytophilum or Babesia spp. was assessed in a retrospective study of tick-exposed individuals from southeastern Poland. The co-infection rate of these pathogens was found to be rather low (Borrelia spp./Anaplasma phagocytophilum--4.2%, 1/24; Borrelia spp./Babesia spp.--4.2%, 1/24). However, due to the increased prevalence of Borrelia spp. in Ixodes ricinus ticks in Poland and the recent emergence of new tick-borne infections, it is necessary to carefully evaluate the true risk of human infection with several pathogens using more sensitive and reliable diagnostic tools. This is the first report of human infection with Babesia spp. in Poland that has been confirmed by molecular techniques with homology of 98.9% to B. divergens or Babesia EU1.

The ecology of Bartonella spp. infections in two rodent communities in the Mazury Lake District region of Poland.

Prevalence and abundance of Bartonella spp. infections were studied over a 3-year period in woodland and grassland rodents in North-Eastern Poland. Prevalence of bacterial infections was similar in the two rodent communities, with one leading host species in each habitat (46.3% in Apodemus flavicollis versus 29.1% in Myodes glareolus in forest, or 36.9% in Microtus arvalis versus 13.7% in Mi. oeconomus in grassland). Prevalence/abundance of infections varied markedly across the 3 years with 2006 being the year of highest prevalence and abundance. Infections were more common during autumn months in My. glareolus and A. flavicollis, and in juvenile and young adult (age classes 1 and 2) My. glareolus and Mi. oeconomus than in adults (age class 3). Higher prevalence and abundance of Bartonella infections were found in male A. flavicollis in comparison to females. These data are discussed in relation to the parasite genotypes identified in this region and with respect to the role of various ecological factors influencing Bartonella spp. infections in naturally infected host populations.

Effects of an MHC-DRB genotype and allele number on the load of gut parasites in the bank vole Myodes glareolus.

The major histocompatibility complex (MHC) genes code for the proteins responsible for pathogen recognition. The MHC class II DRB gene is multiplicated in the bank vole, Myodes glareolus, with different numbers of loci found in different individuals. Possessing large numbers of loci should increase the probability of pathogen recognition, but according to the optimality hypothesis, there is a cost of possessing too many MHC alleles. Using 454 technology, we determined the individual DRB allelic diversity and related it to the load of intestinal parasites in voles collected from three sites separated by a distance of 12 to 27 km. The analysis of six microsatellite loci revealed significant population structure (F(ST) = 0.07). The sites differed significantly in the prevalence and abundance of nematode species as well. We found two significant associations between MHC alleles and the intensity of the infection with the most prevalent nematode, Aspiculuris tetraptera. One of these associations was population-specific. This result suggests that the directions of selection can differ between populations connected by a low level of gene flow, which may contribute to the maintenance of high DRB allele diversity. In accordance with the optimality hypothesis, individuals with an intermediate number of alleles carried the lowest number of nematode species and had the lowest prevalence of A. tetraptera. However, the intensity of infection with A. tetraptera was linearly and negatively associated with the number of alleles.

Utilisation of rodent species by larvae and nymphs of hard ticks (Ixodidae) in two habitats in NE Poland.

The impact of host identity and habitat type on the density of hard ticks (Ixodes ricinus and Dermacentor reticulatus) infections on rodents in forest and abandoned field habitats in NE Poland was investigated. Ixodes ricinus was most abundant in the forest system, but D. reticulatus, although rarer, was most abundant in the field system. Environmental humidity and the much lower density of rodents probably limited the abundance of I. ricinus larvae in the field system, although this tick was still common on Microtus oeconomus from around small ponds. Nymphs of I. ricinus were comparatively rare in the forest, probably because of infection of non-rodent hosts. Dermacentor reticulatus nymphs on the other hand were very much more common in the ears of Microtus species than would have been predicted based on larval densities. The impact of habitat change (in this case successional change following field abandonment) on tick densities is emphasised, and the role of Apodemus as an epidemiological bridge, linking woodland and field habitats, is highlighted.

Babesia canis and other tick-borne infections in dogs in Central Poland.

Vector-borne infections constitute increasing health problem in dogs worldwide, including sled dogs, dramatically decreasing the fitness of working dogs and even leading to death. In the period 2006-2008 eighty-two blood samples were collected from eight sled dog kennels in Central Poland. The prevalence of four vector-borne infections (Babesia canis, Bartonella sp., Anaplasma/Ehrlichia and Borrelia burgdorferi) was estimated in 82 sled dogs using PCR and nested PCR for diagnosis and the same methods were used to identify the vector-borne pathogens in 26 dogs presenting at veterinary clinics with symptoms of vector-borne diseases. None of four studied vector-borne pathogens was detected in samples originating from veterinary clinics. Among the remaining 82 dogs B. canis infections were confirmed in three dogs undergoing treatment for babesiosis. The DNA of tick-borne pathogens was also found among 22 (27.8%) of the 79 apparently healthy dogs, including 20 cases of B. canis infection (25.3%), one case of B. burgdorferi s.l. infection and one case of Anaplasma phagocytophilum infection. No evidence of Bartonella spp. and Ehrlichia canis infections were found in this set of samples. Sequencing of a Babesia fragment of 18S rDNA amplified from acute (n=5) and asymptomatic (n=5) cases revealed that all isolates were identical to the Babesia canis canis sequence, originally isolated from Dermacentor reticulatus ticks in Poland. A range of factors was shown to affect the distribution of babesiosis in sled dogs. The data are also discussed in respect to the health risk factors generated by asymptomatic B. canis infections and the efficiency of chemoprophylaxis measures taken by sled dog owners.