Cats as a sentinel species for human infectious diseases - toxoplasmosis, trichinellosis, and COVID-19.

In this study, serological screening for Toxoplasma gondii, Trichinella spp., and SARS-CoV-2 in domestic cats was conducted, aiming to identify their exposure to the mentioned pathogens and to assess the risk of potential human infection. In total, serum samples from 481 (310 owned and 171 shelter cats) were collected in Bratislava from September 2020 to September 2021, a period that included the initial outbreak wave of the COVID-19 pandemic. The study showed a 37.4% (135/441) seroprevalence of T. gondii with a slightly lower seropositivity in shelter cats (35.9%; 61/170) than in owned cats (38.4%; 104/271), but this difference was not statistically significant. Overall, the seroprevalence of Trichinella spp. was 2.0% (9/441), with animals from shelters being positive but not significantly more often (2.9%; 5/170) than owned cats (1.5%; 4/271). SARS-CoV-2 antibodies were detected in 2.7% (13/481) of cat sera (2.9% in shelter cats; 2.6% in owned cats). Among ten samples positive by virus neutralisation assay, two were positive for the B.1 variant. The presence of the SARS-CoV-2 virus in buccal and rectal swabs (n = 239) was not detected. The seroprevalence of almost 40% for T. gondii in cats suggests a non-negligible risk of human infection. The study confirmed the possibility of Trichinella spp. infection in cats, and thus the possibility of infection spreading between the sylvatic and synanthropic cycle via this animal species. The presented results also showed that the SARS-CoV-2 virus is likely to circulate in cat populations in Slovakia, not only in cats that may have been in contact with infected persons, but also in shelter cats.

The role of wildlife in the epidemiology of tick-borne diseases in Slovakia.

Tick-borne diseases (TBD) represent an important challenge for human and veterinary medicine. In Slovakia, studies on the epidemiology of tick-borne pathogens (TBP) regarding reservoir hosts have focused on small mammals and to a lesser extent on birds or lizards, while knowledge of the role of the remaining vertebrate groups is limited. Generally, wild ungulates, hedgehogs, small- and medium-sized carnivores, or squirrels are important feeding hosts for ticks and serve as reservoirs for TBP. Importantly, because they carry infected ticks and/or are serologically positive, they can be used as sentinels to monitor the presence of ticks and TBP in the environment. With their increasing occurrence in urban and suburban habitats, wild ungulates, hedgehogs or foxes are becoming an important component in the developmental cycle of Ixodes ricinus and of TBP such as Anaplasma phagocytophilum or Babesia spp. On the other hand, it has been postulated that cervids may act as dilution hosts for Borrelia burgdorferi (sensu lato) and tick-borne encephalitis virus. In southwestern Slovakia, a high prevalence of infection with Theileria spp. (100%) was observed in some cervid populations, while A. phagocytophilum (prevalence of c.50%) was detected in cervids and wild boars. The following pathogens were detected in ticks feeding on free-ranging ungulates, birds, and hedgehogs: A. phagocytophilum, Rickettsia spp., Coxiella burnetii, Neoehrlichia mikurensis, B. burgdorferi (s.l.), and Babesia spp. The growing understanding of the role of wildlife as pathogen reservoirs and carriers of pathogen-infected ticks offers valuable insights into the epidemiology of TBP, providing a foundation for reducing the risk of TBD.

Pathogenic microorganisms in ticks removed from Slovakian residents over the years 2008-2018.

A total of 750 ticks feeding on humans were collected during the years 2008-2018. The majority of ticks (94.8 %) came from Slovakia, with 3.5 % from the Czech Republic, 0.9 % from Austria, and 0.3 % from Hungary. Travellers from Ukraine, Croatia, France, and Cuba also brought one tick from each of these countries. The majority of the analysed ticks were identified as Ixodes ricinus (94.3 %). Dermacentor reticulatus (0.93 %), Haemaphysalis concinna (0.1 %), Haemaphysalis sp. (0.1 %), Ixodes arboricola (0.1 %), and Rhipicephalus sp. (0.1 %) were also encountered. The most frequently found stage of I. ricinus was the nymph (69.9 %) followed by adult females (20.4 %) and larvae (8.3 %). Ticks were predominantly found on children younger than 10 years (46.3 %) and adults between 30-39 years (21.4 %). In children younger than 10 years, the ticks were usually found on the head, while in other age categories, the ticks were predominantly attached to legs. Ticks were further individually analysed for the presence of Rickettsia spp., Coxiella burnetii, Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Neoehrlichia mikurensis, Bartonella spp. and Babesia spp. The overall prevalences of tick-borne bacteria assessed in I. ricinus ticks acquired in Slovakia were: rickettsiae 25.0 % (95 % CI: 21.7-28.2), B. burgdorferi s.l. 20.5 % (95 % CI: 17.4-23.5), A. phagocytophilum 13.5 % (95 % CI: 10.9-16.0), Babesia spp. 5.2 % (95 % CI: 3.5-6.9), C. burnetii 3.0 % (95 % CI: 1.5-4.6), and N. mikurensis 4.4 % (95 % CI: 2.0-6.8). Pathogenic species Rickettsia raoultii, Rickettsia helvetica, Rickettsia monacensis, A. phagocytophilum, Borrelia garinii, Borrelia afzelii, Borrelia valaisiana, Babesia microti, and Babesia divergens were identified in D. reticulatus and I. ricinus ticks.

Local Population Structure and Seasonal Variability of Borrelia garinii Genotypes in Ixodes ricinus Ticks, Slovakia.

Lyme disease (LD) is the most common tick-borne human disease in Europe, and Borrelia garinii, which is associated with avian reservoirs, is one of the most genetically diverse and widespread human pathogenic genospecies from the B. burgdorferi sensu lato (s.l.) complex. The clinical manifestations of LD are known to vary between regions and depend on the genetic strain even within Borrelia genospecies. It is thus of importance to explore the genetic diversity of such pathogenic borreliae for the wide range of host and ecological contexts. In this study, multilocus sequence typing (MLST) was employed to investigate the local population structure of B. garinii in Ixodes ricinus ticks. The study took place in a natural wetland in Slovakia, temporally encompassing spring and autumn bird migration periods as well as the breeding period of resident birds. In total, we examined 369 and 255 ticks collected from 78 birds and local vegetation, respectively. B. burgdorferi s.l. was detected in 43.4% (160/369) of ticks recovered from birds and in 26.3% (67/255) of questing ticks, respectively. Considering the ticks from bird hosts, the highest prevalence was found for single infections with B. garinii (22.5%). Infection intensity of B. garinii in bird-feeding ticks was significantly higher than that in questing ticks. We identified ten B. garinii sequence types (STs) occurring exclusively in bird-feeding ticks, two STs occurring exclusively in questing ticks, and one ST (ST 244) occurring in both ticks from birds and questing ticks. Four B. garinii STs were detected for the first time herein. With the exception of ST 93, we detected different STs in spring and summer for bird-feeding ticks. Our results are consistent with previous studies of the low geographic structuring of B. garinii genotypes. However, our study reveals some consistency in local ST occurrence and a geographic signal for one of the clonal complexes.

Tick-borne pathogens and their reservoir hosts in northern Italy.

The aim of this study was to determine the occurrence of Anaplasma phagocytophilum, Rickettsia spp., Babesia spp., and Candidatus Neoehrlichia mikurensis in Ixodes spp. ticks removed from wildlife, domestic animals and humans in the Province of Trento (northern Italy) in order to better understand their ecology and provide public health professionals with an updated list of pathogens which should be considered during their diagnostic procedures after a tick bite. During 2011-2012, 848 feeding ticks at all life stages (adults, nymphs and larvae) from various hosts (wild ungulates, birds and rodents; domestic sheep, dogs and humans) were collected. The highest prevalences of A. phagocytophilum and Rickettsia spp. were detected in adult and nymphal tick stages feeding on wild ungulates (11.4% prevalence for both pathogens), while the Babesia spp. prevailed in nymphal and larval ticks feeding on wild birds (7.7%). A wide spectrum of tick-borne agents was present in larval ticks: those detached from wild ungulates were positive for A. phagocytophilum, B. venatorum, R. helvetica, R. monacensis and R. raoultii, while those removed from wild rodents were positive for B. venatorum, R. helvetica, R. monacensis and Ca. N. mikurensis, and ticks from wild birds carried A. phagocytophilum, B. venatorum, B. capreoli and R. helvetica. This study provides evidence of circulation of five tick-borne pathogens not reported in this region before, specifically R. raoultii, R. monacensis, B. venatorum, B. capreoli and B. microti. Furthermore, it discusses the epidemiological role of the animal species from which the ticks were collected highlighting the needs for more experimental studies especially for those pathogens where transovarial transmission in ticks has been demonstrated.

Borrelia afzelii gene expression in Ixodes ricinus (Acari: Ixodidae) ticks.

Spirochetes belonging to the Borrelia burgdorferi sensu lato (s. l.) complex have evolved remarkable ability to survive in diverse ecological niches during transmission cycles between ticks and vertebrate hosts by variable gene expression. To understand the events during spirochete transmission from feeding ticks to hosts, mRNA levels of selected B. afzelii genes (bbk32, dbpA, ospA, ospC and vlsE) were measured by quantitative real-time SYBR Green PCR. B. afzelii infected Ixodes ricinus nymphs fed on laboratory BALB/c mice for 0, 24, 48, and 72 hours. The mRNA levels of the constantly expressed flagellin gene were used for the relative quantification of selected genes. Differences in gene expression profiles were observed in unfed ticks and during tick feeding. mRNA levels of bbk32 and dbpA showed distinctive decreasing patterns during the first 24 hours post-attachment, while ospC and vlsE mRNA levels increased significantly during the feeding process. In contrast, ospA levels decreased for the 48 hours of tick feeding and slightly increased by 72 hours. More detailed and comprehensive studies on regulation of gene expression in different Borellia genospecies on the vector-host interface would aid to develop effective strategies in preventing pathogen transmission.

Natural foci of Borrelia lusitaniae in a mountain region of Central Europe.

Lyme borreliosis is the most prevalent tick-borne disease in Europe. It is caused by spirochaetes of the Borrelia burgdorferi sensu lato (s.l.) complex and transmitted to humans by ticks of the genus Ixodes. Borrelia afzelii, Borrelia garinii, and Borrelia valaisiana are the most common genospecies in Central Europe. In contrast, Borrelia lusitaniae predominates in Mediterranean countries such as Portugal, Morocco, and Tunisia. In Slovakia, its prevalence is low and restricted to only a few sites. The aim of our research was to study the expansion of ticks into higher altitudes in the ecosystem of the Malá Fatra mountains (north Slovakia) and their infection with B. burgdorferi s.l. pathogens. Questing ticks were collected by flagging in seven years (2004, 2006-2011) at three different altitudes: low (630-660 m above sea level (ASL)), intermediate (720-750 m ASL), and high (1040-1070 m ASL). Tick abundance was highest at the lowest altitude and lowest at the highest altitude. The average infection prevalence of B. burgdorferi s.l. in nymphs and adults was 16.8% and 36.2%, respectively. The number of infected ticks decreased from 38.5% at the lowest altitude to 4.4% at the highest altitude. B. lusitaniae was the most frequently found genospecies (>60% of the ticks found positive for B. burgdorferi s.l.) in all sites in all the studied years with the exception of 2008 when B. afzelii predominated (62%). Our study confirms the spread of Ixodes ricinus ticks to higher altitudes in Slovakia. The discovery that our mountain study sites were a natural foci of B. lusitaniae was unexpected because this genospecies is usually associated with lizards and xerothermic habitats.

Rickettsial infection in Ixodes ricinus ticks in urban and natural habitats of Slovakia.

A total of 1810 Ixodes ricinus ticks was collected from the vegetation from 2 different habitat types: urban and natural. Urban habitats were represented by cemeteries and public parks in the following towns: Bratislava, Malacky, and Martin at 150 m and 400 m above sea level. Natural habitats were selected in the mountain forest of the Martinské hole Mts. in Central Slovakia at 3 different altitudinal levels, i.e. 600 m, 800 m and 1000 ma.s.l. All ticks were tested for the presence of spotted fever group rickettsiae. The DNA of Rickettsia spp. was identified in 9% of all tested ticks. Rickettsia-infected ticks were present in both, urban and sylvatic sites at all studied altitudes. Four different species of Rickettsia were present in positive I. ricinus ticks. Rickettsia helvetica was identified in 77 out of 87 Rickettsia-positive I. ricinus ticks, followed by 8 samples that belonged to Rickettsia monacensis and 2 of the positive ticks were infected with different unidentified Rickettsia spp. Due to the association of R. helvetica and R. monacensis with human infections, it is essential to understand which species of Rickettsia circulate in the natural foci of Slovakia. Circulation of pathogenic rickettsiae in urban as well as natural habitats at different altitudinal levels in Slovakia emphasizes that infection risk is very common throughout this Central European country.

Candidatus Neoehrlichia mikurensis and its co-circulation with Anaplasma phagocytophilum in Ixodes ricinus ticks across ecologically different habitats of Central Europe.

BACKGROUND: Candidatus Neoehrlichia mikurensis is a newly emerging tick-borne bacterium from the family Anaplasmataceae. Its presence in Ixodes ricinus ticks was reported from various European countries, however, it's ecology and co-circulation with another member of the same family, Anaplasma phagocytophilum has not been rigorously studied yet. FINDINGS: Candidatus N. mikurensis was detected in all sampling sites. In total, 4.5% of ticks were positive including larvae. The highest positivity was detected in Austria with a prevalence of 23.5%. The probability of Candidatus N. mikurensis occurrence increased with the proportion of ticks infected with Anaplasma phagocytophilum. CONCLUSION: A positive association between the occurrences of Candidatus N. mikurensis and A. phagocytophilum indicates that both bacteria share similar ecology for their natural foci in Central Europe.

The invasion history, distribution and colour pattern forms of the harlequin ladybird beetle Harmonia axyridis (Pall.) (Coleoptera, Coccinellidae) in Slovakia, Central Europe.

The harlequin ladybird beetle Harmonia axyridis (Coleoptera, Coccinellidae) has invaded and established in Slovakia. Following unintentional introduction in 2008, the spread of the alien coccinellid was very fast. By the end of 2009, it was recorded across the whole country, and by the end of 2012 it was widely distributed and common in various habitats, particularly gardens, orchards and urban areas, where it was most frequent on trees. The rate of eastward spread was approximately 200 km year(-1), similar to the overall rate of spread in Europe. Between 2008 and 2012, the coccinellid was recorded in a total of 153 localities, in altitudes ranging from 98 to 1,250 m. Most records of this species were made in lowlands, hilly areas and valleys separating mountain ridges. However, it was only rarely documented in areas above 700 m a.s.l. The non-melanic colour form (f. succinea) was dominant along a longitudinal transect including eight urban areas across Slovakia, with the frequency of melanic forms (f. spectabilis and f. conspicua together) between 6.3 and 19.2% and a median equal to 10.5%. The invasion history and distribution of H. axyridis in Slovakia are discussed with regard to the time sequence of records, rate of spread, altitudinal distribution, anthropogenic dispersal, effective recording, proportion of melanic forms and other relevant aspects associated with the spread of this successful invader.