Streptococcus suis (ex Elliot 1966, Kilpper-Bälz & Schleifer 1987) is a facultatively anaerobic Gram-positive ovoid or coccal bacterium surrounded by a polysaccharide capsule. Based on the antigenic diversity of the capsule, S. suis strains are classified serologically into 35 serotypes. Streptococcus suis is a commensal of pigs, commonly colonizing their tonsils and nasal cavities, mostly in weaning piglets between 4-10 weeks of age. This species occurs also in cattle and other mammals, in birds and in humans. Some strains, mostly those belonging to serotype 2, are also pathogenic for pigs, as well as for other animals and humans. Meningitis is the primary disease syndrome caused by S. suis, both in pigs and in humans. It is estimated that meningitis accounted for 68.0% of all cases of human disease reported until the end of 2012, followed by septicaemia (including life-threatening condition described as 'streptococcal toxic shock-like syndrome' - STSLS), arthritis, endocarditis, and endophthalmitis. Hearing loss and/or ves tibular dysfunction are the most common sequelae after recovery from meningitis caused by S. suis, occurring in more than 50% of patients. In the last two decades, the number of reported human cases due to S. suis has dramatically increased, mostly due to epidemics recorded in China in 1998 and 2005, and the fulminant increase in morbidity in the countries of south-eastern Asia, mostly Vietnam and Thailand. Out of 1,642 cases of S. suis infections identified between 2002-2013 worldwide in humans, 90.2% occurred in Asia, 8.5% in Europe and 1.3% in other parts of the globe. The human disease has mostly a zoonotic and occupational origin and occurs in pig breeders, abattoir workers, butchers and workers of meat processing facilities, veterinarians and meat inspectors. Bacteria are transmitted to workers by close contact with pigs or pig products, usually through contamination of minor cuts or abrasions on skin of hands and/or arms, or by pig bite. A different epidemiologic situation occurs in the Southeast Asian countries where most people become infected by habitual consumption of raw or undercooked pork, blood and offal products in the form of traditional dishes. Prevention of S. suis infections in pigs includes vaccination, improvement in pig-raising conditions, disinfection and/or fumigation of animal houses, and isolation of sick animals at the outbreak of disease. Prevention of human infections comprises: protection of skin from pig bite or injury with sharp tools by people occupationally exposed to pigs and pig products, prompt disinfection and dressing of wounds and abrasions at work, protection of the respiratory tract by wearing appropriate masks or repirators, consulting a doctor in the case of febrile illness after exposure to pigs or pork meat, avoidance of occupations associated with exposure to pigs and pork by immunocompomised people, avoidance of consumption of raw pork or pig blood, adequate cooking of pork, and health edu...

Occurrence of co-infections with various pathogens in ixodid ticks creates a risk of increased severity of tick-borne diseases in humans and animals exposed to bite of the ticks carrying multiple pathogens. Accordingly, co-infections in ticks were subject of numerous analyses, but almost exclusively with regard to Ixodes ricinus complex whereas potential tick vectors belonging to other genera were much less studied. Taking into consideration the role of Dermacentor reticulatus in the transmission of various pathogens, we carried out for the first time the comprehensive statistical analysis of co-infections occurring in this tick species. An attempt was made to determine the significance of the associations between 6 different pathogens occurring in D. reticulatus (Tick-borne encephalitis virus = TBEV, Anaplasma phagocytophilum, Rickettsia raoultii, Borrelia burgdorferi s. l., Babesia spp., Toxoplasma gondii), using 2 statistical methods: determination of Odds Ratios (ORs) and the Fisher's exact test. 634 questing Dermacentor reticulatus ticks (370 females and 264 males) were collected in 2011-2013 by flagging the lower vegetation in 3 localities in the area of Łęczyńsko-Włodawskie Lakeland, situated in the Lublin region of eastern Poland. The presence of individual pathogens was detected by PCR. Ticks were infected most often with Rickettsia raoultii (43.8%), less with TBEV (8.5%), and much less with Babesia spp., Toxoplasma gondii, Borrelia burgdorferi s.l., and Anaplasma phagocytophilum (2.5%, 2.1%, 1.6% and 1.1%, respectively). The locality-dependent variability proved to be significant for TBEV (c 2 =11.063; P=0.004) and Toxoplasma gondii (c 2 =11.298; P=0.0035), but not for other pathogens. Two hundred seventy (42.6%) of the examined ticks were infected only with a single pathogen, and 54 (8.5%) showed the presence of dual co-infections, each with 2 pathogens. The most common were dual infections with participation of Rickettsia raoultii (7.41%); next, those with participation of the TBEV (5.21%), Toxoplasma gondii (1.58%), Borrelia burgdorferi s.l. (1.26%), Anaplasma phagocytophilum (0.95%), and Babesia spp. (0.63%). On the total number of 15 possible associations, in 9 cases co-infections occurred whereas in 6 cases they were not detected. The most noteworthy were positive co-infections with the participation of TBEV, which proved to be weakly significant (0.05

Streptococcus suis is a re-emerging zoonotic pathogen that may cause severe disease, mostly meningitis, in pigs and in humans having occupational contact with pigs and pork, such as farmers, slaughterhose workers and butchers. The first stage of the pathogenic process, similar in pigs and humans, is adherence to and colonisation of mucosal and/or epithelial surface(s) of the host. The second stage is invasion into deeper tissue and extracellular translocation of bacterium in the bloodstream, either free in circulation or attached to the surface of monocytes. If S. suis present in blood fails to cause fatal septicaemia, it is able to progress into the third stage comprising penetration into host's organs, mostly by crossing the blood-brain barrier and/or blood-cerebrospinal fluid barrier to gain access to the central nervous system (CNS) and cause meningitis. The fourth stage is inflammation that plays a key role in the pathogen esis of both systemic and CNS infections caused by S. suis. The pathogen may induce the overproduction of pro-inflammatory cytokines that cause septic shock and/or the recruitment and activation of different leukocyte populations, causing acute inflammation of the CNS. Streptococcus suis can also evoke - through activation of microglial cells, astrocytes and possibly other cell types - a fulminant inflammatory reaction of the brain which leads to intracranial complications, including brain oedema, increased intracranial pressure, cerebrovascular insults, and deafness, as a result of cochlear sepsis. In all stages of the pathogenic process, S. suis interacts with many types of immunocompetent host's cells, such as polymorphonuclear leukocytes, mononuclear macrophages, lymphocytes, dendritic cells and microglia, using a range of versatile virulence factors for evasion of the innate and adaptive immune defence of the host, and for overcoming environmental stress. It is estimated that S. suis produces more than 100 different virulence factors that could be classified into 4 groups: surface components or secreted elements, enzymes, transcription factors or regulatory systems and transporter factors or secretion systems. A major virulence factor is capsular polysaccharide (CPS) that protects bacteria from phagocytosis. However, it hampers adhesion to and invasion of host's cells, release of inflammatory cytokines and formation of the resistant biofilm which, in many cases, is vital for the persistence of bacteria. It has been demonstrated that the arising by mutation unencapsulated S. suis clones, which are more successful in penetration to and propagation within the host's cells, may coexist in the organism of a single host together with those that are encapsulated. Both 'complementary' clones assist each other in the successful colonization of host's tissues and persistence therein. S. suis has an open pan-genome characterized by a frequent gene transfer and a large diversity. Of the genetic determinants of S. suis pathogenicity, t...

A total of 853 questing Ixodes ricinus males, females, and nymphs and of 582 questing Dermacentor reticulatus males and females were collected from vegetation on the territory of the Lublin province (eastern Poland). The ticks were examined for the presence of Babesia by PCR detecting part of 18S ribosomal RNA (rRNA) gene and nuclear small subunit rRNA (SS-rDNA) for determining of Babesia spp. and Babesia microti, respectively. The overall incidence of Babesia strains in I. ricinus ticks was 4.6 %. Three species of Babesia were identified. The prevalent species was B. microti which occurred in 2.8 % of ticks, while Babesia venatorum, Babesia divergens, and unidentified Babesia species were found at the frequency of 1.2, 0.2, and 0.3 %, respectively. Altogether, B. microti constituted 61.5 % of the total strains detected in I. ricinus, B. venatorum—25.7 %, B. divergens—5.1 %, and unidentified Babesia species—7.7 %. The prevalence of Babesia species in I. ricinus did not depend significantly on locality (χ2 = 1.885, P = 0.390) nor on the tick stage (χ2 = 4.874, P = 0.087). The incidence of Babesia strains in D. reticulatus ticks was 2.7 %. Two species of Babesia were identified. Again, the prevalent species was B. microti which occurred in 2.1 % of ticks, while B. canis was found in 0.7 % of ticks. In one D. reticulatus female, B. canis and B. microti co-infection was found. Altogether, B. microti constituted 75 % of the total strains detected in D. reticulatus while B. canis formed 25 % of the total strains. The frequency of the occurrence of Babesia species in D. reticulatus did not depend significantly on locality (χ2 = 0.463, P = 0.793). The difference between the prevalence of Babesia in males and females of D. reticulatus was insignificant (P = 0.0954); nymphs were not found. The dominance of B. microti in the species composition of tick-borne Babesia found in this study was typical for eastern Europe. In conclusion, the results revealed that the population inhabiting the forested area of eastern Poland could be exposed to Babesia parasites, especially to those from the species B. microti, by a bite of I. ricinus, a competent vector of human babesiosis, and probably also by a bite of D. reticulatus whose role in the transmission of human babesiosis needs to be clarified.

No abstract

Spiroplasma is a genus of wall-less, low-GC, small Gram-positive bacteria of the internal contractile cytoskeleton, with helical morphology and motility. The genus is classified within the class Mollicutes. Spiroplasma / host interactions can be classified as commensal, pathogenic or mutualist. The majority of spiroplasmas are found to be commensals of insects, arachnids, crustaceans or plants, whereas a small number of species are pathogens of plants, insects, and crustaceans. Insects are particularly rich sources of spiroplasmas. The bacteria are common in haematophagous arthropods: deerflies, horseflies, mosquitoes, and in ticks, where they may occur abundantly in salivary glands. The ability of spiroplasmas to propagate in rodents was experimentally proven, and Spiroplasma infections have been reported recently in humans. Some authors have purported an etiological role of Spiroplasma in causing transmissible spongiform encephalopathies (TSEs), but convincing proof is lacking. The possibility for humans and other vertebrates to be infected with Spiroplasma spp. in natural conditions is largely unknown, as well as the possibility of the transmission of these bacteria by ticks and haematophagous insects. Nevertheless, in the light of new data, such possibilities cannot be excluded.

In the years 2008-2009 and 2013-2014, 1620 and 1500 questing Ixodes ricinus ticks, respectively, were examined on the territory of the Lublin province (eastern Poland). The presence of three pathogenic species causing Lyme disease was investigated: Borrelia burgdorferi sensu stricto, B. afzelii and B. garinii. The proportion of I. ricinus ticks infected with B. burgdorferi sensu lato showed a highly significant increase between 2008-2009 and 2013-2014, from 6.0 to 15.3 %. A significant increase was noted with regard to all types of infections with individual species: single (4.7-7.8 %), dual (1.2-6.6 %), and triple (0.1-0.9 %). When expressed as the percent of all infections, the frequency of mixed infections increased from 21.4 to 49.2 %. Statistical analysis performed with two methods (by calculating of odds ratios and by Fisher's exact test) showed that the frequencies of mixed infections in most cases proved to be significantly greater than expected. The strongest associations were found between B. burgdorferi s. s. and B. afzelii, and between B. burgdorferi s. s. and B. garinii. They appeared to be highly significant (P \ 0.0001) when assessed by two methods for 2013-2014, and for the sum of findings for both time periods. The proportions of the individual species detected in the mixed infections in 2008-2009 and 2013-2014 revealed highly significant increases for B. burgdorferi s. s. and B. garinii (from 33.9 to 71.1 % and from 18.2 to 82.9 %, respectively), and an insignificant decrease for B. afzelii (from 51.4 to 41.6 %). The proportions of the species B. burgdorferi s. s., B. afzelii and B. garinii (with combined single and mixed infections) for 2008-2009 and 2013-2014 were: 51.2/44.0 %, 30.6/24.9 % and 18.2/31.1 %, respectively. In conclusion, our results seem to indicate the detrimental trend of the increasing infection rate of I. ricinus ticks with B. burgdorferi s. l. in eastern Poland, and dramatic enhancement of mixed infections with individual species, which may result

Blood serum samples collected from randomly selected groups of 32 pigs and 41 cows reared in farms belonging to the rural community "A" located in eastern Poland and exposed to the Vistula river floods, and serum samples from groups of 41 pigs and 40 cows from farms belonging to the rural community "B" located also in eastern Poland but not in the area exposed to floods, were examined by the microscopic agglutination test for the presence of antibodies against 18 Leptospira serovars. The percentage of serum samples presenting positive results with at least one serovar were higher in pigs and cows from community "A" comparing to community "B" (34.4% vs. 4.9% and 26.8% vs. 15.0%, respectively). In the case of pigs, the difference was statistically significant (P=0.0015). The reactions with 12 Leptospira serovars (Australis, Bataviae, Bratislava, Canicola, Hardjo, Hebdomadis, Icterohaemorrhagiae, Pomona, Poi, Cynopteri, Grippotyphosa, Celledoni,), belonging to four species (L. interrogans, L. borgpetersenii, L. kirschneri, L. weili) were found in the examined animals. In community "B", six reactions with one serovar and two reactions with two serovars were noted whereas in community "A" -19 reactions with one serovar, one reaction with two serovars and two reactions with six serovars were observed. The titres in animals reared in community "A" were significantly higher (up to 25,600) compared to community "B" (up to 200, P=0.0094). The obtained results suggest that the exposure to flooding may increase the infection rate in pigs and cows from afflicted areas to some extent.