House dust mites (Acari: Pyroglyphidae) in the cities of Gdansk and Gdynia (northern Poland).

277 samples of house dust collected in 1996-1998 from 17 flats, three hospitals, two hotels and one students' hostel situated in the cities of Gdansk and Gdynia were subjected to acarological examination. Acari were found in 50 (37.3%) of 134 samples from the flats, in 11 (15.5%) of 71 samples from the hospitals and in 13 (18.1%) of 72 samples from the hotels. The majority of mites (91.6%) was found in samples that originated from the private flats. 95.0% of mites from the flats, 35.0% mites from the hotels and 8.0% mites from the hospitals belonged to two dust mite species of the family Pyroglyphidae: Dermatophagoides pteronyssinus and Dermatophagoides farinae. D. farinae was significantly predominant and composed 82.8% of the whole pyroglyphid collection. Samples from private flats contained significantly more mites than those from hospitals and hotels: mean mites densities per 1 gram of dust were 13.07, 1.03 and 1.00, respectively. The authors suggest that only density of house dust mites in private flats may be clinically important.

Detection of three genospecies of Borrelia burgdorferi sensu lato in Ixodes ricinus ticks collected in different regions of Poland.

Ixodes ricinus ticks, collected in 1996-1998 in different Polish woodlands, were examined to assess the frequency of the occurrence of Lyme borreliosis-associated genospecies. A total of 568 samples of individual adults and 162 samples of individual (n =48) and pooled (of 2 to 7) samples of nymphs were analysed by the polymerase chain reaction (PCR) for Borrelia burgdorferi sensu lato. Spirochetes were detected in 130 adult ticks (22.9%) and in a minimum of 32 (5.3%) nymphs. Further identification of 153 B. burgdorferi s.l.-positive samples by nested PCR using three species-specific primers revealed the occurrence of B. afzelii, B. burgdorferi sensu stricto and B. garinii. Both single-species and mixed infections were noted. Single-species infections were observed in the majority of samples (n = 83/153; 54.2%). Within this group B. afzelii was found in 38/153 samples (24.9%), followed by B. burgdorferi sensu stricto (n = 23/153; 15.0%) and B. garinii (n = 22/153; 14.4%). Dual infections with B. burgdorferi s.s. and B. afzelii were detected in 17/121 (14.0%) adults, while both B. burgdorferi s. s./B. garinii and B. afzelii/B. garinii coinfected 11/121 (9.1%) adult ticks. Triple infection with B. burgdorferi s.s., B. afzelii and B. garinii was noted twice (1.6%). In general, B. afzelii was found in 72/153 (47.1%) tick samples and was the predominant species. B. burgdorferi s. s. and B. garinii were detected in a total of 60/153 (39.2%) and 51/153 (33.3%) samples, respectively. Although, 21 (13.7%) samples were infected by B. burgdorferi s.l. genospecies undetectable by the primers used, results of our study confirm that Lyme borreliosis pathogenic genospecies are well established in tick populations throughout Poland.

Prevalence of Borrelia burgdorferi sensu lato in Ixodes ricinus ticks (Acari, Ixodidae) in different Polish woodlands.

In 1996-1998, a total of 2285 Ixodes ricinus ticks (1063 nymphs, 637 males, 585 females) were collected from vegetation from 25 different localities in the 8 Polish provinces throughout the country. Ticks inhabited all 25 collection sites. The average number of ticks per collection site was 91.4 +/- 13.7. All 2285 ticks were examined for Borrelia burgdorferi sensu lato (s.l.) presence, of which 1333 specimens from 3 provinces were tested by routine indirect immunofluorescence assay (IFA) using polyclonal antibody PAB 1B29. The remaining 952 specimens from 5 provinces were examined by polymerase chain reaction (PCR), using FL6 and FL7 primers. The overall infection rate in ticks estimated by these 2 methods was 10. 2%. Nymphs showed lower positivity rate (6.2%) as compared to adult ticks (14.9% in females and 12.4% in males). The highest percentage of infected I. ricinus ticks (37.5%) was noted in the Katowice province while the lowest (4.1%) in the Bia ystok province. In particular collection sites, infection rates varied from 0-37.5%. The obtained results confirmed that B. burgdorferi s.l. is present throughout the distributional areas of I. ricinus in Poland and that a prevalence of spirochete-infected ticks may be high in some locations.

The etiological agent of Lyme disease, Borrelia burgdorferi, in ticks (Acari:Ixodidae) from eastern Poland.

In 1994, 4204 out of 4656 Ixodes ricinus collected both from vegetation in three different areas and from hunter-killed deer and wild boar in the Bialystok province (eastern Poland) were examined individually for the presence of Borrelia burgdorferi s.I. Detection of spirochetes was carried out by the routine indirect immunofluorescence assay (IFA) using polyclonal antibody (anti-B. burgdorferi, strain 1 B 29). B. burgdorferi spirochetes were evident in 349 (8.8%) nymphal and adult I. ricinus collected from vegetation (n = 3958) and in 8 (3.2%) of those removed from hosts (n = 246). Among the ticks collected from vegetation, infection rates in nymphs (5.8-6.4%) in particular areas were about 2-4 times lower than in adults (8.1-24.6%). The calculated minimal and maximal infection rates of ticks collected from different sites were 1.6% and 15.4%, respectively. Prevalence of B. burgdorferi in I. ricinus was determined with respect to the abundance and seasonal activity of the ticks.

[The prevalence of Ixodes ricinus ticks (Acari, Ixodidae) in the forested areas of Gdansk, Sopot, and Gdynia and their infection rate with Borrelia burgdorferi spirochetes]. / Wystepowanie kleszczy Ixodes ricinus (Acari, Ixodidae) na zalesionych obszarach Trojmiasta i ich zakazenie kretkami Borrelia burgdorferi.

Data are presented on the variable patterns on the seasonal activity of Ixodes ricinus questing on vegetation in 6 study sites in the forested areas of Gdansk, Sopot and Gdynia in 1993-1995. A total of 8992 specimens collected there show that ticks frequently occupy habitats closely associated with man. Out of them 5775 (4328 nymphs, 713 females and 680 males) collected in 1994 and 1995 were examined individually for Borrelia burgdorferi sensu lato-the etiologic agent of Lyme borreliosis-using in-direct immunofluorescence assay (IFA). Spirochetes were detected in 577 (10.3%) of the ticks tested. The overall infection rate was 8.2% for nymphs (n = 353), 14.9% for females (n = 102) and 18.9% for males (n = 122). The infection rates in particular study sites varied between 1.4% and 16.4% in 1994 and between 3.6% and 26.9% in 1995. The highest prevalence of B. burgdorferi was observed in June (10%) and October (11.9%) in 1994 and in August (16.3%) and October (25%) in 1995. Detection of B. burgdorferi in ticks derived from the same area in the two following years shows that the infection of the I. ricinus population with this pathogen in the forested areas of Gdansk, Sopot and Gdynia is permanent.

Occurrence of pediculosis capitis in a population of children from Gdansk, Sopot, Gdynia and the vicinities.

Elementary schools in Gdansk, Sopot, Gdynia and the neighbourhood, were studied during 1990-1992 to determine the actual extent of head louse infestation in school children as well as to see if there was correlation between incidence of head lice (Pediculus humanus capitis) and some environmental factors as: the sex and the age of a child, the parents education, family situation and living condition of a child etc.--In the examined sample of normal population of 27,800 school children (aged 6-15 years) 881 (3.2%) pupils were infested with head lice, with the incidence being higher in girls. As many as 382 cases (1.3%) were qualified as a focal type, i.e. with stubborn, repeated reinfestations after following treatments. In the group with focal pediculosis 48.9% and 79.4% of children originated from the families of 4 or more children and from the families where parents had only elementary or trade education. Later, over 50% (53.3-56.6%) of village elementary school children focally infested with head lice lived in old houses mostly supplied only with cold water or even without running water at all. These data confirm the association between head louse infestation and familial, social and hygienic conditions of an infested child.

Occurrence of Borrelia spirochaetes in ticks (Acari, Ixodidae) collected in the forest areas in Olsztyn province (north central Poland).

In 1993, 2178 out of 3816 Ixodes ricinus and 45 out of 82 Dermacentor reticulatus collected from vegetation at 35 sites and removed from hunter-killed deer in Olsztyn province (N. C. Poland) were examined individually for the presence of Borrelia spirochaetes. Detection of spirochaetes was carried out by the routine indirect immunofluorescence assay (IFA) using polyclonal antibody anti-B. burgdorferi, strain 1 B 29. Borreliae, presumably B. burgdorferi, were evident in 192 (11.5%) I. ricinus (nymphs and adults) collected from vegetation (n = 1666) and in 6 (1.2%) of those removed from hosts (n = 512). Among the first ones, infection rate in nymphs (7.5%) was 2.5 times lower than in adults (18.8%) but was similar in females (18.7%) and males (18.9%). The calculated minimal and maximal infection rates of ticks collected from different locations were 2.9% and 35.7%, respectively. No spirochetes were observed in D. reticulatus tested.

Evaluation of the effectiveness of carbamates and pyrethroids against cockroaches--Blattella germanica (L.) on ships and in a port town.

The laboratory tests were aimed at determination of the effectiveness of 3 insecticides: propoxur, permethrin and deltamethrin against cockroaches, Blattella germanica (L.) caught on Polish merchant ships and in some communal buildings in the town Gdynia. The contact method with use of glass jars was applied. A total of 1700 specimens of B. germanica (males, females and larvae) has been examined. In this material there were: 720 specimens from ships, 620 from communal buildings and 360 from susceptible laboratory colony. There were carried out 116 tests: 37 with propoxur, 38 with permethrin and 41 with deltamethrin. The controls involved: 27 tests with acetone and 27 with use of the B. germanica (L.) susceptible strain. Out of the insecticides tested a very high effectiveness was shown in case of deltamethrin--in regard to all the cockroaches under investigation, and propoxur--against the cockroaches from the communal buildings. The toxic efficacy of permethrin was low.

Laboratory investigations on the effect of selected disinfectants on survival of the cockroaches Blattella germanica (L.).

It was ascertained that lysol 2% and 5% showed the most toxic effect in control of cockroaches in the contact method (23.3% and 95.5% mortality after 24 hours of exposure), and that chloramine 1%, 3% and 5% was the most effective food poison (after 19 days exposure 100% of the insects died). When injecting disinfectant into the body cavity, the cockroaches showed a ten times higher sensibility to formalin and chloramine than to lysol. The use, however, of disinfectant in the contact method (particularly lysol 2%) together with an insecticide based on propoxur, allowed to reduce its dose to a half, what gave better results than the use of an insecticide alone in a normal dose.