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The distribution of Dermatophagoides farinae and D. pteronyssinus in two groups of houses in Rome was investigated by means of weekly sampling of dust on mattresses during the period of high mite density (May-July, 1994). All mattresses were infested; overall 4,179 live and dead mites were collected. In the two examined areas, a difference in species distribution was observed. D farinae was always the prevalent species, it was 94.7% in area A and 64.1% in area B; only in houses 9 and 10 D. pteronyssinus was the most abundant species (71.4% and 45.8%). Housekeeping practices were investigated by interviewing the tenants and relative humidily and indoor/outdoor temperature were measured during each weekly sampling. A correlation analysis revealed a significant relationship between housekeeping practices and mite density (r = 0.83). The poorest housekeeping practices produced the heaviest mite infestation, while good ones were associated with low densities.

Temporal distribution of tick species was studied in the woodland "Macchia Grande" of Manziana in the province of Rome, Italy. A total of 2,494 ticks was collected by means of drag sampling during one year of survey (1993). Among the species identified, Ixodes ricinus (Linnaeus, 1758) (95.9%) was the most abundant, followed by Haemaphysalis inermis (Birula, 1895) (2.2%), Rhipicephalus bursa (Canestrini e Fanzago, 1877) (1.8%), Dermacentor marginatus Sulzer, 1776) (0.1%). I. ricinus was present during the whole year, showing a diphasic trend, with peaks in January-April (95-173 specimens per drag) and in November-December (29-126); H. inermis was recovered only during the cold season (January-April and in December) with the highest density in February (7); Rh. bursa was collected from May to October showing maximum occurrence in July (10). The presence of I. ricinus and H. inermis, proven vectors of Borrelia burgdorferi (Lyme disease) and TBE virus, is discussed in relation to the possible exposure risk for park visitors and operators.