ABSTRACT
The ixodid tick Dermacentor marginatus (Sulzer, 1776) is endemic throughout southern Europe in the range of 33-51 (°) N latitude. In Germany, however, D. marginatus was exclusively reported in the Rhine valley and adjacent areas. Its northern distribution limit near Giessen is located at the coordinates 8.32 (°) E/50.65 (°) N. Particularly with regard to the causative agents of rickettsioses, tularemia, and Q fever, the observed locations as well as the potential distribution of the vector D. marginatus in Germany are of special interest. Applying a dataset of 118 georeferenced tick locations, the ecological niche for D. marginatus was calculated. It is described by six climate parameters based on temperature and relative humidity and another six environmental parameters including land cover classes and altitude. The final ecological niche is determined by the frequency distributions of these 12 parameters at the tick locations. Main parameters are the mean annual temperature (frequency distribution characterized by the minimum, median, and maximum of 6.1, 9.9, and 12.2 (°)C), the mean annual relative humidity (73.7, 76.7, and 80.9 %), as well as the altitude (87, 240, 1108 m). The climate and environmental niche is used to estimate the habitat suitability of D. marginatus in Germany by applying the BIOCLIM model. Finally, the potential spatial distribution of D. marginatus was calculated and mapped by determining an optimal threshold value of the suitability index, i.e., the maximum of sensitivity and specificity (Youden index). The model performance is expressed by AUC = 0.91.
Subject(s)
Dermacentor/physiology , Q Fever/epidemiology , Rickettsia Infections/epidemiology , Tick-Borne Diseases/epidemiology , Tularemia/epidemiology , Altitude , Animals , Climate , Ecology , Ecosystem , Environment , Female , Geography , Germany/epidemiology , Male , Q Fever/microbiology , Q Fever/parasitology , Rickettsia Infections/microbiology , Rickettsia Infections/parasitology , Temperature , Tick-Borne Diseases/microbiology , Tick-Borne Diseases/parasitology , Tularemia/microbiology , Tularemia/parasitologyABSTRACT
Outbreaks of Q fever are rare in the UK. In 2006, the largest outbreak of Q fever in Scotland occurred at a co-located slaughterhouse and cutting plant with 110 cases. Preliminary investigations pointed to the sheep lairage being the potential source of exposure to the infective agent. A retrospective cohort study was carried out among workers along with environmental sampling to guide public health interventions. A total of 179 individuals were interviewed of whom 66 (37%) were migrant workers. Seventy-five (41.9%) were serologically confirmed cases. Passing through a walkway situated next to the sheep lairage, a nearby stores area, and being male were independently associated with being serologically positive for Q fever. The large proportion of migrant workers infected presented a significant logistical problem during outbreak investigation and follow up. The topic of vaccination against Q fever for slaughterhouse workers is contentious out with Australasia, but this outbreak highlights important occupational health issues.
Subject(s)
Abattoirs , Coxiella burnetii/isolation & purification , Disease Outbreaks , Occupational Diseases/epidemiology , Q Fever/epidemiology , Transients and Migrants , Adult , Animals , Antibodies, Bacterial/blood , Cohort Studies , Coxiella burnetii/immunology , Data Collection , Female , Humans , Incidence , Logistic Models , Male , Middle Aged , Q Fever/diagnosis , Q Fever/parasitology , Q Fever/transmission , Retrospective Studies , Risk Factors , Rural Population , Scotland/epidemiology , Seroepidemiologic Studies , Sheep , Young AdultABSTRACT
Laboratory animals (mice and guinea pigs) were infected with the isolates of Coxiella burnetii (Derrick, 1939) obtained from bovine milk (M18 and M35) and the ticks Ixodes ricinus (Linnaeus, 1758) and Dermacentor marginatus (Sulzer, 1776) (Kl3 and Kl6, respectively), and with the reference strain Nine Mile. Neither mortality nor lethality occurred with the mice. Antibody response in mice infected with isolates from milk was lower (1:16-512) than that from ticks (1:32-4096). Onset of seropositivity also occurred later - on the 10th day post-infection (p.i.) for M18 and M35 in comparison with the 7th day for Kl3 and Kl6. In guinea pigs, infection manifested by fever. The fever was less evident in guinea pigs infected with isolates from milk (39.5-40.1 degrees C) than in guinea pigs infected with isolates from ticks (39.5-40.6 degrees C). Partially engorged females of Dermacentor reticulatus (Fabricius, 1794) were inoculated with isolates M18 and Kl3. No differences in the multiplication of C. burnetii in haemocytes between these two isolates were ascertained.
Subject(s)
Coxiella burnetii/pathogenicity , Dermacentor/parasitology , Ixodes/parasitology , Milk/parasitology , Animals , Antibodies, Bacterial/biosynthesis , Cattle , Chick Embryo , Coxiella burnetii/immunology , Guinea Pigs , Host-Parasite Interactions/immunology , Mice , Q Fever/immunology , Q Fever/parasitology , VirulenceABSTRACT
The dog tick, Rhipicephalus sanguineus Latreille, 1806 (Acari: Ixodidae), is a public health problem since it is widely distributed in Italy and because of its role in the transmission of many pathogens to man and dog which is its preferred host. This review deals with the main aspects of the biology and ecology of Rh. sanguineus habitat, developmental time, distribution and seasonality, behaviour and vector competence. Moreover, the preminent role of Rh, sanguineus in the transmission of boutonneuse fever is discussed.
