Open Access
Access granted
Subscription Access
Vol 59, No 2 (2025)
Articles
Fleas (Siphonaptera) as vectors in natural plague foci worldwide: host-parasite relationships, faunistic and geographical analysis, epizootic significance
Abstract
The fauna of fleas in the world is currently known by 2162 species, of which 262 species (12.1%) from 6 families are found infected with plague in nature. Fleas of the families Hystrichopsyllidae (74 species), Ceratophillidae (69 species) and Leptopsyllidae (40 species) are most involved in the epizootic. Among all flea species found infected with the plague pathogen, only 64 (24%) are considered as the main plague vectors. The species distribution by families is as follows: Ceratophillidae – 24 species, Pulicidae – 18 species, Hystrichopsyllidae – 10, Leptopsyllidae – 8, Rhopalopsyllidae – 4. The flea Oropsylla silantiewi takes the leading position among all main plague vectors. The approximate number of plague natural foci in the world is at least 316. O. silantiewi acts as the main vector and keeper of infection in 59 natural foci of plague. In 41 natural foci, this species is the only main vector, ensuring the circulation of the pathogen without significant assistance of other flea species. No other flea species is so powerfully involved in the plague pathogen circulation in any region of the world. O. silantiewi is a specific parasite of marmots, whose origin is associated with the mountain steppes of Central Asia, where the center of origin of the plague microbe is probably located. From this territory, the plague microbe began its further worldwide spread with penetration and development of new ecological niches in flea’s populations of ground squirrels, mice, rats, voles and other small mammals.
91-156
Seasonal dynamics of infection of the ide Leuciscus idus with metacercariae of trematodes of the family Opisthorchiidae and its relation with water level fluctuation
Abstract
The seasonal variability of the infection of the ide Leuciscus idus with metacercariae of the Opisthorchidae family in the Upper Ob basin was studied. Seasonal indices of the extensiveness of invasion (EI) varied significantly – from 18 to 72%, but average annual values were proportionate, staying within 43–46%. A trend of decreasing in the intensity of invasion in spring months compared to the summer-autumn period by an average of 20% for all years of the study (2012–2016) is evident. A negative correlation between the intensity of invasion (II) of fish and the water level during the cercariae emission period, r = –0.83 was found. Three main hypotheses were put forward to explain the decrease in fish invasion during the freeze-up period. The first two of them suggest a relatively high elimination of metacercariae in the winter months: either under the influence of low water temperature or hypoxia formed under the ice cover. The third of them is based on the assumption of the death of physiologically weakened infected fish as a result of hypothermia and asphyxia in wintering conditions.
157-171
Factors affecting the establishment of dengue fever vectors: a graphical model
Abstract
A graphical model provides a visual representation of the complex interplay between various variables that influence a factor. This communication demonstrates the use of graphical form for the analysis of factors affecting dengue fever vectors. A graphical model of the factors affecting the establishment of dengue fever vectors including environmental and human factors such as a lack of awareness and movement between regions, socioeconomic factors like poverty and limited access to healthcare facilities and climate change, as well as globalization and international travel was designed and drawn using features of the Shape and SmartArt graphic menu of the Word software.
172-176