Archive

The aim of the study was to reveal the differential effect of light and temperature on the regulation of daily cercarial emergency of littoral trematodes transmitted in the subarctic White Sea (66°20' N, 33°38' E) and the Lake Chudskoe (58°13' N, 27°31' E) from their molluscan hosts. Cercariae of 10 species of marine trematodes - Cryptocotyle lingua, C. concava (Heterophyidae), Himasthla elongata, H. continua (Himastlidae), Cercaria parvicaudata (Renicolidae), Levinseniella brachysoma, Maritrema subdolum, Microphallus claviformis, M. similis (Microphallidae), Paramonostomum alveatum (Notocotylidae) and two freshwater species - Diplostomum pseudospathaceum (Diplostomidae) and Moliniella anceps (Echinostomatidae) were involved in the study. A short-term (2 h) effect of darkness and illumination (800 lux) and temperature (10, 20, and 25 °C) on the intensity of cercarial emergency from the infested molluscan hosts has been tested. The experimental setup and scheme of experiments allowed separating the influence of the investigated factors of all gradations. The results of the experiments showed that light played a significant role only in the stimulation of emergency of cercariae with pigment eyespots and for which the presence of non-pigmented photoreceptors was assumed. However, the emergency of these larvae was temperature-controlled in the darkness, and in Himasthla spp. this factor was more significant than light. For all other cercariae, including D. pseudospathaceum larvae with non-pigmented photoreceptors, the emergence rate was almost completely controlled by temperature with minimal contribution of light in regulation of this process. Statistically reliable significance of interaction of factors of temperature and illumination in regulation of cercarial emergency was revealed virtually for all studied species. Illumination had an inhibitory effect on the emergency of C. parvicaudata, L. brachysoma and M. similis cercariae, whose daily emergency maximum under natural conditions was timed to twilight hours. In combination with a temperature close to the supra-optimal for cercarial emergency, light reduced its intensity in H. elongata and a number of larvae without photoreceptors. The temperature dependence of the rhythm and intensity of the daily cercarial output is particularly important in polar latitudes, where a significant part of the seasonal 'transmission window' for trematodes falls on the period of polar day with minor daily changes in illumination.

The high prevalence of intestinal helminth infections among children living in developing countries impairs growth in these populations. Present study was aimed at comparing the nutritional status of children infected by soil-transmitted helminths (STH) with that of uninfected children. Stool samples and anthropometric measurements were taken from 382 children. Stool samples were processed by using both simple smear and zinc sulphate concentration methods. Nutritional status was assessed by Waterlow classification. Of the 382 children surveyed, 78.27 % were infected with either Ascaris lumbricoides or Trichuris trichiura, or both. Children infected with STH were found to be more malnourished than uninfected children. The present study concludes that soil-transmitted helminths are abundant among school children of Kashmir valley, with negative impact on their nutritional status.

Taxonomic diversity, peculiarities of distribution, and host-parasite relations of fleas of the Holarctic genus Rhadinopsylla (Hystrichopsyllidae: Rhadinopsyllinae) were analyzed. The role of some representatives of this genus as vectors and reservoirs in natural plague foci of Eurasia was considered. It has been shown that 18 out of 70 flea species and subspecies of the genus Rhadinopsylla were mentioned as main, secondary, or occasional vectors of this infection.

The territory of the Russian Federation harbors a wide range of habitats with different breeding site conditions for arthropods across its territory. Many geographical regions have never been entomologically studied, which leaves uncertainty as to epidemiological risks should a vector-borne diseases occur there. In this paper for the first time the seasonal indoor and outdoor activities of farm-associated Culicoides biting midges in three climatically diverse regions of Russia are examined: Crimea (South), Buryatiya republic (Eastern Siberia) and Smolenskaya province (Central Russia). The results indicate that species composition and abundance differ greatly in the three provinces due to temperature and moisture availability. COI barcoding suggests a great genetic variation among the morphologically identified Culicoides species.

Insecticide resistance is a worldwide menace in the control of vector borne diseases evolving in substantial vector control program. Cytochrome P450s including CYP6M2 is known to be involved in the metabolism of insecticides preceding resistance. Information on regulatory mechanisms involved in the control of P450s in Anopheles gambiae Giles, 1902 is not yet clear. In this review, we analyze the potential function of Nuclear factor erythroid factor 2 (Nf2e 1), which is an ortholog to Nuclear factor E2-related factor 2 (Nrf2) in vertebrates and Cap 'n' collar isoform C (CnCC) in Drosophila melanogaster in the countenance of the expression of CYP6M2 gene encoding enzymes and conceivably to alienate insecticide resistance in the control of Anopheles gambiae. Under normal conditions, Nf2e1 aggregates in the cytoplasm where it synergizes with the actin binding protein, Kelch-like ECH associating protein 1 (Keap1) ortholog AGAP003645, and is instantaneously degenerated by the ubiquitin-proteasome pathway. This review article depicts contemporary knowledge of the Nf2e1/ AGAP003645 complex, consolidating chiefly on the molecular mechanism of Nf2e1 regulation and its potential implication in the control of mosquito borne diseases including malaria.

In the paper, a complex of functional systems in the organisms of parasitengona mites, such as mouth apparatus, proterosomal salivary glands, digestive system, excretory and osmoregulatory systems, nervous system and sense organs, important in the realization of their life strategy is considered from the position of their contribution in the successive feeding process and parasitism. The joint action of these complex factors on the host organism results in its corresponding functional, in particular, tissue reaction that together leads to the effective feeding. Parasitengonina mites being a highly diverse and specialized phyletic lineage of the higher Acariformes, possess at the same time small and simply organized larvae. Nevertheless, these larvae show a highly effective feeding mode of the power-effective proteinaceous feeding substrate consisting of the extra-intestinally digested host tissues. This capability is a result of the stylostome formation and allows larvae to overcome easily a high ontogenetic threshold between the larval organization and that of the postlarval phases of the life cycle. Such ontogenetic jump appears to be impossible for many other groups of Acariformes with another, separated and short-time feeding mode. Moreover, the necessity of the long-time feeding is strongly defined by the larval morphology that, in turn, predetermines stylostome formation different in different parasitengonina groups.