PATTERNS IN THE DYNAMICS OF the FREQUENCY DISTRIBUTION OF NEMATODE ABUNDANCES IN BANK VOLE (CLETHRIONOMYS GLAREOLUS SCHREBER, 1780) Ieshko, E.
And Bugmyrin, S.
Institute of Biology, Karelian Research Centre RAS, Russia firstname.lastname@example.org There exists a variety of mechanisms in the nature which form the over dispersed (aggregated) distribution of parasites (Crofton, 1971; Boswell & Patil, 1970).
The two leading ones are differences in host susceptibility to infestation and variations in infestation dose due to spatial heterogeneity of the invasion agent’s distribution over the host’s habitats.
Some published sources and our data demonstrate that insignificant individual distinctions in host susceptibility lead to the formation of aggregated distribution in the host population, and the negative binomial distribution (NBD) is the most widespread model of parasite abundance there (Crofton, 1971; Breyev, 1972; Haukisalmi, 1986; Pavlov & Ieshko, 1986; Bugmyrin et al., 2005).
Long-term research in permanent sample plots showed bank vole in middle taiga to host 6 nematode species belonging to the families Capillaridae (Capillaria murissylvatici Diesing, 1851 (prevalence – 1.3%; abundance – 0.01 ind.)), Heligmosomatidae (Heligmosomum mixtum Schulz, 1954 (27.3; 0.85), Heligmosomoides glareoli Baylis, 1928 (13; 0.45), Longistriata minuta Dujardin, 1845 (3.1; 0.14), Syphaciidae (Syphacia petrusewiczi Bernard, 1966 (15.9; 12.2)), Spiruroidea (Agamospirura sp. (0.4; 0.01).
We found the distribution of abundances of the above species in the host population in different years and seasons, in different age and sex groups of bank vole to be distinctly aggregated. 18 TIME TO BE TRANSMITTED? – PLASTICITY IN HOST MANIPULATION BY A COMPLEX LIFE CYCLE PARASITE Benesh, D.
University of Jyväskylä, Department of Biological and Environmental Sciences, Finland email@example.com Complex life cycle parasites are faced with the fundamental problem of getting from one host to another.
As a solution, many parasites manipulate the phenotype of their hosts in ways which seem to increase the likelihood of successful transmission.
Examples of altered host phenotypes are numerous, but temporal variation in host manipulation, which could suggest changing costs and benefits associated with parasite transmission, is less well known.
Freshwater isopods infected with the acanthocephalan parasite Acanthocephalus lucii spend less time hiding than uninfected conspecifics.
I investigated whether this altered trait varies over time.
Over 8 weeks of laboratory observation, the difference between the hiding behavior of infected and uninfected isopods tended to increase.
Additionally, there were pronounced seasonal differences in the modification of host hiding behavior.
The difference between the behavior of infected and uninfected isopods was greatest in the spring, when both hosts and parasites are presumably older.
Isopods subjected to different light and temperature regimens, however, exhibited similar behavior.
This could suggest that seasonal changes in host manipulation depend more on host or parasite age than changing environmental conditions.
An increasing probability of host mortality, in addition to a decreasing potential for additional parasite growth, could favor increased host manipulation over time. THE EFFECT OF SEX AND AGE ON INTESTINAL PARASITE INFECTIONS OF FINNISH GROUSE Isomursu, M., Rätti, O., Helle, P.
And Hollmén, T.
Finnish Food Safety Authority, Animal Diseases and Food Safety Research, Oulu Research Unit, Finland Marja.Isomursu@evira.fi Sex and age of the host may influence the distribution of parasites as they affect host behaviour, body size, diet, preferred habitat and immune defence mechanism.
Physical sexual differences are particularly pronounced in polygynous grouse species.
We studied the occurrence of intestinal helminth parasites of three Finnish grouse species, capercaillie Tetrao urogallus, black grouse Tetrao tetrix and hazel grouse Bonasa bonasia.
The first two species are sexually dimorphic polygynous species while the latter is sexually monomorphic and monogamous.
The grouse harboured one species of nematodes (Ascaridia compar) and three species of cestodes (Skrjabinia (Raillietina) cesticillus, Paroniella (Raillietina) urogalli and Hymenolepis sp.).
We found a male-bias in the prevalence and abundance of A.compar which was most pronounced in the polygynous species.
The male-bias was larger in juvenile than in adult grouse.
In hazel grouse, there was a slight male-bias in the occurrence of ascarids, but no bias in abundance.
The occurrence of cestodes was not affected by host sex, but it was strongly dependent on age class: juvenile grouse were commonly infected while infections in adult were very rare.
Sexual difference in body size can be an important factor behind the sex-biased parasitism.
Differences in diet explain the age-dependent distribution of cestodes: insectivorous juveniles are more exposed to cestode larvae. 19 ANALYSIS OF THE CLEAVAGE PATTERN AND BLASTOMERES CHARACTERISTIC IN THE ANOPLOCEPHALID CESTODE MOSGOVOYIA CTENOIDES (RAILLIET, 1890) BEVERIDGE, 1978 Mlocicki, D.1, 2, Swiderski , Z.1, 3, Miquel, J.4and Eira, C4, 5 1 W.
Stefanski Institute of Parasitology, PAS, Warsaw, Poland; 2Dept.
Of Medical Biology, Medical University of Warsaw, Poland; 3Dept.
Of General Biology and Parasitology, Medical University of Warsaw, Poland; 4Laboratori de Parasitologia, Fac.
De Farmàcia, Universitat de Barcelona, Spain; 5Dept.
De Biologia, Universidade do Minho, Campus de Gualtar, Braga, Portugal; firstname.lastname@example.org The cleavage in Mosgovoyia ctenoides is unequal and has three types of blastomeres: 2 macromeres, 3 mesomeres and several micromeres.
Macromeres, the largest of the blastomeres, contain electron-dense granules, lipid droplets and mitochondria.
They also possess large nuclei with prominent nucleoli.
Cell divisions during cleavage were observed only in macromeres.
Mesomeres, the medium-sized blastomeres, are characterized by having lipid droplets, mitochondria and well-developed GER that is frequently adjacent to the nucleus.
Their nuclei contain electron-dense, spherical nucleoli.
Both macromeres and mesomeres are involved in the formation of the oncospheral envelope and are therefore excluded from further development of the haxacanth, which is produced by micromere differentiation.
Micromeres are the smallest and most numerous of the blastomeres.
They are free of any inclusion and are characterized by the highest N/C ratio.
Their spherical nucleus contains a small nucleolus and large heterochromatine islands.
Glycogen particles were most abundant in the macromere cytoplasm and lowest in micromeres.
During early development, as glycogen is distributed in other parts of the embryo, there is a simultaneous increase in the number of lipid droplets.
With further development, however, there is a progressive reduction of lipids, indicating that lipids may play a role as an energy source for the developing oncosphere. ENDEMIC UNICELLULAR INTESTINAL PARASITES (UIP) IN DENMARK Stensvold, C.R.
And Nielsen, H.V.
Laboratory of Parasitology, Dept.
Of Bacteriology, Mycology and Parasitology, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S.
Unicellular intestinal parasites (UIP) are responsible for approximately 95% of intestinal parasitic infections in Denmark, where diagnostic advances and growing epidemiological knowledge contribute to the understanding of the public health significance of UIP.
Whereas protozoa as eg Entamoeba histolytica, Giardia intestinalis and Cryptosporidium spp.
Have low prevalences in Denmark, little studied UIP such as Dientamoeba fragilis and Blastocystis sp.
Cause infection in 10-25% of patients suspected of intestinal parasitosis.
Blastocystis is a parasite of unresolved clinical significance, and most patients harbouring it are only treated if co-infected with a significant pathogen.
On-going studies including molecular characterisation of isolates from symptomatic and asymptomatic individuals are indicative of a potential relationship between Blastocystis subtype and clinical impact.In another study, Dientamoeba fragilis was detected in 12/103 patients by permanent staining of stool fixed in sodium acetate-acetic acid-formalin (SAF), whereas the parasite was not diagnosed by a formol ethyl-acetate concentration technique.
Only in 2/12 cases D.
Fragilis was seen in co-infection with an acknowledged significant pathogen.
This means that in Denmark at least 8/10 cases of curable, potentially symptomatic parasitosis go undetected using conventional diagnostic techniques.
It is essential to use suitable parasitological and molecular techniques to make exhaustive characterisations of UIP parasites recovered from patients and healthy individuals. 20 NEOSPORA CANINUM INFECTION IN MAN? Umran1, Stensvold, R.1, Vestergaard, L.2 and Nielsen, H.V.1 1 Laboratory of Parasitology, 2 Department for Epidemiology, Statens Serum Institut, Denmark.
Neospora caninum is a unicellular protozoan parasite that causes abortions in cattle and canines as the definitive host.
Caninum is closely related to Toxoplasma gondii with the felines as the definitive host and the cause of abortions in ie sheep, goat and humans.
A few papers describe cases of human infected with N.
Still is it debatable if N.
Caninum is capable of establish an infection in human.
In this study app. 300 Danish and 300 Tanzanian humans were investigated for the present of antibodies against the two parasites, examined by ELISA and Western blot techniques.comparison of possible mono- and double infected individuals will be discussed at the meting. MOLECULAR IDENTIFICATION OF EQUINE CYATHOSTOMES RESISTANT TO FENBENDAZOLE AND SUSCEPTIBLE TO OXIBENDAZOLE AND MOXIDECTIN
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