Immune response in rabbits experimentally infected with Ascaris suum

Immune response of rabbits experimentally infected with Ascaris suum was studied by indirect haemagglutination method. The animals were infected with the doses of 5,000, 10,000 and 20,000 infective eggs per animal. Positive reactions were observed from days 5-11 p.i., maximum reactions on days 11-19 p.i. A reinfection with the same doses (1x or 2x after 35 and 65 days) increased the antibody titre. The strongest individual reaction was recorded on day 19 p.i. in the group infected with the highest dose (titre 1 : 4096). The increased antibody titres persisted til the end of the experiment (82th day p.i.) in all groups.     

Morphological, developmental and ecological evidence for a progenetic life cycle in Neochasmus (Digenea)

Seven species of fishes, Catostomus commersonii (Lacépède), Etheostoma nigrum Rafinesque, Micropterus dolomieu Lacépède, Notemigonus crysoleucas (Mitchill), Notropis hudsonius (Clinton), Perca flavescens (Mitchill), and Percina caprodes (Rafinesque) from the St. Lawrence River, Quebec, Canada, were found infected with progenetic specimens of Neochasmus spp. in the orbits and/or the body musculature. Worms displayed varying degrees of maturation. Eggs occupied the entirety of the worm in late stages of development and persisted as distinct clusters in situ after worm death. Populations of parasites were studied monthly in E. nigrum from one site between May and October in order to follow parasite recruitment, development and maturation. Recruitment of parasites was observed in young-of-the-year fish primarily in July and continued through October. Worms matured rapidly, displaying egg production within a month. Later developmental stages, in which eggs occupied most of the worm, and clusters of eggs became abundant by September. Infections in overwintered fish collected in May consisted mainly of worms in early stages of egg production and of clusters of eggs. When hatched artificially, eggs from the clusters released viable miracidia, indicating that they survive beyond the lifespan of the adult worm. It is suggested that progenesis is a fixed characteristic of the life cycle of these species, that egg dispersal requires the death of the host and that it is facilitated by predation. All prior records of Neochasmus spp. are examined, leading us to conclude that the role of the putative definitive host (primarily basses) has been reduced to that of a dispersal agent. Current hypotheses concerning the evolution and maintenance of progenesis are considered, but it is concluded that they do not apply to this host-parasite system.     

The life cycle of Echinostoma bolschewense (Kotova, 1939) (Trematoda: Echinostomatidae)

The life cycle of E. bolschewense, the species with 37 collar spines and closely related to E. revolutum, was experimentally studied. The following developmental stages are described: mother and daughter rediae, cercaria, metacercaria, and adult. The freshwater prosobranchiate snail Viviparus contectus was found to be the first intermediate host in nature. Under experimental conditions, the miracidia developed in V. contectus. They did not, however, penetrate into Bithynia tentaculata or into any of the pulmonate snails tested. The cercariae encysted in various Prosobranchia and Pulmonata. Adult worms were commonly obtained from hamsters (Mesocricetus auratus) and only exceptionally from chickens (Gallus gallus f. dom.). The species studied is considered to be conspecific with Cercaria bolschewensis described by Kotova (1939).     

Studies on the development of the cestode Proteocephalus neglectus La Rue, 1911 (Cestoda: Proteocephalidae) under experimental conditions

A part of the life cycle of Proteocephalus neglectus La Rue, 1911, a parasite of trout, starting from release of eggs from mature parasites into water, to the early phase of development in the definitive host, was studied under experimental conditions. Special regard has been paid to development in the intermediate host, copepod Cyclops strenuus. Some oncospheres in eggs kept in water at 5 and 10 degrees C remained infective for 20-25 days. The percentage of infected copepods depended on the length of their contact with parasite eggs. Cestode larvae (cercoscoleces) were formed in the intermediate host on days 8-10 p.i. at the temperatures of 21-22 degrees C, on days 18-21 at 15 degrees C, on days 24-28 at 10 degrees C, and on days 59-65 at 6 degrees C. Most larvae, including infective cercoscoleces, were localized in the cephalothorax of the intermediate host, particularly in its first segment. This localization did not change during their development. The infectivity of cercoscoleces was verified by experimental infection of Salmo gairdneri fry. The development of the cestode in this definitive host was observed for 17 days after infection at 10 degrees C. The finding of P. neglectus cereoscoleces in fish of the families Cottidae and Cyprinidae on day 2 after experimental infection indicates that these larvae can survive for a short time in atypical fish hosts.     

Data on the morphology of the nematode Spinitectus minor (Stewart, 1914) (Nematoda: Cystidicolidae)

Morphology of the nematode Spinitectus minor harboured by Mastacembelus armatus from Burdwan, West Bengal, India was studied by light and scanning electron microscopes. The worms were described, illustrated and discussed taking into consideration of the information available relative to this species. Alate spicules, polar caps on the eggs and prodelphic uteri are clearly seen in the present LM studies and SEM photomicrographs provided detailed information about the microtopography of the worms.     

Teratogenic effects of the fungicide benomyl on posterior segmental regeneration in the earthworm,Eisenia fetida

Earthworms, Eisenia fetida, were treated by surface exposure to the fungicide benomyl at various stages of posterior segmental regeneration. Teratogenic effects of benomyl were observed when worms were treated 7–11 days after amputation (i.e. during the normal period of segmental replication), but not during days 1–5, 13–17, or 19–23. Teratogenic effects included a reduction in the number of regenerated segments, an increased frequency of segmental groove anomalies, and a variety of monstrosities. The effects of benomyl treatment on the number of regenerated segments and frequency of anomalies were dose-dependent within a narrow concentration range (approximately 0.2–5.0 mg litre^?1); at higher concentrations (e.g. 25 mg litre^?1) teratogenic effects were less frequent because the onset of segmental delineation was delayed until well after exposure. Non-invasive electrophysiological recordings from treated worms indicated that functional integrity of giant nerve fibre conduction pathways was established in all anomalously regenerated tail segments, except in a two-tailed monstrosity. The evidence supports the hypothesis that these teratogenic effects derive from an antimitotic mode of action of benomyl on segmental regeneration.     

Observations on the bionomy of Allocreadium isoporum (Looss, 1894) (Trematoda: Allocreadiidae).

From October 1985 until July 1987, the bionomy of the trematode Allocreadium isoporum (Looss, 1894) was studied in the Rokytná River (the Danube basin), Czechoslovakia. While clams of the genera Sphaerium Scopoli and Pisidium Pfeiffer apparently serve as its first intermediate hosts, mayfly larvae Ephemera danica Müll. were found (prevalence 8%, intensity 1-5 metacercariae per mayfly) to be the only second intermediate host of A. isoporum in the locality. The most important definitive host is chub, Leuciscus cephalus (L.), in which the seasonal dynamics of A. isoporum occurrence and maturation was followed. The parasite exhibits here a distinct seasonal cycle of maturation which is shown mainly by quantitative changes in the ratio of young to mature worms containing eggs. The trematodes containing eggs occur almost throughout the year, but mainly in the spring and early summer (maximum in May), and after the oviposition they leave the host. New infections are acquired by chub all the year round. This seasonal periodicity is determined by ecological factors, mainly the temperature regime in the locality. A isoporum infections in chub in this locality are dependent on the body size of host fishes; the highest degree of A. isoporum infection occurs in fishes 20-25 cm long, the prevalence decreasing somewhat in larger fishes; infection is associated with changes in the food composition of chub of different size groups.     

The ecology of Crepidostomum species (Allocreadiidae: Digenea) in the salmonoids of Lake Yli-Kitka in northeastern Finland

Crepidostomum spp. were studied from 417 whitefish (Coregonus acronius Rapp, 1854), 220 vendace (Coregonus albula L.) and 38 brown trout (Salmo trutta m. lacustris (L.)) from Lake Yli-Kitka in northeastern Finland during 1980-1983.12.7% of the whitefish were infected with Crepidostomum with a mean intensity of 4.6 worms per infected fish. The species involvedare C. farionis (Müller, 1784) and Crepidostomum wikgreni Gibson et Valtonen, 1988, which differed from C. farionis in the number and size of the eggs. Both types were encountered in the gall-bladder and intestine, but were unable to be distinguished as immature stages. 21% of the brown trout harboured C. farionis in the intestine with a mean number of 1.5 worms per infected fish. Two C. farionis specimens occurred also in the intestine of one vendace. Whitefish smaller than 150 mm did not harbour Crepidostomum specimens, but in bigger fish the prevalence and the mean intensity of infection increased to a certain limit as the fish got larger. The prevalence of Crepidostomum infection also clearly increased during the three seasons in the three size-groups studied. The seasonal pattern of Crepidostomum in whitefish of the size greater than or equal to 150 mm was variable in that the lowest values, both in the prevalence and mean intensity of infection, occurred between September and December in 1980 and between April and August in 1982. Reinvasion was found throughout the year, although the main recruitment occurred during autumn and early winter. Eggs matured between late spring and early autumn. The smallest worms occurred mainly in the gall-bladder, and most of the gravid specimens were located in the intestine. Both the variance-to-mean ratio and the low values of the parameter k of the fitted negative binomial distribution reveal the Crepidostomum specimens are overdispersed in the whitefish of Lake Yli-Kitka.     

The life cycle of Dichelyne (Cucullanellus) minutus (Nematoda: Cucullanidae)

Mature specimens of the nematode Dichelyne (Cucullanellus) minutus (Rudolphi, 1819) (Ascaridida, Cucullanidae, Seuratoidea) were obtained from the intestine of flounder Platichthys flesus (L.) caught in the Oresund, Denmark. Plaice Pleuronectes platessa L. and common goby Pomatoschistus microps (Kr?yer) also harbour this species. The eggs embryonate on the seabottom. Larvae about 440 microm long, and believed to be in their third stage, hatch from the eggs. These larvae are not directly infective to flounders or gobies. The polychaete Nereis diversicolor O.F. Muller acts as obligatory intermediate host. Experimental infections showed that larvae >600 microm long and provided with achitinous tooth survived in flounder and common goby. The third-stage larvae moult to fourth-stage larvae in the fish gut wall. Mature worms occur in the lumen of the anterior part of the intestine. All developmental stages may be transferred from one flounder to another; thus the flounder may acquire the parasite also by devouring infected gobies.     

Pathological and biochemical changes in Brassica juncea (mustard) infected with Albugo candida (white rust)

Components of disease reaction, including incubation period, pustule types, inoculum production and disease index (DI); and contents of protein, phenols, soluble sugars and reducing and non-reducing sugars were investigated in cotyledonary and true leaves of six genotypes of Brassica juncea : Varuna, Kranti, EC-399296, EC-399299, EC-399313 and EC-399301, inoculated with Albugo candida . Cotyledonary leaves were examined 14 days after inoculation (d.a.i.), whereas true leaves were scored 14 and 21 d.a.i. Disease indices were assessed on a 0% (resistant) to 100% (susceptible) scale. DIs at the cotyledonary leaf stage in the above six genotypes were 67, 65, 32, 31, 31 and 38%, respectively, whereas at the true-leaf stage they were 21, 28, 12, 17, 9 and 4%, respectively at 14 d.a.i., and 35, 45, 17, 19, 20 and 6%, respectively at 21 d.a.i. Protein contents were highest in the genotypes with the highest DIs, such as Varuna at the cotyledonary leaf stage and Kranti at the true-leaf stage, and lowest in the genotypes with the lowest DIs, such as EC-399299 at the cotyledonary stage and EC-399301 at the true-leaf stage. Total phenols, total sugars, reducing sugars and non-reducing sugars were generally negatively correlated with DI, but were not always consistent, particularly when differences in DI were small. The results indicated that factors conditioning the response of host genotypes to A. candida may differ or operate in different ways at different growth stages.     

The ovicidal properties of the juvenile hormone mimic sumitomo S-31183 (SK-591) to insects

S-31183 was assayed against preimaginal stages of the tobacco whitefly,Bemisia tabaci (Genn.), and eggs of the Egyptian cotton leafworm,Spodoptera littoralis (Boisd.). The compound was found to be an ovicide forB. tabaci eggs in both preinfestation and postinfestation treatments. FreshS. littoralis eggs were very susceptible to the compound at 0.05 ppm a.i., response was much poorer with 1-2-day-old eggs and 2-3-day-old eggs were not affected even by 100 ppm. Publication of the Agricultural Research Organization. No. 2271-E, 1988 series.     

Experimental infection of Atlantic salmon (Salmo salar) with marine Eubothrium sp. (Cestoda: Pseudophyllidea): observations on the life cycle, aspects of development and growth of the parasite.

The life cycle of marine Eubothrium sp. (Cestoda: Pseudophyllidea), from Atlantic salmon (Salmo salar L.) was experimentally completed in one year and included only one intermediate host (Acartia tonsa Dana) (Copepoda: Calanoida). Adult cestodes were collected from farmed salmon, and ripe eggs released by the cestodes were fed to Acartia tonsa. Ingested eggs hatched in the gut and the larvae developed in the haemocoel of the copepod for 15 days at 16 degrees C. A total of 170 seawater-reared salmon were exposed to infected copepods and the total prevalence of Eubothrium sp. in the salmon after infection was 95.3%, with a mean intensity of 15.0 (range 1-87). The infected salmon were kept in the laboratory where the growth of the cestodes was studied for eleven months. Mean length of the cestodes increased with time, but a large variation among the cestodes was observed. Growth and maturation of the cestodes were dependent on host size and the number of worms present in the intestine. No evidence of mortality of Eubothrium sp. was observed during the experimental period.     

食物对荔枝蝽生殖和存活的影响

食物显著地影响荔枝蝽的卵巢发育,产卵量和成虫的产卵期寿命,罩养于支树花（果）枝上,荔枝蝽每雌平均产卵２２２．３粒,净增殖率为１１０．５７;雌、雄成虫的平均寿命分别为９６．２５和９３．１９ｄ。罩养于嫩枝上者,每雌平均产卵１９３．４ ,净增殖率为９６．２６;雌、雄成虫的平均寿命分别为８９．６９和８９．２５ｄ。罩养于老枝上的成虫不能产卵,雌,雄成虫的平均寿命分别为７０．４４和７０．３１ｄ。在花（果）枝上     

Tissue reaction after subcutaneous injection of Taenia saginata oncospheres

After subcutaneous injection of T. saginata oncospheres, a slight swelling is visible at the site of injection first after 13 days. Conspicuous projecting nodes appear after 3-4 weeks. Histological examinations of the site of injection revealed the following changes: On days 3 and 4 p.i.--edema, focal necrosis and haemorrhage, exudation of leukocytes, activation of monocytes and fibroblasts. On day 7 p.i.--in addition to edema and foci of eosinophiles, a striking activation of monocytes and fibroblasts, focal accumulation of macrophages, proliferation of blood capillaries and formation of collagen. On day 10 p.i.--eosinophiles and light macrophages around the larvae, fibroplastic granulation tissue at the periphery and collagenous connective tissue abundant. Hyperplasia of lymphoid tissue starts to appear at this time. On days 13-14 p.i.--a large amount of newly formed connective tissue in granulation tissue, diffuse infiltration of eosinophiles and hyperplasia of lymphatic tissue. On days 19-34 p.i.--haemorrhage around the cysticerci, activation of macrophages, phagocytizing erythrocytes. Endothelia of blood capillaries proliferate; lymphatic follicles are formed at the periphery of nodular affection which appears after inoculation of oncospheres. On day 34 p.i.--distinct formation of a pseudocyst. At the period from 53th to 61st day after injection, there is a mature collagenous connective tissue among the cysts, but still strongly infiltrated with cells. Clusters of siderophages are visible in connective tissue septa between the cysts.     

拟澳洲赤眼蜂对小菜蛾卵的适应能力

本文比较经米蛾卵繁殖的拟澳洲赤眼蜂在小菜蛾卵和米蛾卵上的产卵差别，结果为：不喂蜜糖水，拟澳洲赤眼蜂寿命短，不到一天，可在小菜蛾卵上产卵的雌蜂比 只有４５．４５％，比可在米蛾卵上产卵的雌蜂比例低得多，可产卵雌蜂的平均产卵量亦是在小菜蛾卵上的低，喂以蜜糖水，拟澳洲赤眼寿命得以延长，平均寿命达１２天以上，可在小菜蛾卵上产卵的雌蜂比例为９６．１３％，与可在米蛾卵上产卵的雌蜂比例相当，并且在两种寄主卵上可产     

Histopathological changes in the liver tissue of house mouse and common vole during sarcocytosis

The asexual reproduction of Sarcocystis dispersa was studied in the liver of the house mouse. Histopathological examinations revealed infection of parenchymal cells with the parasite and diffuse cellular infiltrations with the presence of polymorphonuclear cells, monocytes and eosinophilic leukocytes. The volume and number of cellular infiltrates increased gradually from day 3 till day 10 p.i. Then appeared necrotic foci and both phenomena reached the maximum on days 10-12 p.i. On days 21-34 p.i., no changes occurred in the tissue and the liver healed without scars. The infection of common vole with Sarcocystis cernae sporocysts caused cellular infiltrations in the liver around the portobiliary veins. The parasite was present from day 3 till day 7 p.i. The histopathological picture of liver changes was similar to that in the house mouse.     

Laboratory studies on the influence of the earthworm Eukerria saltensis (Beddard) (Oligochaeta: Ocnerodrilidae) on overlying water quality and rice plant establishment

Dense infestations of a peregrine oligochaete worm, Eukerria saltensis (Beddard), have been linked to rice crop failures in southern New South Wales, Australia. The influence of E. saltensis on water quality and rice plant establishment was investigated in a series of laboratory experiments using a flooded Riverina clay soil. Worm densities of 20 and 40 per container (2548 and 5096 worms/m², respectively) significantly increased water turbidity after 7 days incubation. Longer incubation periods led to turbidity levels of over 500 NTU being achieved (40 worms per container, 21 days incubation). Water pH was significantly reduced by densities of 10, 20, and 40 worms per container after 7 days under cyclical illumination, however in continuous darkness significant changes in pH related to worm density were only found after 21 days incubation. Nitrogen as NH₄+ and total phosphorus increased significantly in the overlying water in response to increasing worm densities after 21 days incubation, however nitrogen as nitrate/nitrite and soluble phosphorus did not. Algal production (measured as extracted chlorophyll a concentration) was unaffected by the worms, reflecting the low concentrations of available phosphorus in all treatments. Rice plants grown in containers with worms produced significantly longer and heavier shoots than control plants. Root systems were unaffected, and there was no evidence of root abrasion. Evaluation of rice seed stratification in the soil profile indicates that rice seeds can be passively transported below the soil surface by the feeding and tunnelling activity of E. saltensis. Our results suggest that E. saltensis impedes the establishment of aerially-sown rice crops primarily by increasing water turbidity. Plants respond to high turbidity by partitioning more of their growth into shoot production, and consequently become vulnerable touprooting through wave action, particularly as the soil loses compaction because of worm activity. Maintaining the lowest possible water levels during rice crop establishment has helped farmers to minimize these effects.     

Effect of pulp and paper mill effluent (BKME) on physiological parameters of roach (Rutilus rutilus) infected by the digenean Rhipidocotyle fennica

Physiological parameters were measured after experimental infection of roach (Rutilus rutilus L.) with Rhipidocotyle fennica Gibson, Valtonen et Taskinen, 1992 (Digenea) cercariae. The fish were caught from two lakes: a eutrophic bleached kraft mill effluent (BKME)-contaminated lake and an oligotrophic unpolluted lake. The intensity of infection was followed up to 10 days post infection (p.i.) and physiological parameters indicating non-specific stress responses and the condition of fish were examined simultaneously. The mean abundance, the number of parasites per fish, of R. fennica was significantly higher in the fish from the contaminated water during the first two days p.i., probably reflecting the decreased resistance of these fish to infection. The decrease of leukocrit, as well as the increase of the activity of transaminases (GOT and GPT) in infected fish of both groups are suggestive of pathological processes caused by cercariae penetrating the fish. A significantly lower leukocrit value, as well as higher alkaline phosphatase activity and plasma chloride levels were noted in fish originating from the contaminated lake compared to those from the unpolluted lake. No significant differences were noted in haematocrit, plasma protein and calcium values between the fish from the uncontaminated and contaminated lakes, or between the infected and uninfected control fish.     

Zur Kenntnis der Blattminen-MotteCameraria ohridella Desch. & Dim. (Lep., Lithocolletidae) anAesculus hippocastanum L. in der Tschenchischen Republik

Cameraria ohridella was recorded first in 1985 in Macedonia. It gradually expanded to north and west and at present it is a serious pest of Horse ChestnutAesculus hippocastanum in the Czech Republic, having been established at about 80 localities. There are 4–5 overlapping generations with sizes of the larvae of 0.4–4.0 mm. The larva develops inside the leaf tissue in the upper parenchym layer of the leaflet and causes a mine, the size of which is broadened with growing larva. First adults start to fly at the end of April. After mating the females lay single eggs on the leaves. Larval development lasts 25–30 days followed by the prepupa I and II. The latter spins a cocoon in which the pupa of the last generation hibernates. The development from L4 to the prepupa lasts for 3–6 days at 22°C. During the summer it is possible to find all larval and prepupal stages in attacked leaves. FourAesculus species:A. parviflora Walk,A. carnea Haey.,A. glabra Walk andA. indica J. Hobb. were found to be resistent toC. obridella. A. lutea H. J. was liftle andA. pavia L. was heavily attacked. The parasitization ofC. o. larvae was very low. Only 2 parasites were found in 1500 mines in the first and second generation ofC. o., and 40 parasites in 1000 mines of the fourth and fifth generation. The highest mortality takes place in moths, eggs and young larvae. It was found in all 4 generation that there were i. m. 50 eggs/leaflet from which i. m. 3 hibernating pupae resulted. Supposing 2 moths (1♀, 1♂)/leaflet emerged in spring which produced 50 eggs (75 eggs/♀—33% moth mortality), the density of eggs in the first generation after hibernating being the same as in the last (fourth) generation before hibernating. As to the whole populations density in this case we can calculate as following: 3 pupae/leaflet on the tree=3000 pupae/leaflets pro m² on the soil=2000 emerging moths pro m²=50,000 moths (25,000 ♀♀) pro tree (namely 25 m² projecting area of the tree crown×2000 moths).