Eimeria lancasterensis Joseph, 1969 and E. confusa Joseph, 1969 from the Grey Squirrel Sciurus carolinensis*

SYNOPSIS. Forty grey squirrels Sciurus carolinensis were examined for coccidia during a 2-year period. Eimeria lancasterensis was found in all of them. The ellipsoidal oocysts of this species averaged 24.6 by 14.6 μ. They had no micropyle or oocyst residuum. A polar body was present. The sporocysts averaged 14.1 by 8.4 μ. The endogenous phases of the parasite were found in the epithelial cells of the villi thru the entire length of the small intestine. E. confusa was found in one of 40 squirrels. The oocysts of this species were subspherical, occasionally ellipsoidal or rarely spherical; they averaged 33.2 by 26.7 μ. Oocyst residuum and micropyle were absent. Polar granules ranged in number from 0–5. The sporocysts averaged 19.6 by 12.1 μ. The prepatent period for this species was 7–8 days and the patent period 6–13 days. E. ontarioensis was found in 3 of the 40 squirrels.     

Distribution and status of the Red Squirrel (Sciurus vulgaris) and Grey Squirrel (Sciurus carolinensis) in Ireland

The distributions of the Red and Grey Squirrel were surveyed in Northern Ireland and the Republic of Ireland between 1994 and 1996. Survey methods differed between the two studies. In the former, all suitable habitat, of at least 15 ha, was inspected for species presence or absence. In the Republic, data were gathered through questionnaires to governmental and independent wildlife bodies. The combined results indicate that the Red Squirrel remains widespread and locally abundant, and is present in all but two counties. The Grey Squirrel is now more widespread than ever before, and can be found in 22 of the 32 counties. Its range expansion has varied from 0 km/yr to an estimated 13.4 km/yr, as various geographical features, principally rivers, have hindered its progress in certain directions.     

Eimeria ontarioensis n. sp., E. confusa Joseph, 1969 and Eimeria sp. (Protozoa: Eimeriidae) from the Ontario Gray Squirrel Sciurus carolinensis*

SYNOPSIS. Eimerians from 27 gray squirrels Sciurus carolinensis sampled in Waterloo County were studied. Two double-walled species, E. ontarioensis n. sp. which was piriform (36.8 × 23.5) and E. confusa Joseph which was subspherical (35.7 × 28.4), were described and compared with similar species from the genus Sciurus. Eimeria sp., ellipsoidal (24.9 × 14.4), from Ontario gray squirrels resembled E. ascotensis and E. neosciuri and was a new eimerian record from Ontario. The zoogeographic significance of E. ontarioensis n. sp. and E. sp. in North American gray squirrels is discussed.     

Eimeria malabaricas sp. n. and Eimeria bandipurensis from the South Indian Tree Squirrel,Funambulus tristriatus*

Synopsis. Oocysts of Eimeria malabaricas sp. n. and Eimeria bandipurensis from the South Indian tree squirrel Funambulus tristriatus collected in Kerala, India, are described. Sporulated oocysts of E. malabaricas were ellipsoid to subspherical measuring 39.8 (35–45) × 32.1 (29–37) m?m, with a thick (2.5–3.0 m?m), 2-layered wall. The outer layer was yellow-brown, striated, and rough. There was no micropyle. but a polar granule was present in 34% of oocysts. The sporocysts were ovoid, 16.0 (14.0–18.0) × 11.2 (11.0–12.0) m?m, with a Stieda body and a granular residuum. Excysted sporozoites were 21.8 (19.0–23.0) × 3.4 (3.0–4.0) m?m, with a large refractile body. The sporulated oocysts of E. bandipurensis are redescribed.     

Interspecific effects of grey squirrels (Sciurus carolinensis) on the space use and population demography of red squirrels (Sciurus vulgaris) in conifer plantations

Interspecific competition between red squirrels and grey squirrels was investigated by comparing the population demography, spacing behavior and habitat use of red squirrels in two large conifer plantations in northern England: one site had only red squirrels (the red-only site), in the other both red and grey squirrels occurred (the red–grey site). Despite more abundant food at the red–grey site, red squirrel densities (0.26 ha^–1 at the red–grey site, 0.29 ha^–1 at the red-only site), adult survival rates and the breeding rates of females were similar at both study sites. Grey squirrels at the red–grey site occurred at higher densities (0.92–1.1 ha^–1) than did the reds and tended to have higher breeding rates. In the presence of grey squirrels, the recruitment pattern of red squirrels changed and there was little recruitment of subadults. The juvenile recruitment rate in the red–grey site (13%) was much lower than in the red-only site (50%). Grey squirrels, in contrast, had higher juvenile recruitment rates at the red–grey site (41%). The core areas of the home ranges of red squirrels in the red–grey site were more strongly overlapped by grey squirrels than by conspecifics. Red squirrels did not select the habitat with the best tree seed crop (Scots pine) but preferred dense Sitka spruce plantations; they appeared to avoid the Scots pine area with its high grey squirrel density. Data on foot length and body condition indicated decreased body growth in young red squirrels when grey squirrels were present. Our data suggest that adult red squirrels suffered little from interspecific competition with grey squirrels and that the key factor is decreased juvenile recruitment in red squirrels.     

Modelling the Expansion of a Grey Squirrel population: Implications for Squirrel Control

A recently discovered population of the North American grey squirrel (Sciurus carolinensis), introduced to Ticino Park, Lombardy (N Italy), is likely to spread into continuous prealpine broadleaf forests of Lombardy and the south of Switzerland. We used Spatially Explicit Population Dynamics Models (SEPMs), successfully used to predict the spread of grey squirrels in England and Piedmont, Italy, to examine the effects of different control scenarios on grey squirrel expansion in a 20000 km² area around Ticino Park. Without control, grey squirrels will invade Switzerland within the next two decades, and, concomitantly, the size and distribution of local populations of native red squirrels will be reduced. Simulating different grey squirrel control or removal scenarios suggests that: (i) efficient control is possible and mainly determined by the spatial distribution and woodland size of the ‘target’ control areas; and (ii) immediate actions must be taken, since delay in grey squirrel control will result in the population increasing and spreading, which makes the problems of successful containment more difficult. Model scenarios were based on surveys that may underestimate the real distribution range and current population size of grey squirrels. Therefore, a combination of hair–tube monitoring and a public participation survey to detect grey squirrel presence, which may also help to increase public awareness, is recommended. Successful containment of further grey squirrel spread will require local co-operation between Italian and Swiss authorities involved in wildlife management.     

A simple method for isolation of microsatellites from the Japanese squirrel,Sciurus lis,without constructing a genomic library

We developed a simple and easy method to isolate microsatellites without screening genomic libraries by hybridization. The method requires only three basic techniques: polymerase chain reaction, DNA cloning and sequencing. We applied this method to develop microsatellite markers for the Japanese squirrel and isolated 45 clones that contained repetitive sequences. Among the 22 clones that we tested further, we found 11 diagnostic microsatellite loci that are applicable to the molecular ecological study of Japanese squirrels.     

Fine Structure of the Endogenous Stages of Eimeria labbeana. 5. Schizonts and Merogony,with Special Reference to the Rhoptry-Microneme System*

SYNOPSIS The fine structure of the 3 generations of meronts, merogony, and merozoites of Eimeria labbeana Pinto from the ileal mucosa of experimentally infected pigeons, Columba livia Linnaeus, was described and compared to that of similar stages in other species of Eimeria. Sporozoite-trophozoite transition stages, trophozoites (5.8 × 4.2 μm), young meronts (10.1 × 8.4 μm), and mature meronts with free merozoites of the first generation, were observed at 20, 28, 36, and 48 hr post-infection, respectively. The 2nd and 3rd generation merogony were completed at 96 and 144 hr. Merogony was essentially of the ectomerogonous type without cytomere formation, as in most species. The average number of merozoites per meront in the 3 generations was 10 (5–15), 14 (8–19), and 7.5 (6–16); and the average size was 4.4 × 2.1 (4.1–5.9 × 1.8–2.2) μm, 4.2 × 1.8 (4.0–4.8 × 1.5–2.0) μm, and 5.4 × 1.8 (5.2–7.8 × 1.6–2.0) μm, respectively. Aggregation and subsequent degeneration of micronemes within membrane-bounded vesicles in the sporozoite-trophozoite stage, was observed as a possible mode of eliminating certain organelles present in the motile stages. Centrioles with (9 + 1) microtubular composition, and centrocones, were frequently seen in early meronts. Anlagen of micronemes, without any apparent association with the Golgi complex and the merozoite bud, were seen to develop in the cytoplasm of the meront. A single, median structure, probably representing the anlage of the rhoptry-microneme system was observed within the conoid of an early merozoite bud. Connections between the micronemes and the bulbous portion of the rhoptries, and a branched (interconnected ?) structure of the rhoptries observed in the present study, substantiate the present contention that the micronemes and rhoptries are functional forms of the same complex of organelles, the rhoptry-microneme system.     

Seven New Eimeria spp. (Protozoa,Coccidia) from Freshwater Fishes of Canada*

Seven new species of Eimeria are described and figured from the freshwater fishes of Ontario and Quebec, Canada. They are Eimeria catostomi sp. n. and E. fernandoae sp. n. from Catostomus commersoni (Lacépède), E. etheostomae sp. n. from Etheostoma exile (Girard), E. hoffmani sp. n. from Umbra limi (Kirtland), E. micropteri sp. n. from Micropterus dolomieui Lacépède E. pungitii sp. n. from Pungitius pungitius (Linnaeus), and E. salvelini sp. n. from Salvelinus fontinalis (Mitchill). Furthermore, 2 new host records and 2 new distribution records for North America are reported for E. anguillae Léger & Hollande, 1922 and E. truttae Léger & Hesse, 1919 respectively. Finally, morphologically similar oocysts found in various cyprinids are regarded as belonging to E. iroquoina Molnar & Fernando, 1974.     

Stages of Merogony in Multinucleate Merozoites of Eimeria magna Pérard, 1925*

SYNOPSIS. Stages of merogony of Eimeria magna were observed with the electron microscope in schizonts in ultrathin intestinal sections from white rabbits killed 4 days after inoculation. Some of the mature schizonts observed had uninucleate merozoites, whereas others had multinucleate ones. In each of the latter were rough endoplasmic reticulum, mitochondria, micronemes, refractile bodies, and occasionally, lipid droplets; some nuclei had a nucleolus. In the interior of some multinucleate merozoites, anlagen of daughter merozoites were observed. Each anlage was associated closely with a nucleus. In some of these nuclei, a cone-shaped pole of a spindle was directed toward the anlage. Each early anlage consisted of an inner membrane complex with a rhoptry anlage. A Golgi complex frequently was seen at the base of the anlage. One multinucleate merozoite, still attached to the residual body, had a merozoite anlage. In later stages of merogony, the anlagen were longer and each had a conoid. In one such merozoite, 2 merozoite anlagen were observed in close association with an eccentric intranuclear spindle, and 1 anlage had a Golgi adjunct. Another merozoite had an eccentric spindle and associated centrioles, but no visible anlagen. The finding of stages of merogony in multinucleate merozoites of E. magna indicates that these might represent a further schizogonic generation occurring in the original parasitophorous vacuole.     

Observations on the Life Cycle of Eimeria bilamellata Henry, 1932 in the Uinta Ground Squirrel Spermophilus armatus*

SYNOPSIS. Oocysts of Eimeria bilamellata were found in Spermophilus armatus, Utah and Wyoming; S. beecheyi, California; and S variegatus, Utah. Oocysts were not found in S. lateralis, S. richardsoni, S. columbianus, S. tridecemlineatus, or the white-tailed prairie dog, Cynomys leucurus. Experimental infections were established in S. armatus, S. variegatus, and S. lateralis, but not in S. richardsoni, least chipmunks Eutamius minimus, laboratory rats Rattus norvegicus, or Mongolian gerbils Meriones unguiculatus. After one experimental infection S. armatus and S. variegatus were immune to further infections. Spermophilus lateralis could be infected 3 or 4 times before the animals were immune. However, individuals of S. armatus in a natural population had more than one infection with E. bilamellata; probably infections must be of a certain level before immunity develops. When S. armatus were inoculated with about 100,000 oocysts, the animals usually died on the 7th day after incoculation. Oocysts were 33-37 by 25-31 μ (mean 34.5 by 28.2 μ). The oocyst wall was brown and composed of 2 layers. A distinct micropyle was present. Sporocysts were 18-23 by 9-12 μ (mean 19.9 by 10.3 μ). In experimental infections, the prepatent period was 10 days and the patent period 5–21 (mean 9) days. Schizonts were 1st seen 7 days after inoculation. They were located above the host cell nuclei of epithelial cells at the tips of the villi of the jejunum and ileum. One or more earlier generations of schizonts were thought to occur, but these were not observed. Gametogony took place in epithelial cells of the jejunum and ileum. Shortly after the merozoites entered the cells, the cells became enlarged and were displaced into the lamina propria. The microgametocytes were considerably larger than the macrogametes and contained a central residual body. Macrogametes had a peripheral eosinophilic layer as well as cytoplasmic granules; both apparently participated in formation of the oocyst wall.     

Fine Structure of the Endogenous Stages of Eimeria labbeana. I. The First Generation Merozoites

SYNOPSIS. The fine structure of the 1st generation merozoites of Eimeria labbeana from the ileal mucosa of artificially infected pigeons ( Columba livia ) was investigated and described. The 1st generation merozoites which appeared between 36-48 hr after infection averaged 4.4 × 2.1 μm in size. The 3-membraned pellicle was irregular in texture and harbored a single micropore, and many micropore-like invaginations. Closely apposed to the inner pellicular membrane were seen 22 microtubules, each 22–25 nm in diameter. An apical vesicle, 50 nm in diameter, seen at the anterior extremity, was connected with the common duct of the micronemes. The conoid consisted of 9 spiral elements, each 30 × 25 nm. The paired organelle (rhoptries) varied in length (1.4–2.2 μm), and the ductules (23 nm diameter) were composed of 2 inner tubules, each 6 nm in diameter. A unit membrane enveloped the partially alveolar and differentially osmiophilic interior of the bulbous regions of the rhoptries. The "rod-like structure"was found to be tubular and represented the common duct of the micronemes.     

The Effect of Eimeria nieschulzi Infection on Leukocyte Levels in the Rat*

SYNOPSIS. Rats inoculated with 10,000 sporulated oocysts of Eimeria nieschulzi had significantly higher total leukocyte counts on postinoculation days (PI) 1, 5, 6 and 7 when compared to control rats. Relative and absolute neutrophil counts increased concomitantly with a decrease in the relative lymphocyte levels in E. nieschulzi-infected rats on PI day 7. Absolute and relative neutrophil counts in infected rats on PI days 7 and 8 were closely correlated with the host's total oocyst discharge. The E. nieschulzi infection had no significant effect on the relative or absolute levels of monocytes or eosinophils. The described changes in leukocyte levels were not paralleled by a significant change in the erythrocyte count.     

Four New Species of Eimeria and One of Tyzzeria from the Ceylon Jungle Fowl Gallus lafayettei*

One species of Tyzzeria and 4 new species of Eimeria are described from the Ceylon jungle fowl Gallus lafayettei. The sporulated oocysts of Tyzzeria galli sp. n. are 13.8 (12–15) μ m; of Eimeria lafayettei sp. n., 19.5 (19–21) X 14.2 (13.5–15) μ m; of Eimeria indentata sp. n., 30.3 (29.5–32) X 21.4 (20–22) μ m; of Eimeria symmetrica sp. n., 35 × 28.5 μ m, and of Eimeria dissanaikei sp. n., 21 (19–23) X 14 (12–16) μ m. E. indentata, E. symmetrica, and E. dissanaikei produced patent infections in domestic fowl but T. galli and E. lafayettei did not. This is the 1st record of the genus Tyzzeria from the order Galliformes.     

Eimeria diminuta sp. n. from the Ceylon Jungle Fowl,Callus lafayettei*

SYNOPSIS. Eimeria diminuta sp. n. is described from the Ceylon jungle fowl Gallus lafayettei. Its sporulated oocysts are 16.5 (16–17.5) × 14.5 (13.5 × 15.5) μm. The species produces patent infections in domestic fowl.