Coccidiosis in wild grey kangaroos

Deaths occurred among wild grey kangaroos (Macropus giganteus) whose habitat was subject to flooding. A sample of the involved juvenile animals was hypoproteinaemic, and extensive haemorrhagic enteritis, associated with the presence of coccidial life cycle stages was found in the small intestine at necropsy. Masses of small schizonts infected cells of the lamina propria; large schizonts occupied clusters of hypertrophied cells; macrogametes and microgametocytes were observed in cells of the lamina propria. The species of coccidia involved could not be determined, although oocysts of Eimeria cunnamullensis and E. kogoni were found in faeces. Overcrowding, food shortage, damp conditions and possibly feed supplementation with hay on the ground were considered probable epizootiological factors contributing to an outbreak of coccidiosis among juvenile animals.     

Observations on the Endogenous Stages of Eimeria confusa Joseph, 1969 from the Grey Squirrel Sciurus carolinensis*

SYNOPSIS. Stages in the endogenous cycle of Eimeria confusa from the grey squirrel, Sciurus carolinensis, are described from mixed infections with another species, Eimeria lancasterensis. All corresponding stages were markedly different in the 2 species. In E. confusa infections, the parasites were located below the host cell nuclei of the epithelial cells of the villi of the jejunum and ileum. Mature schizonts were ellipsoidal, averaged 20.9 × 18.6 μm and had 18–30 merozoites. The mature microgamonts measured 34.3 × 24.7 μm and had hundreds of microgametes. Mature macrogametes were ovoid, averaged 31.3 × 25.6 μm, and contained 2 kinds of plastic granules.     

Comparative Development of Eimeria tenella from Sporozoites to Oocysts in Primary Kidney Cell Cultures from Gallinaceous Birds

Eimeria tenella completed its endogenous life cycle in primary cultures of kidney cells from 2- to 3-week-old-chickens, guinea fowl, partridges, pheasants, quail, and turkeys. Similarity in percentage of infection at 4 hr suggested that sporozoites entered cells from all birds in equal numbers. Development was better, however, in chicken cells in that the percentage of survival and of developmental stages during the first 2 days were greater, developmental stages occurring after 2 days usually were found earlier, mature 2nd-generation schizonts and oocysts were larger, and oocyst production was far greater than in nonhost cells. Multinucleate macrogametes, which sometimes reached sizes 3–4 times greater than normal oocysts, are reported for the first time.     

Endogenous stages of Eimeria sigmodontis (Protozoa: Eimeriidae) in the cotton rat, Sigmodon hispidus

Endogenous stages of Eimeria sigmodontis were studied in experimentally infected cotton rats, Sigmodon hispidus. The parasites were located in mucosal epithelial cells of the cecum and colon. E. sigmodontis had a typical coccidian endogenous cycle that consisted of three asexual schizogonous stages and sexual stages composed of the macrogametes and microgametes. The first-, second-, and third-generation schizonts contained 10–17, 5–8 and 10–21 merozoites, respectively. Only one type of wall-forming body was present in the macrogamete. The microgametocyte had a monocentric type of development.     

Endogenous stages of Eimeria tuskegeensis (Protozoa: Eimeriidae) in the cotton rat, Sigmodon hispidus

Endogenous stages of Eimeria tuskegeensis were studied in experimentally infected cotton rats, Sigmodon hispidus. Almost all parasites were located on the basilar side of the nucleus in epithelial cells on the sides and tips of villi of the small intestine. The endogenous cycle consisted of three generations of schizogony followed by gametogony. First-, second-, third-generation schizonts could be distinguished by time of appearance, size and shape of the schizont, and number, size, shape, and arrangement of merozoites. Immature gametogonous stages appeared to 84 hr postinoculation (PI) and developed into mature microgametocytes and macrogametes by 96 hr PI. Microgametocytes had a mono-centric type of development. Intermediate macrogametes had small, basophilic wall-forming bodies and mature macrogametes had large, eosinophilic wall-forming bodies. It was not possible to determine whether these were two distinct types of wall-forming bodies or whether they were different stages of a single type. Two nuclei were seen in the host's epithelial cells parasitized by schizonts, microgematocytes, macrogametes, and oocysts. This binucleate condition was apparently parasite-induced.     

Insight into the role of cetaceans in the life cycle of the tetraphyllideans (Platyhelminthes: Cestoda)

Four types of tetraphyllidean larvae infect cetaceans worldwide: two plerocercoids differing in size, ‘small’ (SP) and ‘large’ (LP), and two merocercoids referred to as Phyllobothrium delphini and Monorygma grimaldii. The latter merocercoid larvae parasitize marine mammals exclusively and exhibit a specialised cystic structure. Adult stages are unknown for any of the larvae and thus the role of cetaceans in the life cycle of these species has been a long-standing problem. The SP and LP forms are thought to be earlier stages of P. delphini and M. grimaldii that are presumed to infect large pelagic sharks that feed on cetaceans. A molecular analysis of the D2 variable region of the large subunit ribosomal DNA gene based on several individuals of each larval type collected from three Mediterranean species of cetaceans showed consistent and unique molecular signatures for each type regardless of host species or site of infection. The degree of divergence suggested that LP, P. delphini and M. grimaldii larvae may represent separate species, whereas SP may be conspecific with M. grimaldii. In all host species, individuals of SP accumulated in the gut areas in which the lymphoid tissue was especially developed. We suggest therefore that these larvae use the lymphatic system to migrate to the abdominal peritoneum and mesenteries where they develop into forms recognizable as M. grimaldii. The plerocercoid stage of P. delphini remains unknown. In a partial phylogenetic tree of the Tetraphyllidea, all larvae formed a clade that included a representative of the genus Clistobothrium, some species of which parasitize sharks such as the great white which is known to feed on cetaceans. A bibliographic examination of tetraphyllidean infections in marine mammals indicated that these larvae are acquired mostly offshore. In summary, the evidence suggests that cetaceans play a significant role in the life cycle of these larvae. In addition, it seems clear that cetaceans act as natural intermediate hosts for P. delphini and M. grimaldii, as within these hosts they undergo development from the plerocercoid stage to the merocercoid stage. Because tetraphyllidean species use fish, cephalopods and other marine invertebrates as intermediate hosts, the inclusion of cetaceans in the life cycle would have facilitated their transmission to apex predators such as the large, lamnid sharks. The biological significance of infections of LP in cetaceans is unclear, but infections do not seem to be accidental as such larvae show high prevalence and abundance as well as a high degree of site specificity, particularly in the anal crypts and bile ducts.     

Endogenous Cycle of the Swine Coccidium Eimeria debliecki Douwes, 1921*

SYNOPSIS. A pure strain of Eimeria debliecki (University of Illinois strain A) established from a single oocyst was used to determine the endogenous cycle. Young parasite-free pigs 2 weeks to 3 months old were used throughout the study. The endogenous cycle was found to take place in the small intestine where the parasites were located in the distal portion of the striated simple columnar epithelial cells of the villi. The first generation schizonts were found in only the jejunum (15% of small intestine). The second generation schizonts and gametes occurred in the jejunum and ileum (70% of small intestine), a slight posterior progression occurring with each stage. The entire cycle required 6.5 days. The schizogonous cycle comprised 2 generations. The first generation schizonts required 2.5 days to reach maturity, measured 8-12 μ, contained 16 merozoites measuring 12-15 μ and had a polar residual mass. The second generation schizonts required 2 days to reach maturity, measured 13-16 μ, contained 32 rotund merozoites measuring 6–8 μ, and had only a few granules of residual material. Gametogony took place in 1.5 days. The macrogametes measured 12-16 μ, and the microgametocytes measured 9-14 μ with microgametes measuring 5–6 μ.     

Intralymphocytic schizonts associated with an initial infection of Saurocytozoon tupinambi in Tupinambis teguixin

An initial natural infection of Saurocytozoon tupinambi in a juvenile Tupinambis teguixin from Venezuela was studied for 131 days following capture of the host. Intralymphocytic parasites appeared in this sequence: small uninucleate and binucleate stages (days 1–31 and again on day 41); schizonts with 3–102 nuclei (days 8–14 and 29–35); immature gametocytes (days 29–35) and apparently mature gametocytes of Saurocytozoon tupinambi from day 41. Maximum parasitemia of trophozoites and binucleate schizonts occurred on day 4 when 11% of lymphocytes were infected. Maximum parasitemia by larger schizonts occurred on day 8 at 0.13% of lymphocytes, while maximum gametocytemia was found on day 49 with 16.4% of lymphocytes parasitized. Two types of schizonts were observed: intralymphocytic and the same type free of host cells, and fragments of varying size which may have been torn from capillary endothelium.Due to presence of concurrent infection by a small Plasmodium species, identity of intralymphocytic asexual stages with S. tupinambi cannot be established. Presence of asexual and sexual stages in the same type of host cells (lymphocytes and close derivatives), sequential appearance of trophozoites, schizonts and gametocytes over a period of 40 days, and correlated fluctuations in lymphocyte density suggest they are conspecific, and that Saurocytozoon, which has a plasmodiid type of sporogony may prove to further differ from leucocytozoids by presence of an asexual cycle in circulating blood cells.     

The Morphology and Behavior of Living Exoerythrocytic Stages of Plasmodium gallinaceum and P. fallax and Their Host Cells

The morphology and behavior of living exoerythrocytic stages of Plasmodium gallinaceum and P. fallax were studied by the use of tissue cultures, phase contrast microscopy, and time-lapse cinephotomicrography. The morphology of exoerythrocytic stages of these two species was essentially that previously observed in fixed, stained material, with the following exceptions: (1) the presence of a filament on one end of the merozoite, (2) the absence of clefts in the cytoplasm of the large schizonts, and (3) the absence of a vacuole-like space around the parasite. The following behavior was observed either directly or in time-lapse sequences: (1) emergence of merozoites from mature schizonts, (2) progressive motility of free merozoites, (3) entry of merozoites, both actively and passively, into host cells, (4) nuclear division in the parasite, (5) the various stages of schizogony, including final production of merozoites, (6) massive infection of host cells, and (7) phagocytosis of merozoites and attempted phagocytosis of mature schizonts by macrophages. Exoerythrocytic stages of P. fallax differed from those of P. gallinaceum in that the merozoites of the former were (1) somewhat more curved in shape and (2) present in fewer numbers in mature schizonts. The use of tissue culture, phase contrast microscopy, and time-lapse cinephotomicrography promises to solve many of the remaining problems concerning exoerythrocytic stages of malarial parasites and their interrelationships with host cells.     

The Life Cycle of Isospora felis Wenyon, 1923, a Coccidium of the Cat*

SYNOPSIS. A pure strain of Isospora felis derived from a single oocyst was used to study the endogenous cycle. One and a half to two-month-old laboratory-reared, coccidia-free kittens were used thruout the study. The endogenous stages occurred in the epithelial cells of the distal parts of the villi in the ileum and occasionally duodenum and jejunum. All stages lay above the host cell nucleus. There were 3 asexual generations. The 1st generation schizonts were 11–30 by 10–23 μ when mature and contained 16–17 banana-shaped merozoites 11–15 by 3–5 μ. They became mature in 96 or sometimes in 120 hours. The 1st generation merozoites entered new host cells, rounded up and formed 2nd generation schizonts. These formed within themselves 2–10 or more spindle-shaped bodies resembling 1st generation merozoites in shape and size. These were 2nd generation merozoites. They were uninucleate 120 hours after inoculation, but by 144 hours they became larger, multinucleate and some lost their elongate shape and became ovoid. They were then 3rd generation schizonts. They were 12–16 by 4–5 μ. Each formed up to 6 or more banana-shaped merozoites 6–8 by 1–2 μ. The 3rd generation schizonts and merozoites developed within the same host cell and parasitophorous vacuole as the 2nd generation schizonts and merozoites. Mature schizonts containing only 3rd generation merozoites appeared 144 hours after inoculation, were most abundant 168 hours after inoculation, and might be present as late as 216 hours after inoculation. They were 14–36 by 13–22 μ and contained 36 to more than 70 merozoites. The 3rd generation merozoites entered the sexual cycle. The mature microgametocytes were 24–72 by 18–32 μ and contained a central residuum and a large number of microgametes 5–7 by 0.8 μ with 2 posteriorly-directed flagella. The mature macrogametes were 16–22 by 8–13 μ. Gametogony occurred 144–216 hours after inoculation. The prepatent period was 168–192 hours and the patent period 10–11 days. Peak oocyst production occurred on the 6th day of the patent period.     

Discovery of the pre-erythrocytic stages of a saurian malaria parasite, hypnozoites, and a possible mechanism for the maintenance of chronic infections throughout the life of the host

Re-examination of tissue sections from four Takydromus tachydromoides (Sauria: Lacertidae) naturally infected with Plasmodium sasai found liver parenchymal cells, containing uninucleate parasites which may correspond to the hypnozoite stage of primate malaria parasites, schizonts and segmenters in parenchymal cells, and hepatic macrophages which contained numerous schizonts. Following destaining of the original H&E and prolonged restaining with warm Giemsa stain, encysted schizonts, protected by a hyaline wall, were discovered in the connective tissue or capillary endothelium of lung, liver, brain, heart, pancreas, kidney, intestine wall, testis, and both intra- and intermuscularly in the femoral muscles. Unencysted schizonts in the pulmonary endothelium apparently represent the phanerozoic stages, which, following encystment in the various tissues, are recognized as a new stage in the life cycle of reptilian malarial parasites, the chronozoic schizonts. A hypothesis is presented to describe the life cycle of P. sasai, which may be characteristic of other saurian malaria parasites. It interprets the sequence of pre-erythrocytic stages found as follows: sporozoites enter hepatic parenchymal cells where some may become dormant as hypnozoites, and others form cryptozoic schizonts. The cryptozoites parasitize hepatic macrophages and form metacryptozoic schizonts. Metacryptozoites produce phanerozoic schizonts in the capillary endothelium and connective tissue of the lung and other organs. Phanerozoites and possibly metacryptozoites then invade the erythrocytes to begin the erythrocytic cycle. Some of the phanerozoites in endothelium, connective tissue and skeletal muscle become encysted as chronozoic schizonts, and their progeny, chronozoites, renew the erythrocytic cycle throughout the life of the host and produce seasonal relapses of gametocytemia, in spring, at the end of hibernation by the lizard.     

Isospora lacazei (Labbe, 1893) and I. chloridis sp. n. (Protozoa: Eimeriidae) from the English Sparrow (Passer domesticus), Greenfinch (Chloris chloris) and Chaffinch (Fringilla coelebs)

SYNOPSIS. Two species of Isospora are described from Chloris chloris with the additional hosts Passer domesticus and Fringilla coelebs. I. lacazei Labbé has spherical oocysts measuring 16.6 to 30.0 μ; the oocyst wall is colorless and smooth, consisting of a thick layer and, in the majority of oocysts, an inner thin membrane. Stages of the life cycle in the epithelial cells of the duodenum are described. The internal stages consist of first and late generation schizonts which produce merozoites without any residual body, spindle-shaped microgametes and macrogametes without obvious "plastic granules." The oocysts of I. chloridis sp. n. have colorless, smooth surfaced walls of one thick layer. They are ellipsoidal, measuring 17.2-33.2 μ× 16.6-30.0 μ. The internal stages of this species infect the epithelial cells of the small intestine in the same region as I. lacazei. They produce 2 generations of schizonts, consisting of merozoites and a residuum; microgametes are comma-shaped and macrogametes have obvious "plastic granules."     

毁灭泰泽球虫Tyzzeria Perniciosa(Sporozoa:Eimeriidae)生活史各阶段的细胞化学研究:Ⅰ.多糖

本实验分别用过碘酸——雪夫氏剂染色方法(PAS)和乌洛托品——硝酸银染色方法在光镜和电镜下检验毁灭泰泽球虫生活史各时期体内的多糖及其分布。实验结果表明,子孢子内、各代裂殖体和裂殖子内都含有多糖。大配子和合子内除含有多糖外还含有成囊颗粒。成囊颗粒的成分是糖蛋白。无性世代的滋养体和多核体内未检出多糖。早期配子细胞,小配子体和小配子内也未检出多糖。本实验证明,毁灭泰泽球虫体内的多糖系由其自身合成,并在其发育过程中消耗。     

Redescription and Life History of Contortylenchus brevicomi,a Parasite of the Southern Pine Beetle Dendroctonus frontalis

Larval and adult life stages are described for Contortylenchus brevicomi (Massey) Rühm parasitizing a Mississippi population of Dendroctonus frontalis, the southern pine beetle. Fourth-stage larvae and free-living adult females of this species are identified and described for the first time. The life cycle of C. brevicomi can be reconstructed from this study. The adult female nematode lays eggs in a mature beetle. Larval development progresses within the hemocoel until fourth-stage larvae exit the host. Mating occurs in beetle galleries and only females enter an immature beetle host.     

Pathobiology of Borrelia theileri in the tropical cattle tick, Boophilus microplus

The development of Borrelia theileri infections in the tick Boophilus microplus was studied during all stages of the tick developmental cycle. Light microscopical examination of hemolymph and ovary smears from ovipositing females allowed identification and separation of infected and uninfected ticks. A Borreli-free tick colony was established. Small numbers of spirochetes were present in larvae, with numbers increasing through the nymphal and adult tick stages. Borreliae occurred in hemolymph, hypodermis, midgut, Malpighian tubules, ovary, Gené's organ, and the central ganglion of engorging and ovipositing females and their eggs. The ovary, central ganglion, and hemolymph seemed to be preferred sites for the spirochete, with extensive multiplication occurring in hemocytes. No measurable effect of spirochete multiplication upon feeding and reproductive performance of ticks could be detected. Infections in cattle caused fever of short duration which coincided with the presence of spirochetes in blood smears. Morphology and size of blood and tick forms were consistent with those of B. theileri reported by other authors. B. theileri is important because infections of invertebrate and vertebrate hosts may interfere with the interpretation of data in various experimental designs, and because it is probably endemic in populations of one or more tick species and their hosts throughout the world.     

The fine structure of the endogenous stages of Eimeria labbeana. 3. Feeding Organelles.

The fine structure of the feeding organelles of the endogenous developmental stages of Eimeria labbeana from the ileal mucosa of the common Pigeon, Columba livia, is described and compared with similar structures of other species of Eimeria. Intra-cytoplasmic, membrane-bound vesicles of varying shapes and dimensions, and pinocytotic vesicle, were seen in association with cup-shaped or v-shaped invaginations in early schizonts, early macrogamonts, and macrogametes. Deep invaginations, averaging 1.7 x 0.5 mu in size, and found on the surface of early schizonts, early and young macrogamonts, and developing microgamonts, apparently function as organelles of ingestion and breakdown of host-cell cytoplasm. Micropores were rarely seen in schizonts and never in microgametes. The merozoite had one typical micropore (850 x 680 A) and a number of micropore-like invaginations. Micropores of the microgamonts averaged 610 x 580A, and those of macrogamonts and macrogametes averaged 1,220 x 780 A. A typical micropore was observed in an early oocyst. Intravacuolar tubules, each 580 A in diameter and composed of nine microtubule-like subunits, were observed only in about 1 per cent of the more than 4,000 macrogametes studied. This paper establishes that E. labbeana is a species that possesses all the known organelles associated with feeding, expect the intravacuolar folds.     

The malarial parasites of Anolis species (Sauria: Iguanidae) in Panama

Lizards of the iguanid genus Anolis in Panama are parasitized by four species of Plasmodium. P.floridense occurs in A. limifrons, A. biporcatus, A. pentaprion and A. frenatus. The number of nuclei in mature schizonts is influenced by host species as is gametocyte shape but not gametocyte size. P. tropiduri parasitizes A. limifrons, A. pentaprion, A. biporcatus, A. frenatus, A. lionotus and A. poecilopus. The number of nuclei in schizonts varies according to host and type of blood cell parasitized. Gametocyte size varies slightly by host but shape remains relatively constant. Position of the parasite in the host cell may be affected by host species. Both schizonts and gametocytes are produced in white cells of all host species studied. P. balli occurs in A. limifrons, A. lionotus and A. poecilopus. Schizont and gametocyte size and shape are affected by host and blood cell type, with the parasite exhibiting different preferences for various blood cells in each host. P. minasense parasitizes A. limifrons, A. frenatus and A. capito, but its diagnosis in the last species may not be correct as gametocyte size and distribution of pigment differ considerably from other hosts. The mean number of nuclei in schizonts is not greatly affected by the host species. P. floridense is postulated to be of middle American origin in the genus Anolis, and to have reached Florida through the Caribbean.     

The Life Cycle of Eimeria vermiformis Ernst,Chobotar and Hammond, 1971 in the Mouse Mus musculus1

SYNOPSIS. The life cycle of Eimeria vermiformis from the mouse Mus musculus is described from experimental infections. The prepatent period was 7 days, and the patent period 7–22+ days. Endogenous stages were in the lower 2/3 of the small intestine. Two generations of schizonts were found. Mature 1st generation schizonts, seen 4 days after inoculation, were 16–25 × 9–16 μ and had long vermiform merozoites. Mature 2nd generation schizonts were first seen 5 days after inoculation. They were 8–18 × 7–14 μ (mean 11.2 × 13.1 μ). Mature microgametocytes, 17–32 × 12–25 μ, were present 6 days after inoculation. Macrogametes with plastic granules were found at the same time. The life cycle of E. vermiformis is compared with those of other species of Eimeria from Mus.     

Ultrastructural studies on the fungus,Nomuraea rileyi,infecting the velvetbean caterpillar,Anticarsia gemmatalis

Combined scanning and transmission electron microscopy was used to study the fine structure of the developmental stages of Nomuraea rileyi infecting host larvae of Anticarsia gemmatalis. Larvae were dusted with large numbers of fungal conidia, which germinated and penetrated the cuticle within 6 hr post-treatment. Within 24 hr, penetration hyphae had reached the cuticular epidermis and, via a budding process, initiated the hyphal body stage in the hemocoel. The hyphal bodies, suspended in hemolymph, multiplied and spread throughout the host larvae. By 6–7 days post-treatment, the majority of larvae were mummified. Within 12 hr postmortem numerous conidiophores emerged producing a confluent mycelial mat over the entire cuticular surface. Numerous hydrophobic conidia were formed on phialides present on the aerial conidiophores.