Systematics of the Eimerian Parasites from North American Snakes of the Family Colubridae,and their Prevalence in the Colubrids of Iowa*

A survey of 117 Iowa snakes, representing 18 species within 12 genera, revealed the presence of 6 species of Eimeria, 5 of which are described as new and 1 of which (E. zamenis) is redescribed. Those species found, the average length-width dimensions of their oocysts ( in micrometers ), and the respective hosts from which they were isolated were as follows: E. attenuata sp. n., 22.2 × 12.6, from 1 of 25 red-sided garter snakes [Thamnophis sirtalis parietalis (Say)] and 1 of 14 northern water snakes [Natrix sipedon sipedon (Linnaeus)]; E. iowaensis sp. n., 17.8 × 14.5, from 1 of 25 redsided garter snakes; E. hydrophis sp. n., 15.4 × 10.9, from 5 of 14 northern water snakes and 1 of 1 diamond-backed water snake [N. rhombifera rhombifera (Hallowell)]; E. helmisophis sp. n., 13.8 × 10.6, from 1 of 5 western worm snakes [Carphophis amoenus vermis (Kennicott)]; E. collanuli sp. n., 33.1 × 18.3, from 1 of 14 prairie ring-neck snakes (Diadophis punctatus arnyi Kennicott), and E. zamenis, 31.0 × 17.0, from 1 of 6 eastern yellow-bellied racers (Coluber constrictor flaviventris Say) and 1 of 1 eastern milk snake [Lampropeltis triangulum triangulum (Lacépède)]. The overall infection rate for the 117 snakes examined was 9.2%; these data are tabulated. In addition, the possible synonymy of E. lampropeltis with E. zamenis is considered, and the probable status of E. attenuata, E. hydrophis, E. zamenis, and E. annea, as parasites of multiple host species, is reviewed with regard to the phylogenetic relationships of the respective hosts from which they have been reported.     

Eimeria acervulina and E. tenella:effect on methionine absorption by the avian intestine.

Absorption of l-methionine in the duodenum of intestine of chicks infected with Eimeria acervulina was markedly less than in uninoculated controls or birds infected with E. tenella. Absorption of methionine in the jejunal area of E. acervulina-infected birds was reduced although not as drastically as in the duodenum. There was no difference in the rate of methionine absorption by the ileum. The kinetics of methionine absorption showed that V_max (maximum velocity) in the duodenum and jejunum of E. acervulina-infected birds was reduced when compared with the V_max found in uninoculated controls or E. tenella-infected birds. There was no difference in the K_t (transport constant) regardless of the infection or the region of the intestine examined. No major consistent effect of decreased pH on the rate of methionine absorption could be shown.The broadly spatulate villi seen, using the scanning electron microscope, in control and E. tenella infected duodenum were absent in E. acervulina-infected duodenum. Instead, the villi were reduced in height and noticeably thickened. This reduction in villar height suggests that a portion of the reduction in methionine absorption was related to the change in surface area and loss of transport loci due to damage of the mucosal surface.     

Monoclonal Antibodies Identify a Subset of Dense Granules in Cryptosporidium parvum Zoites and Gamonts

ABSTRACT. Two monoclonal antibodies raised against purified oocysts and excysted sporozoites of Cryptosporidium parvum identified antigens located in the anterior half of sporozoites by indirect immunofluorescence microscopic assay. The monoclonal antibodies also reacted with Triton X-100-insoluble antigens of asexual and sexual stage parasites developing in epithelial cells in vitro and identified a 110 kilodalton antigen on immunoblots of sodium dodecyl sulfate-extracted oocysts. Immunoblotting reactivity was abolished by prior treatment of blotted antigen with periodic acid suggesting that the monoclonal antibodies recognize a carbohydrate or carbohydrate-dependent epitope(s). By immunoelectron microscopy, the antibodies reacted with a family of small, electron-dense granules located predominantly in the central region of merozoites and also with a population of cytoplasmic inclusions in macrogamonts. In addition, the monoclonal antibodies prominently labeled the parasitophorous vacuole membrane of all intracellular stages examined suggesting that the corresponding antigen(s) may be exocytosed from the granules to become associated with Triton X-100-insoluble components of the vacuolar membrane or cytoskeleton.     

捕食风险对越冬根田鼠肠道寄生物易感性的影响

在自然生态系统中,不同营养级物种可通过特征介导间接效应对生态系统的稳定及种群产生深刻的影响。但目前有关特征介导间接效应的实验研究多见于无脊椎动物、鱼类和两爬类。本研究以根田鼠为对象,在野外围栏内建立预防捕食者和未预防捕食者两种实验处理种群,并通过采用麦克马斯特法测定两种处理种群实验个体肠道寄生物感染种类及感染率和感染强度,采用PHA（phytohemagglutinin）反应和白细胞分类计数测定不同处理种群实验个体免疫能力,以分析捕食风险对根田鼠肠道寄生物的感染效应。结果表明,未预防捕食者处理组根田鼠PHA反应、白细胞计数和淋巴细胞计数较预防捕食者处理组实验个体显著降低,而球虫 E. wenrichi 的感染率和感染强度则显著增加,但绦虫和线虫以及其他3种球虫的感染率和感染强度无显著差异。结果表明,捕食者可通过介导猎物免疫力特征而间接影响猎物肠道寄生物的感染,验证了本项提出的捕食风险可通过降低根田鼠的免疫能力而增加其肠道寄生物感染的假设。     

Toxoplasma gondii: growth in ovine fetal kidney cell cultures

Serial, in vitro passage of Toxoplasma gondii (Rh strain) was successfully performed in a cell line derived from ovine fetal kidney cells. Invasion of this parasite into the kidney cells was easily discernible 1 hr after inoculation. The subsequent proliferation of the parasite was followed in the cytoplasm of the kidney cells. Very active endodyogeny and rosette formations, as many as 13 in a cell, were observed in the cytoplasm of the kidney cells 48 hr postinoculation. After 96 hr of incubation, the parasite population had increased about 132-fold. The virulence of T. gondii against mice was not attenuated after 2 years of in vitro growth which represented 100 serial passages through the kidney cell cultures. Although no "exotoxin" was produced by T. gondii grown in vitro, a Toxoplasma sp. agar gel immunodiffusion test antigen was isolated from the cell-free supernatant fluid of the kidney cell cultures which was identical to an antigen isolated from "toxogenic" organisms harvested from infected mice.     

Some Problems of Host and Parasite Interactions in the Coccidia*

SYNOPSIS. The current status of some concepts of host and parasite interactions in the coccidia are discussed and evaluated. It is suggested that winter coccidiosis of cattle caused by Eimeria zuernii results from activation of arrested endogenous stages in the tissues of the host. A second aspect of clinical coccidiosis is that infections are seldom monospecific, but little work has been done on infections in animals with multiple species of coccidia. Information in the literature indicates that there are interactions between species of Eimeria in concurrent infections, and it is hoped that investigators will undertake studies to define more clearly what interactions there may be. Finally, the finding that there is a genetic basis for successful transmission of Eimeria separata from rats to mice provides a tool for studying the basis of host-specificity in the coccidia.     

Eimeria meleagrimitis, E. adenoeides, and E. dispersa: Severity of infection and changes in the intestinal mucosa of the Turkey

Glucose and methionine were malabsorbed in some intestinal regions of turkeys infected with Eimeria meleagrimitis, E. adenoeides, or E. dispersa. The decrease in absorption was not always related to the numbers of parasites in the cells or the extent of damage to the mucosa. With E. adenoeides, malabsorption was found in the jejunum even though parasites were not present. Conversely, with E. dispersa, no malabsorption was observed in the duodenum even though light microscopy showed numerous parasites. In many intestinal regions, damage to the mucosal surface visible with scanning electron microscopy (SEM) was slight or absent, although malabsorption was marked. No changes were noted with SEM in the structure and orientation of the brush border in these regions. Villar height was significantly reduced in the regions of heaviest infection when intestinal damage was visible. Conversely, the crypts of Lieberkühn were often two or three times as deep in infected poults as in uninfected poults. In general, no differences were found in the thickness of the circular and longitudinal muscle layers between the infected and uninfected poults. The dry weight of the intestinal tissue was less from infected poults than from uninoculated controls and was related to both region of the intestine and severity of the infection.     

Eimeria Spp.: Influence of coccidia on digestion (amylolytic activity) in broiler chickens

Loss in pancreatic weight and an overall decrease in amylolytic activity in the pancreas were seen in broiler chickens infected with Eimeria acervulina, E. maxima, and E. necatrix. Only E. acervulina and E. maxima reduced amylolytic activity in the surface mucosa of the regions they infected. Surface-bound amylolytic activity decreased as the severity of infection (as measured by lesion score) with E. acervulina increased. This decrease in activity was not related to the decreased feed consumption in infected birds. Little decrease in amylase activity was found in the lumenal contents with the exception of E. acervulina in the jejunum. When the effect of pH on enzyme activity was studied in vitro, a marked reduction in amylolytic activity was observed as the pH went below 5.0.     

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。     

The development of the macrogamete and oocyst wall in Eimeria maxima: immuno-light and electron microscopy

We have identified, and followed the development of three macrogamete organelles involved in the formation of the oocyst wall of Eimeria maxima. The first were small lucent vacuoles that cross-reacted with antibodies to the apple domains of the Toxoplasma gondii microneme protein 4. They appeared early in development and were secreted during macrogamete maturation to form an outer veil and were termed veil forming bodies. The second were the wall forming bodies type 1, large, electron dense vacuoles that stained positively only with antibodies raised to an enriched preparation of the native forms of 56 (gam56), 82 (gam82) and 230 kDa (gam230) gametocyte antigens (termed anti-APGA). The third were the wall forming bodies type 2, which appeared before the wall forming bodies type 1 but remain enclosed within the rough endoplasmic reticulum and stained positively with antibodies raised to recombinant versions of gam56 (anti-gam56), gam82 (anti-gam82) and gam230 (anti-gam230) plus anti-APGA. At the initiation of oocyst wall formation, the anti-T. gondii microneme protein 4 positive outer veil detached from the surface. The outer layer of the oocyst wall was formed by the release of the contents of wall forming bodies type 1 at the surface to form an electron dense, anti-APGA positive layer. The wall forming bodies type 2 appeared, subsequently, to give rise to the electron lucent inner layer. Thus, oocyst wall formation in E. maxima represents a sequential release of the contents of the veil forming bodies, wall forming bodies types 1 and 2 and this may be controlled at the level of the rough endoplasmic reticulum/Golgi body.