The Endogenous Development of Eimeria alabamensis Christensen, 1941, an Intranuclear Coccidium of Cattle

SUMMARY. The endogenous development of the life cycle of Eimeria alabamensis Christensen, 1941, occurs in the nucleus of the intestinal cells of cattle. Calves were killed at various intervals after inoculation with infective oöcysts to study the endogenous cycle. Excysted sporozoites were found in the contents or scrapings from the walls of rumen, omasum, small intestine, cecum, and colon. They were found in the cytoplasm of intestinal epithelium at 2 days. Schizonts were found in the nuclei beginning at 2 days, but the number was low by the 8th day. Merozoite numbers usually ranged between 16 and 32. Some host nuclei contained as many as 48 or more, but these appeared to be the result of more than one schizont merging in the same host nucleus. Merozoites were slender, spindle-shaped bodies while still in the schizont walls, but were short with bluntly rounded tips when found in intracellular spaces and crypts. Gametocytes were found as early as the 4th day. Most of the stages of gametogenesis were limited to the lowest third of the small intestine, but in heavy infections some were also found in the cecum and upper colon. Microgametocytes were multinucleate and were more densely stained than the uninucleate macrogametocytes. The ratio of macrogametocytes to microgametocytes in 100 gametes was 78: 22. Oöcysis with "shells" were found in sections of the lower 20 feet of the ileum on the 6th day, which coincided with the shortest prepatent period reported previously. As many as three schizonts or microgametocytes or four or five macrogametocytes or oöcysts could be found in the same host nucleus. The variations in shape of the oöcysts appeared to be dependent on the number of oöcysts crowded into each nucleus.     

Effect of aging on antimicrobial immunity: old mice display a normal capacity for generating protective T cells and immunologic memory in response to infection with Listeria monocytogenes

Old (19 to 30 mo) and young adult (11 to 16 wk) AB6F1 mice of both sexes were compared in terms of their capacity to resist infection with Listeria monocytogenes. The LD50 was found to be two to four times higher for old than for young mice, and the time to death was longer for old mice. Enumeration of bacteria in the livers and spleens showed that old mice restricted growth of Listeria more effectively than young mice during the preimmune phase of infection, the difference being detectable as early as 12 to 24 hr after bacterial inoculation. Therefore, to ensure a similar level of infection in old and young mice, old mice had to be given a larger inoculum. Indeed, it was found that, provided the size of the bacterial inoculum was adjusted to make the level of immunizing infection the same, old mice generated similar levels of anti-Listeria immunity as young mice, as measured by their ability to generate splenic T cells capable of adoptively immunizing young recipients against lethal challenge infection. Furthermore, the level of memory immunity to reinfection 28 to 117 days after immunizing infection was similar in old and young mice. The results indicate, therefore, that old mice have no defect in their capacity to generate T cell-mediated anti-Listeria immunity.     

Attempted Passive Immunization of Young Calves Against Eimeria bovis

SYNOPSIS. Two experiments attempted to produce passive immunity against Eimeria bovis coccidiosis in Holstein-Friesian calves. Immune serum concentrated by a freezing technique, or serum globulin obtained by a precipitating technique from immune calves, was injected intravenously or intraperitoneally into young calves. Four calves received concentrated immune serum injected intravenously on the day of oral inoculation with sporulated oocysts and again 7 and 14 days later. Four calves were given intravenous injections with some of the same serum on the 7th and 14th days after inoculation and 4 others were given a single similar injection with the same serum 14 days after inoculation.
Three calves in a second experiment received intraperitoneal injections of serum globulins in increasing amounts every 3 days for 2 weeks. The calves were then orally inoculated with sporulated oocysts one week after the last globulin injection. Some calves receiving immune serum had an anaphylactoid reaction characterized by increased respiration rate, dyspnea, coughing, and salivation; however, all affected calves recovered spontaneously within 2 hours. Calves receiving serum globulin had no reactions.
Coccidiosis developed in all of the calves in spite of the injection of immune serum or globulin presumed to carry the immune factor. There was no detectable difference in the rate of oocyst discharge or in clinical symptoms between treated and control calves; therefore, no evidence of passive immunity was observed.     

Ostertagia ostertagi: establishment of patent infections in calves by intravenous inoculation

In two experiments calves raised free of parasite infection were given parenteral injections of Ostertagia ostertagi infective larvae to determine if patent infections might result. Patency was achieved by intravenous injection of larvae. Ten calves of different age (3–8 months) and sex were given intravenous, subcutaneous, and intraperitoneal injections of infective larvae. These calves were not necropsied; patency was based on fecal egg counts. Six calves injected intravenously all achieved patency (17–21 days after inoculation). Two calves each were inoculated subcutaneously and intraperitoneally; patency was observed in none. Calves given primary intravenous inoculation responded with higher levels of ova production to subsequent oral challenge inoculation.In a second experiment, six 2–3-month-old calves were injected intravenously with 186,000 infective larvae. Calves were killed at 2, 7, 12, 20 and 30 days after inoculation and had a tissue reaction in the lungs to migrating larvae characterized by focal granulomas, interstitial thickening of alveolar walls, and some hemorrhage. Infective larvae were recovered from the lungs at 2, 7 and 12 days, fourth stage larvae from the abomasum at 7 and 12 days, and adults only from the abomasum at 20 and 30 days. It was considered that larvae reached the abomasum by way of the trachea and by then being swallowed. Clinical signs of disease were not observed.     

Eimeria tenella: effects of immunity on sporozoites within the lumen of the small intestine

The effect of immunity on the numbers of sporozoites of Eimeria tenella recoverable from the lumen of the small intestine 1 hr after an oral challenge inoculum of oocysts was examined. The experiments were carried out in chickens which had been given an immunizing inoculum of oocysts 9 or 18 days earlier, and the results were compared with those obtained in a control, unprimed, but similarly challenged, group. Similar numbers of "challenge" sporozoites were found in the intestinal washes of control and 18 day primed chickens but there were fewer in the 9 day primed groups. The titers of antisporozoite IgA antibodies (measured by indirect fluorescence) were higher in the gall bladder bile of the 9 day primed groups but resistance to reinfection (measured by the output of oocysts in the feces after challenge with oocysts orally or with sporozoites intracecally) was greater in the 18 day primed group. Although fewer in number, the challenge sporozoites recovered from the intestinal washes of 9 day primed chickens appeared to be morphologically normal when examined by light microscopy. Also, they were as infective as sporozoites recovered from unprimed control, or 18 day primed, groups when injected intracecally into naive chickens. The findings indicate that, whereas reduction of the number of sporozoites of E. tenella in the lumen of the small intestine (presumably caused by the action of secreted antibodies) can be a means of reducing the effective challenge inoculum, this mechanism does not play a major role in the expression of immunity.     

Hymenolepis nana: Protective immunity against mouse-derived cysticercoids induced by initial inoculation with eggs

Mice were almost completely resistant to a mouse-derived cysticercoid (cyst) challenge after 6 to 10 months following an initial immunizing inoculation with eggs of Hymenolepis nana. Previously uninfected control mice of the same age became infected with the cyst-derived tapeworms. There was no age resistance to H. nana in mice. Immunity against the cyst challenge was acquired by initial egg inoculation and blocked by injecting cortisone acetate just prior to the challenge. However, the number of worms recovered from mice given cortisone was significantly less than that from nonimmunized controls. Unexpected evidence was obtained that a few of the egg-derived tapeworms can survive for 6 or more months in some of the immunized mice, which are resistant to both egg and cyst challenges. The relative immunogenicity of oncospheres and cysts is discussed. It is strongly suggested that the cysts are different from the oncospheres in their immunogenicity, and, because of this, H. nana can complete its life cycle in the same immunized host. It is also suggested that the host possesses at least two separate immune responses: One is an early response directed exclusively against the oncosphere and/or the early postoncospheral stage (s) acquired within 2 days of egg inoculation, and the other is a late response against the cyst acquired after a time lag of unknown duration.     

Primary infection with mouse-derived cysticercoids of Hymenolepis nana prepared from baby or adult mice and secondary infections with eggs or cysticercoids

Oral infection with mouse-derived cysticercoids (cysts) of Hymenolepis nana on day 0 did not make the 5 ± 1 week old mouse host immune to egg challenge by day 7 of the prepatent period, although the number of cyst-derived tapeworms was 1000 times greater than that of egg-derived tapeworms sufficient to make the host immune by day 7. Neither cysts recovered from immunologically competent 5 ± 1 week old donor mice, which should have become immune within 2 days of egg inoculation, nor those from incompetent 5–7 day-old baby mice given eggs when 0–2 days old made the host immune. The time course of differentiation of cysts in baby mice was not different from that in 5 ± 1 week-old mice. Mice infected twice with cysts on days 0 and 4 did not become immune either. Rapid protective immunity against egg challenge was acquired by inoculation exclusively with eggs but not with cysts. Apparently cysts differ from oncospheres in their immunogenicity. The importance of cysts for analysing the mouse—H. nana system from the immunological point of view is discussed.     

Hymenolepis nana: Maturation in an immunosuppressed unnatural rat host

When eggs of the dwarf tapeworm Hymenolepis nana, cycled exclusively and directly through mice for more than 10 years, were inoculated into previously uninfected inbred Fischer (F344) strain rats, they failed to mature in the rat intestinal lumen. Eggs of H. nana inoculated into the rat developed normally into cysticercoids (cysts) in the intestinal tissue, but thereafter failed to mature in the lumen except when the host was treated with cortisone acetate from the day of cyst maturation. The Fischer rat initially given eggs of H. nana became completely immune to egg challenge within 2 days of egg inoculation; no cysts derived from challenge eggs were found in the immunized rat. Immunosuppression, assessed by the success of cyst recovery in the tissue 4 days after egg challenge, had no promotive effect on the recovery of adult worms derived from eggs initially inoculated. Rats initially given eggs and immunosuppressed by cyclophosphamide or antithymocyte serum did not harbor any adult worms. Cortisone acetate treatment which was sufficient for eggs inoculated to mature (a total of 75 or even 200 mg, from Day 5 of egg inoculation) had no effects of immunosuppression, whereas cortisone acetate treatment which was sufficient for immunosuppression (a total of 150 mg from Day -2, two days prior to the initial egg inoculation) induced some adult formation as well. In addition, when mouse-derived cysts were inoculated into the rat instead of eggs, they also failed completely to mature even when the rat was treated with cyclophosphamide or antithimocyte serum. However, when the rat was treated with cortisone acetate from the day of cyst inoculation, the cysts developed into adult worms. Therefore, these results indicate that the Fischer rat clearly differs in its susceptibility to the tissue phase of egg inoculation and to the lumen phase of cyst inoculation of H. nana, and strongly suggest that the failure of maturation of H. nana in the unnatural host Fischer rat is not attributed to innate and/ or acquired immunity of the rat but to other nonimmunological mechanisms.     

GENERAL ACCOUNTS ON THE OÖCYTE GROWTH AND THE IDENTIFICATION OF VITELLOGENIN BY MEANS OF IMMUNOSPECIFICITY IN THE COCKROACH, BLATTELLA GERMANICA (L.)

The female Blattella germanica pushes out an oötheca 11 days after adult ecdysis and carries it for about 25 days until nymphs hatch out. The terminal oöcyte begins to accumulate yolk abruptly 4 or 5 days after adult ecdysis and grows fully on day 10 when its volume reaches 180 times as compared to that at adult ecdysis.
Vitellogenin, the vitellogenic female-specific protein, was identified by immunoelectrophoresis and Ouchterlony's test. Fluctuation of vitellogenin in the blood, ovary and embryo at various stages was analyzed. Vitellogenin appears in the female blood 3 or 4 days after adult ecdysis and disappears soon after terminal oöcytes have been released to an oötheca. In the ovary, it appears 4 or 5 days after adult ecdysis and disappears when terminal oöcytes leave the ovary. It remains in embryos until shortly before hatching, but is absent in newly hatched nymphs.     

Experimental induction of the two-host life cycle of Sarcocystis cruzi between dogs and Korean native calves

Eight dogs were experimentally infected with Sarcocystis by oral inoculation of cardiac muscle from naturally infected cattle. The infected dogs commenced discharging of sporocysts in the feces after 10 to 12 days of inoculation, and continued until 20 and 35 days after inoculation. Three dogs were reinfected with cardiac muscle from the naturally infected cattle. Sporocysts reappeared in the feces on 12 to 13 days after reinfection. Sarcocystis sporocysts collected from the experimentally infected dogs were fed to each of the two 30-day-old Korean native calves. The infected calves remained clinically normal, except for the high fever (> or = 40 degrees C) and decreased hematocrit values on day 30 to 40 post inoculation. Muscular cysts of Sarcocystis were found from infected calves on day 40 post inoculation. Proliferative forms of Sarcocystis were also observed in the muscle of infected calves. These results suggest that the Sarcocystis cruzi found in Korean native cattle has a 2-host life cycle with dogs as the definitive host and Korean native calves as the intermediate host.     

Evidence that anti-idiotype induced immunity to experimental African trypanosomiasis is genetically restricted and requires recognition of combining site-related idiotopes

The ability of anti-idiotypic (anti-Id) antibodies to immunize mice against African trypanosomiasis independent of antigen has been confirmed. Of three allogeneic anti-Id antibodies raised against three protective monoclonal antibodies, each with specificity for the variant surface antigen of a clone of Trypanosoma rhodesiense, only one (anti-7H11 Id) was effective in immunizing BALB/c mice against homologous challenge. The immunity was associated with the more rapid and enhanced expression of the corresponding Id after infection. The immunity was restricted to mice bearing genes linked to Igh-Ca, which appeared to control expression of this Id both in response to infection and anti-Id treatment. Another Id, 11D5, appeared to be under similar genetic control. Anti-11D5 Id, however, was ineffective in immunizing mice against infection despite inducing high levels of Id bearing molecules before challenge. The immunizing potential of the respective anti-Id antibodies appeared to be related to the relative concentrations of antibodies reactive with idiotopes near to or within the antigen-combining site, which, in turn, determined the relative proportion of Id-bearing clones activated that had antigen binding activity.     

Eimeria carolinensis n. sp., a Coccidium from the White-Footed Mouse, Peromyscus leucopus (Rafinesque)

SYNOPSIS. Eimeria carolinensis n.sp. (Sporozoa) is described from oöcysts in the feces of the white-footed mouse, Peromyscus leucopus (Rafinesque) taken in the vicinity of Durham, North Carolina. The oöcysts are ellipsoidal to elongate ellipsoidal, 14–19.5 × 10–13 μ, mean of 17.6 × 11.3 μ. Micropyle absent. Oöcyst wall composed of 2 layers. A refractile granule present but no oöcyst residuum. Sporocysts ovoid almost filling the oöcyst. Small Stieda body present.     

Sheep experimentally infected with sarcocystis from dogs. I. Disease in young lambs.

Eight Polled Dorset lambs were orally inoculated with Sarcocystis ovicanis sporocysts. Two lambs that received 100,000 or 200,000 sporocysts became clinically ill, recovered, and were killed 67 and 88 days after inoculation (DAI). Numerous intramuscular cysts were found in their skeletal and cardiac muscles. Three lambs received 100,000 sporocysts, three lambs received 1 million sporocysts, and three lambs received no sporocysts. After an acute clinical illness characterized by anemia, inappetence, weight loss, fever, and reduced serum protein, all lambs that received 100,000 sporocysts died 27 to 29 DAI and all that received 1 million sporocysts died 24 or 25 DAI. Hemorrhage involving the striated muscle and visceral organs was the most apparent gross lesion. The heart appeared most severely affected. Schizonts were found in vascular endothelial cells of all six inoculated lambs. Uninoculated lambs remained healthy, and neither lesions nor parasites were found in any tissues. Dogs fed tissues containing S. ovicanis cysts produced sporocytes 11 to 37 days after feeding; cats fed similar stages produced no sporocysts. Dogs fed tissues containing schizonts produced no sporocysts.     

Protection of calves against cryptosporiosis by oral inoculation with gamma-irradiated Cryptosporidium parvum oocysts

The purpose of this study was to determine whether gamma-irradiated Cryptosporidium parvum oocysts could elicit protective immunity against cryptosporidiosis in dairy calves. Cryptosporidium parvum Iowa strain oocysts (1 x 10(6) per inoculation) were exposed to various levels of gamma irradiation (350-500 Gy) and inoculated into 1-day-old dairy calves. The calves were examined daily for clinical signs of cryptosporidiosis, and fecal samples were processed for the presence of C. parvum oocysts. At 21 days of age, the calves were challenged by oral inoculation with 1 x 10(5) C. parvum oocysts and examined daily for oocyst shedding and clinical cryptosporidiosis. Calves that were inoculated with C. parvum oocysts exposed to 350-375 Gy shed C. parvum oocysts in feces. Higher irradiation doses (450 or 500 Gy) prevented oocyst development, but the calves remained susceptible to C. parvum challenge infection. Cryptosporidium parvum oocysts exposed to 400 Gy were incapable of any measurable development but retained the capacity to elicit a protective response against C. parvum challenge. These findings indicate that it may be possible to protect calves against cryptosporidiosis by inoculation with C. parvum oocysts exposed to 400-Gy gamma irradiation.     

Arrest, resorption, or maturation of oöcytes in Aedes aegypti: dependence on the quantity of blood and the interval between blood meals

ABSTRACT. After emergence, the follicles of A. aegypti double in length and the oöcytes may deposit a small amount of yolk, but within 2 days growth is arrested. Renewed growth and vitellogenesis, as well as the number of eggs finally produced, depends on the quantity of blood ingested. All females, given either a small (1 μl) or large (4 μl) meal of rat blood by enema, began yolk deposition in a nearly equal number of oöcytes, and each oöcyte had about the same amount of yolk 8 h later. Within 48 h, females fed 4 μl had each produced more than 100 eggs, whereas females fed 1 μl either had continued yolk deposition in some oöcytes, while most degenerated, or had all re-entered oögenic arrest. Consequently, 48 h after the 1 μl meal, a female had either c. 50 or 0 eggs. Even by 14 h after a 1-μl meal, females were either committed to re-enter oögenic arrest or to complete maturation of some oöcytes and resorb the yolk of others. This was shown by removing and examining one ovary 14 h after a blood meal and then giving a second blood meal. The second meal stimulated meal maturation in the remaining ovary, but only in those females whose oöcytes had been in oögenic arrest when the first ovary was examined; the second meal had no effect on females whose first ovary had contained both vitellogenic and degenerating oöcytes. Oösorption was not reversed by a second blood meal. Our results do not support the hypothesis that the female 'evaluates' the ingested meal and begins vitellogenesis in an 'appropriate' number of oöcytes. The results demonstrate that the ovary is an unreliable indicator of the frequency of blood-feeding, when females take a small meal.     

The response of sheep to parenteral vaccination and immunizing infections against the abomasal nematode, Haemonchus contortus

Adams D. B., Beh K. J. and Davies H. I. 1982. The response of sheep to parenteral vaccination and immunizing infections against the abomasal nematode, Haemonchus contortus. International Journal for Parasitology12: 445–449. Subcutaneous injection of relatively large amounts of unfractionated homogenates of adults plus infective larvae of Haemonchus contortus emulsified in complete Freund's adjuvant produced a degree of protective immunity when challenge infection was given eight weeks after the first or only dose of vaccine. In an attempt to improve acquired immunity, parenteral vaccination was either followed or preceded by a short immunizing infection with H. contortus, which was terminated by anthelmintic before patency. This treatment aimed at stimulating general responsiveness to worm antigens and invoking mucosal immunity in the abomasum. Disparate results were obtained; immunizing infections either increased immunity or made sheep more susceptible to challenge infection. In this latter situation, the unresponsiveness associated with primary infection with H. contortus may have been increased.     

Sporozoite-induced infections of the Salvador I strain of Plasmodium vivax in Saimiri sciureus boliviensis monkeys

Twenty Saimiri sciureus boliviensis monkeys from Bolivia were inoculated intravenously with sporozoites of the Salvador I strain of Plasmodium vivax. All animals were splenectomized 7 days after inoculation. Inoculation of 100,000 sporozoites resulted in prepatent periods averaging 16.6 days; all monkeys developed high-level parasitemias with an average maximum of 103,000 per mm3. Inoculation of 10,000 sporozoites resulted in average prepatent periods of 19.4 days; one of the resulting infections produced a transient low-level parasitemia. Of 5 monkeys inoculated with 1,000 sporozoites, 4 had prepatent periods of from 24 to 35 days and 1 failed to demonstrate any parasitemia; 1 monkey supported a low-level transient parasitemia, whereas the other 3 monkeys had high-level parasitemias. It is proposed that by using a minimum inoculum of 10,000 sporozoites, the model system may be useful in the testing of anti-sporozoite vaccines directed against P. vivax.     

Babesia bigemina: immune response of cattle inoculated with irradiated parasites

Effects of various radiation dosages on the infectivity and immunogenicity of Babesia bigemina were studied. Calves infected with 1 × 10¹⁰, B. bigemina parasitized erythrocytes exposed to 24 krad developed progressive parasitemias. Some calves receiving 1 × 10¹⁰ parasitized erythrocytes irradiated at 36 krad did not develop progressive infections. Progressive infections were prevented by exposure to irradiation at 48 and 60 krad. A degree of acquired resistance to infection with B. bigemina developed in calves after inoculation with parasites irradiated at 48 and 60 krad. The resistance developed was sufficient to suppress multiplication of the Babesia and to permit calves to survive otherwise severe clinical infections due to challenge with nonirradiated parasites. Irradiated parasites were frozen without apparent loss of immunizing properties.     

Immunization and immunosuppression in mice reared for high or low immune responsiveness against Nema tospiroides dubius

High (H) and low (L) immune responder mice (Sitepu & Dobson, 1982) were immunized with 5, 10, 20, 40 or 80 Nematospiroides dubius larvae, drenched 3 weeks later with anthelmintic then challenged with 100 larvae. Size of the inoculum of larvae correlated positively with the numbers of N. dubius eggs passed in the faeces of all these mice after the immunizing dose, and the size of the inoculum of immunizing larvae was negatively correlated with faecal epg, worm numbers and lengths of worms recovered from H but not L mice after challenge infection with 100 larvae. Increasing the number of N. dubius larvae in the immunizing inoculum enhanced the immunization of H mice, whereas the L mice were progressively immunosuppressed by increasing numbers of larvae.     

Immunisation of calves against bovine tropical theileriosis (Theileria annulata) with graded doses of sporozoites and irradiated sporozoites

Host responses to infections with serially diluted, unirradiated, infective Theileria annulata, tick tissue stabilates and irradiated stabilates, were compared and the resultant immunity tested against lethal homologous challenge. In infections due to unirradiated parasites duration of fever and proportion of schizontinfected cells in regional lymph nodes, and of parasitised erythrocytes in the peripheral circulation were directly related to the dose of the infective inoculum, whereas time responses, that is, times to first onset of fever and swelling of the regional lymph node, and to first appearance of parasites in the lymph node and blood were inversely related to the dose.Irradiation at 50 Gy did not appreciably affect the parasite. But in infections with the parasite irradiated at 100 Gy and 150 Gy, degrees of parasitisation were of reduced intensity and inversely proportional to the level of irradiation, whereas the time responses were unaffected except fever, onset of which was delayed. The minimal effect on time responses suggested that irradiation might have altered virulence rather than reduced the number of infective units in the inoculum.All the calves surviving the immunising infections fully resisted the challenge which produced severe theileriosis in unimmunised calves killing 3 of them. It was concluded, therefore, that both methods of immunisation conferred comparable levels of immunity on the animals.