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Morphological variation of Moniliformis moniliformis (Bremser 1811) Travassos 1915 and Moniliformis clarki (Ward 1917) Chandler 1921.

A two-way fixed model analysis of variance was used to test Moniliformis moniliformis and M. clarki for inter- and intraspecific differences with respect to 7 morphological characters used to distinguish species of the genus. M. clarki was sexually dimorphic in more characters than was M. moniliformis when specimens from their usual definitive hosts, Spermophilus tridecemlineatus and Rattus norvegicus, respectively, were compared. More characters were sexually dimorphic in both species reared in hamsters, Mesocricetus auratus, than in their usual definitive hosts or M. clarki from rats. Moniliformis clarki and M. moniliformis (n = 25 each sex, each species) from their usual hosts were significantly different at the 1% level in 6 of 7 characters studied. Further M. clarki of either sex from ground squirrels did not differ significantly in any of the 7 characters from those of the same sex from rats. When reared in hamsters, the range in number of longitudinal rows of proboscis hooks of female M. moniliformis included that of M. clarki, but the 2 species were distinct in each of the other features which distinguished them in rats and ground squirrels.

Acanthocephala↗

Worm kinetics and serum IgE in hooded lister rats infected with the acanthocephalan Moniliformis moniliformis and the nematode Nippostrongylus brasiliensis.

After infection with the intestinal helminths Moniliformis moniliformis or Nippostrongylus brasiliensis, worm-specific IgE first appeared in the serum rats between days 10 and 24 p.i., varying with host age, worm species and worm dose used. The rate of increase in specific IgE was comparable regardless of the worm species, infection dose or host age and a peak response was observed about 1 month after the sera turned positive. In the M. moniliformis infections, these events took place long before the beginning of worm expulsion on day 63 in high-dose (50 worms) infections, and potentiation of heterologous IgE was not observed. In contrast, IgE stimulation by N. brasiliensis infections was detected as potentiation of anti-ovalbumin IgE, anti-M. moniliformis IgE and total IgE. Most of the total IgE in the serum of M. moniliformis-infected rats was likely to be the worm-specific IgE. Anthelminthic removal of M. moniliformis revealed that the presence of residual worms was necessary to maintain worm-specific IgE production.

Aging↗

Accumulation and distribution of lead in the archiacanthocephalan Moniliformis moniliformis from experimentally infected rats.

It recently became clear that adult eo- and palaeacanthocephalans parasitizing fish can bioconcentrate several heavy metals to significantly higher concentrations than the tissues of their definitive hosts. Following this discovery the lead accumulation of the archiacanthocephalan Moniliformis moniliformis was investigated using experimentally infected male Wistar rats of the CD-M-strain. The worms were allowed to grow up for 4 weeks post-infection followed by a 3 weeks oral lead exposure of the rats. After the exposure period the rats were killed and the metal levels were determined in muscle, liver, intestine and kidney of the rats as well as in different organs of female and male acanthocephalans. Lead concentrations were found to be highest in female M. moniliformis followed by the kidneys of the rats. Male worms contained approximately the same lead concentration as the hosts' kidneys. Lead analysis of the worms' organs revealed the highest lead concentration in the eggs of female acanthocephalans, followed by the cement gland of male Worms. Whilst the lead burden of the presoma was higher than that detected in the kidneys of the rats, the lead content of the metasoma was even lower than in the kidneys. A lead uptake of M. moniliformis from the intestinal lumen of the host became apparent as the faeces of infected rats contained significantly less lead compared to the uninfected conspecifics. Thus, this study reveals that lead accumulation also occurs in archiacanthocephalans parasitizing mammals. But the degree of metal bioconcentration is considerably lower compared to eo- and palaeacanthocephalans in fish. Anyway, due to a lack of adequate sentinel species in terrestrial biotopes the host-parasite system rat M. moniliformis appears to be a useful and promising bioindication system especially in urban ecosystems in temperate regions.

Animals↗

Cadmium accumulation in Moniliformis moniliformis (Acanthocephala) from experimentally infected rats.

The accumulation of cadmium in Moniliformis moniliformis parasitizing experimentally infected rats that had been orally exposed to cadmium was investigated in this study. Cadmium accumulation in the helminth and in different tissues of the host was determined using electrothermal atomic absorption spectrometry (AAS) after a 3-week period of exposure. The mean cadmium concentration measured in M. moniliformis was 5.8 microg g(-1) wet weight, which was 20, 23, and 119 times higher than that determined in the kidney, liver, and intestine of the host, respectively. Although female worms accumulated higher amounts of cadmium than did males, no tendency emerged between the cadmium concentration and the weight of individual acanthocephalans. This study reveals that cadmium accumulation also occurs in archiacanthocephalans, but to a lesser degree than in palaeacanthocephalans parasitizing fish. Due to its cadmium-accumulation capacity, M. moniliformis might be used as a highly sensitive free-living bioindicator in terrestrial and urban ecosystems.

Animals↗

A quantitative study of the susceptibility of cockroach species to Moniliformis moniliformis (Acanthocephala).

We exposed 19 species of cockroaches to Moniliformis moniliformis by administering shelled acanthors orally and by injecting hatched acanthors directly into the body cavity. The exposure method had little influence on susceptibility: with one exception, species that were susceptible to oral exposure were also susceptible to injected acanthors and, in no case, did acanthors develop in injected animals when they did not develop in orally exposed conspecifics. We found no support for the hypothesis that the intestine may be a barrier to M. moniliformis establishment in cockroaches. There is, however, clear interspecific variation in susceptibility to M. moniliformis infection.

Administration, Oral↗

Influence of host strain and helminth isolate on the first phase of the relationship between rats and Moniliformis moniliformis (Acanthocephala).

Eleven trials, involving 440 rats bred from 3 laboratory strains and worms from 4 isolates of Moniliformis moniliformis, were carried out with each rat receiving an oral dose of 15 cystacanths. The results showed that the infectivity of the cystacanths was not affected by their age (range 55-194 days) or by their density per cockroach during development (16.1-88.6 cystacanths per cockroach). The numbers of worms per rat recovered at 35 days postinfection (p.i.) were shown to be related to rat strain, with highly inbred strains (PVG and F344) being more supportive of numbers of worms than an outbred Wistar strain. There was no evidence to suggest that the sex of the rats had any influence on the numbers of worms recovered at 35 days p.i. Evidence was obtained to suggest that smaller (younger) rats are likely to support more worms on average than larger (older) rats. There was no evidence of any relationship between worm weight and numbers of worms present per rat on day 35 p.i. Generally, rat strain had little effect on the dry weight (growth) of male M. moniliformis, in contrast to observations made for female worms. The greatest range of worm weights was observed from the recent isolate of the worm (1982) as compared with the well established isolate (1956) and the rats that supported most worms differed from those that harbored the largest worms. Rat sex was not observed to be associated with worm weight. The frequency distributions of numbers of M. moniliformis per rat were not described readily by the negative binomial distribution.

Analysis of Variance↗

Effects of cholinergic drugs on muscle contraction in Moniliformis moniliformis (Acanthocephala).

In whole Moniliformis moniliformis spontaneous muscle contractions were rhythmic; longitudinal contractions were measured with a force transducer. The cholinergic agonists levamisole and nicotine significantly increased muscle tension in whole worms; these contractions were tonic and were antagonised by the ganglionic blocker pentolinium and by piperazine. In addition, levamisole-induced contractions were inhibited by gallamine, hexamethonium, and norepinephrine. In worm segments, where drugs in solution were injected through the worms, acetylcholine (ACh) and nicotinic agonists were effective in causing contractions, whereas muscarinic agonists in concentrations up to 1 mM had no effect. Although muscle contraction in M. moniliformis was induced by nicotinic agonists, these contractions were effectively antagonised by a range of chemicals that block ganglionic, skeletal, and muscarinic sites in vertebrates. The presence of ACh in M. moniliformis and the effects of nicotinic agonists on muscle contraction suggest that ACh is a putative excitatory neurotransmitter.

Acanthocephala↗

Effect of Moniliformis moniliformis density on distribution within the definitive host population (Rattus norvegicus).

The population dynamics of Moniliformis moniliformis was studied in 'free-ranging' laboratory rats, Rattus norvegicus, presented with different relative density levels of M. moniliformis in cockroaches, Periplaneta americana. Changes in selected population parameters of the negative binomial distribution were evaluated as indicators of changes in aggregation. A significant increase in the degree of aggregation of parasites occurred as a result of the increase in relative density of infective stages available to the rats. This increase in aggregation was due to the increase in over-dispersion that occurred in female rats only. The degree of aggregation in females was found to be significantly higher than that in males at both treatment levels. The best indicators of the degree of aggregation were found to be the ratio of the variance to the relative density and the ratio of the log-variance to log-relative density. Changes in k were not correlated with changes in over-dispersion or the relative density.

Acanthocephala↗

Interaction between cadmium exposure and infection with the intestinal parasite Moniliformis moniliformis (Acanthocephala) on the stress hormone levels in rats.

The impact of an infection with the acanthocephalan Moniliformis moniliformis and a simultaneous Cd-exposure on the stress hormone levels of rats was studied. Immediately after the application of cadmium to some rats, cortisol levels in all groups of rats, as quantified by radioimmunoassay (RIA), significantly increased. However, infections with M. moniliformis as well as the uptake of Cd reduced significantly the cortisol release compared to untreated controls. While catecholamine concentrations, as determined by high-performance liquid chromatography (HPLC), showed no clear tendency during the experimental period, the ratio of C(adrenaline)/C(noradrenaline) in the controls showed the significantly lowest value of all four groups after killing the animals. Thus, the acanthocephalan infection as well as the Cd-exposure and the combination of both treatments affect hormone homeostasis in the rats which probably lead to negative effects on the health of the rat. Therefore parasite infections must be carefully considered in environmental impact studies, as an important factor affecting the host's health.

Animals↗

A comparison of biological performances among a laboratory-isolated population and two wild populations of Moniliformis moniliformis.

Divergence of biological performance of a laboratory-reared population of Moniliformis moniliformis (Acanthocephala) was investigated after 31 yr, or approximately 60 generations, of genetic isolation. An isolate of the laboratory-reared population and isolates of 2 wild populations were used to begin 3 independent life cycles that were maintained for 1 generation for interbreeding and life history trait comparison. Both wild population isolates represented populations with open gene flow. One wild population isolate represented a present-day sample of descendants of the parent population of the laboratory isolate. All 3 populations hybridized, and egg production occurred in all mixed-sex pairs of different populations. The 3 populations did not differ significantly in prepatent period, mean daily egg production, or establishment within the definitive host Rattus norvegicus. The 3 populations varied in patent period, but the laboratory-isolated worms differed from the 2 wild population isolates no more than they did from each other. A positive correlation between mean daily egg production and duration of patent period resulted in different cumulative egg productions. A 31-yr period of isolation did not produce greater divergence in a laboratory population of M. moniliformis than occurs between wild populations with respect to the biological parameters measured.

Animals↗

Moniliformis moniliformis infection has no effect on some behaviors of the cockroach Diploptera punctata.

The behavior of the cockroach Diploptera punctata parasitized with the acanthocephalan Moniliformis moniliformis was examined for parasite-induced alterations. No significant difference in behavior was found between parasitized and unparasitized animals in the following behavioral tests: (1) choice of white/black, horizontal/vertical substrate under light and dark conditions; (2) temporal and directional response to a bright light source; (3) choice between light and dark (photophilia); and (4) activity (time spent moving, distance, and velocity). A comparison of uninfected animals under 2 light conditions showed that light affected the activity of uninfected animals and their response to substrate. Diploptera punctata is the first nondomestic cockroach to be examined for behavioral responses to Moniliformis infection. This is the first report of an arthropod in which acanthocephalan infection has failed to alter behavior under at least some common test conditions.

Animals↗

Water balance and its relation to fermentation acid production in the intestinal parasites Hymenolepis diminuta (Cestoda) and Moniliformis moniliformis (Acanthocephala).

Water balance and its relation to carbohydrate metabolism was examined in Hymenolepis diminuta in parallel with the putative osmoconformer Moniliformis moniliformis. Worms were removed from rat intestines, weighed, and incubated (37 C) 1 hr in rat serum and various salines, some with mannitol to vary osmotic concentration from 150 to 400 mOsm/L. Worms were removed at 15-min intervals, weighed, and returned to the test solution. Rat serum and a Ringer's saline (pH 7.4 and 300 mOsm/L) with or without 5 mM glucose were isotonic to M. moniliformis, which behaved like an osmometer, shrinking, or swelling in proportion to external osmotic changes. Hymenolepis diminuta rapidly lost 20-25% wet weight in these solutions and regained lost water when 5 mM glucose was added to the saline. Tapeworms maintained constant body weight between 210 and 335 mOsm/L, but they rapidly gained or lost water outside of this range. Glucose metabolism and uptake of [3H]glucose from the medium increased progressively between 210 and 310 mOsm/L, whereas uptake rates of [3H]leucine, 22Na+, and 36Cl- were not affected. Unbuffered saline (initial pH 6.5 and 300 mOsm/L) had a lower pH (5.0) and higher osmolality (307 mOsm/L) after a 1-hr incubation with tapeworms. Such saline was less hypertonic than unconditioned saline to freshly obtained worms. A Ringer's saline (300 mOsm/L) containing 50 mM acetate- was also hypertonic (greater than 20% weight loss) to tapeworms at pH 7.4, but it was hypotonic (greater than 20% weight gain) at pH 5.0. Isotonicity at 300 mOsm/L was achieved with pH 5.0 and 20 mM acetate-, the approximate pH and fermentation acid concentration in an infected rat intestine. Rats infected with tapeworms (12 days old) were fasted for 2 days. Starved worms were smaller but had the same percentage of body water and internal osmolality as controls. These results show that H. diminuta can regulate its body water content and that water balance is closely related to the fermentation acid concentration and pH of the bathing medium.

Animals↗

Hymenolepis diminuta utilizes the envelope surrounding Moniliformis moniliformis in order to survive in the cockroach host.

The acanthocephalan Moniliformis moniliformis is surrounded by a membranous envelope that protects the parasite from hemocytic attack in the cockroach host. If injected into a cockroach infected with M. moniliformis, hatched oncospheres of the tapeworm Hymenolepis diminuta are able to penetrate this envelope and, once inside, utilize its protective function in order to develop. These "double parasites" were infective to rats.

Acanthocephala↗

[Contribution to the knowledge of immunological relations between Moniliformis moniliformis Bremser, 1811 (Acanthocephala) and Rattus norvegicus Berkenhout, 1769, var. albinos (author's transl)].

Cultured M. moniliformis (Acanthocephala) secrete and excrete antigenic substances. Immunoelectrophoretic analysis of these antigens revealed 14 lines of precipitation, 3 of which represent metabolic antigens. From the remaining 11 somatic antigens, 4 appear to be associated with the lemnisci. As shown by indirect immunofluorescence, specific antibodies predominantly bind to the lemnisci and to the worm's tegument. We therefore propose that metabolic antigens are either formed or stored in these tissues. Specific circulating antibodies have been demonstrated in rats infected with M. moniliformis using indirect immunofluorescence. Reinfection resulted in increased and prolonged antibody production (secondary response). Further immunofluorescence studies indicate that M. moniliformis is able to modify its antigenic set up, particularly between the 3rd and 5th weeks of infection. The immune reaction of the host against this parasite presumably leads to expulsion of worms starting 4 weeks after infection in females and 8 weeks after infection in males. Primary infection of rats with 30 worms elicits immunity. In fact, in preinfected rats only 26.6% of the transferred parasites could settle as compared to 66% following primary infection.

Animals↗

[Contribution to the knowledge of the biology of Moniliformis moniliformis Bremser, 1811 (Acanthocephala). Influence of host resistance of Rattus norvegicus Berkenhout, 1769, on the parasite (author's transl)].

Acquired resistance in rats (SIV 50) during infection with 30 Moniliformis moniliformis has an effect on survival, growth and behaviour of the parasite. We observe an expulsion of worms during infection, starting in the 4th week for female worms but usually after 8 weeks for the males. The density of parasites determines the beginning of the self-cure. Comparing our results with the works of Andreassen (1974a) and Burlingame et Chandler (1941), we observe that the self-cure occurs earlier with doses of 100 larvae than with 30 or 20. Rats with a primary infection show immunity against reinfection. Two weeks after reinfection we observe that only 26% of the parasites are fixed compared to 66% in primary infections. A major effect of immunity is retardation of worm growth. Parasites from reinfections are shorter than those of primary infections. During infection the worm migrate. After the first 3 weeks the male migrate posteriorly and female anteriorly and posteriorly. In reinfections parasites become localized after only 2 weeks. We hypothize that M. moniliformis migrates due to an immunological reaction and inflammatory response of the intestinal mucus but also as a part of its own normal development.

Acanthocephala↗