Hymenolepis Nana Eggs Research Articles

Protective action of passively transferred immune serum and immunoglobulin fractions against tissue invasive stages of the dwarf tapeworm, Hymenolepis nana

Serum from mice which received a single oral infection of Hymenolepis nana eggs acquired significant immune activity against subcutaneously growing larvae of this parasite within 7 days, and the maximum level, which was reached by 14 days, was maintained at least 14 days longer. Serum immune activity was manifested by inhibition of larval development at stage I. The time of onset of serum potency demonstrated by passive transfer paralleled the onset of significant resistance to subcutaneous challenge in mice orally infected with a comparable egg dose, and it was concluded these phenomena were causally related. After gel filtration of potent serum, antiparasite activity was found to be associated with the IgG (7S) immunoglobulin fraction.

Hatching requirements of dwarf tapeworm eggs (Hymenolepis nana) in relation to extraintestinal development of larval stages in mice.

It was established that cracked eggs of Hymenolepis nana would develop in the usual manner to the cysticercoid stage within 5 days when injected subcutaneously or intramuscularly into previously uninfected mice. Intestinal enzymes were not necessary to hatching stimulation. The majority of cysticercoids which developed subcutaneously in normal mice survived 3 weeks, relatively few survived 5 weeks, and there was some evidence that several may have survived as long as 8 weeks after infection. Due to the potential for extraintestinal development and survival exhibited by H. nana larval stages, it was suggested that this factor must be considered when attempting to explain the characteristically high level of infection immunity apparent with this parasite.

Loss of pre-irradiation immunity to Hymenolepis nana in the rat-mouse chimera.

SummaryMice were immunized by infection with Hymenolepis nana eggs. Intestinal tapeworms developed and were eventually expelled. The mice were then x-irradiated (950 r) and injected with 40 million syngeneic bone-marrow cells from non-immune mice or with 140 million rat bone-marrow cells. At different times after irradiation and treatment with bone-marrow, groups of mice were given a challenge dose of parasite eggs to test for persistence of immunity. Comparisons between groups were based on the number of worms that developed after the egg-challenge. The mice treated with syngeneic bone-marrow and the rat-mouse chimeras both resisted reinfection when challenged one day after irradiation. Two and three weeks after irradiation, the degree of infection after egg-challenge was greater in the rat-mouse chimeras than in the mice treated with syngeneic marrow. These results indicate that persistence of immunity acquired before irradiation is influenced by the type of bone-marrow implanted after irradiation.

Host resistance to Hymenolepis nana. II. Specificity of resistance to reinfection in the direct cycle

The effect of prior infection with various helminths upon a challenge infection with eggs of Hymenolepis nana was studied in laboratory rodents. The nematodes, Capillaria hepatica, Ascaris lumbricoides, and Trichinella spiralis, were either without effect or produced transient changes in host reactivity to challenge with H. nana. In contrast, prior infection with the cestode species, Hydatigera taeniaeformis, Taenia crassiceps, Hymenolepis microstoma, and H. citelli enhanced resistance to H. nana to a variable degree. A single experiment with H. diminuta was inconclusive. The effects upon H. nana were persistent and appeared to be independent of survival of the primary cestodes. While cross-protection was marked in some experiments, the degree of host resistance elicited was not comparable to that evoked by light primary infections with eggs of H. nana, suggesting that a species-specific factor is important in acquired immunity to this parasite.

Studies on Helminth Immunity

Summary and Conclusions The time interval between initial infection with eggs of Hymenolepis nana and onset of a protective host reaction against a challenge with the same parasite has been restudied. These findings confirm earlier reports of an extremely rapid onset of immunity to H. nana. It is concluded that a local, rapidly mobilized antibody reaction by the immediate cells affected could be responsible in spite of the brief period involved. If this can be proved immunologically, it would provide interesting evidence supporting the concept that locally concentrated cellular antibodies are an important host response to tissue invasion by helminths.

Intestinal Protozoa and Helminths in School Children of Dacca, East Pakistan (East Bengal)

Summary A survey based upon a study of single stool specimens from 300 students in the vicinity of Dacca, East Pakistan, indicates the occurrence of parasites and intestinal fauna in this general area. Entamoeba histolytica, E. coli and Endolimax nana were prevalent, supporting observations indicating that the people, in general, live in an environment which permits effective transmission of certain parasites. The small, non-pathogenic race of E. histolytica was much more common than the larger race. Balantidium coli and Isospora were uncommon with a single infection detected for each. Hookworm, Ascaris and Trichuris occurred in a high percentage of the population and eggs of Hymenolepis nana were found in a single stool. An unidentified acanthocephalan was recorded as well as a single infection with Fasciolopsis and Diphyllobothrium, and three with Haplorchis taichui. All persons studied possessed at least one species of parasite.

Experimental studies on morphological variation in the cestode genus Hymenolepis: III. X-irradiation as a mechanism for facilitating analyses in H. nana

1. 1. Observations have been presented on the morphological effects of exposing eggs of Hymenolepis nana to different doses of X-irradiation ranging from 5 to 40 kiloroentgens. Conspicuous effects in cysticercoids were malformations and arrested development. Abnormal appearing cysticercoids failed to develop to adults when fed to albino mice. 2. 2. No adult cestodes were obtained, either directly or indirectly, from eggs exposed to more than 30 kr. 3. 3. Below the lethal level of radiation, no abnormalities were observed which could not be found in non-irradiated specimens. Analyses indicated that X-irradiation induced an increase in the frequency with which a given variant characteristic occurred and that the frequency tended to be proportional to the dose received. 4. 4. Data on frequency of occurrence, according to the r-dose received, have been presented for each of five variant characteristics. Comparisons made with non-irradiated specimens indicated that reliable estimates of the frequency with which a given morphological variant characteristic occurs in the normal population can be obtained by extrapolation of the irradiation data. Experimental evidence has been given in support of the proposed hypothesis that X-irradiation may serve as a useful tool in facilitating determinations of the nature, extent and possible directional trends of morphological variations in a population of cestodes.

Acquisition of intestinal protozoa and helminths by young children in a typical village of lower Egypt.

SummaryChildren of three different age groups (1 to 6 months, 13 to 24 months and 26 to 47 months of age at beginning of survey) were studied weekly for their intestinal fauna for a period of 16 weeks. The intestinal fauna of the youngest group were limited quantitatively and qualitatively and only flagellate protozoans were detected. Stool examinations of children 13 to 24 months of age indicated that the period of 15 to 20 months was very important from the standpoint of general establishment of intestinal fauna in a child. Flagellates increased in number, amebas were detected and the eggs of Ascaris, Enterobius and Hymenolepis nana were passed with feces. At the age of 16 to 18 months Entamoebs histolytica became established, the rate of infection increasing rapidly the following 2 years. In the oldest age group protozoan and helminth populations increased markedly and none of the 28 children escaped invasion by intestinal fauna. A total of nine species of protozoa, plus both the large and small races of E. histolytica and six different helminths were found in the latter age group by the time this study terminated. Although the village of Sindbis lies in an endemic area, neither of the two schistosomes common to Egypt were found.

On the Development of the Human Hymenolepis nana (Siebold 1852) in the White Mouse; with remarks on “H. fraterna,” “H. longior” and H. diminuta

1. Out of 57 mice (previously ascertained to have been free from “H. fraterna”) 30 were fed on fresh eggs of Hymenolepis nana, the other 27 serving as controls. Out of the 30 egg-fed mice, only 7 were found to be infected (23·3 per cent.) when examined from thirteen to twenty-six days afterwards. None of the 27 control mice showed infection.2. This low percentage of infection (when compared with the 90 per cent, infection obtained in my previous work when I fed 20 mice on “H. fraterna” eggs) is probably due to one or more of three factors: (a) change of host (Grassi records that he found it very difficult to infect wild rats with “H. fraterna” eggs obtained from tame rats and in this case the animals were of the same or closely allied species); (b) the full-grown adult condition of the mice; (c) the perfect health of the mice, due to having been supplied with vegetable food (Vitamin B) every day, this condition rendering the mice refractory to infection. In my previous work the mice were in poor condition owing to deficiency of Vitamin B.3. The proof that rats and mice can be infected with H. nana eggs from Man, the identity of structure of the two parasites and their eggs and their uniform geographical distribution render it practically certain that H. nana and “H. fraterna” are one and the same species. The fact that up to the present there is practically no evidence that Man can be infected with eggs derived from rats or mice does not militate against this conclusion.4. Mature specimens of H. nana found in tame mice vary enormously in size (as already indicated by Joyeux)—between 7 mm and 80 mm. (measured in balsam) in length. “H. longior” (Baylis, 1922) does not exist as a distinct species.5. I failed to infect two Cercopithecus monkeys fed with a plentiful supply of fresh H. nana eggs (from Man).6. Experiments are described which confirm Joyeux's statement that H. diminuta (of the mouse), unlike H. nana, does not possess a direct one-host life-cycle.

THE PRESENCE OF HYMENOLEPIS NANA IN PORTO RICO

ABSTRACT Hymenolepis nana has been reported so often in the United States that it is now regarded as one of the commonest tapeworms infesting man. It has not, as far as we have been able to ascertain, been reported before from Porto Rico. The cases here presented should therefore be of some interest as further indicating the cosmopolitan distribution of this parasite.In examining the forty-seven inmates of the boys orphan home in Hatillo for hookworms, the eggs of Hymenolepis nana were discovered in the stools of three of the boys. This home is managed entirely by local people, and admits boys from 6 to 12 years of age. One of the boys had been in the home for three years, the other two for two years. None of the boys or the director have ever been off the island. Their only contact with outside people is in the local schools.