Jørn Andreassen

Anthelmintic screening of Zimbabwean plants traditionally used against schistosomiasis

Extracts of 23 plant species used popularly against schistosomiasis in Zimbabwe were screened for their anthelmintic effect. Schistosomules of the trematode Schistosoma mansoni and cysticercoids of the cestode Hymenolepis diminuta were studied in vitro. The material consisted of 58 plant extracts, of which 37 killed the newly excysted cysticercoids within an hour, when incubated in a culture medium. Lethal concentrations varied from 0.8 to 103 mg/ml. All plant extracts showed activity against the tapeworms after 24 h. Ten of the best extracts were also tested against schistosomules. Five of these extracts showed activity. Lethal concentrations varied from 0.6 to 33.8 mg/ml of dry plant material. Extracts of stem and root from Abrus precatorius (Fabaceae), of root bark and leaves from Ozoroa insignis (Anacardiaceae) and of root bark from Zizyphus mucronata (Rhamnaceae) gave the best results against tapeworms. The best results against schistosomules were obtained with stem and root extracts from Abrus precatorius (Fabaceae) and stem bark from Elephantorrhiza goetzei (Mimosaceae). Although the activity of root and root bark extracts commonly used in traditional medicine was verified in this study, our results showed that also extracts from leaf and stem can be effective anthelmintics.

Immunological and histopathological reactions of the rat against the tapeworm Hymenolepis diminuta and the effects of anti-thymocyte serum

Summary Anti‐thymocyte‐serum (ATS) treated Wistar rats infected with 100 cysticercoids of the rat intestinal cestode Hymenolepis diminuta showed a delayed destrobilation and expulsion of the worms compared with saline‐treated infected rats. This result strengthens previous evidence of an immunological nature of the destrobilation and expulsion in lumen‐dwelling cestodes—even in their most susceptible hosts. The migration of the worms in the small intestine during the first 20 days of a primary 100‐worm infection is described and the anterior migration of the destrobilated worms to the first 10% of the pylorus is emphasized and compared with similar migrations of the nematode Nippostrongylus brasiliensis in the rat. No serum antibodies were detected using passive cutaneous anaphylaxis and the indirect immunofluorescence test, although the thymus‐independent areas of the mesenteric lymph nodes showed an increase in pyroninophilic cells. In the small intestine, no response to the tapeworm infection could be detected in pyroninophilic cells and globule leucocytes, but mast cell and eosinophilic cell numbers were increased in the saline‐treated infected rats. Although the host responses to H. diminuta are shown to be thymus‐dependent, the possibility of thymus‐independent activity in the host reactions cannot be ruled out.

Complement-mediated lysis in vitro of newly excysted tapeworms: Hymenolepis diminuta, Hymenolepis microstoma, Hymenolepis nana and Hymenolepis citelli

Abstract Bogh H. , Christensen J.P.B. and Andreassen J. 1986. Complement-mediated lysis in vitro of newly excysted tapeworms: Hymenolepis diminuta, Hymenolepis microstoma, Hymenolepis nana and Hymenolepis citelii. International Journal for Parasitology 16 : 157–161. Newly excysted worms of Hymenolepis diminuta were lysed in 50% normal serum from all 13 animal species tested, including man. Since H. diminuta was neither lysed in complement inactivated serum—by heat or adding EDTA, LPS or CVF—nor in C5-deficient mouse serum, it is concluded that the lysis was associated with the complement cascade. It is shown that H. diminuta can activate the complement system via both the classical and alternative pathway. Furthermore, it is indicated that the lysis is independent of serum antibodies. Hymenolepis nana and H. citelli were also lysed in all normal sera tested, eight and six respectively, while newly excysted worms of H. microstoma were lysed in normal sera from 10 mammals and birds, but not in sera from its hosts, the mouse, rat and golden hamster. This indicates that the complement system of these three species differs from that of the other species tested in such a way that H. microstoma is able to avoid lysis in these sera.

Fine Structure of the intestine of the nematodes, ancylostoma caninum and phocanema decipiens

SummaryThe monolayered, intestinal epithelium of the ascaroid, Phocanema decipiens is composed of an innumerable number of uninuclear cuboidal to columnar cells. In the strongyloid, Ancylostoma caninum only the anterior and posterior parts of the intestine are cellular, and are composed of only two longitudinal rows of polynuclear cells, whereas cell boundaries are not found in the middle part of the intestine, i. e. the epithelium is a syncytium. This latter fact is here demonstrated for the first time by electron microscopy in the intestine of nematodes. The basal plasma membrane covering the intestine of both nematodes has invaginations, and towards the perienteric cavity a basal lamella is present. Towards the intestinal lumen the epithelium is covered with microvilli. The central cores of the microvilli as well as the terminal web, with which the cores are connected, appear homogeneous in the strongyloid but are composed of filaments in the ascaroid. In A. caninum, the epithelium is characterized by the presence of mitochondria and rough-surfaced endoplasmic reticulum, the latter often in characteristic whorl-like arrangements. A Golgi complex, various lysosome-like bodies and pigment granules are also present. In P. decipiens the intestinal cells are filled with deposits of glycogen, lipid droplets and lipo-protein granules. The mitochondria are characteristically concentrated in the apical part of the cells and along the cell boundaries. It is pointed out that the structures of the intestinal cells are in accordance with the feeding biology of the nematodes.ZusammenfassungDas einschichtige Darmepithel bei dem Ascaroiden, Phocanema decipiens, besteht aus unzähligen, einkernigen Zellen, kubisch bis säulenartig geformt. Bei dem Stronglyloiden, Ancylostoma caninum, ist das Darmepithel aus nur zwei Längsreihen von vielkernigen Zellen im vorderen und hinteren Teile des Darmes aufgebaut, während es in der Mitte des Darmverlaufes synzytial ist. Dies letztere wird hier zum ersten Male im Nematodendarm elektronenmikroskopisch festgestellt. In beiden Arten wird der Darm von einer basalen Plasmamembrane. mit Invaginationen versehen, bedeckt und von der Leibeshöhle durch eine basale Lamelle abgegrenzt. Das Epithel ist gegen das Darmlumen hin überall mit Microvilli bekleidet. Das Mark von sowohl den Microvilli als dem „Terminalnetz“ („terminal web“), das miteinander in Verbindung steht, ist in Ancylostoma homogen und enthält in Phocanema Filamente. Im Epithel von A. caninum kommen Mitochondrien und ein granuliertes, endoplasmatisches Reticulum vor, das oft in charakteristischer Weise wirbelartig arrangiert ist. Auch ein Golgi-Komplex und verschiedene lysosomähnliche Körperchen samt Pigmentkörnchen kommen in den Epithelzellen vor. In P. decipiens sind dieselben Zellen mit Ablagerungen von Glycogen, Lipidtröpfchen und Lipoproteinkörnchen versehen. Normalerweise sind die Mitochondrien im apikalen Teil der Zellen und den Zellgrenzen entlang konzentriert. Es ist bemerkenswert, wie die Zellstrukturen in Übereinstimmung mit der Ernährungsbiologie der Würmer steht.

Stage–specific antigens of Hymenolepis microstoma recognized in BALB/c mice

Summary Antigenicity of eggs (oncospheres), cysticercoids and adults (with immature segments only) of the bile duct tapeworm Hymenolepis microstoma was analysed using immunoblotting techniques and indirect immunofluorescent antibody (IFA) techniques with immune sera of BALB/c mice (i) infected with different doses of cysticercoids, (ii) during patent or prepatent infection with the lumen phase of the parasite or (iii) sensitized with live or dead eggs. Antibody responses detected by IFA test and immunoblotting showed that antigenicity of eggs (oncospheres) differed from that of cysticercoids and adults. Single worm infections were sufficient to stimulate antibody responses. Mice which had patent infection showed strong antibody responses to all three (egg (oncosphere), cysticercoid, adult) antigens, while mice given two prepatent infections showed some antibody responses to cysticercoid and adult antigens only. Although the normal intermediate hosts of this parasite are arthropods, antibodies to some major egg (oncosphere) antigens were produced in mice given eggs of this parasite orally, either through inoculation of eggs or ingestion of faeces contaminated with eggs. Antibodies were not produced in mice dosed with non–viable eggs. The results are consistent with the hypothesis that cestode parasites express phase– (or stage–) specific antigens.

Responsiveness of congenitally thymus deficient nude mice to the intestinal cestode, Hymenolepis diminuta

Abstract Andreassen J ., Hindsbo O . and Vienberg S . 1982. Responsiveness of congenitally thymus deficient nude mice to the intestinal cestode, Hymenolepis diminuta. International Journal for Parasitology12: 215–219. Serial autopsies showed that most worms from primary infections with 20 Hymenolepis diminuta in nude mice were destrobilated and expelled between days 9 and 20. Faecal examinations and autopsies of 5 cysticercoid infections in nude and normal mice showed that the rejection of H. diminuta was delayed in nude mice compared to normal mice and inhibited by corticosteroid treatments. On the basis of a T-cell dysfunction in nude mice it is suggested that the destrobilation and expulsion of H. diminuta can be mediated by T-cell independent reactions.

Hymenolepis diminuta: The effect of serum on different ages of worms in vitro

Abstract Hymenolepis diminuta : The effect of serum on different ages of worms in vitro . International Journal for Parasitology 16: 447–453. Newly excysted and 2-day-old Hymenolepis dimmuta were lysed completely in 50% fresh rat serum starting from the posterior end. In older worms, 4- to 10-day-old, lysis started in the groove between proglottides at the anterior end of the strobila. The scolex and neck often survived as a destrobilated worm, and in older worms a small amount of the tail-end also avoided lysis. Destrobilation in vitro of worms of increasing age resulted in destrobilated worms of increasing length. Worms which had destrobilated in vivo were either lysed completely or further decollated in fresh rat serum. When 50% fresh rat serum was further diluted with heat inactivated serum, the mean time of lysis of newly excysted worms increased from about 2 min at titer 2 to 40 min at titer 16, where 72% of the worms were lysed. The rest of the worms and worms in titres higher than 16 survived for 24 h. It is suggested that complement could be the effector arm of the host defence system whether specific or not in destrobilation and killing of H. diminuta in its hosts.

Lumen phase specific cross immunity between Hymenolepis microstoma and H. nana in mice

Abstract Ito A. , Onitake K. and Andreassen J. 1988. Lumen phase specific cross immunity between Hymenolepis microstoma and H. nana in mice. International Journal for Parasitology 18 : 1019–1027. When mice inoculated with five cysticercoids of Hymenolepis microstoma were challenged with H. nana , they showed strong resistance to challenges with both eggs and cysticercoids of H. nana from day 20. The immunity became complete from day 30 onward: no tissue cysticercoids or lumenal adults of H. nana were established in these mice. However, when mice were challenged with H. nana 10 or 20 days after 10-day old immature H. microstoma were removed by an anthelmintic, the immunity evoked was directed exclusively against the lumenal phase of the cysticercoid challenge but not the tissue cysticercoids of the egg challenge. When mice experienced the prepatent infection with H. microstoma twice, the immunity evoked was also against the lumenal phase of the egg challenge: the oncospheres developed into tissue cysticercoids but thereafter completely failed to develop into lumenal adult tapeworms. Infection with a single cysticercoid of H. microstoma was shown to be sufficient to evoke immunity against H. nana cysticercoid infections in two strains of mice. Sera from mice which experienced a patent infection with H. microstoma revealed that IgG, IgA, IgM isotypes reacted against oncospheres and cysticercoids of both species, while sera from mice which experienced two prepatent infections reacted with cysticercoids only. Sera from H. microstoma infected mice resistant to H. nana caused precipitations on 4-day-old H. nana in vitro . A correlation exists between the presence of stage specific antibodies and resistance to the different stages.

Course of heavy primary infections and earlier immunologically mediated rejection of secondary infections of Hymenolepis diminuta in mice

Abstract Roepstorff A. and Andreassen J. 1982. Course of heavy primary infections and earlier immunologically mediated rejection of secondary infections of Hymenolepis diminuta in mice. International Journal for Parasitology 12 : 23–28. The worms of heavy (50–100 worms) primary Hymenolepis diminuta infections in inbred C57-mice were 1–2 mm long when growth ceased about day 4. Thereafter the mean length decreased by shrinkage and/or ‘decollation’, the worms moved backwards in the small intestine and were rejected from day 6 to day 10. Heavy secondary infections given 14 days after a heavy primary infection were severely stunted (0.2–0.3 mm) but normally situated in the intestine on day 2 and nearly all were rejected by day 4. Even when the time between the primary and secondary infections was increased to 21 or 42 days, therecovery, position and length of the secondary worms were significantly different from primary infections. These results show that an immunologically mediated memory was involved, and that functional antigens can be released from the scolex and/or the neck alone.

Antagonistic effects of Schistosoma mansoni on superimposed Hymenolepis diminuta and H. microstoma infections in mice.

Patent, but not prepatent, Schistosoma mansoni infections in mice enhanced the expulsion of a superimposed infection with Hymenolepis diminuta. An antagonistic effect was also directed against a superimposed H. microstoma infection in mice harbouring patent S. mansoni infections.