Risa Tiuria

Mucosal mast cells and the expulsive mechanisms of mice against Strongyloides venezuelensis

The possible importance of mucosal mast cells in the expulsive mechanisms of mice against Strongyloides venezuelensis was examined. After a primary infection by subcutaneous inoculation with various doses into C57BL/6 mice, about 50% of the initial dose of infective larvae (L3) became adult worms and, regardless of the dose of infection, they were completely expelled by Day 12 with similar kinetics. Intestinal mastocytosis at the time of expulsion was comparable among groups given different doses of infection. A kinetic study after infection with 2000 L3 in C57BL/6 mice revealed that mastocytosis started from Day 8, rapidly reached a peak on Day 12, and then gradually decreased. The strongest mastocytosis was observed in the upper one sixth of the small intestine where the majority of adult worms parasitized. Over 80% of mast cells induced by the infection were located in the intestinal epithelial layer. When mast cell-deficient W/Wv and their normal littermate +/+ mice were infected with 1000 L3, expulsion was significantly delayed in W/Wv mice, though adult worms were eventually expelled by Day 18 in W/Wv mice. Delayed expulsion as well as defective mast cell responses of W/Wv mice were completely restored by bone marrow grafting 10 weeks prior to infection. These results show that, like S. ratti infection, intestinal mucosal mast cells are important in causing expulsion of S. venezuelensis.

The indian soft-furred rat, Millardia meltada, a new host for Nippostrongylus brasiliensis, showing androgen-dependent sex difference in intestinal mucosal defence

Susceptibility of the Indian soft-furred rat, Millardia meltada, to infection with the intestinal helminth, Nippostrongylus brasiliensis, was examined. After subcutaneous infection with 1500 infective larvae (L3), daily faecal egg output (EPG) of both male and female animals reached a peak at 1 week post-infection (p.i.) with the same magnitude (about 20,000 epg faeces) and then rapidly decreased below detection level at around 2 weeks p.i. In male animals, however, after a transient cessation at 2 weeks p.i., parasite eggs reappeared in faeces 3 weeks afterwards, though the counts were far lower than the first peak. This phenomenon was rarely seen in female animals. High susceptibility of M. meltada to N. brasiliensis was confirmed by worm burdens. About 70% of the initial dose of larvae became adult worms in the intestine of male and female hosts. As suggested by the decline in egg counts, the majority of adult worms were expelled by 2 weeks p.i. The residual worm burden at 2 and 4 weeks p.i. was significantly higher in male than female animals. When orchidectomized males were infected with N. brasiliensis, the magnitude of residual worm burden was significantly reduced. On the other hand, ovariectomy did not affect the number of residual worms in females.

Effect of testosterone on the mucosal defence against intestinal helminths in Indian soft-furred rats, Millardia meltada with reference to goblet and mast cell responses

Effects of testosterone on the mucosal defence mechanisms against intestinal helminths were examined in Millardia meltada. When female M. meltada were treated with testosterone at the pharmacological dose, Nippostrongy‐lus brasiliensis infection persisted for over seven weeks with prominent biphasic pattern of faecal egg production, whereas almost complete expulsion was observed by two weeks in untreated controls. In spite of a biphasic pattern of faecal egg production, the worm burden of testosterone‐treated animals remained constant up to three weeks and then slowly decreased by seven weeks. To see whether or not this delayed expulsion in testosterone treated animals was due to altered cellular responses of the intestinal mucosa, goblet and mast cell responses were examined histologically. At two weeks post‐infection, goblet cell responses at the infected site were significantly lower in testosterone‐treated animals than in controls. In contrast mast cell hyperplasia was comparable between testosterone‐treated and control animals. When Strongyloides venezuelensis, in which expulsion is dependent on mucosal mast cells, were infected concurrently with N. brasiliensis, testosterone‐treated animals could expel S. venezuelensis worms by Day 18, but failed to expel N. brasiliensis. Histologically, mast cell hyperplasia was associated with expulsion ofS. venezuelensis, while goblet cell responses were suppressed. From these results, testosterone seems to suppress proliferation/function of goblet cells but does not affect mast cells ofM. meltada.

Long term survival of ‘damaged’Nippostrongylus brasiliensis adult worms in the testosterone‐treated Indian soft‐furred rat, Millardia meltada

When testosterone‐treated female Millardia meltada were infected with Nippostrongylus brasiliensis, adult worms persisted for over seven weeks. The kinetics of faecal egg counts showed a biphasic pattern having a transient decline at around two weeks post infection (p.i.). Thus the status of  N. brasiliensis adult worms surviving in the small intestines of testosterone‐treated M. meltada was examined. The fecundity and maturity of eggs in the uteri of female adult worms were examined at one, two, three and seven weeks p.i. Both the fecundity and maturity of eggs transiently decreased at two and three weeks p.i. and then completely recovered by seven weeks. Adoptive transfer of  N. brasiliensis adult worms into naive recipients can discriminate the status of worms. Those obtained from the stable phase of a primary infection (‘normal’ worm) can establish and survive in the recipients, whereas those obtained at the time of expulsion (‘damaged’ worm) are rapidly expelled. Therefore, 300 each of N. brasiliensis adult worms collected from the testosterone‐treated female M. meltada at one, two and seven weeks p.i. were transferred intraduodenally into normal rats to determine their status. Those collected at one week p.i. persisted for eight days, indicating that they were still ‘normal’. In contrast, worms collected at two and seven weeks p.i. were expelled within four days, indicating that they had already been ‘damaged’. Moreover, when the ‘damaged’ worms obtained from rats were intraduodenally transferred into testosterone‐treated female M. meltada, they were not expelled, suggesting that testosterone‐treatment affected the final expulsive step, but not the damaging process, of the mucosal defence of M. meltada against N. brasiliensis adult worms.

ENDOPARASIT CACING PADA ORANGUTAN EX-CAPTIVE DI SUAKA MARGASATWA SUNGAI LAMANDAU KALIMANTAN TENGAH INDONESIA

Penelitian ini bertujuan melakukan identifikasi dan mengetahui persentase orangutan yang terinfeksi endoparasit (cacing) pada orangutan excaptive yang berada di Suaka Margasatwa Sungai Lamandau. Sampel feses orangutan yang diperiksa sebanyak 30 individu yang didapatkan di camp Gemini dan Siswoyo. Pemeriksaan feses dilakukan secara makroskopis dan mikroskopis. Pemeriksaan mikroskopis dilakukan dengan menggunakan dua metode yaitu metode Ridley dengan larutan sodium acetate, acetic acid, dan formaldehyde (SAF) fiksatif dan metode apung. Hasil pengamatan menunjukkan adanya infeksi cacing gastrointestinal sebesar 56,7%. Hasil penelitian menunjukkan bahwa orangutan positif terinfestasi telur cacing tipe ascarid; trichurid; dan strongiloid masing-masing sebesar 43,3; 16,7; dan 6,7%. Orangutan dapat mengalami infeksi lebih dari satu jenis tipe telur cacing.

Protozoa Parasitik pada Ikan Sidat (Anguilla spp.) Asal Danau Lindu, Sulawesi Tengah

Infection protozoan parasitic on eels ( Anguilla spp.) from Lindu Lake was affected weight eels and health eels. The protozoan parasitic examinations were collection of eels, inspection eels, observation, measurement, identification of parasites, and staining protozoan used giemsa stained, trematode used semichons’s acetocarmine stained and nematode used clove oil and KOH. The diversity of parasitic protozoan found such as: Myxidium sp., Myxobolus sp., Chilodonella sp., Ceratomyxa sp., Balantidium sp., Henneguya sp., and Glugea sp. The highest prevalence Myxidium sp. in eels was 77% and no protozoan dominated between other parasites. Based on chi-square test, protozoan parasitic had a different preference to organs of eels.