Worm Recovery Rate Research Articles

Anticestodal activity of Adhatoda vasica extract against Hymenolepis diminuta infections in rats

Aim of this study Adhatoda vasica Nees has been commonly used in the indigenous system of medicine of Naga tribes in India for curing intestinal worm infections. In this study the anticestodal efficacy of Adhatoda vasica leaf extract was evaluated using Hymenolepis diminuta-rat experimental model. Materials and methods The anticestodal efficacy of leaf extract was determined by monitoring the eggs per gram (EPG) of faeces counts and percentage worm recovery rates following treatment with methanol leaf extract of this plant to different groups of rats harbouring immature and mature Hymenolepis diminuta infections. Results The result indicated 800 mg/kg double dose of extract has profound efficacy against mature worms, where the EPG count was reduced by 79.57% and percentage worm recovery rate by 16.60%. These effects were better than treatment with 5 mg/kg single dose of praziquantel, the standard drug. In case of efficacy against immature worms, the extract showed a significant reduction in worm recovery rate (from 100% in control to 20.00% at 800 mg/kg dose of extract). Conclusion The study shows that the leaf extract of Adhatoda vasica possesses significant anticestodal efficacy and supports its use in the folk medicine.

Haplorchis taichui: Worm recovery rate and immune responses in infected rats ( Rattus norvegicus)

Worm recovery rate, mucosal mast cells (MMCs), eosinophils and serum IgE concentration in rats were investigated after orally feeding 300 Haplorchis taichui metacercariae to male rats. The duodenal, jejunal and ileal tissue sections were stained with 1% alcian blue and 0.5% safranin-O for MMC count. Eosinophil count and the serum IgE concentration assay were measured from cardiac puncture blood. The average worm recovery rates were 20.00%, 13.00%, 0.67%, 1.67% and 0.00% on day 3, 7, 14, 21 and 28 post-infection (PI), respectively. The number of MMCs in the infected rats were significantly higher than in the controls ( P < 0.01), reaching a peak on day 21 PI. They decreased thereafter, with the decline in worm recovery. Eosinophil count and Serum IgE concentration were also increased but not significantly higher than the controls. However, they showed a positive relationship to worm recovery. It could be concluded from the results that MMCs, eosinophils and IgE may play an important role in the expulsion of H. taichui from rat intestine. However, the mechanism by which the MMC result in the helminth expulsion still need to be understood, and it is recommended that other cells such as goblet cells be studied further.

Immune response and inhibitory effect of ketotifen on the BALB/c and C3H/HeN mice infected with Echinostoma hortense

Although Echinostoma hortense is one of the intestinal trematodes with a high infection rate in South Korea, the exact immune response against E. hortense infection has yet to be fully investigated. In the present study, we investigated differential susceptibilities in two different strains of micenamely, BALB/c (H-2d) and C3H/HeN (H-2k) mice. Likewise, we investigated the effects of ketotifen, an antiallergic drug, on the immune response against E. hortense infection. The worm recovery rate of the C3H/HeN mice was much higher than that of the BALB/c mice. The messenger ribonucleic acid (mRNA) expressions of interleukin (IL)-4 and IL-5 in the BALB/c mice were stronger than that of the C3H/HeN mice after E. hortense infection, but IL-1beta and tumor necrosis factor (TNF)-alpha expressions in the BALB/c mice were weaker than that of the C3H/HeN mice after E. hortense infection. The number of goblet cells and eosinophils increased after E. hortense infection in the BALB/c and the C3H/HeN mice. The worm recovery rate was higher and lasted longer in the ketotifen-treated mice in comparison to the untreated mice. Ketotifen suppressed the mRNA expression of IL-4 and IL-5 in the BALB/c mice, but did not in the C3H/HeN mice. The IL-1beta expressions were inhibited by ketotifen in the two strains, but TNF-alpha expression was inhibited in the C3H/HeN mice after ketotifen treatment. In addition, ketotifen inhibited the increase in eosinophils and goblet cells in varying degrees, depending on the strain. In summary, the immune sensitivity against E. hortense depends on the species of the host. The ketotifen treatment administered on the infected mice differently blocked the immune response against E. hortense infection.

Development of Centrocestus armatus in different final hosts

In this study, Centrocestus armatus metacercariae were fed orally to hamsters, albino rats, mice, and chicks. Animals were sacrificed and dissected at 1, 3, 5, 7, and 14 days post-infection to determine the development and recovery rate of worms. Results indicated that the average worm recovery rate in hamsters was 25% on the first day post-infection and recovery continued until the 14th day with a gradual decrease in the percentage. Worms were also recovered from mice and albino rats from the first until the third day post-infection, but no worms were recovered thereafter. In chicks, worms were not observed on first day but recovery was positive at 12 h post-infection. Among the four animal hosts, feces from hamsters were the only ones positive for eggs; these were initially observed from the third day and recovery continued until 14 days post-infection. In our study, hamsters are the animal model most suitable for the study of C. armatus when compared to rats, mice, and chicks.

Anticestodal Efficacy of Lasia spinosa. Extract Against Experimental Hymenolepis diminuta. Infections in Rats

The use of Lasia spinosa. (L.) Thwaites (Araceae) leaves in the treatment of intestinal worm infections is a common ethnobotanical practice in the Naga tribes of India. In the current study, the anticestodal efficacy of L. spinosa. leaf extract was investigated against a tapeworm using Hymenolepis diminuta.–rat animal model. The anticestodal effects of L. spinosa. leaf extract was determined by monitoring the eggs per gram of feces (EPG) counts and percentage worm recovery rates after treatment with leaf extract in single and double doses of 200, 400, 800, and 1600 mg/kg that were given orally for 5 days to the rats harboring immature and mature worms. The effect of plant extract was found to be dose-dependent, and double doses showed better efficacy as compared with single doses. In the case of infections with immature worms, 1600 mg/kg double dose of L. spinosa. leaf extract reduced the fecal egg counts of H. dimunta. by 80.8% and worm recovery rate by 16.7%, respectively. Praziquantel, the standard anticestodal drug given in 5 mg/kg single dose, reduced the fecal egg count by 83.2% and worm recovery rate by 16.7%. In the case of efficacy against mature worms, 1600 mg/kg double dose of leaf extract reduced the fecal egg counts of H. diminuta. by 94.9% and worm recovery rate by 8.5%, respectively. Praziquantel (5 mg/kg, single dose) reduced the fecal egg counts by 95.1% and worm recovery rate by 16.7%. The study suggests that the leaf extract of L. spinosa. possesses significant anticestodal efficacy and supports its use in folk medicine.

Anticestodal property of Strobilanthes discolor: An experimental study in Hymenolepis diminuta—rat model

Use of Strobilanthes discolor T. Anders leaves in the treatment of intestinal worm infections is a common ethnobotanical practice in the Naga tribes of north-eastern part of India. In the present communication the anticestodal efficacy of Strobilanthes discolor leaf extract was investigated using Hymenolepis diminuta—rat experimental model. The effects of leaf extract were adjudged by monitoring the eggs per gram of faeces (EPG) counts and percentage worm recovery rates following treatment with methanol leaf extract of this plant to different groups of rats harbouring Hymenolepis diminuta infections. The leaf extract showed significant reductions in EPG counts as well as in recovery of surviving worms at autopsy. A notable result of the extract's efficacy was observed against the larval stages of parasite, where no single worm was recovered at its 800 mg/kg dose administered twice daily for 3 days. Effects of plant extract on adult stages were almost comparable with that of a standard drug, Praziquantel. The study suggests that the leaf extract of Strobilanthes discolor possesses significant anticestodal activity and supports its use in the folk medicine.

SUSCEPTIBILITY OF INBRED MOUSE STRAINS TO INFECTION WITH THREE SPECIES OF METAGONIMUS PREVALENT IN THE REPUBLIC OF KOREA

Susceptibility of inbred mouse strains to Metagonimus yokogawai, Metagonimus miyatai, and Metagonimus takahashii infections was studied using BALB/c, ddY, C57BL/6J, C3H/HeN, and A/J mice, with H-2 haplotypes d, s, b, k, and a, respectively. Two hundred metacercariae were orally fed to each mouse, and the worm recovery rates (WRR), worm dimensions, and intrauterine egg numbers were measured at days 3, 7, 14, 21, and 28 postinfection (PI). On day 14 PI, the WRR of M. yokogawai was highest in ddY mice (average, 62.2%); those of M. miyatai and M. takahashii were highest in ddY (19.5%) and BALB/c mice (10.4%), respectively; worm maturation was best in C3H/HeN (M. yokogawai), C57BL/6J (M. miyatai), and ddY mice (M. takahashii). All mouse strains showed higher susceptibility to infection with M. yokogawai than with M. miyatai or M. takahashii. The results show that susceptibility of mice to Metagonimus infection varies according to mouse strain and parasite species but is suggested to be independent of the mouse H-2 haplotype.

Anticestodal Activity of Trifolium repens. Extract

ABSTRACTTrifolium repens. L. is an herbal plant that is used in the folk medicine of the Naga tribes of India as a deworming remedy. This study deals with evaluating its anticestodal activity using experimental Hymenolepis diminuta. Rudolphi infections in albino rats. Doses of T. repens. aerial shoots extract 200 and 500 mg/kg reduced the mean fecal egg counts of H. diminuta. by 47.72% and 54.59% and worm recovery rate by 60.00% and 40.00%, respectively. Praziquantel, the standard cestocidal drug, reduced the mean fecal egg count by 65.90% and worm recovery rate by 26.67%. The study suggests that the aerial shoots of T. repens. bear anticestodal properties and supports its use in the traditional medicine system.

Delayed macrofilaricidal activity of diethylcarbamazine against Brugia pahangi in Mongolian jirds

The macrofilaricidal activity of diethylcarbamazine (DEC) was confirmed in jirds infected with Brugia pahangi. Seventy jirds were inoculated subcutaneously with 100 infective larvae. At 20 weeks post-infection, the microfilaraemic jirds were divided into two groups, untreated and treated. For the treated group, 200 mg kg(-1) of DEC was injected intraperitoneally for 5 consecutive days. One, 4, 8, 12, 16 and 27 weeks after the final treatment, 4-7 jirds in each group were sacrificed to measure adult worm burdens. The number of adult worms recovered from treated jirds was comparable to controls at earlier necropsy (1 and 4 weeks post-treatment). However, at late necropsy (8 weeks and later) the recovery rate of adult worms in treated jirds was significantly lower than that in untreated controls, indicating an adultcidal effect of DEC. The present study demonstrates that DEC requires 8 weeks to kill B. pahangi adult worms in jirds and that the Mongolian jird is a useful model for screening antifilarial activity.

Increased early local immune responses and altered worm development in high-dose infections of mice susceptible to the filaria Litomosoides sigmodontis.

The relationship between the number of larvae inoculated and filarial infection outcome is an important fundamental and epidemiological issue. Our study was carried out with BALB/c mice infected with the filaria Litomosoides sigmodontis. For the first time, an immunological analysis of infection with various doses was studied in parallel with parasitological data. Mice were inoculated with 200, 60 or 25 infective larvae (third stage larvae, L3), and monitored over 80 days. At 60 h post-inoculation the immune response was stronger in the 200 L3 group than the 25 L3 group. Cells from lymph nodes draining the site of inoculation proliferated intensely and produced large amounts of IL-5 and IL-4. In the pleural cavity, leukocyte populations accumulated earlier and in larger quantities. IgG1, IL-4 and IL-10 serum concentrations were transiently higher. During the first 10 days the worm recovery rates were identical in all groups, but decreased thereafter in the 200 L3 group. In this group, the development of the worms was altered, with reduced lengths, diminished intra-uterine production of microfilariae and abnormalities of male copulatory organs. Whereas mice inoculated with 25 L3 became microfilaraemic, only one third reached patency in the 200 L3 group. However, detrimental effects of high numbers of worms are not seen in studies using different inoculation protocols. This suggests that the very early events determine subsequent immune response and infection outcome rather than competitive interactions between the worms.

Growth and development of Massaliatrema misgurni (Trematoda: Heterophyidae) in mice and its metacercarial morphology

The morphology of metacercariae of Massaliatrema misgurni Ohyama et al. (Ohyama et al., Parasitol Int 2001; 50; 267–71) was described, and their infectivity, egg output, growth and development in mice until day 35 post infection (PI) were studied. Metacercarial cysts from loaches imported from China to Japan were 199–349 μm in diameter and consisted of a very thick translucent outer layer and a refractile inner layer. Excysted metacercariae basically had the shape of miniature adults, and a pair of pre-developed testes but no other genital organs were recognized. The worm recovery rate from mice was 36.7–51.7% during days 3–7 PI, and decreased remarkably to 2.5 and 1.7% at days 28 and 35 PI. The prepatent period was 3–4 days, and the egg output quickly increased and sustained high levels at days 5–7 PI, then decreased suddenly at day 8 PI, and continued at a low level until day 28 PI. The size of the body and inner organs such as the oral sucker, pharynx, acetabulum, testes, ovary and seminal receptacle quickly increased until day 3 PI, and sustained at a plateau level until day 21 PI except testes which gradually decreased until 21 PI. The number of the uterine eggs increased with a short time lag compared to other genital organs and sustained a plateau level until day 21 PI. Compared with other Heterophyidae species, M. misgurni was characterized by the remarkably fast growth and development.

Development of resistance to reinfection by Clonorchis sinensis in rats

We investigated the induction of resistance to Clonorchis sinensis infection by prior infection in rat and hamster models. Animals were challenged with C. sinensis metacercariae, then treated with praziquantel and reinfected. Worm recovery rate in reinfected animals was used to estimate resistance to reinfection. The determined resistance rates to reinfection in rats and hamsters were 97.7% and 10.3%, respectively. In rats, cure from the primary infection of C. sinensis increased resistant to reinfection, and the greater the worm burden and the longer the duration of primary infection, the higher was the resistance rate. For primary infection doses of 10, 40 and 100 metacercariae per rat, the resistance rates were 87.4%, 93.8% and 98.4%, respectively. The resistance rates in rats after 2 or 8-week primary infection were 78.7% and 95.3%, respectively. All worms recovered from reinfected rats were immature. When cured rats were administered with methylprednisolone, resistance to reinfection became impaired. These findings indicate that rats develop a high degree of resistance to reinfection by C. sinensis after cure. The growths and maturations of reinfected worms were also impaired.

Susceptibility of several strains of mice to Echinostoma hortense infection

Susceptibilities of 5 different mice strains, including C3H/HeN, BALB/c, C57BL6, FvB and ICR, to Echinostoma hortense infection, was evaluated. The worm expulsion rate, worm size and egg production were observed from 1 to 8 weeks after infection with 30 metacercariae. C3H/HeN and ICR mice showed the highest worm maturation rates. The worm recovery rate and the number of eggs per gram (EPG) of feces was also higher in C3H/HeN and ICR mice than in BALB/c, C57BL6, and FvB mice. It is suggested that E. hortense is highly infectious to ICR and C3H/HeN mice, but not to the other strains of mice. Based on the results obtained, we believe that the susceptibility of different mouse strains to E. hortense infection is dependent on the genetic and immunologic background of mice.

Role of intestinal goblet cells in the expulsion of Gymnophalloides seoi from mice.

Role of intestinal goblet cells (GCs) in the expulsion of Gymnophalloides seoi was studied using 4 strains of mice, ICR, C3H/ HeN, BALB/c, and C57BL/6, after infection with 200 metacercariae isolated from oysters. On day 7 postinfection (PI), significantly higher (P < 0.05) worm recovery rates (WRRs) were observed in ICR (29.5 +/- 12.0%) and C3H/HeN (14.8 +/- 8.2%) than in BALB/c (5.7 +/- 5.3%) and C57BL/6 (0.8 +/- 1.1%) mice. Alteration of the GC mucins was marked in C57BL/6 mice. On day 14 PI, 5.2 +/- 5.2% and 0.6 +/- 0.7% of worms were recovered only from ICR and C3H/HeN mice. When C57BL/6 mice were immunosuppressed with prednisolone, WRR on day 7 PI increased to 11.7 +/- 13.9%, whereas the GC hyperplasia and mucin alteration diminished significantly. The results suggest that expulsion of G. seoi from the intestine is dependent on immune responses of the host, and GCs may be an important effector.

Echinostoma luisreyi n. sp. (Platyhelminthes: Digenea) by light and scanning electron microscopy.

The entire life cycle of the Brazilian Echinostoma luisreyi n. sp., of the 37-collar spine E. revolutum group, has been observed under experimental conditions. The snail Physa marmorata serves as its first natural intermediate host. This species and the planorbid Biomplalaria glabrata act as experimental second intermediate hosts. The worm recovery rate was 51.3 and 0.6% for mice and hamsters, respectively, but the infection did not develop in the quail Coturnix coturnix. The natural vertebrate host is not known. The most important morphological character of the new species separating it from the other Echinostoma species studied is the oral corner spines that increase in size from the latero-oral to the ventro-oral regions. The ratio of the sizes of the smaller oral spines and the larger aboral ones was 1.7:1.0. Also, the excretory pore is radially wrinkled and dorsally subterminal. Images obtained by scanning electron microscopy confirmed the characters that differentiate the new species and the most closely related species.

Combined treatment with interleukin-12 and mebendazole lessens the severity of experimental eosinophilic meningitis caused by Angiostrongylus cantonensis in ICR mice.

Angiostrongylus cantonensis is the major cause of eosinophilic meningoencephalitis cases in Taiwan. Mice were orally infected with 35 infective larvae. One group of mice were given a single dose of mebendazole (20 mg/kg of body weight) per os at various times and examined at 14 days postinfection (dpi) for worm recovery rate and pathological studies. A 94 to 97% reduction in worm recovery was observed when medication was given at 4 to 5 dpi. Sections of the brains revealed that untreated infected mice developed typical severe eosinophilic meningoencephalitis. Meninges of these mice were thickened by massive infiltration of eosinophils, whereas only moderate pathological change was observed in the brains of mice that were treated with mebendazole at 4 dpi. Infected mice that received daily injections of 10 ng of interleukin-12 (IL-12) only for various numbers of days also exhibited moderate pathological changes in the brain. Eosinophil infiltration in the brains of these mice was low, and severe mechanical injuries in the parenchyma were observed. Treatment with mebendazole in combination with IL-12, however, resulted in low levels of worm recovery and dramatic lessening of the eosinophilic meningitis. A reverse transcriptase PCR assay of mRNA expression in the brain also revealed that the use of IL-12 had shifted the immune response of the mouse from Th2 type to Th1 type. This study could be used in developing strategies for the treatment of human angiostrongylosis.

Effects of anti-allergic drugs on intestinal mastocytosis and worm expulsion of rats infected with Neodiplostomum seoulense.

The effects of anti-allergic drugs on intestinal mastocytosis and the expulsion of Neodiplostomum seoulense were observed in Sprague-Dawley rats, after oral infection with 500 metacercariae. The drugs used were hydroxyzine (a histamine receptor H1 blocker), cimetidine (a H2 blocker), cyclosporin-A (a helper T-cell suppressant), and prednisolone (a T- and B-cell suppressant). Infected, but untreated controls, and uninfected controls, were prepared. Worm recovery rate and intestinal mastocytosis were measured on weeks 1, 2, 3, 5, and 7 post-infection. Compared with the infected controls, worm expulsion was significantly (P < 0.05) delayed in hydroxyzine- and cimetidine-treated rats, despite mastocytosis being equally marked in the duodenum of all three groups. In the cyclosporin-A- and prednisolone-treated groups, mastocytosis was suppressed, but worm expulsion was only slightly delayed, without statistical significance. Our results suggest that binding of histamine to its receptors on intestinal smooth muscles is more important in terms of the expulsion of N. seoulense from rats than the levels of histamine alone, or mastocytosis.

Experimental infection of laboratory animals and sheep with Gongylonema pulchrum in Japan.

Japanese White rabbits, Wistar rats, ddY mice, Suffolk sheep, and a domestic cat were each orally inoculated with 20-140 third-stage larvae (L3) of Gongylonema pulchrum, isolated from naturally infected dung beetles captured in Aomori Prefecture. Worm recovery rates were 40.0-72.0% in rabbits at 7, 14, and 19 weeks post-infection (PI) and 3.3-25.0% in rats at 19 weeks PI. Those in 2 sheep at 7 weeks PI showed 53.6% and 29.3%. No worms were recovered from the mice and the cat. In the susceptible animals, many worms were found in the esophagus, and a few were present in the pharyngeal mucosa, tongue, buccal mucosa, and cardiac portion of the stomach wall. No distinct morphological differences were observed in the worms from rabbits and sheep. These results indicate that rabbits are very suitable experimental definitive hosts for G. pulchrum.

Effects of gamma-irradiation on the infectivity and chromosome aberration of Clonorchis sinensis.

Effects of gamma irradiation on the worm survival and chromosomal aberration of Clonorchis sinensis were studied. The metacercariae irradiated with various amounts of gamma radiation (ranging from 5 Gy to 50 Gy) were fed to rats, and the effects were compared with those of non-irradiated controls. Recovery rates of adult worms in irradiated groups were reduced gradually as increasing of the irradiation doses. No worm was recovered from rats which were fed with 50 Gy irradiated metacercariae. The chromosome number was 2n = 56 in all worms from all experimental groups. However, the groups irradiated with 20 Gy, 25 Gy or 30 Gy showed variations in the chromosome number, depending on different cells in the same individual. Radiation doses used in this study did not appear to induce chromosome aberrations, however, irradiation with 30 Gy showed slightly reduced chromosome size.

Experimental evidence of hybrid breakdown between the two geographical strains of Schistosoma intercalatum.

Reciprocal crosses (Schistosoma intercalatum male Zaire x S. intercalatum female Cameroon: S. intercalatum female Zaire x S. intercalatum male Cameroon) were produced in 10 mice by exposing each mouse to 60 male cercariae of one isolate and 60 female cercariae of the other isolate, and vice versa. Hybrid generations originating from the two crosses were established. The infectivity of the F1, F2, F3 and F4 hybrid generations were evaluated after exposing snails individually to 5 miracidia. A comparative histological study of snails infected with F2 and F4 hybrid sporocysts from both crosses was made to assess abnormalities in the intramolluscan development of the hybrids. The worm recovery rate and fecundity were measured by comparing the fitness of the mid-parents with that of the hybrids. S. intercalatum Cameroon was compatible with Bulinus forskalii and incompatible with B. globosus whereas S. intercalatum Zaire was compatible with B. globosus and incompatible with B. forskalii. In the case of S. intercalatum male Cameroon x S. intercalatum female Zaire, hybrid miracidia develops in both B: forskalii and B. globosus in F1, F2 and F3 generations. The infection rate was much lower for B. globosus and F2 and F3 generations produced few cercariae (less than 30 cercariae in overall per snail) and F4 miracidia were only infective to B. forskalii again producing few cercariae. At 40 days post-infection the sporocyst contains masses of acidophilic granules originating from the breakup of pycnotic nuclei. Similarly the F1, F2 and F3 miracidia of the reciprocal cross (S. intercalatum male Zaire x S. intercalatum female Cameroon) exhibited a dual infectivity for B. forskalii and B. globosus, but cercarial productivity was low (less than 30 cercariae overall per snail for F2 and F3 generations). Histological studies demonstrated sporocyst degeneration in snails infected with F4 generation. In the definitive host, the F, generation (both crosses) exhibited hybrid vigour in that the worm return was greater than that of the mid-parent, F2 and F3 generations. No significant difference in fecundity was demonstrated between the parental strains and the F1 and F2 generations, yet egg production of the F3 generation was significantly lower. It is apparent that there is a post-zygotic barrier in the crosses of S. intercalatum Zaire and S. intercalatum Cameroon from the F2 generations onwards, and sterility of the F4 hybrid sporocyst supports the concept of the existence of 2 distinct taxa.