Effect of mice Taenia crassiceps WFU cysticerci infection on the ovarian folliculogenesis, enzyme expression, and serum estradiol.

The murine infection with Taenia crassiceps WFU (T. crassiceps WFU) cysticerci has been widely used as an experimental model to better understand human cysticercosis. Several reports have established that the host hormonal environment determines the susceptibility and severity of many parasite infections. Female mice are more susceptible to infection with T. crassiceps cysticerci suggesting that a rich estrogen environment facilitates their reproduction. Ovarian androgens and estrogens are synthesized by key enzymes as P450-aromatase and 17α-hydroxilase/17, 20 lyase (P450C17). The aim of this study was to determine the effect of chronic intraperitoneal infection of T. crassiceps WFU cysticerci on mice ovarian follicular development, ovulation, the expression of ovarian P450-aromatase and P450C17, and serum 17ß-estradiol, key enzymes of the ovarian steroidogenic pathway. To perform this study ovaries and serum were obtained at two, four and six months from T. crassiceps WFU cysticerci infected mice, and compared to those of healthy animals. The ovaries were fixed and processed for histology or lysed in RIPA buffer for Western blot using specific antibodies for P450C17 and P450-aromatase. 17ß-estradiol serum concentration was measured by ELISA. The results showed that the infection with T. crassiceps WFU cysticerci significantly reduced the number of primordial and primary follicles after two months of infection. Through the course of the study, the corpus luteum number began to decrease, whereas atretic follicles increased. The expression of ovarian P450C17 and P450-aromatase as well as serum E2 concentration were significantly increased in the infected group compared to control. These findings show that chronic infection with Taenia crassiceps WFU may alter the reproductive functions of the female mice host.

Hippocampal sclerosis induced in mice by a Taenia crassiceps metacestode factor.

An experimental Taenia crassiceps mouse model was used to assess the role of Taenia solium metacestode factor (Fac) in human neurocysticercosis. Intraperitoneal infection with T. crassiceps metacestodes or subcutaneous inoculation with a T. crassiceps metacestode factor (Fac) produced significant impairment of performance (learning) in the Barnes maze and induced bilateral hippocampal sclerosis in mice. Several staining techniques revealed important cell dispersion, extensive apoptosis and cell loss in the dentate gyrus, hilus and CA1-CA3 regions of both hippocampi, as well as intense deterioration of the adjacent cortex. An outstanding disruption of its histoarchitecture in the surrounding tissue of all these regions and apoptosis of the endothelial cells were also observed.

Mathematical model of the life cycle of taenia-cysticercosis: transmission dynamics and chemotherapy (Part 1).

BACKGROUND: Taenia solium is the aetiological agent of human taeniasis, pig cysticercosis and human neurocysticercosis, which are serious public health problems, especially in developing countries. METHODS: A mathematical model of the transmission dynamics of taeniasis-cysticercosis is formulated. The model consists of a coupled system of differential equations, which are density-dependent equations for describing the flow of the parasite through the life cycle. The model is hybrid since it comprises deterministic equations with stochastic elements which describe changes in the mean parasite burden and incorporates the overall pattern of the parasites' distribution. RESULTS: Sensitivity and bifurcation analyses were carried out to determine the range of values of the model. The model can reproduce the observed epidemiological patterns of human taeniasis, pig and human cysticercosis. For example, for a wide range of parameter values, the mean intensity of adult worms tends to rapidly stabilize in one parasite per individual host. From this model, we also derived a Susceptible-Infected model to describe the prevalence of infection in humans and pigs. Chemotherapeutic interventions against pig cysticercosis or human taeniasis may reduce rapidly and effectively the mean intensity of human taeniasis, pig cysticercosis and human cysticercosis. This effect can be achieved even if the protective efficacy of the drug is of the order of 90% and the coverage rate is 90%. This means that health in humans infected either with adult worms or cysticerci may be achieved by the application of anthelmintic drugs against pig cysticercosis. However, treatment against human cysticercosis alone, does not influence neither human teniasis nor pig cysticercosis. This is because human cysticercosis infection does not influence the value of the basic reproductive number (Ro). CONCLUSIONS: Even coverage of 100% in the administration of anthelmintics did not eliminate the infection. Then elimination of the infection in all hosts does not seem a feasible goal to achieve by administering only chemotherapeutic interventions. Throughout the manuscript a discussion of our model in the context of other models of taeniasis-cysticercosis is presented.

Relationships among neuroscore, magnetic resonance imaging features, and intracranial pressure in sheep affected by slow-growing brain lesions.

Diagnosing high intracranial pressure by clinical and diagnostic imaging is particularly challenging for chronic or slow-growing lesions. The aim of this prospective case-control study is to determine whether the neuroscore and brain magnetic resonance imaging (MRI) are related to the direct measurement of intracranial pressure in sheep affected by intracranial slow-growing lesions due to chronic cerebral coenurosis (Coenurus cerebralis). Seventeen affected and 10 control sheep were included. All animals underwent a neurological examination, MRI of the brain, and direct measurement of intracranial pressure. The severity of clinical signs and MRI findings were scored. Data were statistically analyzed. The invasive intracranial pressure value was higher in affected animals. A severely altered neuroscore is related to an increased intracranial pressure beyond the normal threshold (P < 0.05). The volume of the calvarium was larger in affected animals than in control animals (P = 0.0001) and was positively influenced by the presence and volume of the parasitic cyst (r = 0.7881, P < 0.01). Several degrees of deviation and deformation of both the ventricular system and brain parenchyma were detected by MRI. Subjective MRI findings were not associated with intracranial hypertension. In conclusion, this study shows that in sheep affected by slow-growing lesions, severe alterations in the neuroscore and the results of objective MRI are related to an increased intracranial pressure beyond the normal threshold.

Apoptosis of mouse hippocampal cells induced by Taenia crassiceps metacestode factor.

Seizures, headache, depression and neurological deficits are the signs and symptoms most frequently reported in human neurocysticercosis. However, the cause of the associated learning and memory deficits is unknown. Here, we used Taenia crassiceps infection in mice as a model of human cysticercosis. The effects of T. crassiceps metacestode infection or T. crassiceps metacestode factor (MF) treatment on mouse hippocampal cells were studied; control mice were included. At 45 days after infection or treatment of the mice with MF, all mice were anaesthetized and perfused transcardially with saline followed by phosphate-buffered 10% formalin. Then the brains were carefully removed. Coronal sections stained using several techniques were analysed. Extensive and significant apoptosis was found in the experimental animals, mainly in the dentate gyrus, CA1, CA2, CA3 and neighbouring regions, in comparison with the apparently intact cells from control mice (P < 0.01). These results suggest that neurological deficits, especially the learning and memory deficits, may be generated by extensive apoptosis of hippocampal cells.

A Taenia crassiceps metacestode factor enhances ovarian follicle atresia and oocyte degeneration in female mice.

The histopathological effects of Taenia crassiceps infection or T. crassiceps metacestode factor inoculation on the mouse ovary were determined using six female mice in three groups: infected mice, mice inoculated with the metacestode factor and control mice. The control group was subcutaneously inoculated with healthy peritoneal fluid. The infected group was intraperitoneally inoculated with 40 T. crassiceps metacestodes, and the metacestode factor group was subcutaneously inoculated with T. crassiceps metacestode factor (MF). Light and electron microscopy and TUNEL (terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labelling) assays revealed a significant increase in ovarian follicular atresia (predominantly in antral/preovulatory stages of development), oocyte degeneration (P< 0.05), and a decrease in the amount of corpus luteum in follicles of mice infected and inoculated with MF compared with the control group. Significant abnormalities of the granulosa cells and oocytes of the primordial, primary and secondary ovarian follicles occurred in both treated mouse groups (P< 0.05) compared with no degeneration in the control group. These pathological changes in female mice either infected with T. crassiceps metacestodes or inoculated with T. crassiceps MF may have consequences for ovulation and fertility.

[The influence of Taenia taeniaeformis larval infection on morphometrical parameters of muskrat (Ondatra zibethicus)]. / Wplyw zarazenia larwami tasiemca Taenia taeniaeformis na parametry morfometryczne pizmaków (Ondatra zibethicus).

An investigation aimed to check the influence of Taenia taeniaeformis larvae on morphometrical parameters of muskrat (Ondatra zibethicus) was carried. A total of 30 animals were hunted down in upper Vistula river basin in south Poland, then measured, weighed and dissected. Statistical comparison were done using U Mann-Whitney test. T. taeniaeformis larvae--cysticercus fasciolaris was found in the liver of 24 muskrats (80%). Significant differences between infected and non infected animals are reported, as regards their body mass, total length, abdomen circumference (p < 0.01) and also in body length (total minus tail length), head length, or chest and neck circumference (p < 0.05). The effect of infection on both muskrat condition and the presence of adult cestodes in definitive hosts are discussed.

Human taeniasis in western Romania and its relationship to multicultural food habits and influences.

OBJECTIVES: Taeniasis, an intestinal infection produced by adult tapeworms of the genus Taenia, is acquired by the consumption of raw or undercooked beef or pork containing the infective cysticerci. The symptoms are generally mild and include abdominal pain, nausea, dizziness, headache, weight loss, anorexia, and allergic syndromes. In Romania, the morbidity of taeniasis ranges between 0.4% and 0.75% with higher rates in Moldavia and Banat regions as a consequence of regional gastronomic customs. This study aimed to overview the epidemiological, clinical, and therapeutic characteristics of taeniasis cases diagnosed in Timis County, part of Banat region, during a 37-year period (1971-2007). PATIENTS AND METHODS: The authors have retrospectively analyzed the medical charts of 26 adult patients (mean age 38.3 years) admitted to the reference hospital for infectious diseases in southwestern Romania. RESULTS: Females (77.0%, n = 20), inhabitants of urban areas (65.4%, n = 17), and laborers (46.2%, n = 12) were the most affected categories. The clinical symptoms included abdominal pain (57.7%, n = 15), asthenia (26.9%, n = 7), and loss of appetite (15.4%, n = 4). Eosinophilia was evidenced in 38.5% (n = 10) of the cases. For 80.8% (n = 21) of the patients, the hospitalization period ranged from 1 to 7 days. Niclosamide was administered in 61.5% (n = 16) of the cases. CONCLUSIONS: The disease might be more frequently diagnosed in patients with mild symptomatology or asymptomatic ones who usually consult general practitioners and hence the low number of cases treated in hospitals. As a consequence, specific prophylactic measures oriented mainly to sanitary education of the masses must be considered for its eradication. Collaboration between family physicians and veterinary doctors must be strengthened especially in the countryside regions where humans live in close proximity to animals on which they rely mostly for their food resources.

Neuroimmunoendocrine modulation in the host by helminth parasites: a novel form of host-parasite coevolution?

Helminth parasites have evolved diverse molecular mechanisms that facilitate their establishment, growth and reproduction inside an immunologically hostile environment. Thus, the physiological interactions during the course of the immune response to helminths are complex. Infection induces antigen-specific recognition by the immune system, which is consequently charged with the responsibility of marshalling the appropriate effector responses necessary to destroy the parasite, or at the very least inhibit its progression. Obviously, the immune system should accomplish this task while minimizing collateral damage to the host. As our understanding of the neuroendocrine system grows, it has become increasingly clear that this complex network of neurotransmitters, hormones, and cytokines plays an important role in mediating immunity. Helminths present an especially complex relationship between pathogen and these physiological systems, with hormonally dependent host factors such as sex and age correlated with parasite success. On top of the effect that this particular type of parasites may have on the invaded host, recent experimental evidence suggests that helminth parasites not only actively evade immune response, but are also able to exploit the hormonal microenvironment within their host to favor their establishment, growth and reproduction. This complex strategy of host-parasite relationship is much better exemplified by two helminth parasites: the trematode Schistosoma mansoni and the cestode Taenia crassiceps that respond to adrenal steroids and sexual steroids, respectively. Understanding how the host endocrine system can under certain circumstances favor the establishment of a parasitic infection opens interesting perspectives into the host-parasite relationship field.

Substance P is associated with heart enlargement and apoptosis in murine dilated cardiomyopathy induced by Taenia crassiceps infection.

Dilated cardiomyopathy (degeneration of heart muscle and heart enlargement) is an important cause of heart failure among young adults. Dilated cardiomyopathy may be a complication during or after various viral, bacterial, or parasitic diseases. Substance P (SP) is a neurotransmitter that is involved in the pathogenesis of various diseases. To determine whether SP is associated with cardiac changes in murine cysticercosis, we compared heart-weight to body-weight ratio, cardiac pathology, cardiomyocyte size, and cardiac-apoptosis (TUNEL assay) in hearts from Taenia crassiceps-infected (wild-type vs. SP-knockout) mice. We noted that, as compared with control uninfected wild-type mice, elevated protein levels of SP and its receptor as studied by ELISA or immunohistochemistry, respectively, were elevated in the hearts of parasite-infected wild-type mice. The heart-weight to body-weight ratios were significantly higher in the parasite-infected wild-type mice versus those of the infected SP-knockout mice. Furthermore, wild-type infected mice developed dilated cardiomyopathy with increased chamber size of both ventricles, decreased ventricular wall thickness, compensatory cardiomyocyte hypertrophy, and increased cardiac apoptosis. This cardiac pathology did not develop in mice lacking SP activity (i.e., in infected SP knockout mice) or in uninfected mice. These data indicate that SP is associated with cardiac changes in an animal model of parasitic dilated cardiomyopathy.

Histomorphological study of the preputial and clitoral glands in BALB/c mice with experimental Taenia crassiceps infections.

Male preputial and female clitoral glands of mice undergo development that depends on the level of hormones in the animal. Experimental infection with Taenia crassiceps cysticerci results in significant physiological modifications in the host. Here, we investigated the histomorphological alterations induced by the parasite in these pheromonal glands. Preputial and clitoral glands were recovered from mice at 15, 35, 50, and 70 days postinfection (DPI). The glands were examined macroscopically and microscopically after histological preparation. Male preputial glands show a marked atrophy 35 days after infection. This atrophy is the result of a disorganization of the acinus tissue structure. During the course of infection, the basal, intermediate, and mature acinar cell layers are reduced, and finally, at 70 DPI, the gland includes only the duct system and fibrotic structures. In contrast, females are not affected by the infection because no modifications were observed in the morphology or histology of the clitoral glands. A probable cause for such a divergence between infected male and female mice might be related to a sex steroid imbalance as described during T. crassiceps infection.

Laboratory animal models for human Taenia solium.

Human beings are the only hosts of adult Taenia solium; thus, many aspects of the host-parasite relationship are unknown. The development of successful experimental models of taeniasis allows in-depth investigations of the host-parasite relationship. We established experimental models in hamsters, gerbils and chinchillas. Here we review our findings regarding the characteristics of the tapeworms, their anchoring site and development, as well as the humoral and cellular immune response they elicit. We also used statistics to analyze the data obtained in different infections performed along several years. Furthermore, we compared the size of T. solium rostellum and strobila recovered from hamsters and gerbils to those obtained from humans. Our data indicate that these rodents are adequate experimental models for studying T. solium in its adult stage; that parasites induce immune responses and that hamsters seem to be more permissive hosts than gerbils, since parasites survive for longer times, grow longer and develop more, and the inflammatory response in the intestinal mucosa against T. solium is moderate. Finally, chinchillas are the most successful experimental definitive model for adult T. solium, since tapeworms with gravid proglottids are obtained, and the life cycle can be continued to the intermediate host.

Epileptogenic activity of granulomas associated with murine cysticercosis.

Neurocysticercosis, caused by Taenia solium, is a common cause of neurologic disease in developing countries and among immigrants to the United States. Seizures are the most common clinical manifestation of neurocysticercosis. Imaging studies of patients with seizures from neurocysticercosis typically reveal evidence of an inflammatory reaction associated with the parasite or calcified granulomas. This study investigated whether a substance produced by the host granulomatous reaction to the dying parasite, in a mouse model of the infection, is sufficient to induce epileptiform activity. Granulomas associated with Taenia crassiceps cysticerci were removed from the peritoneal cavity of infected mice. One piece of the granuloma was used for blinded histological staging of the dying parasite. The second piece was used to generate extracts, which were injected into the hippocampus of an anesthetized Sprague-Dawley rat. Positive controls included animals injected with kainic acid, picrotoxin, or bicuculline. Seizures were recorded after injection of extracts from 6 out of 6 early stage granulomas, but only 1 out of 9 late stage granulomas. Injections of buffered saline, extracts from non-stimulated mouse spleen cells, and homogenates of viable parasite material caused no epileptiform activity. The data suggest that a substance in the granulomas early in the inflammatory response to the dying parasite is capable of inducing seizure activity. Further experiments are needed to dissect out the exact seizure mediator in the granuloma extracts.

Prevalence of Taenia multiceps in sheep in northern Jordan.

From March 1996 to February 1997, slaughtered-sheeps' heads were examined for the metacestode of Taenia multiceps. Out of 451 sheep heads, only 12 (3%) were infested. All cysts but one were in the age group 0.5-2.5 years old, with prevalence of 10% (11 of 108). Eleven of 12 infested heads were found during the spring and autumn seasons. Out of 95 flocks involved in questionnaire survey unrelated to the abattoir survey, all the farmers reported the existence of the clinical signs known for coenurosis and described it in locally known names and diseases. Twenty-five of them had recent cases that were diagnosed by the veterinarian as coenurosis cases. Each flock reported one or two cases at the time of survey. A variety of clinical signs were reported from these cases (n = 42). These included circling (86%), head pressing (52%), blindness (29%) and paresis (40%). Coenurosis is a sheep-health problem and an important cause of sheep culling in Jordan.

Parasitose intestinal: profilaxia e tratamento dessa esquecida realidade brasileira / Intestinal parasite: prophylaxis and treatment of that forgotten brazilian reality

Com o evoluir da Medicina, inúmeras técnicas, métodos de diagnóstico e tratamento foram surgindo para as novas doenças constantemente descobertas. E, nessa realidade, com freqüência deparamo-nos com médicos capazes de tratar doenças complexas, com tecnologias modernas. Porém muitos se esquecem de considerar doenças básicas da comunidade, como é o caso das parasitoses intestinais, uma realidade brasileira que, embora prevalecente nas camadas socioeconomicamente menos favorecidas, afeta todos os níveis sociais. A finalidade deste artigo é promover uma revisão bibliográfica sobre o tema e abordar as principais parasitoses, dando subsídio ao diagnóstico, e, principalmente, frisar a conscientização da necessidade das medidas preventivas

Inhibitory effect of different UV lamps on the infectivity of taeniid eggs.

The expanding distribution of alveolar echinococcosis in Hokkaido, Japan necessitates a search for control measures, particularly for killing Echinococcus eggs; and UV radiation is a potential tool. To determine the effective UV lamp and its optimum duration of exposure to inhibit the infectivity of taeniid eggs, three UV lamps (UVA, UVB and UVC) with peak emissions at different wavelengths were used to irradiate eggs of Taenia taeniaeformis. Irradiation was done in durations of 30, 90, 270, 810, 2,430 and 7,290 s. Infectivity of the irradiated eggs was tested by oral inoculation into rats. The inhibitory effect of the UV lamps at different exposure durations was determined by the reduction in the larval cyst establishment and by the delay of larval development. The UVC lamp (narrow peak at 254 nm) was found to be the most effective lamp at an exposure duration of more than 2,430 s (2,430 mJ/cm2), attaining 100% reduction. Also, shorter exposure durations produced a significant effect on the development of irradiated eggs in a greater percentage of small cysts (> 1 mm) among the metacestodes. Irradiation delayed the development of some cysts, as observed in histopathological sections. UVA and UVB lamps were not able to attain 100% reduction. It is concluded that the UVC lamp can be used as a tool in sterilizing taeniid eggs and is thus a promising method to control echinococcosis, although it may require a higher intensity of exposure.

Parenchymal neurocysticercosis: follow-up and staging by MRI.

We describe the evolution of parenchymal cerebral cysticerci on MRI, to assess signs of early cyst degeneration. We studied 15 lesions in four treated and one untreated patient. MRI was performed before therapy and repeated in the 1st month after each course of anticysticercus drugs, every 4 months during the 1st year and then annually; the follow-up period was 8-48 months. Lesions were classified according to changes in four features: cyst content and capsule signal, gadolinium enhancement and oedema signal. We were able to recognise each of the pathological phases; five MRI stages were identified. Stage 1 showed oedema and/or nodular gadolinium enhancement in the tissue invasion phase; stage 2 was cerebrospinal fluid-like signal within a cyst in the vesicular phase; stage 3 showed a thick capsule with an impure liquid content signal and surrounding oedema, in the cystic phase; stage 4 showed the disappearance of the cyst fluid content signal in the degenerative phase; stage 5 showed a calcified lesion in the residual phase. Stage 1 lesions disappeared after therapy; the other progressed from one stage to another. Stage 4 indicated the end of viability of the parasite and determined the point after which treatment was useless. On T2-weighted images changes in the cyst content differed according to the history of the lesion; nodular low intensity followed the natural degeneration of the parasite and a mixed fluid signal with punctate low signal seemed to represent the specific result of therapy. MRI staging can help in the evaluation of indications for treatment and facilitate clinical therapeutic trials.