Miniature pigs as the intermediate host for Taenia asiatica.

Taenia asiatica, utilizing pigs as an intermediate host, degenerates and/or calcifies within a few months after infection in pigs, whereas Taenia solium, also using pigs as an intermediate host, can develop into a mature metacestode within a couple of months and can survive for prolong periods in pigs. This raises the question of whether pigs are suitable intermediate hosts for T. asiatica. The host-parasite relationships between T. asiatica and pig strains, such as infection rates and development of metacestodes, have been reported in previous studies: however, little is known about the pathological changes that occur in T. asiatica metacestodes in pigs. Therefore, in the present study, the pathological changes in T. asiatica within 30 days of infection were observed using CLAWN miniature pigs as model animals. Metacestodes were observed on the diaphragmatic surface and throughout the parenchyma of the pig liver 9 days after infection; however, these metacestodes were surrounded by eosinophilic abscesses, and some had already begun to degenerate. By day 20 and 30 post-infection, metacestodes were surrounded by eosinophilic abscesses and had completely degenerated without forming a scolex. These results indicate that although T. asiatica infected miniature pigs, the metacestodes degenerated owing to strong immune responses from the pigs. Therefore, the CLAWN miniature pig are not a suitable intermediate host for T. asiatica. The possible reasons why T. asiatica metacestodes were degenerated and the potential roles of pigs in transmitting the parasite to humans in T. asiatica-endemic regions are discussed in this study. Additionally, data debating whether pigs are suitable intermediate hosts for T. asiatica are provided.

Receptor Tyrosine Kinase Signaling Involves Echinococcus-Host Intercommunication: A Potential Therapeutic Target in Hepatic Echinococcosis.

Echinococcosis, one of the most serious and life-threatening parasitic forms of zoonosis worldwide, is caused by the larvae of Echinococcus granulosus (E. granulosus) and Echinococcus multilocularis (E. multilocularis). Various drugs are being applied clinically to treat zoonosis; however, their therapeutic efficacy remains a great challenge, especially with albendazole as the preferred drug of choice. Receptor tyrosine kinase (RTK) signaling controls normal cellular proliferation, differentiation, and metabolism in humans and mammals, which are intermediate hosts of E. granulosus and E. multilocularis. Disruption of RTK signaling can cause various forms of carcinogenesis and exacerbate the progression of certain forms of parasitic disease. As a result, a significant number of studies on tyrosine kinase inhibitors (TKIs) have been conducted for the treatment of cancer and parasitic infection, with some TKIs already approved for clinical use for cancer. Notably, RTK signaling has been identified in the parasites E. granulosus and E. multilocularis; however, the mechanisms of RTK signaling response in Echinococcus-host intercommunication are not fully understood. Thus, understanding the RTK signaling response in Echinococcus-host intercommunication and the potential effect of RTK signaling is crucial for identifying new drug targets for echinococcosis. The present review illustrates that RTK signaling in the host is over-activated following infection by E. granulosus or E. multilocularis and can further facilitate the development of metacestodes in vitro. In addition, some TKIs exert strong parasitostatic effects on E. granulosus or E. multilocularis, both in vitro and/or in vivo, through downregulation of RTK signaling molecules. The summarized findings suggest that RTK signaling may be a promising drug target and that TKIs could be potential anti-Echinococcus drugs warranting further research.

Investigation on Descriptive Epidemiology, Geographical Distribution, and Genotyping of Echinococcus granulosus s.l. in Bovine from Romania.

Bovine echinococcosis is a zoonotic disease with worldwide distribution, causing significant economic losses in the affected animals and important public health concerns. The aim of the current study was to investigate the presence and geographical distribution of cystic echinococcosis, and molecular characterization of Echinococcus granulosus s.l. from slaughtered cattle in Romania. In the period 2020−2021, a total of 2693 cattle (aged 2−21 years) slaughtered from the breeds Bruna de Maramureș, Balțata Româneasca, and a mixed breed were examined to identify hydatid cysts. Cysts were identified in 66 cattle (2.45%). The predominant location of hydatid cysts was the lungs. Most cysts were non-fertile. By age categories, hydatidosis was reported in the age categories 2−12 years (6/2341; 0.25%), 13−16 years (11/244; 4.5%), 17−20 years (41/85; 48.23%), and over 21 years (8/23; 34.78%). Following the PCR analysis of 10 samples from the lungs (protoscoleces/proliferative membrane/hydatid liquid), DNA fragments were identified in 5 samples. Following sequencing, the identified species was Echinococcus granulosus sensu stricto (s.s.). The study results indicate that the disease is still present in several of the investigated regions of Romania, highlighting a potential public health risk.

Echinococcus granulosus sensu lato in animal intermediate hosts: What is with the organ location?

Organ or tissue tropism/preference in many parasites is essential for their establishment, survival and pathogenesis. In protozoan parasites e.g. Trypanosoma and Plasmodium, tissue tropism is associated with many important aspects such as transmission, treatment, and pathogenesis. In these parasites, tissue tropism is achieved by mechanisms such as sequestration, extravasation, transcellular migration, and vascular permeability. In contrast, little is known about the mechanism behind organ tropism/preference and the potential implication in parasitic metazoans like Echinococcus. Since intraspecies/genetic variation was described for Echinococcus, the organ preference of currently known species and subspecies among animal intermediate hosts remains unclear or perhaps poorly investigated. Here, analysis of 89,359 Echinococcus cysts from different animal intermediate hosts across 47 countries suggests a potential organ distribution pattern in different animal intermediate hosts. For example, E. granulosus s.s. (G1, G3) and E. canadensis (G7) were found more in the liver of sheep and pigs, respectively than in other organs, whereas E. ortleppi and E. canadensis G6 were significantly higher in the lung of cattle and camels, respectively. While the mechanism of organ tropism in Echinococcus and whether it is species/genotype-dependent, host-dependent, or a combination of both is still a subject of future investigations, further and detailed investigation could provide significant information that may be applicable in the diagnosis and treatment of organ-specific cystic echinococcosis or designing host or genotype-specific interventions.

A novel intermediate host for Taenia serialis (Gervais, 1847): The European roe deer (Capreolus capreolus L. 1758) from the Monti Sibillini National Park (MSNP), Italy.

Taeniids are multi-host parasites with an indirect life cycle that strictly depends on a predator-prey relationship. Parasites with a complex life cycle may exhibit different degrees of host-specificity at each life stage. Knowing the host breadth is a fundamental concept of the biology and epidemiology of these multi-host parasites. Morphological identification of tapeworms is challenging and occasionally may produce misdiagnosis. Thus, molecular investigations were carried out for the identification of parasitic cysts detected from muscle tissues in a male roe deer necropsied at the Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche "Togo Rosati" (Central Italy). Sanger sequencing showed 99% query cover, 2e-109 e-value, and 100% identity with Taenia serialis. The exact definitive host was not revealed in this report, but red foxes and Italian wolves may play a significant role as being widespread within the area. Wildlife surveillance is crucial to monitor for human and animal health since global distribution and flexibility in intermediate hosts of many and even more critical taeniids species may enlarge their host range.

New geographic records for Echinococcus canadensis in coyotes and moose from Nova Scotia, Canada.

Echinococcus spp. tapeworms can cause serious diseases in mammals, including humans. Within the E. granulosus species complex, metacestodes produce unilocular cysts that are responsible for cystic echinococcosis in animal intermediate hosts. Canids are definitive hosts, harbouring adult cestodes in their intestines. Adult E. canadensis were recovered from the small intestine of 1 of 262 coyotes (Canis latrans) from Nova Scotia, Canada. Subsequently, we found unilocular cysts in lungs and livers of 4 of 8 sympatric moose (Alces alces) from Cape Breton Island. DNA was extracted from three cysts using the Qiagen DNeasy Blood and Tissue kit and assayed by polymerase chain reaction (PCR) with primers (cest4 and cest5) for a 117-bp region of the small subunit of ribosomal RNA of E. granulosus sensu lato, and further validated as E. canadensis G8 using primers targeting nicotinamide adenosine dinucleotide dehydrogenase subunit 1 (ND1) and cytochrome c oxidase subunit 1 (CO1) mitochondrial genes. These are the first records of E. canadensis in any of the three Maritime provinces, which include Nova Scotia, New Brunswick, and Prince Edward Island. The parasite was thought to be absent in this region due to extirpation of wolves (Canis spp.) in the 1800s. These findings suggest that further wildlife surveillance and risk assessment is warranted.

Tapeworms as pathogens of fish: A review.

Tapeworms (Cestoda) represents a species rich (about 5000 species) group of flatworms (Neodermata) parasitizing all groups of vertebrates including humans, with about 1000 species parasitizing elasmobranchs and almost 500 occurring in teleosts as adults. They are common parasites of cultured fish, both as adults and larvae (metacestodes), but only few adult tapeworms are actually pathogenic for their fish hosts. In contrast, cestode larvae can be harmful for fish, especially plerocercoids migrating throughout their tissue and internal organs. Current knowledge of host-parasite relationships, including immune response of fish infected with tapeworms, is still insufficient to enable adequate control of cestodoses, and most data available were obtained several decades ago. Treatment of fish infected with adult tapeworms is effective, especially with praziquantel, whereas the treatment of metacestodes is problematic. Control measures include interruption of the complex life cycle and prevention of transport of uninspected fish to new region.

In vivo and in vitro efficacy of crocin against Echinococcus multilocularis.

BACKGROUND: Alveolar echinococcosis (AE) is a fatal zoonosis caused by the larvae of Echinococcus multilocularis. However, current chemotherapy treatment options are based on benzimidazoles [albendazole (ABZ) and mebendazole], which have limited efficacy. Therefore, novel drugs are necessary for the treatment of this disease. METHODS: The anthelmintic effects of crocin were tested on E. multilocularis metacestodes, germinal cells and protoscoleces in vitro. Human foreskin fibroblasts (HFFs) and Reuber rat hepatoma (RH) cells were used to assess cytotoxicity. The in vivo efficacy of crocin was investigated in mice following secondary infection with E. multilocularis. Furthermore, collagen deposition and degradation in host tissues around the metacestodes were evaluated. RESULTS: In vitro, crocin had a median effective concentration of 11.36 µM against cultured E. multilocularis metacestodes, while it reduced germinal cell viability at a median inhibitory concentration of 10.05 µM. Crocin was less toxic to HFFs and RH mammalian cell lines than to metacestodes. Transmission electron microscopy revealed that crocin treatment resulted in structural damage in the germinal layer. In addition, 60.33 ± 3.06% of protoscoleces were killed by treatment with 10 µM crocin for 7 days, indicating that crocin has a parasiticidal effect. In vivo, the metacestode weight was significantly reduced after the administration of crocin at 50 mg/kg and 100 mg/kg (55.1 and 68.1%, respectively). Metacestode pathology showed structural disruption of the germinal and laminated layers after crocin treatment. The crocin- and ABZ-treated groups presented significant increases in the levels of interleukin (IL)-2 and IL-4. Furthermore, crocin inhibited the expression of matrix metalloproteinases (MMPs) (MMP2 and MMP9) and promoted collagen deposition in the metacestode. CONCLUSIONS: Crocin was demonstrated to exert parasiticidal activity against E. multilocularis in vitro and in vivo, and can be developed as a novel drug for the treatment of AE.

Massive infection of a song thrush by Mesocestoides sp. (Cestoda) tetrathyridia that genetically match acephalic metacestodes causing lethal peritoneal larval cestodiasis in domesticated mammals.

BACKGROUND: Peritoneal larval cestodiasis induced by Mesocestoides Vaillant, 1863 (Cyclophyllidea: Mesocestoididae) is a common cause of severe infections in domestic dogs and cats, reported also from other mammals and less frequently from birds. However, there is a limited knowledge on the taxonomy of causative agents of this disease. RESULTS: In the present study, we investigated a massive, likely lethal, infection of a song thrush Turdus philomelos (Passeriformes: Turdidae) by Mesocestoides sp. tetrathyridia. We performed combined morphological and phylogenetic analysis of the tetrathyridia and compared them with the materials obtained previously from other birds and mammals. The metrical data fitted within the wide range reported by previous authors but confirmed the limited value of morphological data for species identification of tetrathyridia of Mesocestoides spp. The molecular analyses suggested that the isolates represented an unidentified Mesocestoides sp. that was previously repeatedly isolated and sequenced in larval and adult forms from domestic dogs and cats in Europe, the Middle East and North Africa. In contrast to the present study, which found encysted tetrathyridia, four of the five previous studies that identified the same species described infections by acephalic metacestodes only. CONCLUSIONS: The tetrathyridia of the examined Mesocestoides sp. are described in the present study for the first time. However, the possible match with the species that were previously reported to infect birds remains uncertain. The phylogenetic analyses also suggested the rejection of two cases that were previously identified as Mesocestoides corti as they were likely caused by the same species as in the presently reported infection case. The newly provided DNA sequences should allow the assignment to species in the future, when adults of the genus Mesocestoides are more thoroughly sequenced.

Identification and characterization of microRNAs in a cestode Hydatigera taeniaeformis using deep sequencing approach.

Hydatigera taeniaeformis (formerly known as Taenia taeniaeformis) is a parasitic tapeworm that has a worldwide distribution. H. taeniaeformis is naturally transmitted between mice and cats and threatens to human health, especially those who are in close contact with pets. MicroRNAs (miRNAs) are a class of small regulatory non-coding RNAs involved in the regulation of parasite growth and development, parasite infection and immunology, and host-pathogen interactions. The miRNA profile of H. taeniaeformis remains to be elucidated. Herein, 47 conserved miRNAs (grouped into 34 miRNA families) and 4 novel miRNAs were identified in H. taeniaeformis metacestodes using deep sequencing approach. Among them, hta-miR-71, -let-7, and-miR-87 was absolutely predominant in H. taeniaeformis metacestodes. Moreover, comparative analysis revealed the presence of miR-71/2 and miR-4989/277 clusters in H. taeniaeformis. Nucleotide bias analysis of identified miRNAs showed that the adenine (A) was the dominant nucleotide at the beginning of the miRNAs, particularly at the positions of third and 7th nucleotides. The study provides rich data for further understandings of H. taeniaeformis biology.

High frequency of Taenia pisiformis metacestodes and high sex-associated susceptibility to cysticercosis in naturally infected wild rabbits.

Sexual dimorphism is a well-documented phenomenon observed at all levels of the animal kingdom, with the inclusion of both sexes in clinical trials and basic research becoming mandatory. Regarding parasitosis, in several animal species, the signs and virulence of the disease may change depending on the sex of the affected animal. In the cestodiasis caused by Taenia solium and Taenia crassiceps, females are more susceptible to experimental infection than males. Cysticercosis by Taenia pisiformis in rabbits has acquired relevance due to its economic impact, namely affecting welfare and production. In America, specifically in Mexico, there are no formal reports on the infection with T. pisiformis metacestodes in populations of wild rabbits, despite being the country with more endemic species (about 15 species), among them, the volcanoes rabbits or the endangered teporingo (Romerolagus diazi). In this study, 31 wild rabbits were obtained by hunters of some regions of Morelos state during several hunting seasons, and sex, physiological stage, and number of metacestodes were recorded. A high frequency of infection by T. pisiformis metacestodes (67.7%) was found. Also, a higher susceptibility to this infection was observed in does (80% infected) compared to bucks (40%), finding 84.2% of metacestodes (235 metacestodes) in does and 15.8% of metacestodes (44 metacestodes) in bucks. The percentage of infection was higher in lactating compared with pregnant and non-pregnant does, with metacestodes lodging mainly in the uterus. Increasing our knowledge regarding parasitic infections can help us better understand transmission circles as well as the parasite-host interaction of these increasingly at risk rabbit species.

Efficacy of ursolic acid against Echinococcus granulosus in vitro and in a murine infection model.

BACKGROUND: Cystic echinococcosis is a global public health problem; however, the drugs (albendazole and mebendazole) currently recommended by WHO for its treatment, have limited efficacy. Therefore, novel drugs are required to provide more choices for the treatment of this disease. METHODS: The anthelmintic effects of ursolic acid (UA) were tested on Echinococcus granulosus protoscoleces, germinal cells and metacestodes in vitro. The in vivo efficacy of UA was investigated in mice following secondary infection with E. granulosus. Furthermore, the corresponding ultrastructural damage induced by UA was evaluated by electron microscopy. RESULTS: In vitro, 45.95 ± 5.30% of protoscoleces were killed by UA at 40 µg/ml, while the growth of more than 90% of germinal cells was inhibited by UA at 10 to 40 µg/ml. The same effect was observed in metacestodes 7 days after treatment with UA at 10, 20 and 40 µg/ml, and more than 50% of metacestodes showed loss of integrity at the end of the experiment. In vivo, metacestode weight was significantly reduced following oral administration of UA at 200 and 100 mg/kg (39.5 and 38.3%, respectively). Additionally, ultrastructural damage, such as alternations in germinal cell morphology and formation of vacuoles and lipid granules were observed in parasites treated with UA in vitro, while detachment of the germinal layer from the laminated layer was also seen in metacestodes in vivo. CONCLUSIONS: UA was demonstrated to exert parasiticidal activity against E. granulosus in vitro and in vivo, thus implicating UA as a potential anti-echinococcosis agent.

MicroRNA expression profile in RAW264·7 macrophage cells exposed to Echinococcus multilocularis metacestodes.

MicroRNAs (miRNAs) are short noncoding RNAs, involved in the regulation of parasite diseases. However, a role of miRNAs in Echinococcus multilocularis infection remains largely unknown. In this study, we first found the expression levels of key genes involved in miRNA biogenesis and function, including Ago2, Xpo5, Tarbp2 and DgcR8, were obviously altered in the macrophage RAW264·7 cells exposed to E. multilocularis metacestodes. Compared with the control, 18 and 32 known miRNAs were found to be differentially expressed (P 2) in the macrophages exposed to E. multilocularis metacestodes for 6 and 12 h, respectively. Among these, several are known to be involved in regulating cytokine activities and immune responses. Quantitative real-time polymerase chain reaction results showed that the expression of nine selected miRNAs was consistent with the sequencing data at each treatment time points. Moreover, there were statistically significant correlations between the expression levels of miRNAs and their corresponding targeted genes. Our data give us some clues to pinpoint a role of miRNAs in the course of infection and immunity of E. multilocularis.

In Vitro Effects of Amino Alcohols on Echinococcus granulosus.

Cystic echinococcosis is a globally distributed zoonotic disease, which is caused by the larval stage of Echinococcosus granulosus sensu lato. The chemotherapy of the disease is limited to the use of benzimidazoles. Recently, mefloquine and its analogues, aminoalcohol-carbazole, and some amino alcohol derivatives were reported to display inhibitory effects on parasites. Here, the activities of 130 amino alcohol compounds against E. granulosus were tested on protoscoleces and germinal cells at a concentration of 20 µg/ml over a period of three days. As a result, sixteen compounds totally were effective against both protoscoleces and germinal cells, and their IC50 and LC50 were also calculated respectively. Then effects of the most active compounds were observed on metacestodes over 14 days in vitro. Although the structure of active compounds were variable, hydroxyl and amino groups connected by two carbon atoms are held in common as the key feature of these compounds. The further investigation on metacestodes incubated with these active compounds revealed that the effects of JF16 and BTB4 were comparable to that of mefloquine and mebendazole. In addition, the ultrastructure alternations induced by these compounds on E. granulosus were confirmed by scanning electron microscopy and transmission electron microscopy observations. In conclusion, amino alcohols were a class of compounds with efficacy against E. granulosus. The most effective compounds JF16 and BTB4 indicated that their basic structure would be useful in the synthesis of new compound for the treatment of echinococcosis. However, their in vivo efficacy and toxicity need to be carefully evaluated in the future.

Systematic review and meta-analysis of metacestodes prevalence in small ruminants in Ethiopia.

Metacestodes, the larval stages of canid cestode parasites, are among the causes of morbidity, mortality and financial losses in small ruminants in Ethiopia as a result of organ and carcass condemnation at slaughter. Several studies have been conducted over the years; however, these studies often had limited scope and coverage. This systematic review and meta-analysis was conducted to collate the information so far available in order to provide a pooled prevalence estimate at national level and identify potential predictors. Published and grey literature written in English and Amharic in the period from, 1st of January 1990 to June 25, 2015 were searched from electronic databases and repositories of academic and research institutions. Relevant animal level data on 67,743 small ruminants was extracted from 23 published articles and one master's thesis resulting altogether in 86 animal level reports that conformed to predefined criteria. The dataset was analyzed using a meta-analytical approach. The pooled prevalence estimate computed for metacestodes infection was 11.8% with a 95% confidence interval (CI) of 9.1, 15.4. The highest prevalence estimate 31.2% (95% CI: 23.1, 40.9) was found for Cysticercus tenuicollis (Taenia hydatigena) followed by cystic echinococcosis (Echinococcus granulosus) 8.8% (95% CI: 5.8, 13.1), Cysticercus ovis (Taenia ovis) 4.9% (95% CI: 2.9, 9.4) and Coenurus cerebralis (Taenia multiceps) 4.6% (95% CI: 1.6, 12.2). Among the predictors considered for heterogeneity analysis only sample size and metacestode type fitted the final multivariable meta-regression model and explained 26.3% of the explainable heterogeneity between studies (p<0.05). The prevalence was noted to decrease with increasing sample size. No significant difference in prevalence was observed between sheep and goats (p>0.05). In conclusion, this review showed a widespread occurrence of metacestodes in small ruminants in Ethiopia. Thus, a holistic approach to break the life cycle of these parasitic stages is suggested, including regulatory interventions that encourage dog owners to keep their dogs confined and prevent backyard slaughter and proper management of abattoir waste disposal.

Efficacy of albendazole in combination with thymol against Echinococcus multilocularis protoscoleces and metacestodes.

The larval (metacestode) stage of the tapeworm Echinococcus multilocularis causes alveolar echinococcosis (AE), a mainly hepatic disease characterized by continuous asexual proliferation of metacestodes by exogenous budding, resulting in the tumor-like, infiltrative growth of the parasite lesion. Current chemotherapeutical treatment of AE relies on the use of benzimidazoles, albendazole (ABZ) and mebendazole, but these drugs act parasitostatic rather than parasitocidal, and due to their low success rate they imply a lifelong application causing severe side effects. Thymol is one of the major components of the essential oils of Thymus and is a widely known anti-microbial agent. The aim of the present work was to compare the efficacy of albendazole (ABZ) and thymol separately or combined on E. multilocularis protoscoleces and metacestodes. For this purpose, microscopical examinations at different time points were carried out. Moreover the tegumentary enzyme gamma glutamyl transferase (GGT) was measured to quantify the damage in metacestodes. Even though treatments of in vitro cultured E. multilocularis protoscoleces or metacestodes with ABZ or/and thymol showed that the drugs have an adverse effect on parasite viability, the combination of the two compounds at the concentration of 10µg/ml showed the maximum anti-parasitic effect. Three days postincubation the first effects of the treatment were detected on protoscoleces and a marked reduction in viability (33%) was registered at day 18. Incubation of E. multilocularis metacestodes in the presence of ABZ 10µg/ml+thymol 10µg/ml during 10 days resulted in dramatic alterations such as strongly irregular and fissured surface and markedly disrupted vesicles. Scanning electron microscopy showed that protoscoleces as well as the germinal layer of E. multilocularis metacestodes were dramatically damaged following ABZ or/and thymol treatment. Also an important increase of tegumentary enzyme GGT was registered after 72h postincubation with both drugs. The data reported in this article demonstrate a clear in vitro effect of ABZ+thymol against E. multilocularis protoscoleces and metacestodes.

Histopathologic aspects in Plagioscion squamosissimus (HECKEL, 1940) induced by Neoechinorhynchus veropesoi, metacestodes and anisakidae juveniles / Aspectos histopatólogicos em Plagioscion squamosissimus induzidos por Neoechinorhynchus veropesoi, metacestódeos e juvenis da Família Anisakidae

Plagioscion squamosissimus (Heckel 1840), a fish endemic to the Amazon Basin and commonly known as the “silver croaker”, plays an important role in the ecology and economy of Pará State, Brazil. Knowledge of host-parasite relationships is important to understanding the role of parasites in the control of natural host populations. This work describes histopathological aspects caused by several common intestinal parasites found during a helminthological survey of fish in northern Brazil. We observed a high prevalence of helminth infection, especially by J3 nematode juveniles of the family Anisakidae and metacestodes of the family Protocephalidae (both with 100% prevalence). An external capsule surrounded each juvenile with numerous juveniles inside sac-like structures formed of connective tissue. Inflammation was observed to be caused by infection of metacestodes, reaching the intestinal muscularis mucosa. Neoechinorhynchus veropesoi (38% prevalence) was found in the small intestine of P. squamosissimus, invading the mucosa, submucosa, and internal muscularis of the intestine causing intense inflammation. Histopathology of host-parasite relationships in fish has been rare, and the pathology of parasites in P. squamosissimus is described herein.

Plagioscion squamosissimus (Heckel, 1840) é uma espécie de peixe endêmico da Bacia Amazônica e comumente conhecido como “pescada branca” e é de extrema importância ambiental e comercial no Estado do Pará. O estudo das relações parasito-hospedeiro são importantes para a compreensão do papel dos parasitas no ambiente. O presente trabalho descreve aspectos histopatológicos causados por helmintos intestinais e cavitários encontrados parasitando P. squamosissimus de Belém, PA. As larvas da família Anisakidade e metacestóides (Proteocephalidae) (ambos prevalência de 100%) encontravam-se recobertas por uma cápsula de tecido conjuntivo do hospedeiro, sendo observada fraca reação inflamatória para larvas de Anisakidae, no entanto observou-se que metacestoides embebidos na muscular interna apresentaram um infiltrado inflamatório. Neoechinorhynchus veropesoi (prevalência de 38%) encontrava-se embebido na camada muscular interna do intestino, induzindo reação inflamatória mais intensa. Estudos evidenciando as reações histopatológicas em peixes são raros, no entanto são de extrema importância para a compreensão das relações parasito-hospedeiro.

Assessment of sanitary conditions of unregistered pig slaughter slabs and post mortem examination of pigs for Taenia solium metacestodes in Kaduna metropolis, Nigeria.

BACKGROUND: A number of studies document the prevalence of Taenia solium infections in Nigeria, yet these studies do not cover porcine cysticercosis in private home slaughter slabs where there is no routine meat inspection and backyard pig keeping, slaughtering and sale are common practice. METHODS: An environmental and sanitary assessment was conducted within two unregistered home pig slaughter slabs in selected parts of the Kaduna metropolis in Nigeria. Slaughter premises were inspected for availability of basic facilities and questionnaires were used to elicit necessary informative data. Butchers were examined for taeniasis by stool microscopy and copro-antigen enzyme linked immunosorbent assay (copro-Ag ELISA) to ascertain T. solium - taeniasis. Pigs slaughtered at the premises were examined for cysticerci. RESULTS: Home slaughter conditions were substandard, unhygienic and lacked the basic facilities of a proper slaughterhouse. Prevalence of porcine cysticercosis was 9.3%. The butchers participating in the study had very poor knowledge of T. solium infections and 30% tested positive for taeniasis by copro-Ag ELISA at the time of the study. CONCLUSION: Home slaughter of pigs in the areas studied should be considered and integrated as a component of prevention and control programmes - particularly through educational interventions - in order to equip individuals involved with a good understanding of the risks associated with animal husbandry and human practices.

Copépodos Notodiaptomus sp. Kiefer (Crustacea, Calanoida) naturalmente infectados com metacestódeos no reservatório do Juqueri, São Paulo, Brasil / Copepods Notodiaptomus sp. Kiefer (Crustacea, Calanoida) naturally infected by metacestodes in the Juqueri reservoir, São Paulo, Brazil

The aim of this work was to identify the components of zooplankton that act as intermediate hosts of cestodes. One hundred and ninety four copepods of the suborder Calanoida, 317 copepods of the suborder Cyclopoida and 4240 cladocerans were collected in the Juqueri reservoir, in the state of São Paulo, from January to August, 2003. Only Copepods Calanoida of the genus Notodiaptomus sp. Kiefer were found to be infected and contained two distinct forms of metacestodes. The metacestodes, denominated Met 1 (order Proteocephalidea) and Met 2 (order Cyclophyllidea), had the following rates of prevalence and mean intensities of infection: Met 1 - 2.06 percent and 64 larvae/copepod and Met 2 - 0.52 percent and one larvae/copepod. The positive copepods were collected at the margins of the reservoir during the day. This finding suggest that parasitism may lead to a change in the behavior of the copepods and make them more susceptible to predation in shallow water.

Este trabalho teve o objetivo de identificar os componentes do zooplâncton que atuam como hospedeiros intermediários de cestódeos. Foram examinados 194 copépodos da subordem Calanoida, 317 copépodos da subordem Cyclopoida e 4240 cladóceros coletados no reservatório do Juqueri, Estado de São Paulo, entre janeiro e agosto de 2003. Apenas copépodos Calanoida do gênero Notodiaptomus sp. Kiefer encontravam-se positivos, sendo relatada duas formas morfológicas distintas de metacestódeos. Os metacestódeos, denominados Met 1 (Proteocephalidea) e Met 2 (Cyclophyllidea) apresentaram as seguintes prevalências e intensidades médias de infecção: Met 1 - 2,06 por cento e 64 larvas/copépodo e Met 2 - 0,52 por cento e uma larva/copépodo. Os copépodos positivos foram coletados na região litorânea do reservatório durante o dia, o que leva a crer que o parasitismo pode modificar o comportamento dos copépodos tornando-os mais acessíveis à predação.

Immunoblot findings of calcareous corpuscles binding proteins in cyst fluid of Taenia solium metacestodes

After collecting calcareous corpuscles from plerocercoid of Spirometra mansoni (sparganum), we evaluated the antigenic values of calcareous corpuscles binding proteins obtained from the cyst fluid of Taenia solium metacestodes. Immunoblot analysis revealed that cysticercosis patient sera strongly recognized 10 and 95 kDa calcareous corpuscles binding proteins. This result demonstrated that calcareous corpuscles are bound with major secretory antigenic proteins, which is possibly involved in the secretory pathways of the 10 and 95 kDa proteins presenting in the cyst fluid of T. solium metacestodes.