Tapeworms

First Report on Molecular Characterization of Taenia multiceps Isolates From Sheep and Goats in Faisalabad, Pakistan

Coenurus cerebralis is the larval stage of Taenia multiceps commonly found in the brain (cerebral form), intramuscular and subcutaneous tissues (non-cerebral form) of ungulates. Globally, few reports exist on the molecular characterization and genetic diversity of C. cerebralis with none available for Pakistan. The current study molecularly characterized 12 C. cerebralis isolates surgically recovered from sheep (n = 4) and goats (n = 8) from a total of 3,040 small ruminants using a portion of the cytochrome c oxidase subunit 1 (cox1) mitochondrial (mt) gene. NCBI BLAST search confirmed the identity of each isolate. A high haplotype and a low nucleotide diversity with three haplotypes from the 12 isolates were observed. The findings suggest the existence of unique haplotypes of C. cerebralis in Pakistan. The negative value of Tajima's D and the positive value of Fu's Fs were inconsistent with population expansion, however, the sample size was small. Bayesian phylogeny revealed that all Pakistani isolates alongside the Chinese sequences (obtained from GenBank) constituted a cluster while sequences from other regions constituted another cluster. This is the first molecular study to determine the genetic diversity of C. cerebralis in Pakistan and serves as a foundation for prospective studies on the prevalence and population structure of C. cerebralis in the country. Furthermore, in this study, we amplified only a partial segment of the cox1 gene from a limited sample size. This could have implications on the interpretation of the actual population structure in reality. Thus, we recommend future studies to consider a larger sample size in a massive epidemiological survey for further insights.

A parasitological evaluation of edible insects and their role in the transmission of parasitic diseases to humans and animals

From 1 January 2018 came into force Regulation (EU) 2015/2238 of the European Parliament and of the Council of 25 November 2015, introducing the concept of "novel foods", including insects and their parts. One of the most commonly used species of insects are: mealworms (Tenebrio molitor), house crickets (Acheta domesticus), cockroaches (Blattodea) and migratory locusts (Locusta migrans). In this context, the unfathomable issue is the role of edible insects in transmitting parasitic diseases that can cause significant losses in their breeding and may pose a threat to humans and animals. The aim of this study was to identify and evaluate the developmental forms of parasites colonizing edible insects in household farms and pet stores in Central Europe and to determine the potential risk of parasitic infections for humans and animals. The experimental material comprised samples of live insects (imagines) from 300 household farms and pet stores, including 75 mealworm farms, 75 house cricket farms, 75 Madagascar hissing cockroach farms and 75 migrating locust farms. Parasites were detected in 244 (81.33%) out of 300 (100%) examined insect farms. In 206 (68.67%) of the cases, the identified parasites were pathogenic for insects only; in 106 (35.33%) cases, parasites were potentially parasitic for animals; and in 91 (30.33%) cases, parasites were potentially pathogenic for humans. Edible insects are an underestimated reservoir of human and animal parasites. Our research indicates the important role of these insects in the epidemiology of parasites pathogenic to vertebrates. Conducted parasitological examination suggests that edible insects may be the most important parasite vector for domestic insectivorous animals. According to our studies the future research should focus on the need for constant monitoring of studied insect farms for pathogens, thus increasing food and feed safety.

Novel PCRs for differential diagnosis of cestodes

Cestodes or tapeworms belong to a diverse group of helminths. The adult Taenia saginata and Taenia solium tapeworm can infest the human gut and the larval stage of Echinococcus spp. and T. solium can infect tissues of the human body, causing serious disease. Molecular diagnostics can be performed on proglottids, eggs and on cyst fluids taken by biopsy. Detection of cestodes when a helminthic infection is suspected is of vital importance and species determination is required for appropriate patient care. For routine diagnostics a single test that is able to detect and type a range of cestodes is preferable. We sought to improve our diagnostic procedure that used to rely on PCR and subsequent sequencing of the Cox1 and Nad1 genes. We have compared these PCRs with novel PCRs on the 12S rRNA and Nad5 gene and established the sensitivity and specificity. A single PCR on the 12S gene proved to be very suitable for detection and specification of Taenia sp. and Echinococcus sp. Both targets harbour enough polymorphic sites to determine the various Echinococcus species. The 12S PCR was most sensitive of all tested.

An insect-tapeworm model as a proxy for anthelminthic effects in the mammalian host

Invertebrate models provide several important advantages over their vertebrate counterparts including fewer legislative stipulations and faster, more cost-effective experimental procedures. Furthermore, various similarities between insect and mammalian systems have been highlighted. To obtain maximum use of invertebrate models in pharmacology, their fidelity as analogues of vertebrate systems requires verification. We utilised a flour beetle (Tenebrio molitor)-tapeworm (Hymenolepis diminuta) model to evaluate the efficacy of known anthelmintic compounds, praziquantel, mebendazole and levamisole against H. diminuta cysticercoid larvae in vitro. Inhibition of cysticercoid activity during the excystation procedure was used as a proxy for worm removal. The effects of the three compounds mirrored their relative efficacy in treatment against adult worms in mammalian systems; however, further study is required to determine the fidelity of this model in relation to dose administered. The model precludes comparison of consecutive daily administration of pharmaceuticals in mammals due to cysticercoids not surviving outside of the host for multiple days. Treatment of beetles in vivo, followed by excystation of cysticercoids postdissection could potentially allow for such comparisons. Further model validation will include analysis of pharmaceutical efficacy in varying H. diminuta isolates and pharmaceutical dilution in solvents other than water. Notwithstanding, our results demonstrate that this model holds promise as a method to efficiently identify promising new cestocidal candidates.

Other cestodes: sparganosis, coenurosis and Taenia crassiceps cysticercosis

Many cestodes are capable of invading the central nervous system (CNS), and several are highly prevalent in the developing world. Neurocysticercosis due to Taenia solium and echinococcosis due to Echinoccocus granulosus are two of the most common parasitic infections affecting humans, but other less well-known parasites can also infect the nervous system. Coenurosis, caused by Taenia spp. such as T. multiceps, T. serialis, or T. brauni; sparganosis, caused by Spirometra spp., and neurocysticercosis caused by T. crassiceps are three less frequent zoonotic conditions that should be considered in the differential diagnosis of patients presenting with CNS infection - especially if they have lived in or traveled through areas where these infections are endemic. Diagnosis of these infections is typically made through a combination of serological testing, histopathology, and neuroimaging.

Effective Protection Against Experimental Taenia solium Tapeworm Infection in Hamsters by Primo-Infection and by Vaccination with Recombinant or Synthetic Heterologous Antigens

The disease caused by Taenia solium is progressively being recognized as a growing global threat for public human health and pig husbandry that requires the development of effective control measures. A central participant in the taeniasis/cysticercosis transmission network is the human carrier of the adult tapeworm because of its great potential in spreading the infection. Herein, evidence is presented that a primary infection of golden hamsters with orally administered T. solium cysticerci improved the host's resistance against a secondary infection. Likewise, previous vaccination increased the hamster's resistance. Similar high levels of protection (> 78%) were induced by systemic or oral vaccination with the S3Pvac anticysticercosis synthetic peptide vaccine or the highly immunogenic recombinant chimera based on the protective peptide KETc1 bound to Brucella spp. lumazine synthase (BLS-KETc1). Increased resistance after primo-infection and vaccination possibly results from changes in the immune conditions prevailing in the host's intestine. The contribution to protection from the KETc1 and BLS epitopes in a chimeric vaccine is under study. Preventive vaccination of definitive hosts of T. solium against the tapeworm, the most relevant step in the taeniasis/cysticercosis transmission, may greatly impact the dynamics of endemic disease and has not been studied or tried previously.

Epidemiology, clinical manifestations and diagnosis of zoonotic cestode infections: an update

This paper reviews the literature on zoonotic cestode infections with specific reference to the years 1999-2003. The sources and prevalence of various zoonotic tapeworm infections caused by adult and larval stages of the genera Taenia, Echinococcus, Diphyllobothrium, Hymenolepis and Dipylidium continue to be an important cause of morbidity and mortality, not only in most underdeveloped countries but also in industrialized countries, particularly in rural areas or among immigrant groups from endemic areas. The review gives a detailed report on recent molecular epidemiological studies on the taxonomy and phylogenetic variations in Echinococcus granulosus, immunological tests and imaging techniques used in epidemiological surveys and clinical investigations of important adult and larval tapeworm infections of animals and humans. Larval stages or metacestodes of Taenia solium, Echinococcus spp. and pseudophyllidean tapeworms (Spirometra syn. Diphyllobothrium spp.) may reside in various tissues of their intermediate hosts, including humans. In particular, Cysticercus cellulosae (T. solium) and the larvae of E. granulosus, and E. multilocularis, which are predominantly located in the liver, lungs and central nervous system forming various types of cysts, lead to a complex of systemic diseases such as cysticercosis, cystic echinococcosis and alveolar echinococcosis, respectively. Relatively rare clinical manifestations are seen in the muscles, subcutaneous tissue, spleen, kidneys, bones and body cavities.

Intestinal parasites

Although safe and efficacious broad-spectrum antiparasitic drugs have been developed, their availability for use in mass-treatment programs and for individual treatment worldwide can be limited by economic resources, existing manufacturing and distribution networks, and national regulations. Increasing population density, environmental pollution with human waste products, and global migration patterns will continue to promote transmission of human intestinal parasites in the foreseeable future because untreated or incompletely treated infected individuals can serve as roving reservoirs of infection for long-lived parasites. Asking primary care patients about possible geographic exposures and activities associated with an increased likelihood of intestinal parasite infection is an important part of the medical history. Many intestinal parasites can be treated effectively with oral medications, and treatment relatively early in the course of infection may prevent development of disease associated with chronic infections.

Submandibular and intracranial hydatid cyst in an adolescent

OBJECTIVES

An unusual case of hydatid disease is reported. Review of the pertinent literature did not reveal any hydatid disease located simultaneously in both the intracranial and submandibular glands. This is the first case with hydatid disease occurring in both locations at the same time.

STUDY DESIGN

The case of an 18-year-old is presented; the symptoms, findings, methods of diagnosis, and our approach for treatment are discussed; and the literature is reviewed.

RESULTS

The intracranial lesion was completely excised by left-sided frontoparietal craniotomy, and the mass in the right side of the submandibular gland was removed through a submandibular approach at the same session. The intact cyst was completely excised. Histological examination of both lesions confirmed the diagnosis of hydatid cyst by. Postoperative recovery was uneventful, and the patient was discharged on the seventh day.

CONCLUSIONS

Hydatid cyst should be suspected during the evaluation of cervical masses, particularly in endemic regions. Hydatid disease infestations are best treated with complete excision of the intact cyst.

Diphyllobothrium latum infection after eating domestic salmon flesh

Diphyllobothrium latum infection in human is not common in Korea and only thirty seven cases have been reported since 1921. We report two cases of fish tapeworm infection after ingestion of raw cherry salmon (Oncorhynchus masou) caught in the domestic river. Among four family members who ate together raw salmon flesh six months ago, just two, mother and daughter, were infected. It is our expectation that the salmon associated tapeworm infections would be enlisted as one of the major parasitic problems with the growing consumption of salmon in Korea.