Maria Teresa Galán-Puchades

Taenia asiatica: left out by globalisation?

A recent review article discusses how globalisation, related to the movement of people, animals, and food, affects the epidemiology of foodborne parasites [1].

Lights and shadows of the Taenia asiatica life cycle and pathogenicity.

Humans are definitive hosts of two well-known species of the Taenia genus, Taenia solium (the pig tapeworm) and Taenia saginata (the cattle tapeworm). In the 1990s, a third species, Taenia asiatica, was discovered, sharing features with the other two since the adult morphology is similar to that of T. saginata, but its life cycle is like that of T. solium. Human taeniasis usually is asymptomatic or displays mild symptoms, and only T. solium can cause other sometimes serious disorders when humans accidentally ingest the eggs and develop the larval stage in different organs (cysticercosis). In this review, we expose what we currently know (lights) and what we do not yet know (shadows) about the life cycle and pathogenicity of T. asiatica. Concerning its life cycle, the main uncertainty is whether humans can act as intermediate hosts of this species. We also suggest that due to its small size and location in pigs, the cysticerci probably escape veterinary inspection becoming a silent parasite. Concerning pathogenicity, it is still not known if T. asiatica can cause human liver cysticercosis, taking into account its principal hepatic tropism in pigs. To answer all these questions it would be essential to perform sensitive as well as specific diagnostic techniques for T. asiatica in humans and pigs. Currently, only molecular methods are able to determine the Taenia species, since morphology and immunology are useless, but unfortunately although largely used in research those methods are not employed in routine diagnosis.

The helminth community of the wood mouse Apodemus sylvaticus in a Mediterranean ecosystem in regeneration ten years after a wildfire.

This study was carried out 10 years after a wildfire in the Spanish Serra Calderona Natural Park, following a previous analysis comprising the first 5 years after the fire. Its primary aim was to elucidate the impact of this perturbation on the population biology of the wood mouse Apodemus sylvaticus, and the repercussions on its helminth community in this regenerating Mediterranean ecosystem. Second, confirmation of the ability of the parasites to tolerate environmental stressors and the effects on their transmission strategies was sought. Five hundred and sixty-four individuals of A. sylvaticus were studied in a 9-year period, from the second to the tenth post-fire year: 408 mice from the burned area and 156 from the control--non-burned--area. The helminth community for both areas and the effect of intrinsic (host age and sex) and extrinsic (site, period and year of capture) factors on helminth prevalence, abundance and diversity, and species richness were analysed. Our findings show that, after an environmental disaster, the behaviour of helminth species might be related to their pre-catastrophe presence, their biological cycles, the hosts immunological condition, the change of host dynamics, the direct effects of the perturbation, and the processes related to the re-establishment of the ecological balance of a devastated ecosystem.

The helminth community of the wood mouse Apodemus sylvaticus from the Erro River valley, Navarre, Spain.

The helminth fauna of the wood mouse, Apodemus sylvaticus, in the Erro River valley (Navarre, Spain) was investigated from a total of 150 mice between February 2001 and July 2002. An overall prevalence of 90.7% was recorded and up to 14 helminth species identified. The most prevalent species was the nematode Heligmosomoides polygyrus (78.0%), whereas Syphacia stroma was the species with the highest median abundance (19.8). The detection of Calodium hepaticum, Rodentolepis straminea and the larvae of Hydatigera taeniaeformis are significant, since these helminth species could be considered potential human parasites. The helminth infracommunity comprised no more than five species. A significant predominance of monoxenous species was detected. Statistically significant differences were also found between prevalences, helminth abundance, species richness and helminth diversity of sub-populations of the wood mouse determined by host age and season of capture, which agree with most of the studies carried out on this host. This study will shed light on the helminth community of the wood mouse from a region of Spain which has not previously been documented.

Diagnosis of Human Cysticercosis and Taenia asiatica

Zimic and others 1 evaluated the utility of a protein fraction with cathepsin L-like activity from Taenia solium in the diagnosis of human cysticercosis. To determine cross reactions, sera from infected patients with a single helminth were used. Specifically, and in addition to some nematode species, the tapeworms Hymenolepis nana, Taenia saginata, and Echinococcus granulosus , were tested. The highest specificity was reached in the Western immunoblot assay with a 98%. Since the 90s, a third human species, Taenia asiatica , has been recognized as a cause of human taeniasis. Taenia asiatica is an important human parasite at least in eight Asian countries, with a prevalence of up to 21% and causing annual economic losses of about US

On taeniasis, hydatidosis and 'figatellu'.

40,000,000 in those countries. 2

First survey on zoonotic helminthosis in urban brown rats (Rattus norvegicus) in Spain and associated public health considerations

p In a recent article, Halfon et al. diagnose a putative case of Taenia solium infection in a 55-year-old woman illustrating the finding with an interesting image of part of the parasite’s strobilum located in the patient’s intestine. They suggest the ingestion of ‘figatellu’, a typical deli meat from Corsica made with pork liver, four months earlier as the possible source of infection. Then, in a second paragraph, the authors explain what hydatidosis is and they even cite certain epidemiological data on porcine hydatidosis in Corsica [1]. Taeniasis and hydatidosis are two well-differentiated parasitic infections. We show the main differences between both helminthiases in Table 1. In the case of taeniasis, as the case presented in the article, humans act as the definitive host, harbouring the adult stage of the tapeworm in the intestine. In the case of hydatidosis caused by Echinococcus granulosus, humans act exclusively as intermediate hosts, harbouring the extra-intestinal (mainly in the liver or lungs) larval stage (hydatid cyst). Consequently, humans never harbour the intestinal adult stage of E. granulosus that is only present in the intestine of canids, mainly in dogs. Although the presence of porcine hydatidosis in Corsica is very interesting, as the authors point out, this is not related to the clinical case. Even in the case that the ingested ‘figatellu’ by

Taenia Species, Uterine Branches and Capsule Endoscopy

The brown rat, Rattus norvegicus, with a worldwide distribution, is the most commensal species among synanthropic rodents, since its main habitat, in urban as well as in rural areas, is always linked to humans. Therefore, people living in close proximity to rodent populations can be exposed to infection. Whereas bacteria and viruses are the best known rat-associated zoonoses in urban environments, the role of brown rats as reservoirs for helminth parasites and the associated risk for humans are less well known. Specifically, this role has not been analyzed in Spain to date. A total of 100 R. norvegicus trapped in the sewage system (n = 85), and parks (n = 15) of Barcelona was examined. The overall prevalence of helminth infection was 85%. The helminths found were Hymenolepis nana (17%), H. diminuta (33%) (Cestoda), Calodium hepaticum (17%), Eucoleus gastricus (28%), Aonchotheca annulosa (12%), Trichosomoides crassicauda (7%), Nippostrongylus brasiliensis (46%), Heterakis spumosa (62%), Gongylonema neoplasticum (20%) (Nematoda) and Moniliformis moniliformis (6%) (Acanthocephala). Five of the ten helminth species are considered zoonotic parasites, with rats acting as reservoirs for human infection, i.e. H. nana, H. diminuta, C. hepaticum, G. neoplasticum and M. moniliformis. G. neoplasticum and M. moniliformis are reported for the first time in urban rats in Europe. H. nana, H. diminuta and C. hepaticum are the most widespread species in European cities. For H. nana and C. hepaticum, rats act as effective spreaders of the human infective stage (eggs). For H. diminuta, G. neoplasticum and M. moniliformis, rats act as indirect reservoirs of the zoonoses since the eggs shed by the rats are infective for their insect intermediate hosts only. Medical practitioners need to be made aware of the range of parasites carried by rats, as there is a realistic likelihood that ill health currently caused by rat infestations may be misdiagnosed.

Pufferfish nests vs. parasite hooks: A bizarre resemblance

Hamada et al. show, in their article, several proglottids of an adult stage of a Taenia species in the small bowel of a woman by capsule endoscopy (1). One of the images clearly shows a gravid proglottid that allows the view of the characteristic Taenia uterus morphology, with a central axis and a n

Comment on “Epidemiological Survey on Porcine Cysticercosis in Nay Pyi Taw Area, Myanmar”

Graphical abstract Image 1