Search results for "Helminth"
showing 10 items of 363 documents
Taste, a new incentive to switch to (R)-praziquantel in schistosomiasis treatment.
2009
Background Praziquantel (PZQ) is the drug compound of choice in the control and treatment of schistosomiasis. PZQ is administered as a racemate, i. e. 1∶1 mixture of enantiomers. The schistosomicidal activity arises from one PZQ-enantiomer, whereas the other enantiomer does not contribute to the activity. The WHO's Special Programme for Research and Training in Tropical Diseases (TDR) has assigned the low-cost preparation of pure schistosomicidal (−)-PZQ a key priority for future R&D on PZQ, but so far this transition has not happened. PZQ has two major administration drawbacks, the first being the high dose needed, and its well documented bitter and disgusting taste. Attempts of taste-mask…
The parasite's long arm: a tapeworm parasite induces behavioural changes in uninfected group members of its social host.
2015
Parasites can induce alterations in host phenotypes in order to enhance their own survival and transmission. Parasites of social insects might not only benefit from altering their individual hosts, but also from inducing changes in uninfected group members. Temnothorax nylanderi ant workers infected with the tapeworm Anomotaenia brevis are known to be chemically distinct from nest-mates and do not contribute to colony fitness, but are tolerated in their colonies and well cared for. Here, we investigated how tapeworm- infected workers affect colony aggression by manipulating their presence in ant colonies and analysing whether their absence or presence resulted in behavioural alterations in…
Intermediate hosts of Angiostrongylus cantonensis in Tenerife, Spain.
2015
The nematode Angiostrongylus cantonensis is the causative agent of human angiostrongy- liasis, the main clinical manifestation of which is eosinophilic meningitis. Although this para- site has been found recently in its definitive rat host in Tenerife (Canary Islands, Spain), showing a widespread distribution over the north-east part of the island, there are no avail- able data regarding which snail and/or slug species are acting as intermediate hosts on this island. Consequently, the objective of this work was to determine the possible role of three mollusc species, Plutonia lamarckii , Cornu aspersum and Theba pisana , as intermediate hosts of A . cantonensis in Tenerife. Between 2011 and…
Protease-mediated processing of Argonaute proteins controls small RNA association
2020
SummarySmall RNA pathways defend the germlines of animals against selfish genetic elements and help to maintain genomic integrity. At the same time, their activity needs to be well-controlled to prevent silencing of ‘self’ genes. Here, we reveal a proteolytic mechanism that controls endogenous small interfering (22G) RNA activity in the Caenorhabditis elegans germline to protect genome integrity and maintain fertility. We find that WAGO-1 and WAGO-3 Argonaute (Ago) proteins are matured through proteolytic processing of their unusually proline-rich N-termini. In the absence of DPF-3, a P-granule-localized N-terminal dipeptidase orthologous to mammalian DPP8/9, processing fails, causing a cha…
S. haematobium as a Common Cause of Genital Morbidity in Girls: A Cross-sectional Study of Children in South Africa
2013
Background Schistosoma (S.) haematobium infection is a common cause of genital morbidity in adult women. Ova in the genital mucosal lining may cause lesions, bleeding, pain, discharge, and the damaged surfaces may pose a risk for HIV. In a heterogeneous schistosomiasis endemic area in South Africa, we sought to investigate if young girls had genital symptoms and if this was associated with urinary S. haematobium. Methodology In a cross-sectional study of 18 randomly chosen primary schools, we included 1057 schoolgirls between the age of 10 and 12 years. We interviewed assenting girls, whose parents had consented to their participation and examined three urines from each of them for schistos…
Life-history trade-offs in a generalist digenean from cetaceans: the role of host specificity and environmental factors
2015
Background Adults and larvae of generalist parasites are exposed to diverse hosts and local environmental conditions throughout their life cycles, thus local adaptation is expected to occur through phenotypic plasticity and/or natural selection. We investigated how the combined effect of cryptic host specificity and local selective pressures could shape reproductive traits of a putative generalist parasite in the oceanic realm. Methods The LSU rDNA, ITS2 and the mt-COI of individuals of the digenean Pholeter gastrophilus (Kossack, 1910) Odhner, 1914 (Heterophyidae Leiper, 1909) from oceanic striped dolphins, Stenella coeruleoalba Meyen, and coastal bottlenose dolphins, Tursiops truncatus Mo…
Helminths from the digestive tract of the striped dolphin (Stenella coeruleoalba) in the western Mediterranean: infection patterns within a long-term…
2015
0.1. INTRODUCCIÓN GENERAL 0.1.1. DIVERSIDAD Los cetáceos albergan una fauna específica de parásitos de transmisión trófica que incluye digeneos, cestodos, nematodos y acantocéfalos (Aznar et al., 2001; Raga et al., 2009). Dentro de los digeneos se han citado unas 40 especies pertenecientes a cuatro familias (Heterophyidae, Brauninidae, Notocotylidae y Brachycladiidae), la mayoría encontradas en el tracto digestivo de cetáceos, aunque algunas especies también parasitan los senos aéreos y los pulmones (Raga et al., 2009). Además, se han citado tres familias de cestodos (Tetrabothriidae, Diphyllobothriidae y Phyllobothriidae) que incluyen unas 30 especies (Aznar et al., 2001; Raga et al., 2009…
Helminth infracommunities of gallotia caesaris caesaris and gallotia caesaris gomerae (sauria: lacertidae) from the Canary islands (eastern Atlantic)
2004
A survey of gastrointestinal helminth communities of Gallotia caesaris caesaris (Lehrs, 1914) and G. c. gomerae (Boettger and Müller, 1914), from the islands of El Hierro and La Gomera, respectively, in the Canary Archipelago, Spain, was conducted to determine the prevalence, intensity, and diversity of intestinal parasites of these lacertid lizards. Larval forms of cestodes, nematodes, and acanthocephalans were found in the body cavity of G. c. caesaris; this lizard is the intermediate or paratenic host in the life cycle of these helminths. Pharyngodonid nematodes were the most common intestinal helminths in both hosts, 4 of them being Gallotia spp. specialists. Helminth infracommunities o…
Identifying and validating the presence of guanine-quadruplexes (G4) within the blood fluke parasite schistosoma mansoni
2021
Schistosomiasis is a neglected tropical disease that currently affects over 250 million individuals worldwide. In the absence of an immunoprophylactic vaccine and the recognition that mono-chemotherapeutic control of schistosomiasis by praziquantel has limitations, new strategies for managing disease burden are urgently needed. A better understanding of schistosome biology could identify previously undocumented areas suitable for the development of novel interventions. Here, for the first time, we detail the presence of G-quadruplexes (G4) and putative quadruplex forming sequences (PQS) within the Schistosoma mansoni genome. We find that G4 are present in both intragenic and intergenic regi…
Worm-like artifacts in exfoliative cytology.
2006
The presence of worms in cytological smears is occasionally reported, although various other structures exist that may be confused with such parasites. We present eight worm-like artifacts observed in routine Papanicolaou smears. Recognition of these structures is important to avoid overvaluation or confusion with true worms. Diagn. Cytopathol. 2006;34:636–639. © 2006 Wiley–Liss, Inc.