16,318 research outputs found
Leech Parasitism of the Gulf Coast Box Turtle, Terrapene carolina major (Testudines:Emydidae) in Mississippi, USA
Ten leeches were collected from a Gulf Coast box turtle, Terrapene carolina major, found crossing a road in Gulfport, Harrison County, Mississippi, USA. Eight of the leeches were identified as Placobdella multilineata and 2 were identified as Helobdella europaea. This represents the second vouchered report of leeches from a box turtle. Helobdella europaea is reported for the first time associated with a turtle and for the second time from the New World
Ingestive behaviour and physiology of the medicinal leech
Ingestion lasts 25 min in Hirudo medicinalis and is characterized by pharyngeal peristalsis which fills the crop. This peristalsis has an initial rate of 2.4 Hz which decays smoothly to 1.2 Hz at termination of ingestion. During ingestion, the leech body wall undergoes peristalsis which appears to aid in filling the crop diverticula. Body peristalsis begins at a rate of 10 min^(-1) and decreases linearly to 2 min^(-1) at termination. The body also undergoes dorsoventral flexions when blood flow is occluded. Blood meal size increases slightly with leech size: 8.4 g for 1-g leeches and 9.7 g for 2-g leeches. However, relative meal size decreases markedly with increasing animal size; from 8.15 times body mass for 1-g to 4.80 times for 2-g leeches. When intact leeches were exposed to micromolar concentrations of serotonin, there was an increase in the rate of pharyngeal peristalsis and the size of the blood meals. Leeches excrete the plasma from their ingested blood meals. Excretion is activated during ingestion, which increases feeding efficiency by increasing the proportion of blood cells in the ingestate. Excretion continues for 4–6 days following ingestion, removing all the remaining plasma from the ingestate. Leech ingestion comprises stereotyped muscular movements, secretion of saliva and excretion of plasma. A strikingly similar feeding physiology is seen in the blood-sucking insect Rhodnius, and we suggest that efficient sanguivory may require the convergent evolution of similar ingestive mechanisms
The medicinal use of leeches in Malta
The medical practice based on the Greek doctrine of the four humors considered that disease was due to alterations in the composition of these humors, and therapy was therefore based on attempting to restore the balance. Bleeding was the first resort in the treatment of a large majority of diseases a therapeutic measure that persisted throughout the centuries. Bloodletting generally took the form of using a knife or lancet to open a vein, a procedure referred to as venesection or phlebotomy. A gentler and more desirable form of bleeding was to put a leech on the affected part and to let the animal engorge itself with the bad blood thought to dwell below the point of application. Leeches have been used medically for centuries; in Europe the use of leeches to drain off blood reached its height of popularity in the 19th century. The practice of bloodletting in the Maltese Islands dates at least to about the 2nd century AD. A tomb-slab from the late Roman/Palaeo-Christian period depicts a set of surgical instruments that include two Roman cupping vessels 1. Only 93 kilometers away from Sicily and 290 km from Northern Africa, the Maltese archipelago with its central position in the Mediterranean was an important meeting place for the various cultures that dominated the region. Malta's location at the crossroads of culture is reflected by the medical practices in use throughout the centuries. The practice of venesection in Malta persisted through the ages and during the medieval period (1539), the procedure was being carried out by the barbersurgeons against payment of one unza2. The barber-surgeons or barberotti remained responsible for venesection well into the 19th century and were only removed from the list of medical practitioners in 19213. The gentler form of bloodletting through the use of leeches was also practiced in Malta.peer-reviewe
Provisional atlas of the freshwater leeches of the British Isles
Distribution maps were included in the second edition of the F.B.A. Scientific Publication on British freshwater leeches (Mann 1964). When that publication was extensively revised and enlarged to include a review of the literature on the ecology of leeches (Elliott & Mann 1979), it was decided that new maps should be published separately. The original maps were based on 1097 records whereas 4198 records were used for the new maps. The total British Isles list comprises sixteen species, thirteen genera and four families of leeches
Toxic effect of Raphia vinifera on fish leech (Piscicola geometra)
This study examines acute toxicity of Raphia vinifera on fish leech, Piscicola geometra. The leeches with a mean total length of (TL) 4.2+1.0cm were exposed to various concentrations of both crude powdered and ethanolic extracts of the botanical. Median lethal concentration (LC50) was determined with static-renewal tests using logarithmic and arithmetic graphic methods. The LC50 (for 96 hours of crude powdered (aqueous) extracts of the botanical on Piscicola geometra was 1.10 ppm arithmetically and 1.14ppm logarithmically. The 95% confidence limits was 0.10ppm arithmetically and 0.12ppm logarithmically. The LC50 of ethanolic extract of the poison at 96-h was 0.5ppm arithmetically and 0.48ppm logarithmically. The 95% confidence limits were less than 0.10ppm. The use of extracts of R. vinifera in the control of leeches in fish ponds is discusse
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Occurrence, distribution and bibliography of the medicinal leech Hirudo verbana Carena, 1820 (Hirudinea, Hirudinidae) in Sicily (Italy)
The occurrence of the medicinal leech Hirudo verbana in the inland waters of Sicily has been lately overlooked. In the present note, the occurrence and distribution of this species is reviewed based both on the review of the available literature data and field collecting. Although a noteworthy reduction in the distribution range of the species seems to have taken place in Sicily in the course of the XX century, Hirudo verbana was confirmed to be still present in several sites located both within and out of Natura2000 sites. The Sicilian populations of the species should be included in the frame of the monitoring activities established by the Article 17 of the EU Council Directive 92/43/EEC (“Habitats Directive”)
Automated Video Analysis of Animal Movements Using Gabor Orientation Filters
To quantify locomotory behavior, tools for determining the location and shape of an animal’s body are a first requirement. Video recording is a convenient technology to store raw movement data, but extracting body coordinates from video recordings is a nontrivial task. The algorithm described in this paper solves this task for videos of leeches or other quasi-linear animals in a manner inspired by the mammalian visual processing system: the video frames are fed through a bank of Gabor filters, which locally detect segments of the animal at a particular orientation. The algorithm assumes that the image location with maximal filter output lies on the animal’s body and traces its shape out in both directions from there. The algorithm successfully extracted location and shape information from video clips of swimming leeches, as well as from still photographs of swimming and crawling snakes. A Matlab implementation with a graphical user interface is available online, and should make this algorithm conveniently usable in many other contexts
New Host and Geographic Distribution Records for the Fish Leech Myzobdella reducta (Meyer, 1940) (Hirudinida: Piscicolidae)
iDNA from terrestrial haematophagous leeches as a wildlife surveying and monitoring tool - prospects, pitfalls and avenues to be developed
Invertebrate-derived DNA (iDNA) from terrestrial haematophagous leeches has recently been proposed as a powerful non-invasive tool with which to detect vertebrate species and thus to survey their populations. However, to date little attention has been given to whether and how this, or indeed any other iDNA-derived data, can be combined with state-of-the-art analytical tools to estimate wildlife abundances, population dynamics and distributions. In this review, we discuss the challenges that face the application of existing analytical methods such as site-occupancy and spatial capture-recapture (SCR) models to terrestrial leech iDNA, in particular, possible violations of key assumptions arising from factors intrinsic to invertebrate parasite biology. Specifically, we review the advantages and disadvantages of terrestrial leeches as a source of iDNA and summarize the utility of leeches for presence, occupancy, and spatial capture-recapture models. The main source of uncertainty that attends species detections derived from leech gut contents is attributable to uncertainty about the spatio-temporal sampling frame, since leeches retain host-blood for months and can move after feeding. Subsequently, we briefly address how the analytical challenges associated with leeches may apply to other sources of iDNA. Our review highlights that despite the considerable potential of leech (and indeed any) iDNA as a new survey tool, further pilot studies are needed to assess how analytical methods can overcome or not the potential biases and assumption violations of the new field of iDNA. Specifically we argue that studies to compare iDNA sampling with standard survey methods such as camera trapping, and those to improve our knowledge on leech (and other invertebrate parasite) physiology, taxonomy, and ecology will be of immense future value
Molecular Aspect of Annelid Neuroendocrine system
Hormonal processes along with enzymatic processing similar to that found in
vertebrates occur in annelids. Amino acid sequence determination of annelids
precursor gene products reveals the presence of the respective peptides that
exhibit high sequence identity to their mammalian counterparts. Furthermore,
these neuropeptides exert similar physiological function in annelids than the
ones found in vertebrates. In this respect, the high conservation in course of
evolution of these molecules families reflects their importance. Nevertheless,
some specific neuropeptides to annelids or invertebrates have also been in
these animals
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