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    Notes on Scorpions of Medical Significance (additional notes) long read but informative

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    Arachnida Elders
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    Notes on Scorpions of Medical Significance (additional notes) long read but informative

    Post by Fire Starter on Sat Sep 12, 2009 12:43 pm

    Sharing some information i found on the net!

    The following is a concise version of an article written for the Forum Magazine of the American Tarantula Society. I thought that some of the neophyte keepers would find the information useful. It's presented as an unofficial SOTM.

    Concise Checklist of the Buthid Scorpions of Medical Significance

    Lucian K. Ross
    medsig.buthidae@yahoo.com


    McWest (2003) produced a brief review of scorpions of medical significance in the Forum Magazine of the American Tarantula Society (12(4): 139). While the review contained a listing of 29 buthid species of which the venom of the majority of species listed has been confirmed to produce moderate to fatal systemic reactions in humans, a small number of the listed buthid species and their medical significance were indicated by the author with a question mark as either being questionable or unknown. One important omission from the listing of McWest (2003) was that of Leiurus quinquestriatus (two subspecies: L. q. quinquestriatus and L. q. hebraeus).
    The following annotated checklist of medically significant scorpions focuses solely on the members of the family Buthidae. At present, all but two of the currently recognized species of medical importance belong to this speciose family of primarily cosmotropical scorpions from the New and Old World. At present, the family Buthidae is comprised of 811 species representing 47.8% of the approximately 1700 described scorpion species. As of this writing, 68 (8.4%) buthid species have either been implicated in systemic and fatal envenomations in humans or suspected of being able to produce potentially life-threatening effects based on LD50 values and/or venom composition. Also, while many genera of medically significant scorpions are reported for the Old World region, only the Nearctic and Neotropical genera Centruroides and Tityus are responsible for severe and fatal envenomation in the New World.
    While the compilation of such a listing would seem an uncomplicated, straightforward task involving a simple review of the published medical, toxicological and toxinological literature, many complications exist that make any such listing incomplete. LD50 venom toxicity levels can vary greatly between geographic populations and the strain, age, weight and sex of the test animals used and how the venom was introduced into test animals (e.g. subcutaneous) can modify the results of such tests. In several countries within North Africa and the Middle East, a scorpion being identified simply as a “yellow” scorpion in a published source may represent Androctonus amoreuxi, Androctonus australis, Leiurus quinquestriatus, or any one of a number of local Buthus spp. (e.g. B. occitanus).
    Another factor that complicates the accuracy in reporting an envenomation is that species are often not identified, misidentified or simply identified based on color (e.g. “yellow” scorpion). In many regions, unknown numbers of non-fatal and fatal envenomations may go unreported to local medical facilities and poison control centers. To a lesser extent, fatalities may not be reported from remote localities in developing nations. In the United States, many localized and mild systemic envenomations caused by Centruroides sculpturatus are not reported to medical facilities or local poison control centers and are treated at home with the administration of ice and analgesics.
    In other regions, scorpions of potential medical significance remain unidentified due to their distribution in wild areas remote from human habitation. In other regions, severe and fatal envenomations from recognized medically significant scorpion species remain unreported. While Androctonus australis produces severe to fatal envenomations in many regions of North Africa and the Middle East, no fatalities due to envenomations from Sinai populations of this species are reported in the medical literature of the region.
    Another significant factor that has to always be taken into account regardless of the medical significance of the species being discussed is that all medically significant scorpions produce moderate to high rates of adult and pediatric morbidity and low rates of pediatric mortality, with fatalities among healthy adults being uncommon. Fatalities are generally limited to children under 16-years of age, particularly those in the 0-5 year group. In some species, the elderly are at equal risk with children for severe and fatal reactions to envenomations due to lower body mass and pre-existing health conditions. Overall, based on existing statistics available for all medically significant scorpion species, adult fatalities are infrequent and only represent a very small number of reported fatalities due to scorpion envenomation.
    As of this writing, several members of the following buthid genera have been confirmed to produce moderate to fatal envenomations in humans: Androctonus, Buthus, Centruroides, Hottentotta, Leiurus, Mesobuthus, Odontobuthus, Parabuthus, and Tityus. As a precautionary note, all members of the listed genera should never be handled and should always be treated with suspicion and respect regarding their possible medical significance. For example: while Androctonus amoreuxi has not been confirmed to cause medically significant results in humans, its reported LD50 toxicity is 0.75 mg/kg, which indicates that it has the potential to cause at least severe systemic reactions in humans. On the other hand, envenomations by species such as Centruroides margaritatus and Tityus obtusus from medically significant genera produce only localized or slight systemic effects in humans.
    For this contribution, a medically significant scorpion species is defined as any species whose venomic components are capable or potentially capable of producing at least moderate systemic effects in humans or the chemical composition or actions of the various venomic components are able to produce severe or fatal responses in victims of envenomations. Species listed in parenthesis have either been implied as being of potential medical significance based on factors such as LD50 toxicity values (Androctonus amoreuxi) or have been implicated in severe or fatal envenomations based upon only a speculative or non-confirmed identification (Parabuthus capensis). All species contained in this listing should be considered potentially dangerous to humans, especially in children between the ages of 0–16 years.
    The following species listing is based upon the worldwide medical, toxicological and toxinological literature published from 1900 to 2007. Based upon the factors discussed above and many other factors not listed, the species listing is based upon published reports and case studies in which, moderate to fatal medical significance has been confirmed and substantiated in the pertinent literature or suspected of being able to produce potentially life-threatening effects in humans based on published LD50 values (species listed in parentheses). In some literary sources, scorpion species suspected of presenting potential danger to humans (e.g. Androctonus hoggarensis) without published studies or cases substantiating such claims have been omitted from the current list. Due to the lack of medical and toxicological reports regarding venom toxicities and potential effects in humans in the majority of buthid scorpions, the list remains tentative and incomplete.

    FAMILY BUTHIDAE C. L. KOCH, 1837 (ARACHNIDA: SCORPIONES)

    GENUS ANDROCTONUS EHRENBERG, 1828

    (A. amoreuxi) (Audouin, 1826)
    A. australis (see Note 1) (Linnaeus, 1758)
    A. bicolor (see Note 2) Ehrenberg, 1828
    A. crassicauda (Olivier, 1807)
    A. liouvillei (Pallary, 1924) (see Note 3)
    A. mauritanicus (Pocock, 1902)

    GENUS BUTHUS LEACH, 1815

    B. occitanus (Amoreux, 1789) (see Note 4)
    B. tunetanus (Herbst, 1800)

    GENUS CENTRUROIDES MARX, 1890

    C. elegans (Thorell, 1876) (see Note 5)
    C. gracilis (Latreille, 1804) (see Note 6)
    C. griseus (C. L. Koch, 1844)
    C. infamatus (C. L. Koch, 1844) (see Note 7)
    C. limbatus (Pocock, 1898) (see Note Cool
    C. limpidus (Karsch, 1879) (see Note 9)
    C. noxius Hoffmann, 1932 (see Note 10)
    C. pallidiceps Pocock, 1902
    C. sculpturatus Ewing, 1928 (see Notes 11)
    C. suffusus (Pocock, 1902) (see Note 12)
    C. vittatus (Say, 1821) (see Notes 13)

    GENUS HOTTENTOTTA BIRULA, 1908

    H. gentili (Pallary, 1924) (see Note 14)
    H. hottentotta (Fabricius, 1787)
    H. judaicus (Simon, 1872) (see Note 15)
    H. minax (L. Koch, 1975)
    H. saulcyi (Simon, 1828)
    H. tamulus (Fabricius, 1798)
    H. trilineatus (Peters, 1861)

    GENUS LEIURUS EHRENBERG, 1828 (excluded from McWest 2003)

    L. quinquestriatus (Ehrenberg, 1828)

    GENUS MESOBUTHUS VACHON, 1950

    M. eupeus (C. L. Koch, 1839)
    M. gibbosus (Brulli, 1832) (see Note 16)
    M. martensii (Karsch, 1879)

    GENUS ODONTOBUTHUS VACHON, 1950

    (O. doriae) (Thorell, 1876)

    GENUS PARABUTHUS POCOCK, 1890

    (P. capensis) (Ehrenberg, 1831)
    P. granulatus (Ehrenberg, 1831)
    P. mossambicensis (Peters, 1861)
    P. transvaalicus Purcell, 1899

    GENUS TITYUS C. L. KOCH, 1836

    T. arellanoparrai Gonzalez-Sponga, 1985
    T. argentinus Borelli, 1899
    T. asthenes Pocock, 1893 (see Note 17)
    T. bahiensis (Perty, 1833)
    T. brazilae Lourenco & Eickstedt, 1984
    T. cambridgei Pocock, 1897
    T. caripitensis Quiroga, De Sousa & Parrilla-Alvarez, 2000
    T. charreyroni Vellard, 1932
    T. costatus (Karsch, 1879)
    T. dasyurus Pocock, 1897
    T. dedoslargos Francke & Stockwell, 1987
    T. discrepans (Karsch, 1879)
    T. falconensis Gonzalez-Sponga, 1974 (see Note 18)
    T. fasciolatus Pessoa, 1935
    T. forcipula (Gervais, 1843)
    T. fuehrmanni Kraepelin, 1914
    T. funestus Hirst, 1911
    T. ivicnancor Gonzalez-Sponga, 1997
    T. mattogrossensis Borelli, 1901
    T. monaguensis Gonzalez-Sponga, 1974
    T. neglectus Mello-Leitao, 1932
    T. nematochirus Mello-Leitao, 1940
    T. neoespartanus Gonzalez-Sponga, 1996 (see Note 19)
    T. nororientalis Gonzalez-Sponga, 1996
    T. pachyurus Pocock, 1897
    T. perijanensis Gonzalez-Sponga, 1994 (see Note 20)
    T. quirogae De Sousa, Manzanilla & Parrilla-Alvarez, 2006
    T. serrulatus Lutz & Mello, 1922
    T. silvestris Pocock, 1897
    T. stigmurus (Thorell, 1876) (see Note 21)
    T. surorientalis Gonzalez-Sponga, 1996
    T. tamayoi Gonzalez-Sponga, 1987
    T. trinitatis Pocock, 1897 (see Note 22)
    T. trivittatus Kraepelin, 1898
    T. zulianus Gonzalez-Sponga, 1981

    NOTES:

    Note 1: All references to the former subspecies Androctonus australis garzonii and A. a. hector can be attributed to the species A. australis.
    Note 2: This species has been reported in the literature under various synonyms including Androctonus aeneas.
    Note 3: This species has been reported in the literature as Androctonus aeneas liouvillei.
    Note 4: Medical significance has only been reported in North African and Middle Eastern populations.
    Note 5: Includes Centruroides elegans elegans.
    Note 6: Medical significance has been confirmed for Colombian populations of this species and anecdotally for other Central and South American populations.
    Note 7: Includes Centruroides infamatus infamatus.
    Note 8: Medical significance is based upon a single reported envenomation by this species in Orange County, California (U.S.A.), outside its natural distribution range.
    Note 9: Includes Centruroides limpidus limpidus and C. l. tecomanus.
    Note 10: The venom of this species (LD50 0.31 mg/kg) is as toxic as members of the Old World genera Androctonus and Leiurus.
    Note 11a: While once synonymized with C. exilicauda of Baja California (Mexico), only C. sculpturatus has produced medically significant responses in humans. The venom of C. exilicauda is not considered medically significant.
    Note 11b: In the United States, no fatal envenomations have been reported for this species since 1968. However, multiple fatalities have occurred since 1968 as a result of hypersensitive (allergic) reactions to the venom of this species.
    Note 12: Includes Centruroides suffusus suffusus.
    Note 13a: A single fatal envenomation attributed to this species has been reported from Texas (U.S.A.).
    Note 13b: Fatality was due to an allergic reaction to the venom of this species.
    Note 14: Reported as Hottentotta franzwerneri gentili in the literature.
    Note 15: This species has produced clonic-tonic seizures (convulsions) in envenomation victims.
    Note 16: The venom of this species has been confirmed as being lethal to humans.
    Note 17: While no fatalities have been reported for this species, its venom has been confirmed to produce severe, potentially life-threatening results in humans.
    Note 18: While this species has not been reported as causing human fatalities, its venom contains abundant cardiotoxic components and it is responsible for all severe envenomations reported in the State of Falcón, Venezuela.
    Note 19: This species was recently identified in causing two severe envenomations from Margarita Island, Venezuela.
    Note 20: The LD50 toxicity value for this species is reported at 0.91–0.94 mg/kg. It is also considered the most toxic of Venezuelan Tityus spp.
    Note 21: Fatality rates for this species are lower than has been reported in anecdotal accounts.
    Note 22: While the medical significance of this species was listed as unknown by McWest (2003), it is responsible for all fatal envenomations reported in Trinidad and is the only scorpion species of medical significance identified in the entire Caribbean Region (Antilles or West Indies). Its venom produces high rates of acute pancreatitis in envenomation victims. In one study on scorpion envenomations in Trinidad, 24 of 30 (80%) patients developed acute pancreatitis as a result of nephrotoxic components contained in the venom of this species.


    Last edited by Fire Starter on Wed Apr 21, 2010 1:58 am; edited 1 time in total
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    Arachnida Elders
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    Re: Notes on Scorpions of Medical Significance (additional notes) long read but informative

    Post by Fire Starter on Wed Apr 21, 2010 1:56 am

    Actually, the rule of thumb is that large, well developed chelae (pincers) (typical of diplocentrids and scorpionids) generally indicate a scorpion species whose venom is innocuous and those with more gracile, elongate, and weakly developed chelae (typical of buthids) indicate species with more toxic (medically significant) venoms. The size and shape of the telson indicates very little. The dimensions of the metasomal segments are of use primarily to identify some taxa of scorpions such as members of the genera Androctonus and Parabuthus - both members of the family Buthidae.

    To date, all but two of the approximately 50 scorpion species with medically significant venoms are members of the largely cosmotropical taxon Buthidae. The remaining two species are Hemiscorpius lepturus (Hemiscorpiidae) and Nebo hierichonticus (Diplocentridae). Buthid taxa containing medsig species are: Androctonus, Buthus, Centruroides, Hottentotta, Leiurus, Mesobuthus, Odontobuthus, Parabuthus, and Tityus. All are Old World elements except the genera Centruroides and Tityus, which are exclusively limited to the New World (sans Old World introductions of Centruroides gracilis).

    At present, the species with the most potentially toxic venoms with mammalian-specific components are the buthids Odontobuthus doriae and Leiurus quinquestriatus (based on published LD50 values). Members of the genera Androctonus and Centruroides produce more human fatalities among the young and elderly than members of other genera. Next in numbers of fatalities would be members of Tityus and Leiurus. However, regardless of the published LD50 value or epidemiological reports (most flawed or incomplete in some way), mortality due to scorpionic envenomations have been quite exaggerated and over-dramatized. One such example is the arenicolous buthid L. quinquestriatus. While it is certainly true that the venom of this species has caused a goodly number of fatalities in humans and large numbers of morbidities, it is no more a deathstalker than any other medsig scorpion species! Actually, for its limited distribution and populace throughout its distribution range, A. mauritanicus is probably one of the leading producers of fatalities in humans (primarily in the 0-15 year age group) with 60% of human mortalities in Morocco attributed to this species! Annually, there are approximately 1.2 million reported scorpionic envenomations from an at risk population of 2.3 billion, with only 3200-3300 of those resulting in mortality (~0.27% global mortality rate per annum). The majority of these envenomations producing fatalities are largely attributed to several Mexican species within the genus Centruroides and the neotropical genus Tityus!

    Overall, any scorpion producing medically significant venom may produce morbidity and to a far lesser extent, mortality in humans. There is no "deadliest" species because so many variables must be taken into account that it's impossible to pre-determine how any individual will react to one or more venomic components under a broad-range of potential circumstances - if a reaction occurs at all. Tityus serrulatus is considered to be the most medically significant scorpion species in South America (not really true!) but fatalities are very rare but high rates of morbidity do occur. The majority of A. australis and L. quinquestriatus envenomations produce only localized or slight systemic reactions in humans. The majority of scorpionic envenomations produce innocuous or slight systemic manifestations and little else.

    The best advice for anyone is to give these animals the awe and respect they deserve; work with them safely using the proper tools and secure enclosures in order to decrease the chances of receiving an envenomation. While the term "aggressive" is quite behaviorally inaccurate to describe any suite of behaviors exhibited by scorpions including defensive actions/reactions, scorpions may become highly-defensive in reaction to stimuli that they perceive as threatening or antagonistic and react accordingly. However, if kept properly and securely, there is no need for any scorpion to be considered "deadly" to its keeper.

    Lastly, as Michiel aptly stated in a previous post regarding the topic of amputation. This would probably only occur under extremely unusual circumstances and probably only in regards to hyper-dermonecrotic manifestations cytotoxically produced in an individual by the venom of Hemiscorpius lepturus.

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