![Missulena occatoria ( Red-headed Mouse Spider ) [ Original photo copyright © Peripitus-2008-CC BY-SA 3.0 ]](images/spiders/SPP000791.jpg)
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Suborder: Mygalomorphae
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Family: Actinopodidae
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Genus: Missulena
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Species: occatoria
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Common Names
Mouse Spider
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Region
Australia
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Countries
Australia
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Taxonomy and Biology
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Size: Males : Total length ( excluding chelicerae and spinnerets ) about 12.5 mm. Legs I to IV with lengths about 15.7, 14.4, 13.7 and 16.4 mm respectively.
Females : Total length ( excluding chelicerae and spinnerets ) about 26.0 mm. Legs I to IV with lengths about 22.5, 21.6,22.5 and 25.5 mm respectively.
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Description
Males : Total length ( excluding chelicerae and spinnerets ) about 12.5 mm. Legs I to IV with lengths about 15.7, 14.4, 13.7 and 16.4 mm respectively.
Females : Total length ( excluding chelicerae and spinnerets ) about 26.0 mm. Legs I to IV with lengths about 22.5, 21.6,22.5 and 25.5 mm respectively.
Males : Carapace and chelicerae are shiny red or scarlet red, labium is reddish or reddish brown, legs are dark brown to black, abdomen dorsum is black ( not shiny ), abdomen venter is black and shiny and spinnerets are dark blackish brown.
Females : Carapace and chelicerae are dark brown or purplish brown, labium is reddish brown, legs, abdomen dorsum and venter is dark brown or purplish brown, spinnerets are brown.
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Venom
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General: Venom Neurotoxins
Excitatory neurotoxins
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General: Venom Myotoxins
Does not occur, based on current clinical evidence
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General: Venom Procoagulants
Not present
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General: Venom Anticoagulants
Not present
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General: Venom Haemorrhagins
Not present
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General: Venom Nephrotoxins
Not present
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General: Venom Cardiotoxins
Not present
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General: Venom Necrotoxins
Not present
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General: Venom Other
Not present or not significant
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Clinical Effects
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General: Dangerousness
Clinical effects uncertain, but related to medically important species, therefore major envenoming cannot be excluded.
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General: Rate of Envenoming: Unknown but likely to be low
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General: Untreated Lethality Rate: Unknown but lethal potential cannot be excluded
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General: Local Effects
Insufficient clinical reports to know
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General: Local Necrosis
Does not occur, based on current clinical evidence
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General: General Systemic Effects
Insufficient clinical reports to know
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General: Myotoxicity
Does not occur, based on current clinical evidence
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General: Coagulopathy & Haemorrhages
Does not occur, based on current clinical evidence
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General: Renal Damage
Does not occur, based on current clinical evidence
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General: Cardiotoxicity
Does not occur, based on current clinical evidence
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General: Other
Insufficient clinical reports to know
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First Aid
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Description: First aid for Funnel Web Spider Bites (Australia)
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Details
1. If the spider is still attached, immediately remove it, being careful not to sustain further bites, and place to spider in a jam jar or other container, so it may be brought to the hospital for identification.
2. After ensuring the patient and onlookers are no longer at risk of further bites by the spider, the bitten person should be reassured and persuaded to lie down and remain still. Many will be terrified, fearing sudden death and, in this mood, they may behave irrationally or even hysterically. The basis for reassurance is the fact that many bites do not result in envenoming, and the effectiveness of modern medical treatment.
3. The bite wound should not be tampered with in any way.
4. If the bite is on a limb, a broad bandage (even torn strips of clothing or pantyhose) should be applied over the bitten area at moderate pressure (as for a sprain; not so tight circulation is impaired), then extended to cover as much of the bitten limb as possible, including fingers or toes, going over the top of clothing rather than risking excessive limb movement by removing clothing. The bitten limb should then be immobilised as effectively as possible using an extemporised splint or sling.
5. If there is any impairment of vital functions, such as problems with respiration, airway, circulation, heart function, these must be supported as a priority. In particular, both airway and respiration may be impaired, requiring urgent and prolonged treatment, which may include the mouth to mask (mouth to mouth) technique of expired air transfer. Seek urgent medical attention.
6. Do not use Tourniquets, cut, suck or scarify the wound or apply chemicals or electric shock.
7. Avoid peroral intake, absolutely no alcohol. No sedatives outside hospital. If there will be considerable delay before reaching medical aid, measured in several hours to days, then give clear fluids by mouth to prevent dehydration.
8. If the offending spider has been killed or caught it should be brought with the patient for identification. Many relatively harmless spiders may appear similar to the funnel web spiders and there are several species of funnel web spiders, so identification of the spider is important.
9. The spider bite victim should be transported as quickly and as passively as possible to the nearest place where they can be seen by a medically-trained person (health station, dispensary, clinic or hospital). The bitten limb must not be exercised as muscular contraction will promote systemic absorption of venom. If no motor vehicle or boat is available, the patient can be carried on a stretcher or hurdle, on the pillion or crossbar of a bicycle or on someone's back.
10. Most traditional, and many of the more recently fashionable, first aid measures are useless and potentially dangerous. These include local cauterization, incision, excision, amputation, suction by mouth, vacuum pump or syringe, combined incision and suction ("venom-ex" apparatus), injection or instillation of compounds such as potassium permanganate, phenol (carbolic soap) and trypsin, application of electric shocks or ice (cryotherapy), use of traditional herbal, folk and other remedies including the ingestion of emetic plant products and parts of the snake, multiple incisions, tattooing and so on.
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Treatment
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Treatment Summary
Mouse spiders may, rarely, cause effects similar to funnel web spider bites, therefore can potentially cause severe, possibly fatal envenoming rapidly, so all cases should be managed as a medical emergency. At the first sign of systemic envenoming, IV CSL Funnel Web Spider Antivenom should be given, 2-4 vials initially, depending on severity, followed by further doses if envenoming persists or recurs.
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Key Diagnostic Features
Painful bite, rapid development of systemic envenoming, with perioral tingling, tongue fasciculation, headache, nausea, increased sweating, salivation, lachrymation, piloerection, hypertension, pulmonary oedema.
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General Approach to Management
It is possible that most cases will be minor, but some cases may be more severe, requiring admission and treatment, so assess carefully before discharge.
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Antivenom Therapy
Only antivenoms available are for related species, but should be used for significant envenoming
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