Scorpion stings and spider bites

I try always to bring useful information to my blog, as I live and work in desert and at some weeks from summer I thought that a post about scorpion stings would be useful.

Written in  NETDOCTOR.COM  by Dr Charlie Easmon, specialist adviser in travel medicine


Exotic animal life is generally an attraction when travelling abroad, but some animals in particular have to be shown respect.
Most people are afraid of snakes, but other smaller creepy-crawlies may also pose a risk to humans – for example certain flying insects, such as wasps and bees.
Among the slightly larger and far more fascinating are scorpions and spiders.

Where are scorpions found?

Scorpions occur naturally in South, West and North Africa; North, Central and South America; India; and the Caribbean.
Among the scorpions in North America, the 'unpleasant' ones are typically to be found in Arizona, New Mexico and on the Californian side of the Colorado River, whereas the other North American species are fairly harmless.
In Mexico each year, 1000 to 2000 deaths occur from scorpion bites. Because of their size scorpions can easily travel anywhere in the world as stowaways with cargo, and they have been found in many large ports.

How can you avoid scorpion stings?

Scorpions are nocturnal animals and, therefore, typically only emerge at night. They often hide in dark cracks and vegetation. Ideally, accommodation should have a ledge that's at least 20cm high to prevent entry of scorpions.

• In areas with scorpions, it's also necessary to watch out for dark hiding places indoors: in cupboards, under the duvet and bed, or in shoes (look under the duvet and bed, and shake your shoes thoroughly before putting them on).
• In some countries, it's a popular sport to 'play' with scorpions – if you find it interesting to watch this torment, you should keep well away from the animal.
• Scorpions sting with a poisoned hook on their tail, which is typically raised prior to an attack.

Danger signals and symptoms

The majority of scorpions are harmless to humans, although the sting is extremely painful and will require painkilling treatment.
The following may be observed in cases of moderate to more serious poisoning:

• malaise, sweating, heart palpitations, rise in blood pressure, salivation, nausea, vomiting and diarrhoea. These symptoms should be treated in a similar way to snake bites, and a doctor should be consulted as quickly as possible.
• hyperacute (typically allergic) reactions in the form of blurring of consciousness, unconsciousness, convulsions, fall in blood pressure, shock and consequently the threat of death may occur.

Treatment of a scorpion sting

• Pain at the site of the sting can sometimes be limited with an ice cube.
• Painkilling injections (morphine-based painkiller) may be required, and a doctor should therefore be consulted. In the case of more marked symptoms, treatment must be given as for snake bites, and the patient must receive medical treatment as quickly as possible.
• There's antiserum for scorpion venom. Treatment must be overseen by a doctor.

Spiders

Some spiders are poisonous, but only a few can prove dangerous to humans. The glands responsible for producing the venom are located on the double-jointed upper jaws.
Spiders that pose the most risk include:

• the Australian Sydney funnel-web spider (Atrax robustus) that's often found in damp cellars, toilets or at swimming pools, particularly in New South Wales
• the North American 'brown recluse' (Loxosceles reclusa)
• the 'widow' group (for example the black widow: Lactrodectus sp.)
• the South American 'banana spider' (Phoneutria nigriventer)
• the tarantula that lives in South America and Mediterranean countries, whereas its very hairy big brother the 'bird spider' only lives in the wild in the Amazon (although it has become a popular collector's object for those who have an interest). Despite their significant or even enormous and fear-inducing appearance, the tarantulas are only directly dangerous to humans under particularly unfavourable conditions (such as allergy).

How do you avoid spider bites?

In principle, spiders are more difficult to avoid than scorpions, particularly as they often stay indoors and like to hunt during the day. They will often, but far from always, prefer slightly damp places in semi-shade.

Spider venom

Spider venoms have been chemically studied far less than snake venoms.
The venom of the 'widow' family (Lactrodectus sp.), like some snake venoms, can disturb the electrical impulses from nerves to muscles, and thereby induce paralysis. The venom of the 'recluse' family (Loxosceles sp.), in particular, causes local tissue damage and tissue death.
In principle, bites from the truly poisonous spiders should be treated like snake bites, and a doctor should be consulted as soon as possible. The spider should be killed and taken along to the doctor for identification.

People at particular risk

• People aged less than six years and more than 60 years.
• People with cardiovascular disease.
• People with a marked tendency towards allergic reactions.

Symptoms and danger signals

• A stinging, slightly smarting pain is often felt at the site of the bite. The pain can sometimes be burning and violent. In some cases, there's no immediate pain, but instead it comes on after 30 to 60 minutes. Blistering, bleeding under the skin and a convulsive sensation in the muscles may be felt. Later, local tissue death may occur, but this depends on the venom concerned.
• General symptoms such as anxiety, a sensation of weakness, sweating, headache, dizziness, swelling around the eyes, skin rash, respiratory distress, nausea, salivation and vomiting are all possible.
• Difficulty in maintaining muscle control and convulsions, which in the worst case can affect the muscles involved in swallowing and breathing.
• Possibly allergic reactions with circulatory failure, shock and death.

First aid and treatment for spider bites

• Ice cubes at the site of the bite may reduce the pain. In the case of bites from Loxosceles (the 'recluse' species), the ice should be packed to avoid causing further damage to tissue.
• Follow the guidelines for snake bites, including rapid transfer to a doctor or a hospital.
• There's antiserum for several spider venoms, and this treatment must be overseen by a doctor. 

 NETDOCTOR.COM