Myriapoda
millipedes/centipedes

Arachnida
scorpions/spiders

Arthropoda
insects

Vertebrata
reptiles/mammals


Animal-related Injuries relevant to the Maltese Islands - Terrestial


Arachnida

The class Arachnida comprises animal species belonging to eleven different Orders of which only six are represented on the Maltese Islands. Some species of the Order Acari comprising the ticks and mites are parasitic on man and can transmit disease.


Order Scorpiones: Scorpions

The only species of scorpion Euscorpius carpathicus found in Malta is small and has only a mild poison which it delivers from its poison sting at the end of its tail. The relative innocuousness of the Maltese scorpion was remarked upon in the first published description of the Maltese Islands Insulae Melitae by Jean Quintinus d'Autum published in 1536. Quintinus writes that "Scorpions, fearful animals elsewhere, are seen here innocuous in the hands of boys playing with them; I myself saw one eating them."

Order Araneae: Spiders

With the exception of two small groups, all spiders possess poison glands connected to their fangs. Fortunately, the fangs of most species are too short or fragile to penetrate the skin. Nevertheless two species of spider in Malta have been noted to be potential problems to humans. One species - the Beady Spider Steatodo paykulliana - has been cited as being poisonous to humans, but there have been no cases reported of such bites occurring in the Maltese Islands.

A case of a spider bite poisoning by the Recluse Spider Loxosceles rufescens has been reported. [Reference: D. Dandria, P. Mahoney: First record of spider poisoning in the Maltese Islands. Central Mediterranean Naturalist, 2002, 3(4):p.173-175: Clinical features of locally described case: The victim initially experienced a sudden sharp stinging pain which was followed by localized tenderness. A number of hours later the pain increased and the bite region became indurated and were associated with regional lymph node enlargement. This was associated with systemic symptoms of chills, malaise, diffuse muscle pain, low grade fever and nausea. The bite area developed a ~3 mm haematomatous lesion surrounded by a ~6 cm area of induration, together with inflammation of the lymphatic vessels leading to the regional lymph nodes. In spite of the treatment given, the local symptomatology persisted and increased to eventually cause necrosis of the skin and subcutaneous tissue. Clinical management: included the administration of a systemic steroid injection together with the oral administration of an antihistaminic and a broad-spectrum antibiotic. Surgical excision of the devitalized tissue in the area was eventually necessary.].

The increasing interest of keeping arachnids as pets may pose some further risk through the introduction of exotic species, e.g. Aphonopelma sp. [Tarantulas]. Tarantula venom contains a number of proteins, one of which has a cardiovascular effect though it is highly unlikely that the bite of one tarantula would produce a deleterious cardiac response in a human.


Clinical Features:

  • SCORPION STING: The first symptoms of a scorpion sting are that of a severe, sharp and burning pain, similar to a bee sting. The area can become swollen and discolored. It may form a blister. The region may experience some paraestesia with minimal swelling, some lymphangitis with regional lymph node swelling and an increase in skin temperature and tenderness around the wound. The symptoms usually last for eight to twelve hours. Scorpion toxicity is dose-related, and thus symptomatology can be more marked in young children. A hypersensitivity reaction is possible but unlikely.
  • SPIDER BITE: The bite of the Recluse Spider Loxosceles rufescens causes little pain initially, but within two to eight hours the pain will become severe and the area of the bite will become reddened. The venom contains a substance that is very destructive to tissue and causes a large spreading sore that eventually turns into a blister, becoming dark and hard within four days. The lesion has the appearance of a "bull's eye". Within two weeks, it forms an open ulcer that can become secondarily infected. The bite can also cause a range of systemic reactions including fever, chills, weakness, nausea, vomiting, joint pains and sometimes a generalized rash or reddish spots. Although the venom does not necessarily kill, death can occur within the first 48 hours as a result of renal failure caused by blood coagulation disorders leading to hemolysis and thrombocytopenia.
Treatment:
  • The treatment of scorpion poisoning is largely empirical. Cool compresses should be applied to the site. Analgesics can be given if required. Antihistaminics and corticosteroids are of little value.
  • The management of the Recluse Spider Loxosceles rufescens bite poisoning should include the administration of phentolamine to head off swelling and necrosis. Inject dexamethasone 4 mg i/m and 4 mg intradermally at the site of the bite. Repeat the local administration after 4 hours if the area of discoloration continues to increase in size; and repeat after 24 hours if systemic symptoms persist. Antihistamines, and muscle relaxants may provide some relief. Immediate excision of the bite area may be the only way to prevent massive tissue necrosis. 
    • Ulcerating lesions should be cleansed daily with peroxide; soaked in 1:20 Burow's solution three times daily; painted three times weekly with an aqueous triple dye mixture [1:400 gentian violet; 1:400 brilliant green; 1:1000 acriflavine]. A 5% scarlet red ointment or polymyxin-bacitracin-neomycin ointment can be applied at bedtime. Oxygen applied several times per day to the wound site can be of some value.
    • The onset of intravascular hemolysis can be detected early by determining hemoglobin and hematocrit every six hours for the first 48 hours and monitoring renal function. Any hemolytic reaction must be managed by attempting to maintain renal function with a urine output of 200 ml/hour by giving 4-8 liters of fluid daily [orally or i/v]. Furosemide 20-80 mg orally or intravenously may be given every 4-8 hours. Urine is kept alkaline by administering 1-2 gm of sodium bicarbonate every 4 hours. Mannitol administration may be necessary to maintain urine output. Exchange transfusion may become necessary.


 

1