Generality
Black widow is the common name with which we want to indicate the female specimens of spiders belonging to the genus Latrodectus .
There are several species that are given the name of black widow, all united by some peculiarities:
- Black colour;
- Presence of spots on the abdomen, generally red, but different in shape, number and position;
- Hazard for humans in case of bite.
The black widow bite, in fact, can cause very serious symptoms and can lead to sometimes tragic consequences. Because of this danger, the black widow is considered in Italy - along with the violin spider - as a species of medical relevance to humans .
What is that
What is the Black Widow?
The name black widow is used to indicate the female specimens of spiders of different species but all belonging to the genus Latrodectus of the family Theridiidae .
The black widow is a cosmopolitan spider, therefore widespread throughout the world, including Europe and Italy. Each area of the planet is inhabited by certain species of black widow rather than others. For example:
- In North America, L. mactans and L. hesperus are particularly common, characterized by the presence of an hourglass-shaped red spot on the lower abdomen;
- In Central and South America, many species are widespread, including L. apicalis and L. mirabilis ;
- In Australia one can find L. hasselti and L. katipo
- In Asia, the species L. elegans and L. erythromelas are widespread;
- In central Africa and in Madagascar there are several species, including L. obscurior and L. menavodi ;
- In Europe, the Middle East and northern Africa, various species can be found, including L. pallidus, L. revivensis, L. hystrix and L. tredecimguttatus .
Usually, black widows have a body of variable length between 10 and 15 millimeters and are equipped with long legs.
Male specimens
The male specimens belonging to the genus Latrodectus, are also endowed with long legs but their body is generally smaller than that of the females (about 3-5 thousand meters). Also the coloring is different compared to the female specimens and can vary depending on the species to which it belongs (for example, black, brown, orange, etc.). Generally, the males are less or not at all poisonous and their eventual bite does not receive the same concerns as the black widow bite.
Did you know that ...
Some species of black widow, after mating, assume a cannibal behavior due to which they eat their "companion". It seems that the common name of black widow derives from this type of behavior.
Black Widow in Italy
In Italy, the black widow Latrodectus tredecimguttatus is widespread.
The name of this species derives from the fact that the female specimens have thirteen red spots on the abdomen.
L. tredecimguttatus is also known by the names of Mediterranean black widow, malmignatta, ragno volterrano or " di Volterra ". It is a spider that prefers warm climates and is particularly widespread in the Maremma, in Liguria, in Lazio, in the southern regions and on the islands. However, with the rise in global temperature, the presence of the "local" black widow cannot be excluded even in regions located further north, as long as the climate is favorable.
The Mediterranean black widow generally lives in the countryside, among stones, stones, weeds and, more often, near the wheat fields. In these places L. tredecimguttatus creates his lair weaving an extremely resistant canvas .
Curiosity
The canvas woven by the black widow was the subject of studies whose intent was to snatch the secret of its remarkable resistance. Indeed, it is believed that the fiber produced by the spider in question is comparable to steel in terms of applicable external force before causing it to break. The artificial reproduction of such resistant fibers could be useful in many fields, including industrial and military.
Bite
Black Widow Bite
The black widow bite is considered extremely dangerous as it can cause very serious symptoms with sometimes fatal consequences.
Generally, the black widow bite occurs as an accidental event if you come across the spider or its den, which can happen, for example, to farmers or other people who work in the places where it usually nests.
The black widow - although she tends to maintain a generally shy behavior - if disturbed, especially when inside her den, in many cases she tends to react by biting to defend herself.
Through the bite, the black widow can inoculate a powerful neurotoxic poison in humans, containing latrotoxins and other polypeptide toxins that are able to interact with the ionic channels of calcium, sodium and potassium causing the release of several neurotransmitters. This release leads to the typical symptomatology that occurs after the spider bites.
Did you know that ...
I saw her black, like any other spider, she uses her poison to immobilize and kill the prey she will eat. Since the human being is not seen by the spider as a prey, the bite to man is given only for defense. In fact, it is not unusual for the black widow to bite "dry", that is, without inoculating poison or otherwise inoculating an amount that would not be able to cause excessively serious consequences.
In this regard, however, it is worth pointing out that children, the elderly and debilitated adults are at greater risk of developing severe symptoms even when the spider injects small amounts of poison.
However, when introduced into the body through the bite, the poison spreads throughout the body through the lymphatic and blood circulation in a relatively short time.
The black widow bite itself is not excessively painful, as the spider chelicerae are not excessively large and robust. Intense pain and other severe symptoms are attributable to poison entering the circulation.
Symptoms and Latrodectism
Symptoms and Latrodectism induced by the Black Widow Bite
The symptoms induced by the black widow bite include both local symptoms and systemic symptoms . The set of morbid phenomena that arise as a result of poison inoculation is called latrodectism .
Local symptoms
In the area where the black widow has bitten, may appear:
- Acute toe pain;
- Edema;
- Erythema;
- Induration of the affected area;
- Flittene formation and, later, more or less extensive necrotic lesions appear.
Systemic symptoms
When the venom of the black widow spreads in the body, it can cause various systemic symptoms among which we remember:
- Headache;
- Nausea and vomit;
- Increased salivation;
- Sweating;
- Abdominal cramps;
- Muscle spasms;
- hyperventilation;
- Breathing difficulties and dyspnea;
- Agitation, restlessness and anxiety;
- Hypertension;
- Tachycardia or bradycardia;
- Tremors;
- Disseminated intravascular coagulation;
- Loss of consciousness.
In the days following the bite, pulmonary edema and bronchitis may also occur.
Complications
In some cases, the entry into the circulation of black widow venom could lead to the appearance of very severe complications, such as:
- tetany;
- Acute renal failure;
- Myocarditis;
- Rhabdomyolysis;
- Paralysis;
- Miscarriage.
In addition to the above, there is also the possibility that the wound caused by the bite becomes infected.
In allergic individuals, however, the black widow bite can lead to anaphylactic shock.
In the most serious cases and / or if it does not intervene promptly, the death of the individual may follow the coma.
Did you know that ...
Generally, the bite of the Mediterranean black widow appears to be less dangerous than that of the species spread in America. In fact, the cases of death caused by malmignatta bites are not as frequent as those of the species spread on the New Continent.
Care and Treatment
Care and Treatment of the Black Widow Bite
Fortunately, against the black widow poison a specific antidote that has significantly reduced the deaths caused by the attack of this spider against man.
If you are bitten by a black widow, it is therefore necessary to immediately contact the medical help (call 118) or go to the nearest emergency room, where, if necessary, the antidote will be administered. In fact, before administering the antidote it is advisable to evaluate the patient 's poisoning degree, since a quantity of poison is not always inoculated that leads to the appearance of latrodectism and serious complications.
Generally, the level of poisoning is classified into three grades that differ in the clinical picture presented by the patient:
- First degree : the individual manifests localized pain in the area where the black widow has bitten, but the vital parameters are normal.
- Second degree : there is muscular pain in the area that is bitten by the spider that can also extend to the abdomen. There is also an increase in sweating, especially in the area affected by the bite.
- Third grade : serious systemic symptoms are present and the patient's vital parameters are altered.
In addition to the possible administration of the antidote, the patient who arrives in the emergency room will receive all the necessary treatments and supportive therapies, such as, for example, the administration of muscle relaxants against muscle spasms, of analgesic drugs to contain the pain or respiratory support with oxygen in case of breathing difficulties.
Did you know that ...
While awaiting the arrival of medical aid, or during the journey to the emergency room, it may be useful to apply an ice pack on the bite; in this way, pain and swelling should decrease.
Diagnosis
How is the Black Widow Bite diagnosed?
Clearly, the diagnosis is extremely simple if the patient declares to have had contact with the black widow (which is also easily recognizable by its appearance and the characteristic red spots on the abdomen). Also, since the black widow bite is painful, the patient is likely to realize the attack when the spider is still nearby.
If, on the other hand, the patient is unable to confirm the contact with the black widow, the diagnosis is extremely difficult, since the symptoms and complications caused by the advent of the poison could be confused with the symptoms induced by other pathologies. Laboratory analyzes are generally of little use.
Prevention
Prevention of Black Widow Bite
The black widow is a spider with fairly long-term habits, in fact, once its own lot is built, it is difficult to get away from it. Therefore, the encounter with this spider usually occurs accidentally in the places where it usually weaves its own web.
However, if by chance it is necessary to go - for example to work - in places where the black widow is notoriously widespread, in order to avoid accidental bites, it can be useful:
- Wear protective clothing (gloves, long socks or shoes that cover the ankle, etc.) when performing activities at risk that could favor the encounter with the spider in question;
- Be extremely careful when facing spider webs or spiders' burrows and when trying to remove them;
- Should the black widow be seen, avoid direct contact with the hands or other parts of the body. In these cases, it is always preferable to move away.
Black Widow and Tarantolism
Bite of Black Widow and bond with Tarantolism
Tarantolism is defined as a hysterical-type cultural syndrome characterized by the appearance of a series of symptoms, some of which are similar to those induced by the advent of the black widow's poison.
The term tarantolism appears to have originated in the province of Taranto around the fifteenth century, where its onset was attributed to the tarantula bite ( Lycosa tarantula ).
Today, however, we are aware of the fact that the bite of the aforementioned spider is rather harmless and not capable of giving rise to a serious symptomatology such as that which should characterize tarantolism. For this reason, given its spread in Southern Italy, it was assumed that what the locals called tarantolism could be the consequence of the bite of the black Mediterranean widow.
