Scarabiasis

Key takeaways

Scarabiasis belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Scarabiasis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Scarabiasis from memory before moving on to harder problems.

Reference excerpt

Scarabiasis, or "beetle-disease", is a condition where beetles temporarily infest the digestive tract of other animals. It can also affect humans, and despite being a rare phenomenon, it is the second most important insectal disease in humans after myiasis, which is caused by the larva of flies. The term is commonly used as a synonym of canthariasis, but the latter refers to the infection of animal tissues by beetle larva, whereas the Scarabiasis refers to the infection by adult beetles. Moreover, Scarabiasis refers to the passing of live beetles in animal faeces. Reported symptoms of scarabiasis include loss of appetite, diarrhea, abdominal cramps, vomiting, nausea, and insects in stool. Scarabiasis has been known to infect the gastrointestinal tract, urogenital system, nasal sinuses, ears, and faces of mammals and other animals.

Agents Coleoptera constitutes the second most represented insect order in the infections of human organisms, only after Diptera. One of the known agents which can potentially infect humans is the beetle Tenebrio molitor, commonly known as “mealworm”, of the family Tenebrionidae. The life cycle of this organism comprises four stages including egg, larva, pupa and adult forms. The entire life cycle lasts approximately one year. Adult and the larvae feed on grains (hence the name mealworm), meat or decomposing animals including birds, spiders, rodents, lizards and some other beetles. They usually originate from damp, dark places, often in decaying cereals. Larvae of T. molitor are widely available as pet food for birds, fish, and reptiles, and they are growing their importance as food for humans, due to the fact that they are rich in proteins and they are traditionally consumed as food in many Asian countries. The insect is native to Europe, but it is now distributed worldwide. Despite being relatively popular, little is known about the mammalian parasitism of T. molitor. The worm is not obligate parasite of animals. The cigarette beetle, Lasioderma serricorne, is also reported to be an agent of Scarabiasis in humans. In 2016, the Department of Parasitology of the Sun Yat-sen University in Ghuanzhou, China, reported the first case of an eight-year-old baby girl infected by this beetle. The urinary system can very rarely be an accidental site of beetle larvae colonization, likely when eggs are laid by adults on the skin surrounding the urethral opening or the urethral meatus and their larvae ascend. Stiles and Hassal cite cases of coleopteran pseudoparasitism of the urinary tract reported for beetles of genus Balaninus, Curculio, Nitidula and Tenebrio.

Infection Given the limited number of records of scarabiasis occurrence in animals, the most frequent portal of entry of the agent in the host organism is still partially unknown. Some reported cases of scarabiasis in humans from the early 20th century were collected in rural India by Strickland and Roy, professors of medical entomology at the School of Tropical Sciences in Calcutta. The authors hypothesised two possible forms of entry in human organism, both equally probable. The first is the oral ingestion (per os) accidentally with food, when, for instance, young children eat food picked up from dirt or mud floors. The second one is through the anus (per anum). For example, as scarabiasis is more common in children, the time of entrance is possibly when children play outside naked, while they are sleeping, or while they are defecating. The authors speculated that the dung beetles could be attracted to the scent of human feces and crawl into the anus during defecation, but this theory was never confirmed. The more recent evidences described the oral ingestion as the most common way how the parasite entered the host. Infected humans usually host those organisms in the gastro-intestine tract, probably after ingesting it accidentally with contaminated or dirty food. Beetle larvae have been recovered, more rarely, from other human organs, such as tonsils, nose and urinary bladder, or the umbilical cord. Children are, in general. more susceptible hosts given their underdeveloped immune system. Moreover, canthariasis has been reported in a case with HIV/AIDS patients associated with skin ulcer. Ulcers in HIV patients and other diseases related to skin damages could increase susceptibility to a wide range of infections such as canthariasis. The beetles (or their larvae) which may cause canthariasis, can be intermediate hosts of other pathogens. For instance, Tenebrio molitor can be the intermediate hosts of the rat tapeworm, Hymenolepis diminuta. Only anecdotal infections by this organism were recorded in humans, and the large majority of the infected individuals were asymptomatic. However, abdominal pain, irritability, itching, and eosinophilia are among the existing symptoms in a few of the reported cases.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Scarabiasis

Start with the simplest possible case. Write down what Scarabiasis claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Scarabiasis before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Scarabiasis ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Scarabiasis

In research: Scarabiasis appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Scarabiasis in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Scarabiasis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arthropod infestations, so understanding it makes those chapters shorter.
In everyday life: Look for Scarabiasis outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Scarabiasis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Scarabiasis means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Scarabiasis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Scarabiasis in simple terms?

Scarabiasis, or "beetle-disease", is a condition where beetles temporarily infest the digestive tract of other animals. It can also affect humans, and despite being a rare phenomenon, it is the second most important insectal disease in humans after myiasis, which is caused by the larva of flies.

Why does Scarabiasis matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Scarabiasis?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Scarabiasis.