Question

"Ringworm" a common infectious disease in man causing dry scaly lesions on skin and scalp, is caused by
A. bacteria
B. roundworms
C. filarial worms
D. fungi

Answer 1

Hint: To answer this question, let’s discuss the causative agents of ringworms.
To start with, let’s recall some common pathogens. Pathogens are disease-causing organisms. The common human pathogens are bacteria, fungi, worms, and protozoans. Viruses also cause several human diseases.

Complete answer:
Bacteria are the prokaryotic pathogens that cause several human diseases such as tuberculosis, typhoid, and food poisoning. Roundworms are mostly pathogenic and exhibit distinct adaptations for their parasitic life. The most common example is Ascaris, a causative agent of ascariasis. The filarial worms, Wuchereria species, cause elephantiasis or filariasis characterized mainly by swelling of lower limbs and genitals due to the buildup of lymph.
Now, let's discuss ringworms. Ringworms are skin infections, also called Cutaneous mycoses or tineas. To set the analogy, Cutaneous means skin. They are caused by three different genera of skin infecting fungi namely Epidermophyton, Microsporum, and Trichophyton. These fungi are transmitted from person to person or from pet animals to humans under the conditions of poor hygiene. Sharing of personal objects such as towels spread the infection. These fungi affect the hair of the skin or scalp. The infection is characterized by loss of hair, inflammation, nail discoloration and thickening, and scaling. Humid and warm conditions favor the growth of these fungi which is why they mostly affect the skin folds of the groin and digits.
For example, Tinea capitis (capitis= head) refers to the infection of scalp hair caused mainly by Trichophyton or Microsporum species. Tinea barbae (barbae= beard), an infection of beard hair is caused by Trichophyton species.

So, the correct answer is D. fungi

Note: Students must not get confused with the name of the disease. Ringworms are not caused by any worms. They are named because of the shape of the appearance of lesions on the skin. Since, direct content and fomites are the sources of transmission, these skin fungi are spread quickly from person to person.