Neglected Diseases

A 6-year-old child from a rural Ghana presents with painless, raspberry-like skin lesions on the legs and arms. The lesions started as small bumps and gradually enlarged. There are no systemic symptoms. What is the most likely diagnosis?

• Onchocerciasis

• Yaws

• Buruli Ulcer

• Cutaneous Leishmaniasis

Answer explanation

Yaws is caused by Treponema pallidum pertenue, a spirochete bacterium related to syphilis.

Early lesions appear as painless, papillomatous (raspberry-like) skin growths, which can ulcerate. If untreated, the disease can progress to bone and joint deformities.

Transmission: Skin-to-skin contact, especially in children playing together.

Treatment: A single dose of azithromycin is highly effective in curing yaws.

 Leprosy primarily affects the skin and is not considered a neurological disease.

• True

• False

Answer explanation

Leprosy is primarily a neurological disease that affects peripheral nerves, leading to sensory and motor impairments. This can cause complications such as claw hand, foot drop, and chronic ulcers.

A 42-year-old man from West Africa has gradual swelling of his right leg and recurrent fever with swollen lymph nodes. A blood test shows tiny, thread-like parasites. What is the most likely disease?

• Malaria

• Schistosomiasis

• Leprosy

• Lymphatic Filariasis

Answer explanation

• Lymphatic Filariasis is caused by worms (filariae) that block the lymphatic system, leading to leg swelling (lymphedema/elephantiasis).

• Transmitted by mosquitoes, with parasites (microfilariae) detected in blood samples taken at night.

• Malaria (A) is mosquito-borne but causes fever, not swelling.

• Schistosomiasis (B) comes from contaminated water and mainly affects the liver or bladder, not the lymphatics.

• Leprosy (C) affects skin & nerves, not the lymphatic system.

The Bacillus Calmette-Guérin (BCG) vaccine provides some protection against leprosy.

• True

• False

Answer explanation

The BCG vaccine offers partial protection against leprosy by boosting the immune response against Mycobacterium leprae. However, its effectiveness varies, and breakthrough infections can still occur. Some countries include BCG in leprosy control programs to help reduce cases.

A 35-year-old man from an endemic region presents with numb, hypopigmented skin patches and thickened peripheral nerves. He also has clawed fingers and a positive acid-fast bacilli test on a skin smear. What is the most likely diagnosis?

• Leprosy

• Cutaneous Tuberculosis

• Psoriasis

• Tinea Corporis (Ringworm)

Answer explanation

• Leprosy (Hansen’s disease) is caused by Mycobacterium leprae and primarily affects the skin and peripheral nerves, leading to numbness, nerve thickening, and deformities (e.g., claw hand, foot drop).

• Acid-fast bacilli on a skin smear confirm the diagnosis.

• Cutaneous Tuberculosis (B) can cause skin lesions but does not lead to nerve thickening or sensory loss.

• Psoriasis (C) causes scaly plaques, not numb patches with nerve involvement.

• Tinea Corporis (D) (Ringworm) is a fungal infection, leading to itchy, circular rashes, not nerve damage.

Which of the following is the most appropriate first-line treatment regimen for multibacillary (MB) leprosy, and what is the primary mechanism of action of clofazimine?

• Rifampicin + Clofazimine+ Linezolid

• Rifampicin + Clofazimine + Ethionamide

• Rifampicin + Dapsone + Minocycline

• Rifampicin + Clofazimine + Dapsone

Answer explanation

• Multibacillary (MB) leprosy requires multidrug therapy (MDT) to prevent resistance.

• The WHO-recommended regimen includes:

  • Rifampicin (bactericidal) → Inhibits RNA polymerase, preventing transcription.

  • Dapsone (bacteriostatic) → Inhibits dihydrofolate synthesis, blocking folic acid metabolism.

  • Clofazimine (bactericidal & anti-inflammatory) → combines into bacterial DNA, leading to ROS generation and membrane damage while reducing inflammation.

This patient, a 40-year-old man from a rural area, presents with a painful skin ulcer on his foot, from which a long, thin worm is emerging. He reports drinking from an unfiltered water source weeks ago. What neglected tropical disease does this patient most likely have? (Hint: This neglected disease was eradicated from Ghana in 2015).

• Loa loa (Loiasis/ African eye worm)

• Onchocerca volvulus (River blindness)

• Dracunculus medinensis (Guinea worm disease)

• Mycobacterium ulcerans (Buruli ulcer)

Answer explanation

• Guinea worm disease (Dracunculus medinensis) is caused by drinking contaminated water containing infected copepods.

• After maturing in the body, the worm emerges through a painful skin ulcer over several weeks.

• No drug treatment exists—removal involves slowly extracting the worm.

Why Not the Others?

• Loa loa → Causes migrating swellings, but worms don’t emerge through ulcers.

• Onchocerca volvulus → Leads to blindness and skin nodules, not worm extrusion.

• Buruli ulcer → A bacterial infection causing painless ulcers, not due to a worm.