Parasitic Diseases Quiz
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Questions and Answers

What is the primary vector responsible for transmitting volvulus to humans?

  • Female blackfly (Simulium spp) (correct)
  • Female sandfly (Phlebotomus spp)
  • Female tsetse fly (Glossina spp)
  • Female mosquito (Anopheles spp)

    • Which type of onchocerciasis skin disease is characterized by large areas of wrinkled, thin, dry inelastic skin?

  • Acute papular onchodermatitis
  • Chronic papular onchodermatitis
  • Lichenified onchodermatitis
  • Onchocercal atrophy (correct)

    • In chronic papular onchodermatitis, which areas of the body are most commonly affected?

  • Chest and abdomen
  • Shoulders and buttocks (correct)
  • Forehead and scalp
  • Palms and soles

    • What distinguishes palpable onchocercal nodules (onchocercomas) in terms of their contents?

    <p>Each nodule can contain 2 to 4 adult worms (D)</p> Signup and view all the answers

    What skin feature is associated with onchocercal depigmentation?

    <p>Islands of normally pigmented skin (A)</p> Signup and view all the answers

    What causes pediculosis capitis?

    <p>Pediculus humanus capitis (A)</p> Signup and view all the answers

    Which method is NOT effective in treating pediculosis capitis?

    <p>Antibiotics (D)</p> Signup and view all the answers

    Where are nits most commonly found on the head?

    <p>In the retro auricular region (D)</p> Signup and view all the answers

    What is the main risk factor for contracting jiggers?

    <p>Living in tropical areas (C)</p> Signup and view all the answers

    Which of the following treatments is NOT used for cutaneous larva migrans?

    <p>Surgical removal of larvae (D)</p> Signup and view all the answers

    Which population is particularly susceptible to pediculosis capitis?

    <p>School-aged children (D)</p> Signup and view all the answers

    What symptom is commonly associated with jigger infestation?

    <p>Painful, round swellings (B)</p> Signup and view all the answers

    How long should hair not be washed after applying certain treatments for pediculosis capitis?

    <p>24 hours (C)</p> Signup and view all the answers

    Which hookworm larvae is primarily associated with cutaneous larva migrans?

    <p>Ancylostoma braziliense (D)</p> Signup and view all the answers

    What is a potential side effect of using Lindane for treating pediculosis capitis?

    <p>Neurotoxicity if abused (A)</p> Signup and view all the answers

    What is a common complication associated with jigger infestation?

    <p>Secondary bacterial infection (C)</p> Signup and view all the answers

    What is the primary clinical feature of pediculosis capitis?

    <p>Pruritic eruption on the scalp (C)</p> Signup and view all the answers

    Which statement about nits in schools is true?

    <p>Many schools ban children from returning if nits are present. (A)</p> Signup and view all the answers

    What is a distinguishing feature of onchocerciasis?

    <p>May lead to river blindness (D)</p> Signup and view all the answers

    What method is suggested for preventing jigger infestation?

    <p>Wearing shoes (A)</p> Signup and view all the answers

    Which of the following statements about cutaneous larva migrans is incorrect?

    <p>It commonly results in severe systemic infections. (C)</p> Signup and view all the answers

    What is the primary living environment of Pediculus humanus corporis?

    <p>In clothing seams (B)</p> Signup and view all the answers

    Which clinical feature is commonly associated with pediculosis corporis?

    <p>Copper-colored macules on the body (A)</p> Signup and view all the answers

    Which diagnostic approach differentiates pediculosis corporis from scabies?

    <p>Lice and nits found on clothing (B)</p> Signup and view all the answers

    What characterizes the blue-gray hemorrhagic macules in pediculosis pubis?

    <p>Resulting from altered blood pigments (B)</p> Signup and view all the answers

    What is a recommended therapy for pediculosis pubis?

    <p>Malathion lotion and Permethrin cream (C)</p> Signup and view all the answers

    Which statement about lice survival without a blood meal is correct?

    <p>Can survive for 1 month in clothing (A)</p> Signup and view all the answers

    What is the main mode of transmission for pediculosis pubis?

    <p>Close physical contact (A)</p> Signup and view all the answers

    What primary symptom do patients with pediculosis pubis usually identify?

    <p>Moving lice in pubic hair (B)</p> Signup and view all the answers

    What is one of the early clinical presentations of onchocerciasis?

    <p>Subcutaneous nodules (A)</p> Signup and view all the answers

    Which symptom is associated with late-stage onchocerciasis?

    <p>Scarring (A)</p> Signup and view all the answers

    What is the significance of identifying microfilariae in skin snips?

    <p>It helps in the confirmation of active infection (D)</p> Signup and view all the answers

    Which complication may arise from onchocerciasis eye disease?

    <p>Blindness (C)</p> Signup and view all the answers

    Which treatment is effective in killing microfilariae but not adult worms in onchocerciasis?

    <p>Oral ivermectin (A)</p> Signup and view all the answers

    Which prevention method is recommended to avoid onchocerciasis?

    <p>Use of insect repellents like DEET (D)</p> Signup and view all the answers

    What describes the general outlook for onchocerciasis in some regions?

    <p>It has been successfully eradicated in some countries. (A)</p> Signup and view all the answers

    Which statement about the treatment of onchocerciasis is correct?

    <p>Treatment aims to stop the progression of the disease. (B)</p> Signup and view all the answers

    What is the primary reason papular urticaria is more common in children than adults?

    <p>Desensitisation to insect bites has not yet developed in children. (C)</p> Signup and view all the answers

    Which of the following clinical features distinguishes papular urticaria?

    <p>Clusters of itchy red bumps with a central punctum. (B)</p> Signup and view all the answers

    What histopathological finding is characteristic of papular urticaria?

    <p>Extravasation of erythrocytes. (C)</p> Signup and view all the answers

    What complication can arise from scratching lesions of papular urticaria?

    <p>Secondary bacterial infection. (D)</p> Signup and view all the answers

    Which measure is NOT recommended to prevent papular urticaria?

    <p>Taking daily antihistamines. (C)</p> Signup and view all the answers

    What role do topical steroid creams play in the management of papular urticaria?

    <p>They are used as soon as itchy spots appear. (C)</p> Signup and view all the answers

    Which of the following statements about papular urticaria is incorrect?

    <p>It is only diagnosed through skin biopsy. (C)</p> Signup and view all the answers

    Which group of individuals may experience papular urticaria when exposed to new environments?

    <p>Adults, especially travelers to new environments. (A)</p> Signup and view all the answers

    Flashcards

    Pediculosis

    An ectoparasitosis caused by blood-sucking wingless insects called lice, affecting humans.

    Pediculosis Capitis

    The type of pediculosis caused by Pediculus humanus capitis, affecting the scalp and hair.

    Nits

    The eggs of lice, often found attached to the hair shaft.

    How Pediculosis Capitis Spreads

    The most common way Pediculosis Capitis spreads is through direct head-to-head contact or sharing combs or hats.

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    Treatment for Pediculosis Capitis

    Pyrethrins and permethrin are effective in killing both lice and nits.

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    Alternative Treatment for Pediculosis Capitis

    Malathion 0.5% lotion is highly effective but can irritate the eyes.

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    Another Treatment Option for Pediculosis Capitis

    Lindane (gamma benzene hexachloride) is commonly used, but its effectiveness is less consistent and it can pose neurotoxicity if misused.

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    Treating Nits

    Nits are difficult to eliminate and often require repeated treatments.

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    Common Locations of Pediculosis Capitis

    Pediculosis Capitis is often seen as an epidemic in kindergarten and school settings.

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    Onchocerciasis

    A parasitic disease caused by the filarial worm Onchocerca volvulus, transmitted through the bite of a blackfly.

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    Onchocercal skin disease

    Itchy skin rashes that appear in various forms, including papules, plaques, and depigmentation. The most common type of skin disease in onchocerciasis.

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    Oncocercoma

    Round, firm bumps containing adult worms that develop under the skin. They can grow to several centimeters in size and are typically found near bony prominences.

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    Onchocercal atrophy

    A severe form of skin disease in onchocerciasis where large areas of skin become thin, dry, and inelastic, resembling leopard skin.

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    Onchocercal depigmentation

    A form of skin disease in which areas of pigment loss occur, giving a 'leopard skin' appearance, often affecting the shins.

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    Pediculosis corporis (Body Lice)

    A parasitic infestation of the body involving tiny insects called lice that feed on blood and live in clothing. It primarily affects individuals with poor hygiene, especially homeless people.

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    Pathogenesis of Pediculosis Corporis

    The way body lice cause an infection. They take blood meals by descending to the skin and lay their eggs in the seams of clothing.

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    Clinical Features of Pediculosis Corporis

    The symptoms of body lice infestation. Itching is accompanied by red marks, fluid-filled bumps, and skin irritation due to scratching. Secondary infections leading to wounds and crusty skin are also common.

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    Diagnosis of Pediculosis Corporis

    How to identify body lice infestation. Look for the lice and their eggs (nits) in the seams of clothing. It is important to distinguish it from scabies, which affects hands and feet.

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    Therapy for Pediculosis Corporis

    Medications that kill lice and eggs used to treat Pediculosis Corporis. Disinfection of clothing and bedding is crucial, as lice can survive for a month without feeding.

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    Pediculosis Pubis (Pubic Lice)

    A parasitic infestation of the pubic area involving small, crab-like lice called Phthirus pubis, commonly known as 'crabs'. Transmitted through direct contact, like sexual contact.

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    Clinical Features of Pediculosis Pubis

    The symptoms of a pubic lice infestation. Visible lice and their eggs (nits) can be observed on the pubic hair, accompanied by intense itching. Bite marks can also appear as blue-gray spots.

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    Therapy for Pediculosis Pubis

    Medications used to treat pubic lice, such as malathion lotion and permethrin cream or shampoo. Malathion's effectiveness against re-infection for weeks is an added benefit.

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    Jiggers (Chigoe Fleas)

    Tiny parasitic insects that burrow into the skin, usually between toes, and lay eggs causing itchy, painful swellings.

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    Jigger Life Cycle

    Jiggers are a type of flea that burrows into the skin, typically between the toes, and lay eggs. The female burrows into the skin, while the male feeds and then leaves.

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    Cutaneous Larva Migrans (CLM)

    A parasitic skin infection caused by hookworm larvae, especially Ancylostoma braziliense.

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    CLM Transmission

    CLM is a skin infection caused by hookworm larvae. Humans are accidental hosts, so the larvae eventually die.

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    CLM Symptoms

    The most common symptom of Cutaneous Larva Migrans is a snake-like track, raised and red, that can be several centimeters long. It causes itching and can be painful.

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    CLM Treatment

    The treatment of CLM usually involves using antihelmintic medications, which kill the larvae. Other treatments include the use of cryotherapy or laser therapy. Secondary bacterial infections may require antibiotics.

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    Onchocerciasis (River Blindness)

    A chronic and progressive disease caused by the Onchocerca volvulus worm.

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    Onchocerciasis Symptoms

    Common symptoms of onchocerciasis include itchy skin, skin lesions, and eye damage. In severe cases, it can lead to blindness.

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    Onchocerciasis Eye Disease

    Inflammatory response in the eye caused by dying microfilariae. Characterized by itching, redness, pain, and sensitivity to light. Leads to blurred vision, night blindness, glaucoma, and even blindness.

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    Microfilariae

    Tiny worm larvae that live in the skin and can cause inflammation and itching. They are the stage of the Onchocerca volvulus worm that infects humans.

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    Sowda

    A common symptom of onchocerciasis characterized by intense itching and darkening of the skin, particularly on the limbs.

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    Skin Snips

    A method of diagnosing onchocerciasis by examining thin biopsies of skin for the presence of microfilariae.

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    Prevention of Onchocerciasis

    The primary method of preventing onchocerciasis, as there is currently no vaccine available. Strategies include avoiding blackfly bites, using insect repellents, and wearing protective clothing.

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    Papular urticaria

    A skin reaction characterized by itchy red bumps (papules) that often appear in clusters, typically on the legs, forearms, and face.

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    Cause of Papular urticaria

    The most common cause of papular urticaria is an allergic reaction to insect bites.

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    Punctum in Papular urticaria

    A characteristic feature of papular urticaria is the presence of a small central point (punctum) on each papule.

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    Resolution of Papular urticaria

    Papular urticaria usually clears up on its own with time as the body develops desensitization to the insect bites.

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    Complication of Papular urticaria

    Secondary bacterial infection due to scratching can lead to painful pus-filled sores (pustules) and scabs.

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    Diagnosing Papular urticaria

    The diagnosis of papular urticaria is usually made based on the characteristic appearance of the rash.

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    Preventing Papular urticaria

    Wearing protective clothing and using insect repellents can help prevent insect bites and the development of papular urticaria.

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    Treating Papular urticaria

    Topical steroid creams, antihistamine tablets, and antiseptic cream can help manage the symptoms of papular urticaria.

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    Study Notes

    Parasitic Infestations

    • Parasitic infestations include pediculosis, scabies, myiasis, tungiasis, cutaneous larva migrans, and onchocerciasis.

    Pediculosis

    • Pediculosis is an ectoparasitosis caused by blood-sucking, wingless insects (lice).

    • Human infestations are caused by Pediculus humanus capitis (head lice), Pediculus humanus corporis (body lice), and Phthirus pubis (pubic lice).

    • Pediculosis capitis is commonly found on the head and is also known as head lice.

    • Pediculosis corporis affects the body or clothes.

    • Pediculosis pubis is caused by Phthirus pubis and affects the pubic area.

    • Pediculosis Capitis is common in children.

    • It is spread by head-to-head contact and shared combs/hats.

    • Often seen in epidemics among school-age children.

    • Also common in homeless people.

    • Lice live on the scalp and suck blood.

    • They firmly attach their eggs (nits) to the hair shaft.

    • The head louse is about 3-4 mm long.

    • Clinical features in Pediculosis capitis include pruritic eruption on the back of the scalp and nape, excoriations, and secondary infections.

    • Hairs may become matted from repeated scratching.

    • Lice are sometimes identified when combing the hair.

    • Nits are commonly found in the retro-auricular region.

    • Look for nits on hair shafts and lice on the scalp to diagnose Pediculosis capitis.

    • Effective treatments for Pediculosis capitis include pyrethrins and synthetic permethrin (1% and 5% cream).

    • Malathion 0.5% lotion—an effective treatment but can irritate the eyes.

    • Lindane, or gammabenzene hexachloride, is widely used but has a high potential neurotoxicity.

    • Crotamiton (Eurax) is also a treatment option.

    • Nits are a continuing problem to manage.

    • Many schools ban children with nits.

    • If present, retreatment is reasonable a week or so later.

    • Combing with a fine-toothed comb aids in treatment.

    • Pediculosis corporis: Same pediculicides as for Pediculus humanus capitis can be used.

    • Lice can survive in clothing for a month without blood meals.

    • Disinfect clothing and bedding (boiling, hot ironing).

    • Pediculosis pubis: Found in the pubic region and hairy areas of the legs, abdomen, chest, axillae, and arms.

    • Spreading is through close physical contact.

    • Commonly transmitted through sexual contacts.

    • Lice and nits are present in the hair, with symptoms similar to that of body lice.

    • Patients often report moving lice in pubic hair often accompanying pruritus.

    • Nits are typically found on pubic hair but may sometimes be found elsewhere on the body.

    • Feeding sites on the body may become distinctive blue-gray hemorrhagic macules.

    • These macules, often called maculae cerulenne, are commonly found on the sides of the trunk and inner thighs.

    • Malathion lotion and permethrin cream/shampoo are the preferred treatment choices for Pediculosis pubis.

    • Malathion sticks well to the hair to help prevent re-infection.

    • Lindane lotion/shampoo is also effective.

    • Treatment application should be repeated a week later.

    Scabies

    • Scabies is a highly pruritic skin infestation caused by Sarcoptes scabiei var hominis.

    • It's a host-specific mite.

    • Prevalence higher in children and active individuals.

    • Spread occurs through direct contact with an infected person (not from inanimate objects).

    • Mites can survive outside a host for up to 3 days.

    • Mites burrow into the epidermis (top layer of skin) after prolonged contact with an infected individual.

    • The S. scabiei female mite burrows through the stratum corneum at the rate of about 2 mm per day.

    • The female lays 2 or 3 oval eggs daily and the life cycle of the mites lasts 30 days, all within the epidermis.

    • The mites feed on dissolved skin tissue.

    • The feces of the mites are left behind within the skin's layers and cause irritation.

    • On initial infestation, a delayed type IV hypersensitivity reaction occurs over 4–6 weeks.

    • Symptoms include intense pruritus or itching, sometimes worse at night.

    • Lesions appear differently in adults and infants.

    • Adults: Lesions typically appear on the wrists, interdigital web spaces of the hands, feet, axillae, elbows, waist, buttocks, and genitalia.

    • Infants and children: Lesions may appear on the face, scalp, neck, palms, and soles.

    • Primary lesions include small papules, vesicles, and burrows.

    • Burrow are pathognomonic for S. scabiei and are linear, slightly raised.

    • Treatment options include scabicidal agents, antipruritic medication(e.g. sedating antihistamine), and antimicrobial medication if a secondary infection is present.

    • Topically applied scabicidal agents are usually repeated after 7 days.

    • Permethrin 5% cream is often the preferred option for infants and children.

    • Lindane 1% lotion or cream, sulfur 6% in petrolatum, and crotamiton (Eurax) 10% cream or lotion are also used.

    • In some cases, an oral ivermectin treatment is given.

    Myiasis

    • Myiasis refers to infestation of body tissues by larvae (maggots).

    • Different types of myiasis include the following,

      • facultative/traumatic wound myiasis: Eggs of certain flies which have larvae in suppurating tissues.
      • obligate cutaneous myiasis: Creeping eruptions and furuncular myiasis.

    • Furuncular myiasis presents with boils or pustules that have a central punctum.

    • A serosanguinous (blood tinged) discharge accompanies such sores.

    • Rapid resolution occurs when larvae are removed.

    • Signs or symptoms may include rapid resolution following extraction, lymphangitis.

    • Creeping eruption presents as a line of red, slightly raised tortuous lines.

    • It may resemble cutaneous larva migrans infection.

    • Treatment of myiasis types depends on the specific form.

    Tungiasis

    • Tungiasis is a disease caused by the tunga penetrans flea.

    • The flea penetrates into the skin, resulting in a small, round, painful, and itching swelling.

    • Secondary bacterial infection is likely to happen if not carefully dealt with.

    • Prevention can occur by maintaining house and environment cleanliness and by wearing shoes.

    • Treatment includes mechanical removal of the flea with a pin, followed by antiseptic dressing.

    Cutaneous Larva Migrans

    • Cutaneous larva migrans (CLM) is a parasitic skin infection caused by hookworm larvae, most often in tropical and subtropical locations.

    • It is characterized by a snake-like or linear track that follows the larva's movement.

    • The track is often itchy and elevated.

    • It is common in areas with warm environments (tropical, subtropical) and often found in those who are close to animals, like farmers and gardeners.

    • The eruption arises where the larvae penetrate the skin.

    • The bites usually cause mild to intense itching followed by a non-specific eruption.

    • The rash is often snake-like stretching up to 3-4 cm from the penetrating site.

    • Usually a self-limiting infection, where humans are not the definitive host.

    • Thus, the larvae die in most cases, and lesions resolve within 4–8 weeks without treatment.

    • Treatment is not necessary in most cases, but if treated, helminthics like tiabendazole, mebendazole, albendazole, and ivermectin can be used.

    • Additional treatments include liquid nitrogen cryotherapy or carbon dioxide laser treatment, antihistamines, topical corticosteroids, and antibiotics if a secondary bacterial infection is present.

    Onchocerciasis

    • Onchocerciasis is a chronic, progressive skin, eye, and neurological disease.

    • It's caused by the filarial nematode Onchocerca volvulus.

    • Often called “river blindness.”

    • Initial infestations often happen in childhood, with little to no apparent symptoms for a varying length of time.

    • Neurologic manifestations are common in children.

    • The disease is transmitted to humans through the bite of a female blackfly (Simulium spp).

    • Characteristics of the skin disease include widespread, itchy, eczema-like rash that progresses into vesicles and pustules.

    • Chronic papular onchodermatitis presents as itchy plaques.

    • The characteristic presentations in Onchocerciasis include acute or chronic onchodermatitis (itchy, eczematous rash with macules and papules), subcutaneous nodules (oncocercoma), lymphadenopathy, and sowda (sever pruritus).

    • Later symptoms may include lizard skin—dry, scaly skin resembling ichthyosis, hanging groin—a sac of atrophic skin, scarring, atrophy, elephantiasis, and leopard skin (depigmentation in the skin).

    • Eye disease occurs when microfilariae in the cornea and back of the eye die, often resulting in inflammation and bleeding.

    • Early symptoms include itching, redness, pain, and photophobia.

    • Continued inflammation can cause keratitis, sclerosis, blurring of vision, night blindness, glaucoma, visual field loss, and eventually blindness.

    • Diagnoses are aided by identifying microfilariae in skin snips, a chain reaction, and seeing adult worms in excised nodules.

    • To confirm, blood or eye analysis can also be used.

    • Preventative measures are key to fighting the transmission through the bite of black fly.

    • Such measures include using insect repellents, wearing long-sleeved shirts, and pants.

    • Ivermectin (oral) kills microfilariae, but not adult worms.

    • It should be administered every three months.

    • Other potential treatments for the disease include suramin and moxidectin.

    Papular Urticaria

    • Papular urticaria is a papulovesicular reaction to insect bites, more common in children.

    • It's also known as persistent insect bite reaction.

    • Children get it more often due to a lack of desensitization to insect bites.

    • Adults can still get it, especially those traveling to new areas or environments.

    • A reaction develops a few months to years after the initial bite.

    • The initial bite is often unnoticed.

    • Papules are itchy red bumps present, often in clusters.

    • The bumps most often occur on the legs and other exposed areas like forearms and face.

    • They can range from 0.2 to 2 cm in diameter and have small central punctuate marks.

    • Crops of fluid-filled blisters are possible.

    • New lesions and new bites can sometimes trigger itching in others.

    • Complications can include infected insect bites leading to cellulitis and rarely bacteremia.

    • Scratching can also lead to secondary infections like impetigo.

    • Localised vasculitis is also a possible complication.

    • Papular urticaria is typically diagnosed clinically.

    • Biopsy results sometimes can help with the diagnosis.

    • Histological presentations include mild dermal oedema, erythrocyte extravasation, and eosinophils.

    • Vasculitic markers in tissue might occasionally be present.

    • Preventative measures include protective clothing, and insect repellents.

    • Insect repellents and avoiding insect bites is part of the treatment too.

    • Symptoms can sometimes be alleviated by topical steroid creams.

    • Antibiotic or antiseptic creams can also aid in treating the presence of secondary infections in the skin.

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    Parasitic Infestations PDF

    Description

    Test your knowledge on various parasitic diseases, their causes, symptoms, and treatments. This quiz covers topics like onchocerciasis, pediculosis capitis, and jiggers. Delve into the complexities of these infections and understand their effects on humans.

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