Intestinal Parasites: Ascariasis and Whipworm Quiz

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Questions and Answers

What is the primary cause of malnutrition associated with intestinal ascariasis?

Genetic predisposition

Competition for food (correct)

Bacterial infection

Viral invasion

Which statement accurately describes the life cycle of Trichuris trichiura?

The eggs take one week to mature in soil.

The adult worm lives exclusively in the stomach.

The eggs undergo lung migration.

The worm attaches to the intestinal mucosa. (correct)

What is a common complication associated with heavy infection of Trichuris trichiura?

Asphyxia

Rectal prolapse (correct)

Pulmonary edema

Peritonitis

What medications are commonly used for the treatment of ascariasis and whipworm infections?

Mebendazole and Albendazole Signup and view all the answers

Which of the following is NOT a preventive measure for intestinal ascariasis?

Use of feces as fertilizer Signup and view all the answers

Which of the following soil-transmitted helminths is known to infect over 1 billion people?

Ascaris lumbricoides Signup and view all the answers

What is the primary mode of transmission for hookworms?

Active penetration of the skin by larvae Signup and view all the answers

In which region is the prevalence of soil-transmitted helminth infections the highest?

Sub-Saharan Africa Signup and view all the answers

Which factors are crucial for the transmission of soil-transmitted helminths?

Moisture and warm temperature Signup and view all the answers

Which soil-transmitted helminths are primarily transmitted through ingestion of eggs?

Ascaris lumbricoides and Trichuris trichiura Signup and view all the answers

What percentage of children in urban slums are estimated to be affected by soil-transmitted helminth infections?

68.7% Signup and view all the answers

How long does it take for eggs of roundworms and hookworms to mature in soil?

2 weeks Signup and view all the answers

Which of the following communities shows the highest prevalence of soil-transmitted helminths among schooling age children?

Orang Asli Signup and view all the answers

How do children most commonly become infected with soil-transmitted helminths?

By playing on contaminated surfaces and putting hands in their mouths Signup and view all the answers

What is the main mode of transmission for larvae of hookworm and Strongyloides stercoralis?

Skin penetration through contaminated soil Signup and view all the answers

What does the term 'refractory to host immunity' imply in regards to soil-transmitted helminths?

They establish chronic infections despite immune responses Signup and view all the answers

What is the suggested frequency for treating high-risk groups for soil-transmitted helminthiasis?

Once or twice per year Signup and view all the answers

Which age group is noted to bear the greatest burden of soil-transmitted helminth infections?

Children between 5 and 14 years Signup and view all the answers

Why is there no established numerical threshold for disease caused by soil-transmitted helminths in children?

It depends on the child’s nutritional and immunological status Signup and view all the answers

What is a characteristic clinical manifestation of high-intensity soil-transmitted helminth infections?

General malaise and weakness affecting functioning Signup and view all the answers

In which specific occupations might adults be considered at high risk for soil-transmitted helminth infection?

Tea-pickers and miners Signup and view all the answers

What is the main reason deworming school-aged children is considered an economically efficient public health activity?

It addresses soil-transmitted helminths that affect child health. Signup and view all the answers

What is the consequence of heavy infection by Ascaris lumbricoides?

Nutritional deficiency and possible intestinal obstruction. Signup and view all the answers

How are embryonated eggs of Ascaris lumbricoides typically transmitted to humans?

Through the fecal-oral route from contaminated soil. Signup and view all the answers

Which of the following correctly describes the life cycle of Ascaris lumbricoides larvae after ingestion?

They penetrate the intestinal wall and migrate to the lungs. Signup and view all the answers

What type of eggs does a female Ascaris lumbricoides produce in the absence of males?

Infertile eggs. Signup and view all the answers

What causes Loeffler’s syndrome during the life cycle of Ascaris lumbricoides?

Sensitization during larvae migration through the lungs. Signup and view all the answers

What is a common laboratory method to diagnose ascariasis?

Identifying eggs in human feces. Signup and view all the answers

Which statement about the fertilized eggs of Ascaris lumbricoides is correct?

They become infective within two weeks in warm, moist soil. Signup and view all the answers

Study Notes

Soil Transmitted Helminthiasis (STH)

STH is a group of parasitic nematode worms
These infections are common in deprived communities worldwide
The worms thrive in warm, moist soil of tropical and subtropical regions
Transmission occurs via contact with parasite eggs or larvae
Infection is commonly co-endemic in areas with poverty and poor sanitation
Children are most commonly affected

Types of Soil-Transmitted Helminths

Nematodes (complete developmental stages in humans, require soil for transmission)
Ascaris lumbricoides
Trichuris trichiura
Hookworms: Necator americanus and Ancylostoma duodenale
Strongyloides stercoralis

Global Prevalence

Ascaris lumbricoides infects over 1 billion people
Trichuris trichiura infects 795 million people
Hookworms (Necator americanus and Ancylostoma duodenale) infect 740 million people
Highest numbers of infections in sub-Saharan Africa, the Americas, China, and East Asia

Mode of Transmission

Infections result from ingestion of eggs from contaminated soil
Transmission also happens through active penetration of the skin by larvae in soil
Soil-transmitted helminths usually need 2-3 weeks in soil to become infectious
People infected with STHs have parasite eggs in their faeces
Transmission happens in areas without latrines, contaminating soil and water.

Route of Infection (Oral Transmission)

Ascaris lumbricoides and Trichuris trichiura
Larvae ingest eggs from contaminated vegetables not cooked, washed or peeled.
Ingestion of eggs from water sources also possible.
Children playing on the ground, putting their hands in their mouths, are susceptible.

Route of Infection (Skin Penetration)

Hookworms and Strongyloides stercoralis
Eggs hatch into larvae in the soil
Transmission via larvae penetrating the skin, usually between toes.

Epidemiology

Climate is critical for transmission; adequate moisture and warm temperatures are crucial for larval development.
Poverty, inadequate water supplies, and poor sanitation are also significant factors.
Soil-transmitted helminth species are commonly co-endemic in areas with these conditions.

Prevalence in Different Communities

Prevalence data presented in percentages
Urban slum communities exhibit a high prevalence rate compared to other groups. (Details in the text)

Clinical Manifestation

STH infections are often asymptomatic (5-10 worms typically)
Heavy infections can lead to nutritional deficiency, abdominal pain, intestinal obstruction, and various complications
Lung migration of larvae can cause asthma, eosinophilia or other allergic reactions in severe instances

Host-parasite Interactions

Soil-transmitted helminths are resistant to host immune responses
Even with strong immune reactions, infections persist for life
Intensity of infection (e.g., hookworm) may increase with the host's age.
Worms may actively suppress the host's immune system

Control and Prevention

Control strategies focus on treating once or twice a year
Target groups include preschool and school-age children, women of childbearing age (including pregnant and lactating women), and adults at high risk (e.g., tea-pickers, miners).

Ascaris lumbricoides

Largest intestinal roundworm causing ascariasis
Adult female (20-35 cm), male (10-25 cm).
Fertilized egg is broadly oval (45-75 x 35-50 μm).
Thick shell, with brown bile-stained outer covering (albumin layer).

Ascaris lumbricoides Lifecycle

Ingested embryonated ova hatch in the small intestine.
Larvae penetrate intestinal wall and migrate to the liver, right heart, and lungs.
Larvae pass to the trachea and pharynx
Larvae swallowed, mature and mate in the small intestine.
Fertilized ova pass in feces to become infectious within 2 weeks

Trichuris trichiura

Also known as whipworm.
Long, slender, thread-like anterior portion, thicker posterior portion resembling a whip handle.
Adult worm (30-50 mm), male with a coiled tail and spicule
Oval (barrel-shaped), bile-stained eggs with thick shell and a clear polar plug at each end(45-55 μm × 20-23 μm)

Trichuris trichiura Lifecycle

Direct life cycle, after passage in feces
Eggs take 2 weeks to mature in soil
Ingested and develop in the large intestine.
No lung migration
Worm attaches to intestinal mucosa and takes 3 months for adult to lay eggs
Whipworm is globally distributed.

Other Notes

The report noted that the greatest burden of infectious diseases in children aged 5-14 in developing countries is caused by soil-transmitted helminth infections.
Deworming school-aged children is an economically efficient public health approach
Sanitation and personal hygiene are crucial for prevention
Avoid using feces as fertilizer
Common drugs for treatment include Mebendazole and Albendazole.
Standard lab methods for diagnosis including microscopy are used for feces samples.

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Description

Test your knowledge on intestinal parasites, specifically focusing on ascariasis and Trichuris trichiura. This quiz covers their life cycles, complications of infections, common medications for treatment, and preventive measures. See how well you understand these important topics in parasitology.