Nematode Infections: Ascaris lumbricoides

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Questions and Answers

What is the typical somatic muscle arrangement found in Trichuris trichiura?

Polymyarian type

Heteromyarian type

Holomyrian type (correct)

Meromyarian type

What is the average number of eggs laid by a female Trichuris worm per day?

20,000 to 30,000

1,000 to 3,000

3,000 to 10,000 (correct)

10,000 to 20,000

What is the primary location where Trichuris trichiura larvae penetrate and stay for several days?

Intestinal villi (correct)

Peyer's patches

Mesenteric lymph nodes

Intestinal crypts

What is the approximate number of people affected by Trichuris trichiura infections worldwide?

1.2 billion Signup and view all the answers

What percentage of individuals infected with Ascaris lumbricoides are from Asia?

70% Signup and view all the answers

What is the duration of the hepato-tracheal migration of Ascaris lumbricoides?

14 days Signup and view all the answers

What is the primary protein used by Trichuris trichiura to embed into the intestinal wall?

TT47 protein Signup and view all the answers

What is the average number of eggs produced by a female Ascaris lumbricoides per day?

200,000 Signup and view all the answers

What is the typical size range of male Trichuris trichiura worms?

30 to 45 mm Signup and view all the answers

What is the characteristic arrangement of somatic muscles in Ascaris lumbricoides?

Polymyarian type Signup and view all the answers

What is the duration of development of egg-laying adults in Ascaris lumbricoides?

9-11 weeks Signup and view all the answers

What is the estimated number of disability-adjusted life years (DALYs) contributed by Ascaris lumbricoides?

1.85 million Signup and view all the answers

What is the primary mechanism of pathogenesis in Trichuriasis?

Worms embedded in mucosa cause petechial hemorrhages Signup and view all the answers

What is the name of the technique used to count the number of eggs in a stool sample?

Kato-Katz technique Signup and view all the answers

What is the recommended treatment for Trichuriasis in children?

Mebendazole 100 mg twice a day for 3 days Signup and view all the answers

What is the estimated global infection rate of Trichuriasis?

Approximately 604 to 816 million Signup and view all the answers

What is the recommended prevention and control strategy for Trichuriasis in communities with high prevalence?

Biannual mass drug administration Signup and view all the answers

What is the age group most frequently infected with Trichuriasis?

Children aged 5 to 15 Signup and view all the answers

Study Notes

Common Complaints and Infections

Abdominal pain is a common symptom associated with intestinal nematode infections.
Moderate infections may lead to lactose intolerance and vitamin A malabsorption.
Heavy infections can result in bowel obstructions and intussusception.

Diagnosis Techniques

Diagnosis is conducted via various stool examination methods, including:
- Direct Fecal Smear (DFS)
- Kato Thick Smear
- Kato Katz Technique
- Formalin Ether/Ethyl Acetate Concentration Technique (FECT)
Sensitivity of diagnostic techniques varies, with DFS being less effective compared to Kato Thick Smear and Kato Katz, and all being less effective than FECT.

Treatment Options

Anthelmintic medications for treatment include:
- Albendazole
- Mebendazole
- Pyrantel pamoate

Epidemiology and Impact

Approximately 1.2 billion people globally are affected by intestinal nematode infections, resulting in about 2,000 annual deaths.
Children aged 5 to 15 years are especially vulnerable.
Prevalence can reach 80-90% in high-risk groups such as public elementary school children.
Key transmission factors include socioeconomic conditions: population density, agricultural involvement, illiteracy, poor sanitation, and lack of health education.

Trichuris trichiura (Whipworm)

A soil-transmitted helminth (STH) with somatic muscle arranged in a "holomyrian type."
Males size: 30-45 mm; females size: 35-50 mm.
Males have a coiled posterior end with one spicule; females have a blunt posterior end and can lay 3,000-10,000 eggs daily, totaling about 60 million eggs over two years.
Eggs measure 50-54 μm by 23 μm, consisting of a yellowish outer and transparent inner shell.
Larvae penetrate intestinal villi, residing there for 3-10 days before embedding in the intestine wall.

Ascaris lumbricoides (Giant Round Worm)

Primarily tropical, infecting around 1 billion individuals, with 70% of cases in Asia.
Pathology includes tissue reactions to larval invasion, intestinal irritation, and complications from heavy infections.
Influences diseases of poverty, including malnutrition and cognitive impairment.
Adult size: Males 10-31 cm; Females 22-35 cm, smooth with a whitish or pinkish appearance.
Adults live in the small intestine without attaching, while larvae resemble adults and undergo hepatotracheal migration.

Clinical Manifestations

Majority of cases are asymptomatic but contribute to significant disability-adjusted life years (DALYs).
Complications from ascariasis may include respiratory symptoms during lung migration and intestinal obstruction.
Symptoms such as diarrhea, abdominal pain, and rectal prolapse can arise from heavy infections.

Trichuris Dysentery Syndrome

Associated with chronic dysentery and rectal prolapse, leading to anemia ranging from 0.8 to 8.6 ml blood loss daily.
In children, can cause poor appetite, stunting, and cognitive development challenges.

Laboratory Diagnosis for Trichuriasis

Diagnosed with severe chronic infections if symptoms include frequent blood-streaked diarrhea and abdominal pain.
Diagnostic methods include:
- Direct fecal smear using saline
- Kato thick smear method
- Kato-Katz technique for egg counting
- Concentration techniques (acid-ether and formalin-ether/ethyl acetate)
FLOTAC technique shows higher sensitivity compared to Kato-Katz and other methods.

Treatment for Trichuriasis

Primary treatment includes Mebendazole (100 mg twice daily for three days), with Albendazole as an alternative.
Deworming benefits include improved children's development and nutritional status.

Prevention and Control Measures

Recommended biannual mass drug administration (Mebendazole 500 mg or Albendazole 400 mg) in communities with ≥50% STH prevalence.
Target additional high-risk groups: preschool children, women of childbearing age, pregnant and lactating women, and adults in high-risk occupations.
Annual treatment suggested in communities with lower prevalence.

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Description

Learn about Ascaris lumbricoides, a type of intestinal nematode that affects over 1 billion individuals worldwide, primarily in tropical regions. Discover the pathology, symptoms, and complications of this infection, as well as its impact on health and productivity.