Week 6 ,, Intestinal Nematodes

Nematode (Roundworm) Shape

Elongated cylindrical ,, Unsegmented

Nematode (Roundworm) Sexes

Separate

Nematode (Roundworm) Head End

No suckers ,, No hooks ,, Well developed buccal cavity

Nematode (Roundworm) Alimentary Canal

Present, complete anus

Nematode (Roundworm) Body Cavity

Present

What is Enterobius vermicularis also known as?

Pinworm

Who are the main host(s) of Enterobius vermicularis?

Humans

What is the diagnostic stage of Enterobius vermicularis?

Eggs on the perianal fold

What is the infective stage of Enterobius vermicularis?

When the embryonated eggs are ingested by humans

How and where do female Enterobius vermicularis lay eggs?

Females migrate outside the anus and lay their eggs while crawling on the skin of the perianal area

Enterobius vermicularis symptoms

Itchy ass

Lab Diagnosis of Enterobius vermicularis

Scotch tape test done in the morning ,, Anal swabs

What is Trichuris trichiura also known as?

Whipworm

Where does the ova of Trichuris trichiura mature?

In the enviorment

Adult Male Trichuris trichiura Morphology

Blunted posterior ends

Adult Female Trichuris trichiura Morphology

Long pointed tail

What is the diagnostic stage of Trichuris trichiura?

Unembryonated eggs passed in the feces

What is the infective stage of Trichuris trichiura?

When the embryonated eggs are in the soil and are ingested

Lab Diagnosis of Trichuris trichiura (Endoscopy)

Shows adult worms attached to the bowel mucosa

Laboratory Diagnosis of Trichuris trichiura (Microscopy)

Stool smear for ova and parasites ,, Formalin ethyl acetate sedimentation (FAS) technique is recommended for concentration for light infections

How is Ascaris lumbricoides spread?

Through contaminated soil and vegetation

What is the diagnostic stage of Ascaris lumbricoides?

Fertilized egg, unfertilized egg, and adult worm

What is the infective stage of Ascaris lumbricoides?

The fertilized eggs

Laboratory Diagnosis of Ascaris lumbricoides

Microscopic identification of eggs in the stool ,, Direct wet mount of specimen ,, Larvae in the sputum or gastric aspirate

What is Strongyloides stercolaris also known as?

Threadworm

What is the diagnostic stage of Strongyloides stercolaris?

Rhabdiitiform larvae in the intestine are excreted in the stool

What is the infective stage of Strongyloides stercolaris (1)?

Infective filariform larvae penetrate the intact skin, initiating the infection

What is the infective stage of Strongyloides stercolaris (2)?

The filariform larvae enter the circulatory system, are transported to the lungs, and penetrate the alveolar spaces ,, they are carried to the trachea and the pharynx, before being swallowed and reach the small intestine, where they become adults

What is autoinfection in Strongyloides stercolaris?

When the larvae become filariform larvae, penetrate the intestinal mucosa/parianal skin, and follow the normal infective cycle

Where does reproduction occur for Strongyloides stercolaris?

In the natural environment and its host

Loeffler Syndrome

Transient respiratory illness associated with blood eosinophilia and radiographic shadowing ,, occurs when the larvae migrate through the host’s lungs ,, Strongyloides stercolaris and Ascaris lumbricoides

Disseminated strongloidiasis

Involves widespread dissemination of larvae to the extraintestinal organs, which are outside the realm of the parasite’s ordinary life ,, all organs and tissues may be invaded

Lab Diagnosis of Strongyloides stercolaris

Stool or duodenal fluid ,, Antibody detection in serum ,, Larva currens (itchy, cutaneous condition)

Infectious Agent of Hookworm

Necator americanus and Ancylostoma duodenale

What is the diagnostic stage of Hookworm?

Eggs in feces

What is the infective stage of Hookworm?

When the filariform larva penetrates the skin

Path of Hookworms

Skin penetration → Circulatory System → Lungs → Pulmonary alveoli → Pharynx → Stomach → Small intestines

Lab Diagnosis of Hookworms

Microscopic identification of eggs in stool ,, Found in tissues stained with hematoxylin and eosin stain

Clinical Symptoms of Hookworm

Iron deficiency anemia ,, Cardiac complications ,, Respiratory symptoms ,, Gastrointestinal and nutritional/metabolic symptoms ,, “Ground itch” filariform larvae

What is the infective stage of Ancylostoma braziliense?

Third stage larvae

What is the diagnostic stage of Ancylostoma braziliense?

Eggs in the feces

Who are the host(s) of Ancylostoma braziliense?

Cats and dogs

Identify the causative agent

Enterobius vermicularis

Identify the causative agent

Enterobius vermicularis

Identify the causative agent

Enterobius vermicularis

Identify the causative agent

Enterobius vermicularis

Identify the causative agent

Trichuris trichiura

Identify the causative agent

Trichuris trichiura

Identify the causative agent

Trichuris trichiura

Identify the causative agent

Female Trichuris trichiura

Identify the causative agent

Male Trichuris trichiura

Identify the causative agent

Female Trichuris trichiura

Identify the causative agent

Male Trichuris trichiura

Identify the causative agent

Unfertilized Ascaris lumbricoides

Identify the causative agent

Unfertilized Ascaris lumbricoides

Identify the causative agent

Fertilized Ascaris lumbricoides

Identify the causative agent

Adult Ascaris lumbricoides

Identify the causative agent

Adult Hookworm

Identify the causative agent

Rabditiform larvae

Identify the causative agent

Hookworm