Filariasis & Schstosomiasis

What is Nematodes?

It is roundworms and parasites

It has complete digestive tract (moth and anus)

What is Filarial worms?

Tissue-dwelling nematodes

How does Filarial worms are transmitted?

By mosquitoes and other biting flies

What is Lymphatic filariasis?

Adult works live in lymph nodes and lymphatic vessels

What is most important causative agent in Lymphatic filariasis?

Wuchereria bancrofti

What are the steps of W. Bancrofti life cycle?

1) Infected mosquito transfers Filarial larvae onto skin

2) Larvae penetrate bite wound

3) Larvae enter lymphatic vessels and become adults

4) Adult female release microfilarial larvae

5) Microfilarial larvae enter blood

6) Mosquito ingests microfilarial larvae

What are the s/s of Lymphatic filariasis?

• In endemic areas, asymptomatic

• Acute

• Chronic

Which stage manifestation of Lymphatic filariasis shows lymphedema, elephantiasis?

Chronic

Which manifestation shows chyluria? And what is chyluria?

Chronic

It is lymph passed in urine

Which manifestation of Lymphatic filariasis shows nocturnal wheezing, edematous inflammatory plaque on skin?

Acute

What are the diagnosis of Lymphatic filariasis?

• Clinical presentation & patient Hx

• Microscopy of blood smears (definitive)

• Immunodiagnostics - antigen detection

• Ultrasound - imaging of adult worms

What are the treatment of Lymphatic filariasis?

Diethylcarbamazine (DEC)

What are the prevention of Lymphatic filariasis?

• Avoid mosquito bites

• Mosquito control

• Mass administration of DEC

What is Onchocerciasis?

Adult worms live in SQ tissues (Humans are only host)

Also known as River blindness

What is causative agent of Onchocerciasis?

Onchocerca volvulus

Onchocerciasis cause _________ and ________ in endemic area.

Blindness

Skin disease

What are the steps of O. Volvulus life cycle?

1) Infected blackfly transfer infective Filarial larvae onto skin

2) Larvae enter bite wound (SQ nodules)

3) Larvae become adults

4) Adult female worms release microfilariae in skin & lymph

5) Blackfly ingests worm

What are the s/s of Onchocerciasis?

• SQ nodules - not palpable, no symptoms

• Skin disease - rash, itching, cracking, depigmentation, thinning

• Eye disease - progressive damage to cornea, retina, optic nerve

What are the diagnosis of Onchocerciasis?

• Clinical presentations & patient Hx

• Microscopy - skin snips or nodule biopsy

• Slit-lamp eye exam

• Ultrasound

What are the treatment of Onchocerciasis?

• Ivermectin (Microfilaricide)

• Doxycycline (Macrofilaricide)

What is Trematodes?

It is known as Flukes

Parasitic flatworms

Trematodes has ________ digestive tract

Incomplete - no anus

Trematodes are hermaphroditic, what does it mean?

Male and Female’s reproductive organs are co-existed

(Exception: Schistosome Trematodes)

What is Schistosome Trematodes?

AKA Blood flukes

Live in mesenteric venues/veins of small/large intestine

Live in the venous plexus of urinary bladder

How does Schistosome Trematodes impact host body?

Eggs transverse host tissue, remain in host tissues

Eggs also travels to Liver, CNS, lungs, etc.

What are 2 subtypes (subspecies) of Schistosomiasis?

1) Haematobium

2) Mansoni

Which subtype of Schistosomiasis is associated with urinary bladder?

Haematobium

Which subtype of Schistosomiasis is associated with Mesenteric blood vessels?

Mansoni

What is intermediate hosts in Schistosomiasis?

Particular snail species

How does human acquire Schistosomiasis?

Contact with freshwater with infectious cercarial larvae (from infected snails)

What are the steps of Schistosoma’s life cycle?

1) Egg enter water, hatch, release snail-infecting larvae

2) Parasites develops & asexual reproduced in snail

3) Cercariae - exist from snail

4) Cercariae penetrate skin and into circulation

5) Cercariae migrate and mature in liver

6) Adults form migrate to mesenteric/urinary bladder

What are the s/s of Schistosomiasis?

• Most are asymptomatic

• Severity depends on worm & host immune

What are 2 infection types of Schistosomiasis?

1) Acute infection

2) Chronic infection

What are significant features of Acute infection of Schistosomiasis?

• Cercarial dermatitis - itchy rash at entry site

• Katayama fever - fever, chills HA, myalgia, cough, diarrhea, hepatosplenomegaly

What are 3 types of Chronic infection of Schistosomiasis?

• Intestinal schistosomiasis - abd pain, poor appetite, diarrhea, ulcer, anemia, polyps

• Hepatic schistosomiasis - hepatosplenomegaly, liver fibrosis, portal hypertension, ascites, esophageal varices

• Urogenital schistosomiasis - dysuria, hematuria, bladder fibrosis, kidney damage

What is the treatment of Schistosomiasis?

praziquantel

What is prevention and control of Schistosomiasis?

• Avoid freshwater where schistosomiasis occurs

• Education

• Improved sanitation

• Mass drug treatment

• Snail control