Hydatid Disease

HOSTS

Portal of Entry & Exit

• Definitive host- dog, wolf, fox, and jackel
• Intermediate host- sheep, pig, cattle, horse, goat, and humans

• Portal of Entry- Alimentary tract or digestive tract (water, food, flies, and fomites)
• Portal of Exit- Alimentary tract or digestive tract

Treatment

• Surgical removal of cysts. (may need chemotherapy to prevent recurrance)
• Chemotherapy
• PAIR treatment- Puncture, Aspiration, Injection, Respiration. Inject protoscolicidal substances into the cyst.

Resources

Prevention

• http://www.cdc.gov/parasites/echinococcosis/diagnosis.html
• http://web.stanford.edu/group/parasites/ParaSites2006/Echinococcus/main.html
• Google used for Images.

• Make yourself aware of the risks and proper safety precautions
• Abstain from feeding raw meat to dogs
• Enforce meat inspections
• Good hygiene
• Increasing access to diagnostic treatment and drug therapy, education, access to safe water, and improving sanitation and meat inspection.
• Deworming dogs, controlling stray dogs
• Vaccines are being developed for sheep in Australia,

Transmission

• Accidental ingestion of feces containing eggs by humans.
• Dogs ingest decomposing animal flesh containing cysts
• Soil, water, and food

Vectors

Hydatid Disease

Echinococcosis

• Bowflies
• Birds
• Arthropods as mechanical vectors of eggs

Signs & Symptoms

• CE- Asymptomatic until hydatid cysts containing larval parasites grow large enough to cause; pain, discomfort, nausea, and vomiting. Also depends on location of the cyst.
• AE- Discomfort, pain, weight loss, and malaise (uneasy, discomfort, illness)

Two Types:

• Echinococcus granulosus-Cystic echinococcosis (CE)
• Echinococcus multilocularis-Alveolar echinococcosis (AE)

Diagnosis

• Presence of a cyst-like mass in a person with a history of exposure to sheepdogs in an area of where Echinococcosis is present.
• Imaging techniques- CT scans, Ultrasound, and MRI's used to detect cyst.
• After detection- Serologic tests may be performed
• Serologic tests- Detect antibody response. •IHA (indirect hemagglutination test)
• •ELISA (enzyme-linked emmunosorbent assay)
• AE- Found in old people (same diagnostic procedures as above)

Life cycle of Hydatid disease

Hydatid Disease

• Hydatid tapeworm

• Parasitic Disease.
• Caused by infection from tapeworms of the genus Echinococcus.
• Either Cystic or Alveolar

Cyst in the brain

Cystic echinococcosis (CE)

Alveolar echinococcosis (AE)

Worldwide Importance

• Infection with the larval stage of Echinococcus granulosus.
• ~ 2-7 mm tapeworm.
• Cysts

Continued

• Disease caused by infection of the larval stage of Echinococcus multilocularis.
• ~ 1-4 mm long tapeworm.
• Disease in a human.

How do you become infected?

• Penetrates the intestinal wall & migrates through the circulatory system and to various organs
• Oncosphere develops into a cyst that enlarges gradually
• Produces protoscolices and daughter cysts that fill the cyst interior
• Difinitive host becomes infected by ingesting the cyst-containing organs of the infected intermediate host
• After ingestion, attatch to intestinal mucosa
• Develop into adult stages in 32-80 days

• Adult worm resides in small bowel of dogs or other hosts
• Proglottids release eggs & passed in feces
• Egg hatches in small bowel of intermediate host like a sheep

Reservoirs

• Cystic echinococcosis- E. granulosa : dogs, coyotes, wolves, sheep, pigs, deer, and wild herbivores.
• Alveolar echinococcosis- E. multilocularis : foxes, dogs, and wolves

Organs/Tissues affected

Unique Factors

• Eggs that have been deposited in the soil can stay viable for up to a year
• Most commonly found in people raising sheep

• Mainly found in- liver and lungs
• Spleen
• Kidneys
• Heart
• Bone
• Central Nervous System (brain & eyes)
• In CE- cyst rupture caused by trauma and causes mild to severe anaphylactic reactions and death are the result of released cystic fluid
• In AE- vesicles invade and destroy surrounding tissue.
• AE- causes liver failure and death