PARASITIC DISEASES (PD)

Parasitic diseases Protozoan Helminthic Malaria Amebiasis Giardiasis Toxoplasmosis Leishmaniasis Trypanosomiasi s Enterobiasis (pinworm) Cestodiasis (tapeworm) Ascariasis (roundworm) Trichuriasis (whipworm)

toxoplasmosis

Infection caused by protozoan parasite Toxoplasma gondii Primary or major host is cat of genus Felis domestica

toxoplasmosis …. Common route of infection in humans are: Ingestion of uncooked meat containing cysts Ingestion of vegetables contaminated with soil containing infective oocytes Consuming food or water contaminated with cat feces Transplacental fetal infection from acutely infected mothers Breast milk of infected mothers

clinical manifestations Congenital toxoplasmosis manifests as: Toxoplasmic encephalitis Chorioretinitis Convulsion Nephritis Hepatitis Pneumonitis Hydrocephalis Skin rashes

treatment Pyrimethamine plus Sulphadiazine Spiramycin x 3-4 wk alternatively Spiramycin During pregnancy and in the neonate x 3-4 wk

Parasitic Worms

Why it is important It is estimated that over 100 different types of parasitic worms can be found living in humans. Infection with helminthes or parasitic worms affects more than 2 million people worldwide. Infection is prevalent in rural tropics with high poverty rate where simultaneous infection with more than one worm is common.

Enterobiasis

Enterobiasis is an intestinal infection caused by the pinworm Enterobius vermicularis Pinworm is the most common helminthic infection

case L.C., a 6-year-old boy, is brought in by his mother, K.C., to see the family physician. K.C. states that L.C. was sent home from school because of inattention and disruptive behavior. L.C. has been very irritable and complained of abdominal discomfort and perianal pain on two occasions the previous week. A cellophane tape swab placed over the perianal skin demonstrates the translucent eggs of E. vermicularis. Question: Explain the symptoms observed in L.C. What pathologic changes are associated with enterobiasis?

Signs & symptoms Pinworm infection can be asymptomatic, but the most common symptom is intense pruritus and is caused by the sticky pinworm eggs in the perianal skin. Pruritus can cause constant scratching and can result in dermatitis and secondary bacterial infections. A heavy load of worms can cause anorexia, restlessness, and insomnia, resulting in behavioral changes

How should L.C. be treated?

Dose repeated in two weeks treatment Three different preparations are available to treat pinworm infection mebendazole albendazole pyrantel pamoate Single dose Dose repeated in two weeks

What advice should be given to L.C.’s mother?

Enterobiasis usually infects all members of a family when one member is infected Pinworm infection can recur as a result of reinfection within families Therefore, all household residents must be treated simultaneously

encourage careful hand washing and fingernail scrubbing after using the toilet and before meals K.C. needs to be reassured that pinworm infection in the home does not represent substandard hygiene

Cestodiasis

Cestodiasis (tapeworm infection) is caused by members of the phylum Platyhelminths (flat worms), which include, among others, Taenia solium(pork tapeworm), Taenia saginata(beef tapeworm), Diphyllobothrium latum (broad fish tapeworm), and Hymenolepis nana(dwarf tapeworm)

case B.R., a 10-year-old boy seen in the clinic complained of vague abdominal discomfort and pain. On questioning, B.R. reports seeing “white noodlelike” objects in his stools. Three stool samples over the course of several days demonstrate infection with T. saginata. IgE level and eosinophil count are within normal limits. Question: Are B.R.’s symptoms consistent with Taenia infection?

Patients with tapeworm infections (either T. saginata,as in B. R Patients with tapeworm infections (either T. saginata,as in B.R., or T. solium) present with symptoms ranging from mild epigastric or abdominal pain to a burning sensation, general weakness, weight loss, headache, constipation, and diarrhea. Complications from T. saginata include appendicitis, obstruction of pancreatic ducts, and intestinal obstruction.

How can T. saginata infection be differentiated from T. solium in B.R.?

The eggs of T. Saginata and T. Solium are identical presence of gravid proglottids or a scolex in the stool- helpful India ink test

How should B.R. be treated, and how should therapy be evaluated?

The drug of choice for both T. Saginata and T The drug of choice for both T. Saginata and T. Solium intestinal tapeworm infections is praziquantel 5 to 10 mg/kg as a single dose should be swallowed whole with a liquid with food If single dose not tolerated because of severe nausea and vomiting- divided doses 4 to 6hr interval

Eggs can be released when gravid segments of T Eggs can be released when gravid segments of T. solium disintegrate after treatment, and the release of embryos from the eggs can cause cysticercosis. To minimize this possibility, the clinician should give a purgative (magnesium sulfate 15–30 g) 2 hours after administration of praziquantel when T. solium infection is suspected