helminths Protozoa Mulicellular Specialized cells Unicellular Single cell for all function Round worms (Nematodes) cylindrical, unsegmented Flat worms 1-Trematodes: leaf-like, unsegmented. 2-Cestodes: tape-like, segmented Amoebae: move by psudobodia. Flagellates: move by flagella. Ciliates : move by cilia Apicomplexa (sporozoa) Tissue parasites Classification of Parasites

Nematodes General features : 1. Elongated worm, cylindrical, unsegmented and tapering at both ends. 2. Variable in size, measure <1 cm to about 100cm. 3. Sex separate and male is smaller than female

Location of Nematodes: Intestinal nematodes Tissue nematodes

Intestinal Nematodes

Common intestinal nematode infections: 1. Enterobius (Oxyuris) vermicularis (Pinworm,seatworm,threadworm) 2. Trichuris trichiura (whipworm) 3. Ascaris lumbricoides (roundworm) 4. Ancylostoma duodenale & Necator americanus (hookworms) 5. Strongyloides stercoralis 6. :

(Pin worm, seat worm, thread worm ( Found all over the world. adult in lumen of cecum and appendix from which adult female migrate to rectum. It can be seen by naked eye as white thread ± 1cm. Male is smaller than female ± 0.5cm, with coiled end. Enterobius vermicularis (Oxyuris )

LIFE CYCLE Enterobius vermicularis (Oxyuris )

Pathology Majority of infectiona are asymptomatic. Main clinical presentation pruritus ani perianal excoriation Ectopic enterobiasis occurs in female when invade valva and vagina result in valvovagintis Usually accompanied by insomnia, anorexia, loss of weight and concentration (Side effect) Enterobius vermicularis (Oxyuris )

Treatment ِِ Albandazole, Mebendazole for whole family Enterobius vermicularis (Oxyuris )

Ascaris lumbricoides (roundworm)

Ascaris adult Ascaris lumbricoides (roundworm)

The commonest human helminthes infection. Found in jejunum and upper part of ileum. Female ± 20 cm longer than male ± 10 cm Feed on semi digested food. Ascaris lumbricoides (roundworm)

Ascaris lumbricoides

LIFE CYCLE Ascaris lumbricoides (roundworm)

Ascaris egg (embryonated) Ascaris lumbricoides (roundworm)

Ascaris eggs Ascaris larva emerging from egg Ascaris egg (embryonated )

Pathology: 1-Adult worm : Light infection : asymptomatic. Heavy infection : intestinal obstruction Migrating adult : to bile duct -jaundice 2-Larvae: Loeffler`s syndrome Pneumonia, cough with bloody sputum Eosinophilia, urticaria Ascaris lumbricoides (roundworm)

Loeffler`s syndrome: Larvae in lung pnumonia,cough,bloody sputum Ascaris lumbricoides (roundworm)

Ascaris larva in lung

Diagnosis: -eggs in stool. -larvae in sputum. -adult may pass with stool. Ascaris lumbricoides (roundworm) Treatment: Albendazole, Mebendazole

Trichuris trichiura (Whipworm)

LIFE CYCLE Trichuris trichiura (Whipworm)

World wide,common in poor sanitation. It coexists with Ascaris because of similar requirement. Adult live in large intestine especially caecum and appendix – in heavy infection the whole length of large intestine affected. Male and female worm have narrow anterior portion penetrate the intestinal mucosa Trichuris trichiura (Whipworm)

Pathology light infection : asymptomatic heavy infection :abdominal pain,bloody diarrhea. Rectal prolapse in children is a common complication. -Diagnosis: egg in stool characterized by its barrel shape with mucoid plugs at each pole. Treatment :Albendazole. Trichuris trichiura (Whipworm)

Embryonated egg Unembryonated egg Infective stage Diagnostic stage Trichuris trichiura (Whipworm)

-Diagnosis: egg in stool characterized by its barrel shape with mucoid plugs at each pole. Treatment :Albendazole. Trichuris trichiura (Whipworm)

Hook worms Ancylostoma dudenale &Necator americanus

1- Buccal cavity with intestinal mucosa 2- B.cavity with teeth &cutting plates anemia

LIFE CYCLE Hook worms Ancylostoma dudenale &Necator americanus

A common cause of anemia. Found in small intestine mainly jejunum. Its buccal capsule (mouth) lined with hard hooks, triangular cutting plates and anticoagulant glands. Hook worms Ancylostoma dudenale &Necator americanus

pathology& clinical picture: - larvae: i-At the site of entry of larvae (ground itch). ii- Migration phase: cough with bloody sputum pneumonia, eosinophilia,urticaria. - Adult worm: low worm burden: no symptoms. Moderate to heavy burden: epigastric pain, vomiting,simulating duodenal ulcer, hemorrhagic enteritis. Hook worms Ancylostoma dudenale &Necator americanus

Protein loss: hypoproteinaemia edema. Anemia: due to withdrawal of blood by parasites and hemorrhage from punctured sites lead to sever anemia = microcytic hypochromic. Hook worms Ancylostoma dudenale &Necator americanus

Diagnosis: -Eggs in stools.; -occult blood (+) Hook worms Ancylostoma dudenale &Necator americanus Treatment: Albendazol, Mebendazole

Strongyloides stercoralis Widely distributed in tropical region worldwide. fetal opportunistic in immuno- compromised host. It is smallest pathogenic nematodes ± 2.5mm. adult live in mucous membrane of duodenum jejunum

Strongyloides stercoralis

LIFE CYCLE Strongyloides stercoralis

Pathology and clinical picture: 1-Cutaneous little reaction on penetration. sever dermatitis at perianal region in case of external autoinfection. 2- Migration :same as hook worms. 3- Intestinal: inflammation of upper intestinal mucosa, diarrhea, upper abdominal pain clicky in nature. Disseminated strongyloidiasis : in patient with immunodeficiency,uncontrolled diarrhea – granulomatus changes – necrosis--perforation-- peritonitis--death. Strongyloides stercoralis

Diagnosis: rhabditiform larvae diagnostic stage in: -Stool examination -Duodenal aspirate Treatment : Albandazole, Mebendazole Strongyloides stercoralis

TISSUE NEMATODES

COMMON TISSUE NEMATODE INFECTIONS Trichinella spiralis adults in small intestine larvae in tissues (mainly in muscles). Toxocara canis (dog roundworm) larvae in organs (liver brain eyes), causing visceral larva migrans Dracunculus medinensis (guinea worm) adult female in subcutaneous tissues Filarial worms

Trichinella spiralis

Trichinosis

Most prevalent in areas where domestic pigs are allowed to roam freely.

Trichinosis Pathology: Adults cause mild gastroenteritis. Larvae cause fever, myositis and multi-system involvement which may lead to death. Diagnosis: serology, muscle biopsy. Treatment: Albendazole or Mebendazole + corticosteroids

Trichinosis

Visceral larva migrans: Caused by Toxocara canis Mainly affects children who eat soil contaminated with emberyonated (infective) eggs of Toxocara canis. Larvae do not develop in humans but migrate continuously in viscera and encapsulate, causing tissue damage.

Toxocara canis

Pathology: Eosinophilia, hepatomegaly, retinitis. Diagnosis: serology, biopsy. Treatment: Albendazole

Dracunculus medinensis

Draunculiasis Adult female lives in subcutaneous tissues, causing a skin ulcer through which it protrudes its anterior end. Main pathology due to secondary bacterial infection and allergic reactions. Diagnosis: clinical picture. Treatment: surgical removal. Caused by Dracunculus medinensis

FILARIAL WORMS: (Adult worms + microfilariae) 1. Onchocerca volvulus: Adults in subcutaneous swellings Microfilariae : mainly in skin, eyes causing River blindness 2. Wuchereria bancrofti, Brugia malayi & B. timori: Lymphatic filariasis (adults in lymphatics, microfilariae in blood) 3. Loa loa: Adults in subcutaneous and subconjunctival tissues, causing Calabar swellings. Microfilariae in blood

FILARIALIASIS )

Loiasis

Onchocerciasis (river blindness) Pathology: Adults worms live in subcutaneous nodules. Main pathology caused by microfilariae in: Skin: dermatitis Lymph nodes: lymphadenopathy Eyes: blindness Diagnosis: skin snip to identify microfilariae. Treatment: Ivermectin

Ivermectin

LYMPHATIC FILARIASIS

Lymphatic Filariasis

LYMPHATIC FILARIASIS Mainly caused by Wuchereria bancrofti and Brugia malayi Pathology: Due to adult worm obstructing lymphatics. Acute: lymphadenitis lymphatic varices Chronic: lymphedema, hydrocele, chyluria.

LYMPHATIC FILARIASIS Diagnosis: detection of microfilariae in blood in early stages of the disease: Blood film, Knott ’ s method ( concentration of 1 ml of blood), best 10 pm to 2 am (nocturnal periodicity). Immunological tests: Treatment: diethylcarbamazine (DEC) or ivermectin

Loa loa

Loiasis Pathology: Adult worm continously migration in subcutaneous and subconjuntival tissues, causing Calabar swellings (allergic reactions) and conjunctivitis.

Loiasis Diagnosis: detection of microfilariae in blood film. Treatment: diethylcarbamazine (DEC) or ivermectin, surgical remonval.

NON-FILARIAL TISSUE NEMATODE INFECTIONS treatmentDiagnosisLocation in human Mode of transmission DiseaseNematode species Surgical extraction clinicalSubcutaneous, mainly in lower limbs Ingestion of infected cyclops in water Dracunculiasi s, Guinea worm disease Dracunculu s medinensis albendazole Serology, muscle biopsy Muscles, lungs brain ingestion larvae in under- cooked pork Trichinellosi s (trichinosis) Trichinella spiralis albendazole Serology, ELISA Abdominal organs and brain Ingestion of infective eggs in soil Visceral larva migrans Toxocara canis

MAJOR FILARIAL INFECTIONS OF HUMANS Lab. diagnosis vectorLocation of microfilaria Location of adult in humans Geographic distribution Disease species Blood film mosquitoes Blood (nocturnal periodicity) Lymphatic vessels Tropical and subtropical areas elephantiasisWuchereri a bancrofti Blood film mosquitoes Blood (nocturnal periodicity) Lymphatic vessels AsiaelephantiasisBrugia malayi Skin snipSimulium spp. (black fly) Skin, eyes, no periodicity Subcutaneous nodules Africa, Central and South America, Yemen Onchocerciasis (river blindness) Onchocerc a volvulus Blood film Chrysops spp. (deer fly) Blood (diurnal periodicity) Moving in subcutaneous tissues Central Africa loiasisLoa loa