Parasitology

• Survival strategies of parasites include chronic infection and producing many eggs
• Symbiotic relationships can be parasitism (parasites benefit, hosts are harmed), commensalism (commensal benefits, hosts are unaffected), mutualism (both organisms benefit), predation (predator hunts prey), and competition
• Types of parasites include ectoparasites (live on the host's surface) and endoparasites (live inside the host's body)
• Endoparasites can be coelozoic (live inside the lumen of hollow organs like the intestine), histozoic (live in tissues), or cytozoic (live within cells)
• Parasites can have simple life cycles (one host) or complicated life cycles (two or more hosts)
• In complicated life cycles, there are definitive hosts (harbor adult stage) and intermediate hosts (harbor larval stage)
• Modes of transmission for parasites include fecal-oral route, foodborne transmission, arthropod-borne transmission, waterborne transmission, transmission through domesticated animals, skin penetration, sexual contact, and autoinfection
• Clinical implications of parasites include deprivation of nutrients, anemia, and various health issues like pruritus ani, dermatitis, mutilation of face, hepatosplenomegaly, blindness, and pneumonitis
• Parasitic infections can lead to conditions like anemia, macrocytic anemia, chronic infections, neglected tropical diseases, pruritus ani, dermatitis, mutilation of face, hepatosplenomegaly, blindness, and pneumonitis
• Parasites can cause high eosinophils and high IgE levels in the body
• Types of parasites based on parasitic activity include obligate parasites
• Parasites can cause chronic infections and are considered neglected tropical diseases in countries with high population density and poor hygiene
• Pruritus ani is associated with Enterobius vermicularis, causing itchiness of the anus, especially in children
• Dermatitis can be caused by parasites like Schistosoma spp. and hookworms
• Mutilation of the face can occur due to severe permanent disfigurement caused by parasites like Leishmania spp.
• Hepatosplenomegaly, enlargement of the liver and spleen, can be caused by parasites like Leishmania donovani
• Blindness can be a consequence of parasitic infections like Toxoplasma gondii
• Pneumonitis, characterized by cough and cold symptoms, can be caused by parasites like Ascaris and hookworms
• Diphyllobothrium latum uses paratenic hosts

  
• The adult worms of diphyllobothriid tapeworms live in the small intestine of the definitive host
• The eggs of diphyllobothriid tapeworms are passed in the feces of the definitive host and must be ingested by a crustacean to continue the life cycle
• Capillaria philippinensis can cause intestinal malabsorption in humans by covering the surface of microvilli in the intestine

  
• Strongyloides stercoralis can cause hyperinfection syndrome and has rhabditiform larvae in feces
• Loeffler’s syndrome is pneumonitis caused by Ascaris, while Wakana syndrome is pneumonitis caused by hookworm
• Rectal prolapse can be caused by trichuris infection
• Cutaneous larva migrans, or creeping eruption, is caused by Ancylostoma braziliense and Ancyclostoma caninum
• Visceral larva migrans and ocular granuloma are caused by Toxocara cati and Toxocara canis
• Hookworm and Strongyloides stercoralis have different larval stages: rhabditiform is the feeding stage and filariform is the non-feeding stage
• Filarial worms include Wuchereria bancrofti, Brugia malayi, Loa loa, Onchocerca volvulus, Dirofilaria immitis, and Dracunculus medinensis
• Bancroft’s filaria (Wuchereria bancrofti) causes elephantiasis and is sheathed, transmitted by mosquitoes, and nocturnal
• African eye worm (Loa loa) is sheathed, transmitted by flies, lives in subcutaneous tissue, and is diurnal
• Blinding filaria (Onchocerca volvulus) is unsheathed, transmitted by black flies, causes river blindness, and is non-periodic
• Guinea worm (Dracunculus medinensis) causes skin blisters and is transmitted by cyclops, with adults lying in the lymphatic system
• Dirofilaria immitis causes dog heartworm and is transmitted by mosquitoes
• Trematodes have suckers for attachment, are mollusk-transmitted, and have high specificity in snail hosts
• Schistosoma spp. have a complicated life cycle involving snails as intermediate hosts
• Schistosoma japonicum, Schistosoma mekongi, Schistosoma mansoni, and Schistosoma haematobium are different species of Schistosoma with varying geographical distributions and snail intermediate hosts
• Trematodes have oral and ventral suckers EXCEPT Heterophyes heterophyes which has additional suckers GONOCOTYL (genital sucker)
• Vitellaria found near intestine which synthesize protein material for the egg shell of fluke
• Trematodes are hermaphrodites except Schistosoma spp.. Instead, they have gynecophoral canal