Parasitology

1. Parasitology FA 3108 Maria Immaculata Iwo School of Pharmacy ITB

2. INTRODUCTION • Parasitic diseases continue to be a major public health problem all over the world with associated high degree of mortality, morbidity, and man-day loss. • WHO statistics put parasites as leading cause of death after HIV/AIDs and tuberculosis • One out of ten living persons suffer from one or more of seven major tropical diseases, of which five are parasitic in nature. • Out of 60 million deaths in world, more than 25% are accounted to parasites. • Parasites affect over half the world’s population and are a major cause of mortality in the developing country.

3. With increasing • population, • urbanization, • industrialization, • poor socio-economic conditions and • poor sanitation facilities in developing countries, • deforestation, • unplanned reforestation and climatic changes,  some diseases which were previously unrecognized, are emerging. • Ethnic eating habits, • poverty, • tourism to exotic areas and • environmental degradation •  have led to • emergence • of food-borne • parasitic infections

4. Five parasitic infections • Malaria • Trypanosomiasis • Leishmaniasis, • Schistosomiasis • Filariasis • A number of parasites are now world-wide in their distribution Presenting the greatest challenges in the developing country

5. Many infections once thought to be harmless, are now known to be life-threatening in immunocompromised individuals and those suffering from acquired immunodeficiency syndrome (AIDS). These include: • Toxoplasma gondii • Cryptosporidium parvum • Isospora belli • Microsporidia maria immaculata iwo, sf itb

6. Currently no vaccineagainst any parasitic infection, in human, is available • Parasite also have capacity to develop drug resistance • Vectors transmitting certain parasitic infections have developed insecticide resistance Therefore, parasitic infections present enormous challenges maria immaculata iwo, sf itb

7. This lecture will cover • Essential details of general parasitology • Description of various protozoa and helminths • Geographical distribution • Habitat • Morphology • Life cycle • Pathogenicity, (and Immunity) • Epidemiology • Laboratory diagnosis, • Treatment and prevention • Description of various virus maria immaculata iwo, sf itb

8. LITERATURE 1. Arora, D. R. and B. Arora, 2007, Medical Parasitology, 2nd ed., CBS Publ. & Distributor, New Dehli 2. Markell, E. K., M. Voge, and D. T. John, 1992, Medical Parasitology, 7th ed., WB Saunders Co., Philadelphia 3. Peters, W. & H. M. Gilles, A Colour Atlas of Tropical Medicine & Parasitology, 3rd. ed., Wolfe Medical Publ. Ltd, Netherlands maria immaculata iwo, sf itb

10. blood and Tissue parasite maria immaculata iwo, sf itb

15. Life cycle of Isospora belli

16. Binding Reverse transcription Fusion Integration Endocyto-sis Transcription Nuclear localization Uncoating Splicing Lysosome RNA export Maturation Assembly Genomic RNA Modification Budding mRNA Translation Replication of HIV

17. Lyfe cycle of DNA virus 1. Attachment (Adsorption) 8.Budding from nucleus and release of virus 2.Penetration (pinocytosis. etc) 7. Assembly of virus particles in nucleus 3.Uncoating and Transfer of DNA to nucleus Inhibition of viral DNA polymerase: Acyclovir, Foscarnet 6. Late translation of viral mRNA into structural proteins 4.Early transcription and translation of viral mRNA 5. Synthesis of viral DNA and late transcription of viral mRNA

18. The objective of this lecture Known the characteristic of parasitic infection is benefit for…  morphologic specific, important for diagnoses life cycle complex, need or need not other host, more then one host,  for completely elimination of the parasite Location treatment strategic E. histolytica: intestine (GIT), lung, liver, brain, etc A. lumbricoides : GIT, lung, reproductive organ, brain, Trypanomiasis  two biological stadium: - haemolymphatic & meningoencephalitic

19. The objective of this lecture Clinical symptoms - similar to organ system clinical symptom? - with or without clinical symptom - can be acute or chronic infections harmful effect of parasitic infection - pharmacologic and or immunologic effects cause by a burden of parasite inside our body, its existence (colic of Ascariasis, encephalitis of N. fowlery) its stadia morphologic (eggs of Shistosome spp., sucker of worm), toxin secreted, toxic metabolite, dead parasite (Filarial worm  Mazotti reaction, T. solium blindness), granulomma (E. histolytica); Lymphoma, abortion (Toxoplasmosis)

20.  Treatment : not only used antiparasitic drugs, but also agent to cure clinical manifestations.  Sanitation and hygienicity Leuchorrhea  T. vaginalis

21. Habits  eating habits back to nature: eating raw vegetables, undercooked meat, fish, rabbit, insect time to suck the blood Children  health education  Health condition (Immunity)  “healthy - clean” food Better prevent than cure maria immaculata iwo, sf itb

22. General parasitology maria immaculata iwo, sf itb

23. Parasitology is the area of biology concerned with the phenomenon of dependence of one living organism on another. • PARASITE A parasite is an organism that is entirely dependent on another organism, referred to as its host, for all or part of its life cycle and metabolic requirements. It is of two types: • Microparasite • Macroparasite maria immaculata iwo, sf itb

24. Microparasite It is small, unicellular and multiplies within its vertebrate host, often inside cells. Viruses, bacteria and protozoa are microparasites. • Macroparasite It is large, multicellular and has no direct reproduction within its vertebrate host. This category includes helminths. maria immaculata iwo, sf itb

25. On the basis of their location, parasites may also be divided into two types: • Ectoparasites • Endoparasites • Ectoparasites Organisms which live on the surface of the skin or temporarily invade the superficial tissues of the host (e.g. lice). The infection by these parasites is known an infestation. maria immaculata iwo, sf itb

26. Endoparasites  Organisms that live within the body of the host All protozoan and helminthic parasites of man are endoparasites. The invasion by endoparasites is known as infection. maria immaculata iwo, sf itb

27. On the basis of host, parasites are subdivided into the following types: Obligate parasites: Organisms that cannot exist without a host (e g. Taxoplasma gondii)  Facultative parasites: Organisms that under favourable circumstances may live either a parasitic or free-living existence (e.g. Naegleria fowleri, Acanthamoeba spp. and Balamuthia mandrillaris). maria immaculata iwo, sf itb

28. On the basis of host, parasites are subdivided into the following types: Obligate parasites: Organisms that cannot exist without a host (e g. Taxoplasma gondii)  Facultative parasites: Organisms that under favourable circumstances may live either a parasitic or free-living existence (e.g. Naegleria fowleri, Acanthamoeba spp.) maria immaculata iwo, sf itb

29. Accidental parasites: Organisms that attack an unusual host (e.g. Echinococcus granulosus in man). Aberrant parasites: Organisms that attack a host where they cannot live or develop further (e.g. Toxocara canis in man). Free-living: The term free-living describes the non-parasitic stages of existence which are lived independently of a host. e.g. hookworms have active free-living stages in the soil. maria immaculata iwo, sf itb

30. HOST • is defined as an organism which harbours the parasite and provides the nourishment and shelter to the latter. Definitive host This is the host in which sexual reproduction of the parasite takes place or in which the most highly developed form of a parasite occurs. When the most mature form is not obvious, the definitive host is the mammalian host. maria immaculata iwo, sf itb

31. intermediate host The host which alternates with the definitive host and in which the larval or asexual stages of a parasite are found. Some parasites require two intermediate hosts for completion of their life cycle Paratenic host A host in which larval stage of a parasite survives but does not develop further. It is often not a necessary part of the life cycle. Reservoir host A host which harbours the parasite and serves as an important source of infection to other susceptible hosts. Epidemiologically, reservoir host are important in the control of parasitic diseases

32. Zoonosis • This term is used to describe an animal infection that is naturally transmissible to humams either directly or indirectly via a vector. Examples of parasitic diseases that are zoonosis include: - Leishmaniasis, - South American trypanosomiasis, - rhodesiense trypanosomiasis. - japonicum schistosomiasis, - trichinosis, fascioliasis, - hydatid disease, and cryptosporidiosis maria immaculata iwo, sf itb

33. Vector • A vector is an agent, usually an insect, that transmits an infection from one human host to another. • The term mechanical vector is used to describe a vector which assists in the transfer of parasitic forms between hosts but is not essential in the life cycle of the parasite e.g. a housefly that transfers amoebic cysts from infected food that is eatenby humans. maria immaculata iwo, sf itb

34. HOST-PARASTTE RELATIONSHIPS • Symbiosis An association in which both host and parasite are so dependent upon each other that one can not live without the help of the other. • Commensalism An association in which only parasite derives benefit without causing any injury to the host. • Parasitism Parasitism is a relationship in which a parasite benefits and the host provides the benefit. The host gets nothing in return and always suffers from some injury. The degree of dependence of a parasite on its host varies

35. SOURCES OF INFECTION Parasitic infections originate from following sources: 1. Contaminated soil and water; Soil polluted with human excreta acts as a source of infection with - Ascaris lumbricoides, - Trichuris trichiura, - Ancylostoma duodenale, - Necator americanus and - Strongyloides stercoralis Before acquiring infectivity for man, eggs of these parasites undergo certain development in the soil.  These are known as soil transmitted helminths

36. SOURCES OF INFECTION • Water polluted with human excreta may contain viable cystsof • Entamoeba histolytica, • Giardia lamblia, • Balantidium coli, eggs of - Taenia solium, - Hymenolepis nana, and the infective cercarial stageof - Schistosoma haematobium, - S. mansoni - S. japonicurn.

37. SOURCES OF INFECTION 2. Freshwater fishes constitute the source of Diphylobothrium latum and Clonorchis sinensis. 3. Crab and crayfishes are the sources of Paragonimus westermani. 4. Raw or undercooked pork is the source of Trichinella spiralis, T. solium, Fasciola hepatica, T. saginata, and S. suihominis. 5. Raw or undercooked beef is the source of T. saginata, Toxoplasma gondii, and S. hominis.

38. SOURCES OF INFECTION 6. Watercress is the source of Fasciola hepatica. 7. Blood-sucking insects transmit Plasmodium spp., Wuchereria bancrofti, Brugia malayi, Onchocerca volvulus, T. brucei, T. cruzi, Leishmania spp. and Babesia spp. 8. Housefly (mechanical carrier) is the source of E. histolytica. 9. Dog is the source of Echinococcus granulosus and Toxocara canis (visceral larva migrans).

39. SOURCES OF INFECTION 10. Cat is the source of T. gondii, 11. Man is the source of E. histolytica, Enterobius vermicularis, and H. nana. 12. Autoinfection may occur with E. vermicularis and S. stercoralis, leading to hyperinfection, maria immaculata iwo, sf itb

40. PORTAL OF ENTRY INTO THE BODY 1. Mouth The commonest portal of entry of parasites is oral, through contaminated food, water, soiled fingers or fomites. • This mode of transmission is referred to as faecal-oral route. • e.g. • E. histolytica, G lamblia, B. coli. • E. vermicularis, T. trichiura, A. lumbricoides, • T. spiralis, T. solium, T. saginata, • D. latum, F. hepatica, C. sinensis • Fasciolopsis buski, P. westermani maria immaculata iwo, sf itb

41. PORTAL OF ENTRY INTO THE BODY 2. Skin • Infection with A. duodenale, N. americanus and S. stercolaris is acquired when filariform larvae of these nematodes penetrate the unbroken skin of an individual walking over faecally contaminated soil. • Schistosomiasis caused by S. haematabium, S. mansoniand S. japonicumis acquired when the cercarial larvae, in water, penetrate the skin. • A large number of parasites e.g, Plasmodium spp., W. bancrofti, B. malayi, O. volvulus, T. brucei, T. cruzi, Leishmania spp. and Babesia spp. are introduced percutaneoursly when blood-sucking arthropods puncture the skin lo feed.

42. PORTAL OF ENTRY INTO THE BODY 3. Sexual contact Trichomonas vaginalisis transmitted by sexual contact, E. histolyticaand G. lamblia may also be transmitted by anal-oral sexual practices among male homosexual 4. Kissing E. gingivalisis transmitted from person-to-person by kissing or from contaminated drinking utensils. 5. Congenital Infection with T. gondii and Plasmotiium spp. may be transmitted from mother to foetus transplacentally maria immaculata iwo, sf itb

43. PORTAL OF ENTRY INTO THE BODY 6. Inhalation Airborne eggs of E. vermicularis may be inhaled into posterior pharynx leading to infection. 7. latrogenic infection - Malaria parasites  transmitted by transfusion of blood from the donor with malaria containing asexual forms of erythrocytic schizogony  This is known as trophozoite-induced malaria or transfusion malaria. - Malaria parasites may also be transmitted by the use of contaminated syringes and needles  This may occur in drug addicts.

44. LIFE CYCLE OF HUMAN PARASITES • On the basis of their life cycles human parasites can he divided into three major groups: NO INTERMEDIATE HOST Protozoa Entamoeba histolytica G. lamblia Chilomastix mesnili T. vaginalis B. coli Helminths E. vermicularis T. trichiura Ascaris lumbricoides A. duodenale N. americanus H. nana

45. ONE INTERMEDIATE HOST

46. TWO INTERMEDIATE HOSTS maria immaculata iwo, sf itb

47. PATHOGENICITY • A parasite may live in or on the tissues of its host - without causing evident harm. - However, in majority of cases the parasite has the capacity to produce damage. • With the advent of AIDS, there is an increase in the incidence of newer parasitic infections caused by Cryptosporidium parvum, Isospora belli, and other hitherto unheard of parasites. • These parasites also cause infections in patients who are immunocompromised e.g, patients receiving cytotoxic drugs or organ transplant. maria immaculata iwo, sf itb

48. Damage may be produced by the parasites 1. Traumatic damage Relatively slight physical damage is produced by entry of - filariform larvae of S. stercoralis, A. duodenale and N. americanus and - cercarial larvae of the Schistosoma spp. into the skin.  Migration of several helminthic larvae through the lung produces traumatic damage of pulmonary capillaries leading to extravasation of blood into the lung.  Similar damage in cerebral, retinal or renal capillaries may lead to serious injury.  Eggs of S haematobium and S. mansoni cause extensive damage with haemorrhage as they escape from vesicle and mesenteric venules, respectively, into the lumen of the urinary bladder and the intestinal canal

49.  Attachment of hookworms(A. duodenale and N. americanus to the intestinal wall results in traumatic damage of the villi and oozing of blood at the site of attachment  Large worms, such as A. lumbricoides and T. saginata may produce intestinal obstruction.  Ascaris, in addition, may occlude lumen of the appendix or common bile duct, may cause perforation of the intestinal wall, or may penetrate into the parenchyma of the liver and the lungs. 2. Lytic necrosis E. histolytica secretes lytic enzyme which lyses tissues for its nutritional needs and helps it to penetrate into the tissue of the colon and extraintestinal viscera.  Obligate intracellular parasites e.g. Plasmodium spp., Leishmania spp., Trypanosoma cruzi and T. gondii cause necrosis of parasitized host cells during their growth and multiplication

50. 3. Inflammatory reaction • Most of the parasites provoke cellular proliferation and infiltration at the site of their location. • In many instances the host reaction walls off the parasite by fibrous encapsulation. • In metazoan and in some protozoan parasitoses, there is a moderate-to-notable eosinophilia. • Iron-deficiency, pernicious and haemolytic anaemia develop in patients with hookworm disease, diphyllobothriasis and malaria, particularly blackwater fever, respectively. • E. histolyticamay produce inflammation of the large intestine leading to the formation of amoebic granuloma or amoeboma. • Parasitization of fixed macrophages in the spleen, bone marrow, and lymph nodes by L. donovani causes proliferation of reticuloendothelial cells.