GENERAL PARASITOLOGY (An introduction) LECTURE NOTES ON GENERAL PARASITOLOGY (An introduction) Dept of Parasitology, Fac. of Medicine Universitas Padjadjaran

Introduction to Medical Parasitology Definition of Medical Parasitology Conceptions related to medical parasitology Relationships between parasite and host The basic factors of transmission of parasitic diseases The preventive measures of parasitic diseases

What are Parasites This presentation was initially developed by Mary Dillenbeck, 3rd Year veterinary medical student at Texas A&M University.

WHO GETS PARASITES ?

Why Do Parasites Matter Disease and Death Zoonotic Potential Wealth Loss

Definition of Medical Parasitology Medical Parasitology Parasites Parasitic diseases Morphology Life Cycle Pathogenesis Diagnosis Treatment Transmission Prevention

Conceptions related to medical parasitology Symbiosis Parasite and type of parasites Host and common type of host Life cycle and type of life cycle

Symbiosis ------The relationship beween two living things (animals). Two living things live together and involve protection or other advantages to one or both partner. Commensalism Mutualism Parasitism*

Commensalism ------ Both partners are able to lead indepenent lives, but one may gain advantage from the association when they are together and least not damage to the other. Fig. A female pea crab in the mantle cavity of its mussel host. The crab does not damage the mussel and uses its shell purely for protection

Mutualism ------ An association which is beneficial to both living things. Fig. A selection of ciliates from the rumen. The rumen contains enormous numbers of ciliates that break down cellulose in the feed.

Parasitism ------ An association which is beneficial to one partner and harmful to the other partner. The former that is beneficial to is called parasite, the latter that is harmful to is called host. Human / Hookworm

Types of Parasites Ectoparasites Live on the outside or skin of the host Usually insects or arachnids (ticks, mites, or spiders) Endoparasites Parasites found within the body of the host Can be in blood, tissue, or gastro-intestinal tract Nematodes, Trematodes, Cestodes and Protozoa

Ecto- & Endoparasitism Ectoparasites live on, but not in their hosts (they can nevertheless cause severe illness). Ich a protozoan ectoparasite of the skin of a fish. Endoparasite live within the body and tissues of their hosts. Trypanosomes (which cause sleeping sickness) within the blood of an infected animal.

Infection & infestation Infectious diseases are caused by transmittable parasitic agents including bacteria, viruses, fungi, protozoa and a variety of metazoans commonly referred to as helminths or worms Infection usually implies replication of the agent resulting in a growing number of pathogens Infestation are characterized by a constant number of pathogens. Severity of disease often depends on infection dose.

Is a mosquito a parasite? The border between parasitism and micro-predation is blurry Parasites usually live in a very intimate relationship with their host depending on more than food from it The host is food source and more or less permanent habitat at the same time Many parasites show strict specificity for a single host

METHOD OF/PORT OF PARASITE ENTRY Mouth Skin penetration Insect bite Inhalation Transplacental (Congenital) Transmammary Sexual Blood Transfusion Tissue Transplantation

Hosts and life cycles The definitive host is by definition the one in which the parasite reproduces sexually Additional hosts are then designated intermediate hosts Host which actively transmit parasites to humans are often called vectors In paratenic or transport hosts no parasite development occurs Reservoir host are alternate animal host from which the parasite can be transmitted to humans (zoonosis) or domestic animals Accidental host, not suitable for parasite development, but severe disease might ensue nonetheless

Parasite life cycle Many animal parasites also have the potential to infect humans Pass out brochures for zoonotic parasites. This is the hookworm lifecycle. People can be infected through fecal-oral ingestion of the eggs and skin penetration of the larvae from the soil it is common to see the tracts of the migrating worms on extremities such as the hands and feet.

Life cycle and type of life cycle Life cycle : The whole process of parasite growing and developing. The direct life-cycle : Only one host (no intermediate host). The indirect life cycle : Life cycle with more than one host (intermediat host and final host).

To study the parasite life cycle, there is need to know : Source of infection (reservoir) Site/method of entry of parasite into the host Physical changes of parasite occurring inside the host

The knowledge on life cycle is needed in relation to : PARASITE LIFE CYCLE The knowledge on life cycle is needed in relation to : Treatment Prevention Control/eradication

PARASITE LIFE CYCLE Reproduction may occur two ways : Sexual Asexual In term of sexual organ, parasite may be : Hermaphrodite, or Sexually separate (male and female)

Parasite and the type of parasites Parasite: It is an animal that is dependent on another animal (host) for its survival. Type of parasites Protozoa Nematodes Parasites Helminths Trematodes Endo- Cestodes Arthropods ---------------- Ecto-

Endoparasite and ectoparasite ----A parasite which lives in or on the body of the host is called endoparasite (protozoa and heminthes) or ectoparasite (arthropods).

Host and type of host Host : An organism that harbors the parasite usually larger than the parasite. Intermediate host : The host harboring the larvae or asexual stage of parasite. Final host : The host harboring adult or sexual stage of parasite. Reservoir host : Animals harboring the same species of parasites as man. Potential sources of human infection.

Relationship (Effect) between parasite and host injure to Parasites harbour in Host (animal or human) to response immune produce Effects of the parasites on the host Effects of the host on the parasites

Effects of parasites on the host Depriving the host of essential substance Hookworm Suck blood Anemia Mechanical effects of parasites on the host Ascaris Perforate/Obstruction Toxic and allergy effect E.h Proteolytic enzyme Necrosis Parasite antigen Immune system e.g Anaphylaxix Immune response Allergy/ Hypersensitivity

Effects of the host on the parasites ----The host can produce certain degree resistance to parasites in human body or re-infection. The resistance (Immunity) is not very strong. In general, It don’t wipe out parasites completely, but may limit the number of parasites and establish balance with parasites. Innate immunity Acquired immunity

Innate immunity Barrier : Prevent parasites to invade in certain degree. Skin/Mucous membrance/Placenta. Acid in skin or stomach can cause damage of the parasites. Phagocytosis of phagocyte. ----Non-specific/effective against a wide range of parasitic infection/controlled by genetical factors. But not very strong!

Acquired immunity Mechanism : cellular and humoral immunity. Sterilizing immunity : Wipe out the parasites completely, meanwhile get a long-term specific resistance to re-infection. Rare! Non-sterilizing immunity : Wipe out most of the parasites, but not completely. Common! No parasite, no immunity!

The basic factor of transmission of parasitic diseases Parasitic diseases Infectious diseases Transmission The source of the infection The routes of transmission The susceptible host ----The combined effect of those factors determine the dipersibility and the prevalence of the parasites at a given time and place and regulate the incidence of the parasitic diseases in certain local population.

The source of the infection Patient : Persons who have parasites in their body and show clinical symptoms. Carrier : Persons who have parasites in their body, not show symptoms. Reservoir host : Animals that harbors the same species of parasites as man. Sometimes, the parasites in animals can transmit into human.

The routes of transmission I Congenital transmission : From mother to infant. Toxoplasmosis Contact transmission : Direct contact---Trichomonas vaginalis; Indirect contact---Ascaris lumbricodes Food transmission : The infectious stage of parasites contaminated food / The meat of the intermediate hosts containing infectious stage of parasites.

The routes of transmission II Water transmission : Drink or contact the water contaminated the infectious stage of parasites. Soil transmission : Contamintion of the soil by feces containing the certain stage of parasites and this stage can develop into stage. Arthropod transmission : Vectors of certain parasitic diseases.

The susceptible host ----In general, most people is the susceptible host (Why?). The parasite reaching a susceptible host must gain entrance and set up a favorable residence in order to complete its life cycle and cause the transmission of parasitic diseases.

The avenues of invasion Digestive tract : Most common avenue of entrance. (Food/ Water transmission) Skin : Infective larvae perforate skin and reach to body and establish infection. (soil/ water transmission) Blood : Bloodsucking insects containing infective parasites bite the skin and inject parasites into human blood. (Arthropod transmission---malaria).

The prevention measures of the parasitic diseases Controlling the source of the infection. ----Treatment of the patients, carriers and reservoir hosts. Intervention at the routes of transmission ----Managing feces and water resource,controlling or eliminating vectors and intermediate hosts. Protecting the susceptible hosts. ----Paying attention to personal hygiene, changing bad eating habit, taking medicine.

Diagnosing Parasite Infection Direct observation Blood antigen tests Direct blood smears Skin scraping Fecal exam Biopsy of tissues Pictures right to left hook worm egg on a fecal float, babesia on a blood smear, and sarcoptic mange on a skin scraping. If available bring in a heartworm or giardia test to show the students.

Terima kasih atas perhatiannya ...... April 2005