PARA311 Clinical Parasitology PDF - Week 2 Introduction

PARA311: CLINICAL PARASITOLOGY WEEK 2: INTRODUCTION TO PARASITOLOGY PERIOD: PRELIM, 3RD YEAR, A.Y. 2024-2025 PROFESSOR: ROSE DYANE HIZOLA, RMT, MPH and RICH KING T. VALDEZ, RMT PARASITOLOGY SOURCES OF EXPOSURE T...

PARA311: CLINICAL PARASITOLOGY WEEK 2: INTRODUCTION TO PARASITOLOGY PERIOD: PRELIM, 3RD YEAR, A.Y. 2024-2025 PROFESSOR: ROSE DYANE HIZOLA, RMT, MPH and RICH KING T. VALDEZ, RMT PARASITOLOGY SOURCES OF EXPOSURE TO INFECTION  An area of science, which deals with the study of organisms living  Pathogens: can be animal parasites that are harmful and frequently permanently or temporarily on or within another organism. cause mechanical injury to their host  The branch of biology or medicine concerned with the study of parasitic  Carrier: harbours a particular pathogen without manifesting signs and organisms. symptoms  It is the study of parasites, their hosts, and the relationship between  Exposure: process of inoculating an infective agent them.  Infection: establishment of the infective agent in the host  Concerned with the phenomena of dependence of one living organism  Incubation period: period between infection and evidence of on another. symptoms Divisions Of Parasitology  Pre-patent period: biological incubation period, period between Protozoology infection and acquisition of the parasite and evidence or demonstration  Protozoans: small, unicellular organisms, which contain nucleus and of infection. functional organelles.  Autoinfection: infected individual becomes his own direct source of Helminthology infection  Worms: larger, multicellular organisms, normally visible to the naked  Superinfection or Hyperinfection: already affected individual is eye in their adult form. further infected with the same species leading to the massive infection Medical Entomology with the parasite  Insects and arthropods  Co-infection: simultaneous infection of a host by two or more parasite Sources Of Exposure To Infection TERMINOLOGIES A. Contaminated soil and water  Medical Parasitology: concerned primarily with the parasite that  lack of sanitary toilets and use of night soil affects humans and their medical significance, as well as their  Soil: Ascaris lumbricoides, Trichuris trichiura, Hookworm, importance in human communities. Strongyloides stercoralis  Tropical Medicine: branch of medicine, which deals with tropical  Water: Amoeba, Flagellates, Blood flukes diseases and other special medical problems of tropical regions. B. Food containing immature infective stage of parasite  Tropical disease: an illness which is indigenous to or endemic in  consumption of undercooked or raw freshwater fish, crab, tropical area but may also occur in sporadic or epidemic portions in snail, beef and pork areas that are not tropical. C. Arthropods, blood sucking insects and other wild or  Parasite: lives on or in the host usually on a larger organism which domesticated animals provides physical protection and nourishment.  Mosquitoes (Filaria and Malaria)  Host: harbours parasite and gives nourishment.  Triatoma bugs (Trypanosoma cruzi)  Sandflies (Leishmania) HOST-PARASITE RELATIONSHIP  Cats, dogs and house rats  Symbiosis: living together of unlike organisms, protection or other D. Another Person advantages to one or both partners.  Beddings and clothing  Mutualism: relationship is beneficial to both organisms.  Immediate environment he has contaminated  Commensalism: parasite derives benefit without reciprocating and E. One’s self without injury to the host or both.  Autoinfection: self is the source of infection  Parasitism: relationship where one organism, the parasite, lives in or  Enterobius vermicularis, Hymenolepis nana, and on another, depending on the latter for its survival and usually at the Strongyloides stercoralis expense of the host. TYPES OF VECTORS PARASITES ACCORDING TO THE MODE OF LIVING  Vector: responsible for transmitting the parasite from one host to  Ectoparasites: living outside the body of the host. EEF OA O SEZ another.  Endoparasites: living inside the body of the host. Types of Vectors:  Facultative parasites: able to live outside or inside the host and lead a. Biological vector: the parasite is seen inside the body of this both to a free and parasitic existence. organism and the parasite needs this organism for its development.  Obligate parasite: completely dependent to the host for its existence  Ex: mosquitoes, tsetse flies throughout its life. b. Mechanical vector: responsible only for transporting the parasite, the  Accidental/Incidental parasite: establishes itself in the host in which parasite is only seen on the surface of this organism and there will be it does not ordinarily live. no development on the parasite.  Occasional/Periodic: seeks its host intermittently to obtain  Ex: cockroaches, house flies nourishment.  Saprophytes: live in organic substances in state of decomposition. MODES OF TRANSMISSION  Erratic: those that live in an organ different from the one it usually  Soil transmitted parasitize.  Arthropod/ Vector transmitted  Zoonotic: animal parasites, non-human parasites that may cause  Food-borne human infections.  Water-borne  Skin penetration PARASITES ACCORDING TO THE DURATION OF PARASITISM  Congenital transmission  Temporary parasites: free living during part of existence, larval stage  Direct contact has a different host from its adult stage.  Permanent parasites: remain on the body of the host in all stages of PORTAL OF ENTRY its life cycle.  By mouth: most common area of invasion, entrance for intestinal protozoa PARASITES ACCORDING TO PATHOLOGIC LOCATIONS  Skin penetration  Spurious/Coprozoic parasite: passes digestive tract of humans  Intranasal: inhalation of eggs without infecting them  Transplacental infection  Coprophilic parasite: parasite multiply in fecal matter outside the  Transmammary human body  Sexual intercourse  Hematozoic parasite: lives inside the red blood cells  Cytozoic parasite: lives inside the cells or tissues PORTAL OF EXIT  Coelozoic parasite: lives in body cavities  Stool, Urine, Sputum, Blood, Tissue aspirates and biopsy, Orifice  Enterozoic parasite: lives in the intestine swab, Discharge TYPES OF HOST NOMENCLATURE  Definitive host: final host, harbours the adult and sexually mature  Classified according to the International Code of Zoological form Nomenclature  Intermediate host: harbours the larvae or asexual stage of the  Scientific name are Latinized parasite  Generic names consist of a single word written in initial capital letter,  Reservoir host: animal that harbours the same parasite of man the specific name always begins with a small letter.  Paratenic host: harbours a stage of the parasite where in no further  Names of genera and species are italicized or underlined when written. development in parasite takes place  Kingdom: Animalia TRANSCRIBED BY: RAINNE PARA311: CLINICAL PARASITOLOGY WEEK 2: INTRODUCTION TO PARASITOLOGY  Phylum: Nematoda FACTORS THAT DETERMINE THE INTENSITY OF PARASITIC INFECTION  Class: Secernentea  Topography of locality  Order: Ascaridida  Social condition  Family: Ascarididae  Age  Genus: Ascaris  Hygienic measure  Species: Ascaris lumbricoides  Sewage disposal  Water supply TYPES OF LIFE CYCLE  Simple or complicated TREATMENT  Most parasitic organisms attain sexual maturity at the definitive host  There are several options for treating parasitic infections. Many of  Larval stage of parasite may pass through different stages in an these drugs are toxic to the host and care should be exercised when intermediate host selecting the proper course of treatment.  As life cycle becomes complicated, the lesser chances are for the  antiparasitic medications individual parasite to survive.  change in diet  vitamin supplements LIFE STAGES OF A PARASITE  fluid replacement  Ova → Egg → Larva → Trophozoite → Cyst → Adult  blood transfusion  bed rest MODE OF REPRODUCTION  Deworming: use of anti-helminthic drugs in an individual or public Sexual health program.  Oviparous: “egg birth”, give birth to eggs that must develop before  Cure rate: usually expressed in percentage, number of hatching previously positive subjects found to be egg-negative in  Ovoviviparous: ones that produce eggs but retain them inside the examination of a stool or urine sample using a standard female body until hatching occurs, so that “live” offspring are born procedure at a set time after deworming  Larviparous/Viviparous: being born alive without eggs  Egg reduction rate: percentage fall in egg counts after Asexual deworming based on examination of a stool or urine  Binary fission: division in half sample using a standard procedure at a set time after  Parthenogenesis: unfertilized ovum develops directly into a new deworming individual, natural form of asexual reproduction in which growth and  Selective treatment: individual-level deworming with selection of development of embryos occur without fertilization by male sex cell treatment based on a diagnosis of an infection or based on presumptive grounds EPIDEMIOLOGIC MEASURES  Targeted treatment: group-level deworming where the risk group to  Epidemiology: science concern with the propagation of the disease, be treated (with or without prior diagnosis) may be defined by age, study of patterns, distribution and occurrence of disease gender or other social characteristics irrespective of infection status.  Incidence: number of new cases of infection appearing in a population  Universal treatment: population-level deworming in which the in a given period of time community is treated irrespective of age, gender, infection status or  Prevalence: usually expressed in percentage, number of individuals other social characteristics. in a population estimated to be infected with a particular parasite at a  Coverage: proportion of target population reached by an intervention. certain time  Drug resistance: genetically transmitted loss of susceptibility to a drug  Cumulative prevalence: percentage of individuals in the population in a worm population that was previously sensitive to the appropriate infected with at least one parasite therapeutic dose.  Intensity of infection: number of worm per infected person (worm  Efficacy: effect of a drug against an infective agent in deal burden) experimental conditions and isolated form of any context.  Direct: counting expelled worms during treatment  Effectiveness: measure of the effect of a drug against infective agent  Indirect: counting helminth egg excreted in feces, in a particular host, living in a particular environment with specific expressed in egg per gram ecological, immunological, and epidemiological determinants. DISTRIBUTION OF DISEASES PREVENTION AND CONTROL  Sporadic: appears only occasionally in one or at most a few members  Morbidity control: avoidance of illness caused by infections, may be of the community achieved by periodically deworming individuals or groups, known to be  Endemic: there is a steady moderate level of disease in human at risk of morbidity population  Information-education-communication (IEC): health education  Epidemic: there is a sudden outbreak or rise of incidence in human strategy that aims to encourage people to adapt and maintain healthy population life practices  Pandemic: when the disease have been disseminated in extensive  Environmental management: planning, organization, performance area of the world and monitoring of activities for the modification and/or manipulation of environmental factors or their interaction with human beings PATHOPHYSIOLOGY AND SYMPTHOMOLOGY OF PARASITIC INFECTIONS  preventing or minimizing vector and intermediate host  Traumatic or physical damage: when propagation parasites invade the skin and other tissues  reducing contact between humans and the infective agent causing destruction  Environmental sanitation: intervention to reduce environmental health risk  safe disposal and hygienic management of human and  Lytic necrosis: secretory and excretory animal excreta, refuse and waste water products elaborated by many parasites allow  control of vectors, intermediate host and reservoir of them to metabolize nutrients obtained from diseases the host and store these for energy  provision of safe drinking water and food safety production.  housing that is adequate in terms of location, quality of  Tissue reactions: cellular proliferation, white shelter and indoor living conditions, cell infiltration at the side of the parasite  facilities for personal and domestic hygiene  safe and healthy working conditions  Sanitation: provision to access to adequate facilities for safe disposal  Toxic allergic phenomena: when proteins or of human excreta, usually combined with access to safe drinking water other metabolites of the parasites are introduced into the body, there is sensation to ERADICATION AND ELIMINATION the foreign substance which may produce  Disease eradication: permanent reduction to zero of the worldwide hypersensitisation to anaphylactic shock. incidence of infection caused by a specific agent, as a result of  Deprivation of the host’s essential deliberate effort. Once this is achieved, continued measures are no nutrients and substances: the parasite longer needed. competes with its host for the available supply  Disease elimination: reduction to zero of the incidence of a specified of vitamin. disease in a defined geographical area as a result of deliberate effort. Continued intervention and surveillance are still required. TRANSCRIBED BY: RAINNE