Parasitology, 01 Intro.

Reservoir host (type of host)

Usually an arthropod or vertebrate other than the definitive host which harbors the parasite and is actively transmitted to the next host thus ensuring continuity of the parasites life cycle

Hyperendemic (2nd category of frequency and distro)

a disease with a high incidence constantly present in a given community

Endemic & Endemicity (1st category of frequency and distro)

a disease with a low incidence but is constantly present in a given community. Ex. Malaria is endemic in central Africa Endemicity is commonly associated with a certain degree of tolerance to the pathogen

Zooanthroponosis (5th type of Zoonosis)

a human disease which is transmitted to animals

Types of parasites according to habitat (3 types)

-Ectoparasite (lives outside of host, lice) -Endoparasite (lives inside host, amoeba) -Erratic Parasite (parasite not in usual habitat or organ)

Maturation and reproduction (3rd phase of parasitism)

Involves the parasite's use of the host's nutrients for growth, energy and multiplication

Medical Parasitology

Is concerned primarily with the animal parasites of man and their medical significance, as well as their importance in human communities.

Airborne (3rd portal of entry)

Airborne. Parasite inhaled to nose, to nasopharynx, to intestine. Ex. eggsof E. Vermicularis and A. lumbricoides

Spurious/coprozoic Parasite (relationship)

Are foreign species of parasite that has passed through the human body (GIT) without sign and symptoms of its presence

Amphizoic parasite (relationship)

Are free-living parasites that can colonize and invade the brain and other sites (skin, lungs, eye)

Parasitology

Area of biology concerned with the phenomena of dependence of one living organism on another

Reinfection

person is infected with a parasite then after months of cure, again gets reinfected with the same species of parasite

Carrier

person who harbors a particular pathogen without manifesting any signs and symptoms

Vectors

are animate or inanimate objects that carries the infective stage of the parasite

Mutualism (host-para relation)

association between two organisms living together where in both are benefited to the situation and can exist independently if separated

Endoparasite (habitat)

-Parasite that lives inside the body of the host -invade deep and internal organs of the body. Ex amoeba

Two factors playing a role in parasitic disease distribution (Geographical distribution of parasites)

1) Area endemicity (native) of the parasite 2) Condition allowing spread/distribution of parasite

Host

-are organisms where the parasite derive or depends their sustenance or nourishment -larger than a parasite

Parasitism (host-para relation)

-association between two organism where one is dependent upon another for existence -the host is injured through the activities of the parasite

Commensalism (host-para relation)

-association of two organisms that live together and one benefits from the relationship without benefiting the other -parasites derive benefit from the host

Symbiosis (host-para relation)

-close association between two organisms of different species (host and parasite) where either can not exist independently.

Types of parasites according to type of host (4 types classified based on their role in the life cycle of the parasite)

-definitive/final host (para reach sex mature & reproduce) -intermediate host (para larval, not sex mature) -reservoir host (host transmits para to another host) -paratenic host (host carries non-developed para)

Classical diagnosis of parasitic infection

-easy when patient lives in an endemic area and the MD is familiar with the manifestation of infection -problem if disease is uncommon in the community or with migrants in the community -investigate where patient came from

Dioecious Parasite (relationship)

-having male and female reproductive organs in different individuals or separate sexes. Ex. Ascaris

Types of parasites according to relationship (9 types)

-obligate (complete dependence or death) -facultative/opportunistic (can live on its own) -amphizoic (free-living but can invade & colonize brain, skin, lungs, eyes) -incidental/accidental (living in not its normal host) -permanent (entire or early life to maturity in host) -spurious/coprozoic (passed through GIT with no sign or symptoms) -hermatozoic (lives inside RBC, maalaria) -dioecious (separate male and female (like us)) -monoecious or hermaphroditic (one organism has both sexes, tapeworm)

Definitive/final host (type of host)

-one in which the parasite reaches sexual maturity (adult sexual stage) and undergoes reproduction to complete their life cycle -the definitive host is usually a vertebrae. Ex. Malarial parasite reach sexual maturity and undergo fertilization in the mosquito

Paratenic host (type of host)

-one in which there is no parasite development but can remain alive and is able to infect other susceptible host -one which carries the infective stage of parasite in an arrested state

Mechanical/Phoretic Vector

-one that only transmit a parasite without being a host -transmit parasite to host, parasite stay in the host but does not undergo development -not essential to the life cycle of the parasite Ex. mosquito, flies

Parasite

-organism that lives on or within the body of another organism from whose tissue it gets its nourishment for survival and to whom it does some damage -usually cannot exist as free-living -dependent on the host for existence

Ectoparasite (habitat)

-organism that lives outside the body of the host -produce pathology on the external surface of the body. Ex. Lice

Types of parasites according to pathogenicity (2 types)

-pathogenic (causes injury to host) -non-pathogenic (does not injure host)

Infestation

-presents of the parasite on the host -development and reproduction of the parasite on the surface of the body of the host

Biological Vector

-transmit the parasite only after the vector has completed its development within the host -serves both as a vector and a host for the development stage of the parasite Ex. anopheles mosquito (malaria)

Facultative/opportunistic parasite (relationship)

-when a parasite is capable of living even without a host -can exist in either a free-living state or may become parasitic when the need arises

Six types of Exposure and Infection

1) Autoinfection (re-exposure from within one's body) 2) Reinfection (reinfected after cured) 3) Superinfection/Hyperinfection (1 host, 2+ para) 4) Infection (entry/invasion in host) 5) Infestation (present/development on host) 6) Carrier (host carries para, no sign or symptom)

Two methods to diagnose parasitic infection

1) Classical diagnosis 2) Laboratory diagnosis

Five Categories of frequency and distribution of parasitic disease

1) Endemic (low incidence but constantly present) 2) Hyperendemic (high incidence always present) 3) Epidemic (sharp rise high morbidity) 4) Sporadic (appears occationaly) 5) Pandemic (extensive world wide)

Six types of Zoonosis (disease of animals transmittable to man)

1) Enzoonosis (common to man and reservoir host) 2) Parazoonosis (man is accidental host) 3) Anthropozoonosis (acquired from other vertebrates) 4) Amphixenosis (common to man and verterbrates) 5) Zoonanthroponosis (human to animal transmission) 6) Anthroponosis (human but evolved from other source)

Two types of Vectors

1) Mechanical/Phoretic (only transmits, not essential to life cycle ex mosquito & flies). 2) Biological (transmits after development)

Host-Parasite relationship (4 types)

1) Symbiosis (host & para rely each other) 2) Commensalism (para benefits from host) 3) Mutualism (host & para benefit but can live apart) 4) Parasitism (para hurts host)

Four Phases of Parasitism (for a parasite to establish itself in its host, it must undergo...)

1) contact and entry to the host 2) migration of the parasite in the host to its habitat 3) maturation and reproduction 4) exit and development outside of the host for dissemination/transmission/spread

Seven types of Contact and entry to the host (1st phase of parasitism)

1) contaminated water 2) contaminated soil 3) food with immature infective stage of the parasite 4) blood - sucking insects as vectors 5) domestic or wild animals harboring the parasite 6) One's self 7) another person, her clothing or bedding

Five Portals of Entry

1) mouth (most common) 2) skin 3) airborne 4) transplacental (mom to fetus) 5) sexual

Three components involved in the study of parasitology...

1) parasite 2) host 3) environment

Endemicity of parasite (1st Geographical distro)

1) presence & habits of a suitable host 2) easy escape of the parasite from the host 3) environmental conditions which enhances the survival of parasite outside the host

Six things to consider in treatment

1) severity of infection 2) duration of infection 3) intensity & probability of reinfection 4) efficacy (ability to produce desired result) of the treatment 5) availability of the drug 6) toxicity of the drug

Five Conditions that affect the spread/distribution of parasites (2nd Geographical distro)

1) through irrigation projects 2) inadequate individual and community sanitation 3) low standard of living 4) ignorance 5) migration of population impt. factor or wordwide spread of parasitic disease

Five types of Prevention & Control against parasitic infection

1) treat infection in order to reduce source of exposure 2) teach and train individual about personal hygiene 3) proper waste disposal 4) comprehensive control on vehicles of infection 5) complete destruction of vectors and control of reservoir hosts

Laboratory diagnosis of parasitic infection (purpose is to make specific diagnosis)

A) collect proper specimen like stool, urine, blood, sputum, aspirate from body orifices, tissue scrappings B) know how & when specimen is to be obtained C) precautionary measures for satisfactory specimen for exam 1) clean & sterile specimen bottle 2) E. histolytica specimen should be examined right away to see trophozoite stage of parasite 3) specimen should be examined by skilled lab personnel D) Other lab method used: stool exam, urinalysis, CBC, tissue scrapping, X-ray, serology, biopsy, animal pathogenicity test

Treatment Modalities (easy if you have accurate & specific lab diagnosis)

Chemotherapeutic agents, Surgical intervention

Environment

Habitat of the parasite where they live and get their nourishment

Monoecious or hermaphroditic Parasite (relationship)

Having male and female reproductive organs in the same individual. Ex. Tapeworms

Superinfection/Hyperinfection

Host is harboring more than one parasite at a time

Mouth (1st portal of entry)

Mouth is most common a) ingestion of infective stage (Ex. cyst/embryonated egg) b) intimate oral kissing (Ex. gingivalis/T. tenax)

Intermediate host (type of host)

One in which the parasite harbors the asexual or larval stage of development but does not reach sexual maturity (immature asexual larval stage)

Erratic parasite (habitat)

Parasite found in an organ not its usual habitat

Pathogenic Parasite (pathogenicity)

Parasite that causes injury to the host by its mechanical or toxic activitys

Non-pathogenic (pathogenicity)

Parasite that does not cause injury

Incidental/Accidental parasite (relationship)

Parasite that establishes itself in a host in which it does not ordinarily live

Hermatozoic Parasite (relationship)

Parasite that lives inside blood cells. Ex. Malaria

Permanent Parasite (relationship)

Parasite that remains on or in the body of the host from early life until maturity or for its entire life (ex. ascaris)

Exit and development outside of the host for dissemination/transmission/spread (4th phase of parasitism)

Portal of exit: 1) GIT via feces or vomitus 2) Kidney via urine 3) Circulation upon blood meal of arthropods or insects 4) Nasal cavity thru sneezing or coughing 5) Genitalia via sexual contact

Sexual (5th portal of entry)

Sexusl. Acquired through sexual contact. Ex. T. vaginalis

Skin (2nd portal of entry)

Skin penetration of infective stage larva to skin a) directly Ex. Cercaria of schistosoma Filariform larva of hookworm b) indirectly through insect vectors Ex. Infective stage larva of trypanosoma & leishmania

Pandemic (5th category of frequency and distro)

Spread of communicable disease that has been disseminated over extensive areas of the world

Transplacental (4th portal of entry)

Transplacental. parasite from mother, transmitted to the fetus in utero Ex. T. gondii

Migration of parasite from host to habitat (2nd phase of parasitism)

after it's entry, it is carried or actively migrates to a location where it matures and produce progeny (babies)

Infection

connotes the entry/invasion of the infective agent in the host

Anthroponosis (6th type of Zoonosis)

disease presently restricted to man but which evolved from other source

Amphixenosis (4th type of Zoonosis)

if disease is common to man and other vertebrates

Parazoonosis (2nd type of Zoonosis)

if man is an infrequent / accidental host

Autoinfection

infection acquired by an individual resulting from their own direct source of re-exposure

Anthropozoonosis (3rd type of Zoonosis)

infection acquired by man from other vertebrates Ex. T. canis / T. cati

Sporadic (4th category of frequency and distro)

parasitic disease that appears occasionally in one or some members of the community

Enzoonosis (1st type of Zoonosis)

parasitic infection common to man and reservoir host Ex. tapeworm

Epidemic (3rd category of frequency and distro)

sharp rise with high morbidity of the disease which is occasionally present in the community