Parasitology and HIV/AIDS Flashcards

Flashcards covering key concepts from a lecture on parasitology and HIV/AIDS, including parasite types, life cycles, diseases, treatments, and prevention, as well as key information about HIV/AIDS transmission, treatment, and prevention.

What is Medical Parasitology?

The study of parasites that cause human infections and the diseases they produce.

Name the two main divisions of Medical Parasitology.

Protozoology (study of protozoa) and Helminthology (study of helminths).

Define Symbiosis.

Living together of unlike organisms, potentially involving protection or advantages to one or both organisms.

Describe Commensalism.

A symbiotic relationship where one species benefits while the other is unaffected.

What is Mutualism?

A symbiotic relationship where both organisms mutually benefit.

Explain Parasitism.

A symbiotic relationship where one organism (the parasite) depends on another (the host) for survival, usually at the host's expense.

What is an Obligatory parasite?

A parasite that cannot survive outside of a host.

Define Facultative parasite.

A parasite capable of existing independently of a host.

What is an Endoparasite?

A parasite established inside a host.

What does 'infection' refer to in parasitology?

The presence of an endoparasite in a host.

Define Ectoparasite.

A parasite established on the exterior surface of a host.

What does 'infestation' refer to in parasitology?

The presence of an ectoparasite on a host.

Describe Permanent parasites.

Parasites that permanently live in or on the host.

What is an Accidental Parasite?

A parasite that infects an unusual host due to accident.

Define Aberrant parasite.

A parasite that infects a host where it cannot complete its normal development or life cycle.

What is a Definite host?

Also known as the final host; harbors the adult or sexual phase of the parasite.

Describe Intermediate host.

A host that harbors the asexual or larval phase of a parasite.

What is a Paratenic host?

A host in which the parasite does not develop further to later stages.

Define Reservoir host.

A host that harbors the parasite and serves as a source of infection for other susceptible hosts.

Describe Transport host.

A host responsible for transferring a parasite from one location to another.

What is an Accidental host?

A host other than the normal one that is harboring a parasite.

Define Carrier in parasitology.

A parasite-harboring host that does not exhibit clinical symptoms but can infect others.

What are the three components of a parasite's life cycle?

Mode of transmission, infective stage, and diagnostic stage.

Describe Direct life cycle.

A parasitic life cycle that requires only a single host to complete its development.

What is an Indirect life cycle?

A parasitic life cycle that requires two or more host species to complete its development.

List four sources of parasitic infection.

Contaminated soil, water, and food; vectors; animals; other persons.

Name three modes of parasitic transmission.

Oral transmission, skin transmission, and vector transmission.

Describe Direct transmission.

Person-to-person transmission of a parasite.

What is Vertical transmission?

Transmission of a parasite from mother to fetus or newborn.

Define Iatrogenic transmission.

Unintentional transmission of a parasite due to medical procedures.

List some routes of parasitic transmission.

Oral, sexually, accident in the lab, congenital, blood transfusion, open transplant, vector.

Name four major body areas affected by parasitic diseases.

Gastrointestinal (GI) and urogenital (UG) tracts, blood and tissue, liver/lung/major organs, miscellaneous locations (CSF, eye, skin, extremities).

Define Morbidity control.

Avoidance of illness caused by infections.

What is Environmental management?

The planning, organization, performance, and monitoring of activities for environmental modification.

Describe Environmental sanitation.

Intervention to reduce environmental health risks.

What does HIV stand for?

Human Immunodeficiency Virus.

What is the function of T-helper cell?

Normally the white cells fight off and kill any germs which enter our bodies.

What is the window period of HIV?

3 months

Describe Asymptomatic period of HIV.

No signs & symptoms; approx. 2-10 yrs

What does AIDS stand for?

Acquired Immune Deficiency Syndrome

What does ART stand for?

Anti-Retroviral Treatment; combination of several antiretroviral medicines used to slow the rate at which HIV makes copies of itself in the body.

How does ART work?

By reducing the viral load in the blood, ideally to undetectable levels, which prevents HIV from damaging the immune system, lowering the risk of opportunistic infections, reduces the likelihood transmitting HIV to others and improves overall health and life expectancy

Define U=U=ZERO.

Undetectable = Untransmittable = Zero risk of HIV transmission.

List some common side effects of ART.

Nausea, vomiting, diarrhea; fatigue, headache; insomnia

Describe long-term side effects of ART.

Metabolic changes (weight gain, insulin resistance), liver or kidney toxicity, bone density loss

What are the three modes of HIV transmission?

Unprotected penetrative sex, infected blood and blood products, mother to child transmission

Name the four body fluids implicated in HIV transmission.

Blood, semen/seminal fluid, vaginal fluid, breastmilk

What are the four principles of successful HIV transmission?

Exit, survive, sufficient, entry

List five ways to prevent HIV transmission.

Abstinence/delaying sexual debut, be mutually faithful, correct and consistent condom use/PrEP, do not use drugs/avoid alcohol, early detection and education

What is PrEP?

Pre-exposure prophylaxis; medicine to reduce chances of getting HIV from sex or injection of drugs.

Define PEP (Post-Exposure Prophylaxis).

An emergency HIV prevention treatment after potential exposure to reduce infection risk.

List two common symptoms of STIs.

Painful urination

Name one protozoal STI.

Trichomonas

List two skin parasites.

Pubic lice, scabies

What are protozoa?

A diverse group of unicellular eukaryotic organisms, mostly microscopic, belonging to the Kingdom Protista.

List four key characteristics of protozoa.

Unicellular protists, classified under Kingdom Protista, lack of cell wall, possess an outer membrane known as the periplast

Name the two regions of protozoan cytoplasm and their functions.

Ectoplasm (outer, clear, for shape and movement) and endoplasm (inner, granular, location of most organelles).

Name three locomotive structures of Protozoa.

Flagella, cilia, pseudopodia

What is the function of vacuole?

Involved in Digestion (food vacuoles), Osmoregulation (contractile vacuoles) and Storage of nutrients or waste

Describe Cyst Stage of Protozoa.

Dormant & Survival stage. The cyst is a resting form that allows the protozoan to survive harsh environmental conditions

Where can the cyst of protozoa be found?

Cysts are typically passed in the formed (solid) stool of infected individuals, as the environment in the large intestine favors cyst formation

Describe Trophozoite Stage of Protozoa.

Motile stage. This is the active, moving stage of the protozoan. Trophozoites move using structures like flagella, cilia, or pseudopodia.

Where can the trophozoite of protozoa be found?

In cases of diarrhea or dysentery, trophozoites are often passed in the watery stool, but they do not survive long outside the host because they are fragile and lack a protective wall.

What is Entamoeba histolytica?

A pathogenic protozoan that causes intestinal and extraintestinal amoebiasis, most notably amoebic dysentery.

What is the habitat of Entamoeba histolytica?

Resides primarily in the colon (large intestine), where it can remain non- pathogenic or invade intestinal mucosa.

How is Entamoeba histolytica transmitted?

Humans acquire infection by ingesting contaminated food or water containing viable cysts. Fecal-oral transmission is the primary route

What is the diagnostic hallmark Entamoeba histolytica

Ingested RBCs within the trophozoites seen in fresh stool or stained smears is pathognomonic of E. histolytica

Explain the pathogenesis of amoebiasis.

E. histolytica primarily invades the intestinal mucosa but can also spread to extraintestinal sites, especially the liver.

How Intestinal Amoebiasis occurs?

After ingestion of quadrinucleate cysts, excystation occurs in the small intestine, releasing trophozoites. These trophozoites migrate to the colon. effects on the colon is; Trophozoites lyse epithelial cells, invade the mucosa and submucosa and formation of flask-shaped ulcers is characteristic

How Hepatic Amoebiasis occurs?

When trophozoites penetrate the intestinal wall, they may enter the portal circulation and travel to the liver, causing amoebic liver abscesses. Liver Abscess Characteristics:

What are the treatments for Luminal Infection of Amoebiasis?

Paromomycin (aminoglycoside) and Diloxanide furoate (Furamide)

What are the treatments for Invasive Infection of Amoebiasis?

Metronidazole (Flagyl) then followed by a luminal agent to eliminate residual cysts

Distinguish Enthamoeba Coli's Cyst from E. hystolitica

E. coli cysts have 8 nuclei and irregular chromatoid bodies

Distinguish Enthamoeba Hartmanni from E. hystolitica

E. hartmanni is much smaller

Briefly describe Enthamoeba polecki

intestinal protozoan that primarily infects pigs and monkeys but can also be found in humans, especially in areas with close contact with animals. It is generally considered nonpathogenic

Briefly describe Endolimax nana.

nonpathogenic intestinal amoeba commonly found in the human colon. While it does not cause disease, its identification in stool samples is important for differentiating from pathogenic amoebas and for indicating fecal oral contamination.

Briefly describe Iodamoeba bütschlii

nonpathogenic intestinal amoeba found in the large intestine of humans and other primates.Although it does not cause disease, its detection is important as it indicates fecal contamination and poor sanitation.

Briefly describe Entamoeba gingivalis

protozoan parasite commonly found in the oral cavity, particularly in the gingival crevices and dental plaque of individuals with poor oral hygiene or periodontal disease. It is generally considered nonpathogenic

Briefly Describe Naegleria fowleri and what it causes?

Causes Primary Amoebic Meningoencephalitis (PAM), a rapidly fatal brain infection characterized by destruction of brain tissue.

What is the treatment for Negleria Fowleri?

Amphotericin B, often combined with Rifampin or Miconazole.

Describe Acanthamoeba species and what diseases they cause.

Causes Granulomatous Amebic Encephalitis (GAE): A chronic, often fatal brain infection and Acanthamoeba Keratitis: A serious eye infection that can cause severe pain and potentially lead to vision loss.

What are the treatments for Acanthamoeba.

GAE: Sulfamethazine and Keratitis: Itraconazole, Ketoconazole, Miconazole, Propamidine Isethionate and Rifampin