Question

Microbiology Tutorial: Introduction to Virology & Parasitology

Answer 1

Note: This is a reference for educational/studying purposes, not a question, please save all comments or questions for the end.

Answer 2

\({\bf{Viruses:}}\) an infectious particle or agent consisting of protein-coated DNA or RNA ;can only replicate within a host cell
- contains unique enzymatic activities not found w/in a host
- does not undergo metabolic activities
- does not contain organelles
- examples: the flu virus, measles, rubella, ebola, internet trolls, HIV, polio

\({\bf{Two~Main~Types:}}\)
- naked: contains nucleocapsid (nucleic acid + protein capsid)
- enveloped: contains nucleocapsid + lipid envelope
- naked viruses are more resistant to drying out/detergents/other harsh enviornmental conditions, but more susceptible to antibodies; enveloped viruses must have the envelope to replicate, requires moisture, are more likely to cause immunopathogenesis

\({\bf{Important~Discoveries:}}\)
- Adolf Mayer: first to transfer virus, used tobacco leaves to transfer tobacco mosaic virus
- Walter Reid: isolated yellow fever, the first isolated human virus
- chamberland filter: allows viruses to pass through but not bacteria, useful for determining whether an infection is caused by bacteria or viruses

\({\bf{Steps~of~Viral~Infection:}}\)
1. attachment and insertion into the host cell, occurs about once in every 1,000/10,000 the virus and the host make contact
2. synthesis of viral DNA/RNA
3. synthesis of viral proteins
4. assembly of virus (starting w/ capsid) and release; naked viruses are released by lytic cycle, enveloped viruses are released through budding of the membrane

Answer 3

\({\bf{HIV:}}\)
- widespread panic during the 1980's
- SIVs (ex: SIVcpz): (simmian immunodeficiency viruses) occur naturally in African primates
- main HIV strain is HIV-1 which came from chimpanzees
- spread to humans via zoonosis
- kind of getting into conspiracy territory here but there are some who believe it may have been spread through the oral polio vaccine/infected bushmeat

Answer 4

\({\bf{Parasites:}}\) infectious organisms (usu. single cell) that are generally considered living, ex. protozoa, helminths, cause 20% of infectious disease
- life cycles: asexual reproduction only, cyst formation, or a combination of asexual and sexual reproduction cycles

\({\bf{Brain~Infections:}}\) Naeglaeria fowleri and Acanthaemoba, inhabit water and infect through nose/eyes, cause meningoencephalitis
- meninges: infection of the membranes in the brain/spinal chord
- encephalitis: infection of the brain

\({\bf{Hemoflagellates:}}\) infect the blood/tissues, typically live in tropical regions and use insects as vector, have life cycles with distinct morphological stages
- T. brucei: causes African sleeping sickness through tsetse flies, damages spleen, lymph notes, and brain
- T. cruzi: causes Chagas disease

\({\bf{Apicomplexan:}}\)
- lack locomotor organelles
- sporozoans
- alternate between sex/asexual reproductive cycles
- transmit through arthropods, food, water
- ex. Plasmodium, Toxoplasma, Cryptosporidium

\({\bf{Malarial~Parasite~Life~Cycle:}}\)
1. asexual phse in human host:
- female mosquito transmits sporozite into host, generates merozoites through schizogony
- merozoites enter red blood cells, turn to trophozoites, and replicate, releasing merozoites
- merozoites become gametes
2. sexual phase in human host
- mosquito intakes infected red blood cells
- fertilization of gametes, formation of sporozoites
- sporozoites enter salivary glands in the mosquito which allow it to infect human host

Answer 5

\({\bf{Cestode:}}\)
- flatworms w/ thin bodies and a scolex which grips the intestinal tracts
- has proglottids which absorb food and release eggs
- two most common are T. saginata (beef tapeworm) and T. solium (pork tapeworm)

\({\bf{H. sapiens~juvenilus:}}\)
- transmitted through intercourse
- incubation period of 9 months
- simian form with abnormally large head to body ratio
- infection time is at least 18 years
- expensive to treat, can cost $250,00+ to treat until it leaves host

\({\bf{Common Vectors:}}\) arthropods, mosquitos, fleas, lice, flies, arachnids (ex. ticks)

Answer 6

This is the end of my tutorial; I hope you found it helpful. If you have any ∗relevant∗ comments or questions I will attempt to address them to the best of my ability.

Thank you for reading!