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Questions and Answers
What is the initial form of the E protein prior to fusion?
What is the initial form of the E protein prior to fusion?
What triggers the conformational change necessary for the fusion process?
What triggers the conformational change necessary for the fusion process?
During the post-fusion state, how does the E protein change?
During the post-fusion state, how does the E protein change?
Where is the fusion peptide located in the E protein?
Where is the fusion peptide located in the E protein?
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What is the final structure of the E protein after the fusion process is complete?
What is the final structure of the E protein after the fusion process is complete?
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What major event led Napoleon to sell the Louisiana Purchase?
What major event led Napoleon to sell the Louisiana Purchase?
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Who first demonstrated that the transmission of a parasite causing filariasis occurred through mosquitoes?
Who first demonstrated that the transmission of a parasite causing filariasis occurred through mosquitoes?
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What was the conclusion drawn by Walter Reed regarding yellow fever transmission?
What was the conclusion drawn by Walter Reed regarding yellow fever transmission?
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Which genus and species of mosquito is identified as the vector for flavivirus infection?
Which genus and species of mosquito is identified as the vector for flavivirus infection?
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What is a crucial factor that makes a pathogen eradicable?
What is a crucial factor that makes a pathogen eradicable?
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Which year did the US Army establish the Yellow Fever Commission?
Which year did the US Army establish the Yellow Fever Commission?
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What significant public health issue can increase the urgency to eradicate a disease?
What significant public health issue can increase the urgency to eradicate a disease?
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Which event marks the beginning of outbreaks along the Mississippi River?
Which event marks the beginning of outbreaks along the Mississippi River?
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What is the predominant secondary structure of the fusion protein in Class II dengue?
What is the predominant secondary structure of the fusion protein in Class II dengue?
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How does the genome organization of a + sense genome facilitate immediate translation?
How does the genome organization of a + sense genome facilitate immediate translation?
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What distinguishes the mature viral proteins from the initial polypeptide precursor?
What distinguishes the mature viral proteins from the initial polypeptide precursor?
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What is the role of stem-loops in the viral genome?
What is the role of stem-loops in the viral genome?
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In the post-fusion structure of Class II dengue, what is the key characteristic of the trimer?
In the post-fusion structure of Class II dengue, what is the key characteristic of the trimer?
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What issue arises from the positive sense genome during translation and replication?
What issue arises from the positive sense genome during translation and replication?
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How is the fusion peptide located in Class II dengue distinct from Class I?
How is the fusion peptide located in Class II dengue distinct from Class I?
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Which of the following describes the maturation process to the pre-fusion state in Class II dengue?
Which of the following describes the maturation process to the pre-fusion state in Class II dengue?
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Which of the following symptoms is associated with severe malaria caused by Plasmodium falciparum?
Which of the following symptoms is associated with severe malaria caused by Plasmodium falciparum?
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What are the regions most affected by malaria globally?
What are the regions most affected by malaria globally?
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Which statement about Charles Laveran is accurate?
Which statement about Charles Laveran is accurate?
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What is the role of apicoplasts in the life cycle of Plasmodium?
What is the role of apicoplasts in the life cycle of Plasmodium?
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Which organism is known to be the primary vector for malaria transmission?
Which organism is known to be the primary vector for malaria transmission?
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Which of the following Plasmodium species is associated with the least severe form of malaria?
Which of the following Plasmodium species is associated with the least severe form of malaria?
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What is a common consequence of chronic malaria infections in children?
What is a common consequence of chronic malaria infections in children?
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What defines the term 'Apicomplexans' in relation to Plasmodium?
What defines the term 'Apicomplexans' in relation to Plasmodium?
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What happens to gametocytes after being taken up by a mosquito during a blood meal?
What happens to gametocytes after being taken up by a mosquito during a blood meal?
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Which statement accurately defines the ookinete?
Which statement accurately defines the ookinete?
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What role does the oocyst play in the life cycle of the parasite within the mosquito?
What role does the oocyst play in the life cycle of the parasite within the mosquito?
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How long does oocyst maturation typically take?
How long does oocyst maturation typically take?
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What occurs after the formation of the ookinete in the midgut of the mosquito?
What occurs after the formation of the ookinete in the midgut of the mosquito?
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What do sporozoites do after exiting the oocyst?
What do sporozoites do after exiting the oocyst?
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Which of the following is NOT a characteristic of gametocytes?
Which of the following is NOT a characteristic of gametocytes?
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What is formed when a male gamete fertilizes a female gamete?
What is formed when a male gamete fertilizes a female gamete?
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Study Notes
Louisiana Purchase & Yellow Fever
- The Louisiana Purchase was sold by Napoleon in 1803 due to massive losses from the Haitian uprising.
- Mid-late 19th century saw outbreaks of yellow fever along the Mississippi River.
- The Spanish-American War in 1898 led to the establishment of the US Army Yellow Fever Commission in 1900.
- Patrick Mason in 1878 demonstrated that a parasite causing filariasis was transmitted by mosquitoes.
- Ivanowsky in 1892 found a smaller-than-bacteria agent that transmitted tobacco mosaic disease, later identified as a virus.
- Walter Reed in 1901 determined yellow fever was caused by an agent that could pass through filters and was found in the blood of infected individuals.
- Reed’s team self-inoculated with mosquitoes that had bitten infected people, demonstrating the transmission mechanism.
Flavivirus Vector
- The vector for Flavivirus infection is Aedes aegypti.
Pathogen Eradication Factors
- Limited host range is essential for eradication.
- A pathogen is easier to eradicate when it affects only humans or a specific defined vector.
- Effective transmission intervention mechanisms, such as vaccines, are crucial.
- Previous successful eradication efforts in smaller geographic areas are indicative of potential for widespread eradication.
- Significant public health burden, with high incidence rates and deaths, reinforces the necessity for eradication.
Dengue Virus Entry Mechanism
- Dengue virus enters cells through receptor-mediated endocytosis.
- The low pH within the endosome triggers fusion with the viral envelope.
- The E protein is responsible for fusion and undergoes a conformational change from a dimer to a trimer.
- The fusion peptide is located within the E protein and becomes exposed upon the trigger of low pH, causing fusion of the viral and endosomal membranes.
Dengue Virus Entry: Feature Table
Dengue Virus Genome
- Dengue virus has a positive-sense genome.
- The positive-sense genome allows for immediate translation into proteins without the need for transcription.
- The virus utilizes the host's machinery for translation.
Dengue Viral Proteins
- The viral genome has a cap but lacks a poly A tail.
- Instead of a poly A tail, the virus uses stem-loops of RNA to signal translation termination.
- The viral genome encodes one large polypeptide precursor containing multiple proteins.
- Viral and host proteases cleave the polyprotein precursor into mature proteins.
- The positive-sense genome poses a challenge due to the potential for translation interference with replication.
Plasmodium Life Cycle in Mosquitoes
- Gametocytes are produced in the human bloodstream and are taken up by the mosquito during a blood meal.
- The gametocytes develop into gametes within the mosquito due to the temperature difference.
- Merozoites are also taken up by the mosquito but do not survive in the midgut for long.
- The Ookinete is a diploid zygote formed by the fertilization of male and female gametes in the mosquito's midgut.
- It migrates through the midgut epithelium and forms an oocyst on the basal lamina.
- The Oocyst is a capsule-like structure covered in host proteins that protect it from the mosquito's immune system.
- Nuclear division within the oocyst produces sporozoites.
- Sporozoites exit the oocyst and travel through the hemolymph to the salivary glands.
Plasmodium Falciparum: Origin and Impact
- Plasmodium falciparum is believed to be a recent human pathogen, introduced between 10,000 and 50,000 years ago.
- Charles Laveran observed parasites within red blood cells of malaria patients in the late 19th century.
- Sir Ronald Ross demonstrated mosquitoes as vectors of malaria using birds.
- Malaria has significantly impacted wars, particularly in the case of US troops in WWII.
- Drug resistance has led to increasing cases of malaria.
- Sporadic imported cases occur in malaria-free countries.
Malaria: Distribution and Risk
- Malaria is prevalent in Sub-Saharan Africa, Southeast Asia, South Asia, and Central and South America.
- Children are at the highest risk for malaria.
Malaria: Clinical Symptoms
- Malaria causes a range of symptoms, including headache, fever, shivering, joint pain, vomiting, hemolytic anemia, jaundice, hemoglobinuria, retinal damage, and convulsions.
- Symptoms fluctuate and exhibit periodicity.
- A severe form of malaria can develop 6-14 days after infection with Plasmodium falciparum.
- Severe malaria is characterized by enlarged spleen and liver, severe headache, restricted blood flow to the brain, renal failure, seizures, opisthotonus, uncoordinated eye movements, and coma.
Apicomplexans
- Apicomplexans are obligate parasites belonging to a phylum of protists.
- They evolved from a free-living photosynthetic ancestor.
- Apicoplasts, derived from an endosymbiotic event, are organelles essential for fatty acid biosynthesis.
- Apicoplasts are non-photosynthetic but are believed to have originated from red algae.
Major Plasmodium Species
- Five major Plasmodium species are associated with human malaria:
- Plasmodium falciparum
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium malariae
- Plasmodium knowlesi
Plasmodium falciparum Origin
- Plasmodium falciparum is the most severe form of malaria.
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Description
Explore the intricate history behind the Louisiana Purchase and the impact of yellow fever in the United States. This quiz covers key events, figures, and scientific discoveries that shaped our understanding of yellow fever, including the notable work of Walter Reed and the role of mosquitoes in disease transmission.