Evolutionary Medicine Flashcards
Alexander Bivelich: Example of Coevolution
Alexander Bivelich exemplifies a victim of coevolution, showing how organisms adapt in response to one another, often creating an evolutionary arms race between host defenses and parasite offenses
Percentage of Parasitic Species
Approximately 40% of species are parasitic, illustrating how parasitism is a common survival strategy that drives complex evolutionary relationships
Behavioral Response of Chimpanzees to Intestinal Worms
Chimpanzees infected with intestinal worms eat rough leaves to help physically dislodge and expel the parasites, demonstrating a self-medicating behavior to reduce parasite load
Behavioral Response of Male Fruit Flies to Mite Infection
Male fruit flies infected by bloodsucking mites increase their mating frequency, potentially as a last-ditch effort to pass on genes before the infection impacts their survival
Alexander Fleming’s Contribution and Warning (1928)
In 1928, Fleming discovered penicillin, the first effective antibiotic, revolutionizing infection treatment. He cautioned doctors about the risk of resistance from overuse and misuse of antibiotics
Reasons Bacteria Coevolve Faster than Insects
Bacteria have an edge in coevolution due to: (1) rapid reproduction–short generation times lead to quick evolutionary changes, (2) high mutation rate–frequent mutations increase genetic diversity, (3) haploid nature–single gene copies mean mutations have immediate effects, and (4) gene transfer–bacteria can acquire beneficial genes from other bacteria through conjugation and transformation
Conditions in Russian Prisons Favoring Microbial Evolution
Russian prisons encourage microbial evolution due to: (1) overcrowding–close quarters increase disease transmission, (2) inadequate medical resources–limited treatment fosters resistance, and (3) high immunocompromised population–diseases easily spread and adapt
Remarkable London Enterococcus Strain
A strain of Enterococcus identified in London shows resistance to all standard antibiotics, highlighting the challenge posed by superbugs in modern medicine
Methods to Reduce Bacterial Resistance Selective Pressure
Strategies include: (1) antibiotic stewardship–restrict and carefully manage antibiotic use, (2) targeted therapy–use narrow-spectrum antibiotics when possible, (3) infection control–strict hygiene in healthcare settings, (4) alternative treatments–explore non-antibiotic therapies, and (5) enhanced hygiene–reduce infection spread to prevent overuse of antibiotics
Virus Characteristics and Living Status
Viruses are non-living particles that contain DNA or RNA within a protein shell. They cannot reproduce or carry out metabolic functions independently, requiring a host cell for survival and replication
Reasons HIV Evolves Easily in Hosts
HIV evolves rapidly within human hosts due to: (1) high replication rate–frequent reproduction generates numerous variants and (2) mutation frequency–reverse transcriptase introduces errors, adding diversity
Common HIV Infection Routes
HIV primarily spreads through: (1) blood transfusion or contact, (2) sexual contact, and (3) mother-to-child transmission during childbirth or breastfeeding
Origin Hypothesis of HIV-1
HIV-1 likely originated from cross-species transmission, particularly from Pan troglodytes (chimpanzees) to humans, through the consumption of bushmeat
Primary Strain Causing Global AIDS Epidemic
The global AIDS epidemic is largely caused by the HIV-1 strain, known for its high transmissibility and virulence
Significance of Protecting Pan t. troglodytes (Chimpanzees)
Conservation of Pan t. troglodytes is crucial to prevent further zoonotic diseases from transferring between species, especially strains that could affect human populations
CCR5 Receptor and Its Role in HIV
The CCR5 receptor is essential for HIV entry into T-cells. HIV binds to CD4 and CCR5 receptors on T-cells to infect them, leading to immune system weakening
Genotype and Phenotype of HIV-Resistant Individuals
Individuals homozygous for a CCR5 mutation (lacking CCR5 receptors) are resistant to HIV. This mutation prevents HIV from binding to and entering T-cells
1347 Selective Pressure Linked to HIV Resistance
The Black Death in 1347 may have selectively increased the frequency of CCR5 mutations in European populations, potentially conferring resistance to diseases like HIV
Potential Effects of a CCR5-Blocking Drug
Blocking CCR5 receptors with a drug could prevent HIV from entering cells, offering a therapeutic strategy but possibly affecting immune response regulation
Relationship Between Parasite Transmission Mode and Toxicity
Parasites relying on direct human contact for transmission are typically less toxic to keep hosts mobile. In contrast, vector-borne or waterborne parasites (e.g., malaria, cholera) can afford higher toxicity as host movement is not essential for spread
HIV Mechanisms Leading to AIDS
HIV targets helper T-cells, using reverse transcriptase to integrate its RNA into the host genome, where high replication and mutation rates undermine immune defenses, leading to AIDS
