Lecture 20 - Insect & Disease Flashcards
Final Lecture date: 11/28/12
What are the two types of disease transmissions?
Mechanican transmission: spread by contact with host; pathogen contaminates external surface
Biological transmission: a vector plays a essential role in pathogen life cycle; it is also a host
What are the two types of biological transmission?
Horizontal transmission: pathogen/parasite moves from vector to host
Vertical transmission: pathogen/parasite moves from female vector to her eggs
What are the insect vectored pathogens?
- Protozoa: intercelluar parasites, extermely difficult to treat; no vaccines; chemotherapy highly toxic
- Viruses: intercellular parasites; vaccines generally work well
- Nematode worms: filariae treated with chemotherapy; adults removed surgically
- Bacteria: generally treatable with antibiotics; few vaccines
Protozoa (vectored pathogen)
intercellular parasites, extremely difficult to treat; no vaccines; chemotherapy highly toxic
Most difficult or impossible disease to treat
EX: malaria, leishmaniasis, chagas’ disease, african sleeping sickness
Viruses (vectored pathogen)
intercellular parasites; vaccines generally work well
Nematode worms (vectored pathogen)
filariae treated with chemotherapy; adults removed surgically (b/c the amount of dead debri can kill the patient)
Bacteria (vectored pathogen)
generally treatable with antibiotocs; few vaccines
Most difficult or impossible disease to treat?
a
Malaria - What are the 5 species of Plasmodium in humans?
falciparum (the worst, will simply kill you) knowlesi malariaw ovale vivax
DESCRIPTIONS!
Malaria Treatment and Prevention
bednets
chemical prophylaxis
Malaria Symptoms
Fever
Anemia (b/c killing red blood cells)
Liver & brain damage
Malaria Resistance
Sickle cell anemia
Thalassemia
Southeast Asian Ovalocytosis
Duffy Antigen Receptor
Thalassemia
form of anemia
high frequency in some Mediterranean populations
SE sian Ovalocytosis
red blood cells are oval-shaped
deformed rbc make parasitism difficult
usually rare, but in Southeast Asia in up to 15% of native people of Malaysia…DESCRIPTIONS!
Duffy antigen receptor
receptor for Plasmodium vivax
absence…DESCRIPTIONS!
Sickle Cell Anemia
occurs when the parasite enters a RBC
homozygous individuals rarely survive
Leishmaniasis
disease of animals.. that can infect humans!
Mediterranean,
South America: mucocutaneous
Middle East: “summer sore” in the military
Centeral East Africa mostly: visceral
Cutaneous Leishmaniasis
skin leisions, DESCRIPTIONS!
Mucocutaneous Leishmaniasis
occurs in south america
long history in humans
Visceral Leishmaniasis
causes a hugely enlarged spleen and organ failure
always deadly
Chagas Disease
vectors are Kissing Bugs
protozoans are transmitted via fecal pellets
Symptoms: sore at point of feeding by kissing bug on lip
acute myocarditis (hugely enlarged heart)
Transmission cycle.. DESCRIPTIONS!
African Sleeping Sickness
tsetse fly vector (closely related to house fly)
trypanosome in blood
Symptoms: bite lesion, then lethargy, then in coma and die
Viral Diseases
most vectored by mosquitos
West Nile Virus
Dengue Fever
Yellow Fever
West Nile Virus
humans are accidental hosts
primarily disease of birds, humans, and horses accidental hosts
(we can get it and it be gone in a few days, horses die)
Vertical and Horizontal transmission
