Vector Borne Disease

Question 1

What are vectors (in terms of disease)?

Answer 1

Anything that carries a pathogen from host to host

Question 2

What phylum of organisms make up a large proportion of vectors?

Answer 2

Arthropods

Question 3

What spreads malaria and how?

Answer 3

Pregnant female mosquitos
She bites a host for blood (blood provides nutrients to her babies) while she has contaminated salivary glands carrying the malaria parasite. She uses salvia to prevent the blood from clotting

Question 4

Malaria has R0 value can range from <1 to over 1000, how it can it be so high

Answer 4

Transmission in regions with high proportions of mosquitos is super high due to frequent contact with mosquitos and recovery rate is super low as resistance takes years to develop, allowing for the presence of malaria
Thus since beta is frequency-dependent here → R0=Beta/Gamma
With high beta and low gamma, you get high R0

Question 5

Malaria life cycle

Answer 5

1. Malaria parasite inside the saliva of a mosquito
2. Gets injected into the bloodstream of human where it goes to liver cells
3. Divides and amplify in liver cells –> schizonts
4. Schizonts move into blood and eat blood cells –> causes anemia
5. Blood cells can burst & release more parasites

Question 6

True or false: Sickle cells are resistant to malaria

Answer 6

True

Question 7

Which is the most serious malaria parasite

Answer 7

Plasmodium falciparum

Question 8

What kind of mosquitos spread malaria

Answer 8

-Anopheles
-Pregnant females

Question 9

Which mosquito is in anthropophilic (attracted to humans)

Answer 9

Anopholes gambiae

Question 10

Which mosquito lives well in urban environments

Answer 10

Anopheles stephensi

Question 11

What organelles are used to be photosynthetic

Answer 11

Apicocomplexan/apicoplast

Question 12

True or false: Malaria is like red algae

Answer 12

True

Question 13

How do you estimate R0 for vector-borne pathogens?

Answer 13

You multiply the R0 of both pathways together to get the total R0.
eg.) R0(human to mosquito) * R0 (mosquito to human) = R0total

Question 14

What is one of the best human mosquito vectors? Why is it that?

Answer 14

Aedes aegypti, it is all over the world as it is an aggressive invasive species in urban areas that specialize on human hosts

Question 15

What is vector competence?

Answer 15

Susceptibility of a vector to a given pathogen (Ch)

Question 16

What is vectorial capacity?

Answer 16

The expected number of infective mosquito bites that would eventually arise from all the mosquitos that would bite a single fully infectious person on a single day

Question 17

What is the main vector that causes yellow fever and dengue?

Answer 17

Aedes aegypti

Question 18

It is not as bad to get dengue once and recover, but it is not great to get it a second time… why?

Answer 18

Antibody dependent enhancement
-there are 4 types of different dengue

Question 19

True or false ticks are parasites

Answer 19

True

Question 20

What are hard bodied ticks called

Answer 20

Ixodidae

Question 21

What are soft bodied ticks called

Answer 21

Argasidae

Question 22

Ticks are vectors to what kind of disease

Answer 22

1. Crimean Congo Hemorrhagic Fever
2. Rickettsia
3. Lyme Disease

Question 23

What are Wilbachia symbionts

Answer 23

-Can change gametes in host to favor transmission
-Protect insects from viruses
-could help stop virus transmission through vectors

Question 24

What is an important member of the Rickettsiales group?

Answer 24

Mitochondria
-came from Rickettsia bacteria

Question 25

What makes it less worrying for disease transmission through ticks

Answer 25

Ticks only contact one host in their lifetime

Question 26

What is one exception that could make disease transmission through ticks a problem?

Answer 26

Vertical transmission -ticks live long and can transmit to multiple hosts

Question 27

What kind of tick spreads lyme disease

Answer 27

Ixodes scapularis -The deer tick

Question 28

True or false: Larvae of ticks that cause lyme disease are infected

Answer 28

False -Larvae are uninfected -No vertical transmission for lyme disease

Question 29

At what stage for ticks do they do the most transmission for lyme disease

Answer 29

Nymphs

Question 30

What are ticks preferred habitat

Answer 30

Wildland-urban interface -need nature

Question 31

For larval ticks they infect most species the same

Answer 31

False -Variation in infectiousness between species --> reservoir competence

Question 32

What is the dilution effect?

Answer 32

Pathogen gets diluted w/ less competent hosts

Question 33

What does it mean to clean ticks and what can do it

Answer 33

-Clean means to jill the tick -Lizards can do this, due to protein in the blood that kills the bacteria (Borrelia burgdorferi)

Question 34

Which stage of the tick would cleaning affect?

Answer 34

Nymph

Question 35

What is sleeping sickness caused by?

Answer 35

Trypanosomes carried by tsetse flies