Module 9d Mosquitoes Part 2

Question 1

Malaria

Answer 1

kills 1 million per year
vector: Anopheles sp.
parasites:
1. Plasmodium falciparum (50%)
2. Plasmodium vivas (43%)
3. Plasmodium malariae (7%)
4. Plasmodium ovale (

Question 2

malaria transmission cycle in mosquitoes

Answer 2

mosquito is definitive host (development occurs)

1. ingests parasite during blood meal
2. travels to gut then salivary glands
3. escapes through saliva at next blood meal

Question 3

malaria transmission cycle in humans

Answer 3

human in intermediate host

1. receives parasite from saliva of mosquito
2. travels to liver (may hibernate)
3. enters bloodstream and RBCs where it multiplies
4. bursts RBC to get back into bloodstream

Question 4

malaria disease information

Answer 4

• sudden periods of fever, chills, lethargy, and sweating (highly predictable)
• after rupture of RBCs, new plasmodium merozoites are released along with toxins, prompting chills/fever
• next episode occurs in 48 or 72 hours depending on species

Question 5

Plasmodium falciparum

Answer 5

causes the most severe form of malaria because:

• attacks young and old RBC
• toxins from dead RBC cause toxemia and anemia
• infected RBC stick to epithelium of capillaries which impedes blood flow

Question 6

Plasmodium vivax

Answer 6

invade only young RBC
on 48 hours cycle
less severe symptoms (death unlikely)
relapses possible (remain dormant for awhile)

Question 7

Plasmodium ovale

Answer 7

causes malaria similar to P. vivas with milder symptoms

Question 8

Plasmodium malariae

Answer 8

invades only old RBC
on 72 hour cycle
can stay dormant with no symptoms for up to 50 years

Question 9

malaria drugs

Answer 9

Primaquine (for P. vivax)
Mefloquine (taken monthly)
Chloroquine (taken weekly)

Question 10

subfamily Culicinae mosquito-borne viruses

Answer 10

1. Togaviridae virus family (Alphavirus)
   - causes Chikungunya, Equine Encephalitis
2. Flaviviridae virus family (Flavivirus)
   - causes yellow fever, dengue, west nile

Question 11

chikungunya

Answer 11

parasite: togaviridae
vector: Culicinae
emerging US disease
symptoms: fever, joint pain, rash
not fatal
no treatment

Question 12

yellow fever virus

Answer 12

parasite: flaviviridae
vector: Aedes aegypti (Culicinae)
primarily a zoonotic disease
hemorraghic disease: sudden high fever, headache, nausea, pain, jaundice, bleeding gums, black vomit
effective vaccine available

Question 13

dengue virus

Answer 13

primarily zoonotic

virus: flaviviridae - 4 serotypes (DEN-1, etc)
vectors: Aedes aegypti, Aedes albopictus (Culicinae)

Question 14

transmission cycle of dengue virus

Answer 14

1. mosquito ingests virus
2. travels from gut - salivary gland
3. reinfects thru saliva

Question 15

symptoms of dengue fever

Answer 15

“Breakbone Fever”: extreme pain, fever, headache, rash
severe in certain cases: dengue hemorrhagic fever and dengue shock syndrome
no vaccine/medication, can only treat symptoms
can be fatal

Question 16

west nile virus

Answer 16

primarily zoonotic in birds
vectors: Culex sp. (Culicinae)
also transmitted thru blood transfusions, organ transplants, lab exposure, or mother to baby
most people don't show symptoms
death unlikely

Question 17

prevention and control of mosquitoes

Answer 17

1. prevention of bite
2. keeping populations at acceptable densities
3. minimize contact
4. reduction of longevity of females

Question 18

personal protection

Answer 18

• chemical repellants (DEET)
• avoid outdoors, use window screens
• heat nets/protective clothing
• bed nets with insecticides

Question 19

biological control

Answer 19

use of predators, parasites, or pathogens

predators: Gambusia mosquito fish (feed on larva)
pathogen: Bacillus thuringiensis israelensis (Bti) (larvae die when they ingest toxin)

Question 20

physical control

Answer 20

complete eradication of breeding sites by filling water sources

Question 21

chemical controls : larvicide

Answer 21

apply chemicals to water sources

• oils: kills by poisoning/suffocation
• insecticides: DDT or organophosphates
• insect growth regulators: interfere w/ development

Question 22

chemical controls : adulticide

Answer 22

apply to surfaces or air

• foggers drift chemicals thru areas
• DDT used on landing surfaces

Question 23

surveillance

Answer 23

core of all effective mosquitos control programs

know the diseases/mosquito species in your area