week 2

Question 1

environmental factors that affect malaria epidemiology

Answer 1

temp, season, dams, migration, deforestation, urbanization

Question 2

how does urbanization affect malaria

Answer 2

creates breeding sites
increases entomological inoculation rate
vectkrs become more tolerant of xenobiotics

Question 3

advantages of IVM

Answer 3

improves efficacy, cost effective, sustainable, preserve efficacy of existing tools, reduce evolution of IR

Question 4

limits of IVM

Answer 4

cost, technical capacities, human resources, political will

Question 5

what methods of control can be used in cities

Answer 5

LSM (few fixed and findable): habitat modification of manipulation, biological control (predatory larvivorous fish), larviciding
house improvements

Question 6

limits of LSM as a control

Answer 6

short residual effect, needs repeating often. toxicity for non-target species, labour and financial constraints

Question 7

what are the impacts of infection on a mosquito

Answer 7

DAMAGE- to tissues, midgut, increased susceptibility to other infections
DEPLETION- lower concs of aa in haemolymp, midguts use more glucose
BEHAVIOUR- decreases apyrase(enzyme catalyses hydrolysis of atp) activity, more time feeding
SURVIVAL (filariasis infection) FECUNDITY (malaria)

Question 8

what is involved in the insect innate immune response

Answer 8

1. physiochemical barrier- cuticle and peritrophic matrix
2. cellular defense- hemocytes (would healing, phagocytosis, encapsulation)
3. Humoral response- antomicrobial peptides, melanin

Question 9

what insecticide products contain and active ingredient as well as pyrethroid, and can be used on nets

Answer 9

chlorfenapyr

pyriproxyfen

Question 10

main mosquito resistance mechanisms

Answer 10

behavioural avoidance
cuticular resistance
target site mutates
metabolic resistancce

Question 11

main kdr mutations in the sodium channel

Answer 11

L1014F L1014S

Question 12

how do OPs and carbamates work

Answer 12

phosphorylate or carabamate active site serine of AchE

Question 13

IR operational resistance definition

Answer 13

the selection of a heritable characteristic in an insect population that results in the repeated failure of an insecticide product to provide the intended level of control when used as recommended

Question 14

loss of susceptibility/ developing resistance definition

Answer 14

the development of an ability to tolerate doses that would prove lethal to a majority of individuals in a normal population of the same species

Question 15

issues with current insecticides

Answer 15

only 4 used in irs, with two modes of action , therefore resistance increasing
only pyrethrpids used on nets- resistance seen

Question 16

with IR increasing what alternatives for vector control are there

Answer 16

1. spatial insecticides
2. attractive toxic sugar baits
3. microbial insecticides- bacillus used for control of aquatic insects like similum, aedes and culex

Question 17

what is temephos

Answer 17

OP larvicide to treat water infected with mosqs midges black fly larvaee

Question 18

major resistance development factors

Answer 18

application freq
popn isolation
rate of reproduction
persistence of effect
dosage

Question 19

define cross resistance

Answer 19

the mechanisms expressed may resist more than one insecticide

Question 20

define multiple resistance

Answer 20

an insect expresses more than one resistance mechanism

Question 21

what are the different ways to manage resistance in IRS

Answer 21

1. single formulation containing 2+ insecticides
2. fine-scale mosaic- application of diff MoA insecticides against the same popn eg. using 2 diff moa insecticides in diff dwellings in same village. mosqs likely to come into contact with a second insecticide if they survive exposure to first, reducing selection pressure for both insecticides
3. rotate insectidies with diff MoA over time

Question 22

monitoring of vector susceptibility objectives

Answer 22

1. baseline data collection at start of a programme in order to inform planning and insecticide choice
2. monitor susceptibility over time and compare with baseline
3. detection of resistance so management can be introduced

Question 23

what is LC50

Answer 23

conc of compound required to kill 50% popn

Question 24

what is resistance ratio

Answer 24

LC50 resistant popn / LC50 susceptible popn

Question 25

describe the steps taken in a resistance monitoring programme

Answer 25

1. field collection of bloodfed adults/larvae
2. species identification
3. rear to F1 generation and/or larvae to adults
4. WHO/CDC susceptibility testes
5. kdr RT-PCR or sporozoite rate (gives idea of impact of resistance on epidemiology)

Question 26

how to manage IR

Answer 26

1. reserve class of insecticide for vector control and exclude from agri and household use
2. ensure insecticide is applied properly and at the correct dose
3. use dose that kills heterozygote partially resistant vectors
4. mix compounds with diff MoA
5. rotations or mosaics of insecticides

Question 27

define urbanization

Answer 27

increased movement and settlement of population from rural to urban settings

Question 28

why might people move from rural to urban settings?

Answer 28

better jobs, education, health care, absence of electricity and water supply, drought, terrorism conflict, armed gangs

Question 29

what is unplanned urbanization?

Answer 29

to develop an area without planning infrastructure which is unhygienic and unhealthy for the settlement. can lead to over crowding, slums and development of activities favouring vector breeding sites

Question 30

what are the drivers of infectious disease outbreaks in cities?

Answer 30

1. unplanned urbanization- creates suitable habitats for vectors and rats
2. poor housing- local transmission
3. travel- dissemination of diseases
4. overcrowding slums- transmission, bad hygiene practices

Question 31

LF was traditionally a rural disease but now urban, why?

Answer 31

Unplanned urbanization- lack of sanitation - Culex vector lives in polluted water and latrines

Question 32

what endogenous factors of the mosquito affect malaria epidemiology

Answer 32

density
longevity
species
feeding preference
vectorial competency
vectorial capacity
immunity

Question 33

what endogenous factors of plasmodium affect malaria epidemiology

Answer 33

density
stage of development
compatibility
virulence

Question 34

what endogenous factors of man affect malaria epidemiology

Answer 34

age
immunity
genetic
sex

Question 35

what exogenous (environmental) factors affect malaria epidemiology?

Answer 35

temperature
season
dams
migration
deforestation
migration

Question 36

advantages of IVM

Answer 36

improves efficacy, cost effectiveness, sustainability, preserve efficacy of existing tools, reduce evolution of IRS

Question 37

limits of ivm

Answer 37

cost, technical capacities

Question 38

name two common kdr mutations

Answer 38

L1014F L1014S

Question 39

how do you manage IR in the field

Answer 39

monitor resistance in field popn
determine the extent of resistance
adjust insecticide used

Question 40

what mechanisms of resistance are seen in insects

Answer 40

metabolic
target site
reduced penetration
behavioural

Question 41

alternative methods for killing adult mosqs?

Answer 41

house improvements-eave tubes, insecticide treated material
insecticide treated clothing
lethal host-mimicking traps (animals treated with insecticide)
toxic sugar baits
LSM

Question 42

what different vector sampling methods are there

Answer 42

HLC
Net traps
CDC light traps
barrier screens#
electrocuting traps
immature traps

Question 43

when choosing a sampling method what should you consider

Answer 43

prevalence vector
vector behaviour- how will it interact with the trap?
biting rate
changes over time
every sampling method has some bias