| These definitions and indices are important in epidemiological
surveillance and in planning the control strategy for malaria.
Endemic Malaria: Constant
incidence over a period of many successive years in an area.
Epidemic Malaria:
Periodic or occasional sharp increase of malaria in a given indigenous community.
Stable Malaria:
Amount of transmission is high without any marked fluctuation over years though seasonal
fluctuations occur.
Unstable Malaria:
Amount of transmission changes from year to year.
Vulnerability: Either
proximity to malarious areas or liability to frequent influx of infected people or
anophelines.
Receptivity:
Habitual presence of vector anophelines or existence of ecological factors.
Clinical Cure:
Relief of symptoms without complete elimination of parasites.
Radical Cure:
Elimination of parasites actually responsible for attack of malaria.
Recrudescence: Renewed
clinical activity seen during the first 8-10 weeks after primary attack (short term
relapse).
Recurrence: Renewed
clinical activity seen around 30th - 40th week following primary attack (long term
relapse)
Clinically Latent:
Symptom less phase between primary attack and relapse with splenomegaly, no parasite seen
in peripheral smear.
Insecticidal
Resistance: Development of resistance i.e. ability in strains of insects to tolerate
doses of toxicants which would prove lethal to the majority of the insect population of
the same species.
Epidemiological
Indices:
Annual Blood Examination
Rate (A.B.B.R.) = Smears examined in a year X 100 / Total population.
Annual Parasitic
Incidence (A.P.I.) = Total no. of positive slides for parasite in a year x 1000 /
Total population.
Annual Falciparum
Incidence = Total positive PF in a year x 1000 / Total population.
Slide Positivity Rate
(S.P.R.) = Total positive x 100 / Total slides examined.
Slide Falciparum Rate
(S.F.R.) = Total positive PF x 100 / Slides examined.
P. falciparum
Percentage (PF %) = Total positive for P. falciparum x 100 / Total positive
for MP
Entomological
parameters:
Adult vector density - Man
hour hand captures (per man hour density) = No. of mosquitoes collected/ No. of man hours
spent in search
Sporozoite Rate (%)
for each species = (No. of positive for sporozoites/ No. dissected) x 100
(I sincerely thank Dr.
P.P. Venugopalan, Former Medical Superintendent, Attavar Hospital and Professor
and Head of Community Medicine, Kasturba Medical College, Mangalore for his contribution)
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