Malaria – PART 1
Protozoal disease, female anopheline
India is endemic for malaria, with unstable transmission rates
High transmission zone: > 1 / 1000, Low transmission zone: 0-1 / 1000
Most prevalent states: NE states, Chhattisgarh, Jharkhand, MP, Orissa
An. Culicifacies: rural, Peri-Urban
An. Stephensi: Urban
An. fluviatilis: hilly area, Forest
An. Minimus: foothills, NE states
An. Dirus: forest vector in NE
An. Epiroticus: Andeman and nicobar
All EXCEPT pl. OVALE is prevalent in India
Throughout world: vivax is widespread.
m/c in India is Pl. Falciparum
Life cycle
Asexual stage: man
1. Hepatic phase: sporozoites → hepatic schizonts → merozoites.
Remember : if hepatic forms persist: leads to relapse – seend in vivax and ovale
2. Erythrocytic stage: merozoites→ trophozoite → merozoite. This cycle goes on to invade RBCs.
Remember : duration of erythrocytic stage: vivax, ovale, Fp = 48 hrs, and P.malariae is 72 hrs
3. Gametogeny: after erythrocytis stage, some form gametocytes and infective to mosquito
Sexual stage: Mosquito
1. Sporogony: gametocyte is ingested by mosq. → exflaggelation in stomach. →ookinite → sporozoite
Mosquito features:
Anopheles: malaria
Clean water, no siphon, dawn dusk biting, exophillic, 1-2 kms flight, sophisticated mosquito
Aedes: dengue, Chikkungunya
Artificial water, siphon, day time, endophillic, 100-200 mts flight, fearless mosquito
Culex – filariasis, JE
Dirty water, siphon, midnight, exophillic, nusciance mosquito
Investigations:
Peripherl blood smear: Thick smear, thin smear.
Rapid kits: only in few areas, as approved by NVBDCP
Malarial indicators:
-API = (Confirmed cases during one year / Population under surveillance) x 1000
-API is a sophisticated measure of malaria incidence in a community. It is based on intensive active and passive surveillance, and cases are confirmed by blood examination.
- ABER = (Number of slides examined / Population) x 100. - AEBR is an index of operational efficiency. The annual parasite incidence (API) depends upon the annual blood collection and examination rates. A sufficient number of blood slides must be systematically obtained and examined for malaria parasite to work out accurately annual parasite incidence (API)
- SPR: slide positivity rate: percentage of slides positive for parasite, irrespective of species.
An. Stephensi: Urban
An. fluviatilis: hilly area, Forest
An. Minimus: foothills, NE states
An. Dirus: forest vector in NE
An. Epiroticus: Andeman and nicobar
All EXCEPT pl. OVALE is prevalent in India
Throughout world: vivax is widespread.
m/c in India is Pl. Falciparum
Life cycle
Asexual stage: man
1. Hepatic phase: sporozoites → hepatic schizonts → merozoites.
Remember : if hepatic forms persist: leads to relapse – seend in vivax and ovale
2. Erythrocytic stage: merozoites→ trophozoite → merozoite. This cycle goes on to invade RBCs.
Remember : duration of erythrocytic stage: vivax, ovale, Fp = 48 hrs, and P.malariae is 72 hrs
3. Gametogeny: after erythrocytis stage, some form gametocytes and infective to mosquito
Sexual stage: Mosquito
1. Sporogony: gametocyte is ingested by mosq. → exflaggelation in stomach. →ookinite → sporozoite
Mosquito features:
Anopheles: malaria
Clean water, no siphon, dawn dusk biting, exophillic, 1-2 kms flight, sophisticated mosquito
Aedes: dengue, Chikkungunya
Artificial water, siphon, day time, endophillic, 100-200 mts flight, fearless mosquito
Culex – filariasis, JE
Dirty water, siphon, midnight, exophillic, nusciance mosquito
Investigations:
Peripherl blood smear: Thick smear, thin smear.
Rapid kits: only in few areas, as approved by NVBDCP
Malarial indicators:
-API = (Confirmed cases during one year / Population under surveillance) x 1000
-API is a sophisticated measure of malaria incidence in a community. It is based on intensive active and passive surveillance, and cases are confirmed by blood examination.
- ABER = (Number of slides examined / Population) x 100. - AEBR is an index of operational efficiency. The annual parasite incidence (API) depends upon the annual blood collection and examination rates. A sufficient number of blood slides must be systematically obtained and examined for malaria parasite to work out accurately annual parasite incidence (API)
- SPR: slide positivity rate: percentage of slides positive for parasite, irrespective of species.
