Malaria Surveillance

1. Vishnu M S Place photo here Malaria Surveillance “Baseball and malaria keep coming back - Gene Mauch.”

2. What is surveillance? Continuous scrutiny of the factors that determine the occurrence and distribution of disease and other conditions of ill-health Steps in surveillance:

3. Types of surveillance Depending on the method of data collection • Active surveillance – there is an active search for cases eg: house to house surveys. • Passive surveillance – data collection by public health agencies from the patients who come to them. eg: national notifiable disease surveillance system • Sentinel surveillance – can be active or passive.

4. Malaria surveillance National Malaria Control Programme(1953) National Malaria Eradication Programme(1958) According to the Modified plan of operation (1977), the endemic areas were divided into two. With API <2 With API >2 Surveillance is carried out in both areas.

5. Objectives: • Maintenance of an ongoing watch over the status of malaria in a group/community. • Detect changes in trends/distribution in malaria in order to initiate investigative/control measures. • It is a basis for measuring the effectiveness of anti malaria programme. • Ultimate objective - Prevention & control of malaria in the community

6. Two types of malaria surveillance • Active • Passive Aim of malaria surveillance: • Case detection – timely collection and examination of blood smears • Providing facilities for proper treatment

7. Surveillance inspector Surveillance worker Surveillance worker Surveillance worker 2000 houses 2000 houses 2000 houses 2000 houses Active Surveillance & Surveillance worker • The key player in active surveillance is the local surveillance worker or a MPW Surveillance worker

8. Rationale of fortnightly visits by surveillance worker • Technical justification for a fortnightly blood smear collection is based on transmission dynamics of malaria. • Incubation interval denotes the duration of the full cycle of malaria parasite. It is the sum of the time taken for the development of the parasite in the mosquito and that in the human being. • The incubation interval in case of P.vivax is approximately 22 days while for P.falciparum it is 35 days. • Thus, surveillance cycle of less than one incubation interval will catch most of the secondary cases before the commencement of next cycle.

9. Enquiry: WAS/IS there a fever case? Thick+Thin smear collection Presumptive Rx (Single dose of Chloroquin) Dispatch slides to unit lab Slide positive Returns to patient – A course of radical Rx Active Surveillance Surveillance worker/MPW : fortnightly visit to house YES House card entry

10. Local health agencies(PHC,Subcentres,Hospitals,Dispensaries,Physicians) Presumptive Rx Blood smears Slides collected by surveillance worker Radical Rx Positive Sent to unit lab Passive Surveillance Cases of fever which escape active surveillance are screened by passive surveillance Patients with fever or H/o recent fever

11. Parameters Of Malaria Surveillance • Annual Blood Examination Rate (ABER) • Annual Parasite Incidence (API) • Annual Falciparum Incidence (AFI) • Slide Positivity Rate (SPR) • Slide Falciparum Rate (SFR)

12. API and ABER • API = Confirmed cases during one year x 1000 Population under surveillance • Measure of malaria incidence in a community • Depends on ABER. • ABER = No. of blood smears examined in a year x100 Population covered under surveillance • Reflects the efficiency & adequacy of case detection mechanism. • A minimum ABER of 10% of the population/year was fixed under MPO.

13. 10th Five – Year Plan • ABER over 10% • API – 1.3 OR less • 25% reduction in morbidity & mortality due to malaria by 2007 & 50% by 2010