Dengue control

Monitoring and evaluation of programmes

Monitoring refers to a continuous tracking of a programme’s process or performance. The aim is to estimate the spread and burden of the disease over different periods of time. A sound and thorough monitoring and evaluation strategy allows decision makers to asses the effectiveness of various strategies on dengue transmission.

Methods of surveillance include:

1. Disease surveillance

Tracking the number of infected human cases.

Effective surveillance of dengue cases is essential:

  • To detect outbreaks in order to initiate timely and effective control measures;
  • Monitor the trends of incidence including temporal and geographic distribution of cases;
  • To monitor number of severe dengue cases and deaths;
  • To assess and confirm possibility of outbreaks based on serological evidence;
  • To monitor the impact of control interventions.

Epidemiological surveillance requires the report on the following indicators:

  • Suspected (clinical) cases of dengue and severe dengue;
  • Confirmed (laboratory-tested) cases of dengue and severe dengue;
  • Circulating serotypes (DEN-1,-2,-3 or -4);
  • Number of deaths from dengue or severe dengue;
  • Number of deaths among severe dengue cases, suspected or confirmed.

The effective prevention and control of epidemic dengue requires an active laboratory-based disease surveillance programme (using serological and virological diagnosis) that can provide early warning of impending epidemic transmission. However, for early detection of suspected cases, routine monitoring of fever cases in sentinel sites should be considered.

2. Vector surveillance

Tracking mosquito populations in areas of potential risk.

Surveillance on Ae. aegypti density is important in determining factors related to dengue transmission, in order to prioritize areas and seasons for vector control. Selection of appropriate surveillance strategies are based upon outcome/objective, also taking into consideration time, resources, and infestation levels.

Additionally, vector surveillance is required to sustain the control measures and detect any increase in vector density.

The most used indicators for vector surveillance are:

Larval surveys:

House index (HI): percentage of houses infested with larvae and/or pupae.

Container index (CI): percentage of water-holding containers infested with larvae or pupae.

Breteau index (BI): number of positive containers per 100 houses inspected.

Pupae surveys:

Pupa index (PI): number of pupae per 100 houses inspected.

Adult surveys:

Estimating adult population density using ovitraps, sticky traps, human landing collections or any similar traps.

Additional information is available on vector surveillance equipment in Dengue guidelines, Chapter 5.2.2.

3. Monitoring behavioural impact

Observing whether behaviours aimed to reduce dengue transmission are adopted and sustained by the community.

Communication for behaviour impact (COMBI) is a methodological process which blends strategically a variety of communication interventions intended to engage individuals and families in adopting healthy behaviours and maintaining those behaviours. COMBI uses a managerial view to plan social mobilization and communication for behavioural impact on public health.

COMBI aims for precise behavioural objectives and focuses on the implementation and maintenance of the behaviour through monitoring of communities. COMBI needs to be monitored by appropriate behavioural indicators apart from the above mentioned entomological indicators.