• Crispin Chishimba

Mistakes can render a malaria combination control programme worthless




The use of long-lasting insecticide-treated nets (LLITNs), indoor residual spraying (IRS), fogging and larvicide applications are important interventions in the fight against malaria. However, these interventions can only be effective if they are implemented correctly. (And timely since they are time bound programmes)


Unfortunately, non-trained operators (unqualified programme officers) can make numerous mistakes when delivering these programmes, which can render them worthless and overly expensive to the organisations paying for them. (Employ qualified programme officers to run them)


The most common mistakes made by non-trained operators when delivering IRS, fogging and larvicide programmes include:


Not using the correct insecticide

This is the most critical mistake that can be made, as it renders the whole programme ineffective. Distinct species of mosquitoes have various levels of resistance to different insecticides. It is important to use an insecticide that is effective against the specific species of mosquito present in an area. The supplier, such as Regent Laboratories, can advise on the insecticides pertinent to the site's needs. (Establish the insecticide the local malaria vectors are susceptible to)


Applying the incorrect dosage

When using IRS, fogging and larvicide products, it is important to apply the correct dose to the highest efficacy rates, avoid higher than anticipated costs and cause potential safety concerns. (Programme officers and operators should be well trained in the correct interpretation of direction for use explained on labels attached to product containers)


Under dosing can lead to a shorter residual half-life and development of mosquito resistance due to exposure to sublethal doses. Consistency in the speed of application and the distance of the sprayer nozzle from the surface are critical factors to consider when applying insecticide to walls, ceilings, and other sprayable surfaces. The programme document will list the specific spray equipment and nozzles required.


Conversely, overdosing of IRS products can lead to higher than anticipated costs and potential safety concerns for those coming into close contact with the surfaces.


Applying Larvicide products without regard to the seasons

One of the most common mistakes is applying the larvicide too early or too late in the season. If it is applied too early (in larvicide), the insects may not have hatched and in the process the larvicide will lose its potency. They usually short residual effect. If it is applied too late, the insects may have already matured an adult mosquito and out of aquatic stage. The best time to apply the larvicide, is when the larvae are first hatching.


Larvicides need to be dispersed on to standing and stagnant water. (Do not apply larvicides to fast moving rivers and streams). Application of larviciding programmes to be timed for Dry and Winter periods only.


Failing to wear appropriate safety clothing (PPE)

It is so important for the operators to wear the correct safety clothing whilst conducting the various operations. Failure to do so can have serious health implications for the operators, especially with regards to their respiratory health. Training of how to use the safety equipment such as the respiratory masks, and how to wear the safety clothing is critical.


In the programme document, all the necessary equipment will be listed with the dates by which they must be procured in to meet the timetable which is determined by the seasons.


Conducting Surveys and follow-up monitoring

For an effective malaria control to work, an initial professional site survey is required. Surveys must be a site specific, and the subsequent vector programme designed using a combination programme of Nets, IRS, Fogging and applications of Larvicides


This should then be followed up by another survey to (evaluate the impact of the intervention, be it IRS, Use of nets or Larviciding). Re-visit elements of the programme for continuous improvement.