Epidemiology triangle of Malaria

Case study No. 1

Agent: Plasmodium Falciparum Host: Humans and female Anopheles mosquitoes Environment: Watery breeding places What control and prevention measures could be adopted to break the epidemic/epidemiological triangle/cycle of the disease?

Answer: The epidemiological triangle/cycle for Malaria could me shown as:

Plasmodium

Humans & Female Anopheles mosquitoes (vectors)

Watery breeding placess

 Following control and prevention measures can be implemented at the various levels of

the chains of the epidemiological triangle/cycle. 1. Break the chain between host and environment To break the chain between host and environment for the transmission of malaria 

Clear swampy areas and bushes

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Ensure proper disposal of waste

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Drain water for irrigation around villages and houses (Drain wetlands)

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Reduce the ambient conditions so mosquito dies before transmitting the malaria parasite

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Avoid living in marshy areas

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Improve housing conditions to reduce contact with mosquitoes

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Cleaning of drainage canals

2. Break the chain between host and agent To break the chain between host and agent in the malaria disease 

One can take anti-malaria drugs (For uncomplicated malaria artemisinin-based combination therapies (ACTs), Severe malaria should be treated with injectable artesunate (intramuscular or intravenous) and followed by a complete course of an ACT as soon as the patient can take oral medicines.

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Vaccination (There is currently no commercially available malaria vaccine, despite many decades of intense research and development effort. The most advanced vaccine candidate against Plasmodium falciparum is RTS, S/AS01.

3. Break the chain between the environment and the agent To break the chain between the environment and the agent 

Spray the breeding sites for mosquitoes

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Indoor residual spraying (IRS). WHO Pesticide Evaluation Scheme (WHOPES) currently recommends 12 insecticides belonging to 4 chemical classes for IRS. Among these DDT (dichloro-diphenyl-trichloroethane) has a comparatively long residual efficacy, lasting more than 6 months, and continues to be a widely used insecticide for IRS.

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Outdoor spraying with DDT, Malathion or dieldrin.

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Larval source management. For example Larviciding is only recommended for areas where mosquito breeding sites are few, fixed, findable, and where the sites are easy to identify, map and treat. Larviciding could be done with DDT, oil or temephose or even by large scale distribution of larvivorous fish.

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Thermal fogging

4. Break the vector and host chain To break the vector and host chain

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One can sleep under mosquito net.

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Use of insecticides nets (ITNS)

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Long-lasting insecticidal net (LLINS)

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Intensive health promotion

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Global malaria eradication program (GMEP)

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Personal protection measures such as window screens, insecticide treated hammocks, repellents, and protective clothing.