Review of Malaria, Environment, and

Agriculture Linkages

Financially supported by

http://www.ifpri.org/publication/malaria-and-agriculture

Health Background What is Malaria?

What role do mosquitos have?

Why does one place have malaria and not another? (Transmission)

Why are children more at risk than adults?

What can we do about malaria?

What is Malaria?“Malaria” is a parasite transmitted between humans by mosquito bites.

A malaria infection leads to:

Periods of Fever and periods of wellness (relapses)

Sweating, Chills, and Body-Aches

Headache, Nausea, and feeling hot

Fever of the Brain: Seizures and Death

Anemia or Jaundice

Infected person transmits parasite to mosquitos that bite them during the fever. (which then pass it to other humans).

4 Human Types of MalariaPlasmodium falciparum 90 % of human deaths

Deadly Brain Fever

Plasmodium vivax Less Deadly

Difficult to Treat

Fever every few months

Plasmodium ovale: Less Common

Less Deadly

Plasmodium malariae Less Common

Less Deadly

Other malaria types infect monkeys, antelope, birds, rodents, etc…

Malaria-Parasite Life-Cycle

Primary Health InterventionsBed-Nets: Insecticide Treated Nets (ITNs), and Long-Lasting Insecticide Nets (LLINs) to prevent mosquito bites and kill mosquitos

Indoor Residual Spraying (IRS) of Pesticides on the walls of homes to kill mosquitos

Drug-Treatments: Artemisinin Combination Therapies (ACTs) and Sulphadoxine-Pyrimethamine (SP) are two types of drugs commonly used to cure malaria infection

Environmental Management

“Environmental Management is where the environment is modified or manipulated to reduce malaria transmission by attacking local mosquitoes and requires an

understanding of the ecology of these species.”

WHO estimates 30 to 53 percent of the global malaria burden

(500,000 deaths) is attributable to modifiable environmental factors.

Examples of Environmental Management

Alternative Wet-Dry Irrigation

Clearing Canals of Vegetation

Sub-Surface Drainage of Wetlands

Leveling and Grading

Bacterial Larvicides

Larvivorous Fish - Other Predators

River modification to promote faster flows

Improved Livestock Housing

Adding Insect Screens to windows and doors.

Integrated Vector Management (IVM)

Evaluate the Efficacy of each

Intervention

Apply a full range of interventions

Implement Control Measures:

Bed-NetsDrug TreatmentIndoor Residual

SprayingEnvironmental Management

Measure the Impact on Mosquito

Populations and Human Infections

Test for Drug Resistance &

Pesticide Resistance

Identify Resistance Early ,

so it can be addressed.

Participatory Learning with the

Community: What is Working?

What is Not?

Change Strategies if You

Need to.

Test People for Malaria.

Measure the mosquito

population.

IVM is a way of managing

a malaria control program

Ross-MacDonald Model of Malaria Transmission

R0Basic transmission rate of the malaria parasite between humans and mosquitos

a number of bites of a human by a single mosquito per day (the “biting rate” of the local mosquitos)

b % of those bites that produce an infection in the human (how many mosquitos carry the infection)

c transmission efficiency from human to mosquito (how susceptible to infection is the human)

m number of mosquitoes per human host

Divided Byr how long the parasite is in the human’s blood-stream

(and transmitted to other mosquitos)

μ life-expectancy of mosquitoes (and how many people they can bite)

Intervention Effect on

R0

a2 b c m 1/r 1/μ

Biting Rate

% of mosquitos

infectedHuman

susceptibilityNumber of mosquitoes

duration of fever in humans

Mosquito Lifespan

Drug Treatment - - -

Indoor Residual

Spraying (IRS)- -

Bed-nets: ITNs and LLINs - -

Environmental Management - - -

How do Interventions reduce Malaria Transmission?

Conventional Interventions are Essential But Not Enough

It is not possible using the current set of interventions (Bed-Nets, Drugs, and Indoor Pesticide Spraying) to eliminate malaria from high transmission areas.

If R0 < 1 then transmission will tend towards zero over time and ultimately be interrupted. If R0 > 1 then malaria transmission will persist and spread among the population. (Ross 1911.)

Even scaling-up of current interventions to 100% coverage rates for sustained periods, transmission will still persist in Africa at levels of RC > 1.

Cotton, Malaria, & Pesticide Resistance

FAO in Sri Lanka: IPM + IVM = IPVM

Farmer Field Schools (FFS)

Agriculture-Health Linkages

http://www.bu.edu/bostonia/spring09/maize/

Uganda National Household Survey 2005/2006

7,426 households interviewed across the country

Rare combination of Questions - Agricultural Questions, Health Questions, and GPS coordinates

5,761 households reported agricultural production data (77%)

Crops Related to Malaria in UgandaCrops measure in comparison to Maize as baseline for crop-risk

Poor Households Middle Households*

Wealthy Households Effect:

Millet - Less Malaria than Maize

Beans - Less Malaria than Maize

Cassava - More Malaria than Maize

Ground-Nuts - More Malaria than Maize

Other Crops - Other Crops More Malaria than Maize

- Sweet Potato More Malaria than Maize

- Tree Crops More Malaria than Maize

* Middle-Wealth households did not have any crop-effects on malaria risk.

LivestockCattle Raising

associated with less malaria for adolescents (age 10 to 19), only in the poorest households

Cattle maybe diverting mosquitos away from humans who tend them - depending on anopheles species

Pig Raising associated with more malaria for adolescents

(age 10 to 19), only in the poorest households

Pigs maybe supporting mosquito populations for humans who tend them- depending on anopheles species.

Integrated Pest Management (IPM) Careful consideration of all available pest control techniques and

subsequent integration of appropriate measures

Discourage the development of pest populations and keep pesticides and other interventions to levels that are economically justified

Reduce or minimize risks to human health and the environment

Emphasizes the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms. *FAO

IPM Reduces input cost of PesticideReduces losses from PestsThereby Increases Profit per HectarePrevents / Reduces Pesticide-Resistance

History of Insecticide Resistance & Malaria

1960 & 1970: Insecticide Resistance EmergedTechnical and Financial obstacle to Malaria Control

Central American & India Cotton-growing Areas: Agricultural pesticide application led to resistance in mosquitoes.

WHO & FAO Response Guidance: Attempted to provide unified guidance Creation of IPM by FAO

1973 Banning DDT production in United StatesCosts grew significantly & effectively ended the Global Malaria Eradication Program

DDT use in small quantities for IRS Safe for humans but remains restricted by the WHO but politically sensitive

Anopheline insecticide resistant countries

Africa Asia / Europe Latin AmericaBenin Bangladesh BelizeBurkina Faso Burma Colombia Burundi Cambodia EcuadorCameroon China El SalvadorChad Greece Guatemala Côte d’Ivoire India HaitiEgypt Indonesia Mexico

Equatorial Guinea Iran Panama

Ethiopia Iraq Peru Gabon Laos VenezuelaGambia Malaysia Ghana Nepal Kenya Pakistan

Mali Papua New Guinea

Mozambique Sri Lanka

Nigeria Syria Rep. of Congo Thailand Senegal Turkey South Africa UAE Sudan Vietnam Tanzania Uganda Zambia Zimbabwe

Farmer Field Schools (FFS)Extension approach built upon principles of adult education to social learning

Experiential

Group-based

Participatory

Interactive

Group of farmers get together to study a particular topic.

Conservation / Organic Agriculture, Animal & Soil husbandry income Generating Activities such as handicrafts, etc.

Provides opportunities for ‘learning by doing’ Teaches basic agricultural and management skills for

farmers to become experts in their own farms.

A forum where farmers and trainers debate and share Debate observations and experiences Present new information from outside the community.

Integrated Pest-Vector Management (IPVM)

Program recently developed by FAO and UNEP

Engages communities through Farmer Field Schools in a rational decision making process to achieve the goals of IPM and IVM

FAO – UNEP Pilot program conducted in Sri Lanka from 2002 to 2006:

Sharp drop in insecticide use attributable to the training

Integration of fish (such as tilapia) into rice system to reduce pests and provide dietary protein

Community promotion of bed-nets within village

http://www.who.int/malaria/vector_control/ivm/gpirm/en/

154 Berg Agricultural HallBox: 2207DBrookings, SD 57007 Phone: 605.688.4792 Fax: 605.688.6733

To learn more about: Integrated Pest Management / Extension,

email Darrell Deneke Pesticides,

email Jim Wilson GIS Early Warning for West-Nile Virus / Malaria,

email Michael C. Wimberly

South Dakota State University Resources