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In the Amazon Rainforest, few animals are as dangerous to humans

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as mosquitoes that transmit malaria.

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In the Western Hemisphere, 90 percent of all malaria cases occur in the Amazon,

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but it’s not spread evenly across the tropical region.

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While malaria has decreased in the Brazilian Amazon,

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the disease has been steadily increasing in the Peruvian Amazon.

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In the past 5 years, Peru has had on average the second highest rate in the South American continent.

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Despite having interventions such as bed nets and indoor sprays,

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challenges still lie in identifying where to send resources before malaria outbreaks occur and spread quickly.

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Now scientists are attempting to tackle this challenge using NASA satellites.

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Our project in the Amazon is trying to understand the way malaria is transmitted in a tropical environment.

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We know that malaria risk is associated with certain environmental conditions

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that we can detect with satellites.

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To understand what environmental conditions to look for,

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it helps to know how malaria spreads in the Amazon.

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Malaria is caused by a parasite called Plasmodium

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and it’s transmitted to humans when mosquitoes carrying the parasite feed on your blood.

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There are roughly 40 species of malaria-transmitting mosquitoes worldwide,

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but in the Amazon the Anopheles darlingi species is most responsible for spreading malaria.

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The key to this study is predicting where the darlingi mosquito breeding sites are with NASA satellites.

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The project is using a model called the Land Data Assimilation System, or LDAS,

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and this gets input from NASA satellites that provide information on precipitation, temperature,

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and land cover. This informs scientists where mosquito breeding sites are likely to form.

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Mosquitoes need rainfall to form their breeding sites - puddles and ephemeral ponds.

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Rainfall also influences soil moisture. That will be important for vegetation.

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It will also change the humidity conditions near the surface where mosquitoes are breeding and living.

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Rainfall also eventually makes its way into the river

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and a lot of river discharge will mean that there’s lots of breeding sites along the banks for mosquitoes.

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There are strong patterns of malaria throughout the year, but these patterns aren’t consistent.

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As well as changes from season to season,

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global effects such as El Nino and climate change can disrupt where mosquitoes breed.

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Another factor that NASA satellites can detect is changes in land.

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The conversion of forest to non-forest is the most important change that we worry about for malaria control and the detection of hot spots.

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In Peru, land is cleared for activities such as agriculture, logging, and mining.

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And studies have found that cleared land in this region

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region increases the number of malaria-transmitting mosquitoes.

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Changes in the land doesn’t just influence where mosquitoes are,

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it also influences where humans are and this is a key component in this study.

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One thing that we’ve learnt in this project is just how important it is to consider human movement when thinking about malaria risk.

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People work on land that is used for agriculture, logging, and mining

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so that increases the amount of human traffic to that area.

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Where people meet malarial mosquitoes that’s where you get high risk of a transmission.

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Figuring out where people are getting infected forms the crux of predicting malaria.

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Peru currently measures how many malaria cases are being detected in health posts.

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But this isn’t always where true malaria outbreaks are occurring.

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People are not necessarily being diagnosed where they were infected with malaria.

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They could be getting infected where they are working, which could be 100 miles away.

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To incorporate this factor, the study is combining the LDAS data with models that

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give estimates about where people are traveling based on studies of seasonal employment.

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The study will predict where malaria outbreaks will occur 12 weeks ahead of time

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and help the country send resources to specific regions efficiently.

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While the project is focused on malaria,

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scientists say it can adapt to other diseases such as Zika and Leishmania.

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Precipitation and other environmental conditions are key factors in how diseases spread

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and with NASA satellites scientists are better understanding how

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diseases are interacting with a changing planet.

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