Alejandro Marin Mendez is enthusiastic as he introduces himself to me and tells me about his work as a scientist.
Thinking he lives in Spain, he corrects me and explains he was born in Spain and currently lives in France. He mentions other places he’s lived as well as languages he’s learned. This is the life of a scientist, he happily notes.
We discuss Covid-19 restrictions and then go to the topic of Malaria.
He begins, I focus my research on the malaria parasite, which is called Plasmodium and it is unicellular.
There are 5 species of Plasmodium that affect humans: P. falciparum, P. vivax, P. malariae, P. ovale and P. knowlesi. It’s a vector-borne disease which means that it’s transmitted by mosquitoes (of the genus Anopheles).
According to the World Health Organization there are over 220 million cases of malaria infections reported in the world (mainly in the Southern hemisphere) and causes a 400,000 death toll per year, most of them being children under 5 years old infected with P. falciparum. Basically, it’s a massive health burden across the globe, especially affecting children in Sub-Saharan Africa.
The parasite needs to invade the RBC’s (red blood cells) as part of its life cycle. In the process of invading and egressing in and out of RBCs in a cycle that lasts between 24 and 72 hours, depending on the species, is when affected people develop all the symptoms (fever, anemia, headaches, muscular pain and in severe cases cerebral comma and death). Within the human body it mostly reproduces asexually, while later in the cycle it produces gametocytes that will commence sexual reproduction (2 cells give 1 cell) within the mosquito. I find that bit fascinating, that an unicellular organism has asexual and sexual reproduction across it’s life cycle!
My brain finds it hard to keep up….unicellular, P. falciparum, vector borne, RBC cycles…
I quick-note (aka doodle quickly) with stuff laying on my desk.
female Anopheles mosquito
An infected (and pregnant) Anopheles mosquito (vector) bites (sucks nutritious blood for maturation of its eggs) a human (host), injecting the malaria parasite (via its saliva glands) into the bloodstream (in the elongated form of a sporozoite).
The sporozoite (infective agent) enters the liver (hiding from the immune system) and multiplies (asexually) within liver cells (polyhedral hepatocytes). Liver cells eventually burst, sending what are now merozoites (who escape) out into the blood stream.
Did I get this right? Correct me if I didn’t.
Some merozoites (rounder form of the parasite) enter (bind to the surface) erythrocyte (aka, blood cell), where cycle continues in further complex stages: Ring stage, Trophozoite stage, Schizont stage (mature sporozoites)…while other merozoites develop into gametocytes.
Whew…there’s more but I’ll leave it for another day…
work in progress
Early in the zoom call, Alejandro referred to the parasite as a serial killer.
The last thing I ask: Do/does the parasite, in its various stages, communicate with each other? I paraphrase here ↓ (cuz I found it complicated).
He explains, the parasite is basically a single-celled organism. (This doesn’t answer my question.) He says, we can talk philosophically or perhaps spiritually, and perhaps we might consider it communicates. Perhaps. And then he goes into the molecular and hypotheses…
…serial killer…silently creeping…plasmodium falciparum…
mosquito goes dark. work in progress.
Muchas Gracias Alejandro. Me gustó hablar contigo!
Alejandro Marin Mendez is a scientist and an avid bicyclist. He’s combined the two things he loves into a Public Engagement initiative where he brings cutting edge science to Secondary Schools and the general public, around the world.
For more → scicling.org.
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