Hello, we are back and live to talk about malaria once again!
This week, we will discuss how malaria can be transmitted from humans to animals and vice versa via the bite of a female Anopheles mosquito. This is referred to as zoonotic spillover. Generally, about 60-75% of human infectious illnesses come from pathogens that originally infected only non-human animal species. For a spillover event to occur, several factors facilitate the movement of pathogens. Both humans and animal species ought to be in close proximity to each other and activities such as poaching, and meat consumption of wild animals increase the risk of a spillover.
According to scientists, malaria parasites that infect humans today evolved from those that infected early apes. Additionally, one of the first parasites of malaria (Plasmodium reichenowi) to be discovered was in primates. This parasite was described to be morphologically similar to P. falciparum, suggesting a close relationship. However, subsequent studies disagreed on that stating that both parasites are host-specific, meaning that P. falciparum infected only humans while P. reichenowi infected chimpanzees. Interestingly, newer studies conducted in 2009 and 2010 debunked that old research as the new studies have shown that chimpanzees can now be infected with P. falciparum. In my opinion, this discovery provided evidence that either the parasites had evolved or the previous studies were somehow wrong. But, either way, this is a scary discovery. Considering the fact that humans are more often than not in close contact with chimpanzees, they (chimpanzees) will always be a reservoir for malaria parasites. This is proof that our best effort to eliminate malaria should not only be centered in human dwellings because as long as mosquitoes are able to transmit parasites between the two, residual malaria transmission will always persist unless both systems are dealt with. I hope we can do that, otherwise...
Let's discuss. What do you think is the role of host-parasite interaction in zoonotic spillovers, if at all there is any? Leave me a comment and I will get back to you as soon as possible. Bye for now!
Sources:
https://www.pbs.org/newshour/science/analysis-how-deforestation-helps-deadly-viruses-jump-from-animals-to-humans
Ellwanger, J.H. and Chies, J.A.B., 2021. Zoonotic spillover: Understanding basic aspects for better prevention. Genetics and Molecular Biology, 44.
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