Andrew Gregory, conservation biologist at University of North Texas.By Ignacio Palma
The arrival of mosquitoes with avian malaria, which since the 19th century has caused severe damage to the endemic avifauna of Hawaii, has scientists like Andrew Gregory on alert. He warns that in Isla Navarino, Chile, conditions could be propitious for the propagation and establishment of this parasite in local birds due to varied factors that have been unleashed in recent years.
Gregory, who is an ecologist and wildlife geneticist at the University of North Texas, presented on this issue at the recent "International Workshop on Epidemiology and Conservation: a proactive approach to avian malaria from the Cape Horn Biosphere Reserve,” organized by the Cape Horn International Center (CHIC).
"The focus of the work is to observe how the confluence of culture, climate change, and wildlife biodiversity come together to impact the emergence of avian malaria in this region and what ecological consequences they could have," says Gregory.
However, he calls for calm to the inhabitants of the southern zone, since "it is not a parasite that can survive in humans, so humans should not worry about contracting avian malaria when they arrive at Navarino Island. Nowadays, we only have to worry about birds that can contract avian malaria,” he says.
This information coincides with what was said by another speaker at the activity, the biologist, ornithologist and assistant academic at the Universidad de Magallanes, Juan Rivero. "Humans have another type of malaria, which is human malaria. It is a parasite evolutionarily related to avian malaria, but avian malaria only infects birds. There is no possibility of it infecting humans."
"What these parasites do is infect the organs, mainly the liver of birds, and from there it spreads to the circulatory system, where it infects the red and white blood cells, and they start feeding mainly on the hemoglobin in the red blood cells, which is what causes anemia in birds. It has the same effects as what happens in humans: it produces anemia, fevers, especially in young birds and susceptible species, which may even die,” adds Rivero.
The following are excerpts from an interview with Andrew Gregory last month in Puerto Williams after the close of the seminar.
PALMA: Have you been studying the possibility of malaria in birds and insects on Navarino Island?
GREGORY: Yes, for the past two years. This year will be our third research trip down here. We’ve been looking at the presence and prevalence of malaria in the birds in this region. We are also trapping insects, trying to identify which if any of the insects in the area are a vector of malaria. That’s our primary focus.
What are some of your main findings so far?
So far, we have collected many bird and insect samples. We haven't really analyzed the insect samples yet, but we have analyzed the bird samples, and we have found that numerous individuals of Rufous-collared sparrow have malaria. The interesting thing about that, this is a migratory bird, it is one of the birds that leaves Navarino Island in autumn and flies to the hotspots (areas of high presence). Then it returns here, so this bird species would probably be one of those that would bring avian malaria. It would be a malaria vector from the hotspots in Colombia or Brazil, to bring them to this region. Last year we discovered a bird with malaria that could have been recently born here.
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Gregory speaking at the Isla Navarino seminar in January.In your presentation you talked about the transmission of malaria from migratory birds, but you also warned about an event that occurred in the 1890s in Hawaii. What happened there, and why could that also happen on Navarino Island?
Yeah, great question. In the 1890s in Hawaii, whaling ships pulled into the ports, and those whaling ships, they had buckets of water that they were carrying to the sailors crossing the ocean. In those buckets of water they had mosquito larvae. When they pulled into the Hawaiian islands the mosquito larvae hacked into the islands, and settled and established, and those mosquito larvae were carrying malaria with them. And so all of a sudden, the Hawaiian islands had malaria and mosquitos, and because Hawaii is a tropical island, it’s very warm and so it’s a very good breeding habitat for mosquitos. The malaria spread from mosquitos to the birds very, very quickly. That resulted, over a prolonged period of time -- and it is still going on today -- in about a 90% or greater loss of bird biodiversity as a result of introduction of malaria to that island.
There’s a lot of similarities between Navarino Island today and Hawaii in the 1800s. Navarino Island is a very isolated place, a very pristine ecosystem, and it’s very difficult to get here. But it’s also a colder environment, so that has prevented the establishment of mosquitoes on this island. It’s also ecologically and geologically rather very young, so there were a lot of streams in the lower elevation areas. But over the last 20 years we have beavers moving into the area and they dammed up some of those streams creating some of the pools and swamps that we need for mosquito breeding to take place. Climate has warmed slightly, and as the climate has warmed we’ve crossed into this critical tipping point in mosquito development. A few years ago, it was too cool here for mosquitoes to really develop and emerge on this island, but now it’s warm enough that they can survive at high numbers. So the environment between the beavers and the climate change has changed and now Navarino Island is quite hospitable in some areas for mosquitoes. Over that same time period we have the cruise ships that are coming up and down the Beagle Channel and as humans interest in these remotes areas are at its peak, they want to go see some of these pristine places. The number of cruise ships has increased, and on the deck of those cruise ships they have things like plants and flowers and fountains for the guests to enjoy while they are cruising -- those are good places for mosquitoes and the larvae to hide. This is the one of the last harbors these ships can stop at before they make a long ocean crossing voyage and so they typically anchor here for a few days. The mosquitoes can come ashore, and now they actually find a very hospitable environment. Over the last six or so years we have mosquitoes on the island.
But how do we get malaria here? Well, that’s another part of the story that’s very interesting. We have these migratory birds like the rufous-collared sparrow, that comes from Colombia or Brazil, where malaria is very present. They migrate here duing the summer. Prior to the mosquitoes being able to find in Navarino a place to live, those rufous-collared sparrows would fly from Colombia and Brazil down here to Navarino. They live here in the summer and they go home, and if they have malaria there’s no way for the malaria to go from them to any of the local birds. Now that we have mosquitoes on the island, there’s a potential that any bird coming from that area that has malaria and comes down here, there’s potentially a vector now that could spread that malaria from those migratory birds into the residents, and if that happens, if it follows a pattern in Hawaii in which we might see a massive change in the ecosystem functionality and bird diversity.
Some of the people attending this seminar talked about how humans must have interacted when the coronavirus pandemic began. What can avian malaria teach us about the next pandemic?
It’s important to point out that malaria is caused by a parasite. Coronavirus is a virus, and they are different. So that’s an important distinction to make, but the mechanism for transmission and spread within a population is going to be very similar. And so, what we learnt about our own pandemics and how we can deal with pandemics by looking at the situation here is that we can look at the rate of transmission, we can look at the rate of spread, we can look at population dynamics that promote the spread of these infectious aegis parasites versus those that don’t. Some bird species are quite social. They interact with each other quite regularly, and those birds might have a greater spread of the parasite because they live in closer associations versus other birds that are more solitary nature. So looking at the life histories and how these different birds live and interact with each other would help us to understand how within our own populations how diseases may or may not spread and the different types of policies that we may need to put in place that would help us to limit the spread of these infectious agents when they come in. We can also look at how it can alterate the reproductive habitats behaviors and the longevity of species. Some species, the infection shortens their life-span, and changes their reproductive output and behavior. Humans like to think of themselves as being unique and outside of that circle, but we are really not. We are really subject to some of the same laws and regulations of nature and it’s interesting to look at like how some of these populations may reorganize themselves due to avian malaria here. It might give us an insight into how humans are going to respond to these pandemics as well.
How important is it to have a building like the Cape Horn Subantarctic Center for these studies in the future?
It’s very important. I cannot overemphasize how truly important it is. Having this wonderful facility here makes a lot of the research possible. It also gives us a launching point to be able to do more research, to bring additional infrastructure and support resources. We are working in one of the most remote places on Earth. It doesn’t feel that way because we are talking about a building with electricity and climate control and high-speed Internet, and we don’t take that for granted. These facilities and this infrastructure here allow us to do cutting edge state-of-the-art research to really advance the knowledge at a remote area. This area gives us an unprecedented outdoor laboratory and a look at what the world was like before humans really got to it and converted it, and so it gives us a very important baseline understanding. You know, I live in Texas, and when we measure ecological processes in Texas we are measuring things that have been disturbed, messed up, and changed over hundreds of years. Down here we have a different baseline to work from, so we can understand things a lot better.
It's like a time machine in some ways.
Yeah it is. In a very real sense. I like to tell people, you know, in Navarino Island today is like standing in Hawaii in 1891 when the whaling ships pulled in. It really is a time machine to look back in time and allow us to look at processes that we knew occurred in the past. We are been able to analyze them with more modern methods that we have so we can understand them better. And if we have a better understanding of them, we may be able to better understand and mitigate the effects of those in the future.
Our local authorities need to work better together then to confront these issues, especially in the face of the climate change that is occurring.
Yes, climate change is happening. Changes are happening. Collaboration, cooperation, are the only ways that will get us through all of this together. The things that are attracting people here are the natural resources of this environment, so we all have the same mission to take care of the Earth. To maintain these natural resources and to be able to maintain access and use of these resources for the best within ourselves, for our children. Sometimes we have different approaches, different ideas of what is the best way to do something, but the goal is the same. Collaboration and cooperation needs to prevail, and I think that is something this facility is meant to help us do.
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