By Kellie Britch, College of Arts and Sciences
Santiago-Alarcon's lab consists of undergraduate, graduate and doctoral students. (Photo by Corey Lepak)
With diseases like malaria showing up in subtropical areas such as Florida and Texas,
preventative research is more important than ever. Diego Santiago-Alarcon, an assistant professor in the Department of Integrative Biology and expert in disease ecology, does just that. Santiago-Alarcon has discovered changes
in the diversity and transmission of mosquito-borne pathogens carried by birds due
to human activities.
“We are trying to get a better understanding of how human activities, in particular
the urbanization process and land use changes, affect the probability of the transmission
of pathogens,” Santiago-Alarcon said. “In other words, we’re trying to identify the
factors within those human activities that increase or decrease the probability of
transmission of diseases, such as mosquito-borne blood parasites like malaria.”
Through his research, Santiago-Alarcon has found that not all parasites are equal,
even when they are closely related.
“The parasite world is huge and diverse, making it very difficult to make broad generalizations
of the outcomes that you can expect across different types of parasites in response
to the same environmental factors,” Santiago-Alarcon added. “What you detect as increasing
the probability of transmission for one parasite group might decrease the probability
for that parasite’s cousin.”
According to Santiago-Alarcon, organisms are developing genetic variations to adapt
to the extreme changes in urban and rural conditions. In order to better understand
and share the factors that are influencing the evolution of these organisms, he is
working to build an urbanization gradient for Hillsborough County by mist netting
birds in areas with varying degrees of greenness and development. Part of this work
is happening in the USF Forest Preserve, which is a green site across the urban gradient for this project.
Once they have the birds, Santiago-Alarcon and his students identify the species,
take measurements and secure a blood sample before banding and releasing the birds.
The blood samples are used to determine whether the bird is infected with a blood
parasite.
After catching a bird, Santiago-Alarcon takes morphological measurements as well as a blood sample. They then place a metal band on the bird’s leg and release them back into the wild. (Photo by Corey Lepak)
The blood samples are taken to the lab where Santiago-Alarcon and his team do molecular and microscopy work to determine if the bird is infected with parasites. (Photo by Corey Lepak)
“If they are infected, we sequence a mitochondrial gene from the parasite which we
use as a barcode, and that barcode is going to tell us the genetic variant of the
parasite that we are dealing with,” Santiago-Alarcon explained. “By using microscopy,
we can also tell what stage in the life cycle the parasite is at and whether it could
be picked up by a mosquito, for example.”
The hope is this research will not only give the broader public valuable information
but also allow city planners and other officials to evaluate the effects of development
on disease transmission and then refine those practices.
“Our study is the first to collect bird census data at a fine scale within an urban
landscape in Florida and to assess birds' health across an urban gradient in the state,”
said Harikrishnan Cherayi Padinjakkara, a third-year doctoral student in Santiago-Alarcon's
lab. “This research will provide valuable insights into urban planning practices in
Florida by investigating the impacts of urbanization on bird populations and the transmission
dynamics of parasites.”
Learn more about Santiago-Alarcon's research.