5 Questions with Faculty: Biomedical Sciences Assistant Professor Alexander T. Ciota

Assistant Professor Alexander T. Ciota is Director of the Arbovirus Laboratory at the New York State Department of Health’s Wadsworth Center, which performs testing, surveillance and research of arthropod-borne viruses (arboviruses). The lab studies both mosquito and tick-borne agents including the flaviviruses West Nile virus, Zika virus, dengue virus, St. Louis encephalitis virus and Powassan virus, as well as alphaviruses eastern equine encephalitis virus and chikungunya virus, among others.  

Have there been more cases of infection from vector-borne pathogens in recent years? If so, why?

Yes. Prior to emergence of the novel coronavirus in the U.S., the steepest increase in infectious diseases in the last two decades was associated with vector-borne pathogens.

There are many reasons for this: A larger global population and an increase in travel and transport increases host availability for vectors and facilitates introductions and spread of exotic pathogens; increased invasion of previously undisturbed or sparsely populated regions increases the probability of spillover to urban populations, climate change alters the geographic range of hosts and vectors, warmer temperatures generally create conditions which facilitate more efficient transmission of vector-borne pathogens and longer transmission seasons.

Do the viruses mutate and what does this mean for transmission and human infection?

Arthropod-borne viruses (arboviruses), which are transmitted by mosquitoes, ticks and other blood sucking insects, almost exclusively use RNA as their genetic material. These viruses lack proofreading mechanisms to repair errors made during replication of their genomes. They additionally replicate rapidly and to high levels, resulting in an abundance of genetic variation.

 As a rough estimate, most arboviruses acquire one new mutation every time they make a copy of themselves. Considering they can create over a million new copies during a single infection of a host or a vector, it is easy to imagine how quickly these viruses can diversify and adapt.

While most mutations are deleterious to the virus and others have no measurable effect, a minority will alter infectiousness, host range, replication rate, transmissibility and virulence. There are a number of examples of even single mutations having significant public health consequences.

What factors shape patterns of arbovirus transmission?

Predicting patterns of transmission of mosquito and tick-borne viruses is complicated. This is because these are highly complex and dynamic transmission cycles. These genetically diverse viruses interact differently with diverse hosts and vectors, and these unique interactions determine how well each virus infects and is transmitted by each host or vector.

In addition, vectors need to feed on an infected host and survive long enough to be able to transmit to another host, so the fitness of the vector and extent of contact it has with hosts is critical. This is highly influenced by environmental factors, particularly temperature and precipitation.

Lastly, while some invasive exotic viruses like dengue virus and Zika virus utilize humans as primary hosts, mosquito-borne viruses endemic to New York State, like West Nile virus and eastern equine encephalitis virus, are maintained in nature in cycles between mosquitoes and birds, with humans being incidental hosts. So, for these viruses we need to additionally consider the complexity of avian ecology and disease, and the influence of the environment on host factors.

Can you tell us about your research at the Arbovirus Laboratory of the Wadsworth Center?

Our facilities include biosafety level 2 and 3 virology labs, arthropod containment labs and animal labs. This allows us to work with the majority of exotic and endemic arbovirus in a range of systems. We currently have 15 unique mosquito populations that we maintain in the lab. We also have extensive equipment and expertise in virology and viral genetics.

My research questions are broad, but I have historically focused on evolutionary biology and vector-virus interactions. In addition to studying natural evolution of arboviruses, we’ve utilized experimental evolution in the lab to better understand the genetic signatures associated with transmission, host range expansion and virulence.

For many of the viruses we study, we have the ability to manipulate the genome. This allows us to directly study the impact of mutations we identify. I am particularly interested in how diverse swarms of viruses and other microbes co-exist and interact within hosts and vectors. Much of our recent research has focused on understanding the role of temperature in arbovirus evolution and transmission. We simulate temperature changes in the lab and evaluate how this influences viral genetics, transmission and mosquito fitness in unique populations.    

How do the studies in your lab inform public health decisions in New York?

In addition to research, The NYS Arbovirus Laboratory is responsible for confirmatory diagnostic testing and arbovirus surveillance. Surveillance includes annual testing of thousands of mosquito, tick and vertebrate samples submitted by state and local health departments.

Our testing and research objectives very much complement each other. We study how well populations of mosquitoes in New York can transmit potentially invasive viruses. When we identify new pathogens or new strains of endemic viruses through our surveillance program, we characterize them to better define the threat of transmission and disease. Our studies of temperature inform disease models to help us predict how climate change is impacting risk in different regions.  

Lastly, the long-term goal of many of our research projects is to inform novel strategies for both vector control and therapeutics.