Mosquitoes, Graveyards and Science, Oh My!

By Kathryn Cannon

Research is formalized curiosity. It is poking and prying with a purpose. -Zora Neale Hurston

While walking through a graveyard, you wouldn’t think to look for insects known to suck human blood. However, that is precisely what Dr. Christofferson and her graduate assistant Ania do. They will go into a graveyard looking for a certain wild type of mosquito, A. albopictus. These mosquitoes love to feed and breed in the dirtiest water they can find. Where better to search than a graveyard full of dirt, decaying leaves and water collected in the vases located by headstones? This kind of environment is where they thrive and the perfect place for Dr. Christofferson to collect specimens for her research.

On September 18, 2015, I had the privilege of shadowing Dr. Christofferson a professor and researcher at LSU. I went for a day to see how she conducts her field research and lab work. Dr. Christofferson said, “I am interested in population level hypotheses.” She looks at transmission. She studies various factors that affect whether or not the transmission of a virus to humans will be successful or unsuccessful and whether the virility of the virus will increase in intensity or decrease in intensity. She also looks at how the virus affects the mosquitoes she exposes. For example how long will it take them to become infected, how many become infected and how long do they live afterwards etc. She explains how she looks at the dynamics of the virus in the population.

Field Research

Field Research Photo Credit :Katie Cannon

We arrived at the Baton Rouge graveyard to collect specimens they will need for lab studies. It was a pretty day to be outside considering how hot Louisiana’s weather normally is around this time of year. Another student and I observed as Dr. Christofferson and Ania started looking for larvae and pupae in the vases located at the gravestones. They would use a pipette to suck up a water sample to see if any larva or pupa were present. Ania and Dr. Christofferson were so enthusiastic when they found a vase full of mosquito specimens.

Ania expressed her enjoyment by saying, “Oh so many!” several times throughout the day; she had a “the more the merrier” mentality. Dr. Christofferson mainly uses two main locations for her samples, a cemetery in Baton Rouge and several locations in New Orleans. Every once in a while she will include Lafayette. She collects two different types of mosquitoes from the wild. The Baton Rouge graveyard mosquito is A. albopictus and the New Orleans mosquito is Aedes aegypti.

In the bottom of one vase Dr. Christofferson found a frog and was very enthusiastic about it. She kept saying “Better than teeth.” She was referring to the time they went to a New Orleans graveyard where they found a set of denture teeth. Oh the things you can potentially find while conducting field research! In the video below you can see her reaction to finding the frog. This is exactly why Dr. Christofferson loves to be in the graveyards looking for insects.

Sorting Mosquito Specimens Photo Credit: Katie Cannon

Sorting Mosquito Specimens
Photo Credit: Katie Cannon

After we filled up a couple buckets of specimens we were ready to head back to the lab. The Biosafety Level 2 lab is where they keep the larva and pupa stages. Once they emerge into an adult the mosquitoes will be moved into another lab. The lab looks just like any other lab I have been in. It has the microscopes, supplies, and instruments they need. I did notice there was a constant humming noise coming from one of the machines. When we entered the Biosafety Level 2 lab Dr. Christofferson said, “Let’s get this party started.” We then began the sorting process. The larvae went in one container and the pupae in the other. Right when Dr. Christofferson turned on the radio the “Wiggle” song by Jason Derulo ft. Snoop Dogg came on. According to Dr. Christofferson it is their larva song and she cranked up the radio.

After the specimens are separated they keep the left over “dead people water” for about five days in case there are more larvae they potentially missed. Sometimes they are not visible to the naked eye until after they reach a certain point. I asked why they call it “dead people water.” Dr. Christofferson and Ania both started laughing. Ania told me, “Just because we got it in a graveyard.” Dr. Christofferson made the comment, “And it stinks like dead people.” Everyone started laughing. Dr. Christofferson’s enjoyment is evident in her research and her enthusiasm is contagious.

Labeling Photo Credit: Katie Cannon

Labeling Photo Credit: Katie Cannon

Ania demonstrated what they do with the larvae and pupae after separating them. She took out a pan in the refrigerator that the larvae are kept in until the pupa stage. The pupas are put into a container with a screen placed over it and a hole cut into the top to add more pupas once they are developed from the larva stage. She will label the container with information from where they collected the specimens, the date and their generation. Ania said, “The more generations they spend in the lab the less they are like whatever is in the field; so you have to keep track of that.” Ania commented, “The process goes faster with four people.” I can believe that. While trying to separate the larvae from the pupae I kept commenting how fast they move. They twitch this way and that way. Below is video footage of just what I mean.

Mosquitoes hatch from eggs and they molt three times in a process called instars. They will then form into a pupa and after 2-3 days they will emerge from the aquatic stage as an adult. If the mosquito gets its wings wet after emerging, it is doomed from the beginning. A mosquito can live around 18 days depending on temperature, humidity and other factors in the wild. In the lab they can live up to a month because everything is controlled. If you have felt a mosquito bite your arm and squished it with blood coming out as a result you killed a female. Only females will bite a human for the blood source, males need only nectar.

Dr. Christofferson teaching Photo Credit: Katie Cannon

Dr. Christofferson teaching
Photo Credit: Katie Cannon

I asked Ania how she liked conducting this type of research. She said, “Its supper fun. I love it! It reminds me of when I was a kid at the beach and I would find little ponds of seawater with crabs and fish. I would collect them in a bucket.” An interesting fact I learned from Dr. Christofferson was how to tell the males from the females. A researcher can tell the males by how their antennas look like bunny ears and how fluffy they are. Females are not so fluffy and after females feed they sit on the wall like a fly. Dr. Christofferson started saying, “Help me, help me,” in a sing song voice. She said, “Y’all were too young for that.” I asked, “To young for what?” She said, “The Fly.” I asked, “The movie?” She said, “Yeah!” I said, “Oh no, I am not too young I saw it.”

Once the mosquitoes reach adulthood they are transferred to the Biosafety Level 3 lab. I was unable to view the lab due to regulations. Each infectious agent has been labeled by the USDA or CDC as one of four levels. Level 3 and above need to be in a regulated lab with minimal traffic and follow regulations set by the CDC. The CDC is one of the major operating components of the Department of Health and Human Services. Dr. Christofferson explained, “Because we catch our own mosquitoes in the wild we go ahead and do our infected work in the BSL3 as an extra precaution just because if they got out they could potentially cause a viral outbreak.” In the BSL 3 lab they have to wear a full hazmat suit to help prevent contraction of any disease.

One would not think mosquitoes could be interesting. However, getting hands-on experience I can say personally it was a rewarding and extremely fun day. Dr. Christofferson and her graduate assistant Ania brought humor and passion to a serious study that benefits the human population. Scientific research is a balance between field work and the lab. When you bring the fun out in science anything can become interesting to the average person including mosquitoes.

Below is a slide show of all the pictures I took:

Dr. Christofferson has a webpage describing some of her work. http://www.epiresponse.com/#!about-arboviruses/c1cn3

Links:

http://www.cdc.gov/about/organization/cio.htm

http://www.cdc.gov/dengue/resources/30Jan2012/comparisondenguevectors.pdf

You tube: https://www.youtube.com/watch?v=hiP14ED28CA

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