This post marks the completion of my first week working as an Intern at MaineHealth’s Lyme & Vector-Borne Disease Laboratory. Through this week I was exposed to a variety of methods and data preparation processes. On my first day here I was made aware that, accessioning is everything! What this boils down to is, properly matching samples collected in the field, with corresponding paperwork that will later be entered into a data base. While I have not been introduced to data entry, I have been shown the many ways that if prepared incorrectly or missing information, there may be confusion. Additionally, much of this week has been dedicated to learning how to identify species of mosquitos. I have received a dichotomous key that helps narrow down the identification from genus to species. However, what is most exciting to write about is my week as it pertains to surveillance. This post will dive into my day-to-day experiences touching on both tick and mosquito surveillance, a little on tick life cycles and medical importance, current public health concerns in Maine, and pictures documenting my week. I hope you enjoy!
To start the week off, I was fortunate enough to be taken onto 2 surveillance sites to “flag” for ticks. “Flagging” I soon learned is a common practice when it comes to tick surveillance. To participate you have to have a "flag". It is essentially comprised of a corduroy or flannel material attached to a stick, which in my case was made out of bamboo. By swiping this so-called flag along the ground, questing ticks may be likely to grab hold, as this material simulates a person brushing by. This method can be very successful but dependents many factors such as, temperature, weather conditions, ground conditions, wind speed, and even humidity can potentially play a role. The two sites that I visited on Monday were both considered “mixed forest” as there are portions of the woods that are both deciduous and coniferous. Before beginning to attempt to collect ticks, it was important to properly don PPE in order to protect myself. I was given a white painters jumpsuit that is helpful since it is a light color, so if I found a tick on my body it is easier to spot. Additionally bug spray can be very useful when doing this type of surveillance work as other insects, including mosquitos, are likely to be attracted to you. On this day, between both sites, I flagged for a total of 2 hours, 4,249 meters, and found only 8 ticks. Now, that is not a substantial number of ticks for the time walked and distance traveled, but a great introduction to the method and an introduction to the species of ticks captured.
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| Flagging for ticks at Ida Jim Road, Alfred, ME The next day was fairly busy. The accessioning I alluded to in the beginning of this post came into play as it was time to record my efforts in tick surveillance from the day before. Ticks are generally easier to identify, as this can primarily be done on a macroscopic level, whereas mosquitos typical require use of a microscope. |
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| Dog Ticks (Dermacentor variabilis) in a collection vial with ethanol |
In the state surveillance project that I am working on, the goal is to collect as many nymphs as possible. A nymph is a stage in the tick life cycle that was explained to me as “teenage” in a way. After eggs are laid and have hatched, the first stage of the cycle is larva. This life stage is typically of least concern as the larva have not taken a bloodmeal yet, so they in theory, do not hold disease pathogens. The larva can be differentiated from the other life stages by their legs. Larvae have 6 legs in total whereas nymphs and adults have 8. Once the first bloodmeal is taken, the larva will develop into a nymph. This life stage is incredibly small and can be compared to the size of a poppy seed. This life stage is of the greatest concern in Maine as they are very active in the summer months, can cause disease, and are very difficult to see. Since they are difficult to see, they may be able to bite an unknowing person or animal and transfer disease. A second bloodmeal initiates the development to the adult life stage, and while this life stage is still medically important, they are at the end of their life cycle. Disease can still be spread, but these ticks are easier to spot and often easier to feel crawling on the body before a bite occurs.
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| Tick life stages, Photo Credit, CDC |
With that all being said, there is also a medical importance scale of tick species. From my collection on Monday, I had found 5 female dog ticks (Dermacentor variabilis), 3 male dog ticks. While this is still useful, there is another tick species that is medically more important to Maine at this moment. One of the most diverse vectors in Maine is the deer tick, Ixodes scapularis. This species has been known to transmit the diseases of Lyme, Anaplasmosis, Babesiosis, and Powassan Encephalitis. So while it is important to collect and perform surveillance on D. variabilis, finding I. scapularis ticks, and even better I. scapularis nymphs, are more beneficial from a public health standpoint.
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| Resting box collection tool |
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| Light + CO2 mosquito trap |
As the day pushed forward further worked on mosquito identification. On the day previous I had worked on distinguishing different species of the genus Anopheles. I had now began to become familiar with Aedes genus mosquitos, which would become a great foundation for opportunities that followed later in the week. To cap off the end of a great Tuesday, I was able to go into the field again, but this time with mosquitos in mind. Heading up to Cape Elizabeth, Maine, I would join a research assistant from the lab to set up and collect from various mosquito traps. First I was able to collect mosquitos from what are called “resting boxes”. These black boxes are set up in shaded areas and imitate a log in the woods. Mosquitos rest in the inside of these boxes and by using an aspirating tool it is possible to collect them. The tool that was used, shown above, is an aspirator hooked up to a plastic collection container with a wide horn like opening. This is pointed into the resting box, making sure to not cast a shadow or walk directing in front of the box before, and pulls mosquitos inside to the collection container. We had some success in this method, but ending the day collecting from resting boxes is typically not the best time. This method is most successful before 10 AM as the temperature is still gradually rising. Lastly we set up a light + CO2 trap that would be checked in the morning at about 9:30 AM. This trap is pretty self-explanatory as the name implies. CO2 is produced by using dry ice, the dry ice sublimates, and the gas is released to the air. Mosquitos are drawn to CO2, so this pulls them into the trap. There is a fan actively pumping in this trap that keeps the mosquitos captured from being able to escape.
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| Resting box collection |
Wednesday slowed down a bit. I had returned to Cape Elizabeth to collect mosquitos from the light + CO2 trap. This was brought back to the lab, accessioned, and placed into the freezer to await identification. I received a formal lecture from my research mentor on the life cycle, morphology, and public health/veterinary health concerns involved with tick species in Maine. And to finish off the day I was able to continue to practice my mosquito identification skills by assisting in ID’s of previously accessioned specimens so that they would be ready to send to the State Laboratory.
Thursday had a different pace and was a super exciting opportunity. I was able to attend an Orono Arboviral Town Hall hosted by the Maine CDC. While here I was able to hear expert insight from 7 members of the Maine public health community on preparing for arboviral activity for the upcoming season. This panel included Charles “Chuck” Lubelczyk, MPH (my research mentor) a vector ecologist, Haris Sohail, an infectious disease epidemiologist, Rachel Fiske, a veterinarian, Megan Porter, DVM, a health educator, Gary Fish, integrated pest management, Alexander Peacock, pesticides and mosquito control, and Michael Morrison, and aquatic entomologist and mosquito control contractor. This group of experts relayed information on life span, morphology, surveillance methods, prevention methods, intervention, and epidemiological data for incidence of 3 arboviral concerns in Maine. These are identified as Eastern Equine Encephalitis (EEE or tipple E), Jamestown Canyon Virus (JCV), and West Nile Virus (WNV).
Through the presentations some of my key takeaways were that there has been 2 human cases of EEE in Maine since 2014, 4 cases of JCV, and 5 cases of WNV since 2005 (all of which being non-fatal). Strikingly there have been numerous reported animal cases of EEE and WNV within the last year, prompting concerns that 2024 may be a bad year for arboviral activity. Rachel Fiske reported that EEE was detected in 16 animal cases in 2023, and 0 in 2022. WNV has 1 animal case in 2023 and 0 in 2022. This means that while we have not seen large amounts of arboviral activity in humans, these viruses are still around and have been infecting livestock and farm animals. The substantial incidence of EEE in 2023 has sparked concerns all around the state to be diligent and preventative to prepare for the upcoming arboviral season. This town hall was gaged to inform those working in public health and the community on the steps that can be taken to prevent human transmission. Megan Porter explained that it is best to avoid being outdoors at dusk and dawn respectively because that is when mosquitos are most active. To always wear protective clothing and use EPA certified bug sprays where the active ingredient is known to repel mosquitos. And if a person will be consistently exposed to high-risk outdoor activities, to treat their clothes with permethrin. This was an incredible opportunity to hear from some of the states leading experts in vector-borne disease and learn about the types of work they perform to contribute to making Maine as safe and healthy as it can be.
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| View from Runaround Pond, Durham, Maine |
The week was finished by another trip outside of the lab to flag for ticks in two new sites. Range Pond State Park in Poland and Runaround Pond in Durham, will be two sites that I will be visiting regularly to work on tick surveillance. While the conditions were rainy and not the best for flagging, I was able to collect a singular female adult deer tick (I. scapularis).
This first week was jam-packed with information, learning, note-taking, and networking. I had a blast in all the activities that I was tasked with completing. I am excited to provide this dense blog post to you all and continue to update and inform on my weeks as an intern at a vector-borne disease lab!
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| Map of places visited this week |
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