Recent rainfall after a mid-summer dry spell has given mosquitoes the standing water breeding grounds they need to stage a late summer comeback. (Jon Kelvey and Max Simpson / Carroll County Times)
Steve Allgeier is sort of like a vampire hunter, although his prey and the tools of his trade are a bit different than the prototypical fictional slayer.
"Garlic and crucifixes just don't keep these bloodsuckers away," he said.
He's talking about mosquitoes, of course. Recent rainfall after a mid-summer dry spell has given those winged nuisances the standing water they need to breed and stage a late summer comeback, according to Allgeier.
As a horticulturist with the University of Maryland Extension Office in Carroll County, Allgeier often receives calls from people concerned about ticks or bed bugs, but recent headlines about the mosquito-borne Zika virus have led to Allgeier receiving a lot more phone calls about the buzzing blood suckers.
Consequently, he's launching a series of talks, beginning Sept. 8 and running through most of September, that will address how to reduce the probability of being bitten "by taking a few simple steps around your landscape and also personal protection you can incorporate into your own routine."
Monday marks the beginning of Zika Awareness Week as proclaimed by Gov. Larry Hogan, and state and local health officials are reaching out to inform the public about the risks of Zika , as well as simple actions to mitigate those risks.
Joining Allgeier at each talk will be one or more members of the Carroll County Health Department, according to Deputy County Health Officer Dr. Henry Taylor. While Allgeier will address mosquitoes, their biology and how to mitigate their presence and vampiric habits, staff from the Health Department will address the diseases mosquitoes can carry, Taylor said, which includes diseases that are endemic to Maryland and Zika, which is not.
"In the broad picture, there are a number of mosquito-borne illnesses, West Nile would be the most common. There are other types of rare encephalitis that we see more on the Eastern Shore," Taylor said. "It's helpful to think about these diseases as those that occur locally, and that you acquire locally, as opposed to mosquito borne-illnesses acquired by travelers."
While numerous states have reported cases of Zika to the Centers for Disease Control and Prevention — Maryland has reported 85 cases — these are almost exclusively attributed to people who have traveled to countries where Zika is endemic, such as Brazil. Only Florida has recorded local transmission of Zika, either through mosquitoes or sexual contact with infected persons.
"We have to test people who are symptomatic and who have traveled in order to see if Zika is spreading," said Maggie Kunz, coordinator of special services at the Health Department.
People can contact their own doctors or call the Health Department and speak with a communicable disease nurse if they have questions about getting tested for Zika, she said.
The thing about Zika, however, is that there is still a lot that scientists do not know, according to Kunz, and there is no vaccine or prophylactic medication that someone can take as with, say, malaria. Because that is the case, and because there are other mosquito-borne illnesses in Maryland such as West Nile, the Health Department, like Allgeier, is also focusing on the message of preventing mosquitoes from breeding and biting in the first place, Kunz said.
"Mosquito bites are just pretty darn unpleasant," she said. "They are annoying to have in general, so there is no harm in taking extra steps to avoid mosquito bites."
In Westminster's Belle Grove Square, Allgeier demonstrated how he stalks mosquitoes armed with a turkey baster, a plastic water bottle and a bottle of insect repellent.
"When we talk about mosquitoes, a lot of people think we can just spray them to death. We'll get out some foggers and misters or area sprays, and spray everywhere," Allgeier said.
Instead, Allgeier said, you have to hunt down the places where mosquitoes can breed.
"That means dumping out standing water and little areas that contain water, making sure that they drain freely or that they do not fill up with water at all," he said.
That includes depressions and hollows in trees on a property. Allgeier demonstrated how to use a turkey baster to probe a hole in a cherry tree in Belle Grove square, sucking up any liquid that might be contained and squirting it into a plastic bottle to see if there are any squirming mosquito larvae.
"They call them wrigglers or wigglers depending on who you talk to," he said. "Give them four to five days with adequate temperature and many of them start to hatch. Then if you are really good and you have really strong eyes, you can start to identify them."
Of particular concern is the Asian tiger mosquito. An invasive species, the Asian tiger is small even for a mosquito, has striped legs, is active during the day as well as the mornings and evenings and is an aggressive biter, according to Allgeier. It is also capable of transmitting Zika, should the virus take hold in Maryland, he said, but of greater concern is its ability to breed in next to no water.
"I was talking with the Maryland Department of Agriculture the other day and they found seven ... Asian tiger mosquito larvae in a bottle cap filled with water," he said.
Emptying out water that can be dumped, ensuring containers can drain or applying a larvicide "dunk," available at most hardware stores, to a body of water are the best ways to keep mosquitoes from becoming a problem in the first place, according to Allgeier.
Zika is not the first mosquito-borne illness for which there is no vaccine to threaten portions of the United States. According to Taylor, the patterns being seen in Zika hearken back to the late 19th and early 20th century, when the mosquito-borne yellow fever not only imperiled the construction of the Panama Canal, but struck with often fatal results close to home.
"Yellow fever was endemic in the Baltimore area, and Carroll County would have had some cases," he said. "It just so happens Zika is in one of those mosquitoes about which we did all the research. That knowledge is being brought forward. We haven't forgotten it."
A student of the history of public health as well as a practitioner, Taylor has a collection of medical records and publications from era of yellow fever. In a 1911 tract entitled "Yellow Fever," public health and military officials at the turn of the 20th century describe how they recognized the "the dangers of allowing wrigglers on their premises," and their discovery that "the spread of Yellow Fever can be most effectually controlled by measures directed to the destruction of mosquitoes and the protection of the sick against the bites of those insects."
In the early 1900s, that meant covering rain barrels and draining swamps and wetlands. In 2016, people in Carroll County have a leg up on the people who built the Panama Canal — DEET.
Allgeier called it the most effective, proven mosquito repellent available.
"DEET is still considered the gold standard after all the testing, and it's been around for a long time, since the 1940s," he said. "The military has used it, and there is a lot of evidence that DEET is extremely safe and extremely effective."
There has been interest in non-DEET natural products such as eucalyptus oil, which Allgeier said does work to some extent, but not as well or as long as a repellent containing DEET. He warned against using a repellent that hasn't been tested for effectiveness and is happy to provide people with information on repellents that work, either at one of his upcoming talks or by phone or email.
"When there is a new problem out, it's usually room for snake oil," he said. "Please look for reliable resources — I work for the University of Maryland. You can call me or email me, my email is email@example.com."
More information on controlling mosquitoes to prevent any potential transmission of Zika, West Nile or other illnesses can be found on the Carroll County Health Department's "Fight the Bite" page, cchd.maryland.gov/Zika, by calling the department's Environmental Health Bureau at 410-876-1884 or by contacting Steve Allgeier at 410-386-2760.