By Katherine Unger Baillie
Forget birthstones and astrological signs; the month in which you were born may carry serious significance for your health.
A research project involving a team from Penn’s Perelman School of Medicine and School of Veterinary Medicine is teasing out a link between birth month and cardiac disease risk, looking at both humans and dogs. The main thrust: Being born in the summer heightens the risk of disease later in life.
“Dogs are more similar to humans than many other animal models,” says Mary Regina Boland, a biostatistician at Penn Medicine. “They’re pets, so they live in the same environment as we do, but they also can naturally develop cardiovascular disease.”
Boland had been examining the link between birth month and heart disease for a few years, relying on electronic health records, but encountered challenges when accounting for biases and disparities reflected in the data. So she turned to another source.
“I started wondering whether there were any animal models that could potentially support this,” Boland says.
Exploring datasets for pet dogs, Boland realized she needed colleagues in the veterinary world to help her navigate. She connected with two veterinary cardiologists at Penn Vet, Anna Gelzer and Marc Kraus. Together, they analyzed datasets from Penn Vet and the Orthopedic Foundation for Animals, an organization that supports research on inherited diseases in pets.
In a study published earlier this year in Scientific Reports, Boland, Gelzer, Kraus, and colleagues found a strong link between birth month and cardiac disease risk in canines: Those born in the summer months were predisposed to developing heart problems, with the risk soaring up to 74 percent higher than expected for dogs born in July.
In that work, as well as prior studies using human health records, researchers pointed fingers at air pollution as a likely culprit for this connection. It’s believed that exposure to fine air particulates—which are at their highest levels in the summer—somehow leads to harmful physiological changes in utero that may not manifest for decades.
Dogs prove a useful parallel subject to humans for these sorts of studies, the researchers note. “Their life spans are shorter, so if they’re going to develop a condition it will show up in a reasonably compressed timeframe compared to humans,” says Kraus.
That project is still in its early stages, but could have a variety of implications for reducing disease risk.
“For dog breeders, it’s pretty easy to control when puppies are born,” says Gelzer. “With June and July having the highest risk for heart disease, we could just advise to breed during months that wouldn’t result in these birthdays.”
When it comes to humans, dictating which month a baby will come into the world is not as straightforward, but insights gleaned from research in dogs have the potential to help uncover the molecular mechanisms that lead to birth-month effects.
For now, the Penn researchers are brainstorming ways to explore those mechanisms, such as statistical deep dives, genomic sequencing, or microbiome analyses, to potentially locate new intervention targets. They’ve also recently begun to explore connections between cancer risk and birth month, collaborating with Penn Vet’s Nicola Mason, a clinician and researcher who has applied immunotherapy approaches to treating cancer in dogs.
“This doesn’t mean there shouldn’t be any more summer babies,” Boland says, “but the findings we generate could be an entry into some very interesting questions about the drivers of these connections.”
In a recent study, researchers used 19 human stressors to determine what marine wilderness was left in the world. They call for large-scale actions to protect these areas, including preventing overfishing and limiting run-off from land-based activities.
By Michele Berger
Our weekly round-up compiles stories and news, both from here at Penn and around the world, that highlight the intersection of animal, environmental, and human health.
The last of the ocean wilderness
Scientific American, July 26, 2018
In a number once unimaginable, today just 13 percent—21 million square miles—of the world’s oceans remain untouched by humans, according to a study published in Current Biology. So far, large-scale international environmental policies have failed to protect these as-yet uncharted waters.
Could this tiny spider be helping the Arctic stay cool?
Science, July 23, 2018
Wolf spiders typically eat an insect called the springtail, whose diet is composed of fungi in the soil that release carbon dioxide and other potent greenhouse gases. But when the temperatures spike, the spiders eat each other instead, inadvertently allowing more of these gases to enter the atmosphere over the Arctic.
For the first time, a female Ebola survivor infects others
The New York Times, July 23, 2018
For more than a year, the Ebola virus hid out in the body of a woman who had survived the infection during the epidemic in West Africa. When she relapsed, the virus was still contagious, the first known case of this type.
The world is hot, on fire, and flooding. Climate change is here.
Grist, July 24, 2018
The headline kind of says it all: As droughts and heat waves amp up both in frequency and intensity, fires are happening more often. More intense rains are causing flooding around the world. Plus, it’s already one of the hottest years on record—and we haven’t even hit August.
Top EU court: GMO rules cover plant gene editing technique
Reuters, July 25, 2018
The Court of Justice of the European Union decided that plants that have undergone gene editing called mutagenesis fall under the same laws as other genetically modified organisms, a boon for environmental advocates but a setback for the biotech industry.
New drug wipes out malaria in a single dose—but there’s one hitch
NPR’s Goats and Soda, July 26, 2018
A new drug called tafenoquine is extremely effective at wiping out malaria, preventing relapse by as much as 70 percent. But to use it, health care providers must administer a test that determines whether someone’s red blood cells will respond poorly to it, an expensive diagnostic that’s not yet widely available.
Michele Berger is a Science News Officer in University Communications and chair of the One Health group.
Barbecue season is in full swing. Though some may prefer meatless options, summertime staples like hot dogs and hamburgers still occupy a good bit of paper plate real estate. In fact, July has been named National Hot Dog Month by the National Hot Dog and Sausage Council, with July 18 marking this year’s National Hot Dog Day.
While these classics have been the centerpiece of many American BBQs for decades, the harsh reality is that they remain some of the unhealthiest choices.
“Eating foods that are highly processed, high in fat, and high in sodium, such as hot dogs, ground beef, and the toppings used to dress them, can impact one’s risk for heart disease and diabetes, among other diseases,” said Helene Glassberg, an associate professor of cardiovascular medicine at the Perelman School of Medicine. “While enjoying these foods occasionally may not put you at an increased risk, frequent consumption, coupled with other risk factors such as obesity, sedentary lifestyle, and genetics, can quicken the onset of these life-threatening diseases.”
Despite these known risks coming from clinicians, and data from organizations such as the World Health Organizations (WHO), which reported in 2015 that processed meat was linked to an increase in cancer risk, these items are not likely to disappear from party menus. So while moderation is king, here Penn experts in nutrition dissect some typical barbecue fare.
“Eggs have generally been given a bad rap for their cholesterol, but the truth is they are actually quite healthy,” Glassberg says. “They only have 80 calories, of course with some fat, but very little carbs, lots of vitamins and minerals, and great protein. But for some, the amount of cholesterol found in eggs can be an issue.”
Those with higher-than-normal cholesterol levels, a history of heart disease, or who are already taking medications to treat a cardiovascular condition should steer clear of these. Glassberg says that for the most part, “there is a limit to how much direct cholesterol we absorb in our diet, so I generally support egg consumption. But deviled eggs, on the other hand, they’re another story.”
If made the traditional way, these bite-sized snacks are very high in fat and calories, from the added mayonnaise and mustard. More creative recipes even call for cheddar cheese and bacon (more on that later), which really put these snacks on the bad list. Fear not, Glassberg says. “If you decrease the number of yolks used—say, if you make 12 eggs but only use the yolks from six—and replace the mayonnaise with non-fat Greek yogurt, these can still be a healthy summer snack.” All in all, when slightly modified, these snacks are a keeper.
Corn on the cob
This one can go either way, depending on how it’s eaten. “Corn on the cob by itself can be a healthy choice, but the problem arises [with] toppings,” says Colleen Tewksbury, program manager for the Penn Bariatric Surgery Program. “Typically butter, salt, or cheese are added, which bring unnecessary calories, sodium, and added fats to the plate.”
Tewksbury and folks in the Bariatric Surgery Program work with patients on the road to bariatric surgery to make adjustments in their eating habits and approach to food to set them up for success following the procedure. Many patients start logging their food as part of the pre-surgery steps, either with pen and paper or with apps such as My Fitness Pal or the newly launched Penn Life Gained, designed to streamline tracking steps and exercise, recording caloric and water intake, monitoring sleep time, altering diet, etc. for patients undergoing bariatric surgery.
Many of these adjustments also focus on planning ahead for events or parties, so patients can think about what they will eat, prepare to avoid certain items, and plan out their days prior to account for the foods served at parties. Corn alone is high in fiber, and is a good source of vitamins and minerals, but it’s definitely a slippery slope when toppings are involved. “When in doubt, keep it plain,” Tewksbury says.
“These may sound like they are a good option to gravitate toward since beans are typically seen as good sources of fiber and protein, but baked beans are often very high in sugar and calories,” Tewksbury says. “The sugar and molasses in the sauce take this protein- and fiber-rich item, and turn it into something more akin to a dessert. At the end of the day, the benefits from the beans may not be worth all of the additional calories.”
The issue of sugar in traditional BBQ fare is one that William Duffy, an internal medicine specialist at Penn, discussed with Men’s Health earlier this month. Duffy stressed the importance of avoiding store-bought dressings and rubs, which can be high in sugar, just like store-bought (or even homemade) baked beans, which can pack up to 12 grams of sugar in just one half cup.
To put this in perspective, according to the American Heart Association, the average male should consume no more than 36 grams of sugar a day, and the average woman, no more than 25 grams. With that scale, one serving of baked beans could amount to half of a woman’s daily sugar limit. In this case, Tewksbury urges portion control, especially if sweets will hit the table at the end of the barbecue.
Pasta and potato salad
These sides are also a bit tricky. “The calories in pasta or potato salad tend to add up quickly, particularly for such a small side dish,” Tewksbury says. “One cup of either salad can be more than 350 calories, which can raise the total calorie content of a meal rapidly.”
In addition to the calorie counts, much like with deviled eggs, the addition of “hidden” ingredients like mayonnaise can put this side dish is the “not so healthy” bucket. Substituting again with non-fat Greek yogurt, or avocado (which is full of “good” fats), can make this a bit better. That said, when paired with the other BBQ items, a green salad might be a better choice.
Linda Sartor, a certified diabetes educator, clinical dietitian, and diabetes nutritionist in Penn’s Rodebaugh Diabetes Center, said what might actually be best is to “opt for only half of an ear of corn, or to choose just one starch side (either potato/pasta salad or baked beans) instead of eating all of them. Being selective with these items will help manage blood sugars.”
Providing these kinds of alternatives is one way Sartor and her team help patients with diabetes in the clinic navigate cooking and meal planning. Patients newly diagnosed with diabetes participate in nutrition workshops—often led by Sartor—where they learn about foods they should avoid, swaps they can make for indulgent dishes, and new food groups to focus on to manage their disease. Some patients may even reverse their diabetes by making changes to their diet, like cutting out grains, carbs, sweets, meat, dairy, and night eating.
Hot dogs and hamburgers
These items are often the main event—and perhaps those with the most potential for negative impacts.
“Grilling or barbecuing meats creates advanced glycation end products (AEGs) like nitrosamines, that have been linked to increased risks of cancer, specifically colorectal and pancreatic,” says Sartor, a fact that made headlines following the WHO report on this connection and new USDA dietary guidelines that stressed moderation when consuming not only processed meats, but all processed foods.
While these foods don’t need to be stricken entirely from the diet, they should be eaten sparingly, and perhaps not all in one sitting, says Daniel Rader, chair of the department of Genetics and chief of the division of Translational Medicine and Human Genetics.
On top of these carcinogens, Sartor adds, “processed meats like hot dogs, hamburgers, wings, and ribs contain lots of artery-clogging fats and salt, which can raise blood pressure and cholesterol levels in the body.” Instead of loading up on red or processed meat, Sartor suggests making baked chicken breast (without the skin) with homemade BBQ sauce, or opting for boneless BBQ chicken “wings” from chicken tenders, and baking them in the oven instead of grilling.
One key tip Sartor offers for managing many BBQ staples is to try homemade sauces. Duffy echoed this in the Men’s Health article, noting that many meat rubs “are loaded with salt, sugar, and preservatives,” which the experts seem to agree can negatively impact health.
“The average hot dog and hamburger come in at around 300 calories with a bun, but the real challenge comes with the toppings,” Tewksbury says. “Most people load up their burgers or dogs with cheese, ketchup, mayo, and other high-calorie, high-fat items. If you do decide to have one of these and opt for a condiment, stick with low-calorie ones like mustard and add veggies like lettuce, tomato, onion, or pickles.”
Duffy agrees, telling Men’s Health that “mustard is also a great sugar-free option—assuming you don’t opt for honey mustard, which tends to include lots of sugar.” Ultimately, consuming BBQ fare sparingly is key, as is opting for homemade sauces and condiments, making selective choices, and substituting high-fat ingredients for low-cal options. Taken together, this advice can take some of the health risks—and the guilt—out of these summer foods.
Bottlenose dolphins provide extended maternal care, which might play a role in the evolution of menopause (Photo credit: Flickr Creative Commons/BrandonTrentler)
By Jacob Williamson-Rea
Our weekly round-up compiles stories and news, both from here at Penn and around the world, that highlight the intersection of animal, environmental, and human health.
Dolphins could unveil the origins of menopause
Science, July 17, 2018
Humans and three kinds of whales are the only species that experience menopause. Information about the origin of this biological process, however, might come from an unlikely source: the bottlenose dolphin, which doesn’t experience it but does provide extended maternal care.
Is what’s good for the lemurs also good for the locals?
NPR, July 11, 2018
As Madagascar’s population expands, so does the country’s need for farming land. But because several endangered species live in the forests there, the government limited clearing and logging, which led to new solutions—and new problems.
Killing rats could save coral reefs
BBC, July 12, 2018
Bird droppings directly benefit natural reefs, but tropical areas inhabited by invasive rats are seeing plummeting seabird populations, according to a new study published in Nature.
They’re out in the woods picking up ticks—on purpose
The Washington Post, July 15, 2018
Researchers and scientists have teamed up in Minnesota to collect ticks, hoping to identify both current and future threats posed to humans.
Late snowpack signals a lost summer for Greenland’s shorebirds
Scientific American, July 13, 2018
Greenland’s shorebirds rely on a brief window of Arctic summer, but that window began too late this year. Some climate models show such a phenomenon becoming common, which, according to experts, could alter bird populations.
Ten species of shark coming to the UK as waters warm
The Guardian, July 18, 2018
Climate change leads to shifting temperatures and subsequent changes in animal demographics. As seas around the United Kingdom get warmer, they’ll become home to several new shark species.
Lyme disease, West Nile virus, Zika, chikungunya, and dengue are among the vector-borne infections making headlines. Penn researchers shed light on what’s behind the spread and how to stay safe.
Sara Cherry has a visceral memory of when Asian tiger mosquitoes, Aedes albopictus, first found their way into the Philadelphia region.
“I used to like to eat outside with my lab when I first started working here at Penn,” she says. “But then the tigers came and started terrorizing us and we had to eat inside. They are aggressive, and their bites cause welts.”
Sara Cherry of Penn Medicine studies viruses transmitted by mosquitoes. (Photo by Eric Sucar)
Vectors of viral diseases including yellow fever, Zika, dengue, and chikungunya, A. albopictus and its close relative Aedes aegpytii have undergone a dramatic global expansion in recent years, and now dwell contentedly in the yards and outdoor spaces frequented by hundreds of millions of Americans.
To Cherry, a professor in Penn’s Perelman School of Medicine who studies viruses transmitted by mosquitoes, the tiger mosquitoes are emblematic of the changes afoot when it comes to vector-borne disease, changes wrought in many cases by climate change and globalization.
According to the U.S. Centers for Disease Control and Prevention, diseases transmitted by mosquitoes and ticks represent a growing public health problem. From 2004 to 2016, the agency found that insect-borne diseases more than tripled, with nine new-to-the-U.S. diseases emerging in that period. Meanwhile, in the past several months, an introduced tick species has been reported in the eastern U.S., raising concerns about how this new player in the landscape could influence disease risks.
With potential dangers lurking within the bodies of tiny insects, the question may surface: Is it safe to venture outside anymore? Penn researchers, keeping tabs on the news and making headway in the lab, offer a clear-eyed—though not cut-and-dry—view of the state of vector-borne disease. The threats may be real, they note, but the precautions are generally straightforward.
Risks, old and new
James Lok of Penn’s School of Veterinary Medicine specializes in parasite biology, but also teaches students about the ins and outs of a wide variety of zoonotic diseases transmitted by insects. He sees a connection between global travel and global commerce and the new threats posed to the continental U.S. by exotic diseases once only associated with tropical areas, such as Zika and chikungunya virus.
“The global economy and globalization generally have been social trends that have fostered a lot of these diseases,” Lok says. “There are a lot of ways that a tick like the exotic one found in New Jersey can hitch a ride on livestock and get over here, then when they’re in, they’re in.”
The introduced tick, Haemaphysalis longicornis, with a common name of longhorned or bush tick, was found on a sheep in 2017 and seems to have overwintered in New Jersey. This spring, reports cropped up in Virginia, West Virginia, and Arkansas as well.
“This tick is known to be an aggressive invader,” says Dustin Brisson, a biologist in the School of Arts and Sciences who studies the ecological and evolutionary trends of the bacteria that causes Lyme disease and of Ixodes scapularis, the black-legged tick that carries it. H. longicornis is already known to spread viral diseases in its native East Asia.
Brisson says that with a new vector like this, researchers generally have two sets of questions. “The more immediate ones relate to its vector competence,” he says. “Can it transmit diseases that we already have here in North America? Where are the risks?”
James Lok of Penn Vet specializes in parasite biology. (Photo by Eric Sucar)
Equally important but less urgent, he says, are a second set of questions relating to the tick’s ecology. “Does it displace other organisms, like Ixodes scapularis? What effect does it have on animal communities? What kind of densities does it live at? These are questions that can play back into public health,” Brisson says.
Meanwhile, our native black-legged ticks have been busy, transmitting Lyme disease in ever-increasing numbers, accounting for more than 80 percent of tick-borne diseases. Other, more dangerous infections, such as Powassan virus and anaplasmosis, are also transmitted by these ticks. Brisson’s research has examined what types of landscapes are most likely to harbor ticks, and the role of certain host species in the transmission of different strains of the Lyme bacteria. Pulling together this information into large-scale models of the environmental features that influence disease risk in humans could inform long-term disease management strategies, he says.
Scientists lump together a host of pathogens into the category known as “emerging infectious diseases.” Oftentimes, however, these infections aren’t brand new, they’re just new to the developed world, according to Cherry.
“It may be an unpopular view, but we have very little understanding of these diseases because historically they’ve mainly affected developing nations,” she says.
Yet that geographic disparity is breaking down of late. One need look no further than the outbreak of Zika in 2015 to 2017 to see how a virus once primarily confined to Brazil impacted the continental U.S. And while that outbreak is past, other infections, such as dengue and chikungunya, circulate in the Caribbean and are believed to pose a threat to the U.S., especially now that their vectors, certain Aedes mosquitoes, have become well-established here.
Cherry’s lab studies these viruses and many others, seeking commonalities in how these pathogens infect both mosquitoes and humans. The goal is to find potential drug targets to shut down viral spread—ideally targets that could work to treat more than one disease.
Despite her focus on viruses, Cherry believes that, currently, the best strategy for combatting these types of diseases is targeting the vectors, not the pathogens.
“When there was an outbreak of yellow fever in the 1700s in Philadelphia, what did we do? We killed the mosquitoes,” she says. “What is the best tool we have against malaria in Africa? Bed nets. When you step back, we don’t know a lot about how to deal with these diseases, but we do know how to kill and manage insects.”
Michael Povelones is one researcher investigating ever-more sophisticated ways of manipulating mosquitoes to benefit human health. In a high-tech insectary in the School of Veterinary Medicine, Povelones’s lab rears and infects mosquitoes with a variety of pathogens, then studies how the insects’ own immune systems do battle with the invaders. The insects’ ability to either vanquish or succumb to infection with, for example, malaria, has implications for whether they’ll be able to pass the parasite onto humans.
Michael Povelones of the Vet School, is investigating ever-more sophisticated ways to manipulate mosquitoes to benefit human health. (Photo by Eric Sucar)
A long-term possibility stemming from Povelones’s work would be to manipulate the mosquito immune system in such a way that the insect would no longer be able to transmit disease. While we may be far off from the widespread release of genetically modified mosquitoes, California has already seen the release of millions of mosquitoes infected with Wolbachia, a genus of bacteria that renders mosquitoes sterile, orchestrated by Google’s sister company, Verily. Kaycie Hopkins, a Penn grad who completed her Ph.D. working in Cherry’s lab, is one of the biologists collaborating with software engineers and automation experts on these projects at Verily.
“I’m heartened by the fact that there are companies and organizations working on these large-scale efforts,” Povelones says.
Mosquito-transmitted diseases are not only a problem for humans; they infect wild and domestic animals as well. In a project taken up during the past couple of years, Povelones and members of his lab have been investigating what makes certain mosquito species resistant to heartworm, and others susceptible. While medications already on the market effectively keep pets free of heartworm, Povelones says isolated reports of drug-resistant heartworm give reason to look for other strategies to go after the parasite, in addition to the swells of infections that arise among feral and shelter animal populations, especially during hurricane season in the South.
While the news about scary-sounding diseases like chikungunya or anaplasmosis can feel overwhelming, the researchers underscore that simple precautions can make a big dent in the risk of acquiring a vector-borne infection:
- Use high-potency DEET insect repellants. They remain the gold-standard for avoiding both tick and mosquito bites. Other repellants, such as permethrin, are effective at keeping away ticks when applied to clothing.
- Wear long pants and long sleeves as well as insect repellant when venturing into tick habitat—think of landscapes where forests meet shorter vegetation, like wooded paths lined by taller grasses. Then do a thorough body check for ticks upon returning home. “An entomologist I spoke with said that taking these kinds of tick precautions should be as engrained a behavior as fastening your seat belt in the car,” Lok says.
- Eliminate standing water that can provide mosquito breeding habitats near home environments. A. aegypti and A. albopictus larvae can thrive in an upturned bottle cap. “There’s no point in hiring a firm to spread insecticide over your property if you’re not going to dump out the water collecting in your planters, or if you’re leaving your dog’s water dish out for days at a time,” Cherry says.
- Keep pets up to date on vaccinations and use FDA-approved medications or collars to prevent diseases such as heartworm and deter fleas, ticks, and mosquitoes.
- Consult a physician about any needed vaccinations or preventive therapies when traveling to countries where vector-borne diseases may be prevalent.
In other words, continue to enjoy outdoor activities, keeping in mind that there is reason to be cautious.
“I don’t think people should panic,” Cherry says, “but I do think they should learn the world is getting small. You can’t just put your head down and think that only people in other countries get these diseases; we’re all the same place now—it’s one place now.”
Dustin Brisson is an associate professor of biology in the School of Arts and Sciences.
Sara Cherry is a professor of microbiology in the Perelman School of Medicine.
James Lok is a professor of parasitology in the School of Veterinary Medicine.
Michael Povelones is an assistant professor of pathobiology in the School of Veterinary Medicine.