Lab Culture Ep. 8: Leaders for a TB free world

Every year on March 24, APHL recognizes World TB Day, a day to focus on the valuable work of our members and partners. While tuberculosis is often considered a disease of the past, it is resurging and presenting significant new public health challenges including drug resistance. This World TB Day, we are sharing an insightful conversation between two TB laboratory leaders: Dr. Marie-Claire Rowlinson, assistant laboratory director, Bureau of Public Health Laboratories, Florida Department of Health and Dr. Beverly Metchock, team lead, TB Reference Laboratory, CDC Division of Tuberculosis Elimination.

You can listen to our show via the player embedded below or on iTunes, Stitcher or wherever you get your podcasts. Please be sure to subscribe to Lab Culture so you never miss an episode.

Below you will find a complete transcript of this conversation as well as links to more information on TB.

Recorded March 16, 2018

Marie-Claire Rowlinson: Hi, Bev. Good to talk to you today.

Beverly “Bev” Metchock: Hi, how are you?

Marie-Claire: I’m good. So looking forward to having a conversation today. Couple of questions about TB and how you ended up being interested in TB. So maybe I can start and ask you: As a kid, how did you find yourself interested in science? Were you curious about the world around you? Did you always know that you wanted to work in a science related career?

World TB DayBev: Well, that’s an interesting question, and really not that I can remember. I was a good student overall, and I did enjoy biology and chemistry in high school. I certainly didn’t enjoy physics! And when it came time to choose a college major I was very pragmatic. I chose medical technology because I knew I could get a job. So I kind of went into the field very uninformed as to what it would be. But then when I took my first medical micro course as a junior in college, I just fell in love with clinical micro and I knew that’s where I wanted to go. And I was fortunate in my med tech rotation in a tertiary care medical center, micro was the first lab that I rotated through before chemistry and hematology and blood bank. And so I was able to start working in the micro lab on evenings and weekends, and I was offered a position – a full time position – when I graduated so I was very fortunate to find what I wanted to do, to sort of just fall into it. How about you?

Marie-Claire: Kind of similar. I mean, I think I was as a kid was always interested in biology and space and medicine and those kinds of things. But actually it wasn’t until high school that my biology teacher, when I was looking at degree courses to take, told me that she thought I would be a great microbiologist. And I don’t know if she knows what a profound impact that she’d go on to have in my life. I think it also happened to coincide with the film, Outbreak. I don’t know if you remember that. I think I really wanted to be a disease detective, but, sort of like you say, I don’t think I really knew exactly what I was doing when I got into medical microbiology. But I think I always dreamt of having a career in science, and I still have some parts of that dream yet to realize. I think it’s an exciting field to be in.

Marie-Claire: Can you think of a person or an event that inspired or encouraged you to get involved with public health laboratories or TB testing specifically?

Bev: Well, when I was working in the hospital as a medical technologist in the micro laboratory, I actually became interested in hospital acquired infections and antibiotic resistance. Personally what happened is my father had a hospital acquired – post-surgical infection – at the actual hospital where I worked. And then I was fortunate to be able to work – at a different situation – but work with the infection control practitioners and be the microbiologist that was involved in an outbreak of aminoglycoside-resistant Enterobacteriaceae in the neonatal intensive care unit. So I got very interested in hospital acquired infections, hospital epidemiology and antibiotic resistance. And, to be quite honest, I was one of the people who thought people don’t get TB anymore in the United States. So my original career path when I finally did go back to continue my education was in a school of public health because I wanted to get a background in epidemiology and statistics, and I thought that was the path I was going to go. But then when I got my job at Grady Memorial Hospital in Atlanta I had to become an “expert in TB” out of necessity because there was a lot of TB in Atlanta and since then there’s been no going back. I’ve been in and been involved in TB diagnostics since. How about you?

Marie-Claire: Well, I think that’s so fascinating that you say that because I, sort of in a way, have a similar story. So my Ph.D. is in parasitology, so not related to TB at all, but I did do quite a lot of international work when I was doing my Ph.D. I guess I was kind of always interested in tropical medicine or at least diseases that disproportionately affected disadvantaged populations and people who maybe didn’t have access to adequate healthcare including lab testing. But similarly like you, growing up in the UK, TB felt like a disease of the past or from another country. As you said, I think we all know that that’s not the case. And, in fact, in the UK there’s been a real resurgence of the disease in recent years. And when I was thinking about this podcast, doing some research, I saw that there were 10.5 cases per 100,000 population in 2015 (this is in the UK), but this was down from 15.6 per 100,000 in 2011 compared to three cases per 100,000 in the US in 2015. So, I mean, at that time when I was in the UK, I didn’t really think about TB, but now that I know so much about it and realize that it really is a great challenge in clinical diagnostics and in public health.

Bev: Similarly when I was at Grady that was a time when TB was “resurging” in the United States. And so there was a lot of pressure in the micro laboratory to do quicker diagnosis, to implement the newer technology that was available. And I remember in a matter of a few years when we went from just doing culture on solid media to transitioning to the radiometric broth method to incorporation of DNA probes for identification and then nucleic acid amplification for direct specimen testing. And I recall the days when… I remember one particular situation where a physician called and said, “This can’t this can’t be right.” And I said, “What do you mean?” He said, “We only sent the cultures down three days ago and you’re telling us it’s TB.” So the transition from taking weeks to months to just a few days – to be so very involved in that transitioning in such a short period of time and thinking about how long we have been doing things the same way and then all of a sudden there’s like this revolution. It’s a very exciting field to be in.

Marie-Claire: Absolutely. Can you think of any people or mentors who particularly inspired you? I have a couple to mention, for sure.

Bev: Well, like I said, at Grady the medical director of the micro lab, Dr. John McGowan, and then the supervisors in the laboratory, Portia Williams and David Lonsway, they taught me a lot and we’re all very involved together with working out how we were going to handle the situation in the medical center and working with the folks in the Georgia Public Health Laboratory to coordinate testing. Obviously, it was before I was at CDC, but working with the people here at CDC to coordinate testing that was being done here at CDC so we can get results as rapidly as possible. There’s a lot of people that were involved, and one I particularly remember as well was a hospital epidemiologist at the time, Hank Blumberg, who was a very young enthusiastic person who we worked really closely with his team in infection control and hospital epidemiology. How about your folks?

Marie-Claire: Well, I was quite lucky. When I came to the US to do my post-doctoral fellowship at UCLA, I sort of knew that I wanted to go into public health and actually Dr. Ed Desmond really encouraged me whilst I was doing my postdoc to go into public health and mentored me at the California state lab for two weeks. He arranged for me to go for a visit there for two weeks and spend that time with him. And I’m sure as the listeners out there know, Ed Desmond is a pretty renowned TB lab expert, so I was lucky to have him as one of my first mentors and he’s still a mentor to me and we still get to work together quite often. So that’s exciting. And then I suppose… I actually worked at APHL after I did my postdoc and I was in the global health program. So I was doing quite…although it was mostly focused on HIV there was still a big TB component so that was also a big driver for me in terms of public health labs and TB. But when I left APHL and joined Florida Department of Health, I was actually hired by Dr. Max Salfinger, who, again, people may be very familiar with his name, he’s a pretty renowned TB expert as well and has been an incredible mentor to me. And even though he actually moved to National Jewish Health shortly after I joined the Florida Department of Health we still – so this is six years later – we still have bi-weekly TB calls. So that’s made a big impression on me and been a big reason why TB has been a big part of my work. I think I would lastly mention also that the lab here in Florida really is a state of the art lab, always pushing the envelope, being involved in studies, and I think having such a strong lab in Florida and also having such a great collaborative relationship with our TB control program has been instrumental in my work in TB and my interest in TB. And I particularly I love working with Dr. David Ashkin, he’s our TB medical director for the Florida Department of Health, and he’s really inspiring and really dedicated. And actually, he does an amazing job of engaging the lab in the work that the TB control program does. So we really get to hear about the clinical side of TB care and the importance that the lab results have on patient care because sometimes we’re in the lab and we never actually hear about patients, but he really involved us in that and all the other facets of TB control and I find that really fascinating.

Bev: Yeah, I think that’s one of the most enjoyable parts of my job – is interacting with our public health laboratory partners, but state and local TB control practitioners, the TB clinicians… And TB laboratory work, I mean we are so important in the whole team of taking care of a patient and I think in some respects that’s unique in the clinical micro world that we are involved so much in laboratory results. And I think that the clinicians that we deal with understand that and treat us as part of the diagnostic team. So that’s the part I really enjoy of my position here. Being part of a team.

Marie-Claire: Yeah. And that’s the same feeling we have here and even the bench – I know the bench techs really feel a part of that team as well like everybody is involved in that process. So it’s really good.

Marie-Claire: Do you remember what first drew you into TB? Or was it really just being at Grady and being in Atlanta and seeing the resurgence of TB and TB cases?

Bev: I was drawn in out of necessity – to be able to do what needed to be done. But it was an interesting time because technology was changing, we were dealing with a lot of cases and trying to implement new testing, new technology in the laboratory. Like I said earlier, I would have never thought I would end up working with TB, but once I started it was really something I really enjoyed and being involved in that.

Marie-Claire: Yeah, I think once you start working on TB you realize how interesting it is. I think I love it because it’s so interesting for so many reasons. I mean, you think about it being such an ancient disease that you think about history, music, art, literature, I mean it’s steeped in TB references. So I can go back to books that I read when I was younger and be like, “Oh, there was a TB reference in there!” or  “That composer died of TB” or “He was writing this piece of music or painting this painting when he was afflicted with the disease.” So I think for me that’s really interesting. And then from another standpoint the fact that people can be exposed to TB but never develop symptoms or maybe only become symptomatic under certain situations later on. That makes it difficult to diagnose. And now with multidrug resistant TB and extensively drug resistant TB and things like coinfection with HIV, it’s driving more disease and driving morbidity with disease making, I think, accurate and timely diagnosis even more important. So I think all of those challenges for me make it really interesting, and so with this goal of TB Elimination I feel that we’ve got our work cut out for us.

Bev: Yes we do.

Marie-Claire: And I suppose I have to say again, for me being drawn into TB and why I’ve stayed interested in this field as well is that working in that team with these really dedicated people every day – the TB nurses and so forth in all the counties – are just so dedicated.

Bev: Yeah and that’s the thing. You know, if you don’t get outside the lab, you don’t realize that. But the dedication of all the folks who work with patients who have TB. And I think that’s why I enjoy when we have the National TB Controllers conference in the National Laboratory meeting that all those folks get together. It’s such a strong… it’s such a good feeling and a good meeting, and you meet your peers and people you talk to on the phone you meet them in person and everybody’s working on the same team. It is a really rewarding opportunity that I have here to have this job.

Marie-Claire: Absolutely. Can you… Thinking of that kind of thing, can you think of a specific case or situation where you really felt the impact of your work? Or your lab, the impact for you or your lab… the impact that your lab had on a community or a patient. I guess being at CDC even more broadly you have a national impact on TB lab diagnostics.

Bev: Yeah, I don’t want to really mention any specific cases. There are certain cases I can recall from my days at Grady and in certain cases that we’ve been involved with here with laboratory testing at CDC. But I think… we feel that the group here in the reference laboratory, I think we feel the impact all the time. We get phone calls from physicians, phone calls from TB control programs, obviously from the laboratory asking about testing. And once we implemented our molecular detection of drug resistance testing service I think we demonstrated that referral of specimens or isolates worked within the United States and we can get results out in relatively good real time that really impact decision making around particular patients. So whether it’s… somebody is a caregiver in a nursery and we can say fairly reliably it’s not drug resistant TB within a day or two versus letting them know “yes, indeed you have a case that’s drug resistant TB” and we know it’s going to be resistant to these other drugs, that the physicians can make good decisions about how they’re going to treat that patient. And I think how we impacted that kind of decision making. When we started the testing service – when before we started and we were talking to experts about “this is what we’re going to do,” one of the questions I was asked was, “Well, how many specimens do you think you’re going to get?” And I honestly didn’t know. I didn’t know if folks were going to use the service, if they’re going to trust the results or are still going to do the rapid molecular testing and still wait for the traditional growth based drug susceptibility testing. And that has – I think it’s a little bit changed over time – but I think now that’s one of the first things that folks go to and I know for you in Florida, you do the Hain tests and it’s the same. It’s the same type of thing that they get immediate information that either I would think either makes them feel relieved or knowing that now I can make a decision about what I’m going to do next with this patient based on the rapid tests that the laboratories can do.

Marie-Claire: Yeah. Even if it’s just to hold medications while waiting for something right. I think that for turnaround time makes a huge difference. I know you know, but we use the MDDR service a lot and it’s really amazing. And our physicians and providers that are big users of the MDDR really rely heavily on the information that comes from that. It’s a really wonderful service.

Bev: I appreciate that.

Marie-Claire: Yeah, I mean, for us, I feel that being in a state, we sometimes have these cases in situations where we can really feel the impact of our work. And as I’ve said before really being involved as a team with our TB control program. If I think at a community level… the Jacksonville Bureau of Public Health Labs is in the county, Duval County, and we actually had quite a serious TB outbreak. I don’t know if you remember back in 2012.

Bev: Right.

Marie-Claire: It infected the homeless population in Duval County, and so over the last six years the county has really made great strides in this patient population. And one of the ways that the lab has been involved in this effort is, in fact the last two years, our lab has been doing IGRA testing for their shelter card program. The shelter card program is the system to routinely perform testing and assessment for symptoms of TB for Duval County’s homeless clients that are seeking admittance to area shelters. So this has had an important impact on preventing transmission of TB amongst the homeless population, and so for the lab to be a part of that effort has been has been really interesting and really great, and having the opportunity to implement IGRA at our lab and see it have an impact has been really interesting. And then if I think about specific cases, as you said, there are several cases that come along every year that are really interesting, but I always have one that comes to mind because we had a really complicated patient a few years ago that – despite having no risk factors – he had disseminated TB. In the lab we were able to confirm diagnosis. We were able to confirm that it was disseminated TB by confirmation of TB from several body sites including CNS involvement and it actually turned out that strain had an rpoB mutation which was associated with low level resistance to rifampin. And so the TB control program actually ended up treating this case as MDR TB and I think over the course of time the lab received 20-plus specimens on this patient. And so, about a year and a half after that, it was actually amazing, we got to meet that person.

Bev: Oh, wow!

Marie-Claire: Yeah, and hear his survivor’s story. You know, sometimes we actually do get to meet the patients. And that was that was really inspiring for me. And he was successfully treated.

Bev: Well that’s great. So that’s an advantage of you being at the state… that you are closer to the patients than… we’re another step removed from them. So yes, I’ve not had that opportunity. But yeah that sounds like a…

Marie-Claire: Even hearing the survivor stories at the NTCA conferences, I think as you said, makes the job really rewarding because you see that all of the efforts of the lab, of the program, treating physicians and clinicians, everybody that’s a part of that team and helping these patients. So when you actually get to hear the survivors on the stage it’s pretty amazing it’s pretty powerful.

Bev: I absolutely agree. To hear the stories and what they have to go through with taking drugs that have side effects or the stigma of having TB and all those things. It really is. If you didn’t understand. You know, sometimes we have folks in the lab who are doing research or visitors and they don’t really understand the full effects, and that when they hear those stories they really understand it, and it’s inspiring what these patients who have TB go through and it’s great that they’re willing to share their stories.

Marie-Claire: I agree. Well thank you, Bev, it was really great talking to you today!

Bev: Well, thank you, Marie-Claire! I really appreciate the chance to have this conversation.

Marie-Claire: We’ll keep working towards a TB free world.

Bev: We can only hope.

 

The post Lab Culture Ep. 8: Leaders for a TB free world appeared first on APHL Lab Blog.

Hurricane preparation and response resource list

Hurricane preparation and response resource list | www.APHLblog.org

Updated September 15, 2017

In the wake of hurricanes Harvey and Irma, public health laboratories in affected regions will be busy testing for potential environmental contamination, monitoring for increased water- and mosquito-borne diseases, or repairing damage to their own facilities. APHL has activated its Incident Command System (ICS) to support member laboratories with their response. The ICS team is participating in CDC’s Emergency Operations Center (EOC) State/Local and Partner Conference Calls, and will assist member labs with their response, facilitate communications between CDC and member labs, and share lab needs/stories with policy makers and the public.

Below are helpful resources for those communities hit by the recent storms. Many of these resources are useful for any severe weather event, not just Hurricanes Harvey and Irma.

Preparing for and weathering the storm

Hurricanes, Preparation and Response, EPA
Hurricane Preparedness Checklist, FDA
Preparing for a Hurricane or Tropical Storm, CDC
Flooding Toolkit, National Public Health Information Coalition
Disaster Assistance.gov, US government platform for locating disaster-related resources
Federal Emergency Management Agency (FEMA) Toll-free FEMA hotline for survivors of Hurricane Harvey: 1-800-621-FEMA

Keeping your family and community healthy after the storm

Food Safety:
Food Safety Tips for Areas Affected by Hurricane Irma, USDA press release
Protect Food and Water Before, During and After a Storm, FDA

Infectious Diseases:
Emerging and Zoonotic Infectious Diseases, CDC
Vector-borne Diseases, CDC​​​​​​​
Waterborne Disease Prevention, CDC

Drinking Water:
Drinking Water Safety and Testing Information for Texas, Texas Commission on Environmental Quality (accredited labs for microbial testing of drinking water, advice for customers of public water systems, disinfecting your well, etc.)
Drinking Water Testing and Information for Houston, TX, City of Houston
Private Wells: What to Do after the Flood, EPA
Private Wells: Water-related Diseases and Contaminants, CDC
Health Department Laboratory, Drinking Water Testing and Information, City of Houston

Other:
Carbon Monoxide Poisoning – Clinical Guidance, CDC
Mold: Cleanup and Remediation, CDC
Mold: Flood Cleanup, EPA
Waste Management, EPA

Rebuilding and repair

Cleanup after a Hurricane, CDC
Status of Systems in Areas Affected by Harvey, Texas Commission on Environmental Quality – drinking water, waste water and sewage, residential wells, flood waters, water infrastructure

The post Hurricane preparation and response resource list appeared first on APHL Lab Blog.

Century of Florida hurricanes

Florida hurricanes

Florida has seen a lot of hurricanes come and go. Lazaro Gamio for the Washington Post looks at all the hurricanes that made their way towards the state over the past 100 years.

The thought of a hurricane freaks me out. This must be how non-Californians feel about earthquakes.

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A chorus line high kicks during a show at Cafe Le Can Can in…



A chorus line high kicks during a show at Cafe Le Can Can in Miami Beach, Florida, 1963. Photograph by Dean Conger, National Geographic Creative

Shell hunters in sunglasses examine a lion’s paw, a prized…



Shell hunters in sunglasses examine a lion’s paw, a prized find on Sanibel Island in Florida, 1959. Photograph by Paul Zahl, National Geographic Creative

Highlights from the 2015 Meeting of the Vision Sciences Society

Going to conferences is one of my favorite aspects about being a scientist. As a PhD student, I spend a lot of my life in solitude: when I read new literature, when I program new experiments, or when I conduct … Continue reading »

The post Highlights from the 2015 Meeting of the Vision Sciences Society appeared first on PLOS Blogs Network.

Arsenic in the water: Are filters and bottled water enough protection?

By Melissa Murray Jordan, senior environmental epidemiologist, Bureau of Epidemiology, Division of Disease Control and Health Protection, Florida Department of Health

Arsenic in the water: Are filters and bottled water enough protection? | www.aphlblog.org

Private wells in many central Florida counties have been found to contain levels of arsenic above the federal maximum containment level (MCL) of 10 μg/L (micrograms per liter). Knowing it is present is important to the public’s health; but how serious is this? Even exposure to low amounts of arsenic can potentially lead to an abnormal heart rhythm, damage to blood vessels, and a tingling sensation in hands and feet. Inorganic arsenic, the type in this water, is a carcinogen when consumed over many years. High levels of exposure to arsenic may lead to death. To address this known contamination, the Florida Safe Water Restoration Program provided filters or bottled water to households with arsenic levels in private wells between 10 μg/L and 50 μg/L. In partnership with the Florida Department of Environmental Protection, the Florida Department of Health (FDOH) decided to test the effectiveness of this program as well as explore any further impact of the contaminated water on residents living in areas of concern.

The study targeted Hernando County where nearly 400 of the 1,200 wells tested had elevated arsenic levels. This time, scientists wanted to understand if residents who weren’t drinking unfiltered well water (people who were drinking bottled water or using a filter in their homes) were still ingesting unsafe levels of arsenic through other unfiltered tap water in the home. It is widely known that arsenic exposure often occurs from drinking water, but what about exposure to water in other ways? What about brushing your teeth with unfiltered water? Or when cooking with unfiltered water?

A critical initial step of this project was forming a workgroup with representatives from many disciplines to inform various steps of the study:

  • Environmental specialists to provide background information on areas of known arsenic contamination in the state and details on the private well testing database;
  • Epidemiologists to provide guidance on the study design and sample size;
  • Laboratorians for developing the protocol for collecting, shipping and testing the water and urine samples;
  • Toxicologists to interpret the risk of arsenic exposure;
  • And communications experts to develop press releases, frequently asked questions and coordinate media.

Funding from CDC’s Environmental Public Health Tracking program allowed the state to engage these experts and ensured a high-quality study.

From April through July of 2013, 360 individuals from 166 households participated in the study. Nearly 50% of the participants were from control households: households with well water arsenic levels below 8 μg/L (below MCL). The other half were classified as case households: households with arsenic levels exceeding 10 μg/L (at or above the MCL). Participants provided urine and water samples, and completed a questionnaire on water consumption, dietary history and other possible sources of arsenic exposures. Water and urine samples were sent to the public health laboratory in Jacksonville, Florida for analysis of total arsenic.

The majority of case households (59.8%) reported bottled water as their most common source of drinking water, and 47.5% reported using bottled water for cooking. However, the majority of case households reported using unfiltered well water to brush their teeth (88.7%).

In many biomonitoring studies, only adults participate. This study also included children. Simply because of their size, a small amount of a chemical can have a larger impact in a child than the same amount in an adult. Scientists felt it was valuable to look at a range of people without omitting the smallest members of the community. Additionally, children tend to have different behaviors from the adults in their homes. For example, they may take baths rather than showers – and kids may be more likely to ingest that bath water. Fortunately, no children in this study were found to have elevated levels of inorganic arsenic.

Results: Residents using filtered or bottled water for drinking were not at an increased risk for arsenic exposure through other unfiltered household water sources.

The distribution of filters and bottled water was helping to prevent residents from exposure to arsenic. While testing for contaminants in the wells was an important first step to understanding the problem, biomonitoring provided a more complete picture of the full impact on a population. This was obviously good news to the residents and researchers alike.

The National Geographic Found Tumblr is now Webby award-winning!…





The National Geographic Found Tumblr is now Webby award-winning! We recieved the People’s Voice award for Best Use of Photography.

Operators man computers at Eastern Airlines’ reservations center in Miami, November 1970.Photograph by Bruce Dale, National Geographic Creative

Coming (Back) to America? What 2013 Can Teach Us About Dengue in the United States

jumbled picture of words related to dengue feverBy Tyler Sharp

2013 was a banner year for dengue in the United States: an outbreak with 22 associated cases was identified in Florida; another outbreak was detected in south Texas along the U.S./Mexico border;  Aedes aegypti, the most efficient mosquito vector of dengue, was detected in central-California; a locally acquired dengue case was detected outside of NYC; and Puerto Rico experienced a sizeable dengue epidemic that had been ongoing  since late 2012.  So, what’s next?  Is this par for the course, or was 2013 an anomaly?  In this blog, I’ll discuss the history of dengue in the U.S., what the future might hold, and what you can do to reduce your risk of getting infected while at home or abroad.

History of Dengue in the U.S.

world map of dengue infectionsDengue is a tropical illness that causes fever, body pain, severe headache and eye pain, and sometimes minor bleeding from the nose or gums.  Four different but related viruses can cause dengue, all of which are transmitted by mosquitoes of the Aedes genus.  Because immunity against one virus does not protect you from infection with the other three, you can get dengue up to four times in your life. Around 5% of dengue cases progress to severe dengue, which can result in severe bleeding, shock, and even death.  Although most Americans have never heard of dengue because there is not much of it in the continental United States, dengue is actually quite common throughout the tropics, where 400 million infections occurred in 2010.

Despite relatively low case counts in recent decades, dengue is no stranger to the United States.  Dr. Benjamin Rush, a signatory of the Declaration of Independence, documented a dengue outbreak in Philadelphia in 1780.  Ships arriving from foreign ports were bringing mosquitoes and infected people back to port cities in the U.S., where local outbreaks then followed.  This continued along the eastern seaboard and Gulf coast for the next 150+ years: an outbreak in 1873 affected an estimated 40,000 residents of New Orleans, and another in 1922 made its way through the entire Gulf coast.  The last recorded dengue outbreak in the continental U.S. occurred in 1945 when a soldier returning from Guyana to Louisiana brought the virus home with him, resulting in an outbreak in which 145 people were affected.

Aedes Eradication Campaign

black and white image of DDT being sprayedSo why were no dengue outbreaks identified in the U.S. between 1945 and now?  Most prominently, the chemical DDT was used beginning in the 1940s to nearly eliminate Aedes mosquitoes, which also transmit yellow fever and chikungunya, from the Americas.  However, before the mission was completed, the detrimental effect of DDT on the environment was made public and elimination efforts were halted.  Consequently, over the next several decades mosquito populations gradually re-established themselves in the U.S. and abroad.  As the burden of dengue in the tropics began to increase in the 1980s and 1990s and Americans began to travel internationally more frequently, more and more travelers began to return to the U.S. with the unwanted souvenir of dengue.

Present-day dengue in the U.S.

Following a large dengue epidemic in Mexico that spilled over into south Texas in 2005, an investigation revealed not only that stable populations of Aedes mosquitoes were established along the Texas side of the U.S.-Mexico border, but also that 39% of residents had been previously infected with a dengue virus.  Because several of these individuals had never left the United States, this demonstrated that dengue virus had been circulating in south Texas.

On the other side of the Gulf of Mexico, in 2009 a dengue outbreak was detected in Key West, Florida, which was likely caused by importation of the virus in a traveler returning from Central America.  The outbreak ultimately resulted in 5% of the small island community being infected.  Dengue cases resulting from infection in Florida continued to be detected in the area in 2010 and 2011, and one report suggested that the virus may have become established in the region.  Thankfully, no additional locally-acquired cases were reported in Key West in 2012, although dengue did pop up in Florida again in 2013. These outbreaks have made it clear that although rare, conditions do exist for localized outbreaks in parts of the U.S.

This week CDC Dengue Branch and co-investigators in Texas and New Mexico reported a locally acquired, dengue-related death in the continental United States.  Although the patient died from a rare complication of dengue called hemophagocytic lymphohistiocytosis, this is the third dengue-related death ever in the United States.  Although our investigation couldn’t confirm where the case-patient was infected, she hadn’t traveled out of the country recently, so she must have been infected either in New Mexico, where she was vacationing before she got sick, or in her home state of Texas. This case was a startling demonstration that there may be more dengue in the U.S. than we realize, and that physicians should be on the look-out for cases.

What’s next

Aedes aegypti mosquito speciesThe burden of dengue in the Americas has increased roughly 30-fold since 1950, and one study showed that dengue-related hospitalizations in the United States tripled between 2000 and 2007.  So, dengue cases will likely continue to show up in greater numbers in the U.S. until we have a safe and effective dengue vaccine or other intervention to prevent dengue.  Moreover, two mosquitoes capable of transmitting dengue, Aedes aegypti and Aedes albopictus, are present mostly in the southern United States, but have recently been found as far north as Chicago and New York.  Therefore the possibility of local outbreaks in the U.S. after infected travelers return home is real.  Nonetheless, factors such as population density, frequent use of air conditioning, and other lifestyle differences that limit our exposure to Aedes mosquitoes reduce the likelihood of sustained dengue outbreaks in the continental U.S.  Therefore, Americans are more likely to get dengue while traveling in Latin America, for example to large international events like the World Cup, than they are to get dengue at home.  Nonetheless, new introductions of the virus will continue, some of which will result in local dengue outbreaks.

What to do about it

To protect yourself against getting dengue, be aware of the risk of dengue while at home or traveling to the tropics, as well as the prevention approaches you can take to avoid mosquito bites (regular use of mosquito repellent, staying in buildings with air conditioning and/or window screens, seeking medical care if experiencing a fever during or soon after travel).  Residents of states where Aedes mosquitoes are present can reduce their risk of spreading the virus by disposing of, emptying or covering water containers that serve as mosquito breeding sites (e.g., trash, discarded tires, kiddie pools).  These strategies reduce the chances that a returning traveler could get bitten in the U.S. and create a local outbreak.  Lastly, having a pre-travel health care consultation with your health care provider or a travel medicine specialist can provide additional information about dengue and other travel-associated risks that weren’t covered here.

Although the world is preparing for the introduction of a dengue vaccine, it is likely to be at least a few years before one is commercially available.  Until that time, dengue will become more and more familiar to Americans, both at home and abroad.

In a fish-eye’s view, tourists peer down at aquarium fish…



In a fish-eye’s view, tourists peer down at aquarium fish in Miami, Florida, 1963.Photograph by Winfield Parks, National Geographic