I think the man has Guinea worm disease (dracunculiasis) from drinking contaminated water somewhere in Africa. The adult worm which is under his skin has probably released its larvae into the water the man was using to soothe his painful foot. These larvae would normally be eaten by water fleas, people drink water containing the fleas and the cycle continues. It may take up to a year for the larvae to become full adults. There are no drugs to treat the disease and the only option I am aware of is to slowly pull the worm out through the wound and wrap it around something like gauze or a stick. It may take a week or two to get the whole worm out. CDC reported that in 2016 only four countries had local cases: Chad, Ethiopia, Mali, and South Sudan and that the number of cases have gone from 3.5 million per year in 1986 to 25 in 2016. Wow. It’s through the efforts of people like Jimmy Carter and the Carter Center that have made this disease well known by airing TV ads in the USA and I hope he lives long enough to see it eradicated.
I hope this improves my dismal record for answering case studies.
Mike in Oregon
Dear TWIP titans,
Based on the torrents of praise that issue from emailing listeners from around the globe, I may well be alone in my lack of enthusiasm for the regular feature of clinical case studies featured on your most excellent podcast. While I truly appreciate its value to listening clinicians in the management parasitic disease. While I hold the kind Dr Griffin in the very highest esteem, I find that the time lavished on the case studies gouges too deeply into the exploration of nonclinical parasitism that enthralled listeners in the Golden Age of TWIP. Am I the only TWIP addict who is curious about the protostrongylid lungworm, Umingmaksrongylus pallikuuhkensis, that troubles the proud muskox? Is no one else fascinated by Melampyrum arvense, a hemiparasitic flower whose defensive glycoside protects mice against liver damage by carbon tetrachloride? And what of Myxobolus cerebralis, that appears to cause the dreaded whirling disease in brook trout, and whose spores resemble an asterix? I may have missed one or more of these in the unheard archives, but by and large these natural wonders are passing us by, obscured in the glare of people’s parasitic pestilences. I hope that at some time in the future, general economic development will render the prevalence of parasitic disease low enough for clinical focus to be safely relegated to occasional attention.
Having gotten this long-simmering gripe off my chest, and hoping to be win a copy of your intriguing tome, I would like to offer my very first guess. I believe the Queens resident who enriched my country upon his arrival from Africa was accompanied by Dracunculus medinensis, AKA Guinea worm. When he soaked his foot, the little lady thought her opportunity had come at last, to release her eggs into cool open water. She began her unexpectedly long journey when, as a larva, she was eaten by a tiny crustacean of the genus Cyclops. Her host was ingested in turn by our new neighbour, where she met her mate. Tragically widowed, she made her way to the skin and bided her time. A year later, she prepared her exit blister, and the rest is history.
Home care will entail gently drawing her out of the wound over a period of up to several days, winding her long body around a cylinder, a little at a time. Asclepius would approve.
Dear D-G-R Trio,
I’m writing this on the first full day of Summer 2017 where I’m 1/3-rd of a mile from the Pacific Ocean on California’s Central Coast. I’m avoiding the double and triple digit heat wave currently scorching inland California.
For long-time listeners this case was a “no-brainer” from the Dickson-Vincent Duo’s original presentation of many families of parasites. I think of these shows as “TWiP – The Original Series”.
You two’s knowing banter riffing on the image of winding the worm coming out of the lesion on the patient’s foot onto a piece of wood, harkens back to the parasite covered on episode 37. I commend all fans to check that show out again.
The patient in TWiP 135’s case study is suffering from Dracunculiasis caused by Dracunculus medinensis, aka the Guinea Worm.
Indicators were the man’s description of a painful, burning-feeling blister on the foot, the patient sticking his foot into a bath of cold water, the blister bursting open and the patient observing something moving around in the wound.
Daniel presented two additional questions to listeners to answer:
Q1: WHERE IS THE MAN FROM?
A1: Short answer: the man is from Ethiopia.
The ‘TL;DR’ (too long; don’t read) analysis follows.
The patient is reported as living in the U.S. for nine months, and previously living in a rural, resource poor region of his country before emigrating. Dracunculus is spread in dirty water where larvae and larvae-bearing copepods accumulate from Dracunculiasis suffers comforting themselves by placing their feet/legs into cool water in streams or ponds.
The Carter Center has been instrumental in mounting an eradication campaign against Dracunculiasis. They publish regular status updates on their web site. In a January 2017 news release the Carter Center reports only three countries – Chad, Ethiopia, and South Sudan – reported, respectively 16, 3, and 6 new cases of Dracunculiasis. (https://www.cartercenter.org/news/pr/guinea-worm-worldwide-cases-jan2017.html)
By some searching via Google I found U.S. immigration statistics from 2015. From these countries they are:
South Sudan 127
Based on the huge number of emigres from Ethiopia it is almost certain that Ethiopia is the patient’s country of origin. As a check, let’s do some basic statistics and explore the probability that an individual from any of these countries had the parasite.
Adding country population data, in Excel I construct the following table calculating the incident rate per person. Multiplying by the number of emigres yields the expected probability an emigre from that country was infected.
Country Cases Population Incidence # emigres Probability U.S.
(2016) (000,000’s) (/person) patient infected
Chad 16 14.04 1.14E-06 75 8.55E-05
Ethiopia 3 99.39 3.02E-08 11,394 3.44E-04
Sudan 6 12.34 4.86E-07 127 6.18E-05
The country whose émigré had the highest probability of infection is Ethiopia.
I am mixing data from different years to make these “back of the envelop calculations”, however perfect data for each year is not available to me. This adds additional uncertainty around the probability assessment. Would I be surprised if the patient were from a different country? No. Why? Events with small probabilities do occur, they are just less likely to do so.
Q2: FOR HOW LONG WILL PATIENT REQUIRE DAILY TREATMENT?
The CDC’s web page “Parasites – Guinea Worm Management and Treatment” reports “There is no specific drug to treat or prevent GWD”. The illness requires daily management consisting of: gently pulling on the worm to remove it from the leg, wrapping extracted length on a spindle of some sort to maintain tension, cleaning the sore to prevent infection, doing it again the next day all while be careful not to break and kill the worm to avoid other complications.”
In “Parasitic Diseases 6th ed” (p. 302) Despommier, et.al. write treatment may last 3-10 weeks. No wonder there was consternation over how long the man’s daily treatments would take.
If the Carter Center is successful with its efforts to eradicate this parasite then this show is a unique opportunity to vicariously engage with this soon to be extinct parasite. I’m attaching a screen grab image showing treatment which I took from the Carter Center’s website.
Hello TWiP team,
I am a recent TWiP convert and am thoroughly enjoying the episodes! I am PhD student in biological anthropology studying how lifestyle factors influence soil-transmitted helminth infection patterns among the indigenous Shuar of amazonian Ecuador. I travel to Ecuador each summer and collect fecal samples to diagnose STH infection and then help treat infected study participants. I am specifically interested in how lifestyle change in this population alters infection risk. Your podcast has helped reinforce the material I’ve learned in my parasitology courses and I’ve had a lot of fun trying to diagnose the case studies.
I would like to submit a guess for the most recent case study from episode 135. I believe the patient suffers from Dracunculiasis, or a guinea worm infection. He would have acquired this disease by drinking water contaminated with larva-infected copepods. Once consumed, the larva exsheath in the host duodenum, burrow through the mucosa, molt twice, then reside in the liver, subcutaneous tissues, or body cavity where they mature in 8-12 months (this is why it took so long for symptoms to become apparent after the patient moved to the U.S.). The mature males die and degenerate after fertilization, but the mature female is fertilized about three months post-infection and gravid females migrate to the subcutaneous tissue, causing the appearance of an open ulcer and a burning sensation. Infected individuals often seek out cool water to relieve the pain and contact with cold water stimulates the female to eject larva into the water (the female may then be visible as was observed he
re). Once in the water, the larva infect copepods and are subsequently transmitted to future human hosts.
Dracunculiasis treatment involves the slow and careful extraction of the female using a small stick. The female is wound around the stick (a few centimeters a day) until fully removed. This process is slow to ensure the worm does not break, which would allow the larva to escape into the subcutaneous tissue and cause further pain. In fact, some scholars contend the caduceus (the emblem of the medical profession depicting a pair of serpents wrapped around a staff) originates from this ancient treatment. The drug metronidazole can also be used.
This disease is extremely rare because it has been the target of intense efforts to eradicate infection through education and the implementation of water filtering techniques. The Carter Center in particular has focused on these efforts, and as a result Dracunculiasis is almost entirely eradicated. Based on the very limited cases diagnosed this year (according to the Carter Center), I would hazard a guess the patient is from Chad, which seems to contain the last pocket of this disease.
Thanks again for all you do, keep up the good work! I’ll definitely be downloading several of your old episodes to help keep me entertained during my travels and work in Ecuador this summer!
All the best,
Theresa (Eugene, Oregon)
Dear esteemed hosts
I confess! I have lapsed in my TWiP responses – I was going to reply to the “beaver fever” case, but time was short. However you have raised the stakes and I couldn’t miss a chance to get your textbook in hard copy.
This case sounds like a classic presentation of the guinea worm Dracunculus medinensis: a parasite on the verge of eradication.
Recent cases have only been reported in Chad, South Sudan and Ethiopia. Infection occurs when a person drinks water containing copepods that have ingested Dracunculus larvae. The symptoms are caused by the fertilised adult female migrating through subcutaneous tissue. New larvae are released when the painful ‘burning’ blister is placed in water and ruptures.
There is no available treatment other than to pull the worm out slowly by a few centimetres a day, to avoid leaving parts behind. I had been told that giving oral metronidazole might ease this process but would value your collective wisdom on this.
The extraction can take many weeks as the female adult worms may be 1 metre long.
Your book reminded me that this parasite is likely to be the origin of the rod of Aesclepius: an ancient symbol of medicine.
Keep up the good work!
Your offer of free stuff has convinced this broke second year marine biology undergrad to have a go at one of your case studies. And although I’m probably the least qualified person to answer this I think I know the answer.
Before getting into my answer I’d like to say thanks for all the work you guys put into the TWiX podcasts. I find your podcasts help reinforce things I’ve learned in an enjoyable way along with new insights and literature recommendations.
My guess is Dracunculus medinensis or “Guinea worm” due to the distinctive symptoms described by Daniel (painful blister on the foot and the pain relief and rupturing of the blister in water), and dixons comment about the disease being a lot less common than it used to be, down to only 126 recorded cases in 2014. The patient probably lived in Africa prior to moving to the USA. Guinea worm infections take about a year to develop after initial infection from drinking water containing copepods infected with larva. This fits with the 9 months the patient has been in the USA.
Daniel posed the question how long would it take to treat this patient. He mentions that the worm was wound around a stick, this is the standard treatment for a Guinea worm infection. The worm is wound out of the wound slowly over a prolonged period (a few days to weeks in some cases as adult female worms may be 100cm long) of time to avoid breaking it. If this treatment fails the only other option appears to be surgery.
Sources – CDC website, Parasitic Diseases 6th edition
Ps. In the unlikely event that I win and it isn’t inconvenient could I have the book signed? And thanks again for all the work you do!
I would like to toss my proverbial hat into the ring to win the wonderful prize of knowledge as a reward to correctly guessing the case study presented in TWiP 135.
I believe the man seen by Daniel’s colleague has come face to face with none other than the fiery serpent of the Israelites! These organisms are not burning snakes, however – they are a parasitic nematode known as Dracunculus medinensis – or the guinea worm.
The organism is contracted by the human host through consumption of water containing copepods hosting the L3 larvae of the nematode. The larvae are released following the copepod’s death, and penetrate the stomach and intestinal wall where they mature and reproduce. The male worms die, while the female worms migrate to the subcutaneous tissue and after a stunning one year post-infection, the female causes a painful blister on the host (typically on the leg or foot, but there have been instances of blisters forming on the hand or scrotum).The blister ruptures and the female worm emerges, causing severe pain and irritation, and in order to find relief from the pain, the host will submerge the afflicted extremity in water, where the gravid female expels her L1 young into the water. These are consumed by copepods, where they develop into the infective L3 stage and the life cycle begins anew.
Due to the long incubation period between infection and the development of the blister, the man infected most likely contracted the parasite a year before the blister emerged, which fits his timeline of having only been in the United States for 9 months. The telltale wrapping of the worm around a stick (which inspired the caduceus) also indicates the identity of the parasite quite nicely. As to this man’s origins, there are only a few countries with reported cases of guinea worm, as this parasite is coming nearer to extinction. The four endemic countries are: Ethiopia, Chad, Mali, and South Sudan, so it is hihly likely the man came from one of these countries.
As for the treatment of this disease, there is currently no medicine or vaccine available for dracunculiasis – carefully wrapping the adult female around a stick and slowly extracting the parasite works best for removal. Extraction time can vary between hours to weeks depending on the length of the worm and point-of-care decision making by the physician. However, secondary bacterial infections must be dealt with using antibiotics and the pain/swelling of the worm removal should be managed with ibuprofen or aspirin
A signed copy (from all three TWiP hosts, of course!) of either book prize would be a great addition to my collection: I own a copy of Parasite Rex signed by Carl Zimmer and quite a few records signed by their artists.
Thank you once again for the informative and entertaining podcasts.
Molecular Helminthology Lab, Cummings School of Veterinary Medicine
Long time listener, first time emailer here. I am going to matriculate into the Texas A&M Medical School class of 2021 in just under a month and have been listening to your podcast for almost a year since taking my first Tropical Infectious Diseases class from Dr. Eric Brown while getting my MPH in Epidemiology at UT Houston and doing my practicum at Baylor, working with Chagas’ disease. I guess I will start with how I became interested in parasitology as it is quite an unique story.
I first became interested in infectious diseases after almost dying from a nasty case of Falciparum malaria when I was 18. I had taken a month long trip to Kenya to help build a medical clinic in a rural village on the shores of Lake Victoria. About a week after returning I started having terrible muscle aches, like I had run a marathon without training, followed by terrible shakes and fever. At the time I wrote it off because I would temporarily feel better and think that I had recovered. After a week of cyclic illness I went to an urgent care doctor who told me that it was probably just a “travelers illness” (whatever that is supposed to mean) and that I would get better on my own. He took some blood but insisted that the illness would resolve without intervention. Another week goes by and I am getting progressively worse, but luckily I have a standing appointment with my rheumatologist (I was diagnosed with Rheumatoid arthritis when I was 13) who requested the blood test results from the UC doc. I told my Rheumatologist that I had since noticed that my urine was turning the color of coke during my episodes. I’m not sure that this has been mentioned on the podcast previously but Falciparum malaria is sometimes referred to as “Black water fever” because of this unique symptom. My stomach was also killing me all of the time, so much so that between that and the muscle pain around my throat I could hardly eat anything. Over the course of my illness I lost about 15-20% of my body weight. He decided that we needed to repeat the blood tests because according to the UC report my white count was slightly elevated, but barely out of normal range. The next day I received a sort of panicked phone call from one of the office workers saying that I needed to come back immediately for a retest because there was an “issue” with the previous test. Apparently in the few days between my UC visit and my rheumatology appointment my Hematocrit levels had dropped from 42% (normal) to 25%. I was immediately referred to a hematologist/oncologist. Once I was finally able to get in to see him he initially told me that he believed that I had LEUKEMIA! At this point my hematocrit level had dropped to 13%. After insisting that he explain to me why leukemia would make my stomach hurt, he finally did an abdominal exam. It turns out that my severe stomach pain was caused by my enlarged spleen, which was about 3 times normal size at this point. It was so large in fact that when I laid down you could easily see it through my shirt. He was “intrigued” and so decided to do a blood smear “just in case”. After looking through many slides he finally found the culprit, a cell with the nasty little parasite nesting inside. He said that it was the only time that he had seen a case of malaria since being out of medical school. Luckily, this was during one of my “up” periods and I was able to walk myself across the street to the hospital and admit myself. The lady at the front desk had to call the doctor to confirm that they had indicated the correct diagnosis because here I was, a seemingly healthy young lady in San Antonio, TX, saying that I had malaria…In her defense, my parents didn’t believe it either. They came to see me in the hospital and thought for sure that they had misdiagnosed me because I looked fine. Within about 30 minutes of them arriving at the hospital I was trembling so bad that I couldn’t even hold a cup of water without spilling it. Soon my fever was spiking again and my hematocrit level was still dropping. Before it was all said and done I had had 3 blood transfusions, lost about 18 pounds and spent about 2 weeks in the hospital because of different complications. Oh and did I mention that there was a nation wide shortage of the standard treatment at the time? So I was substituted Malarone for the time being until I could get primaquine, which was months later. It took a couple of months to fully recover and gain all of my weight back and stop losing my hair (I guess a reaction of my body under extreme stress). I often think back on your “One in 3 million” episode and what would have happened to me if my illness had gone any further.
I often tell people that it was the worst/best thing that ever happened to me. I don’t usually have to explain why it was the worst but I say it was one of the best things because that experience left me heavy heart and a new found passion for medical missions. That trip really sparked something in me that I just really can’t shake, a thirst for medical knowledge, interest in tropical infectious diseases and a desire to provide care for those that otherwise would not ever get it.
Now here I am, a couple degrees, many applications and 6 years later, a month from finally starting medical school. If it weren’t for these experiences or looking in those children’s eyes 6 years ago, knowing that some of them wouldn’t live to see their next birthday, that their mothers were willing to riot in the street to get mosquito nets to protect them, that I was a rare case of malaria here in the states, but 3 million people die from it every year, I don’t know that I would have persevered this far. It has been a long, sometimes very disappointing and emotional road but every step was worth it because I knew that eventually I could make a difference.
Sorry for the incredibly long email, but I thought I would share as that experience has given me a unique perspective into what some of my future patients have been through.
I will make the rest of my email short as this case was an easy one (at least I think… If I’m wrong y’all can just skip this part to save me my dignity).
Even with the very basic information provided, it is clear that the patient is suffering from Dracunculiasis, an extremely rare infection by the nematode Dracunculus medinensis. I knew this pretty much as soon as I heard “burning blister”. This disease is almost completely eradicated, largely due to the efforts of former president Jimmy Carter and the Carter Center. All current cases originate in Sudan, chad and Ethiopia. Chad was at one point free of guinea worm, but it is thought that the worm was reintroduced by undercooked fish.
Treatment would include supportive care once the worm emerges. The foot needs to be placed in a bucket of water, which can later be treated before being discarded. This signals the worm to emerge and release her larvae. A stick would then be wrapped around the end of the worm. The patient or a health worker would continue to wind the stick to slowly work the adult worm out of the opening. This may take up to a week to pull out the entire organism.
I would be very interested to know what country this man had come from as there are currently only a couple dozen cases a year.
Thanks for doing what you do and inspiring a future generation of parasitologists!
The man living in Queens has come down with a case of Dracunculiasis, or Guinea Worm. He became infected in his previous country, likely Chad or South Sudan. Given the troubles in South Sudan, I would guess that this is where the patient is from. It is certainly in a resource limited region, and I imagine that contaminated water supplies abound, given the scarcity of practically all necessities. I’m happy he made it to Queens.
As to the question of care, apparently all one can do is wrap the worm around a toothpick or some such implement and, very carefully, wind the animal around it like some piece of diabolical spaghetti. As the text* states, wound care and pain management will be the components of his treatment going forward. How long will he require it? Hopefully no longer than a week. I see now the dilemma faced by the provider. Does this patient need a home healthcare worker to come to his residence to coax out the worm? Can the worm be extracted in this manner in one visit? Once free of the worm can the patient then travel to a wound care specialist for follow up care of the lesion, or will he require multiple home visits? I’m curious to hear what Dr. Griffin would recommend.
I have to say, if ever there was a classic presentation of Guinea Worm (albiet in Queens), this would appear to be it.
One last question: do we have any idea why these lesions tend to occur in the lower extremities? I know it is possible for them to occur elsewhere on the body, but the legs and feet seem to be where these things like to go to ruin someone’s day.
Much admiration to you all!
*Parasitic Diseases, 6th ed. Would love a bound copy!
I am offering my identification of the new resident of Queens’ horrifying foot tenant. It appears to be a Guinea Worm (Dracunculus medinensis). Our patient might have moved to NYC from West Africa where this worm is still present. The adult female worms form lesions on the lower extremities, which may open up when bathed in water, at which point she launches her eggs out into the world in search of new hosts. After seeing the image in Parasitic Diseases 6th Edition I can understand why the patient would need someone to see him rather than visiting a hospital for aftercare.
Depending on where the patient resides, trucking out to Queens might not be such a long journey. It’s not so bad to drop by Astoria, but Jamaica is a different story.
Hi Doctors Twip,
I’d like to take a guess at the case study for Twip 135. As it happens, the differential for my first Twip guess to Twip 123 (which I think turned out to be cutaneous larval migrans) included some reading about the incredible eradication work by the Cater Foundation in relation to this scourge.
My guess is Dracunculiasis or Guinea worm disease. The disease is contracted by drinking water contaminated with water fleas which are infected with Guinea worm larvae (Dracunculus medinensis).
In the body, the larvae mature and mate. The male dies and the female migrates to the limbs, usually to the feet. From ingestion, this process may take about a year. The patient in question has been in the US for about 9 months and so could have acquired the infection elsewhere.
The female moves to the surface of the skin and forms a particularly painful blister which feels like intense burning (hence the name Dracunculus or little dragons) which often causes the afflicted person (or animal) to immerse the afflicted limb in water for relief. Upon contact with water, the blister bursts, releasing hundreds of thousands of larvae, perpetuating the cycle.
Treatment involves bursting the blister in a controlled way (breaking the infectious cycle) and then extracting the worm by wrapping it around a stick or gauze. The process of extraction may take from hours to a week or in extreme cases up to three months and is debilitatingly painful. During extraction, there is a risk of the worm breaking and the remaining section causing further complications. It’s not clear that a patient could extract the worm themselves.
In 2016 only 25 cases were reported, down from 3.5 million in 1986. Those cases were in Chad, Mali, South Sudan and Ethiopia. According to the Carter Foundation’s June 15th newsletter “The Guinea Worm Wrap-up” (ahem), the only human cases this year were in Chad, with some animal cases (in baboons and dogs) in the other countries.
Given the almost incredible decline in Guinea worm infections since 1986, the familiarity of the patient with the worm/infection is probably entirely dependent on their age.
Sorry for the novel but stuff like the Carter Foundation’s impending success, the victory over smallpox, the impending success over polio and all that stuff really give me a warm glow.
Thanks and regards,
John in Limerick
(where it was a hot 29°C this week).
I was excited to hear the case study this episode since I have been following the Carter Center’s campaign to eradicate Guinea Worm disease. According to the Carter Center, in 1986, 3.5 million people a year were afflicted with Guinea Worm Disease. In 2016, there were 25 reported cases. Definitely a public health success story.
Guinea Worm is transmitted when someone drinks water contaminated with Guinea Worm larvae. The female worm then grows to a meter long in about year and emerges through the skin. This is a painful process and people often seek relief by submerging the painful lesion into water, stimulating the female worm to release larvae and continuing the infective cycle.
Guinea Worm Disease transmission is endemic in Chad, Ethiopia, South Sudan and Mali. However, in 2017, only Chad has had 5 reported cases so far. Guinea Worm eradication in Chad has been complicated by an increase in infections in dogs.
The WHO website states that 4 cases reported in 2017 were from four villages in Chari Baguirmi Region, Chad. So this is where I am going to guess our patient was infected with Guinea Worm.
Treatment consists of slow removal of the worm and prevention of secondary infection.
The life cycle of Guinea Worm is on the CDC website: https://www.cdc.gov/parasites/guineaworm/biology.html
I love all the TWIX but TWIP is my favorite. I have worked in a medical laboratory for almost 20 years as a Medical Laboratory Scientist and the case studies are the most exciting to me. I can hardly wait for the new TWIP to be released!
I am currently in a graduate program at Johns Hopkins School of Public Health in Spatial Analysis for Public Health. I think spatial analysis of infectious disease will become increasingly important in the future.
Thank you all for fueling my passion!
Hello Philosophers of TWIP!
Upon hearing the details of the case study of episode 135, I immediately remembered the first time I ever browsed through my downloaded version of Parasitic Diseases 6th Ed. (thank you!). I had to do a double take at an unusually, even considering the subject matter, gross image of a large open wound on a human foot, with a worm inside it. In my short career of trying to diagnose TWIP cases using this book, I’m learning that the pictures are often a great aid in coming up with a diagnosis.
Everything about the man in Queens with the foot blister that became an open lesion with something in it sounds characteristic of a diagnosis of Dracunculus medinensis. According to the experts who wrote Parasitic Diseases, Dracunculus infects humans who drink water contaminated with copepods infected with L3 larvae. The copepods release the larvae in the small intestine, who penetrate the wall of the small intestine, and migrate through the connective tissues of the host for up to a year, molting twice and maturing to adults. The adult female worm finishes her migration in subcutaneous tissue, often on the lower extremities, such as in this case. She uses her tail to anchor into the tissue, and secretes a toxin that induces local inflammation, causing a vesicle to form around her. This was the blister that the patient in the case noticed. This also causes an intense burning sensation, which is supposed to induce the host to dip the vesicle in water to find relief. When that happens, the water causes the vesicle to burst and the uterus of the worm to prolapse, eventually releasing L1 larvae into the water. Ah, the circle of life. Definitive diagnosis is by locating the head of the adult worm in the skin lesion and/or identifying the larvae that are released into freshwater. Treatment traditionally involves winding the worm gently around a thin stick to extricate it from the lesion. Removing the worm seems to be the least of his worries, unfortunately, as the wounds appear to be nasty, and often result in 3-10 weeks of disability. Wound care and pain management will form the bulk of his treatment.
It seems relatively likely that our patient has come from Sudan, or at least somewhere nearby. This infection has nearly been eradicated in most regions, but still occurs in South Sudan. This is also a region that has seen much recent immigration to the U.S. The worm has a relatively long period that seems to be symptom free as it migrates to the subcutaneous tissue, so it is likely that he was infected in his home country before coming to Queens. Until recently, it seems that it was a quite common infection, so I would guess that he probably had a decent idea of what it was, although I could be wrong.
Thanks for the interesting cases, please keep them coming! All the best,
Hi TWiP Team.
This Case Study sounds like classic Guinea Worm disease or Dracunculiasis caused by the nematode Dracunculiasis medinensi.
A person is infected by drinking water with contaminated with tiny crustaceans or copepods, also called water fleas carrying infective guinea-worm larvae.
The painful blister contained guinea-worm larvae that if released into a rural water hole could have been ingested by more copepods wherein they would mature to their infective stage and spread the disease to more people.
The adult female nematode may be 600 to 1000 mm long and will have to be carefully removed from the patients leg, traditionally this is done by winding the worm round a stick and slowly pulling it out a few centimetres at a time, taking care not to break the worm.
While alive this infection is largely symptomless, now that the nematode worm is dead it is no longer suppressing the immune system which responds to the body of the dead worm by causing painful inflammation.
According to the CDC:
“Sometimes the whole worm can be pulled out within a few days, but this process usually takes weeks. Medicine, such as aspirin or ibuprofen, can help reduce pain and swelling. Antibiotic ointment can help prevent secondary bacterial infections.”
As this patient is living in Queens and not in rural Africa, I wonder if surgical removal of the worm would be a viable option?
I am back. I am Toni from Spain.
Today in Zaragoza is partly cloudy and a maximum temperature of 28ºC.
Going straight to our interesting case study.
This case seems exceedingly easy for a microbiologist, describing a typical case of Dracunculiasis, caused by the nematode Dracunculus medinensis. This infection was much more widespread in the past, but nowadays only a few foci remain in a handful of countries, namely: Chad, South Sudan and Ethiopia. Being a francophone country, Chad would be the last on my guess-list. So, I guess our patient would have recently arrived from Ethiopia to the US. The disease is contracted by ingesting water contaminated with the water fleas (genus Cyclops). The burning /itching sensation is an example of a host-manipulation-behavior from the parasite, because these symptoms force the patient to seek some relieve with the “refreshing” water contact. In that very moment the female just release a huge amount of larvae into the water. These larvae somehow seek and find the copepods (water fleas) and the cycle is completed.
What is curious in this case is not the clinical presentation, but to observe this disease in the middle of NY, thousands miles away from the countries where it is endemic. Dracunculiasis is an archetypal example of poor-people-disease and I wouldn´t expect this poor people coming into the US, just because this disease strikes the poorest people of the poorest countries.
From a Public Health point of view this is a very interesting disease. It probably will be the first parasitic disease to be eradicated ever. The Carter Foundation is probably the most important actor in the history of the control for this disease. Only political issues have been delaying the goal of global elimination. This of course will be possible only because D.medinensis has only a human reservoir, at least until now. And just, when we are in the brink of eradication, another reservoir has been discovered. And a very important one, our best friend: THE DOG. At this point I want to ask to our experts several questions that have come to my mind:
- How is possible that we, humans, in the whole history, have never be able to detect any canine case before?. I mean:
- Is it really a new reservoir or a NEWLY DISCOVERED reservoir?.
- And if it is really a new reservoir, could the pressure exerted over the shrinking-nematode-population have led to look for alternative hosts?.
- From an eradication point of view I think these are very bad news. How do you think this could change the global eradication goal?.
- From a zoonotic point of view, how could we control the disease in the most remote areas where the disease is endemic? Mass treatment for the dogs? Water-collection fencing to prevent the contact between dogs and water? As far as I know there are not effective drugs…
P.S. I think our audience are parasite lovers. I love to read everything about parasites, among many other topics. I really, really enjoyed reading People, Parasites and Plowshares and several of Robert Desowitz books. So, I think it could be a great idea to share with the audience different books about ecology, parasitology.
I am anxiously waiting for the next episode.
Thank you very much.
Hi TWIP Team!
I am writing in from Davis, California where it is currently 89 degrees fahrenheit. A big improvement from the 105 degree days we experienced last week!
The case presented in episode 135 sounds like a classic case of Dracunculiasis caused by the guinea worm nematode, Dracunculus medinensis. It is a nematode that is transmitted to humans by consumption of water with infected copepods. After contaminated water consumption and the death of the copepods, the nematode larvae are released and penetrate the stomach and intestinal wall. They go on to mature in the muscles where females are fertilized and males die. The females then migrate to the extremities where they induce blisters and emerge! This whole process in itself takes a whole 9-12 months! (Lining up with our patient’s timeline) The burning pain from the emerging nematode causes the infected to seek water where the female nematode can release her youngins through ovovivipary! Once L1 larvae are released into the water they infect copepods, molt a couple times into an L3 larvae, and the whole cycle goes around again.
This infected man is most likely from Sudan, Chad, Mali, or Ethiopia where the remaining few cases are seen. Thanks to a large global eradication effort the number of cases has been reduced to 25 cases in 2016 from 3.5 million cases in 1986!! This simple control has been done primarily through the filtering of water through a nylon mesh and isolation from water of the infected.
The bad news for the infected man is that there is no effective drug treatment besides the use of an anti-inflammatory drug to ease the removal of the worm and some good pain killers! It could potentially be removed with surgery if worm is accessible but this risks an allergic reaction if not properly removed. The most common mode of removal is to very slowly wind the worm on a stick until removed. While painful and time consuming, the process of removing the worm is not difficult. If comfortable, the man can do this by himself everyday. In order to avoid secondary infection, however, the wound should be properly treated.
Interestingly, D. medinensis has been reported to infect canids, felids, horses, cattle, and non human primates possibly serving as reservoirs for the pathogen!
Thank you all for hosting this wonderful podcast! It is always a pleasure to listen in!
All the best,
UC Davis School of Veterinary Medicine
DVM Candidate | Class of 2021
PS I would love to add the hardcopy of Parasitic Diseases to my library!
Dear Doctors Twipping the Light Fantastic,
It took a few months, but I’ve finally listened to all the TWIP episodes in order. To celebrate I’d like to put my hat in the ring for an English version of the hard copy of Parasitic Diseases, 6th Ed.
Regarding the case study from TWIP #135:
The gentleman currently residing in Queens has a female Guinea worm (Dracunculus medinensis, Parasitic Diseases, 6th Ed, p299) in his leg.
This means that roughly a year before the blister appeared he ingested copepods infected with the worm’s L3 larvae. Since he’s from a rural, resource limited area, the infection source was likely contaminated water or undercooked fish / frogs.
My guess for the gentleman’s origin is Chad, somewhere along the Chari River. They’re dealing with canine outbreaks (carrying the apparently genetically identical human worm) in remote villages. Other possibilities are less likely (South Sudan, Ethiopia and Mali) as Chad’s the only country with reported cases in recent months. (I couldn’t find fine-grained demographics for Queens or travel rates from the top 4 suspects, so reported cases in the last year was the best I could do.)
Treatment is to keep the wound clean to prevent secondary infection, and to keep pulling that filarial nematode out a few centimeters per day, being very careful not to break it.
Since the adult females can range in size from 0.6 – 1.0 meters, and removal rate depends on what it’s wrapped around inside the leg, there is quite a bit of variability in how long we can expect the gentleman to have to do this.
The CDC’s website (https://www.cdc.gov/parasites/guineaworm/gen_info/faqs.html) says that
Once part of the worm begins to come out of the wound, the rest of the worm can only be pulled out a
few centimeters each day by winding it around a piece of gauze or a small stick.
Sometimes the whole worm can be pulled out within a few days, but this process usually takes weeks.
I first heard about GWD in a youtube video about Neglected Tropical Diseases: “Kurzgesagt – In a nutshell”: https://youtu.be/qNWWrDBRBqk?t=2m3s
TWIP 37 was recorded earlier, but I’m late to the TWIP party so thought I’d share that tidbit.
Thank you very much for these excellent podcasts. Many future generations will be educated and entertained by your informative discussions and joyful enthusiasm for a long time to come.
A note about the writeup in Parasitic Diseases, 6th Ed: p302 under Treatment: There’s reference to figure 24.1, which is the wrong figure. It should probably be 25.1.
Ronald Jenkees is awesome! Thanks for introducing me to his music.
I could not resist the temptation of Parasitic Diseases and I am fairly confident with my guess. The gentleman has dracunculiasis caused by the guinea worm with his probable country of origin being South Sudan, Mali, Chad, or Ethiopia. These are the last remaining bastions of endemic guinea worm which with luck will be eradicated soon due to the efforts of the Carter Center’s eradication program.
The “worm around a toothpick” was a dead giveaway and immediately made me think of Dr. Despommier’s telling of the origin story for the “fiery snakes” on medicine’s caduceus from People, Parasites, and Plowshares.
Regards from Indianapolis,
PS I am a huge fan and have been listening to Vincent’s entire podcast empire for a few years. A habit which helped me to decide to return to graduate school for epidemiology and now consider to further my education at either medical school or a PhD program. Thank you for all that you do and I hope for many more years of listening to your stories and banter.
Hello esteemed doctors.
I am writing in for the case presented on episode 135. In fact, I’m currently attending the American Society of Parasitologists meeting in San Antonio, TX. Being a grad student, this is my first ASP meeting and I am thoroughly enjoying the company and the presentations. Finally, I have a room full of people as passionate about parasites as I am! Some day I will write in telling you about my thesis. But for today, let’s get to the case.
Listening to Dr. Griffin present the case, I started grinning from ear to ear (although not to be insensitive to the pain this man would be in) as the clues were very indicative of the parasite. My differential diagnosis would be that this man has had the misfortune to host a Guinea worm, Dracunculus medinensis. He would have picked this up from drinking water contaminated with copepods that were carrying infective larvae.
After doing some reading from the Parasitic Diseases 6th edition, I learned that it takes about 1 year from the ingestion of the larva for the female to migrate out of the intestines and travel down the leg where they create the blister. The burning blister is the worms way to ‘encourage’ its host to put its foot in water, so that the female can lay its eggs there and the life cycle can continue.
The Guinea worm infection is not fatal. However, attempts to remove the worm can result in an allergic reaction. Slowly pulling on the worm by wrapping it around the stick is a very old trick to remove the worm, but this is a slow, painful process. This could take up to 2 or 3 weeks of wrapping the parasite to get this long worm out of the leg. As Dr. Despommier has mentioned in the early episodes of TWiP, this wrapping of the worm is the inspiration for the medicine logo/crest found at many (or all) hospitals. Aside from this, there is nothing in the way of medication to remove the parasite. Some treatment to help with pain management and secondary infection risks. I hope the man had a quick recovery.
He most certainly would not have picked up this parasite living in Queens and would have brought it with him from his previous residing country. This man likely would have moved to the USA from northern Africa. The Carter Center website mentions 4 countries that the parasite has been observed in for the last few years and includes Chad, Ethiopia, Mali and South Sudan. The eradication program has been very successful to date and is closing in on no human cases. The fact that only 25 human cases were reported in 2016, it is very rare that one ended up in the USA!
Thank you for the time you put into making these wonderful and educational podcasts. Please keep the cases coming, and if possible I’d love to hear about more animal cases!
All the best,
Dear Drs. TWIP,
To me it sounded immediately like the horrible symptoms of the “fiery serpent,” Dracunculiasis or Guinea Worm Disease.
When I started working in Primary Health Care in the early 1980s there were an estimated 3-4 million cases a year in some 20 nations.
Best guess is your patient is a relatively recent immigrant from one of the four remaining endemic nations of Mali, Chad, South Sudan or Ethiopia.
The Carter Center, Gates Foundation and many others have worked so long towards GWD irradiation and I understand its down to a tantalizing score of remaining cases each year.
It was still active in Benin and Côte d’Ivore when I worked there nearly 20 years ago. I remember the hope that simple cheesecloth water filters (which can exclude the GWD infected copepods
from drinking water) would be the last nail in GWD’s coffin, but a bit like polio, we’ve realized it is more complicated. Now it appears humans and copepods aren’t the only species that can carry the “human” guinea worm, but also dogs and frogs, cats and catfish, as well as baboons.
This is an old and horrible disease, and the week or more that it will takes to slowly extract a guinea worm is agonizing. And as with anything this painful and debilitating, it has been recognized and written about since Greek and even Biblical times. Dickson or Daniel could talk about the Rod of Asclepius better than me, as well as the downside of topical antibiotic or anti-helminths. But almost certainly your patient, at least growing up, would have seen others suffering from this infection and would suspect its what he has.
I know we all join former President Carter in hoping we live to see the day when this disease is gone.
Mahalo for the best podcast out there
and keep up the fantastic work you’re doing!
Weather here is 30ºC or 86ºF, sunny in the mornings with showers most evenings this time of year.
Enjoying our kids home for the summer.
Why don’t you three come do a Rat Lung Worm workshop on the Big Island? We’ll host you, put you up for free, and you can do a live podcast from Kona?
University of the Nations
I didn’t think I would ever be able to submit a guess to one of your cases unless the clue was something like “the answer rhymes with ‘grape perm’ and is sometimes found in undercooked pork and is rumored to be used as a diet aid”.
I think this poor man has a Guinea worm, the horror!
According to the CDC website the fact that the gentleman put his foot under water encouraged the worm to come out. I am guessing this is the reason why people that are infected with Guinea worms are not allowed to enter drinking water sources.
The treatment per the CDC:
The wound will need to be cleaned and then gentle traction applied to the worm to slowly pull it out until resistance is felt, being careful not to break the worm. Since these worms can be up to a meter in length I don’t think the toothpick is going to be enough.
The tension caused by the stick or toothpick is to encourage the worm the to come out.
Topical antibiotics should be used to prevent bacterial infections.
It is recommended to change the the bandage every day and aspirin or ibuprofen taken for the pain.
These steps are to be repeated until the whole worm is pulled out. Which can take several days to weeks.
This gentleman would have to have stronger intestinal fortitude than I would ever have in a billion lifetimes to do this on his own. I am not sure who would volunteer to go to Queens to help the patient but maybe he could be hospitalized. (I know, this would never be allowed)
The patient has been living in Queens for the last nine months and Dr. Griffin said that this was a recent case. I am going to guess that he did not pick up this worm in Queens because according to the The Carter Center’s website there haven’t been any cases of Guinea worm infections in the United States in 2016/2017 (until now?)
In 2016 only three countries reported human cases of Guinea worm: Chad, Ethiopia and South Sudan. This report is from January 2017, the totals may have changed. Perhaps this patient is from one of these countries.
I don’t know if I’m right or not but if I’m right does this mean that there has been a case of Guinea worm found in the US and The Carter Center will have to change its charts/totals?
In researching this case and I found that it is quite an incredible achievement of President Carter to have made the world wide eradication of Guinea worm a goal. It has almost been achieved. Quite amazing indeed!
There you have it, my first guess I may be wrong but I must say that now my skin is crawling! 😱 I really must want that book so I can have new and improved nightmares.
It is 65°F/18°C up here and partly cloudy Seattle. Where we are just north enough to miss the total eclipse!
p.s. again thank you for all you do. I really enjoy your podcast, maybe not finding out there is a such thing as a stool chart, and the others podcasts too!
p.s.s. sorry for the typos but as I said my skin is crawling and I need to finish this so I can go get something to drink to calm my skin and nerves down, it has taken me hours to write this little bit.
Some may say that you have gone too far in an attempt to attract more listener’s letters by dumbing down the difficulty of the diagnostic puzzle, but I will not say that.
Instead I will submit my guess.
Despite a worldwide effort to eradicate the dracunculiasis it is still a problem in Chad, Ethiopia, Mali, and South Sudan due to poverty, political instability and stray dogs. It is almost gone in Nigeria. That is where the patient must have come from.
The unfortunate Queens resident must have drunk water with larvae-carrying water-fleas, brought the Guinea worm in himself and watched the creature with amazement, trying to get out from his foot. The doc saw the head coming out first. Now the trick is to carefully take the worm out without breaking it into pieces. Do not use mebendazole! the worm is wanted alive. Only worry about extracting the worm completely and treating the wound, pain and potential allergies.
I have not idea how they do it in Queens.
Keep up your excellent work and be nice to Dixon.
Today I’ll be brief, after my last time-monopolizing monologue, which I could not help think caused a bit of discomfort to the subject of my eulogy, and for that I apologize.
I believe the last case described a Dracunculiasis or Ginea Worm infestation.
“In 1986, there were 20 countries where Ginea Worm was reported. These amounted to about 3.5 million cases per year. 90% of the cases occurred in Africa. At that time an additional 120 million people of that Continent were at risk for GWD because of unsafe water supplies”, the World Health Organization reports.
Great progress has been made in the last thirty years. GWD is now poised to be the next disease after smallpox to be eradicated. As of January 2017, the International Commission for the Certification of Dracunculiasis Eradication (ICCDE) has certified 198 countries, territories, and areas, as being free from GWD transmission, with only 8 countries remaining to be certified: Kenya and Sudan are in precertification state; Angola and the Democratic Republic of the Congo are countries not known to have Dracunculiasis but yet to be certified, and four remain endemic countries: Chad, Ethiopia, Mali, and South Sudan.
Therefore, regarding the question “where did this patient came from”, it may depend on the year when this case was diagnosed by Professor Griffin’s colleague. Probably South Sudan or Ethiopia (I consulted the data at the Migration Policy Institute and the numbers seemed to point for a larger probability of these two origins).
Adult female worms come out of the skin to shed eggs in the water. It is then that the parasite may be pulled out (very gently) and fixed in place with a small stick, or with other object. As the female can be up to 170 centimeters long (no idea in furlongs, smoot, paces or the other exotic units the Axis of Medieval insist using), and usually one can only pull around 1 centimeter per day, the extraction can be prolonged to 170 days, that is to say it can be a process of more than 5 months.
The disease causes preventable suffering for infected people and is a financial and social burden for affected communities. The efforts of the CDC, WHO, UNICEF the Carter Center and Bill and Melinda Gates Foundation have been paramount in the eradication of this plague.
Meanwhile, genome sequencing has confirmed that dogs in Chad are infected by the same nematode worms (Dracunculus medinensis) that plague humans (M. L. Eberhard et al. Am. J. Trop. Med. Hyg. 90, 61–70; 2014). This is very upsetting as it can mean that other potential hosts and reservoirs of the parasite may exist and continue to act as spread foci, delaying the total eradication of the disease. Nevertheless, it poses the opportunity to show how important it is to continue research on these diseases, that are known for so long, but at the same time keep having so much learn about.
Hello TWiP hosts,
Writing from the island of Puerto Rico with clear skies and 83° F at 8:30 p.m. Recently I discovered your podcast and I must say it has been helpful for my commute to work which is around 1 hour away from my home. Since I have been hearing on average an episode a day I must say this week has been somewhat curious because the last 4 cases have ended one way or another in you guys discussing the patient’s stool. Nevertheless I enjoy the discussion and your dynamic, and hope to hear more interesting cases.
Now on to case study 135. The moment you started mentioning the painful blister with a burning sensation followed by it bursting when it was entered in water showing a parasite inside which the parasitologist wrapped in a toothpick I remembered seeing this on TV. The parasite, which is Dracunculus medinensis also known as Guinea worm are found in feshwater and are ingested when drinking unfiltered water. The reason the blister is formed is because once the female has matured and reproduced it needs to return to the water to deposit their larvae (Hope Dickson explains the detailed cycle). The patient should have been from New Guinea since its the country from which he worm gets its name from. Treatment should take around a week. The reason for this is because the worm can only be removed using a matchstick little by little until it presents resistance and wait until the next day before resuming the removal. It must be prevented that the worm breaks because it could cause an allergic reaction and/or infection. The only prescription for the patient in this case should be a topical antibiotic to prevent infection in the wound since apart the matchstick method. Hope this helps in general.
Keep on the good work,
Dear parasite pals,
Thanks to your podcast, I knew exactly what this was! (Attached photo.) So I thought of you and decided to write in.
The man in Queens has Guinea worm, which is nearly eradicated. There are still cases in Mali, South Susan, and possibly Chad where many dogs seem to be infected.
Finding a case imported into New York must have been a shock given how few cases are left in the world! I Googled “Guinea worm case New York” and didn’t see any press coverage about this case. Do you know if rare infectious diseases like this are routinely reported to CDC or elsewhere? I suppose it would be hard to keep the patient anonymous in this situation, being perhaps the only case for thousands of miles. But in general — How do we keep tabs on potential emerging epidemics here in the US when doctors see unusual things that they think are contagious?
Thanks for all that you do!
Dear TWiP Team,
Just a quick letter today to deposit my case guess for episode 135 involving the gentleman from Queens with a burning desire to soak his foot. This seems to be a clear-cut case of the ‘Guinea worm’ Dracunculus medinensis. In 2016, only 25 cases were reported out of Chad, Ethiopia, and South Sudan. Treatment involves slowly winding the worm “a few centimeters a day” on a stick and wound care to prevent secondary bacterial infections. Care must be taken not to break the worm. Female worms can be up to 100cm long, which mean this process could take weeks or even months depending on the length of the worm.
Thanks for the amazing podcast and the opportunity to win a copy of the Parasitic Diseases! I really loved the case from episode 130 (spider bite). I saw something very similar while shadowing an ID doc in rural Illinois.
UCSF School of Medicine
Class of 2021
I kept delaying my response, so I hope I’m making it in time for the recording of episode 136!
My guess for the case study is an infection with Guinea worm (Dracunculus medinensis). The female worm is emerging from the man’s foot, searching for a water body into which she will deposit her offspring, which will then be taken up by the copepod intermediate host. The man must have come to Queens from a subsaharan African country (maybe Sudan, Mali, or Chad?), where he would’ve contracted this infection by drinking up an infected copepod with his water (should’ve used Jimmy Carter’s straining straws!). This worm will be emerging from the man’s foot for several days, maybe even a couple of weeks, so daily care of driving to him to wrap the worm around a stick would be somewhat arduous for a full-time doc. It is possible that he could wrap the worm himself, but it seems risky to me since he will be in pain at the wound site and may risk ripping and killing the fragile worm if he gets impatient. If he does this, he then risks greater injury to himself from his own immune system’s reaction to the dead worm in his body, possibly including anaphylaxis and death.
I am a student of parasitology, doing my Master’s thesis work on the systematics of an acanthocephalan (a.k.a. thorny-headed worms) genus that parasitizes fish and turtles. I still remember learning about Guinea worm in high school and it being my first inspiration for turning my general biology sights toward parasitology. What a crazy worm!
I am a member of the American Society of Parasitologists and recently attended the annual meeting in San Antonio, TX (June 27-July 1), where there were lots of great talks by students and PI’s about an incredible range of parasitic infections and diseases. I would like to reiterate what all of you said on an episode back in 2015 in reply to someone casting about for graduate school options that conferences are a great way to meet potential advisors and to get inspired about understudied areas of any field. They are, and it was! If people are interested in getting involved with ASP, they will be updating the website over the next year or so, so it should hopefully be an easier interface for those looking to navigate the site and find out more. There are also several regional conferences associated with ASP scientists, if the national meeting is inconvenient.
Thank you all for doing what you do,
Writing from Washington, D.C., where it is a balmy 25 degrees Celsius with 74% humidity at 9:25am, set to get up to 32 degrees C.
Biology M.Sc. Student, SUNY Oneonta
Good Day Twippers Vincent, Dickson, and Daniel!
The weather here in Mesa Arizona (a suburb of Phoenix) is ghastly; a horrid 42 C (108 F) with 30% humidity. In my opinion, the man from the case study on episode 135 has the text book diagnosis of Dracunculiasis, or more commonly known as Guinea Worm. Every symptom fits, from the delay of symptom onset, the blister, the relief upon submersion, the worm wrapped around the toothpick… all of it. The treatment is nothing more than our average NSAID and removal of the worm which unfortunately can take weeks to complete. With the help of the Gates foundation, this parasitic infection has hit an all time low, but we (the world) still have cases reported every year. As of 2016 most (16) were reported in Chad Africa.
I thank you for your podcast and can’t get enough of the whole TWiX series of podcasts!
With the highest regards,
Steven a Medical Technologist in Scottsdale AZ