From Portland, OR where high is 3C and low was -4C.
Either this one is so easy, that there’ll be a couple dozen correct answers, or I’m way off.
Internet search for “mass drug administration parasite” shows there are three parasitic diseases being addressed in this way: Schistosomiasis, Malaria and Onchocerciasis.
Diagnosis of Schistosomiasis is done through examination of stool and urine, so not that.
Diagnosis of Malaria is done through a blood smear, so not that.
Diagnosis of Onchocerciasis is done through skin snip – check.
Onchocerciasis often causes intense itching, and results in patches of hyper-pigmentation and depigmentation – check and check.
Onchocerciasis often has hard, subcutaneous nodules, most commonly found on head in South America, and near the groin in Africa – check.
Blindness, due to onchocerciasis often begins with myopia – check.
Hence, my ‘diagnosis’ is onchocerciasis, due to O. volvulus infection from black fly bite.
Treatment (according to CDC) is ivermectin to kill larva, and doxycycline to kill Wolbachia bacteria that the adult worms depend upon.
One caveat, the parasitic worm, Loa loa, can also result in itchy skin, and is common in Ghana, although I find no reference to blotchy pigmentation, or specificity for the groin. The nodules of loiasis migrate, instead of staying in place. Also, L. loa can infect eyes, but I find no reference to it causing blindness. Even though the symptoms don’t match loiasis, I’d run a PCR on the skin snip, or look at a blood smear, or do an antibody test, just to rule it out, as those with Loa loa, when treated with ivermectin, can develop encephalopathy. If it is loiasis (doubtful), treat with diethylcarbamazine.
While loiasis should be ruled out before treatment, I still think it is river blindness, onchocerciasis.
Good evening sages of knowledge from Sydney Australia where it hasn’t stopped raining in a week.
First I’m very happy that the individual from the Rohinga camp has not succumbed to Covid and is on the mend.
As to my guess…
Listening to Dr Griffin’s description including working next to a fast-flowing river and the father’s poor eyesight made me think of River Blindness.
Looking through the WHO website on Onchocerciasis I get:
Onchocerciasis – or “river blindness” – is a parasitic disease caused by the filarial worm Onchocerca volvulus transmitted by repeated bites of infected blackflies (Simulium spp.). These blackflies breed along fast-flowing rivers and streams, close to remote villages located near fertile land where people rely on agriculture — CHECK
Infected people may show symptoms such as severe itching and various skin changes — CHECK
Infected people may also develop eye lesions which can lead to visual impairment and permanent blindness (CHECK).
In most cases, nodules under the skin form around the adult worms. (CHECK)
Onchocerciasis is endemic to Ghana (CHECK)
Also, it says that Population-based treatment with ivermectin (also known as mass drug administration or MDA) is the current core strategy to eliminate onchocerciasis (another clue)
Finally, I couldn’t see the recommended diagnosis on the WHO website but from the CDC it looks that ‘The most common method of diagnosis is the skin snip. A 1 to 2 mg shaving or biopsy of the skin is done to identify larvae, which emerge from the skin snip and can be seen under a microscope when the shaving or biopsy (“skin snip”) is put in physiologic solutions (e.g. normal saline). Typically six snips are taken from different areas of the body. Polymerase chain reaction (PCR) of the skin snip can allow for diagnosis if the larvae are not visualized.’
So everything lines up with my original bias so my guess of Onchocerciasis stands :).
Can’t wait for the next episode.
Thank you so much.
Dear TWiP Team,
It’s 34 degrees F (2 Celsius) and aggressively windy in Philadelphia. It is so windy, in fact, that I was (quite literally) almost blown off a bridge that traverses a large river that bisects this city on my walk home.
A different, fast-flowing river located in Ghana features prominently in this week’s case involving an adolescent young man and his 70-year-old father. The son developed an incredibly itchy rash that involved regions of hypopegmentation and lichenification (darkening and thickening) mostly in his right lower extremity. His father has a 2-3cm subcutaneous nodule (evidenced by the inability to move it separately from the skin) on his left knee and a similar nodule in the groin area (maybe a swollen lymph node?) accompanied with a new-onset mypopia (nearsightedness). The community they frequent has received community-directed treatment for the pathogen in question, but they have not benefited from these efforts to control this pathogen as they do not reside in the catchment area where treatment efforts are directed.
Both patients had a skin snip/biopsy that was diagnostic.
This can only be one thing (two, rather, in endosymbiotic relationship):
Onchocerca volvulus a filarial worm that is transmitted by blackflies and Wolbachia a bacterial species that I remember hearing about a few episodes back on TWiP. The skin snips were probably dropped in water and small microfilariae came swimming out. I believe even the microfilariae are visible to the naked eye. Though people often develop hyperopia (nearsightedness) as they age due to hardening of the lens, new myopia is not a disease of age. The father’s myopia presenting in his 70s is pathognomonic for “river blindness” caused by the massive human inflammatory response when Wolbachia is released from dying onchocerca adults in the eyes. I would treat both the father and the son with doxycycline for two months (for the Wolbachia) and ivermectin once a month for several months, maybe even an entire year (for the Onchocerca). I’d start the doxycycline prior to the ivermectin. I’d want to check hepatic function for both of them prior to starting ivermectin. I don’t actually know how often to dose Ivermectin but I’d want to move gingerly with killing off onchocerca because I believe killing them too quickly can cause a massive inflammatory response that could lead to distributive shock and even death. I’d provide the son with diphenhydramine cream to relieve the itch because itching can be so awful!
For the long-term, is there a way to include the two of them in the local onchocerca control programme, which probably also involves treating with ivermectin?
Thank you so much for yet another incredibly educational and thrilling episode!!
p.s. My significant other who finds parasites too disturbing to listen to TWiP episodes with me commented that “the look of sheer joy” on my face “must mean there is a new TWiP podcast.” A very good diagnostician.
To quote the case description: “I went to this small village, we’re in
Ghana, just a couple of weeks ago, and this village is right by this
really fast-flowing river -” *buzzing sound* Onchocerca volvulus! NEXT!
All the best,
Alexander from Vienna, Austria
Hello Twip team!
I recently discovered your podcast and could not be happier! Thanks for all your great work! I am a second year resident of infectious diseases at Helsingborg hospital in Sweden. My residency so far has completely revolved around covid and I’m grateful to get to learn more about other infectious diseases from all of you.
My guess for this case study is onchocerciasis or river blindness caused by the nematode Onchocerca volvulus. The fact that the father developed visual impairment and nodules under the skin after farming close to a fast flowing river made me consider this as the most likely diagnosis. The blackfly, the vector of disease, breeds in fast flowing streams.
The adult worms give rise to nodules under the skin, usually around the shoulder and hips. The tissues around these nodules can secondarily lose their elasticity
and especially in the groin, so-called “hanging groins” can develop over time. Let’s hope it doesn’t come to that!
Thanks for yet another great episode!
Best wishes from a sunny but cold Malmö!
Greetings from Salt Lake City! I am a post-doc studying infectious disease at the University of Utah. Due to a long-standing fascination with parasites (that really started when as an undergrad I became amazed by the life cycle of Strongyloides), I have taken much enjoyment from the TWIP podcast but have never submitted a guess.
In regards to the father and son reported on episode 203, I think these two are suffering from Onchocerciasis, caused by Onchocera volvulus. My guess was based initially upon hearing that the father had some vision issues and the two lived near a fast moving stream in a rural area. Onchocerciasis is also referred to as river blindness, due to the potential vision changes from infection, and its association with fast moving streams where the vector, the Simulian Black Fly, breeds. The CDC’s website reports that this disease often presents with nodules under the skin, and an itchy rash that takes on a “leopard skin” appearance, which are similar symptoms to what was reported. Diagnosis can be achieved via biopsy, as was performed on these individuals.
Thanks for the great podcast,
Greetings TWiP team,
I write from Southwestern Ontario, Canada, where it is overcast, minus 4 celsius (25 fahrenheit), and with negligible wind.
Emboldened by a correct diagnosis of the tripartite case in episode 202, I am hazarding another guess. I do so confidently this time however, since I feel the case presented in episode 203 can only be one thing!
The Ghanian farmer in his seventies and his teenage son, are the unfortunate recipients of a filarial worm infection. The frequent mention of visits to the river seems almost a red herring, until the life cycle of the worm’s black fly vector (Simulium species) is considered. The mention of the river also provides a tantalizing link to the common name of this disease, River Blindness.
The filarial worm in question is Onchocerca volvulus, which presents rather differently than other filarial worms.
Between the man and his son all the manifestations of Onchocerciasis appear to be present except for lymphadenopathy and nodding syndrome. Those present manifestations include:
Onchodermatitis (itch and discoloration of the legs on the teenage son)
Nodules (firm nodules around a few centimeters on the father)
Ocular Lesions (presumed as being responsible the failing eyesight of the father)
This last manifestation gives us the common name for the disease.
The positive skin snip described in this case is a common way to diagnose Onchocerciasis, and I further understand a skin snip was the means of its discovery (doesn’t skin snip just roll off the tongue).
Treatment for both will involve long term administration of Ivermectin to target the microfilaria, potentially preceded by Doxycycline targeting the Wolbachia endosymbiont responsible for the actual pathology. However, it is critical to account for concurrent infections that might complicate treatment, especially a concurrent Loa loa infection – the consequences of not doing so can be severe.
A question for Dr. Griffin: Because of the distance of the father’s nodules from his head and eyes, would it still be prudent to surgically remove them as part of treatment?
Thank you again TWiP team for your wonderful work!
Thank you for all the time and effort you put into your podcasts. I’ve been listening for almost two years now so it’s about time I diagnose a case. I’m only a carpenter/cabinet maker but I’m confident I know this one.
I believe the father and son are hosting onchocerca volvulus. The fast flowing river where the two spend most of their time is an ideal environment for blackfly larvae. Blackflies have had plenty of opportunities to pass along onchocerca microfilariae which made their way to the father’s knee and groin. Skin snips of the nodules would have shown motile microfilariae, confirming the diagnosis.
1. LJ is lowenstein Jensen media.(https://en.m.wikipedia.org/wiki/Löwenstein–Jensen_medium)
2. You mentioned a rapid flowing river, possible visual concerns and biannual community treatment which all lead me to think of onchocerciasis immediately. The symbolism of an older father with a teen son also reminds me of the attached statue which strengthens the link. Maybe I’m biased though (https://medstudentstories.merckmanuals.com/on-the-wings-and-mouths-of-black-flies/) Already have a book but was just excited about the case.
Dr. Adil Menon
Hallo twip team
Greetings from a grey Braunschweig, Germany. It is 2C, 37F, waiting for spring.
After having guessed right a few times by now, I thought to give it an official go.
My guess is onchocerciasis as it is controlled with a biannual dose of ivermectin,has a connection to a river, bumps under the skin and a leopard skin appearance according to Wiki.
Thanks for all twiv keeping me sane and my mind working while working as a cleaning lady.
They both have Onchocerciasis also known as African river blindness.
(I haven’t won a book yet so please include me in the drawing).
Love the show,
Renee from Seattle
I’m sending in a guess for TWiP #203 on behalf of the 2nd year medical students in the Global Health Track at Western University of Health Sciences in Oregon.
We think these patients are presenting with Onchocerca volvulus. The river exposure, location in the world, the son’s severe itchy rash and skin pigmentation changes, and the father’s nodules and vision problems are all indicative of Onchocerca volvulus. In addition, the typical diagnostic test for this bug is a skin snip. Regular Ivermectin distribution in this community in Ghana has likely protected many of the people who live there, but, like you mentioned, this dad and son are not residents of the community near the river that is provided this medication, which is typically given every 6 months.
We look forward to listening to the next podcast!
Madeleine Duncan, OMS II
Western University of Health Sciences
College of Osteopathic Medicine of the Pacific Northwest
Kia ora from Pongaroa,
My guess for the father – son case in Ghana is Onchoceriasis. Swimming in flowing water, the characteristic ‘leopard skin’, and itching point to it. I will not go into details because I am going to sit back and enjoy all the wonderful answers like we got in TWiP 202. It was like the legendary Kevin was back… well almost.
The only comment I will make is how silly it is to only treat or give preventative measures for endemic diseases to a certain demographic. In New Zealand someone was asked to prove their residency before getting a Covid-19 vaccine. The government made it very clear that everyone in the country had the right to get vaccinated at no cost – even those illegally in the country.
Today it is 10 degrees C but definitely feels colder. The rain has started and will continue to shower for the rest of the week by the looks of it. Now to address the two villagers from Ghana. Based on the findings I’m afraid both have contracted the filarial nematode Onchocerca volvulus. The good thing is it was diagnosed early, as they both still have functional vision. The black fly serves as the vector for the small stage of the worm. These flies require fast-moving oxygenated water to reproduce. Thus swimming in and living near a fast-moving river would put them both at risk of exposure. In order for the worm to enter the skin, it must first crawl out of the fly’s mouthparts and then enter the bite opening after the fly has left. All of this must be done fast and without being swatted or shaken off, talk about agile! The nodules on the father correspond to the bite sites as Onchocerca tends to stay put after entering the bite opening. These round nodules form from coiled adult worms and their size depends on the number of worms and how large they have grown. And my goodness can they grow, up to 3 ft! Sexual reproduction produces millions of microfilaria that migrate away from the nodule. This causes skin irritation, itching and a change in colour. Connections exist between the subcutaneous tissue and the eyes, and if enough microfilaria find their way blindness can occur. The nodules on the farmer are quite far from his head thus it may take some time before the microfilaria reach his eyes. For this reason, I’m not sure if his vision is fading due to the worms or are from naturally occurring cataracts. Looking at a skin snip close to the nodule or the nodule itself will provide a diagnosis. Treat both with Ivermectin and resect the nodules.
Daniel from BC, Canada
Dear TWIP Tetrad,
Greetings from Creighton University in Omaha, Nebraska where it’s a mild 50 degrees Fahrenheit with partly cloudy skies.
In celebration of Pi Day, I asked my class to answer your latest Case Study with the promise of 3.14 extra credit points. Even though we did not yet cover this parasite in class or in the lab, the students reached an overwhelming consensus with their answer:
One possibility is Trypanosoma brucei. Although both father and son did not experience fever or headaches, T. brucei can cause skin rashes and swollen lymph nodes, the former of which may account for the son’s discolored leg and the latter accounting for the father’s nodules. This parasite can be tested for by a blood test. However, it’s likely not T. brucei because of the lack of other symptoms, like visual impairment, and the Tsetse fly’s habitat of woodlands. It is likely Onchocerca volvulus, which causes Onchocerciasis (“river blindness”). Symptoms include severe itching, visual impairment, and nodules under skin. It’s also endemic to Ghana. Both infected people were near a fast running stream before infection. Blackflies, which vector O. volvulus, breed in fast running streams. Both infected people experienced skin disfigurements consistent with O. volvulus infection. Finally, both infected people experienced itching. To treat, administer Ivermectin in 6 month increments until symptoms subside.
The second case sounds like what people call river blindness. Onchocerciasis? You mentioned the water was fast running in the area, which is what the vector likes. I think it’s called colloquially a black fly? It puts a parasite in people that causes both blindness and skin bumps and itching Which can be severe. The father, I think, although he claims good vision says that it’s only good if he’s close to the subject. It also mentioned that the father and son only work or visit the region and thus , unfortunately, aren’t getting the preventative treatment. A truly good old fashioned and well documented use for Ivermectin, if I remember correctly.
Keep up the good work, if you please. We will listen 👍
I was too slow with the last case guess! Hope this makes it in time!
I think both these patients have onchocerciasis, which causes a horrible dermatitis as well as skin nodules, and diagnosis is made by skin snips.
All the best,
I am writing from snowy Fargo North Dakota where it’s -1 Celsius degree. As a long time listener it’s my pleasure to take part today .
As a newcomer to United States and being fifth year medical student back home (Hargeisa Somaliland ) I would love to get your advice on where to start especially medical school in here where I am also told it’s very expensive to study medicine in here, but in my heart I can’t see doing nothing else except studying medicine ,so I would really appreciate your advice very much . I think it was just only yesterday watching Vincent explain microbiology on Lecturio on my second year of medicine and by the way I really appreciate doctor Danial Griffin coming to Africa and sharing his knowledge and helping poor African nations.
River blindness is the disease that young boy and his dad suffer. River blindness is a disease spread by black flies which tend to live near fast running rivers or in streams here in America there are programs to control it but still it affects 1000 people per year in America but that is small number compering to some other countries. The good news is that countries could be free from it as in the case of Colombia , Mexico, Ecuador , Guatemala which all were declared to be from the disease .
O. volvulus may bite a person and deposit the parasitic worm larvae onto their skin. These larvae can then enter the skin through the bite wounds.
River blindness causes skin and eye problems
Skin rash appears as an itchy rash that resembles eczema in which there is small pus filled like blisters or a itchy raised dark patches on the hands or feet as in the case of our two patients described by the doctor .
The patient had lumps beneath the skin which measure up to several centimetres and that is where adult worms lives and grows it’s hard to kill those in the lump as they are adult female and male the ivermectin will not kill them.
The way that river blindness hurts the eyes is that it dies inside the eyes and then causes inflammation which in return causes a raise in pressure which hurts the nerve.
Swollen lymph nodes could be seen as symptom too.
Treatment for onchocerciasis is with (ivermectin) for 10-15 years which just kills worm larvae but not the adult form.
Antibiotics such as (doxycycline) are also used to kill the bacteria which the parasite feeds upon.
Dear TWIP professors
Greetings from Parasitology Club at University of Central Lancashire in the beautiful northwest of England.
We would like to add our considered opinion for the case of a father in his 70s and teenaged child who reside in a small village in Ghana in sub-Saharan Africa. The boy developed a severe itchy rash in his right leg with light and dark areas while the father has nodules in his groin area and left knee. The father experiences some visual issues. They both have a diagnostic skin snip. The risk factors include a fast-flowing river, in which they both swim and the father farms near the river.
The most probable cause of the condition is the parasitic worm- Onchocerca volvulus which causes onchocerciasis, also known as river blindness. It is a tropical disease transmitted through repeated bites by Simuliidae (blackflies). Blackflies breed near fast flowing rivers near rural villages. According to Murdoch (2020) the main burden of the disease is found in countries in sub-Saharan Africa. The disease can cause visual impairment due to inflammation of the optic nerve, intense itching, nodules, and rashes. Most symptoms are caused in response to dead or dying larvae.
The blackfly introduces third stage filarial larvae through bite wounds. The larvae mature into an adult in nodules of subcutaneous tissue. The female worms are capable of producing microfilariae in subcutaneous nodules for 10-15 years. They have a lifespan of 10-15 months. They are typically found in skin and lymphatics of connective tissue. They are sometimes found in peripheral blood, sputum, and urine. Microfilariae are ingested by blackfly when biting an infected animal and migrate from midgut through haemocoel into thoracic muscles where they develop into third stage larvae. They can migrate into proboscis and affect an individual.
The diagnosis can be performed by skin snip, which is examined by light microscope. Larvae emerge from the skin snip. PCR (Polymerase Chain Reaction) enables diagnosis if larvae are not visible. Nodules can be removed surgically and examined for the adult worms. Slit-lamp examination of anterior part of eye where larvae are visible can be useful in cases of visual impairment. The recommended treatment is ivermectin which only kills the larvae, and not the adults (WHO, 2019). It is administered every six months if the evidence of infection persists. Doxycycline can be used to kill adult worms by killing Wolbachia bacteria on which adult worms thrive. Wolbachia has symbiotic relationship with many arthropods. A combination of both can be advised in some cases.
Thank you for another challenging case.
On behalf of the Parasitology Club of the University of Central Lancashire.
Centre of Diseases and Prevention. 2019. Parasites-Onchocerciasis (also known as River Blindness) [online]. Available from https://www.cdc.gov/parasites/onchocerciasis/index.html. [Accessed 08th March 2022]
Murdoch, M.E. (2020). Mapping the burden of onchocercal skin disease. British Journal of Dermatology. Available from https://onlinelibrary.wiley.com/doi/10.1111/bjd.19143.
[Accessed 10th March 2022]
World Health Organization: WHO (2019). Onchocerciasis. [online] Who.int. Available at: https://www.who.int/en/news-room/fact-sheets/detail/onchocerciasis.
I enjoy listening to TWiP while doing work around the house. Of course, I have to pause to jot down the clues to the mystery case. This month I had to rewind to get them all.
This is the case of a father and son who farm near a fast flowing river. They do not live in the local community so have missed out on the twice yearly mass drug initiative. The son has a severe itchy rash with skin discoloration on the right leg. The father has firm fixed nodules on the knee and groin. He also seems to have decreased visual acuity. Diagnosis is made by skin snips.
It seems Dr. Griffin has given as many clues as possible. I’m guessing the parasite is Onchocerca volvulus.
I’m keeping this short as I expect you will get many responses this month.
Best wishes to you all
A fast running river in Ghana immediately brings to mind black flies,. So let’s run through the symptoms noted:
1. Itchy Rash (dermatitis)
2. Changes in skin colour (especially on the right leg)
Father (in 70s):
1. 2-3cm nodule on knee, nodule in groin area
2. Poor vision
Diagnostics through skin snip. In the village near the river there is a mass drug administration programme underway (MDA). This MDA programme involves giving something twice a year.
As they say, when hearing hoofbeats, think zebras, not horses (if you are on the Serengeti). All of the symptoms here point towards river blindness caused by the filarial nematode Onchocerca volvulus. The diagnostic skin snip also fits this picture. Despite the efforts of the African Programme for Onchocerciasis Control (APOC – 1995-2015) and the follow-up WHO Expanded Special Programme for the Elimination of Neglected Tropical Diseases (ESPEN), onchocerciasis remains highly prevalent in many districts of Ghana . This is in part due to exactly what was noted in this case: “failure to recognize important foci of active transmission adjacent to areas under treatment” . So that’s my guess: river blindness. The treatment for this is twice-year doses of ivermectin for at least 10-12 years (the lifespan of the adult worms that are not killed by ivermectin). The arduousness of this treatment regime emphasizes the need for more effective drugs and (one can dream) a vaccine!
Writing from cloudy Cape Town (26°C / 78°F and windy),
P.S. thank you for the opportunity to think about something besides SARS-CoV-2.
1. Otabil et al, “Prevalence of onchocerciasis and associated clinical manifestations in selected hypoendemic communities in Ghana following long-term administration of ivermectin” – BMC Infectious Diseases 2019 – doi:10.1186/s12879-019-4076-2
2. African Programme for Oncocerchiasis Control, “The WHO African Programme for Onchocerciasis Control Final Evaluation Report” – WHO, 2015: https://www.who.int/about/evaluation/jaf21-apoc-final-report15-v5.pdf
Hello TWIP team!
I recently started a new job as an HIV epidemiologist for an unnamed state health department. We all work remotely, so for team-bonding, I suggested we try each month’s TWIP Case study!
So here is our combined entry:
We think the fishermen father/son duo have River Blindness (Onchocerciasis). Thanks for the nice clue of the eye-sight struggles and the nearby river. We appreciate this soft-ball to get our group started.
Onchocerciasis is caused by the nematode Onchocerca volvulus – an infection that is endemic in Ghana. River blindness is transmitted by the blackfly that lives and breeds near fast-flowing streams and rivers. We were stunned by an image of andb5dd589-6493-4730-be9f-b5c5573783c0.jpg
Onchocerca parasite emerging like a little worm harpoon from the antenna of the blackfly! Evidently, this parasite isn’t nice to its fly host either.
Symptoms of River Blindness include rash, itching, bumps, cataracts and nodules under the skin. The nodules contain the adult worms. It can cause blindness and is the second most common infectious cause of blindness after trachoma.
Treatment for onchocerciasis is ivermectin, which kills the larvae, however ivermectin does not kill the adult worms. To kill adult worms, doxycycline, an antibiotic, can be prescribed which kills (Wolbachia) bacteria INSIDE the adult worms that they depend on to survive. So cool! A caveat to treatment with ivermectin is that patients must first be tested for co-infection of another parasitic infection called Loa loa. If someone also has Loa Loa, ivermectin can cause serious brain swelling that can lead to coma. From what we could gather, the theory is that ivermectin kills so many microfilaria – many of which are near the eyes and brain – and this mass die off causes encephalopathy and/or hemorrhage of the eyes. This complication of co-infection has greatly impaired Mass Drug Administration programs of ivermectin in areas where river blindness is endemic, and now requires a test-to-treat approach.
It’s always a good idea to think of other causes as not all disease presentations are typical, and symptoms can coincide from different causes. For this one, Shisto is a possible cause, but it’s uncommon in the flowing water, and the ‘disturbed vision’ complaint.
Thanks for the interesting case study and opportunity to chat with colleagues about diseases!