Case guesses

Michael writes:

Hello gentlemen,

After listening to Dickson becoming highly suspicious of the fact that the husband did not have any bites (and I listened to this over and over many times even at 1/2 speed), I am convinced that said husband would get up in the middle of the night and scrape mite ladened pigeon poop off the window sill and sprinkle it on the exposed midriffs of the unsuspecting victims as they slept. Or maybe the women were leaning out over the encrusted window sill and waving to the neighbors during the day while still wearing their pajamas.

WAIT! Isn’t NYC the bedbug capital of the world!!!   Naw, that would be too easy. I’m sticking with the pigeon mites.

Mike in Oregon

Jan writes:


After a brief break from sending in guesses, I thought to give this one a try; bedbugs. Itchy red small welts in a regular pattern after waking up, and living in the New York metropolitan area ? Are there any other candidates ? As for the husband not showing any symptoms, Dickson’s suggestion of separate bedrooms makes sense especially if his bedroom is a way off from the others ( i.e. a really loud snorer )

Greetings from overcast, drizzly Rotterdam, temperature 16 C

Tubby writes:

Greetings TWiP Trio,

I usually don’t venture any actual diagnosis for your cases because while I find listening about parasites to be interesting I find the reality of them to be horrifying.  So I decide every episode that it’s malaria and sometimes I’m even right.  This time though it sounds like a case of not so squicky bed bugs, Cimex lectularius. Ectoparasites are parasites too! That the husband is unaffected is interesting and I look forward to hearing why that might be.  It would be nice to know if the younger daughter had a sleep over at a friend’s house or she stayed overnight in a hotel in Manhattan shortly before the symptoms appeared at home.  While living in NYC I was advised to keep my mattress in a waterproof vinyl bag so that I might not have to replace it if I moved into an apartment where they were already present or if I brought them home from a movie theater.

Kind regards,


Dr. Wink writes:

Dear Professors,

I am getting so many TWIP cases wrong that I have sadly concluded that I have the wrong skill set. This week I asked my wife for guidance. Lynn is an artist and a designer and she thinks the ladies are being bit by mites. She wants a skin biopsy.

Wink Weinberg

Dave writes:

Dear TWiP Trio,

After 2 weeks of not e-mailing diagnoses (and extremely baffled by the case of the penguin), I finally feel confident enough in this week’s case study to venture a guess. I will say that the 3 afflicted family members were dined upon by bedbugs in New York (the 13 year old daughter) and Europe (the mother and older daughter).

The reasons for this guess are because as the shownotes mentioned, New York is an epicenter for this problem, and everyone knows bedbugs are not uncommon in the NY metropolitan area. They are, however, also common in many European countries, ans the fact that almost every member of the family was afflicted is merely coincidence.

Bedbugs tend to gravitate to warm areas on the body (ie the trunk) and their bites appear in line form as itchy raised rashes.

When I last emailed, I had mentioned my acceptance into a PhD program at the Tufts Vet school, and you inquired as to the name of the PI – I will be working under Dr. Patrick Skelly studying schistosome tegument proteins and host-parasite interaction.

Thank you once again for the informative podcasts,


Dave P.

Elise writes:

Dear TWIP Trifecta

I hope this finds you well. I also dearly hope you don’t get any pushback from listeners about the misleading aspects of last week’s case study. I would never mind hearing about any non-human cases, and was happy to hear about the penguin patient. It was such a tremendous pleasure to hear Paul Calle’s case study and hear about his work at the Bronx Zoo (which I love visiting and am hoping to be there over Memorial Day weekend). I also loved the video this week not only for getting to see all of you but also for getting to see the patient’s environment. Since I truly have no background in the sciences, there was no way I was going to be able to diagnose TWIP 109 correctly, and I didn’t send in my guess (which actually was probably going to be Babesia except I wasn’t quite satisfied with the way all the symptoms presented in the timeline, and then I couldn’t find another likely solution.  Thank you so much for having Paul on TWIP.

I am not at all certain about my diagnosis for the three women in the Greater New York Metropolitan area but I suspect that the relapsing patterns of red lesions have been caused by bed bugs. Perhaps because I am in Lower Manhattan and in the city, where bed bug stories are legion, I am not quite convinced that I’m correct because it seems a little too obvious.

The clues that make me think bedbugs are the culprit are very basic:

– The three patients contracted these relapsing lesions consecutively (not all at once— which suggests that the parasite started in the 13 year old’s bed and found a way to migrate into the two other beds).

– As Dr. Despommier pointed out, the lesions show up in the morning, after not having been present the night before.

– The pattern of lesions fits the bedbug profile of taking meals in a row (“breakfast, lunch, dinner, snack”)

– The patients have no other symptoms beyond the rows of itchy red bumps, which is standard for bed bug bite sufferers who don’t have a pronounced allergy.

– No one experienced symptoms of any kind while the family was on vacation and then the lesions began reappearing after everyone got home (where the bed bugs, if I am correct, were house sitting for them).

As to how the bedbugs could have made it into the house, there are countless possibilities. They could have hitched a ride in the gym or gear bags of the daughters, particularly if they are in the trunk of cars with a lot of other kids’ bags from a lot of other houses. If one of the daughters spent the night at a friend’s house or took a school trip and stayed in a hotel, the bed bugs could have come home with her.

There is one family member who has not yet developed any kind of lesions. I wonder if he has simply not noticed that he has been bitten. (Some people are not sensitive and require a greater number of exposures over a longer period of time to start reacting.) Another possibility is that his wife is more appealing to bed bugs. I am one of those people who gets bitten by mosquitoes when no one else around me gets bitten, so perhaps it is possible for something similar to be happening

I actually somewhat hope I am mistaken in this diagnosis because getting rid of bed bugs is a huge pain.

Thank you so much again for the wonderful case of the unnamed penguin. I’m glad he recovered.

And thank you so much for TWIP. It is a pleasure.

Best wishes

Brendan writes:

Sounds like bedbugs.



Gregory writes:

Hello fellow TWiPers!

I am a recent undergrad graduate  from Saint Joseph’s University. Regarding the case study this week, the signs of this parasite sound familiar to a common college dorm infection: scabies. My thoughts are that the red lesions (particularly around the waistline and legs) are in dark places and folds of skin, common locations for scabies rashes. This explains why it would spread from the daughters to the mother; however, I am not sure as to why the father has not contracted the lesions.

As for why the rash subsided when they traveled, my guess is that once they traveled away from the home (and, subsequently, their sheets, beds, couches, etc.) the scabies were no longer in continuous contact.

Thank you for your consideration. I am a new listener to TWiP and I listen to the whole family of podcasts. I thank you all for your hard work and I hope to learn more from continuous listening.



Don writes:

Dear Twipers,

After last week’s curve ball involving a non human host, it looks like you decided to pitch this one straight down the middle.   So after taking no notes or doing any research I am swinging for the fence and submitting Cimex lectularius as the culprit. (All this assumes that you did not become even more diabolical this week.)

I will note that I have read many accounts of New York bedbugs in the past few years.  That I have observed that many times the bites are linear.  And that the husband not being symptomatic only indicates that he is one of the significantly large percentage of people who do not react to being bitten.

Never miss ANY of the episodes of ANY of Dr. Racaniello’s podcasts.  An impressive body of work!  Thank you all.

It is perfect Greenville, South Carolina  weather.  Currently 17 C without a cloud in the sky and a promise of warming to 28 C later.

Life is good,


Jeff writes:

Hello TWIP triumvirate,

I didn’t hazard a guess last time as I couldn’t come up with a parasite which would result in pulmonary edema in a four-year-old with a history of raw fish consumption.  Now I know why!

This week’s case is likely due to bedbugs.  A little known fact about these pests is that not everyone will have a reaction to the bite.  It is likely the husband was bitten as well, but just didn’t have the reaction that the wife and daughter’s exhibited.


Jeff Fairman, Ph.D.

Vice President, Research

SutroVax, Inc.

South San Francisco, CA 94080

Jen writes:

Hi TWIP team,

Thanks for covering avian malaria, what a tricky case.

Relevant to your last episode, I was saddened to hear about this recent report of loon malaria:

It appears parasites were also found in the brain of this bird – so could it have been acting more “loony” than usual?

More seriously, what are your thoughts on this? Could an average bird watcher/enthusiast notice a behavioral difference in an infected wild bird? And do you think this is an isolated case or potential epidemic?

My guess for the current case is bed bugs.



Heather writes:

Hello TWiP,

I think the ladies with the bites have a bed bug infestation, possibly acquired by bringing home soccer uniforms or drama costumes that were in an infested home. For treatment I suggest they burn their home to the ground, with all of their possessions inside, and start afresh far far away from NYC.

As for why the husband is not reporting bites: what, if anything, do all four family members wear while sleeping? This choice may be facilitating bites on the women. Or is the husband perhaps very hirsute? This may be TMI, but since I stopped shaving my legs I experience fewer mosquito bites. I’m not that hairy but I think either the hair dissuades the mosquitoes from landing or I feel them more quickly and swat them.

I know two vets who have interesting elasmobranch parasite case studies. One involves a professional sports team. I will pass along their emails if you want to try to recruit them to TWiP.


Corey writes:


This weeks case sounds like the classic symptoms of bed bugs.  There is no need for a differential diagnosis.  This is the “breakfast, lunch and dinner”, which is often a euphemism for the set of linear bites associated with bed bugs.  It is odd that the husband doesn’t have any of the bites on himself but they probably prefer the odor of the others in the house.  I know my wife will attract mosquitos more than I will at times, perhaps bed bugs are similar in their host homing behaviors.

You may want to update the description of TWIP on your web page, it still says, Dick Despommier, and I know a while back you mentioned that he prefers to go by Dickson.

All the best,


Chris writes:

I’m writing from Somerville, MA, and spring has finally arrived.  It’s 72 F, the sun has set, and it was a really pleasant day!

When I picked my first case to diagnose a few weeks ago, I initially thought I had an easy one (TWiP 107).  I was proven a bit wrong.  This time, I had an idea of a diagnosis even while listening to the case history.  The location was highlighted as important, and I know bed bugs are an issue in NY.  It sounds like these skin irritations were appearing during sleep, so that’s another check mark for bed bugs.  The CDC fact page on them even mentions the bites can appear in a line.  It’s possible the husband is getting bitten, too, but his skin doesn’t react.  That’s what I’m going with – bed bugs!

I wish you all a good holiday weekend!

Chris from Massachusetts

Mark writes:

Hello Twip Trio;

There is a definite source of infection.  It could be the bedroom, but it could also be outside a window.

Scabies would be consistent with the lined up linear series of bites. However they would also be in the intertrigenous areas such as the webbings of the fingers.  They wouldn’t go away during  a trip to Europe.

Bed bugs would be a very generalized series of bites that wouldn’t be restricted.  They occur in lines in clusters in unclothed regions and are not limited to one area such as the waist, which is probably clothed.

Fleas don’t leave linear patterns but clusters. They would bite where clothing is loose such as waist but also the legs.

I am very stumped but a guess would be bird mites.  It is a nocturnal feeder and can bite where the clothing fits tightly, such as where elastic bands are located, though it can be generalized to other areas.

Don’t know, but look forward to the answer.

29 degrees C in Oklahoma today and humid.

Mark writes:

Hello Team DDV,

First, I want to congratulate you all and say “well played” with the subterfuge in TWiP 109’s case discussion of the “four year old female”. The reveal in episode 110 by, Dr. Paul Calle, that the patient was a four year old penguin was masterful. A shocking reminder that TWiP was conceived to cover eukaryotic parasites, not just those of us Homo sapiens.

I am making an educated guess of what the parasite for TWIP 110 is. There are not enough facts to support a good differential diagnosis. I nominate common bedbugs, Cimex lectularius, as the parasite for this show. Here are my reasons:

  1. Waking in the morning and discovering 3-4 small, red, colinear and potentially itchy sores is consistent with being bitten by a bedbug. See this note at the CDC’s website:
  1. The mother has been described as being a frequent traveler. Bedbugs infest hotels throughout the world. Bedbugs are commonly spread by hiding in the seams of luggage. Her frequent travel provides an opportunity for contamination.
  1. The mother and two daughters are described as very active in youth soccer and bringing other girls into the game. This also is another potential source for contamination.
  1. Daniel describes the family having a “recent” trip to New York, implying Manhattan. He was silent on if it was a day trip, or overnight travel. Why is this important? Manhattan hotels have, in recent years, problems with bedbug outbreaks. Search Google or for more information. If they stayed at a hotel then its another source for contamination. OR, if they check bags, or clothes, at a theater or restaurant there is another potential source for transmitting bedbugs back to their home.

The metadata that Daniel communicated is equally important to me than the scarce clinical facts. He commented that the colinear wounds are — I forget the exact word — either “typical” or “classic” for this parasite. Later he commented that N.Y. is the “epicenter” for this show’s case. Responding to questions from Vincent and/or Dickson about inspecting the home bed sheets Daniel avoided answering the question. I seem to recall this is when he introduced the image of “Dr. House” sending his staff to break into problematic cases homes in search of environmental information affecting diagnosis.

Too bad Vincent or Dickson didn’t vigorously pursue their question. The CDC note indicates, finding bedbug stool, shed outer skin, or blood stains from the bites is important to diagnosis.


Eric writes:

Dear TWiP triumvirate, thank you for another fun case of the week! My guess is as follows:

The mother and daughter are all quite gregarious

Yet the father, unaffected, suspects the nefarious

Why do the ladies get bumps from their beds?

All over their bodies, but not on their heads?

He sleeps on the couch, suspecting Cimex lectularius

Seattle is enjoying sunny and 26 C, a true delight in May.



AJ writes:

Hello twip team!

I thought I’d take a break from my post bacc applications to catch up on my podcasts, and to my delight there is a case I think I actually know!

I’m writing in about the case where the humans have “bug bites”. I put those in quotes because it seems people blame bug and spider bites for a wide variety of skin conditions. However, I’m pretty sure these are bug bites!

Sadly, I recognized this condition almost instantly. Itchy bumps, in a row of three or four, appearing in the morning, spells bed bugs. The pattern of three bumps is often referred to as ‘breakfast, lunch, and dinner’. This scourge is in San Diego, and I am unfortunately intimately aware of it. To clinch the diagnosis, yell at the patient, break into their house, and check the mattresses, according to House MD.

Dixon seemed to be surprised that the male didn’t have bumps, but most people don’t actually get itchy bumps, so that isn’t so surprising. I didn’t even realized I had bed bugs until I saw one. If you can’t find the bugs, look for their fecal stains along the seams of the mattress, like someone dotted it with a sharper.

Fleas would be my second pick for ectoparasites, because of the linear bite patterns. I don’t know so much about other dermal conditions… although it possibly could be cutaneous larva migrans, but that doesn’t fit so well especially with the travel history.

If it is bed bugs, I am very very sorry, as they are extremely difficult to be rid of. Of course, the damage is greater psychologically than physically.

Thanks for the inspiring podcast as always!


Parasitologist Wannabe,

San Diego

Where June gloom is thankfully kicking in.

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