Carol writes:

Greetings Team TWIP,

While I listen to every episode, it’s usually when I’m in my car and by the time I would be able to email a guess for the case study, I’ve moved on to other items on my to do list and the email never gets written. Today I happened to listen to the end of the episode at home and am emailing right away. 

My guess for the 2 volunteers with frequent diarrhea is infection with cryptosporidium. My guess is based mainly on the list of food they didn’t eat (all infamous for being true source of crypto outbreaks). My other possible choice would be giardiasis because I know there can be intolerance to dairy post-infection, but I’m ruling it out because Dixon has drilled “Giardia causes steatorrhea” into my head. A quick google search says that secondary lactose intolerance can develop wth crypto so I’m sticking with my initial guess. 

Hope I’m right, but even if I’m not I at least have a chance to win a book! 

From a sunny day in Victoria BC (the first one after 3 straight weeks of rain),

Carol

Courtney writes:

Dear Doctors, 

Hello from Omaha, Nebraska where we are currently experiencing a period of warm weather.  Hopefully we do not see a repeat of last year’s severe flooding. 

First and foremost, the guess for episode 180.  My guess is Cyclospora cayetanensis, based on the two symptoms of loss of appetite and diarrhea.  This organism is located primarily to the tropics/subtropics and is linked to unwashed plants (such as raspberries, basil, salad mixes, etc). The timeline fits as well (1-2 weeks for onset of symptoms). 

Another possibility is Blastocystis homini, but it seems this organism usually infects patients that are immunocompromised. 

Secondly, in episode 178 Dr. Despommier mentions there are no lions in Asia. There is a small population of lions that live in India, usually referred to as Asiatic lions https://en.wikipedia.org/wiki/Asiatic_lion

Stay curious, 

Courtney

— 

Courtney Burson

Graduate Teaching Assistant

Department of Biology 

University of Nebraska- Omaha

Andrew writes:

Kia ora from Pongaroa

Book not won. Don’t care – the fun of working on a solution is my primary motivation. I keep telling myself that.

The weather here is hot 28°C and parched. The whole of the North Island and the top half of the South Island are basically in drought. The bottom of the South Island is being flooded. Climate change is here and it is nasty.

I was one of the many who got caught out last week by the clear malaria test. Lesson learned – false negatives as well as positives exist in the real world and need to be taken into account.

The case of the two young women with tummy trouble that was cleared up after treatment with trimethoprim/sulfamethoxzole. This is what we programmers call reverse-engineering.

That treatment works for a wide range of conditions but only a few are parasitic so I am going to plump for Cyclospora cayetanensis. Parasitic Diseases Lectures #18: Protozoans of Minor Medical Importance (As Dixon notes in the opening comments – minor unless you get have it). The symptoms fit as does the treatment.

The cramps after milky coffee is puzzling. I assumed there might be some lactose intolerance in the wake of the treatment as the balance of the intestinal flora and fauna could have been disturbed. But I cannot find anything online that would confirm this. So I will put it down to vengeance being taken by the great goddess Kaffenia, who is upset at 

mortals desecrating her great gift to humanity with milk.

Nā mihi

Andrew

Amanda writes:

Hello! I am so excited to get my copy of PD 7 and it will sit proudly on my shelf when not being read. I do hope it will be signed by the whole trio of parasite professors! 

On to the case of water(fall)-y diarrhea… there is no shortage of parasites that wiggle to mind when presented with profuse, watery diarrhea. However, I believe these two travelers encountered cyclospora cayatenensis. The frequency and consistency of diarrhea fit the symptoms of cyclospora. When the picnic by the waterfall was mentioned I originally thought of Giardia, but then the treatment would have been some form of Flagyl and since they were given trimethoprim/sulfamethoxzole, I kept searching the list of likely suspects. Since their gastrointestinal tract has gone through a thorough evacuation, it has not had to replenish the good samaritans that allow us to enjoy foods containing diary products and that is why one seemed to relapse upon ingesting some dairy shortly after her illness. A bland diet and slowly easing back in to regular fare is the smart way to go.

I must cut my email refreshingly short this week, but I greatly appreciate all that you do and I eagerly await the arrival of my prize. 

Thank you again, 

Mandi Letzkus

P.S.-I had an idea for a new merchandise item. A t-shirt with assorted microscopy photos of parasites on the front and on the back “Ya know, it’s interesting…” -Dr. Daniel Griffin

I have recently noticed that whenever Dr. Griffin says this phrase (which is quite often) some fascinating information is soon to follow.

Thanks again!

Victoria writes:

This sounds like Cyclospora cayetanensis, complicated post treatment by lactose intolerance as a result of the flattening of the villi of the upper intestine. 

Her symptoms of anorexia and lack of fever (present in only about 1/3 of cases), as well as the response to trimethoprim further support this. 

Most interestingly, C. cayetanensis is named for the Cayetano Heredia University in Peru, where much of the initial description of the epidemiology and symptoms was done (also home of the famed Gorgas Course!)

Victoria Weaver, MD FRCPC

Adult Infectious Diseases PGY5

University of British Columbia

Adam writes:

Hi!

My guess for case 180 is Cyclospora cayetanensis or Cystoisospora belli, based on that they fit the clinical picture and are the only known disease causing intestinal protozoans I could find that can be treated with trimethoprim-sulfamethoxazole (Blastocystis hominis would probably not cause this kind of acute disease[?]).

Also, I must tell you that I recently got accepted for a residency ininfectious diseases, and will move to Skövde in southern Sweden. A long time dream is finally coming true!:)

Best regards,

Adam Oscarson, currently in Halmstad, Sweden

Sophia writes:

Hello twip team

I remember suffering from similar symptoms of diarrhea after a trip to Albania many years ago. I had a similar type of meal (a little bit of everything including salad) and decided to go see a doctor after 2 weeks of unabated diarrhea. It had never happened to me. I thought that diarrhea always stops after a while. Anyhow, I did get my antibiotics for 7 days and prompt resolution of symptoms. No lactose intolerance afterwards though. I still wonder what I had (only because I don’t want to get it again!). So in this case I think that the diarrhea is caused by a bacterial agent. The lactose intolerance could be due to Giardia that is also treated with antibiotics. I don’t know what Dr. Griffin was thinking: is Giardia cleared a long while after the antibiotic treatment? do the patients need to be re-evaluated before a 2nd dose of antibiotics is given? Now, it could be that the antibiotics caused the cramps but this is twip so I had to think of a parasite. After all the diarrhea and the medication it takes a while for your gut to get back to normal anyway (not to mention to get all your energy back). In short, I don’t think Giardia caused the diarrhea but it’s the only parasite I can think of that will cause the lactose intolerance. Or maybe I’ve missed something.

Greetings and happy spring!

Sophia

Renee writes:

Hello,

I’m a long time listener and a research assistant with Seattle Children’s Research Institute. I assist with screening hundreds of compounds and their ability to kill M. tuberculosis. Your podcasts played a large part in my decision to pursue microbial research and TWIP did something even I couldn’t do: get my fiance (a mechanical engineer) mildly interested in biology. Now for the case study. I immediately thought of giardia because of the post infection lactose intolerance. However, the patients’ lacked the foul smelling steatorrhea and I’m not used to seeing trimethoprim/sulfamethoxzole prescribed for giardia. A quick Ctrl + f through PD7 for everything with watery diarrhea and trimethoprim/sulfamethoxzole yielded Cyclospora cayetanensis. I think this parasite can also induce lactose intolerance in recovered patients, I couldn’t find a super clear answer on that. I would order a stool PCR to confirm.

Thank you,

Renee

James writes:

Young women actually ate food in Uganda and got watery diarrhea. Who would have guessed?

Of course my first guess, totally avoiding the name of the podcast, would be E. coli traveler’s diarrhea! Since we use Trimethoprim-Sulfa for E. coli urinary tract infections, perhaps it might work for GI bugs although as the Borg might say, “Resistance makes it futile.”

Cholera also comes to mind as a possibility here.

But, this is TWIP right?  The only “parasite” that immediately jumped to mind when you said trimethoprim-sulfa is Pneumocystis, but that is now classified as a fairly unique fungus. (shows how old Professor Small is.) I thought about Giardia which is basically everywhere but have never heard of Sulfa for that—it’s a anaerobe and so metronidazole works.

So out came Googleina. I put in “parasite trimethoprim sulfa” and up came my guess: Cyclospora. I’ve never seen a case (well, recognized a case more precisely). I knew it was a round organism that often stains acid fast, if you think to do an acid fast stain. I don’t think that is routine so if you want the AFB stain you need to order it. Cryptosporidium can look very similar by the way and is also bright red on AFB. Cyclospora can be found luminally in intestinal epithelial cells. Seems it was first described in chimps from…Uganda!

The milk sensitivity, which sounded a lot like my post-Giardia lactose intolerance, took me once again to the Mighty Google. She tells me that several GI infections can make one lactose intolerant for varying periods of time, including Rotavirus (yeah TWIV), Giardia (which caused my kids to call me Mr. Stinky), Cryptosporidium, and…Cyclospora!  (Alexa was of no help. She just told me there’s no cure for lactose intolerance and forgot that I mentioned cyclospora.)

James M. Small, MD PhD, FCAPAssociate Professor of PathologyAchieving New Heights in MedicalEducation
Rocky Vista University

Cecelia writes:

Dear Doctors, 

   I think the people living in the staff guest house are infected with Cyclospora cayetanensis. They are experiencing frequent bouts of diarrhea after they returned from a trip where they consumed fresh fruit and vegetables. The above are known to be sources of infection. They were also exposed to fresh water since the area they were visiting has waterfalls. 

   According to PD7 trimethoprim/sulfamethoxazole is one of the suggested treatments for Cyclospora infection, and the affected individuals improved after beginning a week long course of treatment.

   Cyclospora, like some other parasitic infections, can cause malabsorption. That can explain the severe cramping experienced by one of the individuals after consuming coffee with milk.

   Thank you again for a great podcast and a learning experience for me and your other listeners.

Sincerely,

Cecelia 

Saint Petersburg, Fl 

Peter writes:

Dear super spreaders of American TWIPanosomiasis

In the case study from TWIP 180, two travellers who visited Uganda and consumed local food presented with watery diarrhea that resolved after treatment with trimethoprim/sulfamethoxzole. This combination, sold under the trade name Bactrim, is recommended [1] for treatment of  Cyclospora infection. 

The infection is caused by the coccidian parasite, Cyclospora cayetanensis. This parasite has been described [2] in chimpanzees from Uganda, and, according to Parasite Diseases 7th edition, causes “watery diarrhea with 5–15 bowel movements per day”. Infection is via fecal-oral route and can occur via contaminated food, perhaps in the outdoor meal consumed one week prior to onset of symptoms.

The sporozoites attach to the epithelial cells of the small intestine, causing disruption that can lead to malabsorption of liquids. In the case of milk, malabsorption can lead to lactose travelling to the large intestine where it is fermented, causing abdominal bloating and cramps. [3] This lactose intolerance should resolve itself as the intestinal epithelium heals over the course of a few weeks.

Other parasites considered:

Cryptosporidium parvum,  Balantidium coli, Strongyloides stercoralis and Diphyllobothrium latum. All of these parasites have watery diarrhea as a symptom, but none of them is treated using trimethoprim/sulfamethoxzole. The cure gave the diagnosis in this case.

Peter, writing from Cape Town, South Africa, where the mornings are getting a bit colder but the days remain sunny and warm.

[1] Cyclospora infection, Mayo Clinic: https://www.mayoclinic.org/diseases-conditions/cyclospora/diagnosis-treatment/drc-20353074

[2] Human infection with cyanobacterium-like bodies. Ashford et al. The Lancet, April 1993. https://www.thelancet.com/journals/lancet/article/PII0140-6736(93)91133-7/fulltext

[3] Pathophysiology of Diarrhea, VIVO Pathophysiology http://www.vivo.colostate.edu/hbooks/pathphys/digestion/smallgut/diarrhea.html

Melissa writes:

Dear Vincent, Dickson, and Daniel,

Giardiasis.

If it looks like a duck, walks like a duck, and quacks like a duck, it’s a duck.

Giardia is one of the most frequent causes of traveller’s diarrhea. Other symptoms include cramps, fatigue, and loss of appetite. Symptoms of the volunteers, check. Giardiasis develops after an incubation period of 1 – 14 days, which again fits the description in the case. The two volunteers likely picked it up at the waterfall; contaminated water or food are common causes. And lastly, cramps associated with milk (or lactose intolerance) is commonly observed in individuals with/recently recovered from giardiasis. This tends to be temporary and will likely go away in a couple weeks. Last symptom, check.

The treatment recommendation for giardiasis is metronidazole, tinidazole, or nitazoxanide. I am not super sure why Daniel recommended trimethoprim/sulfamethoxzole. Trimethoprim and sulfamethoxzole are both antibiotics, trimethoprim is mostly effective against gram-positives while sulfamethoxzole is effective against both gram-positives and negatives. My guess is the volunteers’ initial symptoms were too general for a specific diagnosis, so trimethoprim/sulfamethoxzole was recommended as it is commonly used for traveler’s diarrhea.

Thank you Daniel, Dickson, and Vincent for all the work you put into this amazing podcast.

Here’s an alcoholic beverage that I think Dickson might particularly enjoy.

WesternU Global Health Track Students: Dana, Steven, and Chris write:

Hello TWiP professors, 

We believe the most likely diagnosis to be Giardia given their high number of diarrhea episodes and subsequent lactose intolerance. Persistence of symptoms and lactose intolerance could last for weeks to months following infection so the patients may need to be retreated with Metronidazole. 

Differential diagnosis would include Cyclospora cayetanensis, Cryptosporidium parvum, and Entamoeba histolytica. 

Sincerely, 

WesternU Global Health Track Students: Dana, Steven, and Chris

Daniel writes:

Ciao hosts,

Greeting from Italy. I’m a PhD student at the University of Padova studying circadian rhythms and immune responses in insects. The weather has been fantastic, without a cloud in the sky all year. I’m living in Veneto, a region badly hit by Covid-19,  and thought the university has made great efforts to stop the spread here by cancelling all classes and any form of students or staff grouping, we hit the 1,000 patient mark this weekend, in Italy. However, today I didn’t see a single person on my cycle to the lab. Why? It started raining last night… So there may be a simple solution to the problem.

Anyway, sorry, wrong podcast. 

For my guess regarding the case study I am split between two pathogens, Cystoisospora belli and Cyclospora cayetanensis, both of which causes watery diarrhoea and where the infection is typically caused by fecally contaminated food. Both are also treated with trimethoprim-sulfamethoxzole. 

Daniel mentioned specific foods (e.g. Raspberries) and looking through the PDF of Parasitic Diseases I think, Daniel was thinking Cyclospora is the culprit. So I’m guessing the two women had a tough bout of Cyclosporiasis caused by C.  cayetanensis from fecally contaminated food. 

Thanks again for the amazing work you all do, I love the podcasts  (all of them) and you keep me sane during my lonely PhD lab work and also during this crazy virus lockdown.

I won’t stop guessing until I win a book! And even then I will continue. 

All the best,

Daniel

Kevin writes:

Disinfection, decontamination, fumigation, incineration. That aught to teach diarrhea a lesson.

2 young female nurses, Uganda, 7 days post-countryside tour=diarrhea watery severe. No blood. Prompt resolution with TMP/SMX. Post-diarrhea lactose intolerance…..

I’m spending so much time listening to TWiV for coronavirus updates that I’ve been neglecting answering the TWiP 180 case. I will be uncharacteristically brief.

Our afflicted patients have a food borne illness, specifically protozoal gastroenteritis with diarrhea complicated by a post-infectious functional gastrointestinal disorder. This is basically a case of traveler’s diarrhea, which we discussed on 02/27/2019 (TWiP Case 166 presented on TWiP 167). Since our focus is parasitology we can dispense with the many bacterial and viral causes of gastroenteritis. Helminths such as stronglyoides may cause diarrhea, but the clinical scenario here is not consistent with a worm infection. The quick resolution with trimethoprim/sulfamethoxazole (TMP/SMX) strongly implicates Cyclospora as the culprit. A 2017 prevalence study of protozoal infection in western Uganda showed that 36% of their sample (n=200) had protozoal infection and 3.5% had Cyclospora. Consideration may also be given to Cystisopora infection, which is also treated with TMP/SMX. 

The emergence of gastrointestinal symptoms with milk consumption after resolution of the acute diarrheal illness is consistent with acute post-infectious functional gastrointestinal disorder, here manifested by lactose intolerance due to hypolactasia (transient deficiency of intestinal lactase). This will likely resolve after several weeks, but chronic GI disturbances can occur and evolve into post-infectious irritable bowel syndrome. All patients with a resolved acute gastroenteritis of whatever etiology, should be counseled on dietary discretion such as avoidance of dairy for 2-4 weeks, avoidance of fried food, greasy food, and decreased consumption of concentrated sugars and indigestible carbohydrates such as sorbitol and xylitol. 

In the interest of completeness it should be mentioned that whenever symptoms change or remain in a treated gastroenteritis patient, persistent infection, co-infection, reinfection must be considered.

Relevant supporting references are in the Endnotes. 

Thanks for your ongoing efforts.

ENDNOTES:

Letter to NEJM editor re:enteropathogens in the returning traveler rev. 2013

With respect to cryptosporidium, there is no hard evidence (or published data) to indicate that this organism may represent 20% of the global burden of traveler’s diarrhea. Despite the limitations of the GeoSentinel Surveillance Network stated in the introduction of the review, the prevalences of cryptosporidium and cyclospora were shown to be less than 1% (1.2 cases of infection per 1000 returned travelers) in the 42 specialized travel or tropical-medicine sites located around the world.

Swaminathan A, Torresi J, Schlagenhauf P, et al. A global study of pathogens and host risk factors associated with infectious gastrointestinal disease in returned international travelers. J Infect 2009;59:19-27

Okhuysen PC. Traveler’s diarrhea due to intestinal protozoa. Clin Infect Dis. 2001 Jul 1;33(1):110-4

...in travelers, most common protozoa are giardia, cryptosporidium parvum and entamoeba histolytica, with smaller contributions by Isospora and cyclospora. Bacteria remain the most common agent causing diarrhea, but various studies show that 0-12% of acute diarrhea in travellers can be due to protozoa. bacterial diarrhea tends to be acute. Chronic traveler’s diarrhea is more often protozoal.

This 2001 reference is out of date in several sections.

Protozoal Diarrhea Incubation periods (source: CDC unless otherwise specified) / treatments

Giardia: 1-14 days    metronidazole

Cyclospora: 2-14 days   TMP/SMX

Cryptosporidium: 2-14 days  nitazoxanide

Entamoeba: 14-28 days   metronidazole, tinidazole

Cystisospora: 3-14 days   TMP/SMX DS BID x 7-10 days (source Medscape)  

Microsporidium: undetermined   albendazole (Albenza) and fumagillin   https://aidsinfo.nih.gov/guidelines/html/4/adult-and-adolescent-opportunistic-infection/324/microsporidiosis. and waterpathogens.org

Trimethoprim-sulfamethoxazole (TMP-SMX), sold under the trade names Bactrim*, Septra*, and Cotrim*, is the medication of choice for Cystoisospora infection. The typical treatment regimen for adults is TMP 160 mg plus SMX 800 mg (one double-strength tablet), orally, twice a day, for 7 to 10 days.

Ross AG, Olds GR, Cripps AW, Farrar JJ, McManus DP. Enteropathogens and chronic illness in returning travelers. N Engl J Med. 2013 May 9;368(19):1817-25.

from the AGP Ross NEJM rev:

Coccidian parasites such as cyclospora, cryptosporidium, microsporidia, and isospora are increasingly recognized as causes of travelers’ diarrhea, but their percentages may have been underestimated in the GeoSentinel survey, since the diagnosis of these organisms requires specific staining techniques that are not routine in many laboratories.

Prevalence of Intestinal Protozoan Infections and the Associated Risk Factors among Children in Bushenyi District, Western Uganda, Ibrahim Ntulume et al. International Journal of TROPICAL DISEASE & Health 23(2): 1-9, 2017

The prevalence of Giardia lamblia was the highest (16%) followed by Entamoeba histolytica/dispar (13%) compared to Cryptosporidium spp (4%) and Cyclospora spp (3.5%)

Binnicker MJ. Multiplex Molecular Panels for Diagnosis of Gastrointestinal Infection: Performance, Result Interpretation, and Cost-Effectiveness. J Clin Microbiol. 2015;53(12):3723–3728. doi:10.1128/JCM.02103-15

diagnosis—microscopy, multiplex molecular panel

This review highlights three commercial multiplex panels (FilmArray GI panel [BioFire Diagnostics, Salt Lake City, UT], Luminex xTag GI pathogen panel [GPP] [Luminex Corporation, Toronto, Canada], and Nanosphere Verigene enteric pathogen [EP] test [Nanosphere, Inc., Northbrook, IL]) that have been cleared by the Food and Drug Administration (FDA) for the detection of GI pathogens (bacteria, virus, and/or parasites) from clinical stool samples.

NOTE: it looks like Luminex acquired Verigene.

DIAGNOSTIC CONSIDERATIONS:

THE BIOFIRE GI PANEL MENU

Overall 98.5% Sensitivity and 99.2% Specificity9

Sample Type: Stool in Cary Blair

BACTERIA:

Campylobacter (jejuni, coli, and upsaliensis)

• Clostridium difficile (toxin A/B)

• Plesiomonas shigelloides

• Salmonella

• Yersinia enterocolitica

• Vibrio (parahaemolyticus, vulnificus, and cholerae)

• Vibrio cholerae

DIARRHEAGENIC E. COLI/SHIGELLA:

Enteroaggregative E. coli (EAEC)

• Enteropathogenic E. coli (EPEC)

• Enterotoxigenic E. coli (ETEC) lt/st

• Shiga-like toxin-producing E. coli (STEC) stx1/stx2 

• E. coli O157

• Shigella/Enteroinvasive E. coli (EIEC)

PARASITES:

Cryptosporidium

• Cyclospora cayetanensis

• Entamoeba histolytica

• Giardia lamblia

VIRUSES:

• Adenovirus F40/41

• Astrovirus

• Norovirus GI/GII

• Rotavirus A

• Sapovirus (I, II, IV, and V)

Luminex xTAG Gastrointestinal Pathogen Panel (GPP)

Bacteria and Bacterial Toxins2

Campylobacter

Clostridium difficile, Toxin A/B

Escherichia coli O157

Enterotoxigenic E.coli (ETEC) LT/ST

Shiga-like Toxin producing E.coli (STEC) stx1/stx2

Salmonella

Shigella

Vibrio cholerae4

Yersinia enterocolitica

Viruses

Adenovirus 40/41

Norovirus GI/GII

Rotavirus A

Parasites

Cryptosporidium

Entamoeba histolytica

Giardia

for a list of FDA approved multiplex array diagnostic tests

https://www.fda.gov/medical-devices/vitro-diagnostics/nucleic-acid-based-tests

Microsporidium:

uncertain taxonomic status…

CDC:

The microsporidia are a group of unicellular intracellular parasites closely related to fungi, although the nature of the relation to the kingdom Fungi is not clear. The taxonomic position of this group has been debated and revised repeatedly; historically, they were considered protozoa and often remain managed by diagnostic parasitology laboratories. Microsporidia are characterized by the production of resistant spores that vary in size (usually 1—4 µm for medically-important species)

POST-INFECTIOUS GASTROINTESTINAL DISORDERS.

DuPont AW. Postinfectious irritable bowel syndrome. Clin Infect Dis. 2008;46(4):594–599. doi:10.1086/526774

Deising A, Gutierrez RL, Porter CK, Riddle MS. Postinfectious functional gastrointestinal disorders: a focus on epidemiology and research agendas. Gastroenterol Hepatol (N Y). 2013;9(3):145–157.   Dietary Intolerance: Protozoal and other infections of the small bowel may cause a malabsorptive syndrome. Hypolactasia, a transient deficiency of lactase that may manifest as new lactose intolerance and chronic diarrhea, is well characterized in children following IGE (infectious gastroenteritis) and may occur in adults. More recently, evidence has emerged suggesting that celiac disease may be triggered by acute enteric infection. A number of case reports have described infectious diarrhea as a trigger for celiac disease with limitations in the ability to determine if the enteric infection was a trigger or somehow unmasked the symptom onset and diagnosis, 

Landzberg BR, Connor BA. Persistent diarrhea in the returning traveler: think beyond persistent infection. Scand J Gastroenterol. 2005;40:112-124.

A TERMINAL CURIOSITY:

One of the thrills of being an altar boy in the 60s was serving at a funeral mass. There was a great deal of medieval ceremony, the chief one being the burning of incense. The censor was attached to a long chain and the priest would slowly rock it around the deceased, letting out great clouds of smoke that drifted up to the rafters. The aroma of frankincense was transporting. 

Recent international television footage from coronavirus stricken areas showed workers in protective gear wielding firehose sized equipment letting out massive plumes of unknown vapor. I figured that this ritual was meant to assuage the populace. Speaking of medievalism, the whole idea of fumigation recalls the black death, beaked masks full of herbs, self-flagellation and animal sacrifice. My immediate reaction to fumigation in relation to the current coronavirus outbreak was extreme skepticism. Then I doubted my skepticism, prompting the question: What is the role of fumigation in epidemic virus infection control?

Fumigation is currently used in grain decontamination, rodent control, and in some animal husbandry applications (e.g. foot and mouth disease control in animal facilities)….and fumigation was used successfully in the inactivation of anthrax spores in the post-9/11 bioterror incident.

Nevertheless, multiple literature searches in PubMed and general Google searches using a wide variety of search strings did not turn up any usable references that described the efficacy of fumigation for surface/environmental contamination with human disease causing viruses. My tentative conclusion is that fumigation in coronavirus control is reminiscent of medieval plague practices. I remain open to contradiction. 

Various references on this topic follow below:

The risks and benefits of chemical fumigation in the health care environment. Byrns G, Fuller TP.  J Occup Environ Hyg. 2011;8(2):104–112 chemicals mentioned: quarternary ammonia, hydrogen peroxide vapor (HPV), paraformaldehyde, ozone, superoxidized water, chlorine dioxide. No mention of efficacy in virus outbreaks. HPV is used in UK for decontamination of hospital rooms targeting E.coli and MRSA.authors conclusion:Fumigation in health care facilities and other related institutions should be limited to those instances where the benefits clearly exceed the risks of human exposure or environmental damage. Decontamination of an unoccupied building following a bioterrorism incident would meet this criterion

Lutgen M. Chlorine dioxide remediation of a virus-contaminated manufacturing facility. PDA J Pharm Sci Technol. 2011;65(6):620–624

Chlorine dioxide fumigation was successfully used to decontaminate a virally contaminated biotech manufacturing facility. Addressing safety, product quality, and corrosion risks were important factors in planning the building fumigation. Studies were performed to define the conditions in which minute mouse virus (MMV) is inactivated by chlorine dioxide and to understand equipment and facility risks.

The sensitivity of some avian viruses to formaldehyde fumigation. Ide PR. Can J Comp Med. 1979;43(2):211–216. Focus on poultry/chicken agriculture. The discussion states “it is almost impossible to fulfill all these under field conditions…”

Camphor–a fumigant during the Black Death and a coveted fragrant wood in ancient Egypt and Babylon–a review. Chen W, Vermaak I, Viljoen A. Molecules. 2013;18(5):5434–5454. Published 2013

Handbook for management of public health events on board ships. WHO publication 2005

No mention of fumigation for viral disease. Mention of International Maritime Fumigation Organisation. mostly for pest control

Tognotti E. Lessons from the history of quarantine, from plague to influenza A. Emerg Infect Dis. 2013;19(2):254–259. doi:10.3201/eid1902.120312

The CDC mention of fumigation: (note that most CDC citations are for fumigation related poisonings)  

https://www.cdc.gov/smallpox/bioterrorism-response-planning/healthcare-facility/prevent-spread-disease.html

Healthcare facility response to smallpox / bioterrorism response planning.  Ambulances: Disinfect ambulances using EPA-registered hospital disinfectants approved to inactivate vaccinia virus (as described above). Follow manufacturer’s recommendations for use. Fumigation of the interior space is not indicated. Follow guidelines for disposal of medical waste, including disposable medical instruments and patient-care devices, and PPE. Follow instructions for proper handling of patient laundry. Do not transport any non-smallpox patients in the vehicle until disinfection has occurred.  Interior surfaces of spaces occupied by smallpox patients: Disinfect non-porous surfaces using EPA-registered hospital disinfectants approved to inactivate vaccinia virus (as described above). Fumigation of rooms, facilities, or vehicles is not indicated for environmental control of variola virus.

Fumigation of clothing during an 1865 cholera outbreak at the French-Italian border

Sophia writes:

sorry guys, I have a question from last time that’s been itching me: so if you’re infected with worms and get cholera and then typhoid, how does your gut respond to that? and how do you make it through? isn’t it too much? I know I would be dead. Do the parasites make it worse for someone to get cholera on top? or can the cholera affect the worms? 

Thanks very much.

Greetings from Greece

Vic writes:

Hi Doctors TWIP!

This has absolutely nothing to do with TWIP,  but I ran across this video: https://youtu.be/ZD_3_gsgsnk .

I thought Dr. Despommier, would be interested to hear that folks in Alliance, Nebraska are doing indoor agriculture on the cheap.

Best,

Vic