Galen writes:

Hello doctors,

I’m hoping I make it in before the deadline this time. I’ve been listening since I was in Peace Corp Uganda and had a case of schistosomiasis in 2011 and I’ve been a faithful listener since.

I’ll have to keep this brief as I’m working the night shift on labor and delivery,  but I think this patient has a case of babesiosis and unfortunately sounds like a fairly severe case. The RBC inclusions and treatment suggest babesiosis. His other lab abnormalities and signs/symptoms are also seen to varying degrees including dark urine from hemoglobinuria due to severe intravascular hemolysis.  How profound was his anemia and thrombocytopenia? Was his poor mobility due to pain, weakness, dyspnea? Though he denies it he may have had a tick bite that he’s not aware of. Malaria is less likely given no recent travel out of the country.

Thanks so much for the hours of learning. I’m always hopeful to get some hands on experience with parasitic diseases as a rural family medicine resident but so far nothing beyond a few cases of giardiasis,



Chad writes:

Hello TWiPpers,

Daniel, thank you for sharing another case study. Atovaquone is used to treat toxoplasmosis, malaria, pneumocystis pneumonia and, finally, in conjunction with azithromycin in mild to moderate cases of babesiosis. My guess is Babesia Microti. This newly wheelchair bound patient in this case is beyond mild to moderate and should be started on IV clindamycin with oral quinine or IV quinidine.



Martha writes:

Dear TWiPers, 

I hope this letter finds you well and parasite free. I’m attempting to be a bit less late to the case.

In the case of the previously fit and well 70 year old man with progressive weakness and fevers, who has anemia and thrombocytopenia, the question that was not asked was: ‘what was the shape of the erythrocyte inclusion?’  And does he take a dip in a vat of DEET prior to his runs through the woodlands? (I find it unusual that for 7 decades no arthropod has shown any interest in him.) Since we have been told he has no significant medical history I assume he is immune competent (as much as one can be at 70 years old) and that he has a spleen.

If the shape of the inclusion is of a Maltese cross, then in spite of the lack of tick attack history I think that this is a case of Babesiosis, which is usually caused by Babesia microti carried by the tick Ixodes scapularis, formerly known as Ixodes dammini. The thrombocytopenia, hemolytic anemia and hemoglobinuria all weigh in favor of this. Also suggestive is the prescription for Azithromycin and Atovaquone. 

Since this is such a severe case, it is probably worthwhile considering a co-infection with Borrelia burgdorferi which is carried by the same tick. Fortunately, Azithromycin is one of the recommended treatments for Lyme disease. We are not told how long he has been on Azithromycin and Atovaquone. Has it been long enough that we need to consider a resistant organism? 

I look forward to the discussion of this case.

Best wishes to all of you


P.S. I have won and received a book, thanks

Paul writes:

The case of the healthy, fit, older man with a febrile illness, hemolytic anemia, low platelet count, abnormal liver tests, extreme fatigue, no travel history, living in Queens with outdoor activities in parks is most consistent with disease caused by Babesia microti.

The diagnostic clue of red blood cell inclusions followed by prescription of azithromycin and atovaquone suggests that the inclusions seen on a standard thin blood smear (Giemsa or Wright stained, the common practice), were  variable-shaped ring forms of Babesia trophozoites.  Rarely, a tetrad of merozoites are seen in a “Maltese Cross” formation which is considered diagnostic (or pathognomic) for Babesia. 

Babesia microti is endemic New York City with 86 cases identified in 2020. It is spread by the Ixodes scapularis tick which also can carry B. burgdorfii (causing Lyme disease) and Anaplasma phagocytophilium (causing human granulocytic anaplasmosis).

The nymph tick transmits Babesia to humans and the bite is often not recognized as the nymphs are less than 2 mm in size or poppy seed size, hence the patient did not recall a bite.

Most cases of Babesia improve within two days of treatment, but this patient was not improved.  There are several possibilities. The only reported risk factor for more severe disease is his age, but the possibility of underlying immunocompromising illness should be considered. No clues are given to such an underlying condition.  He could be co-infected with one of the other pathogens mentioned above, however the course is not compatible with Lyme disease but could be Anaplasmosis (which is much rarer in NYC).

Next steps would include confirming the diagnosis with PCR, and treating the patient with IV azithromycin and oral atovaquone or IV clindamycin and quinine sulfate and considering exchange transfusion.

Thanks, I learned a lot.


Marcus writes:

Dear TwiPers, your cases may give me nervous ticks, but I suppose that is my (Maltese) cross to bear.

I worry my case guesses from my private email don’t get through; so this time I am trying from work again.

Our patient is a healthy man, no travel history, denies insect bites (though active runner/cyclist – likely bitten at some point without noticing). 2wk history of fatigue and febrilia. Pancytopenia, rbc inclusions, likely hemolysis with hemoglobinuria. 

Assuming that the rbc inclusions are microbial (though howell jolly bodies in asplenia would be relevant here), I once learned that the erythrocyte is an uncommon target for pathogens, as it has little intracellular machinery, doesn’t replicate and has a lifespan of only 120 days. Indeed, we only have three important intracellular pathogens of erythrocytes – Malaria, Bartonella and Babesia. Though possible with airport malaria here, Babesia seems more likely, and Bartonella wouldn’t quite fit with TwiP. 

Babesia alone, however, rarely causes such severe disease. Severe illness is usually associated with immune compromise (as in previously mentioned asplenia) or coinfections with Lyme disease or Anaplasmosis. A coinfection with anaplasma seems more likely if his runs have taken him to Long Island, though it may well be severe Lyme, as we know all these three tick borne diseases are on the rise in the NE USA. 

So that is my guess for this case – Babesiosis with possible immune compromise or Anaplasma/Borrelia coinfection. Relevant ELISA, blood PCR and a proper look at the blood and buffy coat smears would inform further care. Though atovaquone+azithromycin are first choice in mild Babesiosis, quinine and clindamycine are preferred in severe disease. Furthermore, doxycycline should be considered for anaplasma/borrelia.

Writing you on a cool sunny day on holiday in Southern Norway – where there is plenty of Lyme, and TBE is on the rise, but to my knowledge no Babesia or Malaria (though there are Anopheles mosquitos);

Best wishes,

Marcus Glenton Prescott

Faculty of Medicine/St. Olavs Hospital

Norwegian University of Science and Technology (NTNU)

Inge writes:

Dear doctors of TWiP, 

It’s been a sunnier day than the average all week with temperatures just above 20 Celsius – weve had a lot of rain in the Netherlands. The emergency department where I’ve recently started is finally calming down on my evening shift so I have some time to train my brain on this new case.

Thanks again for such an interesting paper on malaria and the most recent case presented. I must say, my first thoughts immediately went to malaria, with inclusion bodies in RBC’s, anemia and thrombocytopenia and the typical chills with fever. I didn’t find the clinical course of 2 weeks fitting, nor the location of residence of the patient and absence of a significant travel history. So I took to the books and I will put my guess towards babesiosis. Being from Northern Europe, this is not a disease I was familiar with but it seems to fit the picture well. With similar attack on the RBC’s causing inclusion bodies, hemolytic anemia with hemoglobinuria and a milder picture. It being prevalent in the state of New York and transmitted by ticks, our patient has probably received it during one of his outings to the park. To confirm the diagnosis I would like to have a thin blood smear done with Wright’s or Giemsa stains. Azithromycin and atovaquone is a very fitting therapy and I would suggest, if the patient isn’t increasingly ill or with dangerous levels of anemia and thrombocytopenia, to keep him at it for a while longer. Of course switching to clindamycin and quinine can be considered, also IV options. With malaria being somewhat similar in presentation, it would be my preference to do a thick blood smear along with the tests. I wouldn’t find it very likely epidemiologically, but with climate change causing mosquitoes to behave differently we should be aware of the theoretical possibility. 

I am very curious to hear whether my diagnosis is correct or not and what your advice on treatment with the current presentation would be and whether it would qualify me for winning a book, which I haven’t as of yet. Would I meet this patient in my ED I would feel much more comfortable consulting the infectious disease specialist on this before acting out my ideas of course. 

Kind regards,

Inge Mulder-Vos

Ps. I noticed you don’t seem too fond of ChatGPT, but if you’ll have me, I would like to challenge this opinion a little. I would say that for anyone who would otherwise use Google or the register of their textbook for inspiration when assessing a case, ChatGPT might be an equally worthwhile or even better way to go. As always none of these resources should be used as sole resource for clinical reasoning and definitely not as sole source for patient treatment. But they are very valuable when puzzling away at a case. Any facts should always be corroborated, but when taking in good common sense precautionary measures I think we can all benefit highly from their existence. I hope I didn’t elaborate too much or push too many buttons, just thought it was worth mentioning

Sean writes:

Hi all,

I am writing in from the usually sunny Okanagan valley that is unfortunately laying under a thick blanket of smoke from the nearby wildfires. Upon hearing of something hiding in the red blood cells of our patient here along with intermittent fever and elevated liver markers, my first thought was malaria. As far as I know however, one’s chances of contracting that while running through a park in Queens are quite low. Using this same geography to rule out trypanosomiasis, lead me to a diagnosis of Babesia infection.

It seems that this somewhat infrequent human parasite hangs around in the very same tick species that carry our old friend Lyme disease around the northeastern united states. My follow up investigation would be whether or not our patient has some type of coinfection along with the Babesia as it usually does not cause such severe disease in otherwise healthy people. Could this explain why the azithromycin and atovaquone therapy yielded no improvement? Or is it possible that there is some previously undiagnosed immunocompromising pathology in our patient?

Thanks again for all you guys do educating us laymen on the world of parasites,


Felix writes:

Dear Twip Team,

Greetings from Germany! I just finished my intern year and final exam but unfortunately didn’t get a position in the new infectious disease residency program over here. Well, so general internal medicine it is!

I did send my last emails too late as usual, so now I try to keep it short, but in time.

After toxoplasmosis and Cystoisospora Canis, I now suspect the third Apicomplexa sighting in a row. The RBC inclusions and other lab findings are suggestive for Babesiosis or malaria. Since the patient denies traveling to a malaria risk area, Babesiosis would be highest on my list of parasitic differentials even though the patient denied being bitten by a tick (but those can be sneaky).

For diagnosis a blood smear and, if still unclear, PCR could be performed.

Depending on the patient condition supportive therapy as well as a switch to Quinine and Clindamycin or exchange transfusion in parasitemia bigger than ten percent could be considered.

I am looking forward to the episode with the first Vienna Parasitology passion club. When I tried to Google it, all I found was a night club named with three of the five words, you can guess which.

Thank you for the great monthly education!

Wish you all the best.


Rafid writes:

Hello TWIP team,

I am a rural internist with a very broad based practice who has been working in small town called Maniwaki ( which is Algonquin for the land of Mary ) in Quebec about 2 hours north of the nation’s capitol for the last 25 years. Four years ago McGill university set up a satellite medical campus in a town called Gatineau close to my work and was looking for French speaking lecturers. So I volunteered to give some of  the French versions of the original English Montreal  McGill lectures. This gave me access to the whole catalog of the videos of the English McGill first year medical lectures. The McGill curriculum is fantastic and I now have the wonderful opportunity to listen to the latest developments in neurology, nephrology immunology etc..

The best teaching block by far though is the infectious disease block. The ID block is organized by the fantastic Christos Karatsios who is a wonderful teacher and it contains a 5 hour parasitology section that is taught by Michael Libmann who is one of the best, funniest and entertaining teachers that I have ever run across. A model lecturer so a shout to him on the chance that he is listening. He has definitely made me a much improved my ID/parasitology skills.

So as to this case of the patient from the American north-east who regularly jogs in a wooded area and now has fever,  hemolysis ( dark urine ) thrombocytopenia, elevated liver enzymes and inclusion bodies in the erythrocytes, I think the most likely diagnosis is babesiosis with parasite Babesia microti. I would be interested to know from the members of the TWIP team if this can be Malaria ? I teach a small group session on malaria and the case that I present to the students has EXACTLY the same except that the patient travelled to India instead of taking a run through Queens, however Dr. Libmann says that in the 19 th century there was Malaria during the summer in Montréal brought over by immigrants as well as local anopheles mosquitoes. He also says in his lectures that there is anopheles in the New York area and that it creeping North due to global warming  I also read recently that the southern US has had some P. Vivax malaria.  Also The basic message that I am told to teach the medical students is 1. Fever in a returning traveller is Malaria until proven otherwise 2. Malaria is falciparum until proven otherwise. So given his presentation and his worsening symptoms  despite appropriate anti Babesia therapy with Azithro-Atovacone would the TWIP clinicians be reaching for artemisinins? Looking forward for your opinion from a country doctor who not only has never seen a case of Babesia in the frigid wilds of rural Quebec but completely forgot about this entity the day after my ID exam in first year Med school thirty years ago and only remembered it after listening to Michael Libmann’s lectures.

Thank you all donating your time to make this wonderful podcast possible


Rafid Haidar

Christian writes:

Dear Twip

The description, including the treatment started, which is quite a spoiler, points to Babesia.

The dark urine is a sign of hemolysis. For Dixon, the urine looks like a dark brew of beer.

I was more surprised to read about the babesia carriage rate in ticks in the State of New York, with up to 15%.

One of my main questions would be: Why is this person getting so ill? 

Does he have an underlying immunosuppression? Or is he missing his spleen? Though he is of a certain age, the patient does appear to be a “best ager” being rather fit.

Best Wishes from London


Håkon writes:


Based on inclusion bodies, his active lifestyle out biking in the parks and the recent increases in babesia incidence in the NE this summer- that would be my guess. It seems likely he probably picked up a tick on one of his 15mi bike rides or 3mi daily runs. 


Aracelis writes:

name pronunciation: Ara-chay-lee

Union County NJ

Hello TWIP,

I am a Queens native who now lives in NJ just down the road from Vincent, and the instant I heard this case presented, I knew there had to be a bloodsucking insect involved. I was a teenager when West Nile arrived in NYC, so perhaps I am more aware than most of the ample opportunities for people to get eaten alive out there, even or perhaps especially in the Outer Boroughs.

I also recalled that in a very recent Microbe TV episode Daniel mentioned an up-TICK in local babesiosis cases, so I decided to start with the assumption that this 73 year old gentleman who is an avid outdoor cyclist and runner in urban greenspaces was likely bitten by a tick on one of his outings. Maybe it’s a bit of leap to assume that if Daniel has something on his mind, it’s worth reading about, but I decided to run with this idea, especially as he presented the case by saying he’s seen several of these patients recently, and at least one of them, perhaps this one, is worth a write-up.

My first destination was the NYC Dept of Health’s published statistics on infectious disease, so I could get a sense of what type of parasitic diseases are now endemic to my home borough.

Soon I found myself perusing a helpful little diagnostic booklet produced by the City of New York for primary care doctors, that lists symptoms and suggested courses of treatment for common tick borne diseases: 

Within a few moments I had three candidate diagnoses: The bacterium Anaplasmosis (which I learned causes human disease called HDA), The bacterium ehrlichiosis (which I learned causes human disease called HME), and my original guess, the parasite Babesia microti, which is transmitted in the Northeast by the Ixodes scapularis tick. The PDF guide also gave me the following helpful information; I’ve bolded the symptoms that seem relevant to our case:

  “SIGNS/SYMPTOMS [incubation period: 1-9+weeks] • Fever, chills, sweats • Malaise, fatigue • Gastrointestinal symptoms (anorexia, nausea, abdominal pain, vomiting) • Myalgia, arthralgia, headache • Dark urine • Less common: Cough, sore throat, depression, emotional lability, photophobia, conjunctival injection • Mild splenomegaly and/or hepatomegaly. Babesia infection can range from asymptomatic to life-threatening. Risk factors for severe babesiosis include asplenia, advanced age and impaired immune function. Severe cases can be associated with marked thrombocytopenia, disseminated intravascular coagulation, hemodynamic instability, acute respiratory distress, renal failure, hepatic compromise, altered mental status and death.”


“Common Findings on Routine Laboratory Tests • Decreased hematocrit due to hemolytic anemia • Thrombocytopenia • Mildly elevated hepatic transaminases • Elevated serum BUN and creatinine • Elevated reticulocyte counts • Elevated erythrocyte sedimentation rate • WBC count may be normal or mildly decreased • Decreased serum haptoglobin • Proteinuria • Hemoglobinuria 

Diagnostic Laboratory Criteria • Identification of intraerythrocytic Babesia parasites in a peripheral blood smear (preferred method); or • Positive PCR assay (preferred method); or • Isolation of the parasite from a whole blood specimen by animal inoculation”

The PDF goes on to suggest, for treatment, that: “Fewer side effects have been reported using the combination of atovaquone and azithromycin, but the clindamycin and quinine combination may be indicated for patients with more severe illness. Consult an infectious disease specialist for the most current treatment guidelines or for individual and pediatric patient treatment decisions.” Further, they advise in a set of notes: “For adult patients who are immunocompromised, higher doses of azithromycin (600-1000 mg per day) may be used. • The recommended treatment for patients with severe babesiosis, as indicated by high-grade parasitemia (≥ 10%), significant hemolysis, or renal, hepatic or pulmonary compromise, is quinine and IV clindamycin, and the patient should be considered for partial or complete RBC exchange transfusion. • Consider the possibility of coinfection with B. burgdorferi and/or A. phagocytophilum in patients with especially severe or persistent symptoms, despite appropriate antibabesial therapy.” 

I wonder if the azithromycin/atovaquone dose which this gentleman was Rx’d by his primary care doctor was insufficient for the degree of parasitemia he was experiencing, or if this is a good case study in how and why ID doctors should be consulted as quickly as possible, so they can help confirm a complete and accurate Dx, and choose the correct therapeutic response?

Furthermore, a very helpful page with References was included in the NYC DOH PDF file, and two caught my eye:

Krause PJ, Lepore T, Sikand VK, et al. Atovaquone and Azithromycin for the Treatment of Babesiosis. New England Journal of Medicine. 2000; 343(20): 1454-1458.

†Wormser GP, Dattwyler RJ, Shapiro ED, et al. The Clinical Assessment, Treatment and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis. Clinical Practice Guidelines by the Infectious Diseases Society of America. Clinical Infectious Diseases. 2006; 43(9): 1089-1134. 

While I don’t have the access needed to open this article, I did see yet another cite in the PubMed “related papers” section: Sanchez E, Vannier E, Wormser GP, Hu LT. Diagnosis, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: A Review. JAMA. 2016 Apr 26;315(16):1767-77. doi: 10.1001/jama.2016.2884. PMID: 27115378; PMCID: PMC7758915.

I opened this article because although it is a dreaded meta-analysis, it does post-date the prior citations, and I wondered if ten years has made any difference to the diagnosis and treatment of tick borne disease. I was rewarded by a beautiful image (Figure 4) of the sorts of RBC inclusions you might see in Babesiosis:

The image is captioned: “Figure 4.. Babesia microti parasites in human red blood cells. (A) B. microti trophozoites often appear as rings with one chromatin dot. Arrow points to a classic ring form of babesia. (B) Asexual division of the parasite yields up to four merozoites which can arrange in a tetrad, also known as Maltese cross (see arrow). Maltese crosses can be formed by B. microti, B. duncani, and B. divergens in human red blood cells. (C) Following rupture of an infected red blood cell, free merozoites (see arrow) quickly seek to adhere and invade an intact red blood cell. Micrographs are courtesy of Rouette Hunter and Stephen Johnson from the Hematology Laboratory at Tufts Medical Center, Boston, MA.”

This piqued my interest. Perhaps you can tell us more about the similarities and differences between B. microti, B. duncani, and B. divergens, and the specific reproduction process of Babesia.

I’m not a doctor, or even a scientist, though I did consider becoming an ENT after earning my undergrad degree in philosophy — and was proud to finish my pre-med requirements as a post-bacc at Columbia University. I work in finance as a data taxonomist and modeler, so parasites (the kind that make you sick) are well outside my wheelhouse, and this is the first guess I’ve felt encouraged to send in to you. I hope I’ve done this correctly.

Please continue the amazing work, TWIP is the highlight of my podcast reel whenever a new episode drops, as your enthusiasm for the subject is, yes, contagious.

Eyal writes:

Dear Vincent and the sages of the microscopic eukaryotes.

Greetings from Sydney and the land down under.

Just for the record, I’ve won a book (April 2022) but I believe it was not shipped yet. 

My guess for this episode is Malaria. More specifically, I would guess it is plasmodium falciparum based on severity of the infection.

All the clues Dr. Griffin has give screamed Malaria:

RBC inclusions – Malaria would cause RBC damage

Anemia and thrombocytopenia – due to the RBC damage and inflammation

bilirubin – RBC damange

ALT – Liver damage due to the malaria parasites in the liver

intermittent fever, chills, and dark urine – Malaria, Malaria, Malaria.

After consulting Dr. google I think I understand why our patient wasn’t improving after being treated with azithromycin and atovaquone. azithromycin doesn’t treat the parasite it self. and atovaquone should actually be given together with proguanil under the label Malarone.

So my ignorant recommendation would be to continue treating with Malarone as the patient is definitely telerant to atovaquone already.

It certainly looks like the Endogenous spread of Malaria is picking up in the US and elsewhere. Who knows, maybe Tonic Water is the next big thing…

I find it Interesting, exciting and depressing all at the same time (mostly depressing). 

Keep up all that you do. 

The world needs more saints like you.


@Vincent Racaniello I will love to attend some of your talks if you are still planning on coming to Sydney in September.

Thank you,


Michelle and Alexander from the First Vienna Parasitology Passion Club write:

Dear Babesi-bros,

What walks like plasmodium, quacks like plasmodium, but isn’t plasmodium? Babesia. 

Regarding the case of a 73 year old, otherwise healthy male without significant travel history who presents to the ED with fever and progressive weakness for two weeks. Our guess is that this patient is infected with Babesia microti. Babesia is a tick borne parasite of the Apicomplexa phylum which most commonly presents with flu-like symptoms, fever and hemolytic anemia, though immunocompetent patients with babesiosis are oftentimes asymptomatic. It can be differentiated from Anaplasmosis via detection of hemolysis and from malaria via travel history, antigen testing, blood smear and, if doubts remain, via PCR.

Like during infections with Plasmodium spp., inclusion bodies are often seen on blood smears, which can mimic those found in malaria. A more specific finding is the tetrad “maltese cross” formation. The first line treatment for babesiosis is azithromycin in combination with atovaquone, which is preferred over the combination of clindamycin and quinine, which cause more severe side effects but are used in severe or refractory cases. Rarely, exchange transfusions are necessary. 

Preventative measures include using insect repellents, wearing long-sleeved clothing and performing tick checks after being outdoors. 

Thank you for this great case. All the best, 

Michelle and Alexander from the First Vienna Parasitology Passion Club

Natalya writes:

Dear TWiPpers,

While this patient’s symptoms are relatively non-specific, the chronicity of fever and his lab work raise concern for Babesiosis from Babesia microti. Given that he lives in the Northeast and frequently runs in parks, he could have been exposed to this parasite via a bite from a Ixodes scapularis tick in the recent warm weather months. Initial testing includes a peripheral blood smear, which can sometimes show the merozoites in a tetrad orientation (Maltese cross) if there is a high level of parasitemia. Babesia PCR and species-specific serology testing should be sent as well. While oral Atovaquone and Azithromycin are the appropriate therapy for most cases, he would likely require escalation to Quinine and IV Clindamycin for a 7-10 day course. Depending on his level of parasitemia, he may warrant exchange transfusion. With his acute presentation and the risk of co-transmission from Ixodes scapularis, he could have co-infection with Borrelia burgdorferi and/or Anaplasma phagocytophilum. Depending on his clinical course, his team could consider an empiric doxycycline course.

Thank you for all that you do.


Natalya Beneschott, MD

Pediatric ID fellow

Jeremy writes:

Hello Twipeteers!

This sounds like babesiosis:

– RBC inclusions (merozites show up as rings and crosses on peripheral smear)

– anemia and thrombocytopenia

– dark urine from hemolytic anemia

– treatment is atovaquone and azithromycin

I am not sure about anaplasma prevalence in New York, but here in southern Vermont I would draw for anaplasma PCR and add empiric treatment with doxycycline until this resulted. I know that empiric treatment can curl bowties, but there are times when the benefit far outweighs the risk.

I would continue to monitor platelets, as patients can develop ITP secondary to babesiosis. If he still felt crappy after the resolution of the babesiosis, I would consider Lyme antibodies. 

“Denies tick bites” is a bit like ESR, in that it’s more useful in the negative than the positive. Ixodes nymphs are about the size of a poppy seed and easily missed. Unless he were really looking and had an amazing mirror arrangement, there is a good chance our patient might have missed an attached tick. If he has no intimate partner, I would bring him in for a full body tick check. This could also be a good opportunity to make the more intimate acquaintance of someone he might have admired from afar: “Look, I know this probably seems like a weird thing to ask, but my doctor says that I need someone to check me all over for ticks… I could make you dinner in return maybe?”

Every cloud…


Townshend VT

Kyle writes:

Greetings esteemed TWiPpers,

I am an avid fan of all things Microbe.TV, and, as a science educator, I would like to thank you for continuing to educate me on the wonderful world of microbiology! For our case study (219), my first inclination was malarial infection, though a case of malaria in a New Yorker who hasn’t left the comfortable confines of the Big Apple was a difficult pill to swallow. The mentioning of erythrocyte inclusions accompanied by anemia, on top of the described symptoms of fever and lethargy, would have been a slam dunk if not for the lack of a travel history. Indeed, I decided to do a Google search of malarial cases in New York, which took me to the New York State Department of Health’s website. Here, it said that malarial infections are most commonly associated with travelling to foreign countries, but there have been rare cases of local transmission in Long Island and New York City. 

Case closed??????

I didn’t think it could be that easy, so I decided to look into the second clue provided by Dr. Griffin, which was that the patient was treated with azithromycin and atovaquone. I am familiar with azithromycin, as I am currently working on a graduate certificate in medical microbiology, but atovaquone was new to me. I plugged the two medications into a Google search, and the first hit that mentioned the two together came from an article published in the New England Journal of Medicine. This article describes the use of azithromycin and atovaquone as treatment for babesiosis. Tragically, I was not able to consort with the great authoritative book on parasitic diseases (I think you know which one I am referring to) because I do not own a copy. Abandoning any temptation to consort with ChatGPT (unlike some of my students in some lecture assignments), I decided to dig a little deeper into babesiosis, and lo, it is transmitted by a tick bite! I suppose our patient was unaware of the filthy bloodsucker that was most likely hiding in his hair or darker nether regions where one doesn’t often scan for potential ectoparasites. 

According to the CDC, babesiosis in the Northeast is most likely associated with Babesia microti where it is transmitted through the bite of the tick Ixodes scapularis. The little parasites like to take up residence in the red blood cells (hence, the RBC inclusions), and can cause a variety of symptoms including fever, lethargy, dark urine, hemolytic anemia, thrombocytopenia, splenomegaly, and hepatomegaly. Considering all of this, my diagnosis for our patient is that he has babesiosis from a tick bite that he probably picked up from one of his excursions through the park…now it feels like a slam dunk!

The most common treatment for a case of babesiosis is (no surprise) azithromycin and atovaquone! According to the CDC, it is recommended that the patient take azithromycin for 7-10 days (500 mg the first day, and 250 mg every 24 hours for the subsequent days) and 750 mg of atovaquone every 12 hours for 7-10 days (they mention that atovaquone be taken with a fatty meal, so I assume it is a fat-soluble compound). Alternatively, patients can take clindamycin and quinine. Both drugs come at higher dosages and should be taken every 8 hours. 

I was talking about TWiP with a fellow faculty member several months ago, specifically the case studies! He is a veterinarian by training, and we both teach anatomy and physiology, so I thought he would find your podcast most interesting and informative. I wish more science podcasts were this engaging with their listeners as this one assuredly is. Thank you all for everything that you do!

All the best,