This Week in Parasitism

TWiP reviews gene expression in wood ants infected with the larval lancet fluke, which causes them to leave their nest and attach to a flower until they are eaten by a grazing mammal. Hosts: Vincent Racaniello, Daniel Griffin, and Christina Naula Subscribe (free): Apple Podcasts, Google Podcasts, RSS, email Links for this episode Join the MicrobeTV Discord server Gene expression in wood ants infected with lancet fluke (Mol Ecol) Visualisation of the master manipulator in the brain of its ant host (Sci Rep) TWiP study – information and survey Become a patron of TWiP Send your questions and comments to twip@microbe.tv Music by Ronald Jenkees

TWiP solves the case about the female who traveled to Brazil and upon returning home felt movements under her scalp on the back of her head, and present another case for your solving, a man with abnormal brain MRI. Hosts: Vincent Racaniello, Daniel Griffin, and Christina Naula Guest: Eyal Leshem Subscribe (free): Apple Podcasts, Google Podcasts, RSS, email Links for this episode Join the MicrobeTV Discord server Life cycle of Dermatobia hominis (CDC) Letters read on TWiP 267 TWiP study - information and survey New Case Man in his 40s, married with 2 children, on Eliquis for a prior DVT, diet-controlled diabetes, who is admitted for evaluation of an abnormal brain MRI. He left AMA but then developed vomiting and returned. CT- Large peripherally enhancing mass lesion in the deep left cerebral hemisphere is associated with considerable vasogenic edema/infiltrative nonenhancing tumor. Mass effect results in left-to-right subfalcine herniation and entrapment of the right lateral ventricle. Findings are typical for glioblastoma. Intracranial abscess tumefactive multiple sclerosis and brain metastasis may mimic this appearance. Recommend supplemental imaging evaluation including gadolinium-enhanced MR brain. MRI- Dominant heterogeneously enhancing mass in the left basal ganglia/peri-insular region measuring 3.1 cm AP by 2.8 cm TR by 2.9 cm cc, with surrounding vasogenic edema resulting in mass effect and midline shift, as detailed above, concerning for high grade glial neoplasm versus metastasis. Additional leptomeningeal nodule in the right postcentral sulcus. Additional smaller peripherally enhancing lesion in the right lateral temporal region with suggestion of leptomeningeal component and measures approximately 0.8 x 0.8 cm, with mild surrounding vasogenic edema. They do a biopsy and pathology comes back as: – Brain tissue with extensive necrosis acute chronic inflammation, and rare microorganisms (on permanent section) -Brain, designated "left brain lesion", excision: – Brain tissue with extensive necrosis acute and chronic inflammation, reactive gliosis and occasional microorganisms Become a patron of TWiP Send your questions and comments to twip@microbe.tv

TWiP solves the case about the parasite check in summer camp, and presents a new case about a woman who traveled to Brazil and developed furuncles on the back of her head. Hosts: Vincent Racaniello, Daniel Griffin, and Christina Naula Subscribe (free): Apple Podcasts, Google Podcasts, RSS, email Links for this episode Join the MicrobeTV Discord server Hero: Francesco Redi Wikipedia: https://en.wikipedia.org/wiki/Francesco_Redi Linda Hall Library, Kansas: https://www.lindahall.org/about/news/scientist-of-the-day/francesco-redi/ Habermehl, G., (1994). Francesco Redi—Life and work, Toxicon 32 (4) https://doi.org/10.1016/0041-0101(94)90292-5. Letters read on TWiP 265 New Case From Eyal Leshem, a returning case "provider" 43 years old female who travelled to Brazil on May 2025 for a two week dance class. The dance school is located in a farm two hour drive West of Rio de Janeiro. Upon return to Israel she started feeling pricking and "movements" and under her scalp on the back of her head. She noted three non-healing furuncles on the back of her head A month after she returned movement and pricking in the back of her scalp increased, the furuncles enlarged and produced serous discharge. Several days before her ED visit she thinks an "object" dropped from the back of her scalp, but being outdoors, she could not locate the object. On physical examination she is afebrile and her vitals are normal, and on the back of her head two indurated were detected under the hair on the back of her head. Serous discharge was produced by pushing the furuncles. A non-surgical office procedure led to immediate recovery and confirmed the diagnosis. What was the parasite? What was the procedure? Become a patron of TWiP Send your questions and comments to twip@microbe.tv Music by Ronald Jenkees

TWiP solves the case of the world travelers with poppy-seed size dots embedded in their skin, then present a new case about parasite check in summer camp. Hosts: Vincent Racaniello, Daniel Griffin, and Christina Naula Subscribe (free): Apple Podcasts, Google Podcasts, RSS, email Links for this episode Join the MicrobeTV Discord server Hero: Dr Laurence Tetley Letters read on TWiP 263 New Case It is the first day of summer camp and the children are lined up for a parasite check. Some of the children have certificates that allow them to bypass the screening. Some of the parents are upset about this process commenting that this is not required by the state and report this could not be a problem for their children. One by one the children have their scalps examined and 2 of the children are asked to step to the side. The parents of these two children are contacted and told that they must address the identified concern before they can attend the camp. They are treated with a topical therapy on their hair with repeat in 1 week. The upset parents have several questions that hopefully our listeners can address. -what is this all about? -is anyone suggesting this is a hygiene issue? -what is the most sensitive way to look for this problem? -how do we know it is cured? -feel free to talk about the life cycle Become a patron of TWiP Send your questions and comments to twip@microbe.tv Music by Ronald Jenkees

TWiP solves the case of the pregnant woman from Tanzania with dehydration and 3 weeks of bloody stool, a situation that would confuse Ockam but not Dr. Hickam. Hosts: Vincent Racaniello, Daniel Griffin, and Christina Naula Subscribe (free): Apple Podcasts, Google Podcasts, RSS, email Links for this episode Join the MicrobeTV Discord server Hero: Dame Bridget Ogilvie (Interview and Wiki) Letters read on TWiP 261 New Case I feel like the back section of our book has been a bit neglected. The new PD 8th Edition is posted on our website so please download a copy and extra points to anyone who can tell us what that is on the cover. Three individuals are involved here with a rather impressive travel history. We have a mom, a daughter and a son who reach out for guidance. Initially one of them found something small dark and about the size of a poppy seed embedded in their skin. This led to a more involved investigation where they found that all three had similar findings but some of these were larger, some a bit larger, one was actually described as mobile. They all feel fine and report no skin rashes. They have a number of concerns about what these are, if they might carry disease, what to do about removing them and should there be testing or treatment. The interesting travel and exposure history. They report that just prior to this they spent a week on a remote island off the coast of Scotland with extensive hiking in tall grass and boggy areas with deer, rabbits, and lots of sheep. An Island called Harris and Lewis and then just that Saturday hiking in wooded areas around Loch Ness and in the Cairngorns. Sunday out hiking and running on Long Island and then Wednesday when these mystery objects were found they had just been hiking and going for a run in Cape Cod. They report on Cape Cod the trail they followed had a fallen tree and they had to crawl underneath it prompting this skin inspection. -lots of questions here… What might these be and how do we identify them? Is the travel history relevant? Are there any timing issues that impact what we do? Should we try to remove these and if so how? Any testing or treatment indicated? Become a patron of TWiP Send your questions and comments to twip@microbe.tv Music by Ronald Jenkees

TWiP solves the case of the man in the Malaysian city of Kucheng who presents with daily fevers and shaking chills, and serve a new clinical puzzle for you to solve. Hosts: Vincent Racaniello, Daniel Griffin, and Christina Naula Subscribe (free): Apple Podcasts, Google Podcasts, RSS, email Links for this episode Join the MicrobeTV Discord server Letters read on TWiP 259 New Case Another case from Northern Tanzania, up by the border of Kenya. 32 yo pregnant woman admitted to the hospital, dehydrated, reporting 3+ weeks of diarrhea. Second trimester, second pregnancy, reports stools are sticky and it is hard to get herself clean. She also noticed blood mixed in the stool. No fever, no chills, but she feels weak. While many in the area get their water from boreholes, rivers and rainfall she reports getting hers from a nearby river. She lives with her husband and one child who is 2 years old. She is HIV negative and reports she had been in good health otherwise. She looked tired and worn down when she arrived in the hospital but is already feeling better. Her blood work is notable for a low hemoglobin and elevated creatinine. Stool studies are sent and Ockam would be confused but Dr Hickam would know what to do. Become a patron of TWiP Send your questions and comments to twip@microbe.tv Music by Ronald Jenkees