#rickettsiae

[biology-geology-beaches-india]

The Science Research Journals of Satyendra Sunkavally, page 19.

[strigops]

old lady boris and her little white leg 🤍

she’s my oldest and largest a. vulgare and even in her advanced age is currently FULL of mancae!!! i regularly check the bellies of my isolated and hopefully healthy vulgare’s to make sure they are aren’t infected, and was pleasantly surprised to see many babies in the grand ol dame’s pouch. the do-over culture has tons of babies already and im so glad these guys have hope. i won’t know for a very long time if the whole culture is uninfected since the disease can take so long to progress to being symptomatic but i feel good about it, knock on wood. may boris and her many kids help save the florida bugs <3

[pierre-hector]

Armes biologiques : qui fait quoi ?

Par Dilyana Gaytandzhieva, journaliste d'investigation bulgare (1).

« L'unité A1266 du Pentagone et des scientifiques locaux ont collecté 40000 tiques dans 13 régions du Kazakhstan et isolé quatre bio-agents qui constituent une grave menace de bioterrorisme : virus de l'encéphalite à tiques (TBEV), virus de la fièvre hémorragique de Crimée-Congo (CCHFV) [Ébola], Rickettsia et Coxiella burnetii (l'agent causal de la fièvre Q). Ces bio-agents ont le potentiel d'être conçus pour la diffusion massive d'aérosols et utilisés comme armes biologiques. [...]

Le programme du Pentagone sur les tiques et les maladies transmises par les tiques au Kazakhstan a débuté il y a dix ans, selon l' étude publiée par la National Library of Medicine des États-Unis en 2016. “Nous disposons de nouvelles données substantielles sur une maladie grave transmise par les tiques en Asie centrale, de l'importance à la fois pour les autorités de santé publique locales et mondiales, ainsi que pour le DoD américain”, affirment les chercheurs. Tous les bio-agents qui ont été découverts dans des tiques infectées au Kazakhstan dans le cadre du programme DoD ont été étudiés comme des armes biologiques potentielles dans le passé. […]

Recherche sur les coronavirus

Un autre projet du Pentagone a étudié les coronavirus chez les chauves-souris (2015-2018). Au total, 200 échantillons de guano de chauve-souris ont été collectés dans trois grottes du Kazakhstan. Dans l'ensemble, 25 (12,5%) de tous les échantillons de guano testés étaient positifs pour les coronavirus. Cette étude a été financée par le projet de recherche biologique coopérative KZ-33 : MERS Coronaviruses : Surveillance and detection in Kazakhstan. [...] » (Dilyana Gaytandzhieva) (trad. Google)

Lire la partie concernant la peste noire à l’aide de Google Chrome (par exemple).

« L'Agence de réduction des menaces de défense (DTRA) a dépensé près de 300 millions de dollars pour deux laboratoires de biosécurité de niveau 3 (BSL3) au Kazakhstan depuis 2009 : le Laboratoire central de référence à Almaty (également connu sous le nom de Centre scientifique kazakh de quarantaine et des maladies zoonotiques (KSCQZD), et l'Institut de recherche sur les problèmes de sécurité biologique (RIBSP) à Otar, révèlent des documents du registre des contrats fédéraux des États-Unis.

DTRA a sous-traité une grande partie du travail à des entrepreneurs privés américains. AECOM Government Services a remporté un contrat de 240,4 millions de dollars pour la construction des deux laboratoires BSL 3 (2009-2016). Une autre société américaine CH2M Hill a reçu deux contrats fédéraux : un contrat de 38,4 millions de dollars pour des services scientifiques (20 août 2015 - 31 août 2020) et 17,2 millions de dollars supplémentaires pour l'ingénierie et la livraison d'équipements (31 janvier 2020 - 2 février 2023).

Ces installations américaines au Kazakhstan ne sont que deux des nombreux biolaboratoires du Pentagone dans 25 pays à travers le monde. Ils sont financés par la Defense Threat Reduction Agency (DTRA) dans le cadre d'un programme militaire de 2,1 milliards de dollars - Cooperative Biological Engagement Program (CBEP), et sont situés dans des pays de l'ex-Union soviétique tels que le Kazakhstan, la Géorgie et l'Ukraine, le Moyen-Orient, l’Asie du Sud-Est et l’Afrique.

Les laboratoires Bio-Safety Level 3 sont accessibles uniquement aux citoyens américains disposant d’une autorisation de sécurité. » (Dilyana Gaytandzhieva) (trad. Google)

‣ Dilyana Gaytandzhieva, « Pentagon Unit A1266 studies bioterrorism agents in Kazakhstan » (« L'unité A1266 du Pentagone étudie les agents de bioterrorisme au Kazakhstan »), pub. 21 juil. 2020, http://armswatch.com/pentagon-unit-a1266-studies-bioterrorism-agents-in-kazakhstan/ (cons. 21 juil. 2020). — (1) « Dilyana Gaytandzhieva est une journaliste d'investigation bulgare, correspondante au Moyen-Orient et fondatrice d'Arms Watch. Au cours des deux dernières années, elle a publié une série de rapports révélateurs sur les livraisons d'armes aux terroristes en Syrie et en Irak. Son travail actuel se concentre sur la documentation des crimes de guerre et des exportations illicites d'armes vers les zones de guerre du monde entier. – http(:)//armswatch(.)com » (trad. Google) —

[gamboagarcia]

Gracias de antemano por sus comentarios Exhorta Salud Municipal a reportar aparición de garrapatas en domicilios La aparición de garrapatas en las viviendas de los juarenses trae consigo un grave problema de salud pública, pues estos artrópodos transmiten el virus de la Rickettsia con su mordida, enfermedad que puede causar la muerte, informó Daphne Santana Fernández, directora de Salud Municipal. Ciudad Juárez, Chih .- Por ello, la funcionar... Sigue leyendo: https://www.adiario.mx/en-la-salud/exhorta-salud-municipal-a-reportar-aparicion-de-garrapatas-en-domicilios/?feed_id=163282&_unique_id=668aa8ca1d643

[adiariomx]

Reportan en la clínica 66 del IMSS el deceso de menor de 4 años a causa de la morderá de una garrapata. Ciudad Juárez, Chih (ADN/Arturo Hernández) - ...

[jornale]

#febremaculosa #carrapato #saude #Rickettsia #brasil #news #noticias

[ceilidho]

fear of god

There's someone outside the spacecraft. You don't remember them being part of the crew. Part 7 masterlist

-

And now that the permafrost has thawed, the carcasses buried below have started to warm and the anthrax spores in their ribs have begun to twitch. 

To say that you are on edge would be an understatement. Your muscles ache from being tensed for so long in the supine position, but you remain that way until the day cycle returns and the ship hums back to life, the thought of sleep unfathomable. Synapses firing in your brain keep you from sleeping soundly. Or at all, for that matter. By morning, you’re exhausted, eyes burning from lack of sleep and head pounding something fierce. 

Old questions are compounded by new ones. Ones such as, is what you’re experiencing real? Can you trust what’s in front of your eyes? Are your senses lying to you? How can you be sure of anything happening to you right now? What can you use as a yardstick to measure reality? 

The most worrying question being: did you make a mistake? 

You review the evidence again, starting from the top. A man suspended in the middle of space with no other spaceship for millions of miles nearby. You didn’t imagine that. Unless your mind has deteriorated to such an extent that you now reside entirely within a made up universe where a stranger—seen and acknowledged by your colleagues—boarded and took residence on your ship, which is a thought too horrified to contemplate for very long, then you have to believe that nothing you experienced over the last several days was just in your head. 

Which means that over the period of a week, a man hovered in space right outside the still moving ship, somehow following its flight trajectory, and no one other than you noticed his presence. Conspicuously absent from all perimeter scans and observational points. Disappearing from sight, in fact, when another crew member tried looking for him. 

Everything points to him being a figment of your imagination, but what does it say now that the people around you are able to see him as well? And what does it say that they seem completely unconcerned with having found him at all?

Your stomach rumbles and you climb out of bed. 

You creep tentatively down the hall towards the mess, sensitive in a whole new way to your surroundings. The corridor remains empty and quiet save for your trembling breaths. A deep, thrumming hum follows you through the ship. 

Nikolai’s already there when you enter the mess, and you catch him in a good mood, which is like saying you caught Rickettsia where typhus was found present. Which is to say, unsurprising. 

“Morning, doctor,” he booms from across the mess. “Sleep well?”

You hum instead of giving a straight answer. “You?”

“Best sleep in months. We should rescue people more often. Makes life more interesting, yeah?”

Again you hum instead of responding verbally. 

It makes life more interesting or it makes life a tragic crawl to oblivion. This doesn’t feel like some Greek tragedy, but then again the people in it are never privy to their genre. You don’t have the luxury of knowing what’ll happen next until it happens, until the moment is already beyond you and you’re forced to stare back in horror at all the goosestepping you did to reach this point. 

You shake your head to dispel those thoughts. 

Breakfast is another mundane affair. Some days you miss buttered toast so bad that you teeter on the edge of bursting into tears. A deep yearning for the familiar, for home. It sneaks up on you when you least and most expect it, waiting for you to let your guard down. 

Your whole body tenses up when the mess door slides open with a gentle hiss and you hear Gaz’s voice. Again, a wave of nostalgia washes over you, an ache felt deep in your pelvic bone like staring out of a fogged up window and watching the world pass you by. 

Real coffee in real cafes; sitting at the back of the bus on a cold day, tucked into an oversized scarf and drifting off, head bouncing with every little bump; the crunchy-cream spoonful of a crème brûlée; running your fingers over glaucous leaves in the garden behind your late professor’s house, the waxy coating rubbing off onto the pads of your fingers; and then a man’s rich, deep laughter again—

Your fingers slip under the table to pinch your outer thigh and the spell breaks, the pain grounding you. 

“Morning, little castaway,” Nikolai booms, leaning back in his chair and raising a hand in greeting. “Finally rested after your journey?”

“Can’t complain,” Gaz says while making himself a coffee with the instant crystals. 

When the coffee is finally ready, Gaz wanders casually over to the table, stopping when he reaches your side. You put off looking up at him until the tension in the room reaches critical mass. 

Then you finally look up in acknowledgement and find him smiling placidly down at you. He looks rested, no sign of stress or bags under his eyes or so much as a hair out of place. You’d never suspect that he just spent the last several days stranded in the middle of space. 

“Good morning, doctor,” he greets.

What is it about the cadence of his voice that scratches the ear just so? There’s something to it, a layering behind his words that you can’t make out. 

“Morning,” you reply, voice cracking after the first syllable. You cough and clear your throat. 

He joins the two of you at the communal table, pulling out a chair to sit right next to you, humming and nodding when Nikolai lets him know where to find the ration packets for breakfast. He doesn’t make a move to go grab something to eat. 

“Not a breakfast person?” Nikolai asks.

A smile. “I need to work up more of an appetite.”

His words fill you with such cold dread that you can’t even look over at him. Frozen in place, spoon buried in your bowl of oatmeal in front of you. Then embarrassment washes over you when you play his words back in your head and realize how normal they sound. 

“What’s on the docket for today?” you ask to change the subject.

“Same shit as always,” Nikolai sighs, resting both elbows on the table and sinking his head into his palms. He dips his head forward enough to run his hands through his hair before straightening up again. “Farah has some ideas for how to approach the situation, but…I have my doubts. Not worth boring you all with details. Either problem will be resolved or not. Same shit, different day.”

“I’m sorry, but is something on the ship broken? Is there a problem?” Gaz’s concern seems so genuine that for a second you allow yourself to get swept up in the illusion that he has no idea what’s wrong with the ship. 

“Autonomous navigation is broken,” Nikolai explains, rolling his eyes, frustration oozing from his pores. “It was on the fritz when we passed Mars, but now it’s dead. Kaputt. Thought at first that maybe it was inertial measurement unit that was malfunctioning, but fixing that changed nothing. Then we thought: maybe something is wrong with star tracker, but code looks good, so can’t be that. Lots of time wasted and still nothing is working; it’s a very troubling problem.” 

“Do you mind if I take a look at it?” Gaz asks. “I was the technical engineer on my previous ship. It might help to have someone come at it with fresh eyes.”

Nikolai studies him, the moment of scrutiny breaking his usual jocularity. Then he shrugs. “Why not? But if you break anything, I will personally toss you out of the airlock.” 

Gaz smiles wide. “Sounds fair. ”

‘Technical engineer’ indeed. You scoff in your head, unsure of your own scepticism but committed to it because everything about the situation just feels all too convenient. 

Much bites when it feels threatened; you know this and you have to choose not to act on it.

Oatmeal mostly done, you scoot your chair back and get up, eager to head to your station. 

“See you guys in an hour for morning briefing,” you say to the two of them, tossing your bowl haphazardly into the dishwasher. 

“Mind if I walk with you?” Gaz asks, also rising to his feet. 

Your heart jumps. “Why?” 

Something in your tone must give you away because even Nikolai glances up, furry brows pulling together concernedly. Careful now. You give yourself away when you speak without thinking first. 

Gaz smiles with all his teeth. “It’s on my way. The commander wanted me to pass by after breakfast.”

Too much time passes for you to cover up your faux pas with an excuse. Better just to swallow your pride instead. 

“Sure.”

You’re so stiff on the walk to the medical unit that your low back aches, the nerves likely inflamed. An old injury flaring up from stress. You’ll have to remember to roll out your yoga mat and stretch later, some cat and cow to loosen up your back.

“It’s bigger than I thought,” Gaz observes casually. “From outside, you don’t get the same perspective, but even for an old ship, there’s quite a bit to it.”

Hearing him speak so frankly about watching the ship from the outside sends a chill down your spine.

What’s the use in telling you this? You can only speculate. Though his tone remains unambiguously light, eyes scanning the paneled interior walls and the incandescent light strips overhead running parallel to the floor, there’s a veiled weight there. Something almost taunting. 

“Is it?” you whisper, compelled to answer for reasons beyond you. “Is that…is that something you thought about a lot?”

“No,” he answers, quite simply. “I knew I’d get to see for myself eventually.”

Sometimes, in the privacy of your mind, you think about how some of the Earth's oldest trees are kept secret from the rest of civilization. You crave that kind of furtiveness now, wish you could burrow that far deep and remain hidden. 

You wish you weren’t plagued by the knowledge that a static body in space couldn’t possibly keep up with a spacecraft in constant motion for several days on end. You want to go back to not knowing anything at all.

But before you are precious hours of solitude, so you hold your tongue until you reach the midway point in the ship where the corridors split and your paths diverge. 

Just as you’re about to part, Gaz stops and looks down at you. “By the way, doctor, you haven’t evaluated me yet. When should I come by?”

“Evaluate?”

He cocks an eyebrow. “Make sure I’m not sick or infected with anything. Isn’t that part of your job?”

It’s said in earnest but it feels like a barb. A sharp thorn in your side pricking you again, telling you that you’re not pulling your weight. That you’re taking up space and not contributing to the mission.

“Maybe, um…” You clear your throat. “Whenever you have time. Tomorrow.”

“Tomorrow,” Gaz repeats, eyelids narrowing with his smile until just the darks of his eyes are visible, the cornea all but gone. “Sounds like a plan.”

Again, you can feel it calling you to him. Whatever it is. Thoughts laggardly filling your head, sticky like sap or syrup. His face is nice to gaze on, they say, nicer still to touch. Your hands itch to reach up and cup his cheeks though a louder voice in your head reminds you of how improper that would be. 

You take a step back and the urge falls away like rain.

And then he’s gone, continuing down the corridor towards the front of the ship without another word. 

You wonder if there’s something wrong with you for not insisting on examining Gaz in the medbay as soon as possible. Even if you were to take him at face value and ignore all the other red flags warning you away from him, you’d be remiss not to check his vitals and bloodwork. 

Tomorrow you will. You’ll be braver tomorrow. 

The second the door slides open and you take a step forward, you can tell that someone was in the medbay earlier. Your nose twitches, like a smell you know but can’t name. Right on the tip of your tongue; hungering for the word that eludes you for so long that you wonder whether it even exists or if your brain has tricked you into remembering something you’ve never encountered before. Presque vu; the wallflower step-sister of epiphany. 

You take another step into the room and start when the door slides shut behind you automatically. When you look around the room, nothing looks taken or moved. Even your microscope is still out on the table from the day before. 

A deep inhale just leaves you more frustrated. The only smell in the room is that of formaldehyde and antiseptic, but still the feeling impresses itself upon you, despite the lack of evidence. Someone was here. You’re sure of it. It’s an uncanny feeling, like knowing that someone’s eyes are on you. 

You’ve heard of conditions causing one to detect smells that aren’t really present—phantosmia, sometimes caused by nasal polyps or strokes, but neither of those fit your circumstances. Nothing your mind conjures up as a probable cause fits right. 

Pinching your nose works to an extent, but it’s not a sustainable solution; you can’t go hours on end with one hand clamped over your face. It cuts the strange effect the scent has on your mind though, concrete evidence that what you’ve been experiencing is in large part an olfactory phenomenon. 

In the en-suite bathroom, you riffle through the medicine cabinet one-handed, wincing when you knock over a bottle of cough medicine and send it tumbling to the floor. You rummage around until you find what you’re looking for in a little blue container still nestled under the cinching straps lining the back of the medicine cabinet. 

Unscrew and uncap to a waxy, off-white jelly. You slather a thick layer of petroleum jelly under your nose, so thick that a glob lodges in your left nostril and you nearly sneeze it out. It does the trick though. Mutes the scent somehow; turns the dial all the way back down to zero so you can breathe with ease again. Think clearly again. 

You step back into the main room. When you look back around the medical unit, again you notice that not a single thing looks out of place. If someone had been here before you, there would be signs—things misplaced or forgotten out on one of the tables or on the exam bed in the middle of the room. This is the only room on the ship entirely under your supervision and dominion; you know where each piece of equipment is stored and how every inch of the room should look after you’ve put everything away. 

But the room looks fine. Untouched. 

Your better judgment tells you to just let it go. 

Touching your palms to your pants, you find them drenched in sweat. The body knows when there's something amiss. 

You observe and take note.

[tanadrin]

some absolute nerds named a proposed subgroup of the rickettsia cellular parasites (from which mitochondria are suspected to have evolved) "midichloriaceae"

[valentineblacker]

Let's hear it for the obligate intercellular parasite, Mitochondria! I have a lot to say about this!

[flyonthewallmedstudent]

Q Fever

Aka, Query fever. What a weird name for a disease. Imagine telling people that's what you got.

in the 30s-40s, an Australian pathologist in QLD/Brisbane, came across an outbreak of the same or similar illness among abbatoir or slaughterhouse workers.

At the time, he called the disease "Q" fever or query as a temporary name until the pathogen could be identified. Unfortunately it stuck.

decades later, now nobel prize winner and virologist, MacFarlane Burnett isolated and identified the microbe responsible. I think this discovery contributed to his prize. i forget already.

Microbe responsible: Coxiella burnetti. Named for Burnett and HR Cox, the American bacteriologist who found the genus Coxiella where C burnetti falls under.

Initially they felt it was related to Rickettsia, responsible for Rocky Mountain Spotted Fever, but as science progressed, this was disproven.

Now for a Case Report

A 55 yo Italian man with a history of aortic valve replacement was diagnosed with pyrexia of unknown origin twice. Further signs included myalgias/splenomegaly/night sweats. The 2nd time he was admitted for PUO he deteriorated rather dramatically and was put on meropenem and teicoplanin.

A host of organisms was tested for on serological testing based on the man's travel and epidemiological history, all negative. Even a rheumatological panel was done, also less revealing. He also had a history of MGUS (a haem disoder), which is kind of a red herring here.

Cultures were negative, no vegetations were seen on a TTE - so they did consider IE. Which is an important differential for PUO.

Eventually a PET-CT was done (often favoured when investigations do not yield much for a sick patient with fevers), finally revealing a focus of infectious on his ascending aorta, where he'd also had previous surgery done. And in a round about way, they also further identified Coxiella Burnetti. He was treated doxycycline and hydroxychloroquine. As it's so rare in Italy, it wasn't really considered even though he mentioned rural travel.

Bottomline: Q Fever is an important consideration in the work up for culture negative IE. Further to this, always consider IE in the differentials for PUO particularly if they're at increased risk for IE (prosthetic valves, damaged valves, select congenital heart issues, previous IE). IE can present with night sweats, fevers, weight loss and splenomegaly. It can be insidious and chronic in nature. other risk factors can be more suggestive as we'll get into below.

Causative organism

Coxiella burnetti, it's a zoonoses - i.e. transmissible from animals. Special powers: very tough/hardy, can survive extreme environments (high temps and UV light etc.) over prolonged periods and is resistant to many common disinfectants/surface cleaners.

It's an intracellular pathogen and gram negative coccobacilli (PINK!)

name coccobaccili reminds me of cocopuffs.

it's mainly associated with farm animals, which the CDC so wholesomely displays on its website on Q fever (wtf).

goats, sheep, cattle typically (but many other animals, even birds, dogs and horses can be reservoirs)

in particular bodily fluids - amniotic fluid, placenta, faeces/urine, milk etc.

you can get it through unpasteurized milk and through inhaling it if it lands on dust in the area

ever visit a farm or petting zoo lately? OMG WASH YOU HANDS.

That said, it's typically inhaled in inorganic dust. You inhale it, it goes to the lungs, and then the bloodstream.

Increased risk for Coxiella burnetti (What to take on history of exposures and when to strongly consider it)

live on a farm or near one

exposure to a farm

work as a vet on a farm

farm worker, dairy workers, researchers on these animals/facilities

slaughterhouse/abbatoir

Also from CDC:

Clinical presentation

Most won't get sick after exposure and remain asymptomatic, a very small minority does. even though it is highly infectious.

incubation time is 2-3 weeks (consider this time in your history of exposure, did they work on the farm 2-3 weeks ago as opposed to yesterday).

Nonspecific acute infectious symptoms:

nonspecific systemic fevers/malaise/arthralgias/myalgias--> key is high fevers though and can be associated with headache and photophobia.

non specific GI - N/V/diarrhoea

respiratory ones - SOB or cough, consider it as atypical cause of community acquired pneumonia.

rare: hepatitis and jaundice (granulomatous) or encephalitis with neurological complications such as demyelinating disease or CN palsies, also haemolytic anaemia and HLH (yikes)

really it's the history of exposure that will lead you down the garden path to Q fever.

Chronic Q fever is perhaps worse, and can present as culture negative IE/PUO. Months/years later, as B symptoms as above above + LOW/LOA, night sweats. More likely to occur if you are predisposed for IE as above, have a weakened immune system for any reason, including pregnancy.

Chronic Q fever has a mortality of 10% if left untreated. About <5% of those with acute Q fever develop this if left untreated. Speculation is that it's more of an autoimmune process or abnormal immunological response to the bacteria.

To be honest, most who walk in the door with community acquired pneumonia get treated empirically for atypicals anyway, (standard course of doxycycline), so we hardly really ponder the question of Q fever in every patient. But if they present chronically and did not have atypical cover at the onset of acute symptoms, then it's something important to consider.

Other important conditions - can cause complications in pregnant women and 20% will get post Q fever syndrome. like chronic fatigue.

investigations

Serology! nice and easy. Look for IgG antibodies in the chronic presentation. Or PCR. Down side to serology - can take 2-3 days for the body to make said antibodies to the bacteria for detection. PCR can be done on any fluids/tissue sent.

Cultures useless, hence it fall under the umbrella of culture negative (hard to grow outside a host cell, it is an obligate intracellular pathogen).

Other hints on bloods (as serology/PCR takes time to return) - elevated or low platelet's, transaminitis with normal bili, opacities in CXR with hilar lymphadenopathy, CSF will show raised protein levels if done when encephalitis is suspected.

imaging can also support the diagnosis.. as illustrated by the case report.

Treatment

Acute disease - as standard for atypical bugs, doxycycline 100 mg BD for 14 days. Alternatives - TMP SMX or Clarithromycin.

Chronic Q fever or IE:

native valves: doxycycline and hydroxychloroquine (200 TDS) for 18 months

prosthetic: same but 24 months

why hydroxy: enhances the action of doxycycline (increases the pH of the phagolysosome)

Follow-up: look for 4 fold decrease in IGG

Sources:

CDC

Stat Pearls

Wiki as linked above

[theqhreator42]

I think Rickettsia wrote its own Wikipedia article

Some Rickettsia species are pathogens of medical and veterinary interest, but many Rickettsia are non-pathogenic to vertebrates, including humans, and infect only arthropods ... Many Rickettsia species are thus arthropod-specific symbionts, but are often confused with pathogenic Rickettsia (especially in medical literature), showing that the current view in rickettsiology has a strong anthropocentric bias.

[mleprae]

🦠 lymes! the stupid tick disease </3

Diseases caused by insect vectors, also very bad at it.. 😔

Im willing to bet that its a rickettsia behind it. wolbachia, even. always a dumb rickettsia at the scene of the crime when theres bugs involved!!!!

[nerdgirlnarrates]

Doxycycline: the only tetracycline in this tournament, doxy works by binding the ribosomal 30S subunit, inhibiting initiation of translation. Doxy has a crazy resume: it's used to treat skin infections, STIs, Lyme disease, acne, Rickettsia, and on and on. It can even be used for malaria prophylaxis. As with other tetracyclines, it has the rather odd risk of tooth discoloration. This discoloration is due to tetracyclines' chelation with calcium and incorporation into calcifying tissues such as teeth or bone (does this mean it discolors your bones too??)

Clofazimine: clofazimine is an odd drug. It is exclusively used as part of the therapy for lepromatous leprosy (not even tuberculoid leprosy), though there is evidence it could be effective in treating MAC pneumonia in combination with a macrolide and ethambutol. It is a phenazine dye, and it works by binding to bacterial DNA and preventing transcription. A match to doxycycline, clofazimine's oral formulation frequently causes red skin pigmentation.

Which hyper-pigmenter deserves to win this round?

Vote for the best antibiotic

[centers-for-disease-control]

HI TRICK OR TREAT

Rickettsia rickettsii

[crevicedwelling]

what are the biggest challenges you face keeping bugs as pets? i keep plants, a friend of mine keeps fish. it seems to me that fungi, algae and parasites are inevitable everywhere on planet earth. do these ever cause problems?

no algae since everything is in the dark, parasites stop being an issue if the animals are captive bred and fed proper food, and the only fungi that mess with my bugs are occasional molds and mushrooms that make the substrate gross. (part of why I like dirt over water!)

“porcelain disease” (not actually the aquatic fungal crayfish one but symptoms look the same) has been an issue for me, Rickettsia bacteria that infects isopods and kills them although they usually look normal at a glance. I’ve been sold infected isopods and collected them myself, and while the bacteria can be persistent it typically only spreads through cannibalism and it’s easy to control by quarantining and separating newborn isopods from the infected generations.

porcelain is pretty much the only issue I have with that sort of thing! my springtail and mite crews control mold, rot, parasitic mites, and fungus gnats, and all my feeders (roaches, beetle larvae) are bred by me, so I don’t worry about parasites.

maintaining humidity is a big issue with many inverts, and it takes some practice and good watering to figure out how to maintain a humidity and ventilation balance that suits a species. substrate composition is a minor issue but cocofiber can be ingested by centipedes and cause impactions that can kill them.

[o-craven-canto]

Again on the subjects of parasites.

Meet Wolbachia.

These handsome fellows are three individuals of Wolbachia, happily residing in their place of choice -- an insect cell. Wolbachia is a bacterium, loosely related to Rickettsia, whom we have to thank for typhus and other louse- or tick-borne diseases. As it happens, they are also relatives of those ancient bacteria that took residence in our own cells and became our faithful mitochondria.

You don’t have to fear ever being infected by Wolbachia: it does not enter vertebrates. Arthropods, however, are not so lucky. (Nor are their close relatives, Nematode worms.) After all, Arthropods make up >90% of all (known!) animal species, and 40% of all animal biomass. A feast for parasites!

Now, Wolbachia has done one better than most pathogens. Not content with horizontal transmission (i.e., from individual to nearby individual), it has graduated to vertical transmission (i.e., from parent to child). The way Wolbachia accomplishes this is quite simple: it hides away in eggs.

Every time its host lays an egg, the parasitic bacterium slips in some copies of itself. Every time a host cell divides, the bacteria divide with it. Every time a host individual reproduces, the bacteria reproduce with it. Every time a host population moves away... well, you can put several sections of the Nematode or Arthropod phylogenetic trees right next to the phylogenetic tree of the Wolbachia they host, and you will see they have the same shape, branching and splitting in the same points and with the same pattern. Host and parasite evolve together.

Alas, this trick works only with eggs -- sperm cells are far too small to contain clandestine bacteria. Which means a full half of all hosts are useless for Wolbachia to propagate its own genes! Our fair bacterium wants (in the same sense that water “wants” to flow to the sea, or that fire “wants” to consume its fuel) to be hosted only by females.

How to accomplish that? Over millions of years (and billions of generations) of trial and error, Wolbachia found four ways.

(source: Werren et al. 2008)

Feminization. Straightforward enough, and yet the rarest. If you are in a male, and want to be in a female, why not make it so? In some butterflies and true bugs, and most commonly in wood lice, Wolbachia works its magic -- during male development, the bacterium interferes with the hormon signals of its host (remember Sacculina?) to turn it into a fertile female.

Parthenogenesis. In some thrips, wasps, and mites, Wolbachia has so perfected its biochemical manipulation of its host that it can grant its female carriers the ability to reproduce asexually. (It’s not so uncommon, among insects.) A parthenogenetic female will, with few exceptions, generate only females, so all will be able to carry the parasite.

Male killing. Simple but paradoxical. Some Wolbachia species, mostly carried by flies, beetle, butterflies, and funky little pseudoscorpions, simply kill their host before hatching whenever they find themselves inside a male. You might think it absurd -- is it not suicide? It is. But every Wolbachia cell is an exact clone of all the ones surrounding it (more so than most pathogens, thanks to its reliance on vertical transmission). So if you, a male-carried bacterium, happen to contain a male-killing gene, then your female-carried kin, which being your clones will also carry the male-killing gene, will enjoy more resources to produce more infected eggs. So the male-killing gene prospers. You will die; but your genes won’t care.

Cytoplasmic incompatibility. The most sophisticate, and yet the most widespread, known in many orders of insects as well as mites and wood lice. In a partially infected population, four possible pairings may occur, as both the female and the male can each be infected or not. As long as the female is infected, Wolbachia carries on, regardless of the male’s status. If neither party is infected, the bacterium is powerless. But what happens when the male is infected, and the female is not? Well, then Wolbachia makes sure to kill its host’s children (or at least some). Over and over, until the male happens to mate with an infected female -- and then he will find he can have an offspring at last. What the parasite actually does is modify the sperm of an infected male so that its chromosomes will be misaligned during the fertilized egg’s first division. This always results in aborted embryos, unless the egg is modified in the same way by resident parasites, in which case development proceeds as intended. Of course the bacteria carried by the male will not reproduce in any case: they are not in the sperm. But their sibling-clones in their host’s partner will, as uninfected females find themselves slowly dying out, and that’s enough.

Strangely enough, Wolbachia has taken a different route altogether in some Nematodes. No longer a parasite, for them it’s a mutualist, cooperating with its host to the benefit of both. Unfortunately for us, it does so mostly in Filarioidea, which includes such charming fellows as heartworms, eye worms, and the agent of elephantiasis. And they definitely attack vertebrates. Happily, though, this gives us an avenue of counterattack: killing Wolbachia with antibiotics effectively kills the filaria as well.

There are plans to weaponize Wolbachia against malaria-carrying mosquitoes and other disease-carrying insects. Perhaps it can make itself useful to us, too.