#Infectious Disease

[gumjrop]

This year’s flu shot will be missing a strain of influenza it’s protected against for more than a decade.

That’s because there have been no confirmed flu cases caused by the Influenza B/Yamagata lineage since spring 2020. And the Food and Drug Administration decided this year that the strain now poses little to no threat to human health.

Scientists have concluded that widespread physical distancing and masking practiced during the early days of COVID-19 appear to have pushed B/Yamagata into oblivion.

This surprised many who study influenza, as it would be the first documented instance of a virus going extinct due to changes in human behavior, said Dr. Rebecca Wurtz, an infectious disease physician and epidemiologist at the University of Minnesota School of Public Health.

“It is such an interesting and unique story,” Wurtz said, adding that if it were not for COVID, B/Yamagata would still be circulating.

One reason COVID mitigation efforts were so effective at eliminating B/Yamagata is there was already a fair amount of immunity in the population against this strain of flu, which was also circulating at a lower level, said Dr. Kawsar Talaat, an infectious disease physician at Johns Hopkins Bloomberg School of Public Health.

In contrast, SARS-CoV-2 was a brand new virus that no one had encountered before; therefore, masking and isolation only slowed its transmission, but did not stop it.

The absence of B/Yamagata won’t change the experience of getting this year’s flu shot, which the Centers for Disease Control and Prevention recommends to everyone over 6 months old. And unvaccinated people are no less likely to get the flu, as B/Victoria and two influenza A lineages are still circulating widely and making people sick. Talaat said the disappearance of B/Yamagata doesn’t appear to have lessened the overall burden of flu, noting that the level of illness that can be attributed to any strain varies from year to year.

The CDC estimates that between 12,000 and 51,000 people die every year from influenza.

However, the manufacturing process is simplified now that the vaccine is trivalent — designed to protect against three flu viruses — instead of quadrivalent, protecting against four. That change allows more doses to be produced, said Talaat.

Ultimately, the costs of continuing to include protection against B/Yamagata in the flu shot outweigh its benefits, said Talaat.

"If you include a strain for which you don't think anybody's going to get infected into a vaccine, there are some potential risks and no potential benefits," she said. "Even though the risks might be infinitesimal, the benefits are also infinitesimal."

Scientists and public health experts have discussed for the past couple years whether to pull B/Yamagata from the flu vaccine or wait for a possible reemergence, said Kevin R. McCarthy, an assistant professor at the University of Pittsburgh's Center for Vaccine Research. But McCarthy agrees that continuing to vaccinate people against B/Yamagata does not benefit public health.

Additionally, there is a slight chance of B/Yamagata accidentally infecting the workers who manufacture the flu vaccine. The viruses, grown in eggs, are inactivated before being put into the shots: You cannot get influenza from the flu shot. But worker exposure to live B/Yamagata might occur before it's rendered harmless.

That hypothetically could lead to a reintroduction of a virus that populations have waning immunity to because B/Yamagata is no longer making people sick. While that risk is very low, McCarthy said it doesn’t make sense to produce thousands of gallons of a likely extinct virus.

It is possible that B/Yamagata continues to exist in pockets of the world that have less comprehensive flu surveillance. However, scientists aren’t worried that it is hiding in animals because humans are the only host population for B lineage flu viruses.

Scientists determined that B/Yamagata disappeared in a relatively short period of time, and this in and of itself is a success, said McCarthy. That required collaboration and data sharing from people all over the world, including countries that the U.S. has more tenuous diplomatic relationships with, like China and Russia.

“I think the fact that we can do that shows that we can get some things right,” he said.

Sarah Boden is an independent health and science journalist based in Pittsburgh.

[macgyvermedical]

Incubation Periods List

Hi all!

The following is a list of incubation periods for various infectious diseases for all your writing needs. An incubation period is the amount of time between exposure to an infectious agent (bacteria, virus, protozoa or prion) and the person having the first symptoms of the resulting illness. Knowing this is helpful in creating a timeline for your story.

Anthrax: Incubation period of 1-60 days

Avian Flu: Incubation period 3-9 days

Botulism: Incubation period 12-72 hours

Chikungunya: Incubation period 3-7 days

Chlamydia: incubation period 7-21 days

COVID-19: Incubation period 5-10 days

Creutzfeldt-Jacob Disease: Incubation period 10-20 years

Dengue: Incubation period 5-7 days

Diphtheria: Incubation period 2-5 days

Ebola: Incubation period 2-21 days

Hantavirus: incubation period 1-8 weeks

Hepatitis A: incubation period about 28 days

Herpes: Incubation period 2-12 days

Herpes Zoster/Varicella (Chickenpox): Incubation period 14-16 days

Herpes Zoster (Shingles): Incubation period- technically none, as this is a reactivation of the virus that causes chickenpox

HIB: Incubation period 2-10 days

HIV: Incubation period 1-6 weeks to prodrome, approximately 10 years to AIDS

Influenza: Incubation period 1-4 days

Legionnaires Disease: Incubation period 5-6 days

Leprosy: Incubation period 9 months to 20 years

Lyme Disease: Incubation period 3-30 days

Malaria: Incubation period 7-30 days

Measles: Incubation period 10-12 days

Meningitis, Bacterial: Incubation period 2-10 days

Meningitis, Viral: Incubation period 3-10 days

Monkeypox: Incubation period 1-2 weeks

Mumps: Incubation period 16-18 days

Norovirus: Incubation period 12-48 hours

Pertussis: Incubation period 7-10 days

Plague: Incubation period 2-8 days

Pneumococcal Pneumonia: Incubation period 1-3 days

Polio: Incubation period 7-10 days

Q-Fever: Incubation period 2-3 weeks

Rabies: Incubation period 20-90 days

RSV: Incubation period 4-6 days

Smallpox: Incubation period 7-17 days

Syphilis: Incubation period 10-90 days

Tetanus: Incubation period 3-21 days

Tuberculosis: Incubation period 2-10 days

Typhoid: Incubation period 6-30 days

Typhus: Incubation period 1-2 weeks

West Nile Virus: Incubation period 2-6 days

Yellow Fever: Incubation period 3-6 days

Zika: Incubation period 3-14 days

[tomorrowusa]

Dr. Anthony Fauci voluntarily testified before a House committee and debunked MAGA Republican conspiracy theories regarding the COVID-19 pandemic.

While Donald Trump and his lickspittles were telling Americans to drink bleach, take useless malaria pills, stick ultraviolet lights up their butts, and eat horse paste, Dr. Fauci headed an effort to develop vaccines for COVID-19.

A reminder to people with short memories who view the Trump administration as some sort of bucolic paradise: The last quarter of that administration included the worst government response to an infectious disease outbreak since 1920. Trumpsters who want us to ignore Trump's horribly botched response to the pandemic are like cruise-liner enthusiasts who want us to ignore the last 2% of the voyage of the Titanic.

Economic activity ground to a halt in 2020 as the US slid into a recession. I took this picture of a sign at a dollar store which had been completely closed for almost two months.

The whole Trump clan was disdainful of the sacrifices hundreds of millions of Americans were making.

Why has the U.S. COVID-19 response been so bad? Jared Kushner, Vanity Fair suggests.

At Times Square Jared and Ivanka's contemptuousness was made into an ad before Election Day.

If you are looking for the Original Sin of Trump's pandemic response, it was on January 22nd when he basically told CNBC's Joe Kernen that COVID-19 was nothing to worry about.

Of course it wasn't "just fine".

Trump did not declare a state of emergency for seven weeks. That gave the virus plenty of time for it to spread throughout the US.

Republicans know that their Dear Leader totally mishandled the pandemic response. That's why they repeatedly try to make Dr. Fauci a type of scapegoat for Trump's horrendous incompetence. Dr. Fauci has spent his entire career fighting disease. Donald Trump has spent his entire career narcissistically promoting himself.

Harry Truman had a sign on his desk saying: "The Buck Stops Here!" If Trump had a sign on his Oval Office desk (which he seldom used except for photo ops) it would be: "It's Everybody's Fault But Mine!"

Don't be hesitant to remind people of how awful 2020 was. And point the finger of blame at the orange blob who was responsible for the catastrophe.

[heardatmedschool]

“If you ever prescribe an aminoglycoside, and the patient doesn’t come back complaining because it fucked up their digestion, it’s because they didn’t take it.”

[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

[howgaytobequeer]

Sometimes I think about that conversation I had in some breakroom somewhere that went something like:

Co-Worker: Man. Wouldn't it suck if there was a disease where you shit yourself to death? Me: ...There is. It's called cholera. Lots of people die of it every year.

And he was gobsmacked.

[grison-in-space]

Grudgingly I had to give up dicking around on the Internet and go do some house cleaning. I'm listening to Mary Roach tell me about cholera dynamics when I remember, and I want to tell Tumblr—

Did you know that the same specialist predator/prey population dynamics over time that you usually see described in terms of Canadian lynx and snowshoe hare also apply perfectly well to Vibrio cholerae and its most common bacteriophage?

And that this is a major factor in why pathogenic cholera outbreaks — caused mostly by only one lineage of V. cholerae bacteria — eventually fade even if the population isn't wholly infected by cholera or wiped out by it?

The world is a wild and fascinating place.

[vizthedatum]

The new 2024-2025 COVID-19 vaccine (USA) is out. It might not be free after this month for uninsured adults (?), and it may not account for further trending variants, BUT YOU SHOULD STILL GET IT.

Hi, y'all! I published a new Substack article because:

The updated COVID-19 vaccine for the 2024-2025 season is now available as of August 22, 2024.

And I have thoughts!

An excerpt from this article:

"The CDC advises that all adults receive this vaccine. The CDC recommends that everyone over six months of age receive this updated vaccine, regardless of previous vaccination status, unless they have contracted COVID-19 in the last three months.

This new vaccine will _allegedly_ remain covered under the no-cost vaccination program, the Bridge Access Program, until the end of next week. (I say “allegedly” because I don’t know.)

But you should call your pharmacy and check!

(I personally booked a COVID-19 vaccine appointment at my local CVS for August 28, 2024. I called the pharmacist earlier today to see if it would be covered under my insurance (UPMC Health Plan provided by my employer, University of Pittsburgh) or the Bridge Access Program). They told me the shipment has yet to arrive at their location, but they think it will be before my appointment and will be covered by either one. However, they can only definitively tell me once they get the shipment.)"

[lindahall]

Carlos Chagas – Scientist of the Day

Carlos Chagas, a Brazilian clinical physician and microbiologist, died Nov. 8, 1934, at the age of 55. 

read more...

[chaptertwo-thepacnw]

The Last of the Famous International Playboys |2024| continuing...

[teachingrounds]

Q. When is a follow-up chest x-ray indicated after treatment for pneumonia?

A. Get AP and lateral chest xrays if the patient hasn't improved after 48-72 on the appropriate antibiotics, or in 4-6 weeks if there is recurrent pneumonia in the same location or complications such as abscess or empyema. Otherwise, no need for a "test of cure." Patients at risk of lung cancer due to smoking history should have targeted screening. Image of pleural effusion by Ian Bickle (Radiopaedia).

[kuroshipped]

Hey guys ALERT! im leaving for florida on friday and um you may be aware that pesky mod black has been on vacation so i was taking over bt UM! yah i have to pack and stuff so there might not be a weekly this week and if there is one please forgive me it might be like. just doodle dump or something😓unless she cook but me i do not want to stress her since i have more free time

but i think i can start cooking today and tomorrow cause i have to lock in and pack thursday night mostlyu

Tabby im coming tabby watch out tabby ima see you tabby ima equius up this nepeta....🐱‍👤 @rabbitsdontstarve WATCH OUT!

[gumjrop]

Pediatric pneumonia cases requiring hospitalization are up 30% in Central Virginia.

While not a cause for panic, it does call for caution.

Christopher Doern, M.D., director of microbiology at VCU Health, said the initial investigations suggest that this rise in hospitalizations may be because of an increase in rhinovirus and enterovirus.

“The last time we saw this phenomenon was in 2014 during the EVD68 outbreak,” Doern said. “I don't have any speculation as to why this is only being observed in Central Virginia and would be surprised if it doesn't soon disseminate to the rest of the region and beyond.”

David Marcello, M.D., chief of pediatric hospital medicine, answers some key questions about the spike in pneumonia cases and the type of care being provided at Children’s Hospital of Richmond at VCU.

What might be causing this current rise in pediatric pneumonia?

In addition to increased Mycoplasma infections (atypical bacterial pneumonia), community acquired bacterial infections, we’re also seeing a spike in rhinovirus/enterovirus infections. These are two types of the many respiratory viral infections that typically rise this time of year with back to school, weather changes and increased pollen counts. It may be that there’s a new strain of rhinovirus or enterovirus that is more virulent than in the past, something that occurs every 6-10 years. We know viral infections can also lead to bacterial pneumonias (typical or atypical).

What care is your team providing for children in the hospital with pneumonia?

These children are provided supportive care in the hospital, which varies depending on their specific symptoms and needs. It may include hydration via IV or by mouth, or oral hydration via nasogastric tube (tube from nose to stomach) for children who can’t take liquids by mouth. Oral is always preferred, especially now with the shortage of IV fluids due to Hurricane Helene storm damage. They may also receive oxygen through a nasal cannula, mask or in very severe cases a ventilator (with a tube from the mouth into the breathing passages).

Antibiotics are an important component of care if a bacterial infection is suspected. We’ll also give steroids and albuterol to patients who experience an asthma attack in addition to their pneumonia.

Do you expect that this will improve or get worse in the coming weeks?

It’s likely to worsen with pollen and mold counts rising, colder weather keeping everyone inside and the holidays bringing people together. Asthma is triggered by infection and cold weather, so we often see patients with asthma needing extra care this time of year as well.

When should families seek medical care for children’s respiratory symptoms?

Not all cases of respiratory illness require care in a medical setting. That said, if you notice any of the following symptoms, we urge you to check with the pediatrician if possible or bring your child to the emergency room:

High fever (higher than 100.4˚F for infants younger than 3 months, or higher than 102.2˚F in children older than 3 months) that lasts more than 2-3 days despite Tylenol and/or Motrin

Inability to drink liquids or vomiting so much that they’re not urinating regularly (fewer than three wet diapers per day in an infant, using the bathroom less than once per day in older children)

Dry lips or mouth

Working hard to breathe/catch their breath (seeing their ribs with each breath, belly breathing more than usual, gasping for air, inability to speak if they’re typically verbal)

If your child has asthma, cough with wheezing, needing more than four breathing treatments per day, and working hard to breathe with no response to breathing treatments would all warrant medical assessment and care.

Should families try any care at home for respiratory symptoms before seeking medical treatment?

For mild symptoms, we encourage lots of liquids and Tylenol or Motrin for pain relief. Honey can help decrease cough but should only be given to children over 1 year of age (there’s a risk of botulism in little ones with immature digestive tracts). Children with asthma should follow their asthma action plan instructions.

If symptoms begin to cause concern, seek medical care right away.

What are the best ways to protect ourselves and our kids from getting sick?

Infection prevention measures are essential, including:

Washing your and your child's hands

Staying home and away from others until symptoms are improving and there is no fever for 24 hours without the assistance of fever-reducing medication

Getting the flu vaccine (now is the time to get the vaccine and start building immunity)

Staying up to date on COVID-19 vaccines

Getting all childhood vaccines on schedule

Wearing a mask if tolerated, especially if you have a weakened immune system or are recovering from illness

A version of this story was originally published by Children’s Hospital of Richmond at VCU

[sparkylurkdragon]

A thought, regarding Cujo: I think Donna's apparent symptoms of rabies at the end were psychosomatic.

Cujo's rapid infection is just barely within the bounds of plausible, but Donna's next-day symptoms and later recovery aren't. She also doesn't actually display normal human symptoms of rabies, in particular biting the paramedic: the urge to bite things doesn't really show up in rabid humans. If rabies causes aggression in humans at all, they display it via the usual human means of expressing aggression, such as using fists or their voice.

She does, however, display stereotypical canine symptoms of rabies. Donna doesn't really know how rabies works, medically, but she has a common knowledge understanding of it combined with the hellish example Cujo set. After the horrific experience she just went through, she loses it from stress and trauma and temporarily embodies what her subconscious thinks is happening. For a little while there, she believed her rage was coming from a rabies infection, and her mind made it real.

The paramedic she bit went through the rabies treatment course because you do not fuck around with rabies and he did get bitten by someone who might have been rabid, but the treatment Donna got was in fact the normal rabies immune globulin and vaccination course, along with treating her wounds.

[heardatmedschool]

“Vancomycin is a bad antibiotic, get over it.”

[flyonthewallmedstudent]

Psittacosis

Let's open with a case report, like we're on an episode of house.

Case Report

35 yo otherwise well, suddenly presents with 2/52 of high fevers and a headache (usually this means > 39)

a/w chills and rigours, responsive to medication/presumably panadol and intermittent (would resolve then come back)

no respiratory symptoms

She had neutrophilia and intrestingly, a CRP of merely 30.

CXR revealed nonspecific consolidation in 2 lobes, they followed this up with a CT revealing pretty impressive ground glass opacities (or GGOs)

She was empirically treated on IV tazocin only (I'm used to atypical coverage empirically started if there's even a whiff of resp, which she may not have had symptoms but her CXR confirms this)

eventually she was on referred to the authors, who felt her CT findings with consistent with psittacosis and treated her with doxycycline which resolved her symptoms in 48 hrs

on further history, it was revealed that she had parrots at home, one had died 2 days preceding her symptoms and she was sleeping next to its body at night (crazy)

What is it:

psittacosis is a zoonoses (transmitted by animals, animals = reservoirs), in this case, transmitted by birds. Orthinoses if birds in general, but psittacosis if referred to macaws, parrots etc. YOu can also catch it from chickens and turkeys.

Some what related is Bird fancier's lungs. Which just sounds fancy.. I'm sure it's just an old term.

Bird fancier's lung refers to a hypersensitivty pneumonitis (ILD) caused by bird exposure. DIfferent disease process, but birds is the come denominator. INhaled bird particles

Psittacosis specifically refers to the infective disease process caused by a bacteria. It was 'identified" or reported in the 1870s, when a cluster of 7 swiss patients developed the same symptoms and found to have possessed tropical birds.

Similarly, in the 1930s there was an outbreak in the US with a mortality of up to 20% (80% in pregnant women), also attributed to parrots from South America.

Eventually, with further scientific development, the causative pathogen was identified as chlamydia psittaci, an atypical intracellular organism.

Psittacosis is a significant differential to consider in community acquired pneumonia as it has a high mortality if left untreated. But it is rare, and causes about 1% of cases in the US. Part of this is due to improved hygiene practices and strict importation guidelines of tropical birds.

It's spread through the inhalation of dust with either dried faeces or respiratory secretions from infected birds.

Clinical features

Variable! but the key thing on history is birds

incubation time can be anywhere from 2 days to 20

Flu-like (fevers/chills/myalgias/arthralgias/malaise/headache)

high fevers is key

respiratory symptoms - does not always present as per the case report, and can be mild on spectrum (dry cough) to more severe

if systemic, can also get photophobia, deafness and epistaxis

Rare (particularly where doxycycline or azith are prescribed at a low threshold): hepatosplenomegaly (look out for LFTs), GI symptoms (remember CAP can present with diarrhoea, nausea/vomiting --> always do a CXR)

even rarer: endocarditis or myocarditis, encephalitis or hepatitis (usually the complications of untreated disease)

Increased risk groups:

pet shop owners

bird owners

farmers

zoo, lab workers where birds are kept, vets, avian quarantine station workers

poultry handlers/workers

So ask if they live or work with birds, or had recent exposure.

INvestigations

serology is gold standard - so looking for antibodies in blood tests

it's intracellular - so hard to culture if even possible on standard blood cultures

elevated ESR/CRP may see LFT derangement and creatinine rise in systemic illness

CXR- usually lower lobe changes, if CT is done, you can get pulmonary infiltrates with GGOs

Treatment:

usual culprits for atypical coverage: azithromycin 3 days or doxycycline 100 mg BD for 14/7

Differentials

always broad if systemic features only (also consider IE and other causes of sepsis)

with resp symptoms - legionella, Q fever, mycoplasma, tularaemia (except for tularaemia, the rest are also covered by doxycycline)

In clinical practice, I'm so used to just having atypicals on board for any cases of atypical pneumonia. I really take it for granted. But will consider this differential more myself in cases of PUO - but I feel like there should be at least CXR findings regardless.

Anyway, prognosis is very good so long as it is treated.

Sources:

CDC guidelines

Case Report: Importance of Clinical history in Psittacosis

StatPearls

Wiki