This quote from a Benjamin Franklin letter written 241 years ago still rings true. It's not hard to list bad traits of war, but I find that sometimes we overlook war's contribution to infectious disease outbreaks. Now we're seeing yet another example of this that could expand if not controlled.
Last week revealed a bundle of things to mention, I've tried to trim the list as best I could.
Oropouche HAN
Now the CDC has jumped on the Oropouche virus bandwagon with a new alert via the Health Alert Network. Most useful to front line healthcare providers is an approach for when to consider Oropouche infection more likely:
- Consider Oropouche virus infection in a patient who has been in an area with documented or suspected Oropouche virus circulation within 2 weeks of initial symptom onset (as patients may experience recurrent symptoms), and the following:
- Abrupt onset of reported fever, headache, and one or more of the following: myalgia, arthralgia, photophobia, retroorbital/eye pain, or signs and symptoms of neuroinvasive disease (e.g., stiff neck, altered mental status, seizures, limb weakness, or cerebrospinal fluid pleocytosis); AND
- No respiratory symptoms (e.g., cough, rhinorrhea, shortness of breath); AND
- Tested negative for other possible diseases, in particular dengue. If strong suspicion of Oropouche virus disease exists based on the patient’s clinical features and history of travel to an area with virus circulation, do not wait for negative testing for other infections before contacting your state, tribal, local, or territorial health department.
As I've said previously, it's a clinical syndrome similar to dengue or chikungunya; note the absence of prominent respiratory symptoms. Cuba and Brazil travel has been associated with imported Oropouche in other countries; the disease is also experiencing a rise in Colombia, Peru, and Bolivia.
Mpox
Similarly, we now have mpox reported from Sweden in a traveler returning from an area of Africa where clade I disease has been active. Details are scant, but it was certainly only a matter of time before this happened. Clade I seems to have a higher mortality rate than the more common clade II variant, but it's hard to get precise numbers, much less whether anything is different about the clade Ib variant now being seen. Transmission epidemiology seems to be slightly different than the clade II epidemic of a couple years ago which stemmed primarily from men who have sex with men. In this year's clade I iteration, infections also are being spread by heterosexual encounters, usually via sex workers, and also within households. Young children and pregnant women are at highest risk for complications including fatal outcomes. Like most sexually transmitted infections, public health measures are hindered by infected people not being willing to disclose their sexual contacts. In the Democratic Republic of Congo, the epicenter of the clade I outbreak, homosexuality is not officially illegal but societal norms in the DRC are not favorable to LGBT individuals.
Effective mpox vaccines exist for preventive measures, but a recent press release from the NIH had discouraging news about antiviral therapy. Tecovirimat, aka TPOXX, had been useful in clade II disease. Now, in a placebo-controlled randomized trial of almost 600 mpox-infected subjects in the DRC, tecovirimat outcomes for mortality and for time to improvement were the same as with placebo recipients. I'd like to see the actual study results, but I tend to trust NIH press releases more than most others. CDC has a nice update and map.
Parvovirus B19 Alert
Parvo B19 infection isn't a notifiable disease in the US, so if concern has arisen it usually means something dramatic is going on. This week CDC issued a HAN notice about this infection. The disease is well known to pediatric healthcare providers and to many parents as erythema infectiosum or fifth disease. It's a minor illness unless a pregnant person is infected, with subsequent risk of miscarriage or severe fetal anemia and non-immune hydrops fetalis. Individuals with chronic hemolytic conditions are at risk for aplastic crisis and severe anemia, and immunocompromised people have higher risk of complications. Read more if you need a refresher.
Is It Time for Universal Screening for Congenital CMV?
Last week's MMWR reported on the first 12 months' experience with Minnesota's universal newborn screening program for cCMV; it began in February 2023. 184 of 60,115 (0.31%) newborns screened on a dried blood spot had positive CMV results. Note that screening dried blood spots is less sensitive than other methods; 3 infants with cCMV with negative blood spot results and were picked up by other means. Buried in the report was the interesting finding that of 11 infants with permanent hearing loss, 4 passed their hearing screening test as newborns. Clearly we need more than universal hearing screening to identify at-risk infants. I look forward to further outcome data on Minnesota's program.
Dinner at the Sick Restaurant (apologies to Anne Tyler)
I like to think of myself as an adventuresome diner, but probably I would have drawn the line at these 2 delicacies I found at ProMED, the listserv I've used for decades.
Chicken liver sashimi is a new one on me, but now linked to an outbreak of campylobacteriosis in Japan. (You'll need Google translate for this one.) Perhaps slightly less disgusting is the idea of smoked non-eviscerated fish. Recent testing found a commercial product potentially contaminated with botulinum spores; thankfully no clinical cases have been reported. I've eaten sardines from a can. They also are non-eviscerated, but apparently the fish reported this week were capelin and exceeded the length allowable for packaging non-eviscerated fish. The product was produced and distributed by a company in Florida.
Covid
Meanwhile, let's not forget about our old friend. National wastewater levels are still up.
Levels might be tapering off in some parts of the country.
Meanwhile, clinical indicators suggest we're going to be seeing increasing cases the next few weeks at least. Here's an example with percent test positivity from the same link as above. It's a little higher than it was a year ago, though it's difficult to compare time periods since different factors now drive test-seeking behavior.
Meanwhile, if we can believe news reports (the FDA can't disclose approvals ahead of time), the new KP.2 variant-based mRNA covid vaccines should be available later this week. The Novavax vaccine presumably will be ready a little later. Timing for when to get the new vaccine should be based on individual considerations, including immunocompromised state, travel plans, and other factors. However, trying to predict the amount of covid activity over the coming months is only slightly better informed than a roll of the dice. Here's the current forecast from CDC.
Polio in Gaza
Not that it's unexpected, but a case of polio has been reported in a 10-month-old child in Gaza. This child would have been born just near the start of the new war and presumably was never immunized. Breakdowns in the health system as well as with clean water and sanitation are ideal for a reappearance of polio; it hasn't been seen in Gaza in 25 years. The UN has called for a "polio pause" to allow vaccine distribution. I try to avoid political statements in this blog, and I won't change that now, but I think my old friend Ben Franklin had it right about war.
Batesian Mimicry
To end on a lighter note, when I first saw this term I immediately thought of Norman Bates and "Psycho," perhaps Hitchcock's most famous movie. But no, it's not (spoiler alert) Norman mimicking his mother. This refers to Henry Lewis Bates' 1862 publication on butterflies in the Amazon. For an easier read, try this Wikipedia page. It explains my astonished update in last week's post that the mysterious black butterfly in our garden was in fact a dark variant of the easily recognized tiger swallowtail. Apparently it is an example of Batesian mimicry whereby a vulnerable butterfly species develops the ability to mimic a less desirable (to predators) butterfly. In this case, the tiger swallowtail mimics the unpalatable and toxic pipevine swallowtail. I mentioned last week that I had probably forgotten a lot about what I learned about butterflies in my childhood. I certainly don't remember anything about Batesian mimicry or dark tiger swallowtails. Needless to say, I've been down a rabbit hole all week about this. When I went back to my 3 texts on butterflies, all mentioned the black variant in the tiger swallowtail section but not in the sections on black-colored swallowtails where I was looking. As you can see below taken from "Mimicry and the Swallowtails," they are very different but in fact have subtle similarities that escaped me.
I can think of two reasons for universal CMV screening:
1. To identify infants at risk for later onset hearing loss
2. To treat infected infants
Which of these /both/other - do you feel would justify universal screening ?
Interesting question with no clear answer at the moment. A nice study from a few years ago suggested that universal screening was cost effective. However, it was a modeling study that needs validation in real world settings.
Beyond that, all efficacy of screening programs will depend on the rate of the condition in the general population, the accuracy of the screening test, the ability to apply interventions to improve outcomes, and most importantly the effect size - how much difference the intervention makes in patient outcome. cCMV is very common, with most studies suggesting prevalence of 0.5 - 1% of all live births. However, most of these babies will not have significant clinical sequelae. Screening tests vary - ideally the test would have high sensitivity, we don't want to miss anyone and probably would accept a reasonable number of false positives. Here, using the blood spot card is a good idea since it is already being collected for other reasons, but this method has low sensitivity. Salivary or urine PCR is a better test but significantly more expensive. A very important issue particularly with cCMV is that treatment studies of infants with hearing loss but no other symptoms of cCMV have shown variable results. I discussed 2 studies in my 2/4/24 and 2/11/24 posts; cCMV experts disagree with one another about whether treatment for isolated hearing loss with cCMV is beneficial. Both studies demonstrate how difficult it is to recruit subjects for these studies. Also, remember that treatment of cCMV will suppress CMV viral load, but once therapy is stopped the levels come back up. Antiviral treatment doesn't eradicate CMV from the body; like all herpesviruses (HSV, VZV, EBV for example), it's the gift that keeps on giving.
My practice now is heavily weighted towards telemedicine consultations at regional hospitals in the DC area, with mostly newborn services. Recently I joined a team trying to develop guidelines for targeted cCMV testing; i.e. not universal screening, but using selected clinical and lab criteria to determine whom to test. This goes beyond just testing newborns who fail their newborn hearing screen (Virginia and other states have laws that mandate cCMV testing for these children) and is particularly important for premature infants who may not be able to have hearing screens performed early on due to requiring respiratory support and other conditions. Recently we were able to put together a pathway, but now need to see how it performs. One of the problems is that the intervention is centered on the birth hospital, but often most of the follow up and scheduling of subspecialty visits falls to the primary care provider. Assessing impact of the screening is difficult also.
So, that's a long answer to what is fundamentally a simple question. Universal screening certainly would be easier initially, but assessing impact and costs for such an intervention is much more difficult.
Thanks for your question!