The one or two regular readers of this blog know that I'm a favorite companion at outdoor summer activities, not because of my scintillating conversational repartee but rather due to my fabulous mosquto/gnat magnet properties. No one near me needs to worry about bug bites; all those bloodsuckers are feasting on me. One morning this week I gathered a couple dozen bites in a very short time and have been scratching ever since. I've been waiting for symptoms of West Nile virus infection, nothing so far. Meanwhile, another vector-borne disease may have worse consequences than previously known.
But first, ...
Covid Summer Surge
In spite of many breathless news reports, this is still nothing to get worked up about, other than for high-risk individuals to consider returning to masking in crowded indoor spaces and employing other mitigation strategies. Some of the lay reports seem to forget that wastewater levels are not the same as actual infections. Wastewater covid detections might be decreasing, especially in the West.
Percentage of emergency department visits due to Covid, one rough measure of clinical illness, is increasing though still at low levels.
Meanwhile, we have a little more clarity on one aspect of long covid. In one study, myalgic encephalitis/chronic fatigue syndrome in adults was no more common following covid than following an acute infection-like illness that was negative for covid. I've long been concerned that case definitions and studies haven't been focused on the heterogeneity of long covid. Fortunately, some studies are geared to looking at the ME/CFS cases separately from post-covid symptoms that might be related to end-organ damage persisting after severe pulmonary or other infection.
Avian Flu
Similarly, the highly pathogenic avian flu A H5N1 continues to crop up in dairy and poultry workers but doesn't seem to represent a broad risk to others, with no known human-to-human transmission. I neglected to mention last week some preliminary results from the seroprevalence study in Michigan dairy workers: none of 35 tested workers had antibody to the virus, suggesting that asymptomatic infections aren't common. However, we need a sample size larger than 35 to get a better handle on this.
Last week's MMWR contained a report supporting the impression that this particular avian flu strain in humans is a very mild disease.
Wash Your Parsley
Did you know that the FDA performs regular microbiologic surveillance sampling of foods? Last week they reported results from sampling of basil, parsley, and cilantro, 3 of my favorite herbs. Below are numbers for the prevalence of various pathogens in different herbs; 95% CI are in parentheses.
| Herb | Cyclospora cayatenensis | Salmonella spp | Escherichia coli |
| Cilantro | 9.2% (4.4-16.5) | 2.8% (1.1-5.7) | 0% (0-1.5) |
| Parsley | 1.3% (0.5-2.6) | 0.9 (0.4-1.8) | 0.1% (0.4-1.8) |
| Basil | 0% (0-2.6) | 0.7 (0.1-2.7) | 0.7% (0-1.4) |
For comparison, grocery store Salmonella spp. contamination rates for chicken vary from about 8 to 24%, depending on the study.
Want Some Listeria With Your Liverwurst?
CDC has been investigating a Listeria outbreak linked to deli counter sliced foods, and now one brand of liverwurst tested positive for Listeria. It's possible that a single product could have contaminated slicing devices, causing Listeria to end up in other deli foods. I hope your favorite deli counter practices good cleansing practices for their slicing machines. If not, you might get a side of Listeria with other deli products too.
Ever Heard of Oropouche?
Probably not, unless you are an infectious disease nerd or familiar with the island of Trinidad or the Amazon basin. Oropouche virus (OROV) is still known by the old practice of using a geographic term to name it Now we have new attention focused on this virus, previously thought to cause a relatively harmless though uncomfortable febrile illness. It was first discovered on Trinidad in 1955, in a forest worker from Vega de Oropouche, Trinidad. OROV is endemic to the Amazon basin, and Brazil is seeing a big upsurge in Oropouche fever this year.
With that have come some troubling new reports. OROV is an arbovirus related to dengue, and it mostly causes an acute febrile illness with sometimes very painful myalgias, similar to dengue, zika, chikungunya, malaria, and similar infections. It is transmitted primarily by Culicoides paraensis, a biting midge, but also can be transmitted by other biting insects including Culex mosquitoes.
Last week the Brazilian health ministry confirmed 2 deaths from Oropouche fever, both in healthy young women. The clinical descriptions resemble dengue hemorrhagic fever. Also, the Pan American Health Organization is investigating possible vertical transmission of the virus from 2 infected mothers. One pregnancy resulted in miscarriage, the other with intrauterine fetal death. PAHO has issued guidelines for evaluating possible vertical transmission of OROV. These studies should help us understand if OROV is similar to Zika virus's ability to cause fetal malformations and other severe outcomes. [Note that you may need to activate Google Translate to read these links.]
Meanwhile, I haven't seen any C. paraensis around my house.even though they do range into the northern US, including Maryland. They are pretty tiny, can be less than a millimeter, so good chance I would miss them. I'm somewhat curious to know if I'm also a midge magnet, but really I'd rather not find out.