Written by Samuel Rouleau
Spoon Feed
This case series of 46 people who were exposed to poultry or dairy cows and subsequently infected with H5N1 found conjunctivitis as the most common symptom, with no patients requiring hospitalization.
Don’t you know about the bird? Well, everyone has heard about H5N1!
As of January 23rd, there have been 67 human cases of H5N1, with 1 associated death per the CDC. This case series followed 46 people for 10 days after they were exposed to animals (dairy cows or poultry) with suspected or known H5N1 infection. Cases were confirmed with RT-PCR testing.
Exposure and Symptoms –
- 20 were exposed to poultry during culling, 25 to dairy cows, 1 unknown exposure.
- Median symptom duration was 4 days.
- Conjunctivitis occurred in 42 individuals (93%); 15 patients had isolated conjunctivitis.
- Fever (objective or subjective) was present in 22, though more likely in those with poultry exposure compared to cow exposure (60 v 40%).
- Respiratory symptoms were present in 45% of poultry exposure and 28% of cow exposure.
Testing –
- Conjunctival swabs had the best performance characteristics (positive in 88% exposed to poultry and cows).
- Nasopharyngeal swabs were positive in 58% (poultry) and 21% (cows).
- In those with respiratory symptoms, combined nasal-oropharyngeal swabs were positive in 45% (poultry) and 56% (cows).
Treatment and Isolation –
- 39 patients (87%) were treated with oseltamivir, with a median duration of 5 days
- 34 patients were started on treatment within 2 days from symptoms.
- No close contacts became infected or developed symptoms out of the 97 interviewed. There was no reporting on home isolation/precautions.
How does this change my practice?
- Suspect H5N1 in patients with conjunctivitis or viral symptoms with potential exposure.
- Poultry exposure seems to be more associated with systemic symptoms in this limited cohort.
- Establish testing protocols (combined conjunctival and NP swab) with hospital and local health departments.
- Treat presumptively with oseltamivir.
Source
Highly Pathogenic Avian Influenza A(H5N1) Virus Infections in Humans. N Engl J Med. 2024 Dec 31. doi: 10.1056/NEJMoa2414610. Epub ahead of print. PMID: 39740051
