Thursday, May 18, 2023

Brazil MOH Statement: Monitoring Potential H5N1 Human Infection

Espírito Santo (ES) - Credit Wikipedia


Two days ago the Brazil Announced their 1st Detection of HPAI H5N1 in Wild Birds in the coastal state of Esprito Santo.  Overnight the Brazilian MOH announced they were investigating the illness of a 61 y.o. Park employee in the same region over suspicions it might be H5N1. 

Samples have been sent to their Central Public Health Laboratory, and will be forwarded to  FIOCRUZ (Fundação Oswaldo Cruz) for futher analysis.  For now this is merely a suspected case. 

My thanks to @Misael on twitter for the head's up and link to the following statement by the Brazilian MOH.  I'll have a bit more after the break. 

About a suspected case of avian influenza in humans in Espírito Santo

 Published on 5/17/2023 7:04 pm Updated on 5/17/2023 7:18 pm

The Ministry of Health has been monitoring and providing the necessary support to the state of Espírito Santo since the notification, this Wednesday (17), of a suspected case of avian influenza in humans in Vitória (ES).

He is a 61-year-old man, an employee of a park where a bird was found that tested positive for the disease. The patient has mild flu-like symptoms and, according to the health surveillance protocol, is in isolation and monitored by municipal health teams.

The sample from the suspected patient and 32 other people who also work in the park are being analyzed by the Central Public Health Laboratory (Lacen) in Espírito Santo. After analysis, the samples will also be sent to Fiocruz, which is the reference laboratory for the state.

It is important to note that no confirmed cases of avian influenza A (H5N1) have been reported in humans in Brazil. The transmission of the disease occurs through contact with sick birds, living or dead. And, according to what has been observed in the world, the virus does not easily infect humans and, when it does, person-to-person transmission is usually not sustained.

The Ministry of Health reinforced, by means of a technical note, the guidelines for surveillance on possible suspected cases of avian influenza in humans after the alert of the Ministry of Agriculture and Livestock (MAPA), on 05/15, of the first cases in birds forests in Espírito Santo .

This may very well turn out to be nothing more than the common cold, but with H5N1 spreading into new territories, the index of suspicion is understandably high. 

As this report comes just 48 hours after the report from the UKHSA: Investigating Two Potential (Asymptomatic) H5N1 Infections In UK Farmers, it is worth putting these reports into context.

While it has been much quieter in recent years, during most of 2000's, and up until mid-2015, reports of human infection with H5Nx from somewhere in the world were practically weekly occurrences (see WHO H5N1 chart below). 

The above chart only shows the laboratory confirmed (and officially reported) cases. During those years we also saw hundreds of `suspected' cases reported by local media, some of whom were buried without ever being tested. 

Many others were deemed false alarms, having tested positive for more mundane respiratory viruses.

Given the limits of surveillance and testing - and the reluctance of some countries to report cases - it is expected that these official numbers only represent a subset of the actual number of cases around the globe. 

While it may be a bit nerve wracking, with heightened surveillance, will will probably hear about a lot of `suspected' cases in the weeks and months ahead.  Many - as we've seen in the past - will probably be false alarms, but a few will be H5 positive. 

Unless and until we see signs of sustained and efficient human-to-human transmission of the H5 virus, the threat to the general public is pretty low. 

But the only way to detect that kind of transmission is to aggressively test all suspected cases.  And the more we test, the more we'll find.  If you followed avian flu closely between 2003 and 2015, you know what to expect.  

If not, my best advice is to fasten your seat belt, because it is likely to be a bumpy ride.