Respiratory Virus Activity in Southern California

Respiratory Viral Activity In Southern California

This blog has been on a month long hiatus due to the normal end of respiratory viral season. However, as you are all aware we are in the midst of an influenza pandemic with a novel virus: H1N1, formerly known as "Swine Flu".

The virus is now at pandemic levels per CDC and WHO criteria and the most up to date information can be accessed at these websites as well as the Los Angeles County website (http://www.lapublichealth.org/acd/Flu_Sea_Surveillance.htm)

The local numbers being reported out of our are not large at the present time, but much higher than what would be expected for this time of the year. As of June 26, 2009, 27,717 confirmed and probable infections with pandemic influenza A (H1N1) virus and 127 deaths (33 deaths in individuals less than 25 years, 89 deaths in adults 25 years of age older, and five deaths with unknown age) have been identified by CDC and state and local public health departments.

Of additional interest is that with the increased testing of febrile respiratory illnesses we are also seeing a jump in other non-influenza viruses such as parainfluenza (type 3) and human metapneumonvirus. All that coughs is not influenza!

Influenza Activity Nationwide

Respiratory Viral Activity In Southern California

Increased testing from all centers

There is very little RSV circulating (1.4% of samples submitted were positive) but we have had a huge uptick in the number of specimens being tested. This is due to the recent H1N1 influenza (formerly Swine Flu) pandemic that started at the end of last month. Due to increases in testing we are seeing quite a bit of parainfluenza and influenza B, more than we would normally know about this time of year.

The best source for up to date information about this new influenza strain can be found on the Los Angeles County's Website (www.ladhs.org) and the CDC's website (www.cdc.gov/H1N1flu).

Respiratory Viral Activity In Southern California

Respiratory Viral Activity In Southern California

As you can see from the graphs we are at the end of SEASONAL influenza and RSV seasons. We had only a few RSV positive samples last week for 1% of tested samples.

We are seeing some Parainfluenza (mostly 2 and 3) and a few human metapneumoviruses as well.

We have had a few influenza B isolated and of course we are all keeping our eyes fixed on the changing situation here and abroad with Swine Flu (H1N1).
The most up to date information can be obtained on the CDC website: CDC.gov/swineflu and I would recommend consulting this for questions concerning possible suspect cases. Currently , individuals in California with a positive exposure history who are symptomatic and test positive for influenza A are having their isolates analyzed by the county health departments for verification of swine flu. Recommendations for isolation, treatment and prophylaxis can be found on this frequently updated website.

RSV Activity

Respiratory Viral Activity

RSV Activity

All Respiratory Viruses (including hMPV)

Respiratory Viral Activity In Southern California

Respiratory Viral Activity In Southern California

We are certainly winding down RSV (and influenza) season in Southern California. We had a late and slow influenza season and are just now seeing the tail end with more B in the community than A (we had twice as many B isolates last week than A, although the numbers are quite small). Interestingly we are also seeing some late season human metapneumovirus. Only two of our sites report detection of this virus, but hopefully next season we will have more sites performing PCR for this agent. Last week we had more hMPV isolates than RSV, influenza, adenovirus and parinfluenza combined!! We have now been <10% for two consecutive weeks, so officially we are OUT of endemic RSV, but stay tuned for detection of late season influenza and hMPV!

RSV Activity