15 December, 2010

Whooping Cough, Guillain Barre, and Avian Influenza Making Headlines


Spotlight on Whooping Cough

This summer, CDC reported on a dramatic rise in whooping cough cases in California.  As of the most recent MMWR report, California has had 2,625 cases to date, a four-fold increase from last year’s 646 cases.   Although the illness is seldom serious in adults, whooping cough can be deadly in infants.  Communities across the United States have reported outbreaks and infant fatalities since the initial surge in California.  HealthMap has reported alerts in a dozen states in the last month alone.

Lack of vaccination was an obvious suspect.  Immunity to pertussis decreases with age, so adults vaccinated in their childhood may now be susceptible to whooping cough.  These adults could then pass it on to infants and children.  Furthermore, many of the early cases were in San Diego, which has a vocal anti-vaccine community.

While vaccination is clearly an important tool in fighting these outbreaks, two recent news stories highlight other concerns.  Researchers from Baylor College of Medicine recently investigated vaccine storage.  They found “one-quarter of 54 vaccine refrigerators in . . . community health centers had temperatures that dipped into the freezing range, most commonly at night and on weekends.”  When the pertussis vaccine freezes, its efficacy can be severely compromised.

Mutation of the pertussis bacteria could also decrease the effectiveness of the vaccine.  Years ago, Dutch researcher Dr. Frits Mooi raised the possibility of whooping cough adapting to evade the vaccine.  He believes a new type of pertussis is playing a role in the current outbreaks.  KPBS in San Diego has a thorough discussion of this idea along with another prominent researcher’s counter argument that increased awareness and diagnosis of whooping cough is adding to the reported cases.

The current surge in whooping cough cases is likely due to numerous factors.  Regardless of the underlying factors, vaccination remains a critical tool is protecting those most vulnerable to it.  The CDC recommends that all adults get a one-time booster of adolescent/adult tetanus-diphtheria-pertussis vaccine (Tdap).

Guillain Barre Syndrome in Mexico

The General Directorate of Epidemiology of the Federal Government in Mexico has issued an “epidemiological alert for outbreaks of acute flaccid paralysis” in Nayarit and Orizaba (Veracruz). There have been 7 cases in Nayarit and 23 in Orizaba. There have been two deaths registered so far. One of the deceased was diagnosed with Guillain Barre syndrome.
                  
Guillain-Barre syndrome (GBS) is a rare, but sometimes fatal, inflammatory disease that affects the peripheral nervous system and can leave its victims temporarily paralyzed. GBS typically affects people after a minor infection like a respiratory or gastrointestinal one. If GBS affects respiratory muscles, its effects can be fatal because those inflicted will no longer be able to breathe. First symptoms of GBS include tingling or weakness in the legs followed by a spread of the same feelings in the arms and upper body. This ascending spread can take weeks or happen in a matter of days.

Avian Influenza Returns

In recent weeks, avian influenza has returned to news headlines in several countries. On November 19th, a new human case of H5N1 was confirmed in a woman from Hong Kong. This case marks the 21st case of human infection in Hong Kong SAR China to date. After laboratory tests confirmed the patient contracted the virus while visiting mainland China, and no additional cases were found, Hong Kong lowered its bird flu alert level from “serious” to “alert.”

Egypt reported a confirmed case of H5N1 in a female patient from Gharbia Governorate on December 4th. The patient died on December 2nd, becoming the 37th death in Egypt out of the country’s 113 cases to date.

Most recently, on December 9th, a female from Bandung, West Java, Indonesia was confirmed as the latest human case of H5N1. Of the 171 cases of H5N1, avian influenza, in Indonesia to date, 141 have been fatal.

Vietnam and South Korea both have recently reported avian influenza outbreaks in wild birds, however no human cases have been associated with either of these new outbreaks. 

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