Minnesota Department of Health (MDH) Bug Bytes
May 14, 2003
Vol. 4: No. 6
Topics in this Issue:
1. Decline in Invasive Pneumococcal Disease: Pediatric Pneumococcal Conjugate Vaccine Success Story
2. SARS Update
3. Influenza A (H7N7) in the Netherlands and Enhanced Influenza Surveillance
1. Decline in Invasive Pneumococcal Disease:
Pediatric Pneumococcal Conjugate Vaccine Success Story
Your (clinicians, microbiologists, and infection control professionals) efforts as our Emerging Infections Program (EIP) partners have paid off once more. Your work with us in pneumococcal surveillance was highlighted in a recent New England Journal of Medicine article (2003; 328:1737-46). Invasive pneumococcal disease incidence declined in 2001 compared with 1998 and 1999 in seven active surveillance areas in the U.S. (population 16 million) as part of the EIP. The Minneapolis-St. Paul metropolitan area is one of the EIP surveillance sites. The seven-valent pneumococcal conjugate vaccine was licensed in early 2000 for use in infants and children < 5 years of age (ACIP recommendations are at: http://www.cdc.gov/nip/publications/ACIP-list.htm). The vaccine targets the majority of antibiotic-resistant strains.
The decline in invasive disease among children < 2 years of age approached 70%. A decline of 32% was observed in adults age 20-39 years and 18% in adults over 65 years. The article stated that the declines seen in adults may be due to decreased frequency of transmission from vaccinated children, as young children are a major reservoir for pneumococcal infection. From 1999-2001, the proportion of isolates non-susceptible to penicillin decreased slightly (26% to 24%).
In the Twin Cities during 2002 the rate of invasive pneumococcal disease in children < 2 years of age was 31/100,000, representing an 85% decline from the average annual rate of 208/100,000 in 1996-1999. Active surveillance for invasive pneumococcal disease was expanded statewide in 2002, and that year the rate among children < 2 from Greater Minnesota (36/100,000) was comparable to the Twin Cities rate. After increases in the proportion of penicillin-nonsusceptible invasive isolates from Twin Cities area residents each year from 1996-2000 (from 14% to 27%), there were decreases in this proportion in 2001 (23%) and in 2002 (19%). From Greater Minnesota residents in 2002, there were also 19% of isolates non-susceptible to penicillin.
We are reaping the benefits of the pediatric pneumococcal conjugate vaccine and thanks to your efforts we have been able to document them. We need to continue surveillance to see if strains not in the vaccine begin to occupy niches held by vaccine strains.
2. SARS Update
We continue to receive many calls regarding SARS and continue to investigate possible cases. To date, in Minnesota, there have been 3 probable SARS cases and 8 suspect SARS cases (see CDC website for case definition and other SARS information at: http://www.cdc.gov/ncidod/sars/). Cases have been from Ramsey (4 cases), Hennepin (2), Dakota, Scott, Olmsted, Rice, and St. Louis Counties. They include 5 adults, 3 children, and 3 infants. There have been no deaths and none are currently hospitalized. All have recovered or are recovering. Laboratory testing, including serology, viral culture, and PCR for the coronavirus suspected to cause SARS is still in process or we are awaiting results from CDC. We expect to receive reagents from CDC soon to conduct serology testing, and ultimately PCR testing, at MDH.
3. Influenza A (H7N7)
in the Netherlands and Enhanced Influenza Surveillance
The Netherlands has been reporting outbreaks of highly pathogenic avian influenza A (H7N7) among poultry on several farms since the end of February 2003. More recently cases of H7N7 infection have been reported among pigs and humans in the Netherlands, and among birds in Belgium. As of April 25, 2003, 83 confirmed cases of human H7N7 influenza virus infection had been reported among poultry workers and their families. Most infected persons had conjunctivitis and some had mild influenza-like illness. One individual, a 57-year-old veterinarian who
had visited an affected farm, died April 17 of complications related to H7N7 infection. There has been evidence of person-to-person transmission of H7N7. Additional information is available on the CDC web site at
This is the second reported occurrence of human infection with avian influenza viruses since early February 2003 when 2 human cases of influenza A (H5N2) were reported in a family from Hong Kong. Neither of these influenza strains has circulated widely in the past. In response to these situations, CDC has recommended enhanced surveillance for influenza. In Minnesota enhanced surveillance includes: subtyping all clinical specimens sent to MDH for influenza A virus testing; ensuring Minnesota has at least one sentinel provider site per 250,000 population; and continuing laboratory and sentinel provider surveillance activities year round.
Because there is overlap between the clinical presentation and travel history of persons who may have SARS and those who should be evaluated for infection with influenza A (H5N1), influenza A should be considered in the differential diagnosis when evaluating a SARS patient. Priority should be given to subtyping influenza A viruses isolated from potential SARS cases. MDH laboratory has H5N1 reagents. If you have questions about influenza surveillance, contact Shelly Feaver at 612-676-4008.
Bug Bytes is a combined effort of the Infectious Disease Epidemiology, Prevention and Control Division and the Public Health Laboratory Division of MDH. We provide Bug Bytes as a way to say THANK YOU to the infection control professionals, laboratorians, local public health professionals, and health care providers who assist us.
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