Minnesota Department of Health (MDH) Bug Bytes
December 12, 2008
Vol. 9: No.8
Today, we announced the first influenza isolate from Minnesota for the 2008-09 season. The isolate was from a 39 year-old man from Chisago County and the isolate was typed as A (H1). MDH does not have the ability to further characterize the strain, but testing with broad-based antisera indicated it appears to be a good match with the H1N1 strain in this year's vaccine.
The CDC issued a health alert today in the MMWR regarding antiviral resistance. There has been limited influenza activity to date in the United States. Since September, 68 influenza viruses from 15 states have been tested for antiviral resistance. Preliminary data show that 45/46 influenza A (H1N1) viruses tested were resistant to oseltamivir; all H1N1 viruses were sensitive to zanamivir. These H1N1 specimens are from 11 states with 29 from two states. All of the 7 influenza A (H3N2) and the 15 influenza B viruses tested were sensitive to oseltamivir and zanamivir. All influenza A (H1N1) viruses tested were sensitive to adamantanes, and all influenza A (H3N2) viruses tested were resistant to adamantanes. The adamantanes are not effective against influenza B viruses.
Currently, data on antiviral resistance are insufficient to provide a stable indication of the prevalence of antiviral resistance at a national or regional level. However, influenza A (H1N1) viruses that have a genetic mutation conferring oseltamivir resistance appeared and circulated during the 2007-08 influenza season in the Northern and Southern Hemisphere, with some Southern Hemisphere countries reporting that a majority of tested A (H1N1) viruses were resistant to oseltamivir; thus, these early U.S. data indicate that oseltamivir-resistance is likely to be high among H1N1 viruses.
Alternatives for antiviral treatment in the setting of potentially widely circulating oseltamivir-resistant viruses have been suggested. These treatment options, which might include preferential use of zanamivir or therapy with a combination of antivirals for certain patients have been outlined in the ACIP 2008 influenza recommendations (http://www.cdc.gov/flu/professionals/acip/index.htm). Currently, the neuraminidase inhibitors oseltamivir and zanamivir remain the recommended medications for treatment and chemoprophylaxis of influenza.
These events are also a reminder that it's not too late to receive influenza vaccine. Beginning with the 2008-09 influenza season, annual vaccination of all children aged 5-18 years is recommended. Also, we strongly encourage health care providers be vaccinated to protect their vulnerable patients.
Learn more about: Influenza>>
Since the introduction of a conjugate vaccine for Haemophilus influenzae type b (Hib) in 1989, the incidence of Hib disease in infants and young children has decreased by 99% to fewer than 1 case per 100,000 children <5 years of age. In the United States, Hib disease occurs primarily in underimmunized children and among infants too young to have completed the primary immunization series.
Although the numbers are very small and we can't draw any conclusions, we recently have seen an increase in pediatric Hib disease, including cases among unimmunized children. Four cases have been reported in 2008 to date, including a 5 month-old and a 1 year-old, both of whom had received two doses of Hib vaccine. However, two unrelated cases were also reported, in a 7 month-old and a 3 year-old, both of whose parents had refused immunization for their children. The 7 month-old child died.
In 2003, there were 3 adult Hib cases (ages 55, 57, and 64) and 2 pediatric cases, in an unimmunized 9 month-old, and a 10 month-old who had received one vaccine dose at 7 months of age. In 2004, there was 1 case in a 41 year-old, and 1 case in a 5 month-old who had not been immunized. In 2005, a single case in a 33 year-old was reported. In 2006, two adult cases (69 and 87 years-old) were reported as well as a case in an unimmunized 8 month-old, and a case in a 1 year-old who had received just one vaccination at 5 months of age. In 2007, 1 case occurred in a 2 year-old who had received two immunizations 1 year apart from each other.
Other sister U.S. EIP sites have not reported similar findings, but this concern is worth watching.
Learn more about: Haemophilus influenzae type b>>
In the November 28 MMWR (at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5747a3.htm) was a report of a 2007 national outbreak of Salmonella serotype I 4,5,12:i:- infections. It highlights the success that we had in solving this outbreak in 2 days when it had gone unsolved in the prior 4 months before there were any reported cases in Minnesota.
The outbreak began in June 2007, and by October, >200 cases had been reported from multiple states with no vehicle determined. On October 3, a national case-control study was begun. As part of this study, we interviewed 4 recent Minnesota case-patients using our standard foodborne illness report form. One of our epidemiologists, Stephanie Meyer, noted that our case-patients were of the demographic profile likely to consume microwave foods (i.e. 20-29 year-old males, 7-10 year olds) and made sure that they were queried about these types of exposures. By October 4, we reported to CDC that all 4 case-patients had consumed Banquet pot pies during the week before illness onset. After our notification, specific questions regarding pot pie consumption were included in the national case-control study.
In the ensuing U.S. study, case-patients were significantly more likely than controls to have eaten a Banquet pot pie (71% vs. 0%, exact matched odds ratio [mOR] = 23.6, 95% confidence interval [CI] = 3.8-infinity). Banquet turkey pot pies were the only variety of Banquet pot pies associated with illness (29% exposure among case-patients vs. 0% exposure among controls, mOR = 9.2, CI = 1.2-infinity).
From January 1 to December 31, 2007, 401 outbreak cases from 41 states were identified. The median age of patients was 20 years (range: 1 month-97 years); half of the patients were female. Date of illness onset ranged from February 20 to December 11, 2007, with a peak in September. Of patients with available information, 144 (50%) of 289 had bloody diarrhea, and 108 (32%) of 338 were hospitalized.
The Banquet pot pie microwave instructions were confusing because different parts of the package recommended different preparation times. Furthermore, instructions for microwaving time varied by wattage. Of 133 patients interviewed, 102 (77%) cooked pot pies in a microwave. Of 78 patients who used a home microwave, only 23 (29%) reported knowing the wattage. Of 8 patients who used a microwave outside the home, 1 (13%) knew the wattage. Forty-eight (68%) of 71 who responded did not let pies stand the full recommended time after microwaving, and 16 (19%) of 84 cooked more than one pie simultaneously, indicating that many patients did not follow microwaving instructions.
The outbreak strain was isolated from 13 unopened Banquet pot pies. All pies that tested positive contained turkey, and all had production dates of July 13 or 31, 2007. Two of these pies underwent separate testing of the crust and filling. The filling tested positive and the crust tested negative for both pies.
Two articles from the EIP FoodNet Program, of which we are a participant, were published in 2006 (Pediatric Infectious Diseases Journal) and 2007 (Pediatrics) examining risk factors in infants for sporadic infections with Campylobacter or Salmonella. Infants have a different diet and are exposed differently to the environment than adolescents and adults, and they also experience high rates of both infections.
For Campylobacter, a case-control study of 123 cases and 928 controls found infections in those aged 0-6 months to be associated with drinking well water, and riding in a shopping cart next to meat or poultry. Breastfeeding was protective. Risk factors for those aged 7-12 months included visiting or living on a farm, having a pet with diarrhea in the home, and eating fruits or vegetables prepared in the home. Infection was associated with travel outside the United States at all ages.
For Salmonella, a case-control study of 442 cases and 928 controls revealed that infection was associated with travel outside the United States, to have attended day care with a child with diarrhea, to have ridden in a shopping cart next to meat or poultry, exposure to reptiles (iguanas, lizards, snakes, turtles), or consumption of meat and concentrated liquid formula in the 5-day period before illness. Breastfeeding was protective. Infant mobility (crawling, walking) and preparation of meat in the home in the previous 5 days was also associated with a lower risk of illness.
Both of these studies suggest there may be modifiable risk factors and corrective actions parents can take to prevent infections in their infants.
Not included in these studies, but somewhat related, and certainly very amusing, was an interview we had last week with the parent of a 3 year-old girl with Campylobacter infection. When asked about exposures prior to illness onset, the parent stated that the child had eaten frost from the inside of the freezer at a grocery store where the boneless chicken breasts were displayed.
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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