Epidemiologic Investigation of Highly Pathogenic H5N2 Avian Influenza Among Upper Midwest U.S. Turkey Farms, 2015.

In 2015, an outbreak of H5N2 highly pathogenic avian influenza (HPAI) occurred in the United States, severely impacting the turkey industry in the upper midwestern United States. Industry, government, and academic partners worked together to conduct a case-control investigation of the outbreak on turkey farms in the Upper Midwest. Case farms were confirmed to have HPAI-infected flocks, and control farms were farms with noninfected turkey flocks at a similar stage of production. Both case and control farms were affiliated with a large integrated turkey company. A questionnaire administered to farm managers and supervisors assessed farm biosecurity, litter handling, dead bird disposal, farm visitor and worker practices, and presence of wild birds on operations during the 2 wk prior to HPAI confirmation on case premises and the corresponding time frame for control premises. Sixty-three farms, including 37 case farms and 26 control farms were included in the analysis. We identified several factors significantly associated with the odds of H5N2 case farm status and that may have contributed to H5N2 transmission to and from operations. Factors associated with increased risk included close proximity to other turkey operations, soil disruption (e.g., tilling) in a nearby field within 14 days prior to the outbreak, and rendering of dead birds. Observation of wild mammals near turkey barns was associated with reduced risk. When analyses focused on farms identified with H5N2 infection before April 22 (Period 1), associations with H5N2-positive farm status included soil disruption in a nearby field within 14 days prior to the outbreak and a high level of visitor biosecurity. High level of worker biosecurity had a protective effect. During the study period after April 22 (Period 2), factors associated with HPAI-positive farm status included nonasphalt roads leading to the farm and use of a vehicle wash station or spray area. Presence of wild birds near dead bird disposal areas was associated with reduced risk. Study results indicated that the initial introduction and spread of H5N2 virus likely occurred by both environmental and between-farm pathways. Transmission dynamics appeared to change with progression of the outbreak. Despite enhanced biosecurity protocols, H5N2 transmission continued, highlighting the need to review geographic/topologic factors such as farm proximity and potential dust or air transmission associated with soil disruption. It is likely that biosecurity improvements will reduce the extent and speed of spread of future outbreaks, but our results suggest that environmental factors may also play a significant role in farms becoming infected with HPAI.

A case-control study to assess possible triggers and cofactors in chronic fatigue syndrome.

PURPOSE: To assess possible triggers and cofactors for chronic fatigue syndrome (CFS) and to compare levels of selected cytokines between cases and an appropriately matched control group. PATIENTS AND METHODS: We conducted a case-control study of 47 cases of CFS obtained through a regional CFS research program maintained at a tertiary care medical center. One age-, gender-, and neighborhood-matched control was identified for each case through systematic community telephone sampling. Standardized questionnaires were administered to cases and controls. Sera were assayed for transforming growth factor-beta (TGF-beta), interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, and antibody to Borrelia burgdorferi and Babesia microti. RESULTS: Cases were more likely to have exercised regularly before illness onset than controls (67% versus 40%; matched odds ratio (MOR) = 3.4; 95% CI = 1.2 to 11.8; P = 0.02). Female cases were more likely to be nulliparous prior to onset of CFS than controls (51% versus 31%; MOR = 8.0; 95% CI = 1.03 to 170; P = 0.05). History of other major factors, including silicone-gel breast implants (one female case and one female control), pre-morbid history of depression (15% of cases, 11% of controls) and history of allergies (66% of cases, 51% of controls) were similar for cases and controls. However, cases were more likely to have a diagnosis of depression subsequent to their diagnosis of CFS compared to a similar time frame for controls (MOR = undefined; 95% CI lower bound = 2.5; P < 0.001). Positive antibody titers to B burgdorferi (one case and one control) and B microti (zero cases and two controls) were also similar. CONCLUSIONS: Further investigation into the role of prior routine exercise as a cofactor for CFS is warranted. This study supports the concurrence of CFS and depression, although pre-morbid history of depression was similar for both groups.

Infectious diseases and child day care.

The number of day care centers and home care facilities has steadily increased in the United States. Recent interest has focused on the possible relationship between attendance at child day care facilities and the occurrence of certain infectious diseases. A variety of infectious agents have been reported as causes of illness among children and staff in day care programs. In general, however, concurrent risks for these infections among children attending and those not attending day care programs have not been established by prospective studies. A review is made of the pathogens that have been associated with infections in day care settings, patterns of occurrence of infectious diseases in day care facilities, aspects of control and prevention of these diseases, and controversies related to infectious diseases in child day care facilities. Aspects of this problem that warrant further research are outlined.

Prospective surveillance of Haemophilus influenzae type b disease in Dallas County, Texas, and in Minnesota.

Among children less than 12 years of age residing in Dallas County, Texas, and in the state of Minnesota we conducted prospective, active surveillance of invasive Haemophilus influenzae disease. During 18 months, 616 cases were identified, of which 600 were caused by type b organisms. The annual incidence of disease was significantly greater in Dallas than in Minnesota (109 v 68/100,000 children younger than 5 years of age, P less than .001) and was greater in Dallas, even when rates for white children in the two regions were compared (P less than .001). Other regional differences were observed. In Dallas, a larger proportion of cases were in children attending day-care centers (27% compared with 12% in Minnesota, P less than .001) and more patients attended day care for greater than 40 h/wk (56% compared with 30% in Minnesota, P less than .001). Outer membrane protein subtyping of isolates revealed that in Dallas 6U isolates were associated significantly with cases in black children who attended day care. In Minnesota, but not in Dallas, isolates with subtype 1H were associated significantly with cases in children in day care. These data indicate that there are regional differences in the epidemiology of type b Haemophilus disease that may relate to differences in strains, day-care practices, or other unknown cultural or environmental factors. Finally, because only 15% of systemic Haemophilus disease in these regions occurred in children in the age groups recommended for vaccination (24 to 59 months), the new Haemophilus type b polysaccharide vaccine is expected to have a limited impact on the overall incidence of disease.

Hepatitis B infection in Minnesota: a case for universal immunization.

BACKGROUND: In 1993, the Minnesota Department of Health focused on using multiple vaccination strategies to prevent the transmission of hepatitis B virus. METHODS: Strategies aggressively pursued included the universal screening of pregnant women for hepatitis B surface antigen (HBsAg) and the universal vaccination of infants and adolescents. Universal strategies were deemed necessary because previous selective vaccination of high risk groups had failed to significantly reduce hepatitis B transmission. RESULTS: Surveillance data showed that in Minnesota from 1994 to 1996, the universal HBsAg screening of pregnant women identified 761 infants born to HBsAg-positive women. The vast majority of these at risk infants received prophylactic treatment and were vaccinated at birth. Vaccination coverage was 78% (+/-4.2%, 95% confidence interval) for children ages 19 to 35 months who were born between August, 1993, and November, 1995. Most counties in Minnesota rarely report any cases of hepatitis B, and since 1991, less than 100 acute cases per year have been reported for the entire state. CONCLUSIONS: The Minnesota Department of Health has demonstrated that implementation of universal hepatitis B vaccination strategies can be successful among a generally low risk population.

Infectious diseases and child day care.

It is estimated that more than 5.3 million children attend out-of-home child day care in the United States. This includes 2.1 million children who attend approximately 63,000 licensed child day-care centers. An additional 500,000 children receive care in 105,000 regulated day-care homes. Since the total regulated child care slots available in centers and homes are only 2.6 million, some 2.7 million additional children are likely attending unregulated family day-care homes. As a result infants and preschool children are intermingled in child care facilities that often lack adequate toilet and hand-washing facilities and are frequently staffed by individuals with little or no training in the area of infection control. Placing children in out-of-home care should not compromise their health and that of the community. The risk of infection can be lessened by teaching hygiene, supervising unregulated day-care facilities and regular antibiotic use so that bacterial resistance may be prevented.

Evaluation of a sick child day care program: lack of detected increased risk of subsequent infections.

A day care center for the short term care of mildly ill children opened in Minneapolis in October, 1985. We conducted a prospective study to evaluate the risk for study participants of acquiring subsequent infections as a result of possible exposure to other infectious agents while at the center. Between June, 1986, and August, 1987, we determined the rates of subsequent infections for 118 children attending the day care center (center-based children) and compared them with rates of subsequent infections for children participating in a home-based sick child care program (home-based children). Of 105 center-based children potentially exposed to respiratory illness while at the center, 24 (23%) developed subsequent respiratory illness compared with 17 (16%) of the matched home-based children (odds ratio, 1.5; 95% confidence interval, 0.7, 3.1). Of 17 center-based children potentially exposed to gastrointestinal illness, 1 (6%) developed subsequent gastrointestinal illness compared with one (6%) of the matched home-based children (odds ratio, 1.0; 95% confidence interval, 0.06, 16.0). Of 12 pairs of children, where the center-based child was potentially exposed to chickenpox while at the center and both were susceptible to chickenpox, 1 center-based child (8%) developed chickenpox compared with 2 home-based children (17%) (odds ratio, 0.5; 95% confidence interval, 0.04, 5.5). We were not able to demonstrate that children who attended the sick child day care center were at significantly increased risk of developing subsequent infections when compared with a matched group of children who did not attend the center.

Physician attitudes and practices regarding universal infant vaccination against hepatitis B infection in Minnesota: implications for public health policy.

Physician attitudes and practices regarding universal infant vaccination against hepatitis B virus infection in Minnesota were assessed approximately 1 year after publication of the Immunization Practices Advisory Committee recommendations. Four-hundred eighteen Minnesota family physicians and pediatricians were sent self-administered questionnaires, with follow-up by telephone. Among physicians who provide care to infants, 67 (29%) of 234 family physicians and 29 (50%) of 58 pediatricians routinely offered hepatitis B vaccine to all infants (overall 33%) (P = 0.002). The recommendations of the Immunization Practices Advisory Committee, the American Academy of Pediatrics and the American Academy of Family Physicians had the greatest positive influence on physicians' opinions regarding routine hepatitis B vaccination. The factors with the greatest negative influence on their opinions were the low prevalence of hepatitis B virus infection in Minnesota and the addition of three injections to the current childhood immunization schedule. Universal infant hepatitis B vaccination remains controversial among Minnesota family physicians and pediatricians. We believe, given the variability in hepatitis B virus incidence and prevalence in the United States and the relatively low risk of most infants, that a single national policy based solely on universal infant immunization may be difficult to implement.

Outbreak of erythromycin-resistant staphylococcal conjunctivitis in a newborn nursery.

We investigated an outbreak of erythromycin-resistant Staphylococcus aureus conjunctivitis in a hospital newborn nursery that used erythromycin eye ointment to prevent ophthalmia neonatorum. Cases occurred in 2 clusters; 20 (14%) of 146 infants in the nursery developed conjunctivitis from July through October, 1987; and 5 (7%) of 69 infants in the nursery developed conjunctivitis during April and May, 1988. A case-control study of the first cluster demonstrated that culture-confirmed cases were more likely than controls to have received prophylactic erythromycin eye ointment or their initial bath from one nurse (odds ratio, 9.0; P = 0.01) or to have been delivered by one physician (odds ratio, 12.7; P = 0.03). The nurse was the only staff person to have a nasopharyngeal culture which yielded erythromycin-resistant S. aureus. Control measures, instituted in October, 1987, included using silver nitrate drops instead of erythromycin eye ointment for prophylaxis; however, in January, 1988, the hospital resumed use of erythromycin eye ointment. No additional cases were identified until mid-April, 1988, when the second cluster of cases occurred. At that time the hospital reinstituted the use of silver nitrate and no additional cases were identified. This investigation illustrates the potential for conjunctival infection with an antimicrobial-resistant pathogen when antimicrobials are used to prevent ophthalmia neonatorum.

A statewide survey of immunization rates in Minnesota school age children: implications for targeted assessment and prevention strategies.

BACKGROUND: A retrospective statewide immunization survey of the 69115 Minnesota children who entered kindergarten in 1992 was conducted. METHODS: Information was collected from school immunization records on date of birth, dates of vaccination for each dose of vaccine, address of residence and race/ethnicity (when available). Immunization rates were assessed retrospectively for each month of a child's life from 2 to 48 months of age. Age-appropriate immunization was defined as receipt of all scheduled vaccines within 30 days of the recommended age. RESULTS: Immunization levels varied by vaccine, age of the child and race/ethnicity. For example at 19 months of age, 73% of students had received measles, mumps, rubella vaccine; however, only 39% had received their fourth dose of diphtheria, tetanus and pertussis vaccine. White, non-Hispanic students consistently had higher vaccination rates than children of other racial/ ethnic groups. For example 45% of white, non-Hispanic students were age-appropriately vaccinated at 16 months of age compared with 25% of Blacks, 30% of American Indians, 30% of white Hispanics and 28% of Asian-Pacific Islanders (Mantel-Haenzel chi square, P < 0.001 for each comparison). Furthermore coverage rates frequently varied significantly by neighborhood, thereby identifying pockets of underimmunization within communities. CONCLUSION: Our data demonstrate that vaccination rates can vary substantially by age, race/ ethnicity and neighborhood. Detailed immunization assessment is necessary so that effective targeted interventions can be developed.

Estimating immunization coverage from school-based childhood immunization records.

To determine the accuracy of school-based childhood immunization records and to describe the effects of their use on estimates of community-wide immunization coverage, we verified the immunizations to 72 months of age for children born in 1986 to residents in Dallas County, TX, and in Minnesota. Verified immunizations were compared with those documented in the school record. Major transcription errors accounted for fewer than 1% of discrepancies between school and provider records. For 99 subjects with 987 verified immunizations in Minnesota, age-appropriate immunization coverage estimated from the school records was within two percent of actual coverage. For 86 subjects with 981 verified immunizations in Dallas County, age-appropriate immunization coverage from the school records underestimated actual coverage by as much as 21%. The primary factor explaining the underestimate in Dallas was incomplete school immunization records for 33 (38%) subjects and 126 (13%) immunizations. Selective recording of immunizations related to the minimum state requirements in Texas contributed to incomplete school records in Dallas County. Verification of the completeness of records selected to estimate immunization coverage is essential if the estimates are used to monitor trends or to make public policy decisions.

An outbreak of acute hemorrhagic conjunctivitis in central Minnesota.

The only confirmed outbreak of acute hemorrhagic conjunctivitis in the continental United States during 1982 occurred in Brainerd, Minnesota. The disease first appeared in a 27-year-old woman during a trip to Tahiti. The patient's two daughters (8 months old and 3 years old) developed mild conjunctivitis two days later. Although the symptoms of all three had completely resolved before they arrived in Brainerd, illness compatible with acute hemorrhagic conjunctivitis developed in five other individuals who shared a house with them there. Symptoms appeared within two days in four of the five and within three days in the fifth. All five had high neutralizing antibody titers to enterovirus 70 (1:128, 1:32, 1:32, 1:128, and 1:256) and one had high antibody titers to coxsackievirus A24 which may cause similar symptoms (less than 1:4 in all cases). The symptoms resolved without sequelae in all five patients within five days. These cases demonstrated that a person who is no longer symptomatic can still infect others and that an infected person can transmit enterovirus 70 for at least eight days after the onset of symptoms.

Ocular involvement in an outbreak of herpes gladiatorum.

An epidemic of herpes simplex virus type 1 occurred in 60 of 175 wrestlers (34%) attending a four-week intensive training camp. Five of these 60 patients (8%) developed ocular involvement that included follicular conjunctivitis, blepharitis, and phlyctenular disease. Cultures of the conjunctiva and eyelid vesicles were positive for herpes simplex virus type 1 in four of the five patients with ocular disease. The viral isolates were compared by restriction-endonuclease analysis, which disclosed that three of the four isolates were the same strain. None of the patients had corneal involvement and there has been no evidence of viral recurrence to date. Herpes simplex virus type 1 is a health risk for wrestlers, and ocular infections are part of the clinical spectrum. Prompt diagnosis and appropriate management of the outbreak may reduce the severity of the outbreak transmission.

Statewide survey of laboratories performing Mycobacterium tuberculosis testing in Minnesota.

Rapid and accurate laboratory detection and identification of Mycobacterium tuberculosis, particularly multidrug-resistant strains, is critical to both public health control measures and patient management. The authors surveyed microbiology laboratories to evaluate whether their methods met national guidelines. As needed, laboratories received individualized recommendations for improvement. The laboratories were resurveyed a year later to assess changes in methods. Current guidelines recommend fluorochrome acid-fast smears, broth cultures, identification by nucleic acid probe or BACTEC-NAP, and BACTEC primary susceptibility panels, which should include pyrazinamide. Of 27 laboratories performing acid-fast smears, 15 used fluorochrome methods. Six of 16 laboratories performing mycobacterial cultures used broth media. Of six laboratories performing species identification, five used nucleic acid probes or BACTEC-NAP. Of five laboratories evaluating drug sensitivity, two used BACTEC and two included pyrazinamide in their protocols. Overall, 24 (89%) laboratories needed improvements; a year later, 16 (67%) of those had altered their methods or made definite plans to do so. Survey results suggest that health departments can facilitate improvements in laboratory testing for pathogens of public health importance.

The medical impact of a bioterrorist attack. Is it all media hype or clearly a potential nightmare?

Even with the technologic sophistication available in the United States today, effectiveness in dealing with a bioterrorist event is limited. Current surveillance systems may be inadequate to detect attacks. Because the onset of illness after exposure to an agent is delayed, even the time and location of the attack may be vague. In addition, most of the medical community is unfamiliar with many of the high-threat diseases, so identification of the problem may be further delayed. Many of us who are involved in studying the many aspects of bioterrorism believe that it is not a question of if such an event will occur but rather when, as well as which agent will be used and how extensive the damage will be. Given the enormity of what is possible, we must prepare for a potential nightmare.

Food-borne disease in the 21st century. What challenges await us?

As the world shrinks and international commerce expands, food-borne illness is likely to become a major public health focus worldwide. Improved surveillance, community education, thorough understanding of the food production chain, use of HACCP strategies, and ionizing radiation are all important for reducing the risks. Primary care physicians play a crucial role in surveillance and early reporting, as well as in educating the public on the importance of basic food safety.