October 2006 Maine Epi-Gram

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easy-to-read hardcopy Epi-Gram

Introduction

The Maine Center for Disease Control and Prevention (Maine CDC) routinely conducts surveillance for influenza. Surveillance efforts are enhanced during the winter months, when an increase in influenza activity is typically observed nationwide. This article presents a brief overview of influenza surveillance activities for the 2006-07 season and reviews the national priority groups for the 2006-07 influenza vaccine. Influenza surveillance information is updated weekly and is available at the Maine CDC website www.mainepublichealth.gov.

2006-07 Influenza surveillance activities

Outpatient Influenza-like Illness ( ILI)

Outpatient ILI data are collected through the U.S. Influenza Sentinel Provider Surveillance Network, a collaborative effort between the federal Centers for Disease Control and Prevention (CDC), Maine CDC, and local health care providers. During the 2006-07 season, Maine is recruiting providers (see Text Box) to participate in the U.S. Influenza Sentinel Provider Surveillance Network and meet Maine’s goal of 20 sentinel providers representing the sixteen counties and four largest cities. Sentinel providers report the total number of patients seen in their practices and the number of those patients seen for ILI by four different age groups (0-4 yrs., 5-24 yrs., 25-64 yrs., >64 yrs.) on a weekly basis.

Hospital Inpatients

Inpatient surveillance for respiratory illness admissions is conducted in collaboration with three regional hospitals: Maine Medical Center, Central Maine Medical Center, and Eastern Maine Medical Center. On a weekly basis, these hospitals report the total number of patients admitted from the emergency department and the total number of those patients admitted for respiratory illness. Hospitals utilize patient admission codes, chief complaint data, and/or patient discharge ICD-9 codes 480-487 to identify respiratory illness admissions. During the 2006-07 season, Maine CDC will work collaboratively with three hospitals, representing the southern, central, and northeastern regions of the state.

Laboratory Reporting

The Maine Health and Environmental Testing Laboratory (HETL) works collaboratively with hospitals and private laboratories to collect specimens for respiratory virus isolation and subtyping. Each week HETL reports the total number of specimens received and the number of culture-positive isolates for influenza A (H1), A (H3), A (Undetermined), and influenza B by specimen collection date. HETL also performs Polymerase Chain Reaction (PCR) testing for influenza viruses in parallel with conventional culture. PCR tests are used to detect influenza A and B viruses; influenza A-positive specimens are subsequently tested for H1 and H3. NorDx and Affiliated Laboratory Incorporated also participate in surveillance activities by reporting the total number of respiratory specimens tested for influenza and those that are positive by testing method (e.g., EIA, culture, and PCR).

Outbreaks of influenza or influenza-like illness are notifiable conditions in Maine. The definition used to recognize outbreaks of influenza-like illness varies by setting. Outbreaks of ILI in long-term care facilities (e.g. nursing homes, assisted living facilities, and skilled nursing facilities) are defined as >1 patient with laboratory-confirmed influenza or >3 patients with ILI on the same floor or ward during a short period (e.g., 48-72 hours) in any facility statewide. Outbreaks of ILI in an acute care facility are defined as >1 patient with laboratory-confirmed influenza >48 hours after facility admission. An outbreak of ILI in schools, including elementary, middle and high schools, is defined as daily student absenteeism >15% that is attributable to ILI.

Novel Virus

Enhanced surveillance guidelines for detecting suspected cases of a novel influenza virus, including influenza A (H5N1) have been issued by federal partners. Maine CDC publishes these guidelines on the Maine influenza web site
(www.maine.gov/dhhs/boh/influenza_surveillance_avian-info.htm).
Patients meeting clinical and epidemiologic criteria suggestive for possible novel influenza virus infection will be tested through PCR at HETL.

Death Certificates

The vital statistics offices of three Maine cities, Portland, Lewiston and Bangor, report the number of death certificates on a weekly basis in which pneumonia and influenza are mentioned as the primary or secondary cause of death by town of occurrence. These data were used to calculate the percentage of deaths attributable to influenza and pneumonia.

Pediatric Fatalities

Health care providers and the State Medical Examiner report deaths in persons aged 18 years or younger associated with laboratory-confirmed influenza to Maine CDC. Each report is investigated to obtain additional demographic and illness-related information. Maine reports influenza-associated pediatric fatalities to the federal Centers for Disease Control and Prevention as part of national surveillance efforts.

2006-07 Influenza Vaccine

In the United States, annual influenza vaccine is the primary option for reducing the effect of influenza. The Advisory Committee on Immunization Practices (ACIP) publishes guidance on preventing and controlling influenza annually. Populations are identified as target groups for vaccination according to their risk of morbidity and mortality associated with influenza. Both inactivated influenza and live, attenuated influenza (LAIV) vaccines can be used to reduce the risk of influenza. LAIV is approved for use among healthy individuals aged 5-49 years. Inactivated influenza vaccine is approved for persons aged >6 months, including those with high-risk conditions (See ACIP guidelines for more information:
http://www.cdc.gov/mmwr/PDF/rr/rr5510.pdf).

Maine CDC has prioritized the distribution of state-purchased influenza vaccine in 2006-07 to public health and high-risk settings for vaccination of persons recommended to receive influenza vaccination. Public health and high-risk settings include Federally Qualified Health Centers, Rural Health Centers, nursing homes, long-term care facilities, home care facilities, Indian Health Services, hospitals, and local public health agencies. The Maine Immunization Program will send over 150,000 doses of influenza vaccine to these partners over the next several months.

Public health partners are encouraged to routinely offer influenza vaccine to persons during hospitalization or during regularly scheduled health-care visits, as well as at pharmacies, grocery stores, workplaces, or other locations in the community before the influenza season, so that special visits to physicians’ offices or clinics would be unnecessary. Persons for whom vaccine is recommended, or anyone interested in receiving influenza vaccine, should speak with their health care provider to learn about where in their community influenza vaccine may be available.

When looking over numbers, I am always struck by patterns. Long series of numbers, by the very nature of probability, have seemingly intricate connections. Sometimes these are random links, but sometimes they are the results of nature. The more distinct the picture, the more likely that there is a non-random explanation for the connection. Noticing patterns seems to be characteristic of the human mind, and it’s the easiest step when critically examining a complicated system. The second and more difficult task is to find the cause. Once found, however, we can use this source to our advantage and redirect the flow to create a new pattern.

The first recorded outbreak of West Nile Virus (WNV) in the United States occurred in the month of August, which is long after the first mosquitoes of the year begin to bite. The Centers for Disease Control and Prevention (CDC) reported that for 2001-2002 in the northeast, transmission of WNV to humans occurred between July and November despite the fact that WNV was detected in birds as early as April. In 2005, Massachusetts and New Hampshire found Eastern Equine Encephalitis (EEE) in humans from August into September, and two horses in Maine died from EEE in late September. These results are just examples of a vast amount of evidence that the risk of transmission of these mosquito borne diseases to mammals increases as the mosquito season progresses. This pattern is well documented, but its causes are less evident.

There are several theories that have been posed for the late occurrence in transmission of WNV or EEE to humans, of which two have accumulated substantial evidence. The first is simple: seasons affect the virus cycle. The second deals with the behavior of the mosquitoes as vectors. These two theories are not mutually exclusive.

Mosquito borne viruses appear as a cycle in the United States. Winter is the part of the cycle when the virus is found at low levels in nature. One reason is that mosquitoes don’t like the cold. Some species huddle up as adults in tight tree holes, others pass the winter as larvae in the mud of frozen marshes, and still others sit by as eggs waiting for the spring sun to melt the snow. Only the adults can harbor the disease through the winter, but even they are not actively biting.

The second reason is for the birds. Birds, the principle vertebrate reservoirs of WNV and EEEv, are also seasonal. Some birds fly south, taking the viruses with them. They also have the opportunity to become infected from the bites of southern mosquitoes. Over-wintering birds that are sick either die or recover. The result is that with the mosquitoes inactive and the birds recovered, the virus is almost absent from the north. Some people in the past have suggested that the winter would be the perfect time to get rid of the virus for good, but during the winter the disease reservoirs are unavailable for control.

The next part of the cycle begins when the north tilts back to the sun and the snow begins to melt. It is unclear how many infected mosquitoes survive a normal winter. Some mosquitoes die after being infected, but others probably survive. Even if all the mosquitoes who are infected happen to die, some birds bring the virus back as they return to herald the spring.

The buildup of disease in the spring and early summer is slow because the reservoir of infected insects and birds is low. Moreover, the diseases require time to incubate in both the birds and the mosquitoes. This causes a delay in transmission, so that the diseases spread slowly even under the most favorable conditions for mosquitoes. The relatively small numbers of infected birds and mosquitoes in spring and early summer has been frequently documented by sample tests for the diseases in the blood of birds and in ground-up batches of mosquitoes (Figure 1). It appears that transmission to humans or other mammals is a very rare occurrence, even when disease levels are high in the reservoir species. A few cases in the human population of an entire state with millions of people is likely to be called an “outbreak,” but it is still an extremely rare event. This suggests that when disease levels are low, transmission is improbable.

Figure 1: The percent of bird and mosquitoes tested for WNV and EEEv that were positive arranged by month. This is likely to mirror the level of virus in nature. However, sampling was not designed to facilitate analysis. Testing was started in July and suspended in Early November. Total positive tests = 33 out of 271 tested.

Mosquito Behavior

The seasonality model does not seem to be a completely adequate explanation. For one thing, high infection rates in mosquitoes and birds are not always accompanied by any cases in humans or horses. It also appears that WNV in the U.S. has a somewhat different pattern than in Europe. What factors differ between Europe and the United States? For one thing, the two regions do not share all the same species of mosquitoes.

A new pattern of behavior was discovered when a group of researchers started looking at the behavior of a bird mosquito (Culex pipiens). This is the mosquito that many suspected to be the main mosquito responsible for the first U.S. WNV outbreak. They not only tested these mosquitoes for the virus, but they also tested the type of blood that they were holding in their engorged stomachs. They found that this “bird mosquito” started to bite mammals late in the season. Another mosquito, blamed for EEEv transmission, is starting to be tested as well.

Seasonality and mosquito behavior may explain the pattern we see in late summer and fall human infection, both factors perhaps working in unison. There is still a great deal more to discover, but there is no reason why we can’t start using the information that we have found. Seasonality is an important aspect to have in mind when looking at infection rates. The earlier that we start to see infection, the higher the risk of that virus having a high human infection rate by the end of the season. It is something to consider when trying to control mosquito populations. We can also use the information on mosquito behavior to choose which mosquitoes to worry about, which allows us to focus our control efforts in the appropriate habitats. These factors go into making a risk assessment about a mosquito borne virus. There is undoubtedly more to learn, but with the information already available to us, we can begin to change the pattern. For more information on WNV or EEEv visit the Maine CDC Arbovirus Homepage at
http://www.maine.gov/dhhs/boh/ddc/arbovirus/index.htm
or WNV http://www.cdc.gov/ncidod/dvbid/westnile/
and EEE http://www.cdc.gov/ncidod/dvbid/arbor/eeefact.htm web pages at the Federal CDC website. In addition, please feel free to ask Dr. Deyrup any questions you might have on mosquito borne disease.

This past August, the federal Centers for Disease Control & Prevention (CDC) published the Sexually Transmitted Diseases Treatment Guidelines, 2006,” in CDC’s Morbidity and Mortality Weekly Report (MMWR) Recommendations and Reports. These guidelines for the treatment of patients who have sexually transmitted diseases (STDs) were developed by CDC after consultation with a group of professionals knowledgeable in the field of STDs who met in Atlanta on April 19–21, 2005.

Over 18 million cases of STDs occur in the U.S. each year, with a disproportionate share among young people and racial and ethnic minority populations. The estimated annual direct medical costs of treating STDs and their sequelae are $13 billion. In Maine, chlamydia remains the most commonly reported notifiable disease. Data from 2005 reflects a 6% increase in chlamydia cases (2,253) from 2004 while gonorrhea cases in 2005 decreased 33% (142) since 2004. Even with the decrease in total cases, gonorrhea continues to have a significant impact among men who have sex with men (MSM). MSM accounted for 27% of all gonorrhea cases in 2005. Additionally, in recent years, co-infection with gonorrhea and HIV has proven to be substantial in the Maine MSM community. From 2003- 2005, syphilis cases fluctuated from 2 to 15 cases; there have been 13 cases thus far in 2006. With disease numbers increasing, assuring proper treatment is essential as a critical component of the public health response.

These 2006 Guidelines, which update the 2002 Guidelines, are an important tool to address this major public health challenge. CDC revises the Guidelines periodically, approximately every three to four years, using a scientific, evidence-based process that includes CDC and external expert review of current scientific literature.

To obtain a copy of the guidelines, please go to the federal CDC web site at http://www.cdc.gov/std/treatment/ or call CDC NPIN (National Prevention Information Network) at 800-458-5231 (M-F 9am-8pm ET). A simple one-page reference guide for the 2006 guidelines is currently being printed and will be distributed by the Maine STD Program when it becomes available. For specific questions regarding treatment of disease please contact the STD Program at 287-2046.

Chickenpox is a highly contagious disease, transmitted by the direct contact, respiratory and droplet spread of the organism. It is characterized by sudden onset of low-grade fever, malaise and a skin eruption that leaves a granular scab. The incubation period is 14-16 days with a range from 10 to 21 days. Chickenpox is infectious 1-2 days before to 4-5 days after the onset of the rash. In Maine, mandatory vaccination for varicella was phased in as of 2003 and will be completed by school year 2007. Studies place the effectiveness of one dose of the varicella vaccine above 70%. Breakthrough infection has been reported in vaccinated individuals and one such investigation was conducted in a Maine elementary school earlier this year.

The latest ACIP provisional recommendations call for vaccinating all children younger than 13 years of age with two doses of varicella-containing vaccine. The administration of the first dose is recommended to be at 12-15 months of age and the second dose at 4-6 years of age (i.e., before a child enters kindergarten or first grade). The second dose can be administered at an earlier age provided the interval between the first and second dose is more than 3 months. If, however, the second dose is administered at least 28 days following the first dose, there is no need to repeat the second dose.

The ACIP also provisionally recommends that a second “catch-up” dose be administered for children, adolescents, and adults who previously had received only one dose to improve individual protection against varicella and for more rapid impact on school outbreaks. This second dose can be administered at any interval longer than 3 months after the first dose. The ACIP recommendations place a special emphasis on administering a second dose of varicella vaccine as an outbreak disease control measure to persons who have received only one dose of varicella vaccine, provided that the appropriate vaccination interval has elapsed since the first dose (3 months for people 12 months to 12 years of age and at least 4 weeks for people ≥13 years of age).

Funding limitations prevent the Maine Immunization Program from implementing this two-dose schedule at this time. MIP will continue funding a one-dose schedule.

Since the introduction of mandatory vaccination in 2003, the Maine Immunization Program had moved from aggregate reporting to case-based reporting by school nurses. In 2005-2006 MIP had to suspend this surveillance activity due to FERPA concerns. MIP has now reverted back to aggregate reporting. School nurses are requested to continue reporting the aggregate number of chickenpox cases each week. In the 2004=05 school year, 318 cases of chickenpox were reported. Medical providers are still required to report individual cases within 72 hours of the patient presenting with symptoms.

MRSA Among Students - Maine, 2006

The Maine Center for Disease Control and Prevention, Division of Infectious Disease has recently received an increasing number of reports of skin and soft tissue infections among students attending college, high school, elementary and pre-schools. Some reports include students who participate on athletic teams. School nurses, college health care providers, athletic directors and coaches are encouraged to monitor students for skin and soft tissue infections and promote personal hygiene and environmental cleaning to prevent further spread.

Skin and soft tissue infections are often caused by methicillin-resistant staphylococcal aureus (MRSA) , infections that are highly contagious, particularly when there is oozing of wounds. Transmission of MRSA usual occurs through close contact with a person who has a draining lesion. Competitive sports participants might develop scrapes or cuts of the skin, which could facilitate entry of the bacteria. The use of shared equipment or other personal items that are not cleaned or laundered between users could be a vehicle for MRSA transmission. A health care provider should examine individuals with skin or soft tissue infections that do not resolve quickly.

Maintaining good hygiene and avoiding contact with drainage from skin lesions are the best methods for preventing spread of MRSA infections. Athletic directors, coaches, and dormitory administrators are encouraged to keep facilities and equipment clean and provide adequate supplies of soap and towels. Sports participants with open skin or soft tissue infections should not participate in athletic activities until their wounds are healed. Students should be encouraged to practice good hygiene, avoid sharing towels or other personal items, and inform health care providers and coaches about active skin infections.

Additional information on MRSA, including materials that may be useful for students or families experiencing a MRSA infection, can be found at the Maine CDC website on MRSA:
http://www.maine.gov/dhhs/boh/disease_methicillin-resistant.htm.

If you have any questions or concerns, or if you identify cases of skin and soft tissue infections among your students, please contact the Maine CDC Division of Infectious Disease at 1-800-821-5821.

Contributed by Anne R. Sites

November 14, 2006
Augusta Civic Center

Since 1983, the Maine Center for Disease Control and Prevention (formerly the Bureau of Health), Division of Infectious Disease, Maine Department of Health and Human Services, has organized an annual infectious disease conference targeting public health issues of emerging concern to medical practitioners throughout the State.

This year’s meeting will continue this tradition, and is dedicated to a review of emerging issues in the field of infectious diseases, particularly as they impact the Maine medical community. Issues presented will include challenges in controlling infectious diseases, information on responding to new disease threats, and clinical updates and approaches.

Target Audience - Physicians and allied health care professionals interested in emerging infectious diseases of public health significance.

Continuing Medical Education – Applications will be made to obtain continuing medical education (CME), nursing and pharmacy continuing education credit.

Registration information is available by contacting AdCare Educational Institute of Maine at 626-3615 or visiting
www.neias.orgl A registration fee of $50 will cover conference materials, breakfast, lunch, breaks and continuing education credit.

Department of Health and Human Services
Maine Center for Disease Control and Prevention
286 Water Street
11 State House Station
Augusta, ME 04333-0011