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The direct and interactive effects of climate change on host species and infectious disease dynamics are likely to initially manifest\ at latitudinal extremes. As such, Alaska represents a region in the United States for introspection on climate change and disease. Rabies is enzootic among arctic foxes ( Vulpes lagopus) throughout the northern polar region. In Alaska, arctic and red foxes (Vulpes vulpes) are reservoirs for rabies, with most domestic animal and wildlife cases reported from northern and western coastal Alaska. Based on passive surveillance, a pronounced seasonal trend in rabid foxes occurs in Alaska, with a peak in winter and spring. This study describes climatic factors that may be associated with reported cyclic rabies occurrence. Based upon probabilistic modelling, a stronger seasonal effect in reported fox rabies cases appears at higher latitudes in Alaska, and rabies in arctic foxes appear disproportionately affected by climatic factors in comparison with red foxes. As temperatures continue a warming trend, a decrease in reported rabid arctic foxes may be expected. The overall epidemiology of rabies in Alaska is likely to shift to increased viral transmission among red foxes as the primary reservoir in the region. Information on fox and lemming demographics, in addition to enhanced rabies surveillance among foxes at finer geographic scales, will be critical to develop more comprehensive models for rabies virus transmission in the region. [ABSTRACT FROM AUTHOR]

Alaska public and environmental health authorities investigated a cluster of campylobacteriosis cases among people who had consumed raw, unpasteurized milk obtained from a cow-share program in Alaska. Although raw milk is not permitted by law to be offered commercially, consumers can enter into cow-share agreements whereby they contribute funds for the upkeep of cows and in turn receive a share of the milk for their personal use. Laboratory testing of stool specimens collected from ill persons and from cows on the farm revealed an indistinguishable strain of Campylobacter. In this outbreak, numerous confirmed and suspected cases were not among cow shareholders; therefore, these individuals had not been advised of the potential health hazards associated with consumption of raw milk nor were they informed of the outbreak developments. [ABSTRACT FROM AUTHOR]

Animal hoarding is an under-recognized problem that exists in most communities and adversely impacts the health, welfare, and safety of humans, animals, and the environment. These guidelines address public health and worker safety concerns in handling situations where animal hoarding or other dense concentrations of animals have caused unhealthy and unsafe conditions. Because animal hoarding situations are often complex, a full response is likely to be prolonged and require a cross-jurisdictional multiagency effort. Each animal hoarding case has unique circumstances related to the types and numbers of animals involved, the physical structure(s) where they are being kept, and the health status of the animals, among other factors that must be taken into account in planning a response. Some general public health considerations and associated recommendations for personal protective equipment use are presented that apply to all cases, however. [ABSTRACT FROM AUTHOR]

The article reports on the rate of deaths associated with the pandemic influenza A H1N1 among American Indian/Alaska Natives (AI/AN) across the U.S. from April 15 to November 13, 2009. A study on the burden of H1N1 influenza deaths in AI/AN population found that H1N1 mortality rate among AI/AN is four times higher compared to other racial/ethnic populations. It discovered 426 H1N1 deaths in 12 states during the period, 9.9 percent of which include AI/AN.

Objective: We conducted a review of invasive early-onset neonatal group B Streptococcus (GBS) infections that occurred during 2000-2004 in Alaska to determine the proportion of cases that might have been prevented by complete implementation of the 2002 Centers for Disease Control and Prevention (CDC) guidelines. Methods: Cases were identified from statewide laboratory-based surveillance conducted by the CDC Arctic Investigations Program, and from the Alaska Medicaid database using International Classification of Diseases 9 codes 038.0, 041.02, 320.2, and 482.3. Neonates were considered to have early-onset disease if clinical illness within 6 days after birth was accompanied by GBS isolation from a normally sterile site. Maternal and neonatal medical records were reviewed. Potentially preventable cases were those for whom the 2002 CDC GBS maternal screening and intrapartum antimicrobial prophylaxis (IAP) guidelines were not completely implemented. Preventability of events not related to clinician implementation of the guidelines were not considered. Results: Twenty-one neonates with invasive early-onset GBS disease were identified (0.42/1,000 live births). Three of the eight mothers for whom IAP was indicated, did not receive adequate IAP. Nine of the 13 mothers for whom there was no indication for IAP, had not been screened appropriately. Therefore, a total of 12 neonates were determined to have had potentially preventable GBS disease. Conclusions: Over 50% of the invasive early-onset neonatal GBS cases in Alaska were potentially preventable. The majority of these cases may have been prevented by closer adherence to either specific IAP administration guidelines or to maternal screening guidelines. [ABSTRACT FROM AUTHOR]

The article reports on mortality among American Indian/Alaska Natives (AI/ANs) in 12 U.S. states related to the 2009 influenza A(H1N1) pandemic. According to the findings of a multidisciplinary workgroup created for the pandemic, the mortality rate in the 12 states was four times higher than persons in all other racial/ethnic populations combined during the April 15 to November 13, 2009 period. A total of 426 H1N1-related deaths was reported in the 12 states. The possible reasons behind the vulnerability of the states to H1N1 are noted. INSET: What is already known on this topic?.

Objective: Clostridium perfringens and Bacillus cereus are common causes of reported foodborne illness. On August 6, 2021, the Alaska Division of Public Health identified a multipathogen gastrointestinal outbreak among hospital staff in Homer, Alaska. The objectives of this study were to identify the outbreak source and prevent future illness., Methods: We conducted a retrospective cohort study of hospital staff who participated in luncheon events during August 5-7, 2021, and used an online survey to identify hospital staff with gastrointestinal illness. We defined case patients as people who reported new-onset gastrointestinal illness (diarrhea or abdominal cramping) after food consumption during the luncheon events. We calculated adjusted odds ratios of gastrointestinal illness associated with reported food exposures. We tested available food samples for C perfringens and B cereus and tested case patient stool specimens for C perfringens. We conducted an environmental investigation at the implicated vendor site., Results: Of 202 survey responses, 66 (32.7%) people reported acute gastrointestinal illness: 64 (97.0%) reported diarrhea, 62 (94.9%) reported abdominal cramps, and none were hospitalized. Of 79 people who consumed ham and pulled pork sandwiches, 64 (81.0%) met the case definition; this food item was significantly associated with increased odds of gastrointestinal illness (adjusted odds ratio = 296.4; 95% CI, 76.7-2019.1). C perfringens and B cereus were isolated at confirmatory levels from sandwich samples. C perfringens enterotoxin was detected in all 5 stool specimens tested. Environmental investigators observed other food items at the sandwich vendor that were refrigerated outside the required temperature range (>41 °F); no clear handling deficiencies for the implicated food were identified., Conclusion: Quick notification and effective collaboration can help detect an outbreak, identify the responsible food vehicle, and mitigate further risk., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Streptococcus pneumoniae can co-infect persons who have viral respiratory tract infections. However, research on S. pneumoniae infections that are temporally associated with SARS-CoV-2 infections is limited. We described the epidemiology and clinical course of patients who had invasive pneumococcal disease (IPD) and temporally associated SARS-CoV-2 infections in Alaska, USA, during January 1, 2020-December 23, 2021. Of 271 patients who had laboratory-confirmed IPD, 55 (20%) had a positive SARS-CoV-2 test result. We observed no major differences in age, race, sex, or underlying medical conditions among IPD patients with and without SARS-CoV-2. However, a larger proportion of IPD patients with SARS-CoV-2 died (16%, n = 9) than for those with IPD alone (4%, n = 9) (p<0.01). IPD patients with SARS-CoV-2 were also more likely to be experiencing homelessness (adjusted OR 3.5; 95% CI 1.7-7.5). Our study highlights the risk for dual infection and ongoing benefits of pneumococcal and COVID-19 vaccination, especially among vulnerable populations.

We compared the mortality risk in Alaska among persons with symptomatic coronavirus disease 2019 (COVID-19) during the period the Delta variant was predominant to the risk among those with symptomatic COVID-19 before Delta predominance. The Delta period was associated with 2.43-fold higher odds of death. Unvaccinated persons were 4.49 times more likely to die than fully vaccinated persons., Competing Interests: Potential conflicts of interest. E. Q. M. and K. N. are employees of the US Centers for Disease Control and Prevention (CDC). L. C., M. F., M. T., and J. M. are employees of the State of Alaska Division of Public Health. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2022.)

Background: Haemophilus influenzae serotype a (Hia) can cause severe invasive disease, especially in young children. In 2018, 4 invasive Hia cases occurred in an Alaska community. We used whole-genome sequencing (WGS) to evaluate the relationship of the bacteria from this community and other Alaska patients with invasive Hia., Methods: All carriage (n = 15) and invasive (n = 4) Hia isolates from the outbreak community, together with 15 nonoutbreak Alaska invasive Hia surveillance isolates from 2018, were tested for antimicrobial susceptibility and characterized using WGS., Results: Phylogenetic analysis of both invasive and carriage Hia isolates revealed 2 major clades that differed by an average of 300 core single-nucleotide polymorphisms (SNPs). All isolates from the outbreak community were clustered in 1 subclade, within a larger clade containing 3 nonoutbreak invasive Hia isolates. Comparative genomics did not reveal any genetic mutations that distinguished carriage from invasive isolates. Three (20%) community isolates were rifampin resistant and had a previously unreported mutation in the rpoB gene., Conclusions: In the outbreak community, Hia isolates from carriers were indistinguishable from the invasive Hia isolates. Overall, invasive Hia isolates from Alaska in 2018 were genetically similar. The rifampin resistance mutation is concerning as rifampin is the first-line medication for Hia prophylaxis., (Published by Oxford University Press for the Infectious Diseases Society of America 2021.)

Zika virus infection during pregnancy can cause serious birth defects of the brain and eyes, including intracranial calcifications, cerebral or cortical atrophy, chorioretinal abnormalities, and optic nerve abnormalities (1,2). The frequency of these Zika-associated brain and eye defects, based on data from the U.S. Zika Pregnancy and Infant Registry (USZPIR), has been previously reported in aggregate (3,4). This report describes the frequency of individual Zika-associated brain and eye defects among infants from pregnancies with laboratory evidence of confirmed or possible Zika virus infection. Among 6,799 live-born infants in USZPIR born during December 1, 2015-March 31, 2018, 4.6% had any Zika-associated birth defect; in a subgroup of pregnancies with a positive nucleic acid amplification test (NAAT) for Zika virus infection, the percentage was 6.1% of live-born infants. The brain and eye defects most frequently reported included microcephaly, corpus callosum abnormalities, intracranial calcification, abnormal cortical gyral patterns, ventriculomegaly, cerebral or cortical atrophy, chorioretinal abnormalities, and optic nerve abnormalities. Among infants with any Zika-associated birth defect, one third had more than one defect reported. Certain brain and eye defects in an infant might prompt suspicion of prenatal Zika virus infection. These findings can help target surveillance efforts to the most common brain and eye defects associated with Zika virus infection during pregnancy should a Zika virus outbreak reemerge, and might provide a signal to the reemergence of Zika virus, particularly in geographic regions without ongoing comprehensive Zika virus surveillance., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Amanda Elmore reports support from the Florida Birth Defects Registry, Surveillance, Intervention, and Referral to Services for Infants with Microcephaly or Other Adverse Outcomes linked with the Zika Virus in Florida. Jane Fornoff reports that she is vice-chair of the Illinois Department of Public Health’s Institutional Review Board. Nicole D. Longcore reports grant support from Epidemiology and Laboratory Capacity for Infectious Diseases. Amy E. Nance reports that the is co-chair for Communication and Health Promotion of the National Birth Defect Prevention Network. Brennan Martin reports being a member-at-large for the National Birth Defect Prevention Network (2019). No other potential conflicts of interest were disclosed.

Background: Between May and July 2018, 4 Haemophilus influenzae serotype a (Hia) infections occurred in a remote Alaska community. We performed a public health response to prevent further illness and understand Hia carriage., Methods: We collected oropharyngeal samples community-wide to evaluate baseline carriage. Risk factors were evaluated by interview. We offered prophylactic rifampin to individuals in contact with invasive Hia patients (contacts) and to all children aged <10 years. Oropharyngeal samples were collected again 8 weeks after rifampin distribution. Samples were tested using real-time polymerase chain reaction and culture., Results: At baseline, 4 of 27 (14.8%) contacts and 7 of 364 (1.9%) noncontacts (P < .01) carried Hia. Contacts aged <10 years were more likely to carry Hia at any timepoint (11/18 [61%]) compared to contacts aged ≥10 years (3/34 [8.8%]), noncontacts aged <10 years (2/139 [1.4%]), and noncontacts ≥10 years (6/276 [2.2%]) (P < .001 for all). Hia carriers were clustered in 9 households (7% of total households). At the household level, carriage was associated with households with ≥1 contact (prevalence ratio [PR], 5.6 [95% confidence interval {CI}, 1.3-21.6]), crowding (PR, 7.7 [95% CI, 1.1-199.5]), and ≥3 tobacco users (PR, 5.0 [95% CI, 1.2-19.6]). Elevated carriage prevalence persisted in contacts compared to noncontacts 8 weeks after rifampin distribution (6/25 [24%] contacts, 2/114 [1.8%] noncontacts; P < .001)., Conclusions: Hia carriage prevalence was significantly higher among contacts than noncontacts. Rifampin prophylaxis did not result in a reduction of Hia carriage prevalence in this community., (Published by Oxford University Press for the Infectious Diseases Society of America 2020.)

Following increases in reported cases of hepatitis A, we assessed the impact of hepatitis A vaccine in Alaska Native persons. During 1996-2018, only 6 cases of hepatitis A were identified, all in unvaccinated adults. Populations can be protected against hepatitis A by achieving sufficient vaccination coverage over time., (Published by Oxford University Press for the Infectious Diseases Society of America 2020.)

Large COVID-19 outbreaks have occurred in high-density workplaces, such as food processing facilities (1). Alaska's seafood processing industry attracts approximately 18,000 out-of-state workers annually (2). Many of the state's seafood processing facilities are located in remote areas with limited health care capacity. On March 23, 2020, the governor of Alaska issued a COVID-19 health mandate (HM10) to address health concerns related to the impending influx of workers amid the COVID-19 pandemic (3). HM10 required employers bringing critical infrastructure (essential) workers into Alaska to submit a Community Workforce Protective Plan.* On May 15, 2020, Appendix 1 was added to the mandate, which outlined specific requirements for seafood processors, to reduce the risk for transmission of SARS-CoV-2, the virus that causes COVID-19, in these high-density workplaces (4). These requirements included measures to prevent introduction of SARS-CoV-2 into the workplace, including testing of incoming workers and a 14-day entry quarantine before workers could enter nonquarantine residences. After 13 COVID-19 outbreaks in Alaska seafood processing facilities and on processing vessels during summer and early fall 2020, State of Alaska personnel and CDC field assignees reviewed the state's seafood processing-associated cases. Requirements were amended in November 2020 to address gaps in COVID-19 prevention. These revised requirements included restricting quarantine groups to ≤10 persons, pretransfer testing, and serial testing (5). Vaccination of this essential workforce is important (6); until high vaccination coverage rates are achieved, other mitigation strategies are needed in this high-risk setting. Updating industry guidance will be important as more information becomes available., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

The risk for invasive streptococcal infection has not been clearly quantified among persons experiencing homelessness (PEH). We compared the incidence of detected cases of invasive group A Streptococcus infection, group B Streptococcus infection, and Streptococcus pneumoniae (pneumococcal) infection among PEH with that among the general population in Anchorage, Alaska, USA, during 2002-2015. We used data from the Centers for Disease Control and Prevention's Arctic Investigations Program surveillance system, the US Census, and the Anchorage Point-in-Time count (a yearly census of PEH). We detected a disproportionately high incidence of invasive streptococcal disease in Anchorage among PEH. Compared with the general population, PEH were 53.3 times as likely to have invasive group A Streptococcus infection, 6.9 times as likely to have invasive group B Streptococcus infection, and 36.3 times as likely to have invasive pneumococcal infection. Infection control in shelters, pneumococcal vaccination, and infection monitoring could help protect the health of this vulnerable group.

We identified risk factors for any emm type group A streptococcal (GAS) colonization while investigating an invasive emm26.3 GAS outbreak among people experiencing homelessness in Alaska. Risk factors included upper extremity skin breakdown, sleeping outdoors, sharing blankets, and infrequent tooth brushing. Our results may help guide control efforts in future outbreaks.

Competing Interests: All authors have completed and submitted the ICMJE form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Background: In 2016, we detected an outbreak of group A Streptococcus (GAS) invasive infections among the estimated 1000 persons experiencing homelessness (PEH) in Anchorage, Alaska. We characterized the outbreak and implemented a mass antibiotic intervention at homeless service facilities., Methods: We identified cases through the Alaska GAS laboratory-based surveillance system. We conducted emm typing, antimicrobial susceptibility testing, and whole-genome sequencing on all invasive isolates and compared medical record data of patients infected with emm26.3 and other emm types. In February 2017, we offered PEH at 6 facilities in Anchorage a single dose of 1 g of azithromycin. We collected oropharyngeal and nonintact skin swabs on a subset of participants concurrent with the intervention and 4 weeks afterward., Results: From July 2016 through April 2017, we detected 42 invasive emm26.3 cases in Anchorage, 35 of which were in PEH. The emm26.3 isolates differed on average by only 2 single-nucleotide polymorphisms. Compared to other emm types, infection with emm26.3 was associated with cellulitis (odds ratio [OR], 2.5; P = .04) and necrotizing fasciitis (OR, 4.4; P = .02). We dispensed antibiotics to 391 PEH. Colonization with emm26.3 decreased from 4% of 277 at baseline to 1% of 287 at follow-up (P = .05). Invasive GAS incidence decreased from 1.5 cases per 1000 PEH/week in the 6 weeks prior to the intervention to 0.2 cases per 1000 PEH/week in the 6 weeks after (P = .01)., Conclusions: In an invasive GAS outbreak in PEH in Anchorage, mass antibiotic administration was temporally associated with reduced invasive disease cases and colonization prevalence.

During 1975-2012, CDC surveillance identified 1,680 trichinellosis cases in the United States with implicated food items; among these cases, 1,219 were attributed to consumption of raw or pork products, and 461 were attributed to nonpork products. Although trichinellosis in the United States has historically been associated with consumption of pork, multiple nonporcine species of wild game also are competent hosts for Trichinella spp. and have been collectively implicated in the majority of trichinellosis cases since the late 1990s (1-4) (Figure 1). During July 2016-May 2017, the Alaska Division of Public Health (ADPH) investigated two outbreaks of trichinellosis in the Norton Sound region associated with consumption of raw or undercooked walrus (Odobenus rosmarus) meat; five cases were identified in each of the two outbreaks. These were the first multiple-case outbreaks of walrus-associated trichinellosis in Alaska since 1992 (Figure 2). Health care providers should inquire about consumption of commercially prepared and personally harvested meats when evaluating suspected trichinellosis cases, especially in areas where consumption of wild game is commonplace.

Historically, Alaska experienced cyclic hepatitis A virus (HAV) epidemics, and the HAV rate among Alaska Native people was significantly higher than among other racial/ethnic groups. We evaluated the impact of universal childhood vaccination, initiated in 1996, on HAV epidemiology in Alaska by analyzing HAV cases reported to the State of Alaska. HAV incidence in all age groups declined 98.6% from 60.0/100,000 in 1972-1995 to 0.9/100,000 in 2002-2007. The largest decrease (99.9%) was in Alaska Native people, whose incidence (0.3) in 2002-2007 was lower than the overall U.S. 2007 rate (1.0). Among age groups, the decrease (99.8%) among children aged 0-14 years was the largest. Routine childhood vaccination has nearly eliminated HAV infection in Alaska., ((c) 2010 Elsevier Ltd. All rights reserved.)

Objective: The aim of this study was to summarize the Alaska experience in centralizing distribution of rabies postexposure prophylaxis (PEP)., Methods: Data were collected from standard treatment sheets used to track doses and notes related to the exposure investigations., Results: From 2002 to 2007, the annual PEP usage rate was 2.2 per 100,000. Dogs were involved in 79% (68/86) of exposures. More than 50% (49/87) of people were exposed to a confirmed rabid animal; 31 (63%) of those people experienced nonbite exposures. Conversely, of the remaining 38 people exposed to an animal for which rabies status could not be confirmed, 35 (92%) sustained a bite or puncture. Direct and indirect costs averaged more than $3000 per person., Conclusions: The Alaska PEP usage rate was lower and the proportion of people exposed to confirmed rabid animals was higher when compared with other states. Alaska public health personnel invested significant time to ensure that PEP was only given when indicated. Without this gatekeeper approach, PEP would likely be administered at a much higher rate because medical facility staff lacks the time or ability to investigate animal exposures to rule out rabies. In Alaska, centralizing rabies PEP not only serves the patient's best interest, but it also makes efficient use of a potentially scarce product and supports rabies surveillance efforts by guaranteeing animals for testing. Such a program might not be feasible for a more populous state or jurisdiction, or areas with different rabies epizootiology; however, that may change if the supply of rabies biologics changes in the future.

Many hospitals and long-term care facilities in North America currently permit animals to visit with their patients; however, the development of relevant infection control and prevention policies has lagged, due in large part to the lack of scientific evidence regarding risks of patient infection associated with animal interaction. This report provides standard guidelines for animal-assisted interventions in health care facilities, taking into account the available evidence.

Objectives: Determining the public health burden from all dog bite injuries is hampered by the lack of comprehensive data sources. Available data in Alaska include the number of hospitalizations following dog bite injuries. While these data are skewed in severity, describing the epidemiology of dog bite injuries that resulted in hospitalization can suggest the overall community burden of these injuries., Study Design: Records of dog bite injuries reported to the Alaska Trauma Registry (ATR) were, Methods: Cases were defined as patients with E-code 906.0 in the ATR from 1991-2002 who had been hospitalized for at least 1 day., Results: From 1991-2002, 288 case-patients were hospitalized yielding an average annual rate of 3.9 per 100,000. The rate for Alaska Native people was 9.3 compared with a rate of 2.8 for non-Alaska Native people. The average days hospitalized was 4.6 for Alaska Native people compared with 2.5 for non-Alaska Native people. The highest rates occurred in more rural areas of northern and south-western Alaska., Conclusions: Alaska hospitalization rates from dog bite injuries were higher overall compared with the entire U.S. and suggest that a heavy burden exists from all dog bite injuries in the state. Alaska Native people were disproportionately affected. Further study into the circumstances surrounding the injuries is needed to fully understand the injury disparities and to adapt and implement prevention programs.

Two pediatricians in Anchorage observed that among patients of Samoan/Pacific Islander (S/PI) descent, bacterial wound cultures that grew Staphylococcus aureus often yielded methicillin-resistant isolates. The Alaska Section of Epidemiology performed chart reviews of patients that visited a large family practice clinic in Anchorage, Alaska, from 1996 through April 2000, and who were diagnosed with a skin infection. Eight of 204 patients were identified with culture-confirmed MRSA infections. Eighty percent (4 of 5) of S/PI patients had resistant isolates compared with 12% (4 of 34) of non S/PI patients (Yates corrected chi2 = 8.61, p-value = 0.003). Although subject to limitations, these data support similar findings documented by other studies that suggest MRSA infections disproportionately affect persons of S/PI origin. This study also suggests that it would be prudent to reduce the threshold of clinical suspicion for obtaining a skin culture among S/PI patients in Alaska, and avoid beta-lactam antibiotics until culture results are received.

Hospital antibiograms are compiled from facility microbiology laboratories and list specific organism-antimicrobial susceptibility combinations. Antibiograms can then be used by facility health care providers to guide choices of antimicrobials for treatment. For a specific time period, antibiograms from different facilities can be aggregated. These summaries are quick and easy to compile and can provide an overview of antimicrobial susceptibility in a region. We aggregated year 2002 antibiograms from nine Alaska hospitals with 50 or more beds. Data presented here suggest that a combined antibiogram can provide a rough summary of susceptibility estimates statewide, and demonstrate trends in decreasing susceptibility, as seen for methicillin-resistant Staphylococcus aureus. For future antibiogram summaries, other organisms can be added as they gain in relevance or concern, or other antimicrobials added as usage or resistance patterns change.

The results of liver function tests allowed local and state public health professionals in Alaska to accurately predict the magnitude of an outbreak of hepatitis A.