Risk to consumers from mercury in Pacific cod (Gadus macrocephalus) from the Aleutians: fish age and size effects

While there has been considerable attention devoted to the risks to high level consumers from mercury in freshwater fish, relatively little attention has been devoted to saltwater fish. Although the U.S. Food and Drug Administration has issued advisories based on mercury for four saltwater species or groups of fish, there are few data on mercury levels generally, or on the risk these levels pose to the fish themselves or to consumers of marine fish. We examined total mercury levels in liver and muscle of Pacific cod (Gadus macrocephalus) collected from the northern Pacific and Bering Sea waters around Nikolski, Amchitka, and Kiska Islands in the Aleutian Chain (Alaska). We were interested in whether there were differences in mercury levels as a function of location, weight, length, and age of the fish, and what risk mercury posed to the food chain, including people. Fish were aged by examining otoliths, and we measured selenium because of its reported protective effects against mercury. Regression models indicated that 27% of the variation in levels of mercury was due to tissue examined and age, while 67% of the variation in levels of selenium was due to tissue, length, and age. Mercury levels were significantly higher in the muscle than the liver, and the reverse was true for selenium. Mercury levels were negatively correlated with selenium levels, and positively correlated with length, weight, and age. There were no gender differences in mercury or selenium levels. The mean levels of mercury in muscle (0.17 ppm wet weight) are within the range known to cause adverse effects in sensitive birds and mammals. Only 4% of the Pacific cod samples had mercury levels above 0.5 ppm, the action level promulgated by many states and countries, and none were above the 1 ppm action level of the U.S. FDA.     

Lead, mercury, cadmium, chromium, and arsenic levels in eggs, feathers, and tissues of Canada geese of the New Jersey Meadowlands

The New Jersey Meadowlands are located within the heavily urbanized New York/New Jersey Harbor Estuary and have been subject to contamination due to effluent and runoff from industry, traffic, and homes along the Hackensack River and nearby waterways. These extensive wetlands, though heavily impacted by development and pollution, support a wide array of bird and other wildlife species. Persistent contaminants may pose threats to birds in these habitats, affecting reproduction, egg hatchability, nestling survival, and neurobehavioral development. Metals of concern in the Meadowlands include arsenic, cadmium, chromium, lead, and mercury. These metals were analyzed in eggs, feathers, muscle, and liver of Canada geese (Branta canadensis) breeding in four wetland sites. We sampled geese collected during control culling (n=26) and collected eggs from goose nests (n=34). Levels of arsenic were below the minimum quantification level (MQL) in most samples, and cadmium and mercury were low in all tissues sampled. Chromium levels were high in feather samples. Mercury levels in eggs of Canada geese, an almost exclusively herbivorous species, were lower (mean ±SE 4.29±0.30 μg/g wet weight) than in eggs of omnivorous mallards (Anas platyrhynchos), and insectivorous red-winged blackbirds (Agelaius phoeniceus) and marsh wrens (Cistothorus palustris) from the Meadowlands, consistent with trophic level differences. However, lead levels were higher in the goose eggs (161±36.7 ng/g) than in the other species. Geese also had higher levels of lead in feathers (1910±386 ng/g) than those seen in Meadowlands passerines. By contrast, muscle and liver lead levels were within the range reported in waterfowl elsewhere, possibly a reflection of metal sequestration in eggs and feathers. Elevated lead levels may be the result of sediment ingestion or ingestion of lead shot and sinkers. Finally, lead levels in goose liver (249±44.7 ng/g) and eggs (161±36.7 ng/g) may pose a risk if consumed frequently by humans. Mill Creek, the site with the most documented prior contamination, had significantly elevated cadmium, chromium, mercury, and lead in goose tissues.     

Fishing, fish consumption, and knowledge about advisories in college students and others in central New Jersey

Risks to humans and other organisms from consuming fish have become a national concern. Over the past 3 years there have been a number of national advisories regarding saltwater fish. Although information on fishing, consumption patterns, and public knowledge about advisories has been examined for at-risk populations, there is little information about the latter for a general population. Overall knowledge about advisories, ratings for information about the risks and benefits of eating fish, and the relationship between fishing, consumption patterns, and knowledge about advisories was examined in a sample of 180 college students and others residing in central New Jersey, USA. The null hypothesis of no differences in fishing, consumption, and knowledge about advisories as a function of age, gender, ethnicity, and education was tested. A significantly higher proportion of men fished compared to women, and significantly fewer Blacks and Asians fished than did Whites or Hispanics. More Asians who fished did so in salt water, compared to others. There were no gender differences in consumption patterns, and few age or ethnic differences, mainly due to low sample sizes in some ethnic groups. Significantly fewer young people and fewer Asians ate fish compared to others. Overall, more people knew about the benefits of eating fish than the risks. Half as many people had heard about advisories concerning tuna, and less than a third knew about advisories concerning shark and swordfish than had heard general warnings. There were no gender differences in knowing about advisories, but there were several ethnic differences: a lower percentage of Asians generally knew that there were advisories, and fewer Blacks knew that there were benefits from eating fish than others. People in the age group 21-45 years were less aware of both the benefits and the risks from eating fish compared to older people. These data suggest that risk managers need to target younger people for information about the risks and benefits of consuming fish, particularly given that this is the population that will become pregnant over the next few years. Contrary to some previous research, subjects trusted family, friends, and other fishermen less for knowledge about the risks and benefits of fish consumption than other sources, such as doctors, governmental officials, and university professors. Even with this limited sample size, it is clear that people have heard more about the benefits of fish consumption than the risks, and a relatively low percentage have heard about the recent US Food and Drug Administration warnings about swordfish and shark.     

Fishing, fish consumption, and awareness about warnings in a university community in central New Jersey in 2007, and comparisons with 2004

Fish are a healthy source of protein, but the risks from consuming fish have become a national concern. Over the past 7 years, there have been a number of national advisories regarding saltwater fish. Fish consumption patterns and public knowledge about advisories and warnings have been examined for at-risk populations, but there is little information about the latter for a general population, or of temporal trends in such information acquisition. Information about the benefits and health risks of consuming fish, health warnings from the New Jersey Department of Environmental Protection and the Food and Drug Administration, belief in these warnings, and trust in different sources of information were examined in a sample of 460 people within a university community in central New Jersey in 2007. The null hypothesis of no differences in fishing, consumption, and knowledge about advisories as a function of age, gender, ethnicity, and education was tested. In 2007, only 30% of the study population fished, and 83% of the study population ate fish, either commercial or self-caught. There were differences in fishing behavior, consumption patterns, and awareness of advisories as a function of gender, ethnicity, age, and education. Most notably, nearly twice as many men as women fished, Whites fished more and Blacks and Indian/Pakistanis fished less than other ethnic groups, and people aged 23-35 fished more than did others. About 8% of fish meals were from self-caught fish, 32% were eaten in restaurants, and 60% were of fish bought in stores and cooked at home. Men ate more meals of self-caught fish than did females, and Asians ate more meals of fish in restaurants, and Blacks ate more meals of store-bought fish than other ethnic groups. The total number of fish meals consumed per month increased significantly with age. Overall, more people had heard about the benefits (92%) than the risks (78%) of fish consumption. When asked whom they trust for information about health benefits and risks from eating fish, doctors were rated the highest, followed by professors; friends and fishermen were rated the lowest. We then examined whether there were any changes from 2004 to 2007 in the knowledge of the health benefits and warnings about fish consumption, and the trustworthiness of different sources of information. In other words, have communication efforts of the state and federal agencies resulted in any appreciable increase in overall awareness of the benefits or risks of fish consumption. The greatest change in the parameters examined from 2004 to 2007 was an overall decrease in fish consumption from an average of 7.9 meals per month in 2004 to about six meals per month in 2007. This suggests that the unintended effect of some of the warnings and advisories is to decrease overall fish consumption, rather than to switch from fish species with high levels of contaminants to those with low levels.     

Metal levels in eggs of common terns (Sterna hirundo) in New Jersey: temporal trends from 1971 to 2002

Managers and public policy makers require information on the status of and trends in contaminant levels in organisms to assess ecosystem health. Seabirds are excellent bioindicators because they are long-lived, feed at different trophic levels, and are at the top of the food chain, and many are abundant and widely distributed. They can reveal spatial or temporal trends in contaminant levels. In this paper, we examine temporal trends in the levels of cadmium, chromium, lead, manganese, mercury, and selenium in eggs from common terns (Sterna hirundo) nesting on several salt marsh islands in Barnegat Bay, New Jersey. We test the null hypothesis that there are no temporal differences in levels of cadmium, lead, and mercury from 1971 to 2002 and in chromium, manganese, and selenium from 1992 to 2002. Arsenic was also analyzed in recent years. Levels were highest for manganese, followed by selenium, mercury, arsenic, lead, chromium, and cadmium. The eggs of Barnegat Bay common terns show a decline in levels of cadmium, chromium, and lead. Mercury declined from 1971 to 1982, increased dramatically in 1999, and declined thereafter. Manganese, an essential element, showed a decline (except for 2001), and selenium declined initially, but then remained stable. The data indicate that common terns can serve as useful bioindicators of temporal trends in exposure and that some of the metals of concern in estuarine environments (lead, cadmium) have declined over the past 30 years, although mercury levels are higher than in the early 1980s. The spike in 1999 is unexplained.     

Mercury and polychlorinated biphenyls in Asian market fish: A response to results from mercury biomonitoring in New York City

In 2004, the New York City (NYC) Health and Nutrition Examination Survey measured the highest blood mercury levels in Asian and foreign-born Chinese demographic groups. Fish consumption was the strongest predictor of exposure. The survey did not inquire about consumption of individual species, and subsequent visits to fish markets serving the Asian community suggested that many popular species lack contaminant data. Our objective was to supplement existing information on contaminants in commercial fish by collecting data on species present in markets serving the Asian community.We measured total mercury and the sum of 101 polychlorinated biphenyl (PCB) congeners in 282 individual specimens of 19 species or products from retail fish markets in Chinese neighborhoods in NYC. Species were selected based on their volume in the market, and an absence or insufficiency of national data on mercury levels. PCBs were measured because they are also contaminants of concern. All measurements were made on a wet weight basis on whole fillets (with skin) or products (drained of liquid). Mean mercury levels ranged from below the limit of detection (0.004 μg/g) in tilapia to 0.229 μg/g in tilefish. The highest mercury level (1.150 μg/g) was measured in a tilefish specimen, and mercury levels in tilefish increased with the specimen size. Mean PCB levels ranged from 1 ng/g in red snapper to 98 ng/g in buffalo carp. The highest PCB levels were measured in a buffalo carp (469 ng/g) and a yellow croaker (495 ng/g). Species-specific differences in PCB levels accounted for only 6.3% of total variability, in contrast with 39.2% for mercury.Although we did not measure high mean mercury levels in the species we sampled, frequent consumption of fish with low to moderate levels can also elevate blood mercury. The data we collected can be used to guide fish consumption in Asian communities. However, risk-benefit trade-offs also need to be considered.     

Metal levels in flathead sole (Hippoglossoides elassodon) and great sculpin (Myoxocephalus polyacanthocephalus) from Adak Island, Alaska: potential risk to predators and fishermen

Increasingly there is a need to assess the contaminant levels in fish as indicators of the health and well-being of both the fish and their consumers, including humans. This paper examines the levels of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in the kidney, liver, and muscle of great sculpin and flathead sole from Adak Island in the Aleutian Islands, Alaska. Both species are consumed by the local Aleuts and others. There were significant differences in the levels of heavy metals as a function of tissue for both fish species; the liver of sculpin and sole generally had the highest levels of most metals, except for arsenic, lead, and selenium. Sole had significantly higher mean levels of arsenic in kidney (32,384 vs. 531 ppb, wet weight), liver (18,954 vs. 2532 ppb), and muscle (19,452 vs. 1343 ppb) than did sculpin. Sole also had higher mean levels of cadmium (230 vs. 63 ppb), lead (1236 vs. 48 ppb), mercury (150 vs. 107 ppb), and selenium (5215 vs. 1861 ppb) in kidney than did sculpin. There were significant correlations among weight and length measurements for both species. However, except for mercury, there were few significant correlations among tissue types for most metals. Only mercury and manganese levels were significantly correlated with size for sculpin (but not for sole). Levels of arsenic, lead, and mercury may pose a risk to predators that consume them, and arsenic and mercury may pose a risk to human consumers.     

New Jersey: a case study of the reduction in urban and suburban air pollution from the 1950s to 2010

Background: Air pollution has been a topic of intense concern and study for hundreds of years. During the second half of the 20th century, the United States implemented regulations and controls to reduce the levels of criteria air pollutants and achieve the National Ambient Air Quality Standards (NAAQS) for the protection of human health, while concurrently reducing the levels of toxic air pollutants.Objective: In this commentary we trace the changes in air pollution in New Jersey as a case study, demonstrating the impact of local, state, and federal strategies to control emissions of pollutants and pollutant precursors from the 1950s until today.Discussion: The original NAAQS (1970–1995) have been achieved, and significant progress has been made to achieve revised standards for ozone and particulate matter (PM) < 2.5 µm in aerodynamic diameter (PM_2.5) in New Jersey, which in the past was considered a highly polluted industrial state.Conclusions: Assuming no reversals on current regulations because of some major event or energy infrastructure disruption, outdoor air pollution reductions will continue to address health risks among specific segments of the general population affected by ozone/PM and pollution caused by neighborhood, local, and regional point and mobile sources.     

Geographic, seasonal and ontogenetic variation in cadmium and mercury concentrations in squid (Cephalopoda: Teuthoidea) from UK waters

Cadmium (Cd) and mercury (Hg) levels were measured in the tissue samples of two loliginid (Alloteuthis sp. and Loligo forbesi) and two ommastrephid (Todarodes sagittatus and Todaropsis eblanae) squid species collected from research cruise and fishery (market) samples in UK waters during 2004–05. Concentrations of Cd were generally higher in the ommastrephids, in all tissues except muscle. Hg concentrations were higher in T. sagittatus than in the loliginids. In L. forbesi, metal concentrations differed between tissues and also varied in relation to body size, geographic origin, and season. Cd levels decreased with increasing body size. This may be related to a shift in the diet with growth, since small L. forbesi feed on benthic invertebrates that have relatively high Cd concentrations, whereas larger individuals prey mainly on fish that have low Cd concentrations. Hg levels increased with body size, indicating its retention, and they were highest at the end of the spawning season and in squid from the English Channel and the Scottish West Coast. It is likely that the ambient concentration of Hg in seawater plays an important part in its accumulation in squid tissues. As it is a short-lived species, L. forbesi may therefore function as a bioindicator species for Hg contamination of the marine environment. Our results indicate that there is no significant danger to humans from consuming squid from UK waters.     

The Use of Risk Assessment to Predict Recurrent Maltreatment: A Classification and Regression Tree Analysis (CART)

Research has suggested that recurrent maltreatment may be best predicted by a combination of factors that vary across families. The present study set out to determine whether a pattern-centered analytic approach would better predict families at high risk for recurrence when compared to logistic regression methods. Archival data from substantiated investigations during 2003 were collected from a Connecticut Department of Children and Families county branch. Families (n = 244) with a substantiated index case were followed for 18 months to identify the presence of additional substantiated cases within the CPS system. Classification and Regression Tree (CART) analyses revealed that prior CPS involvement was the best predictor of recurrent maltreatment. Further, risk items that were associated with recurrence were different for families with and without previous CPS investigations. Families with only prior unsubstantiated CPS investigations and poor child visibility within the community were at high risk for recurrence. Families without prior CPS involvement that were not actively involved in case planning and had a history of domestic violence were at high risk for recurrence. These findings suggest that pattern-centered analyses may be a useful approach to informing site-specific predictors of maltreatment recurrence by creating clear decision points that delineate high risk subgroups.     

Toxicity of methylmercury,mercuric chloride,and lead in killifish (Fundulus heteroclitus) from Southampton,New York

We have previously found great differences in susceptibility to teratogenic effects of methylmercury (meHg) among batches of eggs produced by different females of Fundulus heteroclitus. In the present study we investigated the relationships of resistance to meHg by a batch of eggs with other parameters of resistance. There was a positive correlation between embryonic meHg resistance and HgCl₂ resistance, although HgCl₂ generally caused less severe defects at a given dose level. The batches that were more susceptible to meHg had a greater uptake of mercury than the more resistant batches. There was a negative correlation of meHg resistance and Pb resistance (as measured by a skeletal index hatching), however. There was a positive correlation of meHg resistance of embryos and the subsequent meHg resistance of larvae after hatching.     

Antibody responses correlate with antigen dose and in vivo protection for oil-adjuvanted,experimental furunculosis (Aeromonas salmonicida subsp. salmonicida) vaccines in Atlantic salmon (Salmo salar L.) and can be used for batch potency testing of vaccines

Salmon farming has increased dramatically over last thirty years and a key to the success is the introduction of protective vaccines. In Norway, almost 100% of all Atlantic salmon are vaccinated prior to sea transfer. This extensive use of vaccines demands use of a lot of resources in production and quality control of vaccines, and fish are now one of the most widely used laboratory animal species in Norway, since all batch testing today is performed by challenge experiments. With an increasing focus on the 3 R's (Replacement, Reduction and Refinement), new methods are needed.     

河南省鸡公山库蠓调查及其一新种：双翅目：蠓科

为了解豫鄂交界处鸡公山的蠓类分布情况，于1994年春进行了调查，共发现库蠓属蠓类10种，其中有一新种（幻影库蠓）。     

山东蚋科二新种及一疑义种记述(双翅目:蚋科)

笔者在整理采自山东泰山的标本中发现蚋属Simulium二新种———泰山门蚋Simulium(Montisimulium)taishanensesp .nov、山东纳蚋S .(Nevermannia)shandongensesp .nov和一疑义种AS .(Simulium)sp .A ,对其形态特征进行描述 ,并与近缘种进行比较。     

Risk of silicosis in cohorts of Chinese tin and tungsten miners, and pottery workers (I): an epidemiological study

BACKGROUND: Epidemiological evaluations of the risk of silicosis in relation to exposure to crystalline silica have raised the question of whether different types of silica dust exposures vary with respect to their ability to cause silicosis. The aim of this study is to compare the risk of silicosis among cohorts of silica dust-exposed Chinese tin miners, tungsten miners, and pottery workers and to assess whether gravimetric measurements of respirable silica dust sufficiently determine the risk of silicosis or whether other factors of exposure may play a significant role. METHODS: Cohorts were selected from 20 Chinese mines and potteries. Inclusion criteria were starting employment after January 1, 1950 and being employed for at least 1 year during 1960-1974 in one of the selected workplaces. Radiological follow-up for silicosis onset was from January 1, 1950 through December 31, 1994. Silicosis was assessed according to the Chinese radiological criteria for diagnosis of pneumoconiosis (as suspect, Stage I, II, or III). Exposure-response relationships were estimated for silicosis of Stage I or higher. Silica dust exposure was estimated in terms of cumulative total dust exposure, calculated from a workplace, job title, and calendar year exposure matrix, and individual occupational histories. Cumulative total dust exposure was converted in two steps into cumulative respirable dust exposure and cumulative respirable silica dust exposure using conversion factors estimated from side-by-side measurements conducted in 1988-89. RESULTS: The male cohorts included 4,028 tin miners, 14,427 tungsten miners, and 4,547 pottery workers who had similar onset of employment and duration of follow-up. For a given exposure level, the risk of silicosis was higher for the tin and tungsten than the pottery workers. CONCLUSION: The observed differences in the risk of silicosis among the three cohorts suggest that silica dust characteristics, in addition to cumulative respirable silica dust exposure, may affect the risk of silicosis.     

Temporal trends of mercury, cesium, potassium, selenium, and thallium in Arctic char (Salvelinus alpinus) from Lake Hazen, Nunavut, Canada: effects of trophic position, size, and age

Arctic char (Salvelinus alpinus L.), the top predator in High Arctic lakes, often is used as a bioindicator of Hg contamination in Arctic aquatic ecosystems. The present study investigated effects of trophic position, size, and age of Arctic char in Lake Hazen, the largest lake in the Canadian High Arctic (81 degrees 50'N, 70 degrees 25'W), on Hg bioaccumulation. In addition, several essential (Se, K) and nonessential elements (Tl, Cs) in char muscle tissue were examined to compare their behavior to that of Hg. Trophic position of Arctic char was identified by stable isotope (delta15N) signature. Temporal trends of Hg from seven sampling campaigns over a 16-year period (1990-2006) were investigated for the overall data and for one trophic class. Concentrations of Hg were not correlated with age but were positively related to fork length and trophic position. Large char with greater delta15N signatures (> 12 per thousand) had larger Hg concentrations (0.09-1.63 microg/g wet wt) than small char with smaller delta15N signatures (< 12 per thousand, 0.03-0.32 microg/g wet wt), indicating that Hg concentrations increased with trophic position. Nonessential Cs and Tl showed relationships to age, length, and trophic position similar to those of Hg, indicating their potential to bioaccumulate and biomagnify. Essential Se and K did not show these relationships. Concentrations of Hg were adjusted using delta15N, leading to less within-year variability and a more consistent temporal trend. The delta15N-adjusted trend showed no decline of Hg in Arctic char from Lake Hazen (1990-2006) in the overall data set and in the small morphotype. Trends for the same period before the adjustment were not significant for the overall data set, but a slight decrease was apparent in the small morphotype. The results confirm the need to consider trophic position and fish size when monitoring temporal trends of Hg, particularly for species with different morphotypes.     

Occupational exposure to Cr(VI): comparison between chromium levels in lymphocytes,erythrocytes, and urine

 The relationships between chromium (Cr) levels in lymphocytes, erythrocytes, urine, and ambient air were compared among 14 chrome-platers from a metallurgic plant in Bulgaria and two groups of local controls, one from the same heavily polluted industrial town as the chrome-platers (n=11) and one from a seaside resort town 100 km away (n=6). Among the chrome-platers, the Cr concentration in peripheral lymphocytes was positively correlated with total Cr and Cr(VI) levels in ambient air and with Cr excretion in urine. As compared to the controls, the chrome-platers had mean Cr levels in lymphocytes twice as high, in erythrocytes ninefold higher, and in urine fourfold to eightfold higher. Although Cr levels in urine and lymphocytes were similar between the two control groups, levels in erythrocytes were 3 times higher among subjects from the industrial area than among those from the seaside town. The study suggests that lymphocyte Cr could be a good indicator of the Cr body burden caused by high exposures to Cr(VI), such as in electroplating operations. In these conditions, erythrocyte Cr may be less useful, possibly owing to increased toxicity due to the high affinity of erythrocytes for Cr. However, when exposure is lower, such as in most environmental situations, erythrocyte Cr should provide a better and more sensitive index than lymphocyte Cr. By contrast, urinary Cr, which provides information on total Cr exposure, including Cr(III) from dietary and environmental sources, does not seem to be of value for studying occupational exposure to Cr(VI). Received: 22 September 1995/Accepted: 2 January 1996     

Polybrominated diphenyl ethers (PBDEs) concentration in soil from San Luis Potosi,Mexico: levels and ecological and human health risk characterization

The aim of this study was to assess the levels of polybrominated diphenyl ethers (PBDEs) in soils from the city of San Luis Potosi in Mexico and perform an ecological and human health risk characterization. In order to confirm the presence of PBDEs, outdoor surface soil samples were collected and the concentrations of PBDEs in urban, industrial, agricultural, and brick kiln industry areas were determined. The mean total PBDEs levels obtained in the study sites were 25.0 ± 39.5 μg/kg (geometric mean ± standard deviation) in the brick kiln industry zone; 34.5 ± 36.0 μg/kg in the urban zone; 8.00 ± 7.10 μg/kg in the industrial zone and 16.6 ± 15.3 μg/kg in the agricultural zone. The ecological and human health risk characterization showed relatively low-hazard quotient values. However, the moderately high PBDEs levels found in soils highlight the necessity to establish a systematic monitoring process for PBDEs in environmental and biological samples.     

Changing epidemiology of invasive Haemophilus influenzae in Ontario,Canada: Evidence for herd effects and strain replacement due to Hib vaccination

The epidemiology of invasive Haemophilus influenzae infections was evaluated in Ontario between 1989 and 2007 to assess the impact of the introduction of the conjugate H. influenzae serotype b (Hib) vaccine in the early 1990s on Hib and non-Hib serotypes in both vaccinated and unvaccinated cohorts as well as the possibility of “strain replacement” with non-vaccine H. influenzae strains. Data were collected by the provincial Public Health Laboratories-Toronto, Ontario Agency for Health Protection and Promotion, which performed almost all serotyping on invasive (blood, CSF, other sterile sites) H. influenzae strains isolated in the province during the study period. Temporal trends for Hib, other typeable strains, and non-typeable H. influenzae were evaluated by Poisson regression, controlling for the specimen submissions. Prior to infant Hib vaccination, the most commonly observed serotype was serotype b (64.9%). Subsequently, 70.3%, 13.6%, and 9.4% of isolates were non-typeable, serotype f, and serotype b, respectively. Infant Hib vaccination resulted in a decrease in Hib incidence in all age groups (pooled IRR 0.432) and marked increases of non-typeable and serotype f H. influenzae in children aged <5 years (IRR 2.4 and 3.0, respectively). Vaccination against Hib has altered the epidemiology of invasive H. influenzae infections in Ontario. Prevention of invasive Hib disease was observed in both vaccinated and unvaccinated age groups. Invasive H. influenzae infection now commonly presents as sepsis due to non-typeable H. influenzae in older individuals. However, strain replacement of Hib with serotype f and non-typeable strains in children under 5 years was documented.