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M G Baker

Publications and source records attributed to M G Baker.

At least 19 recordsLinked to original sources
PubMed2006

Is the major increase in notified campylobacteriosis in New Zealand real?

Notifications of campylobacteriosis by New Zealand medical practitioners have increased steadily in the last two decades. To determine if this increase is real, as opposed to a surveillance artefact, we examined both available notification (1980-2003) and hospitalization data (1995-2003). The similarity in the temporal pattern of increasing hospitalizations for campylobacteriosis, with that of notifications, is suggestive that this increase is indeed real. Although some risk factors for this disease have been identified (e.g. uncooked poultry consumption) it is unclear what the likely causes of the increasing rates are. The overall disease burden is also high compared with other developed countries (an annual notification rate of 396 cases per 100000 population in 2003), with highest rates in children aged 1-4 years, males, Europeans, and those living in urban areas. Given the large disease burden, further research and intervention studies should be public health priorities in this country.

Adolescent↗
PubMed2006

A recurring salmonellosis epidemic in New Zealand linked to contact with sheep.

One strain of Salmonella Brandenburg began causing large numbers of human infections in New Zealand in 1998. We investigated the emergence of this strain using combined notification and laboratory data on human and animal disease and a case-control study. S. Brandenburg infection in humans was characterized by spring peaks and high rates in the southern half of the South Island. This epidemic pattern followed very closely that seen in sheep. The case-control study found that infection was significantly associated with occupational contact with sheep and having a household member who had occupational contact with sheep, during the 3 days prior to illness or interview. We conclude that S. Brandenburg has become established as a zoonotic disease in New Zealand. Preventing infection requires control of the epidemic in sheep through vaccination, changes in farm management practices, and promotion of hand washing and other precautions to protect farmers and their families.

Adolescent↗
PubMed2006

Continuing Mycobacterium bovis transmission from animals to humans in New Zealand.

New Zealand has a large reservoir of Mycobacterium bovis infection in wild and farmed animals. This study aimed to assess the extent of human infection with this organism and the potential contribution of these animal sources. Combined epidemiological and laboratory investigation of human tuberculosis cases over the period 1995-2002 showed that M. bovis accounted for 2.7% (54/1997) of laboratory-confirmed human tuberculosis cases, a rate of 0.2/100,000 population. M. bovis isolates from humans (23) were typed using restriction endonuclease analysis (REA) and compared with isolates from wild and domestic animals (2600). Fourteen (61%) of the human isolates had REA patterns that were identical to patterns for isolates from cattle, deer, possums, ferrets, pigs, and occasionally cats. These results suggest a low level of ongoing M. bovis transmission from animal reservoirs to humans in New Zealand.

Adult↗
PubMed2005

The occurrence of Campylobacter subtypes in environmental reservoirs and potential transmission routes.

AIM: To identify potential reservoirs and transmission routes of human pathogenic Campylobacter spp. METHODS AND RESULTS: An enrichment PCR method for the detection and identification of Campylobacter jejuni and/or Campylobacter coli in faecal, food and river water samples was applied to 1450 samples of 12 matrix types obtained from a defined geographical area. PCR-positive samples were cultured to yield isolates for typing, and the data for 616 C. jejuni isolates obtained. Serotyping and SmaI macrorestriction profiling using pulsed field gel electrophoresis revealed a high level of diversity within the isolates from each matrix. Campylobacter jejuni and C. coli subtypes indistinguishable from those obtained from human cases were detected in most of the matrices examined. No Campylobacter isolates were isolated from possum faeces. CONCLUSIONS: Ten of the 12 matrices examined may be involved in the transmission of human campylobacteriosis as they contained Campylobacter subtypes also isolated from clinical cases. SIGNIFICANCE AND IMPACT OF THE STUDY: Results indicate that, for this rural population, a range of potential transmission routes that could lead to campylobacteriosis exist. Their relative importance needs to be assessed from an exposure assessment standpoint.

Animals↗
PubMed2004

Education in the broader sense.

Education is the key element in medical science. It is generally divided into pre-graduate, postgraduate and continuing medical education, with the physician as the main target. It usually covers aetiology, diagnosis, treatment, prognosis, outcome and long-term effects. Neurology is a large field in medical science, focusing on diseases of the brain, the spinal cord, the peripheral nerves and muscles. They tend to be chronic and, often progressive, leading to long-term disability and handicap for the individual, frequently associated with personal, social and emotional consequences. In the time span of a patient with a neurological disease, interaction with physicians is important and often vital, but interaction with other health groups and relatives or other caregivers is longer and more intensive. The knowledge and experience of the patient and caregiver is equally important, in that an informed patient or caregiver is more likely to participate actively and be of greater benefit in disease management. This paper promotes the concept that education in neurology should be integrated to include the physicians and other professionals as well as patients, caregivers and public. A broader awareness of neurological diseases will draw support and improve the approach of society to the provision of resources and management of these illnesses, as well as public attitude towards the symptoms and to those who live with them. Two bodies have collaborated in writing this article: the education committee of the EFNS and the EFNA.

Caregivers↗
PubMed2002

Changing epidemiology of human leptospirosis in New Zealand.

The objective was to describe the current epidemiology and trends in New Zealand human leptospirosis, using descriptive epidemiology of laboratory surveillance and disease notification data, 1990-8. The annual incidence of human leptospirosis in New Zealand 1990-8 was 44 per 100,000. Incidence was highest among meat processing workers (163.5/100,000), livestock farm workers (91.7), and forestry-related workers (24.1). The most commonly detected serovars were Leptospira borgpetersenii serovar (sv.) hardjo (hardjobovis) (46.1%), L. interrogans sv. pomona (24.4%) and L. borgpetersenii sv. ballum (11.9%). The annual incidence of leptospirosis declined from 5.7/100,000 in 1990-2 to 2.9/100,000 in 1996-8. Incidence of L. borgpetersenii sv. hardjo and L. interrogans sv. pomona infection declined, while incidence of L. borgpetersenii sv. ballum infection increased. The incidence of human leptospirosis in New Zealand remains high for a temperate developed country. Increasing L. borgpetersenii sv. ballum case numbers suggest changing transmission patterns via direct or indirect exposure to contaminated surface water. Targeted and evaluated disease control programmes should be renewed.

Adolescent↗
PubMed2001

A 10-year serogroup B meningococcal disease epidemic in New Zealand: descriptive epidemiology, 1991-2000.

OBJECTIVE: New Zealand has experienced an epidemic of meningococcal disease since 1991. This paper describes the characteristics of this epidemic during its first 10 years (1991-2000), current control measures, and potential future interventions. METHODOLOGY: Meningococcal disease surveillance in New Zealand uses combined notification and laboratory data. Population census data from 1991 and 1996 were used to calculate disease rates. RESULTS: The annual incidence of meningococcal disease increased from 53 cases (1.6 per 100 000 population) in the pre-epidemic year of 1990 to a peak of 613 (16.9 per 100000) in 1997, followed by consistently raised rates. Over the 1996-2000 period, there was an average of 502 cases per year (13.9 per 100 000). The epidemic has resulted in 3547 cases since 1991 approximately 3000 in excess of the number expected based on pre-epidemic disease incidence. Of the total cases, 158 (4.5%) were fatal. A disproportionately large number of cases have been in Maori and Pacific Islands children in the northern part of the North Island of New Zealand. Since 1991, the epidemic has increasingly been dominated by serogroup B meningococci with subtype P1.7b,4, which by 2000 accounted for 84.6% of all cases for whom this testing was carried out. The majority of these organisms were characterised as B:4:P1.7b,4. CONCLUSION: Meningococcal disease rates are likely to remain elevated in New Zealand for at least several more years. A vaccine which could induce immunity to the P1.7b,4 PorA subtype may have a role in controlling this epidemic. Efforts are underway to obtain and trial such a vaccine. Measures are also underway to reduce overcrowded living conditions which are contributing to the epidemic. Early recognition and antibiotic treatment of cases improves outcomes and should continue to be promoted. Integrated notification and laboratory-based surveillance of meningococcal disease provides relatively complete surveillance of this disease in New Zealand and has supported the development of public health interventions.

Adolescent↗
PubMed2000

Estimated number of cases of foodborne infectious disease in New Zealand.

AIMS: To estimate the annual number of cases of infectious intestinal disease caused by foodborne pathogens in New Zealand and estimate the impact of these diseases in terms of days lost to illness. METHODS: Incidence of foodborne diseases were derived from data from infectious disease surveillance and hospital sources, and estimates of unreported illnesses using published population based studies. RESULTS: The estimated number of cases of foodborne infectious disease is approximately 119 000 per year, including 19 000 general practitioner visits, 400 hospital admissions, 22 cases of long term illness and two deaths. It is estimated that the number of cases of potentially foodborne infectious disease is approximately 199 000. Total number of cases of all infectious intestinal disease could be as high as 823 000. Days of lost production and leisure time activities lost to foodborne infectious disease are estimated as approximately 497 000. CONCLUSION: Foodborne infectious diseases represent a major public health burden in terms of the number of cases and days lost to illness.

Disease Outbreaks↗
PubMed2000

Economic cost to New Zealand of foodborne infectious disease.

AIMS: To estimate the annual economic cost to New Zealand of foodborne infectious disease. METHODS: Annual incidence rates were combined with unit cost data to derive estimates of the annual economic cost to society of each foodborne infectious disease. Market prices and wages were used as proxies for the unit costs of resource utilisations. A decision analytic model was developed to estimate the costs of each disease and to undertake sensitivity analysis. RESULTS: There are an estimated 119 320 episodes of foodborne infectious disease per year in New Zealand (3241 per 100 000 population). The total cost of these cases was $55.1 million ($462 per case) made up of direct medical costs of $2.1 million, direct non-medical costs of $0.2 million, indirect cost of lost productivity of $48.1 million, and intangible cost of loss of life of $4.7 million. Campylobacteriosis generated most of the costs. Lost productivity was the major cost component for all diseases. The total cost of potentially foodborne infectious disease was estimated to be $88.8 million. Broad estimates of additional costs due to cases of infectious intestinal diseases caused by non-foodborne pathogens or for which no pathogen is identified could raise the cost to $215.7 million. CONCLUSION: The findings imply that resources of $55 million could be devoted to prevention of foodborne infectious disease. Efforts should focus on lowering the incidence of campylobacteriosis as this disease accounts for most of foodborne illness costs.

Disease Outbreaks↗
PubMed1999

Hepatitis B carriage explains the excess rate of hepatocellular carcinoma for Maori, Pacific Island and Asian people compared to Europeans in New Zealand.

BACKGROUND: The aim of this research was to determine the hepatitis B surface antigen (HBsAg) carrier prevalence among cases of hepatocellular carcinoma (HCC), and the population attributable risk of HBsAg carriage for HCC, by ethnicity in New Zealand. METHODS: The hospital notes of HCC cases registered with the New Zealand Cancer Registry, for the years 1987-1994 inclusive, were viewed to determine the HBsAg status. Results The HBsAg status was determined for 193 cases of HCC. The HBsAg carrier prevalence for non-Europeans with HCC was markedly higher than that for Europeans, being 76.7% for Maori, 80.0% for Pacific Island people, and 88.5% for Asians, compared to 6.0% for Europeans. In addition to the effect of ethnicity, HCC cases aged <60 years were more likely to be HBsAg carriers than those aged > or = 60 years. The estimated population attributable risk of HBsAg for HCC, within each ethnic group, was only marginally less than the HBsAg prevalence due to the high relative risk of HBsAg carriage for HCC. The standardized incidence rate ratios of HCC for Maori, Pacific Island people and Asians compared to Europeans were 9.6, 20.4, and 22.3, respectively. Hepatocellular carcinoma attributable to HBsAg carriage explained 79%, 83%, and 92% of the excess standardized rate of HCC, compared to Europeans, for Maori, Pacific Island people, and Asians, respectively. Conclusions The HBsAg carrier prevalence in non-European cases of HCC in New Zealand is between 75% and 90%. HBsAg carriage explains the majority of the excess rate of HCC in non-Europeans compared to Europeans in New Zealand.

Adolescent↗
PubMed1998

From the moment of diagnosis.

The population is living longer today, and with old age comes frailty and more long-term neurological illnesses. Parkinson's disease will become more common, and to support community care better, funds will need to be shifted to this sector. There are a number of Parkinson's disease societies in Europe, and a working group on this disease will be meeting in Geneva in May 1998. This is therefore a time for closer collaboration with many organisations, which will result in increased awareness and thereby an improvement in quality of life.

Europe↗
PubMed1998

New Zealand epidemic of meningococcal disease identified by a strain with phenotype B:4:P1.4.

New Zealand is experiencing an epidemic of serogroup B meningococcal disease, which has taken the rate of disease from an average of 1.5/100,000 population in the preepidemic years of 1989 and 1990 to 14.0/100,000 in 1996. Sterile-site isolates of Neisseria meningitidis from cases of invasive disease have been phenotypically characterized by serogrouping, serotyping, and serosubtyping, revealing the involvement of a strain with phenotype B:4:P1.4. Macrorestriction analysis using pulsed-field gel electrophoresis on 667 meningococci isolated from cases during the epidemic has identified the clonal relationship of meningococci expressing the PorA P1.4 antigen. Multilocus enzyme electrophoresis has shown the epidemic strain B:4:P1.4 to belong to lineage III. The recorded characteristics of New Zealand's epidemic are consistent with previous serogroup B epidemics in other parts of the world.

Adolescent↗
PubMed1997

Acute gastroenteritis diagnostic practices of New Zealand general practitioners.

AIMS: A sample of New Zealand general practitioners was surveyed to determine the laboratory referral practices of general practitioners for patients with acute gastroenteritis, with particular reference to viral gastroenteritis. METHODS: A mail questionnaire was sent to 209 general practitioners throughout New Zealand. RESULTS: The most important criteria for laboratory referral of a diarrhoeal specimen were prolonged duration of illness, presence of blood in the stool, a recent history of overseas travel, tramping or camping, shellfish consumption, or if the patient worked in the food, child care, or health care industries. Most general practitioners reported that they would refer diarrhoeal specimens from less than 25% of their patients with acute gastroenteritis. Requests for testing for viruses other than rotavirus were rare. CONCLUSION: The viral agents causing acute gastroenteritis were less likely to receive laboratory confirmation than other causes of gastroenteritis. On the basis of current laboratory investigation practices of general practitioners, foodborne viral gastroenteritis outbreaks are unlikely to be identified as such in New Zealand.

Acute Disease↗
PubMed1996

The epidemiology of imported malaria in New Zealand 1980-92.

AIM: To describe the epidemiology of imported malaria in New Zealand for the years 1980-92. METHODS: Malaria cases were identified from notification data and hospital discharge data. Records were matched using the discharge date, area health board, age, sex and ethnicity of the case, producing an electronic database, which was analysed. RESULTS: During 1980-92, a total of 867 cases of malaria were identified, an average of 67 per year. Only 43% of hospitalised cases were notified. There was a predominance of male cases (69.9%) and of cases aged 20-39 (60.2%). Over 60% of cases were European. Three cases (0.3%) were fatal. The leading source regions were Papua New Guinea, Solomon Islands and Vanuatu. South East Asia, South Asia (India), East Asia (China) and Africa were source regions of more moderate importance. The species of malaria was recorded in 80% of cases of which Plasmodium vivax malaria was the most common (67.5% of cases), with P falciparum accounting for 22.5% of cases. While the rate of malaria among arrivals to New Zealand declined between 1980 and 1992 there was a significant rise in the incidence of P falciparum over this period. CONCLUSIONS: The New Zealanders most at risk are essentially those travelling to high risk areas. There is a need to encourage the use of chemoprophylaxis for travellers to such regions-notably Vanuatu, Solomon Islands, and Papua New Guinea. Medical practitioners should notify all cases of malaria to support effective surveillance of this disease.

Adolescent↗
PubMed1993

The cortical topography of temporal lobe hypometabolism in early Alzheimer's disease.

Alzheimer's disease (AD) is characterized by a pathological process with specific predilection for association neocortex and the mesial temporal lobes. Recently developed high-resolution positron emission tomographs (PET) are able to quantitate regional cerebral metabolic rates for glucose (rCMRglc) in these brain regions and map the distribution of the metabolic consequences of Alzheimer pathology. In order to evaluate the relative involvement of mesial and neocortical temporal lobe brain regions in AD, we studied 22 AD patients, 11 of whom were mildly demented and 11 of whom were moderately demented in comparison to 8 age-matched control subjects. We used a PET instrument with 2.6 mm in-plane resolution and quantitated rCMRglc in anterior, middle, and posterior temporal neocortex, visual association cortex, primary visual cortex, and mesial temporal cortex. Although the moderately demented AD patients showed significantly lower metabolic rates than controls in visual association cortex and all temporal lobe regions except right anterior temporal neocortex, the mildly demented patients were different from the controls in only middle temporal neocortex. Considerable variability was found in the relative involvement of mesial temporal lobes and temporal neocortex in the AD patients, however, as shown by greater variance of a ratio of mesial temporal lobe rCMRglc to temporal neocortical rCMRglc (MES/NEO ratio) in the AD patients than the controls. A series of stepwise multiple regressions showed that this ratio was related to patient cognitive symptomatology, with more severely memory-impaired patients showing lower MES/NEO ratios, while patients with visuospatial disturbances showed higher MES/NEO ratios. In addition, the only biological variable that was related to this ratio was patient age, with older patients showing lower MES/NEO ratios. These results indicate that mesial temporal lobe structures are not invariably the earliest nor the most severely metabolically involved brain regions in AD and that the relative involvement of the mesial and neocortical temporal lobe is related to the patient's cognitive symptoms and age.

Aged↗
PubMed1993

Cognitive correlates of regional cerebral blood flow in Alzheimer's disease.

OBJECTIVE: To study the relationship between relative regional cerebral blood flow (rCBF) and performance on a variety of neuropsychological tests in a group of subjects with Alzheimer's disease. DESIGN: Analysis of the relationship between relative rCBF and neuropsychological performance using stepwise multiple regressions and Pearson Product-Moment Correlation coefficients. SETTING: University dementia clinic and research laboratory. PARTICIPANTS: Twelve mildly demented patients with Alzheimer's disease (Mini-Mental State examination [MMSE] scores, 24 to 29; age, 56 to 78 years); 38 moderately demented patients with Alzheimer's disease (MMSE scores, 0 to 23; age, 59 to 86 years); and eight normal control subjects (MMSE scores, 27 to 30; age, 61 to 79 years). MAIN OUTCOME MEASURES: Single photon emission computed tomography and the blood flow tracer N-isopropyl-p-iodoamphetamine iodine 123 were used to measure relative rCBF. Cognitive performance was assessed by grouping neuropsychological tests into clusters reflecting frontal lobe abilities, perseveration, memory, and visuoconstructive abilities. RESULTS: While MMSE score was a significant (P < .05) predictor of visuoconstruction, frontal lobe, and memory cluster scores, relative rCBF was a weaker predictor of neuropsychological performance, with only right orbitofrontal relative rCBF emerging as a significant (P < .05) predictor of the frontal cluster score and right parietal relative rCBF as a significant (P < .05) predictor of the visuoconstruction cluster score. CONCLUSIONS: These results support our a priori grouping of neuropsychological tests into frontal and visuoconstruction clusters and suggest that these two clusters are good measures of frontal and parietal lobe function, respectively.

Aged↗