Disease surveillance in rural communities is compromised by address geocoding uncertainty: a case study of campylobacteriosis

ABSTRACT: This study illustrates the impact of address geocoding uncertainty on rural estimates of reportable disease incidence using campylobacteriosis as an example. After all cases of campylobacteriosis notified from 1993 to 1997 had been geocoded, the minimum and maximum disease notification rates were calculated for rural and urban areas of New Zealand. The estimated maximum rural rates were four times higher than estimated minimum rural rates, whereas estimated minimum and maximum urban rates varied minimally. The impact of address geocoding on the estimation of disease notification rates across Public Health Service Regions showed considerable variation. The relative proportions of ungeocoded notifications to rural notifications ranged from 1.3:1 to 10.2:1, reflecting the range of uncertainty in estimated rural rates of campylobacteriosis. Unless the reliability of captured rural address data is improved significantly, disease surveillance systems will underestimate rural rates of disease and limit small area analyses.     

Marked campylobacteriosis decline after interventions aimed at poultry, New Zealand

Beginning in the 1980s, New Zealand experienced rising annual rates of campylobacteriosis that peaked in 2006. We analyzed notification, hospitalization, and other data to explore the 2007-2008 drop in campylobacteriosis incidence. Source attribution techniques based on genotyping of Campylobacter jejuni isolates from patients and environmental sources were also used to examine the decline. In 2008, the annual campylobacteriosis notification rate was 161.5/100,000 population, representing a 54% decline compared with the average annual rate of 353.8/100,000 for 2002-2006. A similar decline was seen for hospitalizations. Source attribution findings demonstrated a 74% (95% credible interval 49%-94%) reduction in the number of cases attributed to poultry. These reductions coincided with the introduction of a range of voluntary and regulatory interventions to reduce Campylobacter spp. contamination of poultry. The apparent success of these interventions may inform approaches other countries could consider to help control foodborne campylobacteriosis.     

The spatial and temporal determinants of campylobacteriosis notifications in New Zealand, 2001-2007

Despite recent improvements, New Zealand still has one of the highest per-capita incidence rates of campylobacteriosis in the world. To reduce the incidence, a thorough understanding of the epidemiology of infection is needed. This retrospective analysis of 36 000 notified human cases during a high-risk period between 2001 and 2007 explored the spatial and temporal determinants of Campylobacter notifications at a fine spatial scale in order to improve understanding of the complex epidemiology. Social deprivation was associated with a decreased risk of notification, whereas urban residence was associated with an increased risk. However, for young children rural residence was a risk factor. High dairy cattle density was associated with an increased risk of notification in two of the three regions investigated. Campylobacter notification patterns exhibit large temporal variations; however, few factors were associated with periods of increased risk, in particular temperature did not appear to drive the seasonality in campylobacteriosis.     

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.     

Campylobacteriosis in New Zealand: results of a case-control study.

STUDY OBJECTIVE: To identify and assess the contributions of major risk factors for campylobacteriosis in New Zealand. DESIGN: Case-control study. Home interviews were conducted over nine months using a standardised questionnaire to assess recent food consumption and other exposures. SETTING: Four centres in New Zealand with high notification rates of campylobacter infections--Auckland, Hamilton, Wellington, and Christchurch. PARTICIPANTS: Case patients were 621 people notified between 1 June 1994 and 28 February 1995 as having campylobacter infection. Control subjects were selected randomly from telephone directories, and were matched 1:1 with case patients in relation to sex, age group, and home telephone prefix. RESULTS: Risk of campylobacteriosis was strongly associated with recent consumption of raw or undercooked chicken (matched odds ratio 4.52, 95% confidence interval 2.88, 7.10). There was also an increased risk with chicken eaten in restaurants (matched odds ratio 3.85; 2.52, 5.88). Recent consumption of baked or roasted chicken seemed to be protective. Campylobacteriosis was also associated with recent overseas travel, rainwater as a source of water at home, consumption of raw dairy products, and contact with puppies and cattle, particularly calves. CONCLUSIONS: Improperly cooked chicken seems to be associated with a large proportion of campylobacteriosis in New Zealand. Thorough cooking of chicken in homes and restaurants could reduce considerably the incidence of this disease.     

Large-scale freshwater microbiological study: rationale, results and risks

A fifteen-month fortnightly survey of microbial health risk indicators and pathogens has been carried out at 25 freshwater recreational and water supply sites distributed throughout New Zealand, for: E. coli, Clostridium perfringens spores, F-RNA bacteriophage, somatic coliphage, human enteroviruses, human adenoviruses, Cryptosporidium oocysts, Giardia cysts, Salmonella and Campylobacter. Sites were selected to represent five geographical areas covering New Zealand and five categories of predominant environmental impact: birds, dairy farming, forestry/undeveloped, municipal, and sheep/pastoral farming. Six of the sites were also source waters for treated drinking-water supplies. Of the indicators, E. coli was detected in 99 % of all samples, with somatic coliphage being detected most of the time (89 %). Of the pathogens tested, Campylobacter and human adenoviruses were inferred to be the most likely to cause human waterborne illness to recreational freshwater users. Using data from all sites, an estimated 5 % of notified campylobacteriosis cases in New Zealand could be attributable to water contact recreation. The critical value for E. coli as an indicator of increased Campylobacter infection is in the range of 200-500 E. coli per 100 ml. This result has been used to derive new national water quality guidelines for recreational fresh water in New Zealand.     

A meta‐analysis of case‐control studies examining sporadic campylobacteriosis in Australia and New Zealand from 1990 to 2016

Objective : We conducted a meta‐analysis of case‐control studies to identify locally relevant risk factors for sporadic campylobacteriosis in Australia and New Zealand. Methods : We searched Medline, Web of Science, ProQuest and Google Scholar using PRISMA guidelines. Reference lists and grey literature were hand‐searched. Meta‐analyses were conducted in the R package ‘metafor’ using published odds ratios and 95% confidence intervals. Results : We identified 325 articles, from which we included 10 that described case‐control studies. Four risk factors were statistically significant in the meta‐analysis: eating undercooked poultry (OR=4.28, 95%CI 3.09–5.93); eating poultry cooked outside the home (OR=2.13, 95%CI 1.66–2.72); having pet chickens (OR=3.29, 95%CI 2.12–5.10); and overseas travel (OR=5.55, 95%CI 3.20–9.63). Among children, having pet dogs showed elevated but not significant risk (OR=1.57, 95%CI 0.99–2.49). Conclusions : We identified consumption of chicken meat and contact with domestic chickens as important risk factors for campylobacteriosis in Australia and New Zealand. Implications for public health : While consumption of chicken meat is a well‐known risk factor for campylobacteriosis, zoonotic transmission is often overlooked. This research indicates a greater need for public health awareness surrounding zoonotic campylobacteriosis, especially for young children.     

Large-scale freshwater microbiological study: rationale, results and risks

A fifteen-month fortnightly survey of microbial health risk indicators and pathogens has been carried out at 25 freshwater recreational and water supply sites distributed throughout New Zealand, for: E. coli, Clostridium perfringens spores, F-RNA bacteriophage, somatic coliphage, human enteroviruses, human adenoviruses, Cryptosporidium oocysts, Giardia cysts, Salmonella and Campylobacter. Sites were selected to represent five geographical areas covering New Zealand and five categories of predominant environmental impact: birds, dairy farming, forestry/undeveloped, municipal, and sheep/pastoral farming. Six of the sites were also source waters for treated drinking-water supplies. Of the indicators, E. coli was detected in 99 % of all samples, with somatic coliphage being detected most of the time (89 %). Of the pathogens tested, Campylobacter and human adenoviruses were inferred to be the most likely to cause human waterborne illness to recreational freshwater users. Using data from all sites, an estimated 5 % of notified campylobacteriosis cases in New Zealand could be attributable to water contact recreation. The critical value for E. coli as an indicator of increased Campylobacter infection is in the range of 200–500 E. coli per 100 ml. This result has been used to derive new national water quality guidelines for recreational fresh water in New Zealand.     

Changing epidemiological trends of legionellosis in New Zealand, 1979-2009

This study evaluated the spatio-temporal variation of Legionella spp. in New Zealand using notification and laboratory surveillance data from 1979 to 2009 and analysed the epidemiological trends. To achieve this we focused on changing incidence rates and occurrence of different species over this time. We also examined whether demographic characteristics such as ethnicity may be related to incidence. The annual incidence rate for laboratory-proven cases was 2·5/100,000 and 1·4/100,000 for notified cases. Incidence was highest in the European population and showed large geographical variations between 21 District Health Boards. An important finding of this study is that the predominant Legionella species causing disease in New Zealand differs from that found in other developed countries, with about 30-50% of cases due to L. longbeachae and a similar percentage due to L. pneumophila for any given year. The environmental risk exposure was identified in 420 (52%) cases, of which 58% were attributed to contact with compost; travel was much less significant as a risk factor (6·5%). This suggests that legionellosis has a distinctive epidemiological pattern in New Zealand.     

Case-case analysis of enteric diseases with routine surveillance data: Potential use and example results

Background

Case-control studies and outbreak investigations are the major epidemiological tools for providing detailed information on enteric disease sources and risk factors, but these investigations can be constrained by cost and logistics.

Methods

We explored the advantages and disadvantages of comparing risk factors for enteric diseases using the case-case method. The main issues are illustrated with an analysis of routine notification data on enteric diseases for 2006 collected by New Zealand's national surveillance system.

Results

Our analyses of aggregated New Zealand surveillance data found that the associations (crude odds ratios) for risk factors of enteric disease were fairly consistent with findings from local case-control studies and outbreak investigations, adding support for the use of the case-case analytical approach. Despite various inherent limitations, such an approach has the potential to contribute to the monitoring of risk factor trends for enteric diseases. Nevertheless, using the case-case method for analysis of routine surveillance data may need to be accompanied by: (i) reduction of potential selection and information biases by improving the quality of the surveillance data; and (ii) reduction of confounding by conducting more sophisticated analyses based on individual-level data.

Conclusion

Case-case analyses of enteric diseases using routine surveillance data might be a useful low-cost means to study trends in enteric disease sources and inform control measures. If used, it should probably supplement rather than replace outbreak investigations and case-control studies. Furthermore, it could be enhanced by utilising high quality individual-level data provided by nationally-representative sentinel sites for enteric disease surveillance.     

Declining Guillain-Barré syndrome after campylobacteriosis control, New Zealand, 1988-2010

Infection with Campylobacter spp. commonly precedes Guillain-Barré syndrome (GBS). We therefore hypothesized that GBS incidence may have followed a marked rise and then decline in campylobacteriosis rates in New Zealand. We reviewed records for 1988-2010: hospitalization records for GBS case-patients and campylobacteriosis case-patients plus notifications of campylobacteriosis. We identified 2,056 first hospitalizations for GBS, an average rate of 2.32 hospitalizations/100,000 population/year. Annual rates of hospitalization for GBS were significantly correlated with rates of notifications of campylobacteriosis. For patients hospitalized for campylobacteriosis, risk of being hospitalized for GBS during the next month was greatly increased. Three years after successful interventions to lower Campylobacter spp. contamination of fresh poultry meat, notifications of campylobacteriosis had declined by 52% and hospitalizations for GBS by 13%. Therefore, regulatory measures to prevent foodborne campylobacteriosis probably have an additional health and economic benefit of preventing GBS.     

Estimating community incidence of Salmonella, Campylobacter, and Shiga toxin-producing Escherichia coli infections, Australia

To estimate multipliers linking surveillance of salmonellosis, campylobacteriosis, and Shiga toxin-producing Escherichia coli (STEC) infections to community incidence, we used data from a gastroenteritis survey and other sources. Multipliers for severe (bloody stool/long duration) and milder cases were estimated from the component probabilities of doctor visit, stool test, sensitivity of laboratory test, and reporting to surveillance system. Pathogens were classified by the same severity criteria and appropriate multipliers applied. Precision of estimates was quantified by using simulation techniques to construct 95% credible intervals (CrIs). The multiplier for salmonellosis was estimated at 7 (95% CrI 4-16), for campylobacteriosis at 10 (95% CrI 7-22), and for STEC at 8 (95% CrI 3-75). Australian annual community incidence rates per 100,000 population were estimated as 262 (95% CrI 150-624), 1,184 (95% CrI 756-2,670), and 23 (95% CrI 13-54), respectively. Estimation of multipliers allows assessment of the true effects of these diseases and better understanding of public health surveillance.     

The regionality of campylobacteriosis seasonality in New Zealand

New Zealand has one of the highest incidences of campylobacteriosis in the developed world, which leads a global trend of increasing notifications of Campylobacter infections over the last decade. Foodborne and waterborne transmission have been implicated as significant mechanisms in the complex ecology of the disease in New Zealand. We examined both regional and temporal variation in notification rates to gain some insight into the role of the New Zealand environments in modifying disease incidence. Firstly, there is a marked difference in the seasonality of campylobacteriosis between the North and South Islands of New Zealand. The Far North and much of the rural North Island were found to display relatively low summer incidence and small inter-seasonal variation. Secondly, there appears to be a dispersed grouping of North Island urban areas, including Auckland, Hamilton, Napier and their hinterlands as well as a few areas on the South Island that exhibit higher summer incidence and more seasonality than the first group. Thirdly, Christchurch, Dunedin, much of the South Island and the lower North Island cities of Wellington and Upper Hutt appear to experience the highest summer incidence and strongest inter-seasonal variation in New Zealand. These three broad groupings of campylobacteriosis seasonality, constructed using a principal components analysis, suggest that the importance of transmission routes may vary regionally in New Zealand. The observed variation in seasonal incidence indicates a complex ecology that is unlikely to be explained by a single dominant transmission route across these three groupings.     

Poultry culling and Campylobacteriosis reduction among humans, the Netherlands

In the Netherlands in 2003, an outbreak of avian influenza in poultry resulted in extensive culling, especially of layer hens. Concurrently, human campylobacteriosis cases decreased, particularly in the culling area. These observations raise the hypothesis that Campylobacter spp. dissemination from poultry farms or slaughterhouses might contribute to human campylobacteriosis.     

Occurrence of Campylobacter, Salmonella, Yersinia enterocolitica and Listeria monocytogenes in some retail food products in Novi Sad

The official reporting system in the Province of Vojvodina (PV) indicates that cases of human salmonellosis were partly covered by complete epidemiological investigation including laboratory analysis of the suspected food. Intestinal campylobacteriosis and yersiniosis and four cases of septicemias caused by Listeria monocytogenes were not fully epidemiologically investigated. Actual country legislation on food safety does not include provisions for a routine control of the above mentioned pathogens except for Salmonella. In the PV, there are no other sources of data that contribute to risk assessment of the above food-borne diseases. A pilot investigation, performed in Novi Sad, indicated that 8.17% out of the total number of 257 retail food samples (90 of fresh meat and 167 of ready-to-eat food) had been contaminated with one of the tested bacteria Campylobacter or Salmonella or Listeria monocytogenes. Yersinia enterocolitica was not detected in any of the tested samples. Fresh poultry meat and other fresh meats were the dominant sources of the detected pathogens compared to samples of ready-to-eat food (p < 0.05). Campylobacter was detected in 18.8% and 10.0% samples of fresh poultry and other fresh meat respectively, which was not statistically significant (p > 0.05). Salmonella was detected in 3.3% samples of fresh poultry meat. Listeria monocytogenes was detected in 5.0% samples of fresh poultry and in 3.3% samples of other fresh meat, the difference was not statistically significant (p > 0.05). One sample (0.6%) of ready to eat food was contaminated with Campylobacter and one (0.6%) with Salmonella.     

Trends in the incidence of salmonellosis and campylobacteriosis in the Czech Republic

Salmonellosis and campylobacteriosis are the most frequently reported acute enteric diseases of infectious origin in the Czech Republic. Epidemiological data on salmonellosis and campylobacteriosis have been reportable in this country since 1951 and 1984, respectively. In 2003, 53,486 cases of acute enteric infections were reported: 26,899 (52%) diagnosed as salmonellosis and 20,063 (almost 40%) diagnosed as campylobacteriosis. In 1989, the annual incidence of salmonellosis was three times as high as in the previous year, the upward trend continued until 1995 (528/100,000) and since 1998 the salmonellosis incidence rates have been declining. The incidence of campylobacteriosis showed a progressive increase since 1984 to peak in 2002 with a following slight decline in 2003. Morbidity from salmonellosis and campylobacteriosis is highest in the age group 0-4-year-olds. The most frequent causative agents are Salmonella Enteritidis (96%) and Campylobacter jejuni, respectively. Both infections are foodborne. Ready-to-eat meals, poultry, confectionery and eggs seem to be most frequently implicated in outbreaks of salmonellosis in public catering and families. Sporadic cases of campylobacteriosis are mostly associated with ingestion of poultry and chopped meat. The incidence rates of these two infections are positively correlated with the average daily temperatures.     

The situation and preventive measures against the spread of avian influenza on the territory of the country

The Russian Federation, as the whole world community, is anxious about the established situation associated with the prevalence of avian influenza and a threat of its pandemic. Today avian influenza is a complex, i.e. medical, veterinary, social, and economic, problem. Since December 2003, the world has notified an avian influenza panepizootic that has covered 54 countries to date. Despite emergency measures to prevent the prevalence of this infection, resulting in the elimination of more than 100 million poultries, the virus has fixed in the natural population of wild birds and gained the capacity to infect human beings, which serves as a guide for considering it a possible predictor of pandemic virus. According to the WHO classification, the Russian Federation is at Step II of an interpandemic period when cases of the disease are not notified among the population; however, the subtype circulating among the animals can cause the disease to sufficient probability. To prevent mass mortality of influenza virus-infected birds and human contagion in the inhabited localities wherein epizootic is seen, the Russian Federation has organized and implemented a package of antiepizootic, veterinary-sanitary, and sanitary-antiepidemic measures, including on-line exchange of information on the epizootic and epidemiological situation with veterinary surveillance bodies; farmstead rounds are made for the early detection of ill persons among human beings, for which an additional medical personnel has been picked out; daily medical monitoring of the population and the workers of poultry factories, wherein poultry death has been recorded, has been organized; the places of annihilation of utilized fallen and forcedly killed poultry are notified; supervision of the sanitary and veterinary state of the market where alive poultry and ornamental birds are sold has been tightened; measures to lay in a stock of chemotherapeutical and chemoprophylactic agents producing an antiinfluenza effect, as well as that of disinfectants have been taken; poultry and other birds are daily examined. Three inactivated emulsified veterinary vaccines against avian influenza have been currently designed. The calculated size of poultry to be vaccinated is 74.6 million. Double vaccination requires that 150 million doses of the agent be manufactured.     

Campylobacteriosis, Eastern Townships, Quebec

Independent risk factors for campylobacteriosis (eating raw, rare, or undercooked poultry; consuming raw milk or raw milk products; and eating chicken or turkey in a commercial establishment) account for <50% of cases in Quebec. Substantial regional and seasonal variations in campylobacteriosis were not correlated with campylobacter in chickens and suggested environmental sources of infection, such as drinking water.     

湖南省2005-2017年人感染禽流感流行病学特征分析

目的 对湖南省发现的所有人感染禽流感病例进行流行病学特征分析，为防控策略的制定和调整提供科学依据。方法 对疫情概况、病例三间分布和暴露史进行描述，并报道家庭聚集性病例。结果 湖南省已发现人感染H5N1病例6例，人感染H5N6病例4例，人感染H7N9病例99例，人感染H9N2病例6例。病例主要发生在11月至次年4月。H5N1病例分布在5个市州，H5N6病例分布在4个市州，H9N2病例分布在3个市州，H7N9病例分布在13个市州。4种亚型人感染禽流感在男性和女性中均有发生。H5N1、H5N6和H9N2病例年龄较小，H7N9病例以中老年为主。51.0%的病例为农民。95.5%的病例有禽类或禽类污染的环境暴露史。湖南省已发现H5N1、H5N6疑似家庭聚集性病例和H7N9确诊家庭聚集性疫情。结论 禽类和禽类环境是人感染禽流感病毒的主要来源，开展环境监测有利于疾病的预测预警。禽流感病毒存在有限非持续的人传人现象，密切监测病毒基因变化，对密切接触者实行医学观察，对于防止二代病例发生有重要意义。     

Pathogen survival trajectories: an eco-environmental approach to the modeling of human campylobacteriosis ecology

Campylobacteriosis, like many human diseases, has its own ecology in which the propagation of human infection and disease depends on pathogen survival and finding new hosts in order to replicate and sustain the pathogen population. The complexity of this process, a process common to other enteric pathogens, has hampered control efforts. Many unknowns remain, resulting in a poorly understood disease ecology. To provide structure to these unknowns and help direct further research and intervention, we propose an eco-environmental modeling approach for campylobacteriosis. This modeling approach follows the pathogen population as it moves through the environments that define the physical structure of its ecology. In this paper, we term the ecologic processes and environments through which these populations move "pathogen survival trajectories." Although such a modeling approach could have veterinary applications, our emphasis is on human campylobacteriosis and focuses on human exposures to Campylobacter through feces, food, and aquatic environments. The pathogen survival trajectories that lead to human exposure include ecologic filters that limit population size, e.g., cooking food to kill Campylobacter. Environmental factors that influence the size of the pathogen reservoirs include temperature, nutrient availability, and moisture availability during the period of time the pathogen population is moving through the environment between infected and susceptible hosts. We anticipate that the modeling approach proposed here will work symbiotically with traditional epidemiologic and microbiologic research to help guide and evaluate the acquisition of new knowledge about the ecology, eventual intervention, and control of campylobacteriosis.