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PubMedDate not supplied

The risk of avian influenza in birds in Australia.

Avian influenza viruses may cause mild or severe disease in birds. There have been five recorded outbreaks of highly pathogenic avian influenza in birds in Australia, all of which were caused by the H7 subtype. These were quickly controlled and similar coordinated responses are expected for possible future outbreaks of avian influenza. Migratory birds are not regarded as the source of these outbreaks, and the prevalence of avian influenza viruses in wild birds in Australia is very low. Avian influenza H5N1, which emerged in birds in China in 1996, has spread to bird flocks in Asia, Europe and Africa. The main carriers of avian influenza, ducks, do not migrate to Australia, and currently the risk of H5N1 occurring in Australian birds appears to be low. Nevertheless, surveillance and response plans for outbreaks of highly pathogenic avian influenza have recently been upgraded across Australia.

Animal Migration↗

PubMedDate not supplied

Strategies for rapid response to emerging foodborne microbial hazards.

The foodborne outbreak paradigm has shifted. In the past, an outbreak affected a small local population, had a high attack rate, and involved locally prepared food products with limited distribution. Now outbreaks involve larger populations and may be multistate and even international; in many the pathogenic organism has a low infective dose and sometimes is never isolated from the food product. Delay in identifying the causative agent can allow the outbreak to spread, increasing the number of cases. Emergency intervention should be aimed at controlling the outbreak, stopping exposure, and perhaps more importantly, preventing future outbreaks. Using epidemiologic data and investigative techniques may be the answer. Even with clear statistical associations to a contaminated food, one must ensure that the implicated organism could logically and biologically have been responsible for the outbreak.

Botulism↗

PubMed2004

Genesis of a highly pathogenic and potentially pandemic H5N1 influenza virus in eastern Asia.

A highly pathogenic avian influenza virus, H5N1, caused disease outbreaks in poultry in China and seven other east Asian countries between late 2003 and early 2004; the same virus was fatal to humans in Thailand and Vietnam. Here we demonstrate a series of genetic reassortment events traceable to the precursor of the H5N1 viruses that caused the initial human outbreak in Hong Kong in 1997 (refs 2-4) and subsequent avian outbreaks in 2001 and 2002 (refs 5, 6). These events gave rise to a dominant H5N1 genotype (Z) in chickens and ducks that was responsible for the regional outbreak in 2003-04. Our findings indicate that domestic ducks in southern China had a central role in the generation and maintenance of this virus, and that wild birds may have contributed to the increasingly wide spread of the virus in Asia. Our results suggest that H5N1 viruses with pandemic potential have become endemic in the region and are not easily eradicable. These developments pose a threat to public and veterinary health in the region and potentially the world, and suggest that long-term control measures are required.

Animals↗

PubMed2005

A homozygous nonsense mutation (428G-->A) in the human secretor (FUT2) gene provides resistance to symptomatic norovirus (GGII) infections.

Noroviruses (formerly Norwalk-like viruses) are a major cause of acute gastroenteritis worldwide and are associated with a significant number of nosocomial and food-borne outbreaks. In this study we show that the human secretor FUT2 gene, which codes for an alpha(1,2)-fucosyltransferase synthesizing the H-type 1 antigen in saliva and mucosa, is associated with susceptibility to norovirus infections. Allelic polymorphism characterization at nucleotide 428 for symptomatic (n = 53) and asymptomatic (n = 62) individuals associated with nosocomial and sporadic norovirus outbreaks revealed that homozygous nonsense mutation (428G-->A) in FUT2 segregated with complete resistance for the disease. Of all symptomatic individuals, 49% were homozygous (SeSe) and 51% heterozygous (Sese428) secretors, and none were secretor negative (se428se428), in contrast to 20% nonsecretors (se428se428) among Swedish blood donors (n = 104) (P < 0.0002) and 29% for asymptomatic individuals associated with nosocomial outbreaks (P < 0.00001). Furthermore, saliva from secretor-positive and symptomatic patients but not from secretor-negative and asymptomatic individuals bound the norovirus strain responsible for that particular outbreak. This is the first report showing that the FUT2 nonsecretor (se428se428) genotype is associated with resistance to nosocomial and sporadic outbreaks with norovirus.

Caliciviridae Infections↗

PubMed1999

Antigenic and genetic characterisation of Newcastle disease viruses isolated from outbreaks in domestic fowl and turkeys in Great Britain during 1997.

Antigenic and genetic analyses of viruses from the 11 outbreaks of Newcastle disease in Great Britain, 12 of the outbreaks in Northern Ireland and the single outbreak in the Republic of Ireland which occurred in 1997, indicated that they were all essentially similar. In addition, the viruses from the British Isles were very similar to viruses isolated from three outbreaks in pheasants in Denmark between August and November 1996, from a goosander in Finland in September 1996, from an outbreak in chickens in Norway in February 1997, and from an outbreak in chickens in Sweden in November 1997. Viruses from outbreaks in other countries during 1995 to 1997 could be distinguished antigenically and/or genetically from the 1996 to 1997 Scandinavian/British Isles isolates, as could viruses responsible for two separate outbreaks in caged birds in quarantine premises in Great Britain in March 1997. Minor nucleotide differences in the 413-base region of the fusion gene and the 187-base region of the haemagglutinin-neuraminidase gene sequenced in this study allowed the 1996 to 1997 Scandinavian/British Isles isolates to be divided into groups. These groups broadly corresponded to the clusters of disease outbreaks, but suggested that the discrete outbreak in Scotland was probably the result of virus spread from Northern Ireland. Overall, the antigenic and genetic analyses of these viruses were consistent with the theory that the virus was introduced into the British Isles by migratory birds moving from north-east Europe. However, it was not possible to rule out other sources, such as the movement of pheasants from Denmark.

Animals↗

PubMed1998

Failure of mass antibiotic prophylaxis to control a prolonged outbreak of meningococcal disease in an Israeli village.

In January 1994 mass antibiotic prophylaxis was undertaken in the contiguous villages of Deir el-Asad and B'ine in northern Israel (combined population of 11600) in response to a prolonged outbreak of serogroup B meningococcal infection with an overall annual rate of 37.4 cases of infection per 100000 residents. The average case fatality rate in the villages was 23% compared with 11% in Israel during the same period. Neisseria meningitidis group B was identified in 9 of 13 (69%) cases. Seven of these were subtype P1.7,16. The persistence of the outbreak with its accompanying public reaction prompted the establishment of an intervention programme that included antibiotic prophylaxis for the whole community with monitoring for pharyngeal carriage of meningococci in a stratified sample of the population. The objectives were to achieve a reduction of carriage of the outbreak strain and to reduce morbidity and mortality. A total of 1036 pharyngeal swabs were taken 1 day before and 6 weeks after treatment. Antibiotic prophylaxis was administered in one dose: children under 5-years-old received ceftriaxone i.m.; all others received oral ciprofloxacin. Overall, 96% of the population received treatment. The carriage rate was 8.3% prior to treatment (three serogroup B:14:P1.7,16), and 1.3% afterwards (one serogroup B:14:P1.7,16). The intervention failed to eradicate carriage of the putative outbreak strain, or to reduce the incidence and fatality rates in the villages. The outbreak finally terminated in late 1996. Public health professionals should bear this experience in mind when faced with prolonged, localized, nonexplosive outbreaks of meningococcal disease associated with low carriage rates of the outbreak strain.

Adolescent↗

PubMed2004

Archiving of food samples from restaurants and caterers--quantitative profiling of outbreaks of foodborne salmonellosis in Japan.

The Ministry of Health, Labor and Welfare (former MHW) of Japan issued a Directive in 1997 advising restaurants and caterers to freeze portions of both raw food and cooked dishes for at least 2 weeks. This system has been useful for determining vehicle foods at outbreaks. Enumeration of bacteria in samples of stored food provide data about pathogen concentrations in the implicated food. Data on Salmonella concentrations in vehicle foods associated with salmonellosis outbreaks were collected in Japan between 1989 and 1998. The 39 outbreaks that occurred during this period were categorized by the settings where the outbreaks took place, and epidemiological data from each outbreak were summarized. Characteristics of outbreak groups were analyzed and compared. The effect of new food-storage system on determination of bacterial concentration was evaluated. Freezing and nonfreezing conditions prior to microbial examination were compared in the dose-response relationship. Data from outbreaks in which implicated foods had been kept frozen suggested apparent correlation between the Salmonella dose ingested and the disease rate. Combined with results of epidemiological investigation, quantitative data from the ingested pathogen could provide complete dose-response data sets.

Adolescent↗

PubMed2026

A comprehensive overview of monkeypox virus disease.

BACKGROUND: Monkeypox (mpox), caused by monkeypox virus (MPXV), re-emerged as a major global public health concern in 2022, resulting in widespread transmission beyond traditionally endemic regions. As of March 2026, 181,164 confirmed cases and 492 deaths had been reported across 144 countries globally. The unprecedented geographic spread of the outbreak highlighted important knowledge gaps in disease surveillance, prevention, and control. Given the ongoing global circulation of MPXV and the risk of future outbreaks, this review provides a comprehensive synthesis of current evidence on MPXV and mpox. METHODS: The literature, surveillance data, and public health reports available up to March 2026 were systematically reviewed and synthesized. The review comprehensively assesses viral biology, genetic diversity, epidemiology, transmission dynamics, clinical manifestations, pathogenesis, laboratory diagnosis, infection during pregnancy, host immune responses, immune evasion mechanisms, therapeutic interventions, and prevention strategies. FINDINGS AND CONCLUSIONS: Globally, the decline in public immunity following the cessation of routine smallpox vaccination, together with ongoing viral evolution, may have contributed to the resurgence of mpox. Advances in genomic surveillance, diagnostics, and public health preparedness have strengthened outbreak response; however, important gaps remain in understanding long-term immunity and optimal treatment strategies. This review summarizes current evidence on MPXV and mpox and highlights priorities for future research and public health interventions.

Antiviral therapy↗

PubMed2001

Characterization of capsid genes, expressed in the baculovirus system, of three new genetically distinct strains of "Norwalk-like viruses".

"Norwalk-like viruses" (NLVs), members of a newly defined genus of the family Caliciviridae, are the most common agents of outbreaks of gastroenteritis in the United States. Two features of NLVs have hindered the development of simple methods for detection and determination of serotype: their genetic diversity and their inability to grow in cell culture. To assess the immune responses of patients involved in outbreaks of gastroenteritis resulting from infection with NLVs, we previously used recombinant-expressed capsid antigens representing four different genetic clusters, but this panel proved insufficient for detection of an immune response in many patients. To extend and further refine this panel, we expressed in baculovirus the capsid genes of three additional genetically distinct viruses, Burwash Landing virus (BLV), White River virus (WRV), and Florida virus. All three expressed proteins assembled into virus-like particles (VLPs) that contained a full-length 64-kDa protein, but both the BLV and WRV VLPs also contained a 58-kDa protein that resulted from deletion of 39 amino acids at the amino terminus. The purified VLPs were used to measure the immune responses in 403 patients involved in 37 outbreaks of acute gastroenteritis. A majority of patients demonstrated a fourfold rise in the titer of immunoglobulin G to the antigen homologous to the outbreak strain, but most seroconverted in response to other genetically distinct antigens as well, suggesting no clear pattern of type-specific immune response. Further study of the antigenicity of the NLVs by use of VLPs should allow us to design new detection systems with either broader reactivity or better specificity and to define the optimum panel of antigens required for routine screening of patient sera.

Amino Acid Sequence↗

PubMed1999

Safeguarding production agriculture and natural ecosystems against biological terrorism. A U.S. Department of Agriculture emergency response framework.

Foreign pest introductions and outbreaks represent threats to agricultural productivity and ecosystems, and, thus, to the health and national security of the United States. It is advisable to identify relevant techniques and bring all appropriate strategies to bear on the problem of controlling accidentally and intentionally introduced pest outbreaks. Recent political shifts indicate that the U.S. may be at increased risk for biological terrorism. The existing emergency-response strategies of the Animal and Plant Health Inspection Services (APHIS) will evolve to expand activities in coordination with other emergency management agencies. APHIS will evolve its information superstructure to include extensive application of simulation models for forecasting, meteorological databases and analysis, systems analysis, geographic information systems, satellite image analysis, remote sensing, and the training of specialized cadres within the emergency-response framework capable of managing the necessary information processing and analysis. Finally, the threat of key pests ranked according to perceived risk will be assessed with mathematical models and "what-if" scenarios analyzed to determine impact and mitigation practices. An infrastructure will be maintained that periodically surveys ports and inland regions for the presence of exotic pest threats and will identify trend abnormalities. This survey and monitoring effort will include cooperation from industry groups, federal and state organizations, and academic institutions.

Agriculture↗

PubMed2006

Shigella sonnei biotype G carrying class 2 integrons in southern Italy: a retrospective typing study by pulsed field gel electrophoresis.

BACKGROUND: Emergence and global dissemination of multiresistant strains of enteric pathogens is a very concerning problem from both epidemiological and Public Health points of view. Shigella sonnei is the serogroup of Shigella most frequently responsible for sporadic and epidemic enteritis in developed countries. The dissemination is associated most often to human to human transmission, but foodborne episodes have also been described. In recent years the circulation of multiresistant strains of S. sonnei biotype g carrying a class 2 integron has been reported in many countries worldwide. In southern Italy a strain with similar properties has been responsible for a large community outbreak occurred in 2003 in Palermo, Sicily. The objective of this study was to date the emergence of the biotype g strain carrying the class 2 integron in southern Italy and to evaluate the genetic heterogeneity of biotype g S. sonnei isolated throughout an extended interval of time. METHODS: A total of 31 clinical isolates of S. sonnei biotype g identified in southern Italy during the years 1971-2000 were studied. The strains were identified at the serogroup level, characterized by biochemical tests and submitted to antimicrobial susceptibility testing. Molecular typing was performed by pulsed field gel electrophoresis (PFGE) after digestion of DNA by XbaI. Carriage of class 2 integrons was investigated by polymerase chain reaction (PCR) with specific primers and confirmed by restriction endonuclease analysis of amplicons. RESULTS: The 15 isolates of S. sonnei biotype g identified in the decade 1971-1980 showed highly heterogeneous drug resistance profiles and pulsotypes. None of the isolates was simultaneous resistant to streptomycin and trimethoprim and none was class 2 integron positive. On the contrary, this resistance phenotype and class 2 integron carriage were very common among the 16 strains of biotype g identified in the following two decades. Moreover, all the more recent isolates, but one, showed closely related pulsotypes. CONCLUSION: Although our findings refer to a limited geographic area, they provide a snapshot of integron acquisition by an enteric pathogen responsible for several outbreaks in the years 2001-2003 in Italy. Molecular typing, indeed, suggests that the emergence of biotype g class 2 integron carrying S. sonnei in southern Italy should be backdated to at least the late 1980s. In the following decades, the circulation of biotype g appears to be sustained by multiresistant highly related strains. Similar trend are described in several countries, but the questions about mechanism of emergence and worldwide spread of this pathogen remain open.

Bacterial Typing Techniques↗

PubMed2000

Human behavioural factors implicated in outbreaks of human anthrax in the Tamale municipality of northern Ghana.

The knowledge, attitude, beliefs and practices of cattle owners, herdsmen, butchers and meat consumers about anthrax were used to provide a better understanding of the major factors responsible for the frequent outbreaks of human anthrax in the Tamale municipality of northern Ghana. A total of 96% of the respondents, made up of 50 cattle owners, 50 herdsmen, 25 butchers and 125 consumers, knew of anthrax and the clinical signs indicative of anthrax in cattle. However, very few knew the causative agent and many attributed the disease to the supernatural. Eight percent of the respondents believed that herbal preparations could protect against human anthrax, while 9% indicated that they would seek help from traditional practitioners or herbalists, if they suspected anthrax. A significant proportion of respondents were of the view that animals, which had died of unknown causes could be eaten because they served as a source of inexpensive meat for the community, especially if the meat was cooked with herbs which was commonly thought to prevent anthrax. These attitudes, taken together with the low income of the population studied, made the consumption of meat from animals, which had died of unknown causes, an attractive option. This increased the vulnerability to human anthrax in an area with frequent anthrax outbreaks in livestock. The results of this study suggest that a public education campaign involving both veterinary and local health personnel on the actual cause and prevention of anthrax could reduce outbreaks of anthrax in people.

Animals↗

PubMed2000

Biological terrorism: understanding the threat, preparation, and medical response.

The thought of an outbreak of disease caused by the intentional release of a pathogen or toxin in an American city was alien just 10 years ago. Many people believed that biological warfare was only in the military's imagination, perhaps to be faced by soldiers on a far-away battlefield, if at all. Political factors--and possibly biotechnology--have changed that. As we enter the new millennium, national, state, and local governments in the United States are preparing for what is now called "not if, but when" biological terrorism. In contrast to the acute onset and first-responder focus with a chemical attack, in a bioterrorist attack, the physician and the hospital will be at the center of the fray. Whether the attack is a hoax, a small food-borne outbreak, a lethal aerosol cloud moving silently through a city at night, or the introduction of contagious disease, the physician who understands threat agent characteristics and diagnostic and treatment options and who thinks like an epidemiologist will have the greatest success in limiting the impact of the attack. As individual health-care providers, we must add the exotic agents to our diagnostic differentials. Hospital administrators must consider augmenting diagnostic capabilities and surveillance programs and even making infrastructure modifications in preparation for the treatment of victims of bioterrorism. Above all, we must all educate ourselves. If done correctly, preparation for a biological attack will be as "dual use" as the facility that produced the weapon. A sound public health infrastructure, which includes all of us and our resources, will serve this nation well for the control of disease, no matter what the cause of the disease.

Biological Warfare↗

PubMed2002

Biological terrorism: understanding the threat, preparation, and medical response.

The thought of an outbreak of disease caused by the intentional release of a pathogen or toxin in an American city was alien just 10 years ago. Many people believed that biological warfare was only in the military's imagination, perhaps to be faced by soldiers on a far-away battlefield, if at all. The "anthrax letters" and the resulting deaths from inhalation anthrax have changed that perception. The national, state, and local governments in the United States are preparing for what is now called "not if, but when and how extensive" biological terrorism. In contrast to the acute onset and first-responder focus with a chemical attack, in a bioterrorist attack, the physician and the hospital will be at the center of the fray. Whether the attack is a hoax, a small food-borne outbreak, a lethal aerosol cloud moving silently through a city at night, or the introduction of contagious disease, the physician who understands threat agent characteristics and diagnostic and treatment options and who thinks like an epidemiologist will have the greatest success in limiting the impact of the attack. As individual health care providers, we must add the exotic agents to our diagnostic differentials. Hospital administrators must consider augmenting diagnostic capabilities and surveillance programs and even making infrastructure modifications in preparation for the treatment of victims of bioterrorism. Above all, we must all educate ourselves. If done correctly, preparation for a biological attack will be as "dual use" as the facility that produced the weapon. A sound public health infrastructure, which includes all of us and our resources, will serve this nation well for the control of the disease, no matter what the cause of the disease.

Biological Warfare↗

PubMed1995

When Science Isn't Enough: Wilhelm Hueper, Robert A. M. Case, and the Limits of Scientific Evidence in Preventing Occupational Bladder Cancer.

A recent outbreak of occupational bladder cancer in a Buffalo, New York, factory confirmed the carcinogenicity of ortho-toluidine, an aromatic amine that had first been implicated in human bladder cancer cases decades earlier. Events leading to this outbreak replicated the history of numerous earlier bladder cancer outbreaks among workers exposed to beta-naphthylamine and benzidine, two other aromatic amines that were widely used in the dye and rubber industries and that have been responsible for bladder cancer outbreaks in the United States, Germany, Switzerland, England, France, Italy, Austria, Czechoslovakia, the former Soviet Union, Poland, and China. The historic development of scientific knowledge of occupational bladder cancer prefigured many debates that later occurred around other environmental carcinogens; two of the giants of occupational medicine, Wilhelm Hueper and Robert A. M. Case, played seminal roles in the study of these chemicals. Examination of the history of worker exposure to aromatic amines and the subsequent development of bladder cancer at Du Pont, Allied Chemical, and other U.S. manufacturers demonstrates that these carcinogens were regulated only after cancer epidemics were recognized. Production and use of aromatic amines continues in developing countries; these nations will inevitably experience similar outbreaks unless steps are taken to eliminate exposure to these deadly chemicals. This paper chronicles the history of occupational bladder cancer in the United States, highlighting the roles of Hueper and Case in occupational cancer investigation and prevention.

Journal Article↗

PubMed2004

An outbreak of leptospirosis in Orissa, India: the importance of surveillance.

OBJECTIVE: To demonstrate the importance of surveillance systems in detecting emerging diseases and highlighting the strengths and weaknesses of an existing one. METHODS: The Orissa multi-disease surveillance system (OMDSS) was introduced in November 1999. Reporting units from the periphery send data to the district on a weekly basis. These reports are analysed regularly. A district task force (DTF) was available to intervene in the event of an outbreak. The OMDSS detected an increasing number of cases with fever and jaundice in June 2002. The DTF investigated this outbreak using clinical, epidemiological and laboratory tools to identify its cause. RESULTS: This outbreak, in a remote corner of India, was detected within 4 days by an existing surveillance system. Action was initiated within 24 h, but it took approximately two more weeks for the causative agent to be diagnosed. A total of 143 people were suspected to have leptospirosis between 23 June 2002 and 31 July 2002. The attack rate was 5.95% and the case fatality ratio (CFR) was 7.69%, both lower than outbreaks reported elsewhere in India. While males were infected more often than females, the CFR was higher among females and among the 6-15 year age groups. Exposure to infected water in a canal was the probable cause of the outbreak. IgM antibodies were positive in 33 of the patients and six patients tested positive for PCR and culture. Leptospirosis interrogans serovar canicola, Leptospirosis interrogans serovar pomona and Leptospirosis interrogans serovar hebdomadis were isolated. CONCLUSIONS: Leptospirosis is a new disease in this region of India. This outbreak was detected and diagnosed because of the surveillance system. The prompt response helped in containing the outbreak early enough. However, the morbidity and mortality could have been further mitigated if the delays in transmitting information had been minimized. An adequate laboratory support would have also helped considerably. We conclude stressing the importance of surveillance as a public health tool.

Adolescent↗

PubMed2004

Molecular epidemiology of Serratia marcescens in two hospitals in Gdańsk, Poland, over a 5-year period.

The history of the Serratia marcescens population in two hospitals in Danzig, Poland, over a 5-year period was analyzed in a study that combined MIC evaluation, typing by randomly amplified polymorphic DNA (RAPD) analysis and pulsed-field gel electrophoresis, and analysis of extended-spectrum beta-lactamases (ESBLs). We analyzed 354 isolates collected from 341 patients in two teaching hospitals in Danzig, Poland, from 1996 to 2000. The antimicrobial susceptibility profiles varied greatly, and for resistance to newer beta-lactams, probable AmpC cephalosporinase derepression and ESBL production occurred in about 23 and 19% of the isolates, respectively. RAPD typing, by which 69 types were discerned altogether, revealed a high degree of clonal diversity among the populations. However, the four most prevalent types were highly predominant, grouping approximately 71% of the isolates studied. These clones were observed in the two hospitals and were strong contributors to both outbreaks and the background of endemicity of the S. marcescens infections. Some of the strains that were not so widely spread (12 RAPD types; approximately 14% of the isolates) were responsible for several smaller outbreaks, and the remaining isolates represented unique RAPD types (53 types; approximately 15% of the isolates) and were probably sporadic introductions from other environments. ESBLs were identified in several different clones, and some of these had most likely already been introduced into the hospitals as ESBL producers, whereas the others acquired the ESBL-encoding genes from other enterobacterial strains in these environments. The CTX-M-3 enzyme, which is widely observed in Poland, was the most common ESBL type among the S. marcescens isolates, followed by TEM-47 and SHV-5. The complex epidemiology of ESBLs, especially in 1999 and 2000, must have arisen from the introduction of ESBL producers from other centers, their clonal dissemination, and the constant penetration of the S. marcescens populations with plasmids with ESBL genes. Multiple S. marcescens isolates were obtained from 11 patients, who probably represented both patients with recolonizations and reinfections and patients with recurrences of infections with the evolution of the strain's susceptibility.

Adolescent↗

PubMed2003

Bayesian methods for estimating pathogen prevalence within groups of animals from faecal-pat sampling.

Pathogens such as Escherichia coli O157:H7 and Campylobacter spp. have been implicated in outbreaks of food poisoning in the UK and elsewhere. Domestic animals and wildlife are important reservoirs for both of these agents, and cross-contamination from faeces is believed to be responsible for many human outbreaks. Appropriate parameterisation of quantitative microbial-risk models requires representative data at all levels of the food chain. Our focus in this paper is on the early stages of the food chain-specifically, sampling issues which arise at the farm level. We estimated animal-pathogen prevalence from faecal-pat samples using a Bayesian method which reflected the uncertainties inherent in the animal-level prevalence estimates. (Note that prevalence here refers to the percentage of animals shedding the bacteria of interest). The method offers more flexibility than traditional, classical approaches: it allows the incorporation of prior belief, and permits the computation of a variety of distributional and numerical summaries, analogues of which often are not available through a classical framework. The Bayesian technique is illustrated with a number of examples reflecting the effects of a diversity of assumptions about the underlying processes. The technique appears to be both robust and flexible, and is useful when defecation rates in infected and uninfected groups are unequal, where population size is uncertain, and also where the microbiological-test sensitivity is imperfect. We also investigated the determination of the sample size necessary for determining animal-level prevalence from pat samples to within a pre-specified degree of accuracy.

Agriculture↗