High MERS-CoV seropositivity associated with camel herd profile, husbandry practices and household socio-demographic characteristics in Northern Kenya.

Despite high exposure to Middle East respiratory syndrome coronavirus (MERS-CoV), the predictors for seropositivity in the context of husbandry practices for camels in Eastern Africa are not well understood. We conducted a cross-sectional survey to describe the camel herd profile and determine the factors associated with MERS-CoV seropositivity in Northern Kenya. We enrolled 29 camel-owning households and administered questionnaires to collect herd and household data. Serum samples collected from 493 randomly selected camels were tested for anti-MERS-CoV antibodies using a microneutralisation assay, and regression analysis used to correlate herd and household characteristics with camel seropositivity. Households reared camels (median = 23 camels and IQR 16-56), and at least one other livestock species in two distinct herds; a home herd kept near homesteads, and a range/fora herd that resided far from the homestead. The overall MERS-CoV IgG seropositivity was 76.3%, with no statistically significant difference between home and fora herds. Significant predictors for seropositivity (P ⩽ 0.05) included camels 6-10 years old (aOR 2.3, 95% CI 1.0-5.2), herds with ⩾25 camels (aOR 2.0, 95% CI 1.2-3.4) and camels from Gabra community (aOR 2.3, 95% CI 1.2-4.2). These results suggest high levels of virus transmission among camels, with potential for human infection.

Interactive effects of age and respiratory virus on severe lower respiratory infection.

We investigated risk factors for severe acute lower respiratory infections (ALRI) among hospitalised children 8 months were at greater risk from influenza-associated ICU admissions and long hospital stay. Children with ADV had increased LOS across all ages. In the first 2 years of life, the effects of different viruses on ALRI severity varies with age. Our findings help to identify specific ages that would most benefit from virus-specific interventions such as vaccines and antivirals.

The East Jakarta Project: surveillance for highly pathogenic avian influenza A(H5N1) and seasonal influenza viruses in patients seeking care for respiratory disease, Jakarta, Indonesia, October 2011-September 2012.

Indonesia has reported the most human infections with highly pathogenic avian influenza (HPAI) A(H5N1) virus worldwide. We implemented enhanced surveillance in four outpatient clinics and six hospitals for HPAI H5N1 and seasonal influenza viruses in East Jakarta district to assess the public health impact of influenza in Indonesia. Epidemiological and clinical data were collected from outpatients with influenza-like illness (ILI) and hospitalized patients with severe acute respiratory infection (SARI); respiratory specimens were obtained for influenza testing by real-time reverse transcription-polymerase chain reaction. During October 2011-September 2012, 1131/3278 specimens from ILI cases (34·5%) and 276/1787 specimens from SARI cases (15·4%) tested positive for seasonal influenza viruses. The prevalence of influenza virus infections was highest during December-May and the proportion testing positive was 76% for ILI and 36% for SARI during their respective weeks of peak activity. No HPAI H5N1 virus infections were identified, including hundreds of ILI and SARI patients with recent poultry exposures, whereas seasonal influenza was an important contributor to acute respiratory disease in East Jakarta. Overall, 668 (47%) of influenza viruses were influenza B, 384 (27%) were A(H1N1)pdm09, and 359 (25%) were H3. While additional data over multiple years are needed, our findings suggest that seasonal influenza prevention efforts, including influenza vaccination, should target the months preceding the rainy season.

Influenza-associated excess mortality in southern Brazil, 1980-2008.

In order to estimate influenza-associated excess mortality in southern Brazil, we applied Serfling regression models to monthly mortality data from 1980 to 2008 for pneumonia/influenza- and respiratory/circulatory-coded deaths for all ages and for those aged ≥60 years. According to viral data, 73∙5% of influenza viruses were detected between April and August in southern Brazil. There was no clear influenza season for northern Brazil. In southern Brazil, influenza-associated excess mortality was 1∙4/100,000 for all ages and 9∙2/100,000 person-years for persons aged ≥60 years using underlying pneumonia/influenza-coded deaths and 10∙0/100,000 for all ages and 86∙6/100,000 person-years for persons aged ≥60 years using underlying respiratory/circulatory-coded deaths. Influenza-associated excess mortality rates for southern Brazil are similar to those published for other countries. Our data support the need for continued influenza surveillance to guide vaccination campaigns to age groups most affected by this virus in Brazil.

Pre-symptomatic transmission of pandemic influenza H1N1 2009: investigation of a family cluster, Brazil.

We investigated the first cluster of pandemic influenza H1N1 2009 reported in Brazil in May 2009. The index case-patient had travelled from the USA and had contact with 11 relatives before she presented with symptoms. We conducted face-to-face or telephone interviews with the index case-patient and all suspect cases. We found evidence of pre-symptomatic transmission of the virus to four of her contacts. This finding has public health implications because it indicates that viral transmission in communities may not be prevented solely by isolating symptomatic case-patients.

Epidemiological and genetic characteristics of norovirus outbreaks in long-term care facilities, 2003-2006.

To identify the epidemiological and genetic characteristics of norovirus (NoV) outbreaks and estimate the impact of NoV infections in an older population, we analysed epidemiological and laboratory data collected using standardized methods from long-term care facilities (LTCFs) during 2003-2006. Faecal specimens were tested for NoV by real-time reverse transcriptase-polymerase chain reaction. NoV strains were genotyped by sequencing. Of the 234 acute gastroenteritis (AGE) outbreaks reported, 163 (70%) were caused by NoV. The annual attack rate of outbreak-associated NoV infection in LTCF residents was 4%, with a case-hospitalization rate of 3·1% and a case-fatality rate of 0·5%. GII.4 strains accounted for 84% of NoV outbreaks. Median duration of illness was longer for GII.4 infections than non-GII.4 infections (33 vs. 24 h, P<0·001). Emerging GII.4 strains (Hunter/2004, Minerva/2006b, Terneuzen/2006a) gradually replaced the previously dominant strain (Farmington Hills/2002) during 2004-2006. NoV GII.4 strains are now associated with the majority of AGE outbreaks in LTCFs and prolonged illness in Oregon.

Rotavirus epidemiology: the Asian Rotavirus Surveillance Network.

Availability of new rotavirus vaccines has highlighted the need to collect local disease and economic burden data to aid decision makers at global, regional and country level. The World Health Organization and the GAVI Alliance recommended that generic protocols be used and that regional surveillance networks be established to collect these data, thereby helping to fast-track the introduction of these new vaccines into developing countries. Nine countries and regions participated in the first phase of the Asian Rotavirus Surveillance Network (ARSN), which collected data over a 2-year period during 2001-2003. Overall 45% of diarrhoea admissions in the region were positive for rotavirus, which was higher than had been anticipated. Significant rotavirus strain diversity was noted during the surveillance period. Data collection for a second phase of the ARSN commenced in 2004 and included a greater proportion of poorer countries that would in future be eligible for funding support for rotavirus immunization from GAVI. Limited economic evaluations in Asia have demonstrated the potential for new rotavirus vaccines to be cost-effective but more local analyses are required. Despite the ARSN's comprehensive data from a mix of developed and developing countries, Asia has lagged the Americas in terms of the introduction of rotavirus vaccines into National Immunization Programmes (NIPs). Lack on rotavirus vaccine efficacy data in Asia, particularly in poorer populations, will have contributed to this delay. Thus ensuring that all global regions are simultaneously involved in the evaluation of new vaccines from the beginning and also encouraging more regional collaborations of Ministry of Health representatives could help to accelerate the introduction of new vaccines into NIPs.

Bayesian estimation of hepatitis E virus seroprevalence for populations with different exposure levels to swine in The Netherlands.

Hepatitis E virus (HEV) is ubiquitous in pigs worldwide and may be zoonotic. Previous HEV seroprevalence estimates for groups of people working with swine were higher than for control groups. However, discordance among results of anti-HEV assays means that true seroprevalence estimates, i.e. seroprevalence due to previous exposure to HEV, depends on choice of seroassay. We tested blood samples from three subpopulations (49 swine veterinarians, 153 non-swine veterinarians and 644 randomly selected individuals from the general population) with one IgM and two IgG ELISAs, and subsets with IgG and/or IgM Western blots. A Bayesian stochastical model was used to combine results of all assays. The model accounted for imperfection of each assay by estimating sensitivity and specificity, and accounted for dependence between serological assays. As expected, discordance among assay results occurred. Applying the model yielded seroprevalence estimates of approximately 11% for swine veterinarians,approximately 6% for non-swine veterinarians and approximately 2% for the general population. By combining the results of five serological assays in a Bayesian stochastical model we confirmed that exposure to swine or their environment was associated with elevated HEV seroprevalence.

Large outbreak of norovirus: the baker who should have known better.

INTRODUCTION: In January 2001, 231 persons from the staff of a department in The Netherlands fell sick with diarrhoea and vomiting after a buffet lunch, which was prepared and served at a restaurant. Eighteen restaurant employees also reported illness. MATERIALS AND METHODS: To determine risk factors for illness a questionnaire was e-mailed to department staff and returned electronically. Employees from the restaurant and the bakery supplying the rolls were interviewed. Stool samples were collected from reported cases and from all the staff of the restaurant and the bakery supplying the rolls. Stools were tested for bacteria and noroviruses. RESULTS: Analyses of the questionnaires showed an increasing risk of illness with the number of rolls eaten (OR=2.0 95%CI=1.5-2.5). Investigations revealed the baker was suffering from gastroenteritis and had vomited in the bakery sink the day he prepared the rolls. However, he had cleaned up and washed his hands before continuing to work. Norovirus with an identical sequence was detected in the stool samples of ill persons from the department, and symptomatic employees from the restaurant and the bakery. CONCLUSION: Foodhandlers are unaware of the potential for transmission of norovirus. Use of electronically mailed questionnaires allowed rapid gathering and analysis of a large amount of data and subsequent identification of the source when detection of virus from the source (the baker) was still possible.

A European outbreak of Salmonella enterica serotype Typhimurium definitive phage type 204b in 2000.

OBJECTIVE: To describe the clinical, epidemiologic and microbiological features of a large outbreak of infection with a multiresistant Salmonella enterica serotype Typhimurium definitive type DT204b infection involving at least 392 people in five European countries. METHODS: Icelandic public-health doctors responded to a report on an Internet news site of an outbreak of infection with a multiresistant strain of Typhimurium DT104 in England by contacting the Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC). An international alert was sent out through Enter-net. All strains from England & Wales, The Netherlands, Scotland and Germany, and 17 of the outbreak isolates from Iceland, were phage-typed, screened for antimicrobial resistance, and subjected to molecular typing. Hypothesis-generating interviews were conducted, followed by case-control studies performed in Iceland and England. RESULTS: Isolates from cases in Iceland, England and Wales, The Netherlands, Scotland and Germany were identified as Typhimurium DT204b. The antimicrobial resistance pattern was ACGNeKSSuTTmNxCpL. All strains tested displayed an identical plasmid profile. Strains from five cases in England & Wales and five cases in Iceland possessed identical pulsed-field profiles. Although a common source was suspected, only Iceland implicated imported lettuce as a vehicle, with an analytic epidemiologic study (OR = 40.8; P = 0.005; 95% CI 2.7-3175). CONCLUSION: The identification of international outbreaks, necessary for investigation and control, can be facilitated by standardized phage-typing techniques, the electronic transfer of molecular typing patterns, formal and informal links established through international surveillance networks, and the early reporting of national outbreaks to such networks.

Surveillance of HCV infection in the Netherlands.

Two surveillance systems exist in the Netherlands to monitor hepatitis C (HCV) infections. Aggregated weekly laboratory data have been available since 1990. In 1999, HCV infection became a notifiable disease. Data showed the number of reported cases has remained stable. Male cases predominated (66%), mainly between age 15 to 54. Injecting drug use was the main route of transmission (64%). Despite its added value, the notifiable system should include more clinical data to better scrutinize future changes in transmission patterns.

Laboratory surveillance of bacterial gastroenteric pathogens in The Netherlands, 1991-2001.

Results of the Dutch laboratory surveillance of bacterial gastroenteritis between 1991 and 2001 are presented and compared with recent findings in general practices and in the community. Between 1996 and 2000 the mean annual number of stools screened by sentinel laboratories was about 1000 samples/100,000 inhabitants, which is 4% of the estimated annual incidence of gastroenteritis in the Dutch population. Campylobacter (36/100,000 inhabitants) and salmonella (24/100,000 inhabitants) were the main pathogens isolated. Since 1996, the incidence of laboratory confirmed salmonellosis decreased by 30%, predominantly among young children. The incidence of campylobacter was highest in urban areas and Salmonella Enteritidis emerged as the predominant serotype in urban areas. Between 1991 and 2001, multi-resistant Salmonella Typhimurium DT104 emerged to comprise up to 15% of all salmonella isolates in 2001. Reported rates of Shigella spp. and Yersinia spp. varied little, with average annual incidences of 3.2 and 1.2 cases/100,000 inhabitants, respectively. Escherichia coli O157 (90% STEC) was scarcely found (0.26/100,000).

Options for improvement of the Dutch measles vaccination schedule.

We investigated which vaccination schedule gives best protection to the vaccinating population, in case of a measles epidemic in pockets of unvaccinated individuals. We explored the effect of an additional measles vaccination (at 6 or 9 months), advancing the first measles-mumps-rubella (MMR) vaccination from 14 to 11 months, and advancing the second MMR from 9 to 4 years. Measures of protection among vaccinees (percentage of susceptibles, number of reported cases, percentage of lifetime spent susceptible) were estimated with a mathematical model of the impact of antibody level on seroconversion and immunity. Advancing the age of second MMR vaccination prevents considerably more cases among vaccinees than an extra early measles vaccination or advancing the age of first MMR vaccination.

Protecting the vaccinating population in the face of a measles epidemic: assessing the impact of adjusted vaccination schedules.

We investigated which vaccination schedule gives best protection to the vaccinating population, in case there is a measles epidemic in an area with low vaccine coverage. We considered combinations of an early measles vaccination (none, at 6 months or at 9 months), a measles-mumps-rubella (MMR) vaccination around the first birthday (at either 11 or 14 months), and MMR vaccination at an older age (at either 4 or 9 years). The different estimates on measures of protection (percentage of susceptibles, number of reported cases in an epidemic year, percentage of lifetime spent susceptible) relied on a mathematical model of decline of maternal antibody levels with age, and the impact of that antibody level on seroconversion and immunity. Model parameters were estimated from a Dutch population-based serological survey on measles antibodies. Different measures of protection favoured different vaccination schedules, but dropping the age of second MMR vaccination prevents considerably more cases than an extra early measles vaccination or dropping the age of first MMR vaccination.

Numerical simulation of a natural attenuation experiment with a petroleum hydrocarbon NAPL source.

A three-dimensional solute transport model with biological reactions is presented for simulating the natural attenuation study (NATS) at the Columbus Air Force Base in eastern Mississippi. NATS consisted of the release of a petroleum-based nonaqueous phase liquid (NAPL) and subsequent monitoring of BTEX (benzene, toluene, ethylbenzene, p-xylene), naphthalene, decane, and bromide in a shallow, unconfined aquifer. Conceptual and mathematical models were developed for NAPL source release, sequential aerobic/anaerobic biodegradation, and sorption during NATS. A multiple species, solute transport code (SEAM3D) was used to simulate fully three-dimensional transport and aerobic, nitrate-reducing, ferrogenic, and methanogenic hydrocarbon biodegradation. Simulation results matched individual BTEX concentration distributions collected five- and nine-months following NAPL release. SEAM3D mass-balance calculations at t = nine months indicated that 49% of the hydrocarbon mass that dissolved into the aqueous phase was consumed by biodegradation, 13% of this mass was sorbed, and the remaining 38% was present in the aqueous phase. Mass calculations at t = nine months further indicated that aerobic biodegradation accounted for the majority of hydrocarbon biodegradation (46% of the biodegraded mass), followed by ferrogenesis (28%), nitrate-reduction (21%), and methanogenesis (5%). Model results were particularly sensitive to the NAPL release rate, the initial ferric iron (Fe[III]) concentration, hydrocarbon utilization rates, initial condition for the anaerobic microbial populations, and dispersivity.

An epidemiological study of Taenia solium cysticercosis in a rural population in the Bolivian Chaco.

A survey of 100 rural households in a village in the Chaco region of Bolivia revealed a serious problem of Taenia solium cysticercosis, with a seroprevalence of 99/447 (22%) in humans and 102/273 (37%) in pigs. Risk factors for humans were being in older age groups, absence of sanitary facilities, poor formal education and inability to recognise infected pork. Significant risk indicators were a history of seizures and the reported elimination of worms in the faeces. Risk factors for pigs were being in older age groups and absence of sanitary facilities in the owner's house. The proportion of households with evidence of human cysticercosis was similar for those who owned pigs (48%) and those that did not (55%). This unexpected finding was attributed to the high overall prevalence of cysticercosis in pigs and the probability that everyone, regardless of pig-ownership, had ample opportunity to become infected in such communities. The main recommendation for reducing the prevalence of human cysticercosis was to provide more effective education campaigns, aimed at preventing both T. solium infection and cysticercosis.

Barrier-controlled monitored natural attenuation.

Three existing technologies (source containment, source reduction, and monitored natural attenuation) are integrated in barrier-controlled monitored natural attenuation (BCMNA)--a new approach for managing plumes of contaminated groundwater and remediating contaminated sites. The basic BCMNA concept uses a low-permeability, nonreactive barrier to release contaminants into an aquifer at a rate that optimizes natural attenuation. A simplified, one-dimensional model of the process is developed, and a hypothetical example of BCMNA is presented for a site contaminated with benzene. The analytical solution is used to demonstrate how contaminant concentrations can be controlled at a downgradient point of environmental compliance by manipulating design variables. BCMNA provides a greater degree of process control and risk reduction than monitored natural attenuation alone. BCMNA also holds promise for reducing remediation costs because (1) barriers can be constructed relatively inexpensively and (2) a cost-effective amount of source reduction can be applied inside the contained area with the BCMNA system remaining in place to safely complete the remediation process after source reduction is terminated. Further numerical modeling and a demonstration project are recommended to address important details and prove the concept.

In situ stimulation of groundwater denitrification with formate to remediate nitrate contamination.

In situ stimulation of denitrification has been proposed as a mechanism to remediate groundwater nitrate contamination. In this study, sodium formate was added to a sand and gravel aquifer on Cape Cod, MA, to test whether formate could serve as a potential electron donor for subsurface denitrification. During 16- and 10-day trials, groundwater from an anoxic nitrate-containing zone (0.5-1.5 mM) was continuously withdrawn, amended with formate and bromide, and pumped back into the aquifer. Concentrations of groundwater constituents were monitored in multilevel samplers after up to 15 m of transport by natural gradient flow. Nitrate and formate concentrations were decreased 80-100% and 60-70%, respectively, with time and subsequent travel distance, while nitrite concentrations inversely increased. The field experiment breakthrough curves were simulated with a two-dimensional site-specific model that included transport, denitrification, and microbial growth. Initial values for model parameters were obtained from laboratory incubations with aquifer core material and then refined to fit field breakthrough curves. The model and the lab results indicated that formate-enhanced nitrite reduction was nearly 4-fold slower than nitrate reduction, but in the lab, nitrite was completely consumed with sufficient exposure time. Results of this study suggest that a long-term injection of formate is necessary to test the remediation potential of this approach for nitrate contamination and that adaptation to nitrite accumulation will be a key determinative factor.

Risk of babesiosis and anaplasmosis in different ecological zones of Santa Cruz Department, Bolivia.

A cross-sectional study was done of seroprevalence of Babesia bigemina, B.bovis, and Anaplasma marginale in cattle from eastern Bolivia, to characterise the risk of tick-borne disease in three ecological zones. Nineteen farms were sampled in the subtropical humid zone, 13 in the dry subtropical zone and nine in the lower western valleys of the Andean massif. The enzyme-linked immunosorbent assay was used. All three pathogens were widespread. For B. bovis, seroprevalences were high (75-78%) in the two subtropical zones which thus had low risk of disease from this infection; but the western valleys were endemically unstable with higher risk. For B. bigemina, seroprevalences were lower (24-57%) in the two subtropical zones and thus these areas were endemically unstable for disease from this infection. However, the seroprevalence of B. bigemina in the western valleys was too low (13%) for risk of disease in susceptible cattle to be considered high. For A. marginale, the seroprevalences in the two subtropical zones were low (19-32%) and very low (6%) in the western valleys suggesting all these zones were endemically unstable for anaplasmosis. Data for individual farms were analysed for risk of both forms of babesiosis; this showed low risk of disease in the subtropical humid zone, higher risk in the dry subtropical zone and variable risk in the western valleys.