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INTRODUCTION: Mumps-containing vaccine was licensed in the 1990s in China with a single dose administered routinely to children aged 18-24 months since 2008. However, an increase in reported mumps cases during the period 2009 to 2012 casts doubt on the effectiveness of a single-dose mumps vaccination. In March 2012, large numbers of mumps cases in a day-care centre and primary school in Guangdong Province were investigated to estimate the effectiveness of mumps-containing vaccine. METHODS: A mumps case was defined as a case with acute onset of unilateral or bilateral swelling of the parotid gland or other salivary glands. Clinical data were collected among students and staff members in the two schools from 6 February to 3 June 2012. Vaccination history was obtained from immunization certificates. Vaccine effectiveness (VE) was calculated among children in classes that had more than two mumps cases. RESULTS: The cohort included 369 children from seven classes, four from the day-care centre and three from the primary school. Vaccination certificates available for 347 children showed immunization coverage of 82% (285/347). The overall attack rate was 14.6% (54/369); the VE for a single dose of mumps vaccine was 65% (95% confidence interval [CI]: 19%-85%) when given within three years and 15% (95% CI: -2%-52%) when given three to six years before the outbreak. For two doses of vaccine the VE was 53% (95% CI: -15-80%). DISCUSSION: A single dose of mumps-containing vaccine was not effective to prevent these outbreaks among preschool and schoolchildren. A second dose of mumps-containing vaccine to four to five-year-old children should be considered in China.

Background: On 12 May 2012, over 200 college students with acute diarrhoea were reported to the Guizhou Center for Disease Control and Prevention. We conducted an investigation to identify the agent and mode of transmission and to recommend control measures. Methods: A suspected case was a person at the college with onset of > two of the following symptoms: diarrhoea (more than three loose stools in 24 hours), abdominal pain, vomiting or fever (> 37.5°C) between 6 and 15 May 2012. A confirmed case also had a positive Aeromonas hydrophila culture from a stool sample. A retrospective-cohort study of 902 students compared attack rates (AR) by dining place, meals and food history. We reviewed the implicated premise, its processes and preparation of implicated food. Results: We identified 349 suspected cases (AR = 14%) and isolated Aeromonas hydrophila from three stools of 15 cases. Students who ate in cafeteria A were more likely to be ill compared to those eating in other places (relative risk [RR]: 3.1, 95% confidence interval [CI]: 2.0–4.8). The cohort study implicated cold cucumber (RR: 2.6, 95% CI: 2.0–3.3) and houttuynia dishes (RR: 1.8, 95% CI: 1.4–2.3). Environmental investigation showed that vegetables were washed in polluted water from a tank close to the sewage ditch, then left at 30°C for two hours before serving. The Escherichia coli count of the tank was well above the standard for drinking water. Conclusion: This outbreak of Aeromonas hydrophila was most probably caused by salad ingredients washed in contaminated tank water. We recommended enhancing training of foodhandlers, ensuring tanks and sewerage systems comply with appropriate standards and adequate monitoring of drinking water sources.

Background: In May 2012, an outbreak of viral hepatitis A was reported to the Guangxi Center for Disease Control and Prevention from a middle school in Liujiang County. An investigation was conducted to identify the cause and mode of transmission and to recommend control and prevention measures.Methods: A case was defined as any person from the middle school with onset of fatigue, anorexia, abdominal pain, diarrhoea or jaundice from 20 February to 20 May 2012. We compared attack rates (AR) between boys and girls, assuming that only boys used well water and girls used pipeline water. We then selected 133 students from three classes in each of the three grades to compare AR by reported water source and drinking history.Results: There were 22 cases, an AR of 3.8% (21/553) for students and 1.5% for teachers (1/65). Those who used well water were 8.7 (95% confidence interval [CI] = 2.1–37.2) times more likely to be ill than those using pipeline water. The cohort study showed that students who reported using well water daily were 5.2 (95% CI = 0.7–41.8) times more likely to be ill than those that reported using the pipeline water daily. Eighteen cases were confirmed as hepatitis A.Conclusion: This hepatitis A outbreak was potentially caused by a contaminated school well. We recommended that the school discontinue using the well and that the students should drink boiled water. As there is a vaccine for hepatitis A, we recommended that several doses of the vaccine be stored for controlling outbreaks and for immunizing susceptible populations in future outbreaks.

Introduction: Measles is an acute, highly communicable viral disease, with measles outbreaks usually occuring in settings where there are unvaccinated populations. After being notified of a cluster of five measles cases in a Singapore public hospital in August 2011, the Ministry of Health Singapore conducted an outbreak investigation.Methods: Active case detection was conducted, and all notified cases’ movement history within the hospital were reviewed to determine any common exposures in place and time. Cases were classified as nosocomial if they had contact with other measles cases in the hospital seven to 21 days before onset dates. Laboratory testing included serological and molecular diagnostic methods.Results: Of the 14 cases, seven cases were nosocomial cases. Investigations identified two wards where cases were epidemiologically linked. Two cases in Ward A were of D8 genotype and genotypically 100% identical, thus confirming a common source of infection. The six cases in Ward B (including one transferred from Ward A) had overlapping periods of admission and three cases were of the same D8 genotype, with a single nucleotide difference.Discussion: The epidemiological linkages of the cases and laboratory findings suggest nosocomial transmission in Wards A and B. As a result of this investigation, the hospital implemented a new policy of isolating suspected measles cases instead of waiting until they had been laboratory confirmed. This investigation emphasizes the importance of early identification and isolation of suspected measles cases within health care institutions and reinforces the requirement for high measles vaccination coverage of health care workers.

BACKGROUND: Seventeen cases of locally acquired measles occurred in South Western Sydney and Sydney local health districts between July and October 2011. Three of the cases were known to have at least one dose of measles-mumps-rubella (MMR) vaccine. Seven cases were infected within a health care setting waiting room by five index cases. Current national protocols require follow-up of all susceptible contacts in the same waiting room for any length of time for up to two hours after the index case has left. METHODS: Cases were interviewed using a standardized questionnaire. Information included: demographics, illness and activities during the exposure and infectious periods. Health care settings provided arrival and discharge times, maps of floor layouts and location of patients during stay. RESULTS: All health care setting transmission occurred in cases who were present at the same time as their index cases, with crossover time ranging from 20 to 254 minutes. No index case was isolated. Index cases were between day four and six of illness when transmission occurred. None of the five index cases and one of seven secondary cases had received at least one dose of MMR vaccine. Of the seven secondary cases, two were one year of age, one was 17 years old and four were between 30 and 39 years old. CONCLUSION: As Australia moves towards measles elimination, follow-up of cases is important; however, with limited public health resources a targeted response is vital. In this small but well documented series of secondary cases acquired in a health care setting, all were infected following direct, proximate contact of at least 20 minutes. Changes to the national guidelines may be warranted, ensuring that limited resources are focused on following up contacts at greatest risk of disease.

Background: Fifty-eight syphilis cases were notified from Darkhan-Uul Province in the first three months of 2012, which is double that of the same period in 2011. The objective of this investigation was to confirm the existence of the outbreak, examine the risk factors of cases and develop recommendations to prevent further spread.Methods: We conducted a descriptive study of cases notified to the national surveillance system diagnosed with syphilis between 1 January and 20 March 2012 in Darkhan-Uul Province. Additional data were collected from doctors’ record books and outpatient cards. We compared outbreak cases to non-outbreak cases notified in Darkhan-Uul Province in 2011.Results: The total notification rate was 62.3 per 100 000. The notification rate was highest among 20–29 year olds, and 38 (65.5%) were females. More males than females were detected through contact tracing (45% compared with 10.5%). Only 10% of cases reported using condoms during their last sexual encounter, with 65.5% reporting having had casual sex or multiple sex partners. There were no homosexual cases. Compared to the non-outbreak cases, outbreak cases had a significantly higher proportion of detection through contact tracing (22.4% compared with 0.7%) but a lower proportion of detection through prevention (3.5% compared with 26.5%). There was also a higher proportion of primary syphilis in outbreak cases (62.1% compared with 41.7%).Conclusion: The syphilis outbreak in Darkhan-Uul Province was confirmed. We recommended effective contact tracing followed by timely diagnosis and treatment. Health promotion activities targeted to high school, college and university students on syphilis infection and prevention as well as condom usage were recommended for future prevention.

Objective After notification of a suspected case of anthrax following the slaughtering of a sick cow in Banlu village, an area that has not had any anthrax cases for decades, we aimed to confirm the outbreak, determine the transmission mechanism and implement control measures. Methods The outbreak response team interviewed all people that had contact with the sick cow. Three types of cases' specimens were collected and tested by blood smear, real-time polymerase chain reaction (PCR) and the gold colloid method. Traceback of potentially contaminated meat and cattle were conducted. Results There were five confirmed and three probable cases verified among 17 people who had contact with the sick cow - an attack rate of 47%. The incubation period ranged from one to eight days with a median of two days. All eight cases had lesions. All were native residents of Banlu village aged between 21 and 48 years. Five male cases were professional butchers; two females and one male were temporary assistants. The sick cow's meat and hide, as well as all cattle processed at the same time, were recalled. Hypochlorite was used to disinfect the contaminated environments, butchering facilities and the contacts' personal effects. Conclusion This outbreak was caused by anthrax bacillus transmitted to contacts from the tissues of the sick cow. Control of the outbreak was managed by recalling all potentially infected meat and disinfecting the slaughter house and the suspected cases' personal effects and environment.

Background: On 23 May 2012, a university in Jiangxi, China reported a gastroenteritis outbreak. We investigated the outbreak to identify the agent, source and mode of transmission and to recommend control measures.Methods: A case was defined as any person from the university with onset of diarrhoea (≥3 times/24h) from 1 to 31 May 2012. Active case finding was conducted by reviewing university hospital and drug-store records and interviewing students, workers and teachers. We then conducted a case-control study in which we compared food, water and environmental exposure history. Water samples were collected and tested.Results: We identified 417 cases – an attack rate (AR) of 4.7% (417/8781) for the university. There were 416 student cases (AR = 5.7%) distributed across all 11 colleges, five of which were more heavily affected (AR range = 5.9%–14%). In the case-control study, cases had higher odds of having drunk bottled water (odds ratio [OR] = 4.1; 95% confidence interval [CI] = 1.7–9.9), and there was a dose–response relationship (X 2 trend = 4.6, P < 0.05). Drinking boiled bottled water was inversely associated with being a case (OR = "0.22," 95% CI = "0.07–0.71)." Eating in any of the three university canteens or drinking water from the city water supply was not associated with being a case. Pathogenic Escherichia coli was isolated from two unopened bottled water specimens and from four student cases.Conclusion: This gastroenteritis outbreak was most likely caused by contaminated bottled water. The company in question has been shut down and no further cases have been reported. Increased regulation of bottled water plants and better coordination between different investigators for future outbreaks is recommended.

Introduction: A large outbreak of pertussis was detected during March 2011 in Goilala, a remote district of the Central Province in Papua New Guinea, characterized by rugged topography with no road access from the provincial headquarters. This outbreak investigation highlights the difficulties in reporting and responding to outbreaks in these settings. Method: The suspected pertussis cases, reported by health workers from the Ononge health centre area, were investigated and confirmed for the presence of Bordetella pertussis DNA using the polymerase chain reaction (PCR) method. Results: There were 205 suspected pertussis cases, with a case-fatality rate (CFR) of 3%. All cases were unvaccinated. The Central Province conducted a response vaccination programme providing 65% of children less than five years of age with diphtheria–pertussis-tetanus-HepB-Hib vaccine at a cost of US$ 12.62 per child. Discussion: The incurred cost of vaccination in response to this outbreak was much higher than the US$ 3.80 per child for routine outreach patrol. To prevent further outbreaks of vaccine-preventable diseases in these areas, local health centres must ensure routine vaccination is strengthened through the “Reaching Every District” initiative of the National Department of Health.

Introduction: Foodborne outbreaks are common in Cambodia, but only a few investigations documenting the etiology and source have been conducted. In April, we learnt of 49 acute diarrhoea cases in a village following a wedding banquet. We undertook an investigation to identify the pathogen, source and mode of transmission.Methods: We interviewed banquet hosts and food handlers to obtain the menu and guest list. Guests were asked about signs and symptoms and onset of illness, time of meal and food or drinks consumed. Rectal swabs were taken from 13 cases for culture. A case-control study was undertaken; cases were guests who had acute diarrhoea within three days after the wedding and controls were guests who remained well during the same time period.Results: There were 256 guests. Of 69 interviewees, 52 got sick (attack rate 75%). Aside from diarrhoea, cases had abdominal pain (94%), vomiting (48%), nausea (42%) and fever (25%). Incubation periods ranged from seven to 51 hours (median 16.5). Rectal swabs from three cases grew Vibrio parahaemolyticus. Among the food and drinks served, vegetable salad with raw octopus was the only one associated with illness (odds ratio: 6.6, 95% confidence interval: 1.3–36.1, P = 0.01).Discussion: Vegetable salad with raw octopus was the suspected vehicle for transmission of this Vibrio parahaemolyticus enteritis outbreak. Messages regarding the risks from eating raw seafood were disseminated, and food handlers were advised to cook seafood to high temperatures. Efforts to improve foodborne disease surveillance and food safety are being undertaken.

Introduction: The Gurvantes district in Omnogovi Province reported a suspected mumps outbreak to the Mongolia Ministry of Health in March 2011. An outbreak investigation team was established to verify the diagnosis and to determine the magnitude of the outbreak.Methods: The descriptive study comprised retrospective investigation of local hospital medical records and surveillance data, and interviews with school teachers, doctors, probable cases and their close contacts. The World Health Organization standard case definition was used to define mumps cases. Clinical specimens were collected for laboratory confirmation.Results: There were 153 cases, none under two years of age, with the five- to 14-years-old age group having the highest rates. There was no difference by sex (P = 0.12). A single index case appeared to be the source of the outbreak, and there were four outbreak waves. Of the 129 cases with information on epidemiological links, 94 (72.3%) were linked to other cases at a kindergarten or school, 17 (13%) were from secondary spread of family members, two (1.5%) were from secondary spread of other relatives, and 16 had no established links. Eight cases (5.2%) were confirmed through laboratory investigation.Conclusion: This was the first high-magnitude mumps outbreak since the introduction of the measles-mumps-rubella vaccine in Mongolia in September 2009. There were no cases among vaccinated children; cases were seen among older children and adults not eligible for the vaccine. This suggests that immunity to mumps is still low in Mongolia. Future outbreaks may occur among this unvaccinated population.

Objective In July 2012, an outbreak of Campylobacter infection was investigated by the South Australian Communicable Disease Control Branch and Food Policy and Programs Branch. The initial notification identified illness at a surprise birthday party held at a restaurant on 14 July 2012. The objective of the investigation was to identify the potential source of infection and institute appropriate intervention strategies to prevent further illness. Methods A guest list was obtained and a retrospective cohort study undertaken. A combination of paper-based and telephone questionnaires were used to collect exposure and outcome information. An environmental investigation was conducted by Food Policy and Programs Branch at the implicated premises. Results All 57 guests completed the questionnaire (100% response rate), and 15 met the case definition. Analysis showed a significant association between illness and consumption of chicken liver pâte (relative risk: 16.7, 95% confidence interval: 2.4-118.6). No other food or beverage served at the party was associated with illness. Three guests submitted stool samples; all were positive for Campylobacter. The environmental investigation identified that the cooking process used in the preparation of chicken liver pâte may have been inconsistent, resulting in some portions not cooked adequately to inactivate potential Campylobacter contamination. Discussion Chicken liver products are a known source of Campylobacter infection; therefore, education of food handlers remains a high priority. To better identify outbreaks among the large number of Campylobacter notifications, routine typing of Campylobacter isolates is recommended.