An outbreak of hepatitis A in recently vaccinated students from ice snacks made from contaminated well water.

On 30 May 2006, township S in Sichuan Province, China, reported an outbreak of hepatitis A (HA) in students who had recently received HA vaccine. The concern was raised that the vaccine had caused the outbreak. We attempted to identify the source of infection and mode of transmission. A HA case was defined as onset of jaundice or anorexia since 1 April 2006 with a twofold elevation of alanine aminotransferase (ALT) and anti-HA virus-IgM in a resident of or visitor to the township. Exposures to vaccine and snacks of 90 case-students to those of 107 control-students were compared. Thirty-four per cent of cases ate ice slush compared to 4.7% of controls (OR 4.1), and 51% of cases ate snow cones compared to 17% of controls (OR 8.3). The ice snacks were made with well water. HA virus RNA was detected by reverse transcription-polymerase chain reaction from patients' blood and well water. Untreated well water poses important dangers to the public in areas where piped, potable water is available.

Nosocomial malaria from contamination of a multidose heparin container with blood.

A girl developed Plasmodium falciparum malaria in Riyadh, Saudi Arabia, a non-malarious area. Twelve to 18 days before onset, she had been hospitalized for asthma on the same ward as three malaria patients. The only link between the malaria patients and the asthma patient was a multidose heparin container used to fill syringes for use on heparin locks and intravenous devices. Contamination of the heparin with blood occurred on at least one occasion when a needle had been left in place through the septum of this container and was used to refill a used syringe.

Seasonal, nontoxigenic Vibrio cholerae O1 Ogawa infections in the Eastern Region of Saudi Arabia.

BACKGROUND: Surveillance for Vibrio cholerae in the Eastern Region of Saudi Arabia has been ongoing since 1985 to detect and prevent local proliferation of imported cholera. In 1996 and 1997 the authors performed additional microbiologic and epidemiologic assessment of V. cholerae surveillance to better characterize a recurrent summertime pattern of V. cholerae infections in the Eastern Region of Saudi Arabia. METHODS: All health facilities routinely submitted stool or rectal swab specimens for isolation of V. cholerae from patients with gastroenteritis. In addition, specimens were taken from expatriate workers and household contacts of persons with confirmed V. cholerae infection. Forty-two isolates were evaluated for cholera enterotoxin by enzyme-linked immunosorbent assay, cholera toxin polymerase chain reaction, and Y1 adrenal cell assay; 12 isolates also were characterized by pulsed-field gel electrophoresis (PFGE). Interviews about potential exposures were done for all V. cholerae infections. RESULTS: Vibrio cholerae O1 serotype Ogawa biotype El Tor was identified in 113 gastroenteritis patients (6.0 per 100,000 population per year), 28 asymptomatic expatriate workers, and 16 of 982 household contacts of index patients. All symptomatic infected persons had mild illness that was not typical of cholera, and all 42 isolates evaluated were nontoxigenic. All 12 isolates evaluated by PFGE had an indistinguishable pattern (pattern 81). Infections appeared in late May, decreased in mid-July through August, increased again in September, and disappeared from December through April. Infections had a uniform geographic distribution and affected all ages. No linkage was identified between affected households, or between community cases and food-handlers or domestic servants. DISCUSSION: Surveillance in the Eastern Region of Saudi Arabia has identified a novel strain of nontoxigenic V. cholerae O1 Ogawa. This strain probably has a local environmental reservoir. Since cholera toxin is the primary virulence factor involved in the cause of cholera, assays for cholera toxin should be included in cholera surveillance.

Klebsiella pneumoniae bloodstream infections in neonates in a hospital in the Kingdom of Saudi Arabia.

OBJECTIVE: To identify risk factors for Klebsiella pneumoniae bloodstream infections (BSI) in neonates in a hospital in the Kingdom of Saudi Arabia (KSA). DESIGN: Two case-control studies among hospitalized neonates during February 15-May 14, 1991, and a procedural and microbiological investigation. SETTING: Hospital A, a maternity and children's hospital in KSA. PATIENTS: Case patients had a blood culture positive for K pneumoniae after >2 days of hospitalization and had no evidence of a nonblood primary site of infection. RESULTS: When the 20 case patients were compared with controls, hospitalization in a critical-care unit (odds ratio [OR], 5.5; 95% confidence interval [CI95], 1.20-51.1; P=.03) was identified as a risk factor. When the case patients were compared with a second set of controls matched by critical-care status, receipt of a particular intravenous fluid (D10%/0.2NS; OR, 11.0; CI95, 1.42-85.2; P=.009) or a blood product (OR undefined; P=.04) were identified as risk factors. Infusates were administered via umbilical catheters for most case and control patients (19/20 vs 15/20, P>.05); catheters were manipulated more frequently in patients in critical-care units. Umbilical catheter tip, skin, or mucus membrane K pneumoniae colonization occurred in 47% and 53% of evaluated case and control patients, respectively. Available K pneumoniae isolates from blood cultures and colonization sites had identical antimicrobial susceptibility patterns. Emphasis on handwashing, careful preparation and administration of infusates, and aseptic technique for catheter insertion, maintenance, and manipulation was temporally associated with resolution of the epidemic. CONCLUSIONS: This outbreak was probably due to infusion therapy practices that led to BSI in nursery patients colonized with K pneumoniae. Both catheter-related infections and extrinsic contamination of infusates may have occurred. Hospital personnel should be aware of their potential to spread nosocomial pathogens from person to person and should implement Centers for Disease Control and Prevention recommendations to decrease nosocomial BSIs.

Outbreak of poliomyelitis in Gizan, Saudi Arabia: cocirculation of wild type 1 polioviruses from three separate origins.

In 1989, a localized outbreak of 10 cases of poliomyelitis occurred in Saudi Arabia. Wild poliovirus type 1 was isolated from 5 patients. To determine the patterns of poliovirus circulation, partial nucleotide sequences of the poliovirus isolates were compared. These isolates were remarkably diverse. Two isolates were closely related to each other and to viruses isolated during the 1988 epidemic in Oman. Two other isolates were very similar to viruses found in Egypt. The fifth isolate was distantly related to the latter pair. The molecular data suggest that the 10 cases represented three separate outbreaks. The virologic findings underscore the potential for Saudi Arabia, which receives millions of guest workers and their families each year from countries in which polio is endemic, to be exposed to frequent importations of wild polioviruses. To restrict the circulation of imported polioviruses, Saudi Arabia must maintain high population immunity to poliovirus in all geopolitical divisions.

Plasmodium falciparum malaria transmitted in hospital through heparin locks.

BACKGROUND: After a community investigation had implicated hospital admission as a shared feature of a cluster of acute Plasmodium falciparum malaria (AFM) cases in Riyadh, Saudi Arabia, we began an in-hospital investigation to determine the method of transmission. METHODS: We investigated all AFM patients admitted to one paediatric hospital for any reason from December, 1991, to April, 1992. We classified AFM as locally acquired (LAFM) if during the month before AFM onset the patient had not visited a malarious area, and as hospital acquired (HAFM) if the LAFM patient had been admitted to hospital during that month. We compared exposures of HAFM cases with those of other patients sampled from the same wards. We observed nursing practices and investigated by anonymous questionnaire how nurses administered parenteral drugs. FINDINGS: Of 21 LAFM cases, 20 (95%) had a previous hospital admission (exposure admission) compared with 15 (25%) of 61 other patients (p < 0.001; chi 2 test). During the exposure admission, all HAFM patients had occupied the same room as, or a room adjacent to, an AFM patient; 14 (23%) of 60 other patients occupied the same room or rooms adjacent to an AFM patient (p < 0.001, chi 2). 90% of HAFM patients received infusions through a heparin lock during the exposure admission, compared with 49% of 120 general patients (p < 0.001, chi 2). 10% of nurses admitted to using one syringe for more than one heparin lock and 50% filled syringes with enough heparin for three to ten heparin locks. INTERPRETATION: P falciparum was transmitted between patients when single syringes were used on heparin locks of sequential patients. This practice would easily transmit other blood-borne agents.

An outbreak of salmonellosis among Filipinos in a private camp, Saudi Arabia

In October 1994, 19 Filipino professional staff of a large company in Damman city were hospitalized with acute febrile gastroenteritis. All ate three daily meals at the company cafeteria. A case-control investigation was begun to determine the cause of the outbreak. We searched the compound for any resident with a diarrhoeal illness. Both cases and controls were asked where and when foods were eaten during the three days before onset. Stool cultures were done for all patients and all 25 kitchen employees. Food cooking, handling and storage procedures were reviewed

Epidemiological investigation of an outbreak of meningococcal meningitis in Makkah (Mecca), Saudi Arabia, 1992.

During March and April of 1992, the health surveillance system began detecting increasing numbers of cases of meningococcal disease (MCD) in the Islamic holy city of Makkah (Mecca). We identified 102 bacteriologically confirmed cases (CC) and 80 suspected cases (SC) of MCD. Neisseria meningitidis was identified as Group A, III-1 clone. The ratio of male:female cases was 2.9:1. All age groups of males were affected. There was only one case among women aged 10-30; 50% of the adult female cases were 55 or older. The case-fatality ratio (CFR) was 14.7% among CC. Pakistanis, who comprised about one-third of the CC, had a CFR of 26.7%. Fifty-nine percent of CC were religious visitors. CC in residents were most common in persons living near the Holy Mosque (Haram), where the carriage rate reached 86%. A mass vaccination program against MCD was instituted, using AC bivalent meningococcal vaccine (MCV). An abrupt drop, from a mean of 15 CC per week to 2 CC per week (only in visitors), coincided with vaccinating 600,000 persons over 2 weeks. Makkah residents who had been vaccinated against MCD were less likely to have contracted MCD (OR = 0.17, 95% CI: 0.06-0.50). MCV was of no significant protective value if it had been administered 5 years before the outbreak. The main reason for not being vaccinated as stated by both cases (71%) and controls (45%) was not knowing about the disease. The age and sex differences probably relate to differences in exposures to crowded conditions. Health education should illuminate the seriousness of the disease and the importance of vaccination.

Meningococcal meningitis group A: a successful control of an outbreak by mass vaccination.

Jeddah is the main point of entry to the holy places in Saudi Arabia. An outbreak of meningococcal disease (MCD) occurred during the fasting lunar month for Muslims, Ramadan (March-April) of 1992. To assess the threat of local spread of MCD within Jeddah, the effects of previous and a mass vaccination programme against MCD during the outbreak, we reviewed the medical records of confirmed cases (CC) of MCD (defined as a bacteriologically confirmed case or a case diagnosed by latex test) and their vaccination status in the last five years before the outbreak. There were 41 CC of meningitis due to Neisseria meningitidis (group A). The ratio of males to females was 4.1:1. Thirty two percent of the cases were religious visitors. About one fourth (22%) of the cases were Pakistani. More than half (57%) of the cases, who were residents of Jeddah, lived in the north-eastern part of the city, as did half of the Pakistani cases. The case-fatality rate among CC was 19.5%. Persons who visited the Makkah (Mecca) during Ramadan were more likely to get the disease than those who did not (odds ratio [OR] = 6.1; 95% confidence interval [CI] 1.4-40.7). Unvaccinated persons were more likely to get the disease than those who were vaccinated against MCD (OR = 13.9; 95% CI 1.8-296). Meningococcal vaccine (MCV) against MCD was effective in preventing the disease. However, MCV was of no protective value if it had been administered more than five years before the outbreak. The reason mentioned most frequently for not being vaccinated by both cases (84%) and controls (57%) was lack of knowledge about the disease. Health education programmes should be strengthened and promoted. A good collaborative surveillance system between Jeddah and other holy cities, especially Makkah, is needed to abort outbreaks among religious visitors and to prevent the spread of MCD outbreaks.

Typhoid fever from water desalinized using reverse osmosis.

In May 1992, 81 bacteriologically confirmed cases of typhoid fever (TF) were identified in all districts of Tabuk City in northwestern Saudi Arabia. Attack rates (AR) in residential districts ranged from 0.9-10.3 per 10,000. Confirmed cases included 9 workers in the city's referral hospital, King Khalid Hospital (AR 140/10,000), 2 in families of medical staff, 57 in the community (AR 4.4/10,000) and 13 in a local military cantonment (AR 0.8/10,000). The outbreak began with the onset of TF in the three areas within 5 days, continued for 7 weeks, and ended 2 weeks after chlorination began. Among water sources, the odds ratio (OR) was highest (2.6; 95% confidence interval [CI] 1.25-5.39) for water purchased from reverse osmosis (RO) plants, especially RO plants supplied by one well (ASUW) (OR = 7.05; 95% CI 2.51-20.7). The aquifer for ASUW lay partially beneath a depression where city sewage collected. Unchlorinated water samples from ASUW 1 month after the outbreak ended yielded coliforms. ASUW probably became contaminated with Salmonella typhi when KKH demand overtaxed the aquifer and drew in surface water. Membranes in RO plants using this unchlorinated well water could then become fouled with S. typhi. RO plants, which are common throughout Saudi Arabia, need close monitoring. Water for RO must be prechlorinated to prevent microbiologic fouling of the membranes.

Guinea worm disease in Northern Uganda: a major public health problem controllable through an effective water programme.

A modified cluster survey was conducted in northwestern Uganda in 1984 to provide descriptive epidemiological data on dracunculiasis in a water programme target area. A total of 2014 people participated from 58 randomly selected clusters. Interviewers elicited information on age and sex of household members, number, date of emergence and location of Guinea worms, and type of and distance from water source in an endemic area. The survey yielded an incidence rate of 193 cases/1000 people per year, and a prevalence rate of 43 active cases/1000. Respondents who reported using ponds, reservoirs, valley tanks or rivers as their primary water source had the highest attack rates; those using boreholes, the lowest. Adolescents and adults differed little in risk, but the disease was less common among young children. Guinea worm disease displayed a bimodal seasonal pattern. We concluded that the survey method used for determining dracunculiasis incidence was appropriate in this setting. The incidence of this disease may be significantly reduced in Uganda through the country's commitment to the International Drinking Water Supply and Sanitation Decade.

Comparative efficacy of ceftriaxone and rifampicin in eradicating pharyngeal carriage of group A Neisseria meningitidis.

During an outbreak of meningococcal meningitis in Saudi Arabia, oral rifampicin (four doses in two days) was compared with a single intramuscular dose of ceftriaxone for prophylaxis in family contacts of patients with meningococcal disease. Pharyngeal samples were taken for culture before and 1 and 2 weeks after administration. Both follow-up cultures indicated that ceftriaxone was significantly more effective. At 1 week the eradication rates for ceftriaxone and rifampicin were 97% and 75%; at 2 weeks they were 97% and 81%, respectively. No serious side-effects were associated with either agent. Ceftriaxone may provide an effective alternative to rifampicin for prophylaxis in meningococcal contacts.

Acute schistosomiasis among Americans rafting the Omo River, Ethiopia.

An outbreak of acute schistosomiasis occurred among a group of adventurers who took part in a rafting expedition on the Omo River in Ethiopia in November 1981. Six (55%) of the 11 members of the expedition experienced Schistosoma mansoni infection confirmed by stool examination. Five of these six had symptoms compatible with acute schistosomiasis. Eosinophilia was the most frequent sign of infection (five of six), and fever, the most common symptom (four of six). Despite medical evaluations, illnesses had remained undiagnosed until January 1982. This outbreak should alert physicians to the risk of schistosomiasis among travelers to this part of Africa and the difficulty of correct diagnosis early in the course of the disease.

Epidemic salmonellosis from cheddar cheese: surveillance and prevention.

On August 3, 1976, ongoing Salmonella surveillance in Colorado first detected an epidemic of Salmonella heidelberg infections that eventually totaled 339 isolates. The majority of the cases occurred between July 23 and August 12 in two widely separated cities: Denver and Pueblo. Epidemiologic investigation successively incriminated 1) recent dining at Mexican-style restaurants (p less than 0.001), 2) eating foods containing cheese in these restaurants (p = 0.029), and 3) consumption of cheddar cheese from a single shipment of a single manufacturer (p less than 0.01). The prompt investigation enabled an embargo of 2087 kg (41%) of the contaminated cheese. S. heidelberg was isolated from seven production lots of the incriminated cheese. Surveillance and the epidemiologic investigation may have resulted in prevention of 25,000 diarrheal illnesses.