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Biomedical subjects

M S Ho

Publications and source records attributed to M S Ho.

At least 73 records · Page 4Linked to original sources

Estimates of morbidity and mortality rates for diarrheal diseases in American children.

Although the importance of diarrhea as a prime cause of morbidity and death in developing countries is well recognized, the disease burden in the United States has never been thoroughly examined. We have prepared national estimates of the annual number of cases of diarrhea in children less than 5 years of age and of the outcome, measured in terms of visits to a physician, hospitalizations, and deaths. The annual number of diarrheal episodes was estimated by reviewing longitudinal studies of childhood diarrhea conducted in the United States and extrapolating these data to the nation. Estimates of physician visits, hospitalizations, and deaths were prepared from a variety of national data sources. We estimate that 16.5 million children less than 5 years of age have between 21 and 37 million episodes of diarrhea annually. Of these, 2.1 to 3.7 million episodes lead to a physician visit, a total of 220,000 patients are hospitalized, and 325 to 425 children die. The major cost of diarrhea lies in the high numbers and cost of hospitalizations, because approximately 10.6% of hospitalizations in this age group are for diarrhea. Diarrheal deaths occur in relatively small numbers, are more common in the South and among black persons, are potentially avoidable, and could represent as much as 10% of the preventable postneonatal infant death in the United States. These estimates underscore the extensive burden of diarrheal illness in children in the United States and suggest that interventions to prevent disease or decrease its severity could be cost-effective.

Child, Preschool↗

Serotypes and electropherotypes of human rotavirus in the USA: 1987-1989.

The epidemiology of rotavirus gastroenteritis was investigated for two consecutive seasons (1987-1988 and 1988-1989) in seven locales in the continental USA. The 281 representative fecal samples obtained from children with diarrhea were electropherotyped and serotyped by an enzyme immunoassay with serotype-specific monoclonal antibodies and a new amplification typing technique (polymerase chain reaction typing). Serotype 1 was predominant in both years, particularly in the North and East; serotype 3 was second in frequency and found most often in the South; serotype 2 was detected only occasionally; serotypes 4, 8, and 9 were never found. Rotavirus strains were grouped into five major electropherotypes, each corresponded to a single serotype, and the relative migration of the gene segments 7-9 could be used to distinguish serotype 1 from serotype 3. The amplification typing technique proved to be of great value in typing the 17% of rotavirus-positive specimens untypable by the serologic technique.

Antibodies, Monoclonal↗

Foodborne Snow Mountain agent gastroenteritis with secondary person-to-person spread in a retirement community.

A variety of small round-structured viruses are being recognized with increasing frequency as a cause of gastroenteritis in the community, but have rarely been reported to cause outbreaks in hospitals or extended-care facilities. From March 20 through April 15, 1988, an outbreak of gastroenteritis occurred in a retirement facility in the San Francisco Bay area. Illness was characterized by diarrhea, nausea, and vomiting; two residents died. Attack rates were 46% (155 of 336) in residents and 37% (28 of 75) in employees. During the initial outbreak period, illness among residents was associated with two shrimp meals served in the facility dining hall (odds ratio = 6.7). Person-to-person transmission probably occurred: The risk of becoming ill one or two days after a roommate became ill was significantly greater than that of becoming ill at other times during the outbreak (risk ratio = 6.5). Microbiologic examinations for bacterial and parasitic enteric pathogens were negative; however, 27-nm viral particles were detected by immune electron microscopy and by blocking enzyme immunoassay to Snow Mountain agent in stools obtained at the onset of illness from one of six ill residents. Seroconversion (greater than fourfold antibody rise) to Snow Mountain agent was detected in acute- and convalescent-phase serum specimens from five of six ill residents as measured by enzyme immunoassay, but not for Norwalk agent as measured by radioimmunoassay. This report of an outbreak of Snow Mountain agent gastroenteritis in an extended-care facility documents that these difficult-to-identify 27-nm viruses can cause outbreaks in inpatient settings.

Aged↗

Gastroduodenal mucosa in uraemia: endoscopic and histological correlation and prevalence of helicobacter-like organisms.

This study aimed to determine the prevalence of endoscopic and histological gastroduodenitis as well as helicobacter-like organisms in patients with end stage renal failure undergoing maintenance dialysis treatment. A total of 322 out of 422 patients in our dialysis programme underwent endoscopy and gastroduodenal biopsy specimens were taken from 260. Endoscopic gastroduodenitis occurred in 158 (49%). Histological gastritis occurred in the gastric body or antrum in 134 patients (52%) and duodenitis in 52 (21%). There was no correlation between endoscopic and histological gastritis in contrast to a significant correlation for duodenitis. Helicobacter-like organisms occurred in the body or antrum in 81 (31%). Their presence was associated with gastritis--in particular acute and acute on chronic gastritis rather than chronic gastritis. Patients with gastritis were significantly older than those without (p less than 0.001) and had lower basal and peak acid outputs.

Acute Disease↗

Global seasonality of rotavirus infections.

Data from 34 studies of the etiology of childhood diarrhoea were compiled in order to investigate the seasonal patterns of rotavirus gastroenteritis and consider their implications for transmission of the virus. Rotavirus was detected in 11-71% of children with diarrhoea, and the median rate of detection (33%) was independent of the level of economic development or geographical region of the study area, as well as of the method of detection used. While rotavirus infections have been called a winter disease in the temperate zones, we found that their incidence peaked in winter primarily in the Americas and that peaks in the autumn or spring are common in other parts of the world. In the tropics, the seasonality of such infections is less distinct and within 10 degrees latitude (north or south) of the equator, eight of the ten locations exhibited no seasonal trend. Throughout most of the world, rotavirus is present all the year round, which suggests that low-level transmission could maintain the chain of infection. The virus is spread by the faecal-oral route but airborne or droplet transmission has also been postulated. The epidemiology of rotavirus--its seasonality in the cooler months, its universal spread in temperate and tropical zones in developed and less developed settings--more closely resembles that of childhood viruses that are spread by the respiratory route (such as measles) than that of common enteric pathogens that are spread predominantly by the faecal-oral route.

Americas↗

Viral gastroenteritis aboard a cruise ship.

A 32-nm small round structured virus (SRSV), possibly related to the Snow Mountain agent (SMA), was implicated as the cause of recurrent outbreaks of gastroenteritis on a cruise ship. There was no identifiable relation to food or water consumption, but the risk of gastroenteritis among passengers who had shared toilet facilities was twice that of those who had a private bathroom and the rate of illness was related to the number of passengers sharing a communal restroom (ie, with one or more toilets): contaminated bathrooms may be an important vehicle for person-to-person spread of this enteric agent. In each cabin, index patients who had vomited in their cabins were more likely to have had cabinmates who subsequently became ill than were index patients who had not vomited. These epidemiological findings implicate vomitus in the transmission of viral gastroenteritis and they are consistent with the transmission of viral agents by airborne droplets or person-to-person contact. New strategies for prevention of viral gastroenteritis should include protection against environmental contamination by viruses in airborne droplets or vomitus.

Acute Disease↗

Investigation of an outbreak of adult diarrhea rotavirus in China.

In 1987 an epidemic of diarrhea associated with adult diarrhea rotavirus (ADRV) occurred in Qinhuangdao City, China, affecting more than 200 persons and causing 2 deaths. The outbreak was introduced by a person returning from an epidemic area and was spread initially to his family members and subsequently to the entire community. Adults were at greater risk of diarrhea than children 0-4 y of age and, the duration of illness increased significantly with increasing age. ADRV was identified by ELISA and electron microscopy. The electropherotypes of all positive specimens were identical, consistent with the single point-source introduction of the virus. Seroconversion was detected in 6 of 7 ill persons with a blocking ELISA. Both asymptomatic infection and person-to-person spread identified in this epidemic suggest that current emphasis on preventing waterborne transmission may not control the introduction of ADRV into new areas. The predisposition of adults for more severe disease with ADRV is similar to the pattern observed with other enteric viruses such as the Norwalk agent and hepatitis A.

Adolescent↗

Simultaneous administration of rhesus rotavirus vaccine and oral poliovirus vaccine: immunogenicity and reactogenicity.

Rotavirus vaccine could be administered most efficiently if it were incorporated into routine childhood immunizations and did not interfere with the immune response to the other vaccines, principally oral poliovirus vaccine (OPV). We conducted a placebo-controlled randomized trial giving oral rhesus rotavirus vaccine (RRV) (strain MMU 18006) alone and together with a child's first dose of OPV and diphtheria-tetanus toxoids-pertussis to examine the possible interaction of these vaccines. A total of 102 infants 2 to 3 months of age were randomized into 3 groups to receive (1) RRV with OPV, (2) placebo with OPV and (3) RRV 2 weeks after OPV. All infants were given diphtheria-tetanus toxoids-pertussis. Serum samples were collected at the time of OPV immunization and 3 to 5 weeks later. Three to 5 weeks after OPV immunization 60% of infants had a 4-fold rise in neutralization titer to at least one of the three poliovirus serotypes. The rate of antibody response to poliovirus did not differ by RRV groups but a lower rate was correlated with a shorter interval (3 vs. 5 weeks) between OPV vaccination and antibody measurement. Fifty-six percent of infants had a 4-fold rise of IgA and 62% had a 4-fold rise of neutralizing antibody to RRV; this rise did not differ according to time of OPV immunization. RRV was not associated with side effects and may be safely given with OPV to infants 2 to 3 months of age.

Antibodies, Viral↗

Seroepidemiology of adult diarrhea rotavirus in China, 1977 to 1987.

In 1982, large outbreaks of diarrhea that were caused by group B adult diarrhea rotavirus (ADRV) occurred throughout the People's Republic of China. Until 1982, group B rotavirus had never been associated with disease in humans. To determine whether ADRV was a new virus introduced in 1982 or had been present before that time, we examined antibody titers of ADRV in gamma globulin (pooled immunoglobulin) pools that were prepared during 1977 to 1987 in four cities in the People's Republic of China (Shanghai, Lanzhou, Wuhan, and Chandu). ADRV antibodies were assayed by using a blocking enzyme-linked immunosorbent assay. Antibodies were present in most Chinese gamma globulins tested, including those collected in Shanghai before the 1982 epidemic, and absent from American reference pools. The highest titers of antibody to ADRV (3,200) were found in gamma globulins collected in 1983 in Shanghai just after the epidemic, and these were fourfold higher than titers present in the preceding years. The quality of the gamma globulins stored for up to 12 years was tested by measuring levels of immunoglobulin G to group A rotavirus; these were equally high in gamma globulin pools prepared in the United States and in all samples from the People's Republic of China. Serum samples from patients from an outbreak of ADRV had elevated titers to ADRV 3 and 16 months after the onset of symptoms. These findings, as well as other epidemiologic findings on ADRV, suggest that the organism is an important and continuing cause of diarrhea in the People's Republic of China, was present before the first epidemic in 1982, and represents a risk to surrounding populations in Asia.

Adult↗

Primary sclerosing cholangitis--a report of 2 cases.

Primary Sclerosing Cholangitis (PSC) is a rare cholestatic condition seen locally. Its etiology is unknown and it is commonly associated with ulcerative colitis, another rare condition seen locally. In this report, 2 patients with PSC, both Indian males, had ulcerative colitis and in one PSC was diagnosed some 15 years later. An interesting feature common to both patients was that of intra-hepatic ductal involvement. Percutaneous transhepatic cholangiogram (PTC) and Endoscopic Retrograde Cholangio-Pancreatogram (ERCP) showed characteristic stricturing and beading of the intra-hepatic ducts.

Adult↗

Early gastric cancer in Singapore.

A study was carried out on 41 cases of early gastric cancer over a five year period (1983-1987) based on resected stomach specimens. Males (29) outnumbered females (12) by 2.4:1. Mean age was 63 years (Range 30-80 years), and there was an overwhelming Chinese preponderance (40, 97.6%). The indications for endoscopy were: dyspepsia (24, 58.5%), gastro-intestinal bleeding (14, 34.1%) and follow up of megaloblastic anaemia (3, 7.4%). The diagnosis of malignancy was unsuspected at endoscopy in 38 patients and the commonest finding was a chronic ulcer (35, 85.4%). Most of the lesions were located in the body (24, 58.5%) and along the lesser curvature (36, 87.8%). Depressed lesions (Type III and combined IIc + III) were the commonest macroscopic lesions. Intestinal type carcinoma was the commonest microscopic type (34, 82.9%). Submucosal infiltration was present in 19 (47.3%) and lymph node metastases in 4 (9.8%). There was only one death from carcinoma of the stomach (mortality 2.4%).

Adenocarcinoma↗

Diarrheal deaths in American children. Are they preventable?

We reviewed national mortality data for 1973 through 1983 to assess the importance of diarrheal diseases as a cause of preventable childhood death in the United States. An average of 500 children aged 1 month to 4 years died each year with diarrhea reported as the cause of death. These diarrheal deaths were most common among children who were younger than 1 year of age, black, and living in the South, and were most common during the winter. In Mississippi, review of fatal cases of diarrhea identified maternal factors--black race, young age, unmarried status, low level of education, and little prenatal care--to be most associated with diarrheal death in the child. Fifty percent of these deaths occurred after a child had reached a medical facility. Our findings suggest that diarrheal deaths may be preventable and that targeted interventions could contribute to improved child survival in the United States.

Age Factors↗

Outbreak of echovirus 11 infection in hospitalized neonates.

Between July 18 and August 5, 1986, a cluster of echovirus 11 infections occurred in hospitalized neonates. Ten infants were affected and one died. All cases occurring after the index case were infants who were in the nursery for at least 1 day when the index patient was also present. Risk factors for secondary infection included low birth weight or gestational age and receipt of antibiotics, red blood cell transfusions, nasogastric intubation or gavage feedings. Because viral infection had not been suspected in the index patient, isolation measures were not instituted until after onset of secondary cases. We conclude that more severely ill infants receiving intensive levels of care are at increased risk for nosocomial enteroviral infection. These infants may have a greater likelihood of exposure to the virus and/or increased host susceptibility. Outbreaks caused by cross-infection may be preventable by early recognition of patients colonized or infected with potentially pathogenic agents and prompt institution of appropriate isolation measures.

Adolescent↗

Ulcerative colitis in Singapore: a clinical study of sixty-one patients.

Sixty-one consecutive cases of ulcerative colitis from the Department of Medicine, Singapore General Hospital, over a 16-year period (1971 to 1986) were reviewed. Mean duration of follow-up was 35.9 months (range 2 months to 16 years). Fifty-one (83.6%) cases were diagnosed in the last 8 years. Sex ratio was almost equal (males 30, females 31) and mean age was 38.2 years. All racial groups were affected but a predilection among Indians (21.3%) was observed. At presentation, the disease was mild in 36 (59.0%), moderate in 14 (22.9%) and severe in 11 (18.1%) patients. Fifty-two (85.2%) patients had symptoms of at least one month's duration before presentation. The 3 commonest symptoms were haematochezia (95.1%), diarrhoea (95.1%) and mucoid stools (83.6%). Extraintestinal manifestations of disease such as backache (8.2%), peripheral arthritis (6.5%), iritis (6.5%) and liver disease (1.6%) were uncommon. Severe intestinal complications include toxic megacolon (1.6%), colonic perforation (1.6%) and massive gastrointestinal haemorrhage (1.6%). Haematological and biochemical indices at presentation generally reflected the activity and severity of disease. The disease was limited to the rectum and sigmoid colon in 12 (19.7%) patients, extended up to the splenic flexure in 16 (26.2%), up to the hepatic flexure in another 16 (26.2%) and involved the whole colon in 17 (27.9%). Pseudopolyposis was present in 13 (21.3%) patients. Of 49 patients: (a) 18 (36.7%) had remission and were relapse free subsequently (b) 14 (28.6%) had infrequent relapses (less than 3 x/year) (c) 3 (6.1%) had frequent relapses (greater than 3 x/year) (d) 10 (20.4%) had chronically active disease (e) 4 (8.2%) had a short fulminant course terminating in death.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Ischaemic colitis in systemic lupus erythematosus--report of a case and review of the literature.

We report a case of perforation of the colon from systemic lupus erythematosus (SLE) presenting initially with diarrhoea and later with acute abdominal symptoms. She was found to have widespread arteriolitis involving the colon resulting in necrosis, ulceration and perforation with peritonitis and ultimately, death from septicaemia. Although intra-abdominal symptoms are not uncommon in cases of SLE, actual involvement of the gastrointestinal tract of a degree severe enough to warrant surgical intervention is a relatively uncommon phenomenon.

Adult↗

Crohn's disease--a diagnostic rarity in Singapore.

Nine cases of Crohn's disease from the Department of Medicine, Singapore General Hospital were collected over a duration of 9 years (1978-1986). Male (5): Female (4) ratio was nearly equal. Predominantly young people (mean age 30.5 year, range 12-59 year) from all races in Singapore were affected. Presentation could be acute (1), subacute (2), or chronic (6). The commonest symptoms were abdominal pain (8) diarrhoea (6) and weight loss (6). Three patients had a palpable right iliac fossa mass, 3 had definite malabsorption from ileal disease and 1 had perianal involvement leading to an anal stricture. The only extraintestinal manifestations of disease were clubbing and sacroiliatis. Haematological (haemoglobin, total white count, erythrocyte sedimentation rate) and biochemical (albumin) parameters generally reflected the degree of activity and chronicity of disease prior to presentation. The diagnosis and assessment of disease sites were based on a combination of radiological, endoscopic, operative and histological criteria. Ileal disease (4) per se was commonest followed by ileocolic disease (3) and colonic disease (2). Medical treatment consisted of sulphasalazine +/- steroids in all patients. Azathioprine and metronidazole were used for steroid sparing and perianal disease respectively. Laparotomy was performed in 2 patients. Six patients were well with infrequent (less than or equal to 2 times/year) or no relapses during follow up. Of the remaining three, 2 had either chronically active disease or frequent relapses (greater than 2 times/year) and one severe recurrent disease despite repeated gut resection.

Adolescent↗

The varied manifestations of abdominal tuberculosis.

Eight cases of abdominal tuberculosis from the Department of Medicine, Singapore General Hospital are reported to illustrate the varied clinical manifestations of the disease. Presentation ranged from asymptomatic hepatomegaly to acute abdomen (intestinal obstruction/perforation). Chronic non-specific symptomatology (fever, weight loss, abdominal pain, diarrhoea, jaundice) was commonest. There were three patients with hepatic tuberculosis, two with tuberculous mesenteric lymphadenitis and three with intestinal tuberculosis, two of whom had concomitant tuberculous peritonitis. Only three patients had coexisting pulmonary tuberculosis. The diagnosis was unsuspected at presentation in four patients. Initial provisional diagnoses included typhoid, abdominal lymphoma, hepatic malignancy, chronic hepatitis and iatrogenic gut perforation. All patients responded totally to conventional antituberculous therapy.

Adult↗