Epidemiology and transmission of rotavirus infections and diarrhoea in St. Lucia, West Indies

To determine the epidemiology and risk factors of rotavirus in St. Lucia, 229 children in three valleys with varying levels of sanitation were studied for 2 years. A four-fold rise in complement fixation antibody to rotavirus antigen was used in paired samples as evidence of recent infection. Results showed that forty-eight per cent of infants experienced at least one infection during a two-year period, and 17 percent of children were reinfected. Infections occured within the first months of life and peaked between 6 and 23 months of age. The peak infection coincided with the dry season in each age group. Children breast-feeding had fewer infections. Although crowding within the home was significantly associated with repeated infection, the incidence of infection was not affected by the degree of sanitation. Other studies in the region, using recently developed techniques, concur with these findings which advance our understanding of the epidemiological importance of rotavirus in St. Lucia. Although these studies provide insights into the risk factors for rotavirus infections, other studies are required to determine whether investments should be focused on improved sanitation or immunization or both (AU)

Epidemiology and transmission of rotavirus infections and diarrhoea in St. Lucia, West Indies

To determine the epidemiology and risk factors of rotavirus in St. Lucia, 229 children in three valleys with varying levels of sanitation were studied for 2 years. A four-fold rise in complement fixation antibody to rotavirus antigen was used in paired samples as evidence of recent infection. Results showed that forty-eight per cent of infants experienced at least one infection during a two-year period, and 17%of children were reinfected. Infections occured within the first months of life and peaked between 6 and 23 months of age. The peak infection coincided with the dry season in each age group. Children breast-feeding had fewer infections. Although crowding within the home was significantly associated with repeated infection, the incidence of infection was not affected by the degree of sanitation. Other studies in the region, using recently developed techniques, concur with these findings which advance our understanding of the epidemiological importance of rotavirus in St. Lucia. Although these studies provide insights into the risk factors for rotavirus infections, other studies are required to determine whether investments should be focused on improved sanitation or immunization or both

Incidence and etiology of infantile diarrhea and major routes of transmission in Huascar, Peru.

Community-based studies of diarrhea etiology and epidemiology were carried out from July 1982-June 1984 in 153 infants residing in a poor peri-urban community near Lima, Peru. Study infants had nearly 10 episodes of diarrhea in their first year of life. Diarrhea episodes were associated with organisms such as Campylobacter jejuni, enterotoxigenic and enteropathogenic Escherichia coli, Shigella, rotavirus, and Cryptosporidium. These organisms appeared to be transmitted to infants in the home through animal feces, through contaminated water and food, and by direct person-to-person contact. A particularly important route of transmission may have been weaning foods, which were often contaminated because of improper preparation and inadequate cleaning of utensils. Improved feeding practices, along with avoidance of animal feces and improved personal and domestic hygiene, should be considered important interventions in reducing the high incidence of diarrhea in infants in developing countries.

The faecal coliform fingertip count: a potential method for evaluating the effectiveness of low cost water supply and sanitation initiatives.

A rapid and simple procedure for the enumeration of faecal coliform bacteria present on the fingertips is described. The distribution of individual faecal coliform fingertip counts within households has been compared with a number of variables related to the availability of water supply and sanitation facilities. This showed a strong association between the fingertip count and the possession of in-house water connections. It is proposed that this test might provide a reliable indication of the effectiveness of certain public health interventions.

Etiology and epidemiology of diarrheal diseases in the United States.

Accurate data on the frequency of acute diarrheal illness and the distribution of pathogens are not available for several reasons, including the facts that only a small fraction of cases come to the attention of physicians and that available diagnostic tests establish an etiology in only about half of these. In a survey of three groups of patients in a community (upper-middle class and lower class outpatients and hospitalized infants), a possible cause was found in fewer than 20 percent of outpatients, and rotavirus accounted for the majority. However, asymptomatic colonization with rotavirus is very common in early infancy, and demonstration of the antigen correlates with a causative role in diarrhea in only about one half of cases. Data on cases of shigellosis over a 15-year period in Dallas compared with the Centers for Disease Control national data demonstrate that epidemiologic patterns in any given community can differ substantially from the national data. Day-care centers are important sources of Giardia and Shigella infections in the community. The epidemiologic roles of newly reported causes of diarrhea (Campylobacter laridis, Blastocystis hominis, Cryptosporidium species, and Aeromonas hydrophila) are being explored. Generalizations about etiology and epidemiology of pathogens in diarrheal disease are invalid unless the population group is defined socioeconomically and geographically.

Vertical transmission of enteric pathogens at birth.

To determine how frequently mothers infect their infants with enteric pathogens at birth, stools were collected from 75 Thai mothers immediately before delivery and from their infants 24-48 h later. Enteropathogenic Escherichia coli (EPEC) were isolated from 25 of the 75 mothers just prior to delivery (32%), enteroviruses from six (8%), enterotoxigenic E. coli from five (7%), and shigella, salmonella and Vibrio parahaemolyticus each from one (1%). EPEC serotype 0128:K67 was isolated from one mother and from her infant, neither of whom had diarrhoea. Cultures from the other 74 mother-infant pairs did not detect identical enteric pathogens. Eighteen infants, nine of whose mothers submitted stools prior to delivery, developed diarrhoea within 5 days of birth. Five infants were infected with ETEC (28%), three with EPEC serotype 020a020cK61 (17%), one with Campylobacter jejuni (6%), and one with rotavirus (6%). None of these enteropathogens was found in 66 infants without diarrhoea. ECHO viruses of two different serotypes were isolated from two of 18 newborns with diarrhoea and unidentified enteroviruses from three of 66 without diarrhoea. Mothers and nurses are frequently infected with enteric pathogens in Thailand, but transmission to newborns at birth appears to be uncommon.

Studies of diarrhoea in Quindio (Colombia): problems related to water treatment.

This paper studies the association between fluctuations in rates of diarrhoea among children less than 5 years old in Armenia (Quindio) and variations in the application of chlorine in the aqueduct of the city. The study shows that to a great extent diarrhoea morbidity can be explained by the application of chlorine which does not reach useful levels of concentration during the required time. The article concluded by recommending the improvement of existing treatment plants and investing the necessary resources in new plants to insure the quality of water.

Survival and detection of rotaviruses on environmental surfaces in day care centers.

Previously, we demonstrated that children in day care centers commonly experience diarrhea due to rotavirus, giardia, and bacterial pathogens. Multiple agents frequently coexist, and the environment is heavily contaminated with enteric bacteria during outbreaks. A study of environmental surface contamination with rotavirus was performed during three non-outbreak periods. Of 25 samples collected from environmental surfaces and teachers hands at a day care center, 4 (16%) were positive for rotavirus antigen when a fluorescence assay was used. We also examined the survival of two animal viruses, rotavirus SA-11 and poliovirus type 1, and bacteriophage 12 on similar environmental surfaces in a laboratory. Poliovirus type 1 and bacteriophage f2 were more resistant to drying than rotavirus SA-11 and could be recovered after a 90-min exposure on a dry surface. Rotavirus SA-11 could be detected for 30 min. All three viruses survived longer when they were suspended in fecal material than when they were suspended in distilled water. These data suggest that several agents, including rotavirus, can remain viable on contaminated surfaces long enough to be transmitted to susceptible children. This finding helps explain why rotavirus shows a mode of spread like that of parasitic and bacterial agents within day care center settings.

Contamination of weaning foods and transmission of enterotoxigenic Escherichia coli diarrhoea in children in rural Bangladesh.

In longitudinal studies of infectious diseases and nutrition in Bangladesh, we determined the degree of bacterial contamination of traditional weaning foods and evaluated the role of these foods in the transmission of diarrhoeal diseases. 41% of samples of food items fed to weaning aged children contained Escherichia coli; these organisms were used as indicators of faecal contamination. Milk and foods prepared particularly for infants were more frequently and heavily contaminated with E. coli than was boiled rice, and E. coli levels were found to be related to the storage of cooked foods at high environmental temperatures. 50% of drinking water specimens also contained E. coli, but colony counts were approximately 10-fold lower than in food specimens. The proportion of a child's food samples that contained E. coli was significantly related to the child's annual incidence of diarrhoea associated with enterotoxigenic E. coli. This observation underscores the importance of seeking locally available foods that are hygienic as well as nutritious to supplement the diets of breastfeeding children in developing countries.

Enterotoxigenic Escherichia coli diarrhoea: acquired immunity and transmission in an endemic area.

Enterotoxigenic Escherichia coli (ETEC) are an important cause of diarrhoea in developing countries. Studies were made, in an endemic area of Bangladesh, of household contacts of patients with diarrhoea associated with E. coli producing heat-stable and heatlabile toxins (ST/LT) or heat-stable toxin (ST) only. It was found that 11% of contacts were infected in the 10-day study period, and that both the rate of infection and the proportion of infected persons with diarrhoea decreased with increasing age, suggesting the development of immunity. ETEC of the same serotype as that of the index patient were found in 9% of water sources used by index households, in a small number of food and drinking water specimens from the index homes, and in faeces from 3 healthy calves. The rate of infection of household members was highest in houses where there was contaminated food or water, which suggests that infection may take place in the home when contaminated water is brought in.

Viruses in the stools.

It has long been possible to isolate viruses from the stools by culture, though the viruses found are rarely implicated in disease of the gut. In contrast, only recently has it been possible to identify viruses in the stools of patients with diarrhoea. Initially, such identifications were made by electron microscopy but the unsuitability of the microscope for large-scale screening has led to the development of other methods. The new methods have concentrated on rotaviruses but other viruses are also implicated and an overall view of the significance of finding a virus in any stool specimen has to take into account the evidence about all viruses, old and new.

Reovirus-like agent as a cause of nosocomial diarrhea in infants.

Surveillance for nosocomial diarrhea due to a reovirus-like agent was maintained on the pediatric wards of a large metropolitan hospital in January and February, 1976, during a large community outbreak of that illness. During this period, 30 (27%) of 111 children under surveillance were admitted for dehydration secondary to diarrhea; 21 (70%) of these 30 children had RLA in stool samples obtained at admission. Ten (17%) of the 60 children admitted without diarrhea, hence at risk of acquiring nosocomial RLA infection, contracted the illness. With human RLA as an antigen, no hospital personnel had serologic (complement fixation test) evidence of infection. Early attempts to control the diarrhea at home and in the outpatient department by the use of oral fluid rehydration, isolation of patients with severe symptoms requiring hospitalization, and strict attention by hospital personnel to hand washing between examination of patients may limit nosocomial spread of the disease.