Diarrheal deaths in children living in New Mexico: toward a strategy of preventive interventions

Rotavirus mortality confirmed by etiologic identification in Venezuelan children with diarrhea

BACKGROUND

Hospital-based studies to determine the etiology of deaths from diarrhea are scarce. In this study, we specifically analyzed deaths due to rotavirus to assess the rotavirus impact on diarrhea mortality.

METHODS

To determine the rotavirus proportion contributing to mortality due to diarrhea, we analyzed data obtained from a hospital-based mortality surveillance, conducted over 7 years, in the Ciudad Hospitalaria Dr. Enrique Tejera, Valencia, Venezuela. Rotavirus was identified in stool samples collected from children who died of diarrhea, by a confirmatory ELISA and/or reverse transcription polymerase chain reaction.

RESULTS

Our results show that rotavirus (21%; 21/100) is the leading cause of death due to diarrhea among children <5 years of age; rotavirus also has an important impact (2%; 21/1336) on deaths from all causes in this age group. Shigella spp. (19%; 13/69) was the second most important cause of death, followed by calicivirus (6%; 3/53). Furthermore, this study documents a seasonal pattern in the deaths due to rotavirus (odds ratio 3.28; 95% confidence interval 1.13-9.76).

CONCLUSIONS

For Venezuela, it is estimated that approximately 300 children <5 years of age die of rotavirus each year, which means that 1 in 1800 children die by the age of 5. Rotavirus was found to be the main cause of death due to diarrhea, which supports previous estimations. This is the first study to present data of cause-specific mortality due to diarrhea based on hospital surveillance of diarrhea etiologies.

The pathology of rotavirus-associated deaths, using new molecular diagnostics

Rotavirus, the most common cause of severe, dehydrating gastroenteritis among children worldwide, annually causes approximately 500,000 deaths among children aged <5 years. The primary site of rotavirus infection is the small intestine. Pathologic investigations of patients who died of rotavirus infection are limited to data from a few reported autopsies, and dehydration with electrolyte imbalance is believed to be the major cause of death. Several recent reports suggest that children who died during a rotavirus illness were viremic before death, because rotavirus was detected at several extraintestinal sites. We report 3 rotavirus-associated deaths among children, 2 of whom had evidence of rotavirus genome in extraintestinal tissues detected by use of novel molecular diagnostic methods. The part played by rotavirus in fatal cases is unclear and requires additional investigation of diarrhea-associated deaths, because a better understanding might alter the approach to treatment and the need for antiviral therapy.

Foodborne viruses

Foodborne and waterborne viral infections are increasingly recognized as causes of illness in humans. This increase is partly explained by changes in food processing and consumption patterns that lead to the worldwide availability of high-risk food. As a result, vast outbreaks may occur due to contamination of food by a single foodhandler or at a single source. Although there are numerous fecal-orally transmitted viruses, most reports of foodborne transmission describe infections with Norwalk-like caliciviruses (NLV) and hepatitis A virus (HAV), suggesting that these viruses are associated with the greatest risk of foodborne transmission. NLV and HAV can be transmitted from person to person, or indirectly via food, water, or fomites contaminated with virus-containing feces or vomit. People can be infected without showing symptoms. The high frequency of secondary cases of NLV illness and - to a lesser extent - of hepatitis A following a foodborne outbreak results in amplification of the problem. The burden of illness is highest in the elderly, and therefore is likely to increase due to the aging population. For HAV, the burden of illness may increase following hygienic control measures, due to a decreasing population of naturally immune individuals and a concurrent increase in the population at risk. Recent advances in the research of NLV and HAV have led to the development of molecular methods which can be used for molecular tracing of virus strains. These methods can be and have been used for the detection of common source outbreaks. While traditionally certain foods have been implicated in virus outbreaks, it is clear that almost any food item can be involved, provided it has been handled by an infected person. There are no established methods for detection of viruses in foods other than shellfish. Little information is available on disinfection and preventive measures specifically for these viruses. Studies addressing this issue are hampered by the lack of culture systems. As currently available routine monitoring systems exclusively focus on bacterial pathogens, efforts should be made to combine epidemiological and virological information for a combined laboratory-based rapid detection system for foodborne viruses. With better surveillance, including typing information, outbreaks of foodborne infections could be reported faster to prevent further spread.

Rotavirus-associated medical visits and hospitalizations in South America: a prospective study at three large sentinel hospitals

BACKGROUND

Knowledge of the impact of rotavirus-associated disease on the health care systems of South America can aid in defining strategies for diagnosis, management and prevention. Up to date information on the impact of rotavirus disease in South America is scarce.

AIM

To determine prospectively the impact of rotavirus disease as a cause of medical visits and hospitalizations at three large sentinel pediatric hospitals in Argentina, Chile and Venezuela.

METHODS

A 2-year prospective surveillance for rotavirus-associated medical visits and hospitalizations was conducted during 1997 through 1998 at three large sentinel public hospitals, one each in Argentina, Chile and Venezuela. A common surveillance protocol was implemented at the three sites, and a representative number of nonbloody diarrhea stool samples from children <36 months of age were tested for rotavirus by enzyme-linked immunosorbent assay.

RESULTS

For our target age group, acute diarrhea-associated medical visits/hospitalizations represented 41%/2%, 5%/6% and 9%/13% of all medical visits/all hospitalizations at the Argentinean, Chilean and Venezuelan sites, respectively (P < 0.001 for difference among the three sites). Rotavirus detection rates among a total of 5,801/1,256 medical visit/hospitalization diarrhea stool samples tested were 39%/71% in Argentina, 34%/47% in Chile and 29%/38% in Venezuela (P < 0.01 by chi square for difference among the three sites). Rotavirus was associated with a mean of 1.5, 1.8 and 3% of total medical visits and 1.6, 2.8 and 5% of hospitalizations among children <36 months of age at the Argentinean, Chilean and Venezuelan sites, respectively. Seasonality was evident for medical visits at all three sites (although less striking in Chile) with peak activity occurring between November and May. Rotavirus-associated hospitalizations had a marked peak in Venezuela, represented largely by short stays, but not in Argentina and Chile.

CONCLUSIONS

Rotavirus was a significant cause of medical visits at all three sentinel sites. Rotavirus caused less hospitalizations than previously reported in Argentina and Chile. On the basis of our findings we estimate that approximately 106,000/ 21,000, 48,000/8,000 and 98,000/31,000 rotavirus-associated medical visits/hospitalizations occur yearly in Argentina, Chile and Venezuela, respectively.

Trends in diarrhea-associated hospitalizations among American Indian and Alaska native children, 1980-1995

OBJECTIVE

To describe trends in diarrhea- associated hospitalizations among American Indian and Alaska Native (AI/AN) children and to estimate the morbidity from rotavirus.

DESIGN

Retrospective analysis of Indian Health Service hospital discharge records.

PATIENTS

AI/AN children 1 month through 4 years of age with a diarrhea-associated diagnosis listed on the hospital discharge record.

SETTING

Hospitals on or near US Indian reservations from 1980 through 1995.

RESULTS

During 1980 through 1995, 21 669 diarrhea-associated hospitalizations were reported among AI/AN children. The annual incidence of diarrhea-associated hospitalizations declined by 76% from 276 per 10 000 in 1980 to 65 per 10 000 in 1995. The median length of hospital stay decreased from 4 days during 1980-1982 to 2 days during 1993-1995. Diarrhea-associated hospitalizations peaked during the winter months (October through March), especially among children 4-35 months of age, with the peaks appearing first in the Southwest during October and moving to the East in March. In the early years of the study (1980-1982), the rate of diarrhea-associated hospitalizations among AI/AN children (236 per 10 000) was greater than the national rate (136 per 10 000). By the end of the study period (1993-1995), the rate for AI/AN children (71 per 10 000) was similar to the national rate (89 per 10 000), although the rate for AI/AN infants remained higher than the national rate for infants.

CONCLUSIONS

Diarrhea-associated hospitalization rates for AI/AN children have declined to a level similar to that of the national population. Rotavirus may be an important contributor to diarrheal morbidity among AI/AN children, underscoring the need for vaccines against this pathogen.

Dehydration deaths in infants and young children

Dehydration in developed countries is an uncommon but important mechanism resulting in the death of infants and children. The clinicopathological features of a series of 37 fatal dehydration cases autopsied at the Adelaide Children's Hospital over a 33-year period (1961-1993) are presented. Causative factors for dehydration included gastroenteritis (21 cases), gastroenteritis with high environmental temperature (one case), high environmental temperatures (six cases), neglect/failure to thrive (four cases), mental retardation/chromosomal abnormality (three cases), congenital adrenal hyperplasia (one case), and unsuspected cystic fibrosis (one case). The mean age at death was 11.4 months (range 2 weeks to 6.25 years; median 6 months; 95% confidence interval 6 months to 1 year and 4 months; male-to-female ratio, 19:18). Sixteen of the 22 cases of fatal gastroenteritis (73%) occurred during the fall/winter months (March to August). There were a total of seven aboriginal or part aboriginal children in the group (19%). Children with mental retardation were at higher risk of dehydration, and previously unsuspected cases of child abuse/neglect also presented with lethal dehydration. Vitreous humor electrolyte levels and immunoassay for rotavirus were useful diagnostic adjuncts.