Human Astrovirus Outbreak in a Daycare Center and Propagation among Household Contacts

Abstract

We investigated an outbreak of acute gastroenteritis due to human astrovirus in a daycare center, describing the transmission mechanism, the most affected age groups, conditioning factors and the extent of the outbreak among household contacts of the daycare center attenders. Data were collected from persons exposed at the daycare center and their home contacts. Fecal samples from affected and non-affected daycare center attenders were analyzed for viruses causing acute gastroenteritis by RT-PCR. The percentage of households affected and the attack rates (AR) were calculated. The attack rates were compared using the rate ratio (RR) with 95% confidence intervals. Information was obtained from 245 people (76 attenders and 169 contacts) of whom 49 were clinical cases. Five HAstV-4, two HAstV-8 and three non-typable HAstV cases were identified (six from clinical cases and four from asymptomatic infected people). The global AR was 20% (41.2% in children aged < 2 years). Data were obtained from 67 households: 20 households of affected attenders and 47 of non-affected attendees. Household contacts of affected attenders had a higher AR (74.3%) than that of non-affected attendees (2.4%). We found asymptomatic infections amongst daycare attendees. The transmission of HAstV during the outbreak was not limited to the daycare center but extended to household contacts of both affected and non-affected attenders.

Common and Potential Emerging Foodborne Viruses: A Comprehensive Review

“…Astroviruses are spread worldwide, and they are accountable for 2-9% of acute, nonbacterial diarrheal illnesses in children, even though their occurrence in clinical specimens was higher and reached 61% in symptomatic and asymptomatic individuals [116,118,121]. In other works, it was found that human astrovirus causes 10% of acute gastroenteritis sporadic cases in children of <3 y, and that most outbreaks occurred mainly in healthcare and daycare centers, while in some developing countries, infection rates reached 20% [117]. The symptoms of gastrointestinal tract and inflammatory lesions affecting the meninges and brain tissue as encephalitis and meningitis were also reported [122,123].…”

“…Further, individuals infected with one strain do not acquire immunity against other strains. Globally, human astrovirus-1 and MLB-1 were the predominant genotypes detected in gastrointestinal tract infections [116][117][118][119]. Additionally, the most frequent viral co-infections reported with astrovirus illness involved norovirus and rotaviruses [120].…”