Transmission Of Rotavirus Infection Research Articles

Non-linear effect of temperature variation on childhood rotavirus infection: A time series study from Kathmandu, Nepal

IntroductionThis study aimed to investigate the effects of temperature variability on rotavirus infections among children under 5 years of age in Kathmandu, Nepal. Findings may inform infection control planning, especially in relation to the role of environmental factors in the transmission of rotavirus infection. MethodsGeneralized linear Poisson regression equations with distributed lag non-linear model were fitted to estimate the effect of temperature (maximum, mean and minimum) variation on weekly counts of rotavirus infections among children under 5 years of age living in Kathmandu, Nepal, over the study period (2013 to 2016). Seasonality and long-term effects were adjusted in the model using Fourier terms up to the seventh harmonic and a time function, respectively. We further adjusted the model for the confounding effects of rainfall and relative humidity. ResultsDuring the study period, a total of 733 cases of rotavirus infection were recorded, with a mean of 3 cases per week. We detected an inverse non-linear association between rotavirus infection and average weekly mean temperature, with increased risk (RR: 1.52; 95% CI: 1.08–2.15) at the lower quantile (10th percentile) and decreased risk (RR: 0.64; 95% CI: 0.43–0.95) at the higher quantile (75th percentile). Similarly, we detected an increased risk [(RR: 1.93; 95% CI: 1.40–2.65) and (RR: 1.42; 95% CI: 1.04–1.95)] of rotavirus infection for both maximum and minimum temperature at their lower quantile (10th percentile). We estimated that 344 (47.01%) cases of rotavirus diarrhoea among the children under 5 years of age were attributable to minimum temperature. The significant effect of temperature on rotavirus infection was not observed beyond lag zero week. ConclusionAn inverse non-linear association was estimated between rotavirus incidence and all three indices of temperature, indicating a higher risk of infection during the cooler times of the year, and suggesting that transmission of rotavirus in Kathmandu, Nepal may be influenced by temperature.

Evidence of intrafamilial transmission of rotavirus in a birth cohort in South India

Transmission of rotavirus infection was studied in a birth cohort of children based in an urban slum in Vellore and their familial contacts. Contemporaneous samples from index patients and their familial contacts were collected for analysis in three different settings. Firstly, samples were collected from familial contacts during a period of rotavirus infection in children from the cohort. Secondly, on occasions when a family member had rotavirus diarrhea, samples from the cohort child were taken for analysis. Lastly, asymptomatic surveillance samples collected at predetermined time points from both the cohort child and familial contacts were analyzed. From 560 samples collected from family members during symptomatic and asymptomatic rotavirus infections in these children, three rotavirus transmissions were identified, accounting for a secondary attack rate of 0.54%. In four instances of rotavirus diarrhea in a family member, one infection was transmitted to the cohort child. Nucleotide sequence and phylogenetic analysis demonstrated a high degree of similarity in all these pairs ranging between 99% and 100% at both the nucleotide and the deduced amino acid levels, highly suggestive of person-to-person transmission of rotavirus infection. There was complete concordance of rotavirus genotyping between these pairs. No transmission events were noted from 14 asymptomatic rotavirus infections identified during routine surveillance of family members. This study is the first to use phylogenetic analysis to study the intrafamilial spread of rotavirus infection.

Investigation of the environment and of mothers in transmission of rotavirus infections in the neonatal nursery

A distinct feature of neonatal rotavirus infection is the association of unusual strains that appear to be prevalent only in neonatal units and persist for long periods of time. The main aims of this study were to determine if rotavirus can be detected on environmental surfaces in the neonatal nursery and whether the infection occurs in mothers of infected and uninfected neonates. Thirty rotavirus positive neonates and an equal number of negative neonates were enrolled in this study. Stool samples from 15 mothers in each group and environmental swabs collected from the bed and surfaces around neonates were tested for rotavirus using single round and nested PCR for the VP6 gene. Rotavirus could be detected in environmental swabs using single round PCR for VP6 gene in 40% of neonates positive for rotavirus antigen by enzyme immunoassay (EIA) and 33.3% of EIA negative neonates. The detection rate was almost 100% using the nested VP6 PCR. Rotavirus was detected in maternal samples only if the nested VP6 PCR was used, with no significant difference between rates of rotavirus detection in maternal fecal samples of infected and uninfected neonates (p-0.4). Sequence analysis of nested VP6 amplicons from two environmental swabs revealed them to be closest in identity to G10P[11], the most common genotype causing infections in neonates in this setting. Interestingly, sequences of amplicons from maternal stool samples did not cluster with G10P[11] or other VP6 subgroup I strains but showed clustering with human strains of VP6 subgroup II.

The Tecumseh Study. XVI: Family and community sources of rotavirus infection.

The effect of age on transmission of rotavirus infection within households and on the risk of infection from outside of the household was investigated through analyses of serum pairs. These paired specimens had been collected from individuals of all ages in families of diverse age composition in Tecumseh, Michigan. Serologic observations on 1,508 individuals divided into 0-1, 2-4, 5-9, 10-17, and 18+ year age groups provided infection determinations on 3,311 person-seasons during the 1977 through 1981 rotavirus seasons. Infection occurring in an individual in each age group was generally associated with infection in all other age groups in the household. Despite these associations by household, two different means of estimating the proportion of all infections acquired in the household yielded estimates of only 17 and 20%, indicating the importance of community acquisition of infection. Very young children had a very small percentage of their infections acquired in the household, while progressively older ages had an increasing percentage of infections acquired there. These results indicate that a strategy of indirectly protecting infants from infection by preventing infection in their household contacts would be inefficient.

Chemical disinfection of human rotavirus-contaminated inanimate surfaces.

Fomites may play a role in the transmission of rotavirus infections, and in view of this, 27 disinfectants were evaluated for their ability to inactivate human rotavirus (HRV) on contaminated non-porous inanimate surfaces. Disks of stainless steel, glass and two types of plastics were contaminated with about 10(7) plaque-forming units of HRV suspended in faecal matter. The inoculum was allowed to dry and an equal volume of the product under test was applied to the contaminated surface. After contact for 1 min, the action of the disinfectant was stopped by dilution. Surviving infectious virus on the disks was determined by plaque assay in MA-104 cells. A product was considered to be effective if it could reduce the virus titre by at least 3 log10. Only 33.3% (9/27) of the formulations tested proved to be effective. Further testing of the effective products, which included antiseptics, instrument soaks and hard-surface disinfectants, showed that all of them could, in fact, reduce the virus titre on contaminated surfaces by at least 6 log10. These findings show the relative resistance of HRV to a wide range of chemical disinfectants in common use, and also emphasize the need for a more thorough evaluation of the virucidal potential of formulations regularly employed in attempts to prevent and control outbreaks of rotaviral diarrhoea.

Institutional outbreaks of rotavirus diarrhoea: potential role of fomites and environmental surfaces as vehicles for virus transmission.

To assess the potential of fomites and environmental surfaces as vehicles in the transmission of rotaviral diarrhoea, disks (1 cm diameter) of various porous and non-porous materials were contaminated with about 10(5) plaque-forming units of the Wa strain of human rotavirus (HRV) suspended in faecal matter. The contaminated disks were then held for 10 days at either room temperature (22 +/- 2 degrees C) or 4 degrees C with the relative humidity (RH) at the high (85 +/- 5%), medium (50 +/- 5%) or low (25 +/- 5%) level. Survival was longer on non-porous surfaces at the lower temperature and at lower humidity. In contrast, survival on porous surfaces was very variable; better on cotton-polyester than on poster card or paper currency on which HRV survived very poorly. These results suggest that under the right environmental conditions, HRV-contaminated objects could play a role in the transmission of rotavirus infections in hospitals, nursing homes and day-care centres.

Occurrence of rota- and enteroviruses in drinking and environmental water in a developing nation

Rotaviruses have been implicated as a major cause of childhood and traveler's diarrhea in developing countries. Since water is known to be a vehicle of transmission of other enteric viruses, we sought to determine if water could play a role in the transmission of rotavirus infections in a developing nation by applying recently developed techniques for the concentration of viruses from tapwater and environmental (lake, river, ocean and aqueduct) water in Mexico. In an initial survey during the rainy season in August 1978, rotavirus was detected in 10 of 10 drinking water samples and coxsackie B4 or B6 virus in 5 of 10. In a larger survey during the dry season in December 1979, rotavirus was recovered from 3 and enteric viruses from 8 of 21 drinking water samples. Water quality data, available for the 1979 survey, indicated that while many tapwater samples did not meet U.S. coliform standards, some samples containing infectious virus did. Our data suggest that current bacteriological water quality standards for potable water do not reflect viral contamination.