Household Transmission of Rotavirus in a Community with Rotavirus Vaccination in Quininde, Ecuador

Background: We studied the transmission of rotavirus infection in households in peri-urban Ecuador in the vaccination era. Methods: Stool samples were collected from household contacts of child rotavirus cases, diarrhea controls and healthy controls following presentation of the index child to health facilities. Rotavirus infection status of contacts was determined by RT-qPCR. We examined factors associated with transmissibility (index-case characteristics) and susceptibility (householdcontact characteristics). Results: Amongst cases, diarrhea controls and healthy control household contacts, infection attack rates (iAR) were 55%, 8% and 2%, (n = 137, 130, 137) respectively. iARs were higher from index cases with vomiting, and amongst siblings. Disease ARs were higher when the index child was ,18 months and had vomiting, with household contact ,10 years and those sharing a room with the index case being more susceptible. We found no evidence of asymptomatic infections leading to disease transmission. Conclusion: Transmission rates of rotavirus are high in households with an infected child, while background infections are rare. We have identified factors associated with transmission (vomiting/young age of index case) and susceptibility (young age/sharing a room/being a sibling of the index case). Vaccination may lead to indirect benefits by averting episodes or reducing symptoms in vaccinees

Prevalence of Helicobacter pylori genotypes: cagA, vacA (m1), vacA (s1), babA2, dupA, iceA1, oipA and their association with gastrointestinal diseases. A cross-sectional study in Quito-Ecuador

Abstract Background The most prevalent stomach infection in the world is caused by Helicobacter pylori (H. pylori). Several pathogenicity genes, including cagA, vacA, babA2, dupA, iceA, and oipA, are associated with an increased risk of gastrointestinal disease such as peptic ulcer and stomach cancer. This research aims to determine the prevalence of different H. pylori genotypes and correlate their risk in the development of gastrointestinal diseases in the Ecuadorian population. Methods A cross-sectional research of 225 patients at the Calderón Hospital in Quito, Ecuador, was conducted. End point PCRs were run to determine the presence of 16S rRNA, cagA, vacA (m1), vacA (s1), babA2, dupA, iceA1, and oipA virulence genes. Chi-square test, odds ratios (OR) and 95% confidence intervals (CI) were utilized for the statistical analysis. Results H. pylori infection was present in 62.7% of people. Peptic ulcers were seen in 22.2% and malignant lesions in 3.6% of patients. Genes oipA (93.6%), vacA (s1) (70.9%), and babA2 (70.2%) were the most prevalent. cagA/vacA (s1m1) and cagA/oipA (s1m1) combinations were found in 31.2% and 22.7% of the cases, respectively. Acute inflammation has a significant correlation with the genes cagA (OR = 4.96 95% CI: 1.1–22.41), babA2 (OR = 2.78 95% CI: 1.06–7.3), and the cagA/oipA combination (OR = 4.78, 95% CI: 1.06–21.62). Follicular hyperplasia was associated with iceA1 (OR = 3.13; 95% CI: 1.2–8.16), babA2 (OR = 2.56; 95% CI: 1.14–5.77), cagA (OR = 2.19; 95% CI: 1.06–4.52), and the cagA/oipA combination (OR = 2.32, 95% CI: 1.12–4.84). The vacA (m1) and vacA (s1m1) genes were associated with gastric intestinal metaplasia (OR = 2.71 95% CI: 1.17–6.29) (OR = 2.33 95% CI: 1.03–5.24). Finally, we showed that cagA/vacA (s1m1) gene combination increased the risk of duodenal ulcer development (OR = 2.89, 95% CI 1.10–7.58). Conclusion This study makes a significant contribution by offering genotypic information regarding H. pylori infection. The presence of several H. pylori genes was associated with the onset of gastrointestinal illness in the Ecuadorian population

Disease attack rates^* amongst household contacts by their own characteristics and index case characteristics.

*<p>There was not sufficient power to fit regression model when using the definition of disease of symptomatic and RT-qPCR positive, as only 8 contacts met this definition. However, the simple frequency tabulations with this outcome were consistent with the disease (regardless of test result) outcome analysis. Attack rates were higher from children who were younger (24% (6/25) from children <18 months compared to 2% (2/106) from children ≥18 months), had multiple episodes of vomiting (15% (8/82) compared to 0% from children with 1 or no episodes of vomiting (0/79)) and amongst contacts aged less than 10 years (27% (7/26) compared to contacts aged 10 years or older (0%; 0/91)).</p><p>Odds ratios, 95% confidence intervals and Wald-test p values are given for (a) univariate models, multivariate models of (b) other case <i>or</i> contact characteristics and (c) other case <i>and</i> contact characteristics.</p

Infection and disease households with a rotavirus index case.

<p>Each line represents infection and disease events in one household. Index cases are plotted in black (n = 39). Other cases of rotavirus gastroenteritis in the household are plotted in red and are plotted on the time axis in terms of time of onset relative to time of onset of the index case. Household contacts with asymptomatic infection are plotted in blue (off the time scale, since we cannot know at what time they become infected) and contacts remaining uninfected are plotted in grey. The size of the points are relative to the number of individuals with a given outcome; for reference the size of the index cases (black dots) represents a single individual.</p

Calendar month distribution of index cases (n = 39) diarrhea controls (n = 40) and healthy controls (n = 40).

<p>Calendar month distribution of index cases (n = 39) diarrhea controls (n = 40) and healthy controls (n = 40).</p

Genotype (G- and P-type) profiles of infections amongst rotavirus index cases and household contacts.

<p>The first 2 columns represent the G and P types (respectively) of the typeable index cases (n = 35) and, with each typeable household contact (n = 57) shown to the right of the index case. Single G and P-tpye infections are color-coded; mixed infections are in black and un-typeable G- or P-types are in grey.</p

Infection (grey) and disease (red) attack rates amongst household contacts of index cases for (A) case characteristics and (B) contact characteristics.

<p>Infection (grey) and disease (red) attack rates amongst household contacts of index cases for (A) case characteristics and (B) contact characteristics.</p