Hepatitis E seroprevalence and associated factors in rural settlers in Central Brazil

<div><p>Abstract INTRODUCTION: Prevalence of hepatitis E virus (HEV) infection and associated factors were investigated in rural settlements in Central Brazil. METHODS: A total of 464 settlers were interviewed, and serum samples were tested for anti-HEV IgG/IgM. Positive samples were tested for HEV RNA. RESULTS: Sixteen participants (3.4%; 95% CI 2.0-5.7) were positive for anti-HEV IgG. None was positive for anti-HEV IgM. HEV RNA was not detected. Dwelling in a rural settlement for >5 years was associated with HEV seropositivity. CONCLUSIONS: The results revealed the absence of acute infection and a low prevalence of previous exposure to HEV.</p></div

Longitudinal Study of Hepatitis A Infection by Saliva Sampling: The Kinetics of HAV Markers in Saliva Revealed the Application of Saliva Tests for Hepatitis A Study

<div><p>Despite the increasing numbers of studies investigating hepatitis A diagnostic through saliva, the frequency and the pattern of hepatitis A virus (HAV) markers in this fluid still remains unknown. To address this issue, we carried on a longitudinal study to examine the kinetics of HAV markers in saliva, in comparison with serum samples. The present study followed-up ten patients with acute hepatitis A infection during 180 days post diagnosis (dpd). Total anti-HAV was detected in paired serum and saliva samples until the end of the follow-up, showing a peak titer at 90^th. However, total anti-HAV level was higher in serum than in saliva samples. This HAV marker showed a probability of 100% to be detected in both serum and saliva during 180 dpd. The IgM anti-HAV could be detected in saliva up to 150 dpd, showing the highest frequency at 30^th, when it was detected in all individuals. During the first month of HAV infection, this acute HAV marker showed a detection probability of 100% in paired samples. The detection of IgM anti-HAV in saliva was not dependent on its level in serum, HAV-RNA detection and/or viral load, since no association was found between IgM anti-HAV positivity in saliva and any of these parameter (p>0.05). Most of the patients (80%) were found to contain HAV-RNA in saliva, mainly at early acute phase (30^th day). However, it was possible to demonstrate the HAV RNA presence in paired samples for more than 90 days, even after seroconversion. No significant relationship was observed between salivary HAV-RNA positivity and serum viral load, demonstrating that serum viral load is not predictive of HAV-RNA detection in saliva. Similar viral load was seen in paired samples (on average 10⁴ copies/mL). These data demonstrate that the best diagnostic coverage can be achieved by salivary anti-HAV antibodies and HAV-RNA tests during 30–90 dpd. The long detection and high probability of specific-HAV antibodies positivity in saliva samples make the assessment of salivary antibodies a useful tool for diagnosis and epidemiological studies. The high frequency of HAV-RNA in saliva and the probability of detection of about 50%, during the first 30 dpd, demonstrate that saliva is also useful for molecular investigation of hepatitis A cases, mainly during the early course of infection. Therefore, the collection of saliva may provide a simple, cheap and non-invasive means of diagnosis, epidemiological surveys and monitoring of hepatitis A infection purposes.</p></div

Course of hepatitis A in patients followed during 180 days by serum and salivary diagnostic assays: observations for total anti-HAV (A), IgM anti-HAV (C), and viral load (E) and probabilities of positivity for total anti-HAV (B), IgM anti-HAV (D) and HAV-RNA (F).

<p>Solid lines and shaded areas along them represent for saliva the predicted mean values and 95% confidence intervals, whereas dashed lines and respective shaded areas represent for serum results the predicted mean values and 95% confidence intervals. In A-C-E, circles and triangles represent individual observations for saliva and serum, respectively, and in B-D-F, represent the counts of positive tests (value 1) or negative (value 0) for saliva and serum, respectively. Shape sizes (circles and triangles) are proportional to the counts.</p