Pattern Of Seropositivity Research Articles

Hepatitis B Virus Serological Profile and Associated Risk Factors in Surface Antigen Negative Blood Donors in Nigeria

Background: This cross-sectional study investigated the serological profile, socio-demographic characters and risk factors of hepatitis B virus (HBV) infection among HBsAg-negative blood donors at the University of Abuja Teaching Hospital (UATH) Gwagwalada and Nnamdi Azikiwe University Teaching Hospital (NAUTH) Nnewi, Nigeria.Methods: Blood samples collected from 176 HBsAg-negative blood donors (96 from UATH and 80 from NAUTH) were screened using a commercially available HBV 5-Panel (CTK Biotech, USA) and anti-HBc IgM ELISA kits. Determination of HBV-DNA was done on 36 HBV positive and 100 negative samples using COBAS Roche Real-time qPCR. Structured questionnaires were used to collate subjects’ socio-demographic variables and risk factors of HBV infection. Results: Out of 176 samples tested, 140 (79.5%) were negative for HBV serologic markers while 36 (20.5%) were positive. The pattern of seropositivity showed that 19 (10.8%) samples were positive for anti-HBs, 9 (5.1%) were positive for anti-HBc, 3 (1.7%) were positive for both anti-HBc & anti-HBs and 5 (2.8%) were positive for anti-HBc IgM. None was positive for HBeAg and anti-HBe markers. Of the 36 HBV positive and 100 negative samples, 15 (41.7%) and 3 (3%) were positive for HBV-DNA respectively p=0.006. Not heard of HBV, no vaccination with HBV vaccines, previous blood transfusion, history of sexually transmitted diseases and visiting commercial barbers were significantly associated with HBV infection. Socio-demographic data showed that male blood donors were more infected with HBV than the females (p=0.284) and age group 26-40 years old was more affected than other age groups (p=0.015). Conclusions: The study revealed the endemicity of HBV infection and recommends that blood donors with critical risk factors be deferred from blood donation to reduce HBV transmission risk in Nigeria. Anti-HBc and anti-HBs markers could be included as screening tests for blood donors since HBV-DNA testing is not readily available and affordable.

Measles, Mumps, and Rubella Antibody: Patterns of Persistence and Rate of Decline Following the Second Dose of the MMR Vaccine

BackgroundAntibodies to measles, mumps, and rubella decline an estimated average of 3% per year, and have a high degree of variation among individuals. Yet, this variation and differences in individual-level response to the 3 antigens are not well understood. To better understand potential implications on individual and population-level susceptibility, we reanalyzed existing longitudinal data to identify patterns of seropositivity and antibody persistence.MethodsWisconsin children given the second dose of measles, mumps, and rubella vaccine (MMR2) at age 4–6 years were followed up to 12 years postvaccination. The rate of antibody decline and factors associated with the rate of decline were assessed using regression models that accounted for differences between and among subjects.ResultsMost of the 302 participants were seropositive throughout follow-up (96% measles, 88% mumps, 79% rubella). The rate of antibody decline was associated with MMR2 response and baseline titer for measles and age at first dose of MMR (MMR1) for rubella. None of the demographic or clinical factors examined were associated with rate of decline for mumps. One month after MMR2, geometric mean titer (GMT) to measles was high (3892 mIU/mL), but declined on average 9.7% per year among subjects with the same baseline titer and <2-fold increase in antibody titer after MMR2. Subjects with ≥2-fold increase experienced a slower decline (≤7.4%). GMT to rubella was 149 IU/mL one month after MMR2 and declined 2.6% and 5.9% per year among those who received MMR1 at 12–15 months and >15 months, respectively. GMT to mumps one month after MMR2 was 151 and declined 9.2% per year. Only 14% of participants had the same trends in antibody persistence for all 3 antigens.ConclusionThe rate of antibody decay varied substantially among individuals and among the 3 antigens. Despite waning titers, measles and rubella antibody levels remained high 12 years post MMR2. However, a fast rate of decline and high degree of variation was observed for mumps, yet no predictors of the decline were identified. Future research should focus on better understanding waning antibody titers to mumps and its impact on community protection and individual susceptibility, in light of recent mumps outbreaks in vaccinated populations.Figure 1.MeaslesFigure 2.MumpsFigure 3.RubellaDisclosures All authors: No reported disclosures.

What do we know about feline leishmaniosis?

According to the World Health Organization (WHO), endemic areas of leishmaniosis have spread and the number of reported cases has increased. Europe is one of the continents with greatest risk of the re-emergence of this zoonosis. The significance of the cat as a reservoir of Leishmania species and not simply an accidental host seems to be gaining ground, mainly because: (i) cats can present increased seropositivity between serological analyses, but the pattern of seropositivity is not consistent between cats; (ii) cats can be infected for some months and thus are available for sandflies; and (iii) cats transmit the Leishmania species agent in a competent form. Furthermore, cats have behavioural characteristics that contribute to infection by Leishmania infantum and, as such, feline leishmaniosis (FeL) has been reported worldwide. When clinical signs of FeL are present, they are non-specific and frequently occur in other feline diseases. If they go undiagnosed, they can contribute to an underestimation of the actual occurrence of the disease in cats. The low seroprevalence titres, along with the commonly asymptomatic infection in cats, can further contribute to the underestimation of FeL occurrence. This work aims to raise awareness about FeL among veterinarians by providing a review of the current status of FeL infection caused by L infantum worldwide, the major clinicopathological features of infection, along with recent developments on FeL diagnosis, treatment and prevention.

A relação entre soroprevalência de anticorpos contra o glicolipídeo fenólico-I entre crianças em idade escolar e endemicidade da hanseníase no Brasil

Leprosy control programs would benefit expressively from an easy method to estimate disease prevalence and to assess the effect of leprosy control measures on disease prevalence. Determination of the seroprevalence of antibodies to PGL-I through school children surveys might be a useful indicator of leprosy prevalence at the district level. To investigate whether seropositivity rates could be related to leprosy detection rates and whether seropositivity could be used as a proximal indicator to predict the leprosy incidence in other areas, 7,073 school children in three different leprosy-endemic states in Brazil were tested. The results show a widely varying distribution of seropositivity in the communities independent of the number of leprosy cases detected. Seroprevalence was significantly lower at private schools. No differences in the patterns of seropositivity between ELISA and dipstick were observed. No correlation between leprosy detection rate and seropositivity rates could be established.

Seroepidemiology of Toxoplasma gondii in pet dogs and cats in Beijing, China

AbstractSera from 534 pet dogs and 335 pet cats from Beijing (China) were tested for anti-Toxoplasma gondii antibodies using an enzyme-linked immunosorbent assay or the latex agglutination test. The seropositivity by year, season, sex and age was analysed. Overall, 128 dogs (24.0%) and 50 cats (14.9%) had antibodies to T. gondii. When analysed by season, the highest seroprevalence was found in spring for dogs (31.3%) and cats (25.1%), and the differences in seroprevalence by season was statistically significant in cats (P&lt;0.01) but not in dogs. The seroprevalence in male dogs (23.7%) and cats (15.1%) were slightly higher than their female counterparts (18.0% in dogs and 12.3% in cats). There was no obvious pattern of seropositivity or significant difference in different age groups in dogs or cats; nonetheless, a high proportion of dogs at 4 years of age were positive to T. gondii (31.8%) while cats with relatively high seropositivity rates were at 1 or 3.4 years of age (13.14%).