Explore the vast range of titles available.

Dengue is hyperendemic in Brazil and is underestimated by passive surveillance. To better understand dengue incidence, we conducted epidemiologic analyses among participants, 2-59 years of age, from the placebo arm of a phase 3 dengue vaccine trial. During 2016-2021, a total of 5,947 participants contributed to 22,028 person-years of follow-up. We identified and virologically confirmed dengue (VCD), Zika, and chikungunya infections. We observed VCD and chikungunya incidence heterogeneity by age, geographic location, and study year. Children 2-6 years of age experienced the highest VCD (2.33/100 person-years) and chikungunya (1.02/100 person-years) incidence. VCD peaked in 2019 (n = 148) whereas chikungunya peaked in 2017 (n = 51). VCD incidence rates from active surveillance were generally higher than those reported to the national passive surveillance system; expansion factor range was <1-9.5 by municipality. Active surveillance is critical to better understand and characterize dengue epidemiology.

Background Bovine Herpesvirus-1 (BoHV-1) is endemic in the Irish cattle population, but there is no current formal eradication programme for this disease in the Republic of Ireland. This observational, prospective field study is aimed to assess the evolution of the BoHV-1 seroprevalence on fifteen Irish dairy farms (85–250 cows) between 2020 and 2023 following the implementation of a hyperimmunisation IBR vaccination programme. Eligible farms had positive bulk tank results and estimated within-herd seroprevalence ≥ 25%. Animals from three months of age received a live, monovalent, double-deleted (gE-/tk-) marker vaccine (six-monthly boosters). Annually, biosecurity was evaluated using a 44-item survey. Each year, approximately 20 randomly selected animals per farm (4 calves, 4 heifers, 12 cows) were tested by gE-ELISA; in addition, animals with a negative result were retested in subsequent years ( N  = 818 animals). Seroprevalence was analysed using a logistic regression model with year and the epidemiological unit (calf, heifer or cow) as response variables, and farm as a random effect. A Pearson correlation between within-herd seroprevalences and biosecurity scores was also performed. Results The overall estimated animal level seroprevalence decreased from 55.7% to 37.2% after one year and was maintained at 37.5% after two years. Among the eleven herds that followed the hyperimmunisation IBR vaccination protocol, the estimated animal level seroprevalence was reduced from 57.3% to 33.6%, and the estimated within-herd seroprevalence from 54.5% to 22.2% within the study period. Reductions were most evident in calves (72.0%) and heifers (76.6%), compared with adult cows (33.1%). A significant negative correlation was observed between within-herd seroprevalences and biocontainment scores ( R = -0.51, p  < 0.001). Most retested animals maintained a seronegative status across the study period. However, data on culling and replacement rates were not available on the studied farms. Conclusion The control and eradication of BoHV-1 from the Republic of Ireland present many challenges to the Irish dairy industry. The results suggest that the maintenance of a hyperimmunisation protocol with an IBR gE-/tk- marker vaccine contribute to effectively and efficiently reducing BoHV-1 seroprevalence within the Irish dairy sector at farm level. Further large-scale controlled studies are required to confirm its role in national eradication strategies.

A nationwide survey of SARS-CoV-2 antinucleocapsid seroprevalence among blood donors in Japan revealed that, as of November 2022, infection-induced seroprevalence of the population was 28.6% (95% CI 27.6%-29.6%). Seroprevalence studies might complement routine surveillance and ongoing monitoring efforts to provide a more complete real-time picture of COVID-19 burden.

To determine a demographic overview of orthopoxvirus seroprevalence, we tested blood samples collected during 2003-2019 from France (n = 4,876), Bolivia (n = 601), Laos (n = 657), and Mali (n = 255) for neutralizing antibodies against vaccinia virus. In addition, we tested 4,448 of the 4,876 samples from France for neutralizing antibodies against cowpox virus. We confirmed extensive cross-immunity between the 2 viruses. Seroprevalence of antibodies was <1% in Bolivia, <5% in Laos, and 17.25% in Mali. In France, we found low prevalence of neutralizing antibodies in persons who were unvaccinated and vaccinated for smallpox, suggesting immunosenescence occurred in vaccinated persons, and smallpox vaccination compliance declined before the end of compulsory vaccination. Our results suggest that populations in Europe, Africa, Asia, and South America are susceptible to orthopoxvirus infections, which might have precipitated the emergence of orthopoxvirus infections such as the 2022 spread of monkeypox in Europe.

We evaluated human Crimean-Congo hemorrhagic fever virus (CCHFV) seroprevalence in hunter-gatherer populations of northeastern Democratic Republic of the Congo. We tested blood from 300 participants for CCHFV antibodies; 4% were CCHFV-positive. CCHFV likely has been circulating undetected in the country, indicating the need for a more robust surveillance system.

Bats are reservoirs for emerging human pathogens, including Hendra and Nipah henipaviruses and Ebola and Marburg filoviruses. These viruses demonstrate predictable patterns in seasonality and age structure across multiple systems; previous work suggests that they may circulate in Madagascar's endemic fruit bats, which are widely consumed as human food. We aimed to (a) document the extent of henipa‐ and filovirus exposure among Malagasy fruit bats, (b) explore seasonality in seroprevalence and serostatus in these bat populations and (c) compare mechanistic hypotheses for possible transmission dynamics underlying these data. To this end, we amassed and analysed a unique dataset documenting longitudinal serological henipa‐ and filovirus dynamics in three Madagascar fruit bat species. We uncovered serological evidence of exposure to Hendra‐/Nipah‐related henipaviruses in Eidolon dupreanum, Pteropus rufus and Rousettus madagascariensis, to Cedar‐related henipaviruses in E. dupreanum and R. madagascariensis and to Ebola‐related filoviruses in P. rufus and R. madagascariensis. We demonstrated significant seasonality in population‐level seroprevalence and individual serostatus for multiple viruses across these species, linked to the female reproductive calendar. An age‐structured subset of the data highlighted evidence of waning maternal antibodies in neonates, increasing seroprevalence in young and decreasing seroprevalence late in life. Comparison of mechanistic epidemiological models fit to these data offered support for transmission hypotheses permitting waning antibodies but retained immunity in adult‐age bats. Our findings suggest that bats may seasonally modulate mechanisms of pathogen control, with consequences for population‐level transmission. Additionally, we narrow the field of candidate transmission hypotheses by which bats are presumed to host and transmit potentially zoonotic viruses globally. In this paper, the authors (a) expand globally on the known range of bat hosts for henipaviruses and filoviruses, (b) demonstrate seasonal patterns in population‐level seroprevalence and individual‐level serostatus for Malagasy fruit bats and (c) use mechanistic models to reveal the critical role of waning humoral immunity in serological dynamics.

SARS-CoV-2 can infect domestic animals such as cats and dogs. The zoonotic origin of the disease requires surveillance on animals. Seroprevalence studies are useful tools for detecting previous exposure because the short period of virus shedding in animals makes detection of the virus difficult. We report on an extensive serosurvey on pets in Spain that covered 23 months. We included animals with exposure to SARS-CoV-2-infected persons, random animals, and stray animals in the study. We also evaluated epidemiologic variables such as human accumulated incidence and spatial location. We detected neutralizing antibodies in 3.59% of animals and showed a correlation between COVID-19 incidence in humans and positivity to antibody detection in pets. This study shows that more pets were infected with SARS-CoV-2 than in previous reports based on molecular research, and the findings highlight the need to establish preventive measures to avoid reverse zoonosis events.

We describe the seroprevalence of severe fever with thrombocytopenia syndrome virus (SFTSV) and the association of antibody occurrence with location, sex, and age among the human population in Pakistan. Our results indicate substantial activity of SFTSV and SFTSV-related viruses in this country.