Virus Seroprevalence Research Articles

Crimean Congo hemorrhagic fever virus exposure among febrile patients, cattle herders, and cattle herds in Cameroon

Problem addressedCrimean Congo hemorrhagic fever (CCHF) is a tick-borne disease with high fatality rates and an expansive geographic distribution, yet disease prevalence data in Cameroon is lacking. ObjectiveThis study aimed to determine CCHF virus (CCHFV) seroprevalence and tick distribution among cattle herders and febrile patients in West and Centre Cameroon. Methods and approachTwo cross-sectional serological studies of human and cattle were conducted from October to December 2021 and from June to July 2022, which included the collection of ticks. Enzyme-linked immunosorbent assay (ELISA) were used to detect anti-CCHFV antibodies, while a knowledge, attitudes, and practice (KAP) survey assessed tick and tickborne disease related knowledge and behaviors among herders. Tick identification used morphological keys. ResultsThe KAP survey showed adequate tick knowledge (94.5 %) among herders but poor understanding of disease transmission, with favorable attitudes towards tick control (24.7 %) but inadequate implementation. Rhipicephalus annulatus (64.1 %) predominated among the 1,296 ticks collected during each rainy season. Among cattle, 27.4 % were seropositive, and seropositivity was associated with specific villages, cattle age (>4 years), and female sex. Herders had a 17.8 % seroprevalence, while febrile patients had 8.3 %, with higher rates in those >20 years old for both groups. Self-reported tick removal by herders after contact and grazing may increase CCHFV exposure. ConclusionsThis study confirms CCHFV circulation in rural West Cameroon and unexpected exposure risk in Yaounde, highlighting the need for active entomological surveillance and preventive measures in transhumance and cattle market activities. Establishing an occupation-based surveillance system can help identify CCHFV hotspots to prevent outbreaks.

Seroprevalence of Arboviruses in Travelers in Morocco: Focus on Dengue and Zika

Dengue and Zika viruses belong to the arbovirus family and are emerging infectious diseases transmitted by Aedes mosquitoes, prevalent in tropical and subtropical regions. Their proliferation is facilitated by factors such as adaptability, climate change, and globalization. Despite surveillance efforts by the World Health Organization (WHO), global monitoring remains limited. This study aimed to ascertain the seroprevalence of these diseases among travelers returning from endemic regions. A prospective, cross-sectional study was conducted on 2023 targeted travelers in the Democratic Republic of Congo and the Central African Republic. Participants were selected based on specific criteria over a six-month period. Blood samples were assessed in our laboratory using the VirClia® automated chemiluminescence immunoassay to detect Dengue and Zika IgG and IgM antibodies. The analysis involved interpretation of the results using a specific formula. The study included a young, asymptomatic cohort, averaging 30.8 years of age. Travelers were categorized according to age, sex, and country of residence. Dengue virus seroprevalence was 18.6%, predominantly IgG. The prevalence of ZIKV infection was 12.9%. The seroprevalence of these arboviruses varies according to sociodemographic factors. Epidemiological studies play a crucial role in assessing the prevalence of vector-borne diseases and informing public health strategies to mitigate their global impact.

Seroprevalence of herpes simplex virus 2 infection among commercial sex workers in Colombo, Sri Lanka

Background: Herpes Simplex Virus Type 2 (HSV2) causes genital herpes, an incurable, lifelong sexually transmitted infection (STI). This study was conducted to describe the seroprevalence and associated factors of HSV2 infection in a cohort of Female Sex Workers (FSWs). Methods: A descriptive cross-sectional study was conducted on 136 FSWs who attended the central STD Clinic, in Colombo. They were assessed using an interviewer-administered questionnaire followed by serum sampling. Serum samples were tested for HSV2 IgG using an enzyme immunoassay specific for glycoprotein gG2 of HSV2. Results: HSV2 seroprevalence of FSW was 66.9% (91/136) of which only 14.3% (13/91) reported a history of genital infection. Age ≥35 years (OR 3.35, 95%CI 1.54-7.31, p=0.002), education ≥ grade 5 (OR 8.35, 95%CI 13.1- 64.7, p<0.001), lifetime sexual partners ≥ 200 (OR 5.33, 95% CI 2.3-12.36), p<0.001), duration of sex work ≥1 year (OR 4.5, 95% CI 2.09-9.65, p<0.001) and history of STI (OR 4.52, 95% CI 1.9-10.78, p<0.001) were statistically significant risk factors for high HSV2 prevalence. Consistent condom use by commercial partners in the last 3 months was not a significant protective factor in preventing HSV2 infection (OR 0.44, 95% CI 0.15-1.26, p = 0.12) in this cohort. Conclusions: The seroprevalence of HSV2 is high in this population and most of them did not report any genital infection. Multiple risk factors for higher prevalence were observed. Findings support the need for regular surveillance, monitoring of HSV-2 infection in high-risk populations, and expanding awareness of HSV-2 infection in the country.

Seroprevalence of human papilloma virus 6, 11, 16 and 18 among pregnant women in Mwanza-Tanzania

IntroductionHigh-risk human-papilloma viruses 16 and 18 (HR-HPV 16 and HR-HPV-18) are well known to be associated with carcinoma of the cervix, head and neck, penis, and anus. Low-risk human papillomaviruses 6 and 11 (LR-HPV 6 and LR 11) infection has been associated with anogenital warts, oral papilloma, and laryngeal papillomatosis in children. HPV infection during pregnancy (HR-HPV and LR-HPV) increases the risk of vertical transmission from infected pregnant women to unborn children. The burden of HR-HPV type 16 and 18 and LR-HPV 6 and 11 is not well documented among pregnant women attending antenatal clinics (ANC). This study determined the seroprevalence and distributions of HR-HPV 16, 18, and LR –HPV 6, 11 antibodies among pregnant women attending ANC at Bugando Medical Centre (BMC) in Mwanza, Tanzania.MethodologyA cross-sectional study involving 255 pregnant women enrolled in obstetrics and gynecology outpatient clinics was conducted between November 2020 and March 2021 at Bugando Medical Centre (BMC) in Mwanza. A structured pre-tested questionnaire was used to obtain patients’ information. Sandwich Enzyme-Linked Immunosorbent Assay (ELISA) was used to detect HPV 6, 11, 16 and 18 specific immunoglobulin G (IgG) from sera. Stata version 15v1 was used for the descriptive data analysis.ResultsThe median age was 27(IQR: 22–31) years. The overall HPV seropositivity for any of the four serotypes was 63.9% (165/255), 95% CI: 58.0-69.7, whereby 37.6%(97/255), 32.2%( 83/255), 15.5% (40/255) and 27.1% (70) were positive for HPV 6, 11, 16 and 18 respectively. Eight participants (3.1%) were positive for all 4 genotypes.ConclusionAbout two-thirds of pregnant women had antibodies against HPV 6, 11 16, and 18 indicating previous HPV exposure. Vaccination programs should be emphasized to reduce the HPV-related manifestations in this population.

Seroprevalence and associated risk factors of Peste des petits ruminants in selected districts of Awi zone, Northwest Ethiopia

A cross-sectional study to estimate the antibody seroprevalence of the PPR virus and determine the associated risk factors was conducted from February 2021 to May 2022 in the Guangua and Jawi districts of the Awi zone. Of the total 380 sera samples tested using cELISA, 231 (60.8 %) were found positive for the PPRV antibody. A significantly higher prevalence of 76.2 % (OR = 4.5, P = 0.000) was observed in the Jawi district than in the Guangua district (45.5 %). Seroprevalence of 61.9 % (109/176) in sheep and 59.8 % (122/204) in goats was also detected in the present study (P > 0.05). Significantly higher prevalence was revealed in old (69.7 %, OR = 3.4) and adult (65.7 %, OR = 2.3) age groups compared to young (48.9 %) age groups. A prevalence of 63.4 % and 55.6 % were reported in female and male animals respectively (P > 0.05, χ2 = 1.85). As evidenced by the serological test result, PPR is highly circulated in the Guangua and Jawi districts of the Awi zone. The higher circulation of the PPR virus, the uncontrolled movement of animals, and the regular practice of communal grazing systems in the area indicate the chance of continued dissemination within and to other places. Hence, proper implementation of prevention and control measures and further study on sequencing and characterization of the circulating virus are advised.

Seroprevalence and Molecular Analysis of Yellow Fever Virus in Mosquitoes at Namanga and Mutukula Borders in Tanzania

Yellow fever (YF) is a major public health concern particularly in Africa and South America. This study aimed to detect YF in human and mosquito samples to understand transmission dynamics in the Tanzania-Uganda and Tanzania-Kenya cross-border areas. Blood samples were collected from 9 months and older individuals for serological testing while mosquitoes were captured and tested for YF virus RNA. Logistic regression models were used to predict seroprevalence and associated risk factors. The overall YF seroprevalence was 12.5% with higher rates in older individuals (7.0%) and females (IgG 4.4%, IgM 6.0%). Notably, YF virus RNA was detected in three out of 46 pools of 192 mosquitoes. The odds of testing positive for YF IgG were lower among those with primary education compared with college education (AOR = 0.27, CI: 0.08-0.88) and increased with being female (AOR = 4.7, CI: 1.5-14.7), traveling to YF endemic areas (AOR = 5.2, CI: 1.35-44.75), exposure to Aedes mosquitoes (AOR = 3.7, CI: 1.27-10.84), experiencing muscle pain (AOR = 4.5, CI: 1.08-18.78), and exhibiting bruising (AOR = 13.5, CI: 1.23-145.72). Despite not experiencing YF outbreaks, Tanzania shows evidence of YF exposure in studied borders highlighting the need to strengthen cross border-surveillance, vector control, vaccination and further research to evaluate country overall YF risks.

Impact of COVID-19 Nonpharmaceutical Interventions on Bordetella pertussis, Human Respiratory Syncytial Virus, Influenza Virus, and Seasonal Coronavirus Antibody Levels: A Systematic Review.

During the COVID-19 pandemic, nonpharmaceutical interventions (NPIs) were introduced to reduce the spread of SARS-CoV-2. This also resulted in a reduction of notifications of other acute respiratory infections and an altered seasonality when NPIs were lifted. Without circulation of pathogens, waning of antibodies is expected, which is a first indicator of decreased immunity. Here, by performing a systematic literature review, we investigated whether reduced antibody levels due to waning immunity contributed to the altered seasonality after NPIs were lifted. Thirteen articles met the inclusion criteria and reported antibody levels or seroprevalence of human respiratory syncytial virus, seasonal human coronavirus, Bordetella pertussis, and influenza virus. We show that the COVID-19 pandemic most likely led to waning of pathogen-specific antibodies, with the strongest evidence for human respiratory syncytial virus and seasonal human coronavirus and with a larger decrease in children vs adults. Waning antibodies might have resulted in out-of-season activity for these pathogens.

Seroprevalence of Hepatic Viruses and Associated Risk Factors Among Rehabilitated Patients During the Post-Addictive Phase

Background: Drug addiction poses a major public health risk, particularly in terms of the transmission of blood-borne infections like Hepatitis B (HBV), Hepatitis C (HCV), and Human Immunodeficiency Virus (HIV) among users.Objective: To assess the seroprevalence of HBV, HCV, and HIV and identify associated risk factors among drug users in rehabilitation centers in Islamabad, Pakistan.Methods: A cross-sectional study was conducted on 203 drug users from July to October 2022. Participants were screened for HBV, HCV, and HIV using immunochromatographic tests (ICT) and confirmed by Enzyme-Linked Immunosorbent Assay (ELISA). Demographic and risk factor data were collected through structured forms. Statistical analysis was performed using SPSS version 20.0, including descriptive statistics and chi-square tests for associations.Results: The prevalence rates for HCV, HBV, and HIV were 15.8%, 9.3%, and 3.4%, respectively. Intravenous drug users showed a higher prevalence of HCV (8.4%) compared to non-intravenous users (7.4%). Needle sharing (55.7%) and low socio-economic status (83.2%) were significant risk factors.Conclusion: HCV is highly prevalent among drug users, especially intravenous users, necessitating targeted harm reduction strategies and enhanced rehabilitation facilities.

Seroprevalence of West Nile virus in equids in eastern Spain (2021–2023)

Seroprevalence of West Nile virus in equids in eastern Spain (2021–2023)

Hepatitis C Virus Seroprevalence and Genotypic Distribution Among Hemodialysis Patients at a Teaching and Training Hospital in Western Rajasthan, India.

Background Hepatitis C virus (HCV) infection is a chronic hepatotropic blood-borne infection. The transmission of HCV in patients undergoing hemodialysis (HD) is more common in comparison to the general population due to factors such as frequent blood transfusions, prolonged vascular access, and the potential for nosocomial infections. Western Rajasthan in India is home to numerous teaching and training hospitals that cater to a large number of HD patients. Understanding the seroprevalence and genotypic distribution of HCV in this specific patient population is crucial for assessing the extent of infection within this vulnerable group for targeted surveillance and developing effectively tailored treatment protocolsin healthcare settings. Hence, this study was conducted with an aim to determine seroprevalence, seroconversion, and genotypes of HCV in HD patients at a tertiary care hospital. Methods This was a cross-sectional observational study. The duration of the study was from July 2019 to March 2022. In this study, the patients undergoing maintenance HD due to chronic kidney disease (CKD) were recruited. The data collected include patients' demographics, etiology of CKD, underlying other co-morbidities, duration of dialysis, and biochemical and blood count parameters. The patients recruited at the start of the study were screened for anti-HCV antibodies by HCV enzyme-linked immune sorbent assay (ELISA). The anti-HCV antibody-negative patients were followed up for the detection of anti-HCV antibodies. At the end of the follow-up period, all anti-HCV antibody negative samples in the pool of five and all anti-HCV antibody positive samples were subjected to a real-time polymerase chain reaction (RT-PCR) of 5' untranslated region (5'UTR) and core region, followed by line probe assay (LiPA). Results In this study, after applying inclusion and exclusion criteria, a total of 109 patients were recruited, out of which 64 (58.7%) were males and 45 (41.3%) were females. The age range of participants was 11-88 years with a mean and standard deviation of 46.75 and 16.35 years, respectively. A total of 39 patients (20 on screening, 19 on follow-up) were detected anti- HCV antibody positive. By RT-PCR, 24 patients tested HCV RNA positive (10 on screening, 14 on follow-up). Among 24 HCV RNA-positive samples, LiPA showed, HCV genotype 1a (n=21), genotype 3b (n=1), and two samples were detected to be inconclusive. Conclusion The increasing duration of dialysis is significantly associated with acquiring HCV infection. The majority of the cases of CKD in this geographical region are due to hypertensive nephropathy. There can be discordance between antibody and viral RNA positivity in HCV infection. The predominant HCV genotype identifiedin the dialysis ward of tertiary care hospital was genotype 1a.

Seroprevalence of bovine leukemia virus and association with bovine infectious abortion in Creole breeds from tropical grazing herds in the Colombian Caribbean.

In the Caribbean region of Colombia, the concomitance of endemic infectious agents is a common problem, and coinfections are possible, increasing the complexity of cattle herds' sanitary, reproductive, and productive problems. This study aimed to estimate the seroprevalence of bovine leukemia virus and its association with bovine infectious abortion in grazing Creole breeds from tropical herds in the Colombian Caribbean. For the determination of bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV), bovine herpes virus-1 (BoHV-1), and Neospora Caninum (NC), the enzyme-linked immunosorbent assay technique was used. Matrix analysis was performed to represent multiple seroprevalence in the same cow. To explore the association between the seroprevalence of BLV and bovine infectious abortion agents, a multivariate logistic regression model was used. The seroprevalence was as follows: BLV 30.78%, BVDV 33.01%, BoHV-1 12.85%, and NC 8.96%. In the multivariate logistic regression model, seroprevalence of BVDV (OR 10.8; 95% CI: 7.5-15.6) and seroprevalence of BoHV-1 (OR 1.8; 95% CI: 1.1-3.0) were associated with the seroprevalence of BLV. Animals infected with BLV are more susceptible to coinfections with BVDV and BoHV-1. Implementing healthy measures against these two immunosuppressive infections could enhance the hygiene of numerous cattle herds. This study was designed as a retrospective cross-sectional study, which limits the ability to confirm that BLV is the primary infection. Further studies to confirm the primary infection of BLV with an active viral coinfection are necessary and the factors associated with these phenomena.

Exposure to Arboviruses in Cattle: Seroprevalence of Rift Valley Fever, Bluetongue, and Epizootic Hemorrhagic Disease Viruses and Risk Factors in Baringo County, Kenya.

Rift Valley fever virus (RVFV) causes disease outbreaks in livestock and humans; however, its inter-epidemic circulation is poorly understood, similar to other arboviruses affecting cattle such as bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV). Serum samples were collected in Baringo County, Kenya from 400 cattle, accompanied by a risk factor questionnaire. Serological tests were then conducted to determine the exposure of cattle to RVFV, BTV, and EHDV. RVFV, BTV, and EHDV IgG seroprevalence rates were 15.5%, 91.5%, and 91%, respectively. Seropositivity for RVFV, BTV, and EHDV was significantly higher in adult cattle, as well as in females for RVFV. Cattle with herd owners aged between 30-39 years were less likely to be seropositive for RVFV compared to those with owners over the age of 60 years. High seroprevalence of BTV and EHDV in cattle indicates significant exposure and the subclinical circulation of these viruses, presenting a risk of outbreaks to sheep and naïve cattle. Moreover, the detection of RVFV-seropositive young cattle born after the last reported outbreak suggests inter-epidemic circulation of the virus. Overall, monitoring these arboviruses in cattle is crucial in understanding their distribution and seroprevalence during inter-epidemic periods.

Trends in hepatitis C virus seroprevalence and associated risk factors among msm in Pakistan: insights from a community-based study

Pakistan bears a substantial burden of hepatitis C virus (HCV) infection, with the second-highest prevalence globally. This community-based cross-sectional study, conducted from January to December 2022 in Punjab, Pakistan, investigates the seroprevalence of HCV among the men who have sex with men (MSM) population. The study identifies demographic and behavioral risk factors associated with HCV infection within this population group. Among the 501 participants, the study found an HCV seroprevalence of 14.86%. The association between demographic characteristics and seroprevalence is assessed by calculating the percentage of positive cases, revealing notable associations with age, education level, and self-identified sexual orientation. Furthermore, the study identified several behavioral risk factors positively associated with HCV seroprevalence, including sharing personal items such as razors and toothbrushes, histories of surgery, blood transfusion, dental procedures, intravenous drug use, and therapeutic injection histories. These risk factors were identified through structured interviews, and the prevalence of HCV seropositivity among the exposed groups was calculated accordingly. Interestingly, a lower HCV positivity rate was observed among self-reported HIV-positive individuals, contradicting previous research. The findings underscore the need for comprehensive, targeted prevention strategies such as risk factor awareness campaigns and educational programs tailored for the MSM population in Pakistan. Further research is warranted to validate these findings and better understand the complex interplay of factors contributing to HCV seroprevalence in this high-risk population.

Seroprevalence and risk factors of sheep and goat pox virus in selected districts of Wolaita Zone, Southern Ethiopia.

Sheep and goat pox (SGP) virus infection is a highly fatal viral infection of small ruminants that causes major production losses in sheep and goats in Ethiopia while also limiting international trade. This study aimed to estimate the seroprevalence of SGP infection and assess related risk variables. A cross-sectional study was conducted from February to August 2023 on 384 serum samples taken from sheep and goats. A serum neutralization test was conducted to detect the presence of antibodies against the SGP virus in Wolaita Sodo Regional Laboratory. The overall seroprevalence rate of SGP was 4.95%. Factors such as sheep (8.26%), female sheep and goats (7.45%), older sheep and goats (8.33%), larger flock size of sheep and goats (10.47%), poorly conditioned sheep and goats (31.58%), sheep and goats with a tick on their skin (10.38%), and animals that had not been vaccinated (5.17%) were found to have higher seroprevalence. Furthermore, the seropositivity in sheep was five times greater than in goats (adjusted odds ratio [AOR], 4.73; 95% confidence interval [CI], 1.39-15.99). Additionally, large-sized flocks of sheep and goats were more likely to be seropositive to pox disease than small-sized flocks (AOR, 6.73; 95% CI, 1.58-28.67). Thus, the study revealed the prevalence of SGP in the Wolaita zone. Additional research should be conducted to estimate the extent of the disease at the regional level, and management measures should be implemented to reduce the economic losses associated with this condition.

Seroprevalence of human herpes viruses in France, 2018–2022: a multilevel regression and poststratification approach

Background Information related to herpes simplex virus 1 and 2 (HSV-1 and 2), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), and cytomegalovirus (CMV) seroprevalence in France is either lacking, incomplete, or outdated, despite their public health burden. Method We used routinely collected serological data between 2018 and 2022 to estimate HSV-1, HSV-2, VZV, EBV, and CMV seroprevalence in France. To account for demographic differences between our analytic samples and the French population and get estimates for sparsely sampled districts and age classes, we used a multilevel regression and poststratification approach combined with Bayesian model averaging via stacking weights. Results The observed seroprevalence (number of positive tests/number of tests) were 64.6% (93,294/144,424), 16.9% (24,316/144,159), 93.0% (141,419/152,084), 83.4% (63,199/75, 781), and 49.0% (23,276/47,525), respectively, for HSV-1, HSV-2, VZV, EBV, and CMV. Between 2018 and 2022, France had a model-based average (equal-tailed interval at 95%) expected seroprevalence equal to 61.1% (60.7,61.5), 14.5% (14.2,14.81), 89.5% (89.3,89.8), 85.6% (85.2,86.0), and 50.5% (49.3,51.7), respectively, for HSV-1, HSV-2, VZV, EBV, and CMV infections. We found an almost certain lower expected seroprevalence in Metropolitan France than in overseas territories for all viruses but VZV, for which it was almost certainly greater. The expected seroprevalences were likely greater among females for all viruses. Limitations Our results relied on the assumption that individuals were sampled at random conditionally to variables used to build the poststratification table. Implications The analysis highlights spatial and demographic patterns in seroprevalence that should be considered for designing tailored public health policies.

Seroprevalence of human immunodeficiency virus in African blood donors: a systematic review and meta-analysis

In developing countries, the safety of blood transfusions remains an important public health concern as it is associated with a higher risk of transfusion-transmissible infections (TTIs). In this study, we aimed to estimate the seroprevalence of HIV among blood donors in Africa and assess the temporal trends and regional differences within the continent through a systematic review and meta-analysis. Seven electronic databases (PubMed, Web of Science, Cochrane, Scopus, HINARI, Global Index Medicus and Clinical. gov) were searched for relevant studies for our research. We included all primary studies that estimated the seroprevalence of HIV among blood donors in Africa with an age population from 16 to 65 years old, without language restrictions, from inception up to March 1st 2024. The pooled seroprevalence was estimated through the DerSimonian-Laird random effects model. The temporal trends and regional differences were assessed through subgroup and meta-regression analysis. We obtained 122 studies that met our inclusion criteria, comprising 7,814,996 blood donors tested for HIV. Sixty-six percent of the studies were from Western and Eastern Africa. The pooled seroprevalence of HIV among blood donors in Africa was 2.66% (95% CI: 2.17-3.20%; I2=99.80%, p<0.01). The highest prevalence was observed in the Central African region, 3.28% (95% CI: 2.57%-4.06%), followed by the Eastern 3.21% (95% CI: 2.12%-4.52%), and the Western 2.66% (95% CI: 1.93%-3.49%) regions. Lower prevalences were observed in the Northern region, 0.57% (95% CI: 0.0%-2.10%), followed by the Southern African region with 0.45% (95% CI: 0.16%-0.86%). We observed a temporal decreased trend of HIV prevalence. The prevalence of HIV infection among African blood donors remains high and is not homogeneous across the continent. Efficient measures to strengthen HIV testing and prevent HIV transmission through blood transfusion are needed in Africa. Systematic review protocol registration: PROSPERO CRD42023395616. This article was supported by National Funds through FCT - Fundação para a Ciência e a Tecnologia,I.P., within CINTESIS, R&D Unit (reference UIDP/4255/2020).

Seroprevalence of Zika virus in pregnant women in Brazil: a cohort study in the macroregion of Dourados - Mato Grosso do Sul

Seroprevalence of Zika virus in pregnant women in Brazil: a cohort study in the macroregion of Dourados - Mato Grosso do Sul

West Nile Virus Seroprevalence in Wild Birds and Equines in Madrid Province, Spain.

West Nile virus (WNV) is a re-emerging flavivirus, primarily circulating among avian hosts and mosquito vectors, causing periodic outbreaks in humans and horses, often leading to neuroinvasive disease and mortality. Spain has reported several outbreaks, most notably in 2020 with seventy-seven human cases and eight fatalities. WNV has been serologically detected in horses in the Community of Madrid, but to our knowledge, it has never been reported from wild birds in this region. To estimate the seroprevalence of WNV in wild birds and horses in the Community of Madrid, 159 wild birds at a wildlife rescue center and 25 privately owned equines were sampled. Serum from thirteen birds (8.2%) and one equine (4.0%) tested positive with a WNV competitive enzyme-linked immunosorbent assay (cELISA) designed for WNV antibody detection but sensitive to cross-reacting antibodies to other flaviviruses. Virus-neutralization test (VNT) confirmed WNV antibodies in four bird samples (2.5%), and antibodies to undetermined flavivirus in four additional samples. One equine sample (4.0%) tested positive for WNV by VNT, although this horse previously resided in a WN-endemic area. ELISA-positive birds included both migratory and resident species, juveniles and adults. Two seropositive juvenile birds suggest local flavivirus transmission within the Community of Madrid, while WNV seropositive adult birds may have been infected outside Madrid. The potential circulation of flaviviruses, including WNV, in birds in the Madrid Community raises concerns, although further surveillance of mosquitoes, wild birds, and horses in Madrid is necessary to establish the extent of transmission and the principal species involved.

Hepatitis E virus seroprevalence in patients with human immunodeficiency virus: A single-center study in Japan

Hepatitis E virus (HEV) is a pathogen that causes hepatitis. There are few reports of HEV seroprevalence among people with human immunodeficiency virus (PWH) in Japan. This study aimed to determine the HEV seroprevalence among PWH at our hospital. Anti-HEV IgG was tested for using enzyme immunoassays and immunoblot assays. Clinical information was obtained from medical records and additional patient questionnaires. Sixty-eight PWH were included in this study. Four patients (5.9 %) showed HEV IgG seropositivity with both methods, while one patient (1.5 %) was seropositive using only the immunoblot assay, and three patients (4.4 %) were seropositive using only the enzyme immunoassay. There was a significant difference in age between anti-HEV IgG-seropositive and -negative individuals (median, 57.5 and 48.0 years, respectively; p = 0.012). There were no significant differences in the other clinical characteristics. Our results revealed that age is a risk factor for HEV infection among PWH.

Dengue Virus and Zika Virus Seroprevalence in the South Pacific Populations of the Cook Islands and Vanuatu

Arboviral diseases are serious threats to global health with increasing prevalence and potentially severe complications. Significant arthropod-borne viruses are the dengue viruses (DENV 1-4), the Zika virus (ZIKV), and the chikungunya virus (CHIKV). Among the areas most affected is the South Pacific Region (SPR). Here, arboviruses not only cause a high local burden of disease, but the region has also proven to contribute to their global spread. Outpatient serum samples collected between 08/2016 and 04/2017 on three islands of the island states of Vanuatu and the Cook Islands were tested for anti-DENV- and anti-ZIKV-specific antibodies (IgG) using enzyme-linked immunosorbent assays (ELISA). ELISA test results showed 89% of all test sera from the Cook Islands and 85% of the Vanuatu samples to be positive for anti-DENV-specific antibodies. Anti-ZIKV antibodies were identified in 66% and 52%, respectively, of the test populations. Statistically significant differences in standardized immunity levels were found only at the intranational level. Our results show that in both the Cook Islands and Vanuatu, residents were exposed to significant Flavivirus transmission. Compared to other seroprevalence studies, the marked difference between ZIKV immunity levels and previously published CHIKV seroprevalence rates in our study populations is surprising. We propose the timing of ZIKV and CHIKV emergence in relation to recurrent DENV outbreaks and the impact of seasonality as explanatory external factors for this observation. Our data add to the knowledge of arboviral epidemics in the SPR and contribute to a better understanding of virus spread, including external conditions with potential influence on outbreak dynamics. These data may support preventive and rapid response measures in the affected areas, travel-related risk assessment, and infection identification in locals and returning travelers.