Surveillance of SARS-CoV-2 antibodies of patients in the local affected area during Wuhan lockdown

Background Serosurveillance is crucial in estimating the range of SARS-CoV-2 infections, predicting the possibility of another wave, and deciding on a vaccination strategy. To understand the herd immunity after the COVID-19 pandemic, the seroprevalence was measured in 3062 individuals with or without COVID-19 from the clinic. Methods The levels of SARS-CoV-2 antibody IgM and IgG were measured by the immuno-colloidal gold method. A fusion fragment of nucleocapsid and spike protein was detected by a qualitative test kit with sensitivity (89%) and specificity (98%). Results The seroprevalence rate for IgM and IgG in all outpatients was 2.81% and 7.51%, respectively. The sex-related prevalence rate of IgG was significantly higher (P < 0.05) in women than men. The highest positive rate of IgM was observed in individuals < 20 years of age (3.57%), while the highest seroprevalence for IgG was observed in persons > 60 years of age (8.61%). Positive rates of IgM and IgG in the convalescent patients were 31.82% and 77.27%, respectively, which was significantly higher than individuals with suspected syndromes or individuals without any clinical signs (P < 0.01). Seroprevalence for IgG in medical staff was markedly higher than those in residents. No significant difference of seroprevalence was found among patients with different comorbidities (P > 0.05). Conclusions The low positive rate of the SARS-CoV-2 IgM and nucleic acid (NA) test indicated that the SARS-CoV-2 outbreak is subsiding after 3 months, and the possibility of reintroduction of the virus from an unidentified natural reservoir is low. Seroprevalence provides information for humoral immunity and vaccine in the future.

Neospora caninum Infection in Cattle in the Province of Kohgiluyeh and Boyer Ahmad, Southwest of Iran: Seroprevalence and Molecular Assessment

Introduction. Among the protozoa of veterinary importance, Neospora caninum is responsible for large economic and productive losses in cattle herds. Dogs are being considered the definitive hosts of the parasite. Neospora caninum has gained considerable attention through its role in the etiology of bovine abortion. The current study aimed at assessing the status of Neospora infection in cattle in Boyer-Ahmad County in Kohgiluyeh and Boyer-Ahmad province, southwest of Iran. Methods. In this cross-sectional study, 150 cattle blood samples were collected and samples were screened for N. caninum antibodies using a modified direct agglutination test (MAT). For the same samples, 130 buffy coats were collected and tested, by PCR, for the presence of N. caninum DNA, targeting the Nc-5 gene. Results. Anti-N. caninum antibodies were detected in the sera of 49 out of 150 cattle which is corresponding to a seroprevalence rate of 32.7%. Neospora DNA was detected in buffy coats of 26 out of 127 (20.47%) cattle. Even though Neospora infection was more common in females and in five-year-old cattle by serology and molecular methods, yet there was no statistically significant difference between age, sex, and Neospora infection in both molecular and serological methods ( p > 0.05 ). Conclusion. Findings of the current study indicate a high rate of N. caninum infection in cattle of Boyer-Ahmad region in the southwest of Iran. This issue should be further investigated and the prevention and control of this parasite in livestock, due to the high financial burden of this parasite in the livestock industry, should be considered.

Seroprevalence and Associated Risk Factors of Toxoplasma Gondii Among Pregnant Women in Southwest Iran

Background: Acute Toxoplasma gondii infection during pregnancy period can cause congenital toxoplasmosis. The aim of this study was to assess the seroprevalence rate of immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies against T. gondii infection during pregnancy and the associated risk factors in southwest Iran. Methods: This study was performed on 88 pregnant women from October to December 2019 in Khorramshahr County, Khuzestan province, Iran. Anti-T. gondii IgG and IgM antibodies were tested through enzyme-linked immunosorbent assay (ELISA) method. Results: Following serological assays, 38.63% (34/88) and 2.27% (2/88) serum samples were positive for IgG and IgM antibodies, respectively. Also, a statistically significant association was observed between IgG seroprevalence and drinking of unpurified water (P = 0.015). Conclusions: The serological evidence revealed that pregnant women of southwest Iran had moderate exposure to T. gondii parasite. Since the risk of acquiring acute toxoplasmosis in pregnant women is clinically important, we highly recommend regular screening tests for T. gondii infection during pregnancy period.

Seroprevalence of SARS-CoV-2 Infection in the Colombo Municipality Region, Sri Lanka

Background: As the Municipality Council area in Colombo (CMC) experienced the highest number of cases until the end of January 2021, in Sri Lanka, we carried out a serosurvey prior to initiation of the vaccination program to understand the extent of the SARS-CoV-2 outbreak.Methods: SARS-CoV-2 seropositivity was determined in 2,547 individuals between the ages of 10–86 years, by the Wantai total antibody ELISA. We also compared seroprevalence using the haemagglutination test (HAT) to evaluate its usefulness in carrying out serosurveys.Results: The overall seropositivity rate was 24.46%, while seropositivity by HAT was 18.90%. Although The SARS-CoV-2 infection detection rates by PCR were highest in the population between the ages of 20–60 years of age, there was no statistically significant difference in the seropositivity rates in different age groups. For instance, although the seropositivity rate was highest in the 10–20 age group (34.03%), the PCR positivity rate was 9.80%. Differences in the PCR positivity rates and seropositivity rates were also seen in 60–70-year-olds (8.90 vs. 30.4%) and in individuals &gt;70 years (4.10 vs. 1.20%). The seropositivity rate of the females was 29.70% (290/976), which was significantly higher (p &lt; 0.002) than in males 21.2% (333/1,571).Conclusions: A high seroprevalence rate (24.5%) was seen in all age groups in the CMC suggesting that a high level of transmission was seen during this time. The higher PCR positivity rates between the ages of 20–60 are likely to be due to increased testing carried out in the working population. Therefore, the PCR positivity rates, appear to underestimate the true extent of the outbreak and the age groups which were infected.

1383. Universal Strongyloides Screening in a Heart Transplant Program in South Carolina: Just How Endemic Is It?

Background Strongyloides stercoralis is endemic in sub-Saharan Africa, Southeast Asia, Latin America, and the southeastern United States, particularly Appalachia, where Strongyloides seroprevalence approaches 2%. SC is considered a state in which Strongyloides is endemic, however the degree of endemnicity is not known. Here we define the epidemiology of chronic strongyloidiasis in our state, through data obtained via universal screening of heart transplant candidates at our center. Methods This single center retrospective study was performed at a 700 bed academic medical center that is the only comprehensive transplant center in SC. All adult patients who underwent heart transplant evaluation 1/1/2019 - 12/31/2020 were included. Routine pre-transplant evaluation by Transplant Infectious Diseases (TxID) was implemented in the heart transplant program in 2015 and universal screening with Strongyloides IgG began in late 2018. We assessed demographics, risk factors for exposure to Strongyloides, treatment, and outcomes for seropositive subjects. Results During the study period, 218 patients underwent heart transplant evaluation. Adherence to universal screening was 96.8% (211/218). 187 subjects (88.6%) had negative screening results (≤ 0.9 IV) and 24 subjects (11.4%) had equivocal or positive screening results (≥ 1.0 IV). Demographics and risk factors for the 24 equivocal/positive subjects are presented in Table 1. 15 equivocal/positive subjects (66.7%) received ivermectin and 9 (33.3%) did not. The majority of untreated patients were declined for transplant (8/9) and did not have a TxID evaluation (6/9). One untreated patient was waitlisted for transplant and has received ivermectin since being identified in this study. There were no episodes of hyperinfection or disseminated infection in the cohort. Table 1. Demographics and risk factors for subjects with equivocal or positive Strongyloides IgG Conclusion Universal screening of adult heart transplant candidates at SC’s only transplant center detected a Strongyloides seroprevalence rate of 11.4%. The majority of subjects with equivocal/positive Strongyloides IgG were born in the US and did not have other known risk factors (residence in the Appalachian region of SC, military service, overseas travel). These data suggest a high level of endemnicity of strongyloidiasis in SC. Disclosures All Authors: No reported disclosures

West Nile virus seroprevalence and associated risk factors among horses in Egypt

Determination of the seroprevalence and risk factors that are associated with West Nile virus (WNV) in horses is essential for adoption of effective prevention strategies. Our objective in this study, therefore, was to determine the seroprevalence and to identify the risk factors associated with WNV infection in the most densely horse-populated governorates in Egypt. A cross-sectional study was conducted in 2018 on 930 horses, which were distributed over five governorates in the Nile delta of Egypt. The horses, which were randomly selected, were serologically tested through use of an ID screen West Nile competition enzyme-linked immunosorbent assay (ELISA) to detect anti-WNV immunoglobulin G (IgG) and plaque reduction neutralization tests (PRNT; gold standard) to confirm the seropositive status of animals and to avoid cross reaction with other flavi-viruses. Four variables (geographical location, breed, sex and age) were considered in the risk analysis. Univariable and stepwise forward multivariable logistic regression methods were used for risk-factor analysis. The odds ratio (OR) was used as an approximate measure of relative risk. A total of 156 (16.8%; 95% confidence interval (CI) 14.4–19.2; P < 0.001) serum samples were found to be serologically positive for WNV. The highest seroprevalence rate was detected in horses of age ≥ 15 years (68.1%; 95% CI 49.8–72.4), stallions (26.4%; 95% CI 22.7–30.4), and those of mixed breed (21.5%; 95% CI 17.7–27.5). Horses older than 15 years were found to be at increased risk of WNV infection with OR = 4.3 (95% CI 3.0–6.2, P < 0.001) compared with horses aged under 2.5 years. Also, when all the risk factors were considered, stallions were more likely than mares to be WNV seropositive (OR = 2.4, 95% CI 1.6–3.7, P < 0.001), and of the breeds, mixed-breed (OR = 1.9, 95% CI 1.2–2.8, P = 0.005) and Arabian horses (OR = 1.9, 95% CI 1.2–2.8, P = 0.005) were more likely to be seropositive. Geographical location seemed to have no impact on the seroprevalence of exposure to WNV among these horses. Due to these findings, we strongly recommend intensive surveillance and implementation of effective control and prevention strategies against WNV, especially in stallion, mixed-breed horses with ages ≥ 15 years.

Seroepidemiological Studies on Japanese Encephalitis: A Systematic Review

Background Japanese encephalitis (JE) is one of the major mosquito-borne infectious diseases in the Western Pacific region, accounting for 20-30% of mortality cases. The JE virus (JEV) seroprevalence fluctuations indicate that continuous research is important for prevention and control activities. By mapping JEV seroprevalence by age stratification, the population profile for immunity and susceptibility can be identified to aid in vaccination programme planning. Thus, the aim of this study is to determine the trend of age-specific JEV seroprevalence. Method Systematic search was conducted on all studies conducted on JEV seroprevalence between the years 2010 until 2019. The two search engines used were PubMed and Web of Science. Eligible criteria were set and articles were screened according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. Three investigators cross-checked all articles assigned. Data were extracted into Excel sheet and results were tabulated in tables and graphs accordingly. Result Four studies from four countries (Taiwan, Sri Lanka, South Korea, India) met the eligibility criteria. The papers show an increasing trend of JEV seropositivity in all countries as their populations reach older age cohorts. Nonetheless, there were slight downtrend notches seen among young adults in Taiwan and India before increasing again after reaching more mature ages. South Korea has the highest seroprevalence rate (97.8% to 98.3%) among the compared countries; this is most likely because it was the earliest to introduce the JEV vaccine in 1967 which was later made mandatory in early 1980s, while India has the lowest seroprevalence rate (12.9% to 18.1%). Among the old-vaccination-naïve population, seropositivity is commonly derived from natural infection. Conclusion Decreases in reported JE cases are mainly due to immunisation. As JEV is expected to remain in nature and the zoonotic chains, the risk of infection will persist. Hence, it is important to apply JEV vaccination protocols in national immunisation programmes with priority given to those at the young childhood stages.

Seroprevalence and Risk Factors Associated with Canine Leishmaniasis in Egypt

Background: Canine leishmaniasis (CanL) is caused by Leishmania infantum (L. infantum) that is transmitted by sand fly vectors with dogs acting as the main reservoir. Methods: The present study aimed to determine the seroprevalence of CanL in dogs from Egypt and assessed the associated risk factors. The study was conducted from 2019 to 2020 in five governorates situated in Northern Egypt. Serum samples from 450 asymptomatic dogs were serologically examined by use of enzyme-linked immunosorbent assay (ELISA). Results: Overall, the seroprevalence rate of CanL was 21.3% and the highest rates were observed in Cairo and Giza governorates. The univariable analysis revealed that the seropositivity of CanL was strongly related to the dogs′ ages, length of hair, absence of veterinary care or application of insecticides, and the type of floor of their shelters. The risk factors that were found to be associated with CanL in exposed dogs were: age group 2–4 years old (OR = 12, 95% CI: 1.6–92.3); short hair (OR = 2.07, 95% CI: 1.2–3.6); absence of veterinary care (OR = 2.7, 95% CI: 1.3–5.8); no application of insecticides (OR = 3.09, 95% CI: 1.5–6.5) and their residence in a shelter with an earthen floor (OR = 1.42, 95% CI: 0.7–2.9). Conclusions: Based on the present results, CanL is present in Egyptian dogs and this increases the possibility of transmission by sand fly to humans with whom they have contact. Consequently, an efficient monitoring programme and effective control measures are important to reduce the risk of infection.

2019–2020 measles in the Republic of Guinea: epidemic features and herd immunity

Introduction. In connection with the Ebola epidemic in the West African countries, including the Republic of Guinea, a failure in implementing measles immunization program was noted. A proportion of measles seronegative subjects in 2017 was 52.4% of total examined individuals. In 2018, a high proportion of measles cases among children aged 1–5 years (61.6%) was identified. In order to stop the 2018 outbreak, the Supplemental Immunization Campaign was conducted in the Konakri and Nzerekore prefectures in the Republic of Guinea. The aim of this study was to examine the 2019–2020 measles epidemic situation and assess the measles population immunity in the Republic of Guinea. Materials and methods. Measles-specific antibodies were examined in 1697 blood serum samples collected from residents of different regions of the Republic of Guinea, aged from 7 months to 76 years, obtained in 2019–2020, and tested retrospectively. The ELISA test systems Anti-Measles Virus ELISA (IgM) Euroimmun and Anti-Measles Virus ELISA (IgG) Euroimmun (Germany) were used. The presence of serum IgM measles antibodies was considered as acute measles infection. Statistical analysis was performed using the software package Statistica 6.0. Results. Blood sera (n = 638) were tested for IgM-measles, and in 46.6% of cases the diagnosis was confirmed by laboratory tests. The biggest proportion of the total cases (61.6%) was found in children aged 1–4 years. The second most important age group was 5–9 years of age, the third is children under 1 year: 18.5% and 11.8% of the total number of patients, respectively. Measles infection was registered in vaccinated patients in 7.4% of the total number of laboratory-confirmed cases. 1059 subjects were examined for IgG measles antibody. The lowest seroprevalence rate was found among children under 4 years of age (47.8%). The highest (85.5%) was found among subjects of 40 years old and older. Conclusion. Measles in GR remains a poorly controlled infection. As in the previous years of observation (2017–2018), children under 5 years of age are the most vulnerable cohort of the population, despite the 2018 DI campaign conducted in a number of GR territories. More problems with the measles control in the Republic of Guinea are expected in the period from 2021, as along with the COVID-19 epidemic, Ebola is repeatedly registered in the country. The Republic of Guinea particularly requires assistance from the international community to implement the WHO measles elimination program on a global scale.

A Literature Review of Neospora caninum Infection in Humans

Background: Neosporosis is a parasitic disease caused by Neospora caninum. This parasite is an obligate intracellular coccidia similar to Toxoplasma gondii with a global distribution. With regard to the experimental studies, vertical transmission of the parasite in the monkey (non-human primates) has increased the concern about the zoonotic potential of this disease. The principal aim of the current research was to perform a mini-review on investigations regarding the Neospora infection in humans on a global scale for the first time. Methods: All peer-reviewed articles (published until April 2021) on the Neospora infection in humans were searched in English databases such as Google Scholar, ScienceDirect, Scopus, PubMed, and ProQuest. Results: Based on data in the available articles, the presence of antibodies against the Neospora infection was between 0 and 37.7% in people from different countries. The seroprevalence rate of this infection in HIV-positive individuals was higher (26.6% and 37.7%) compared to other cases. Finally, the genomic DNA of Neospora was detected up to 1% using molecular biology techniques. Conclusions: Overall, the detection of anti-Neospora antibodies in humans indicated that people have been exposed to the parasite. Comprehensive research studies are essential for clarifying the risk factors associated with the Neospora infection in humans. This report provides the baseline information for future researchers. Molecular investigations and genotypic works on N. caninum isolates are highly recommended as well.