Seroprevalence of Epstein-Barr virus and cytomegalovirus infections in Presidente Figueiredo, Amazonas, Brazil.

Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections affect around 95% of the world's population. In Brazil, there are few epidemiological reports related to EBV and CMV infection, especially in the western Amazon region. This study aimed to estimate the seroprevalence of EBV and CMV infection in individuals residents in Presidente Figueiredo, Amazonas, Brazil. Blood samples of 443 individuals were tested for the presence of anti-EBV and anti-CMV IgG antibodies through an enzyme-linked immunosorbent assay. EBV (95.9%; 95% CI: 0.94;0.98), CMV (96.8%; 95% CI: 0.95;0.98) and CMV/EBV (93%;95% CI: 0.91-0.95) coinfection were highly prevalent in the study population. Children (1 to 5 years) not attending school were less susceptible to EBV (OR 0.15; 95% CI: 0.05-0.52; p = 0.017) and CMV infections (OR 0.05; 95% CI: 0.02 - 0.17; p < 0.0001). Teenagers at high school showed increased susceptibility to CMV infection (OR 4.65; 95%CI: 1.43-15.08; p = .013) and EBV/CMV co-infection (OR 3.04; 95%CI: 1.44-6.45; p = 0.005). The seroprevalence of CMV and EBV infections were preeminent and tend to increase with age in the study population. Either attendance to a daycare facility or primary school before the age of 5 years may increase the susceptibility to EBV or CMV infection.

Prevalence and Recurrence Rates of Cytomegalovirus Infection Among Patients With Hematological Diseases in the Western Brazilian Amazon: A Cross-Sectional Study.

Cytomegalovirus (CMV) is a worldwide distributed pathogen that may cause serious complications in patients with hematological diseases. This study aimed to serologically characterize CMV infection in patients suffering from hematological diseases in Amazonas state, Brazil. Serum samples from 323 patients were tested for the presence of anti-CMV IgM or IgG antibodies using an enzyme-linked immunosorbent assay. Positive samples for IgM were submitted to the IgG avidity test to differentiate primary infection from recurrent infection. An epidemiological questionnaire was administered to collect the sociodemographic information of the study population. The overall prevalence of CMV infection verified in this study was 91.3%. The highest rates were found in patients suffering from platelet disorders (94.5%), anemia (93.3%), or leukemia (91%). The study population was predominantly composed of individuals with low socioeconomic status. Blood transfusions were more common in patients with anemia or leukemia, but this variable was not correlated with the seropositivity for CMV infection. Measurement of IgG avidity in patients positive for anti-CMV IgM demonstrated a recurrent infection rate of 5.2% (17/323). Over 80% of recurrent infections occurred in patients with acute lymphocytic leukemia (ALL) or anemia. Our findings indicated that CMV infection is highly prevalent in patients from the western Brazilian Amazon who have hematological diseases. The prevalence observed progressively rose with increasing age, whereas anemia or ALL figured as risk factors for the recurrence of CMV infection.

Increased vulnerability to SARS-CoV-2 infection among indigenous people living in the urban area of Manaus.

The COVID-19 pandemic threatens indigenous peoples living in suburban areas of large Brazilian cities and has thus far intensified their pre-existing socio-economic inequalities. We evaluated the epidemiological situation of SARS-CoV-2 infection among residents of the biggest urban multiethnic indigenous community of the Amazonas state, Brazil. Blood samples of 280 indigenous people living in the surrounding area of Manaus were tested for the presence of anti-SARS-CoV-2 IgA or IgG antibodies. The risk factors and sociodemographic information were assessed through an epidemiological questionnaire. We found a total positivity rate of 64.64% (95% CI 59.01-70.28) for SARS-CoV-2 infection. IgA and IgG were detected in 55.71% (95% CI 49.89-61.54) and 60.71% (95% CI 54.98-66.45) of the individuals, respectively. Over 80% of positive individuals were positive for both IgA and IgG.No significant difference in positivity rates between genders or age groups was observed. Moreover, the age group ≥ 60 years old showed the highest antibody ratios (IgA mean ratio = 3.080 ± 1.623; IgG mean ratio = 4.221 ± 1.832), while the age groups 13-19 and 20-29 showed the lowest IgA (mean ratio = 2.268 ± 0.919) and IgG ratios (mean ratio = 2.207 ± 1.246), respectively. Individuals leaving the home more frequently were at higher risk of infection (Odds ratio (OD) 2.61; 95% CI 1.00-1.49; p = 0.048). Five or more individuals per household increased fivefold the risk of virus transmission (OR 2.56; 95% CI 1.09-6.01; p = 0.019). The disproportionate dissemination of SARS-CoV-2 infection observed among the study population might be driven by typical cultural behavior and socioeconomic inequalities. Despite the pandemic threat, this population is not being targeted by public policies and appears to be chronically invisible to the Brazilian authorities.

Epidemiological and Liver Biomarkers Profile of Epstein-Barr Virus Infection and Its Coinfection with Cytomegalovirus in Patients with Hematological Diseases.

Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are viruses globally distributed that have been associated with the development and prognosis of many pathologies, including hematological diseases. This study aimed to characterize the epidemiological profile of EBV infection and the infection-correlated hepatic manifestations in patients with hematological diseases of the northern Brazilian state of Amazonas. A total of 228 patients were serologically tested for the presence of anti-EBV and anti-CMV IgG antibodies through an enzyme-linked immunosorbent assay. The coinfection with CMV, sociodemographic and laboratory records of all patients were also assessed. The overall prevalence observed among the study population for EBV infection and EBV/CMV coinfection was 85.09% (95% CI: 0.80-0.90) and 78.51% (95% CI: 0.73-0.84), respectively. The age group 31-40 years old were more susceptible to EBV/CMV coinfection (95% CI: 1.59-93.41, p = 0.011), while young people aged 1-10 years old were less affected for both EBV infection (CI 95%; 0.66-0.91, p = 0.001) and EBV/CMV coinfection (95% CI: 0.52-0.81, p < 0.0001). High serum levels of the liver biomarker ferritin were associated with EBV infection (95% CI: 1.03-1.54, p = 0.031) and EBV/CMV coinfection (95% CI: 1.02-1.70, p = 0.038). Our findings indicated that the elevated prevalence of EBV infection is not associated with the hematological diseases or transfusion rates, but with the socioeconomic status of the study population. Also, this study suggests that the EBV infection and its coinfection with CMV are related to the increase of serum ferritin levels.

Cytomegalovirus and Epstein-Barr Infections: Prevalence and Impact on Patients with Hematological Diseases.

Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infections are widely distributed throughout the world. EBV is linked to various hematological and autoimmune disorders whereas CMV might play important role in the progression of chronic hematological diseases, such as hemoglobinopathies, lymphomas, myelomas, hemophilia, and aplastic and sickle cell anemia. Both viruses produce a viral homolog of human interleukin-10 that can cause general suppression of immune response, increasing susceptibility to other infections. These viruses can remain latent in the host cells and be reactivated when the host immune system is compromised. Studies showing the impact of CMV and EBV infections on hematological disorders are scarce and unclear in the context of coinfection. This review intends to present the biology, prevalence, and impact of CMV and EBV infections in patients with hematological diseases.

Gene expression changes in the salivary glands of Anopheles coluzzii elicited by Plasmodium berghei infection.

BACKGROUND: Malaria is a devastating infectious disease caused by Plasmodium parasites transmitted through the bites of infected Anopheles mosquitoes. Salivary glands are the only mosquito tissue invaded by Plasmodium sporozoites, being a key stage for the effective parasite transmission, making the study of Anopheles sialome highly relevant. METHODS: RNA-sequencing was used to compare differential gene expression in salivary glands of uninfected and Plasmodium berghei-infected Anopheles coluzzii mosquitoes. RNA-seq results were validated by quantitative RT-PCR. The transmembrane glucose transporter gene AGAP007752 was selected for functional analysis by RNA interference. The effect of gene silencing on infection level was evaluated. The putative function and tertiary structure of the protein was assessed. RESULTS: RNA-seq data showed that 2588 genes were differentially expressed in mosquitoes salivary glands in response to P. berghei infection, being 1578 upregulated and 1010 downregulated. Metabolism, Immunity, Replication/Transcription/Translation, Proteolysis and Transport were the mosquito gene functional classes more affected by parasite infection. Endopeptidase coding genes were the most abundant within the differentially expressed genes in infected salivary glands (P < 0.001). Based on its putative function and expression level, the transmembrane glucose transporter gene, AGAP007752, was selected for functional analysis by RNA interference. The results demonstrated that the number of sporozoites was 44.3% lower in mosquitoes fed on infected mice after AGAPP007752 gene knockdown when compared to control (P < 0.01). CONCLUSIONS: Our hypothesis is that the protein encoded by the gene AGAPP007752 may play a role on An. coluzzii salivary glands infection by Plasmodium parasite, working as a sporozoite receptor and/or promoting a favorable environment for the capacity of sporozoites.

Mosquito Akirin as a potential antigen for malaria control.

BACKGROUND: The control of vector-borne diseases is important to improve human and animal health worldwide. Malaria is one of the world's deadliest diseases and is caused by protozoan parasites of the genus Plasmodium, which are transmitted by Anopheles spp. mosquitoes. Recent evidences using Subolesin (SUB) and Akirin (AKR) vaccines showed a reduction in the survival and/or fertility of blood-sucking ectoparasite vectors and the infection with vector-borne pathogens. These experiments suggested the possibility of using AKR for malaria control. METHODS: The role of AKR on Plasmodium berghei infection and on the fitness and reproduction of the main malaria vector, Anopheles gambiae was characterized by evaluating the effect of akr gene knockdown or vaccination with recombinant mosquito AKR on parasite infection levels, fertility and mortality of female mosquitoes. RESULTS: Gene knockdown by RNA interference in mosquitoes suggested a role for akr in mosquito survival and fertility. Vaccination with recombinant Aedes albopictus AKR reduced parasite infection in mosquitoes fed on immunized mice when compared to controls. CONCLUSIONS: These results showed that recombinant AKR could be used to develop vaccines for malaria control. If effective, AKR-based vaccines could be used to immunize wildlife reservoir hosts and/or humans to reduce the risk of pathogen transmission. However, these vaccines need to be evaluated under field conditions to characterize their effect on vector populations and pathogen infection and transmission.