MOSQUITO RESISTANCE TO INSECTICIDES IN BULGARIA

Mosquitoes are a group of blood-sucking insects that plays a major role in disease transmission in both humans and animals. They can pose a heavy nuisance, or serve as vectors of numerous viruses and parasites on most continents, including Europe. The strategy for successful control of the mosquito populations relies on the use of insecticides of five different categories: organochlorines, organophosphates, carbamates, pyrethroids, and biopesticides. The extensive use of the first four classes has resulted in the development of resistance originating in various mechanisms. The main ones are metabolic resistance and genetic resistance, manifested by point mutations in the insecticide targets, resulting in limited binding of neurotoxic substances. Much data is available on mosquito insecticide resistance in Bulgaria between 1948 and 1990, but only regarding organochlorines, organophosphates and carbamates. There is no data on pyrethroid resistance, which should raise an alarm for both public health authorities and private pest control companies since the only insecticides registered for professional mosquito control nowadays are pyrethroids. Therefore, there is an urgent need for the use of modern multidisciplinary approaches to study the resistance of native and invasive species of mosquitoes to insecticides, which should be a key contribution to elucidating their role in the circulation of pathogens of humans and animals and optimizing methods for controlling their populations

Single-dose cholera vaccine in response to an outbreak in Zambia

Producción CientíficaKilled oral cholera vaccines (OCVs) are part of the standard response package to a cholera outbreak, although the two-dose regimen of vaccines that has been prequalified by the World Health Organization (WHO) poses challenges to timely and efficient reactive vaccination campaigns.1 Recent data suggest that the first dose alone provides short-term protection, similar to that of two doses, which may largely dictate the effect of OCVs during epidemic

Global disparities in SARS-CoV-2 genomic surveillance

Genomic sequencing is essential to track the evolution and spread of SARS-CoV-2, optimize molecular tests, treatments, vaccines, and guide public health responses. To investigate the global SARS-CoV-2 genomic surveillance, we used sequences shared via GISAID to estimate the impact of sequencing intensity and turnaround times on variant detection in 189 countries. In the first two years of the pandemic, 78% of high-income countries sequenced >0.5% of their COVID-19 cases, while 42% of low- and middle-income countries reached that mark. Around 25% of the genomes from high income countries were submitted within 21 days, a pattern observed in 5% of the genomes from low- and middle-income countries. We found that sequencing around 0.5% of the cases, with a turnaround time <21 days, could provide a benchmark for SARS-CoV-2 genomic surveillance. Socioeconomic inequalities undermine the global pandemic preparedness, and efforts must be made to support low- and middle-income countries improve their local sequencing capacity

Echovirus 30 in Bulgaria during the European Upsurge of the Virus, 2017–2018

In 2018, an increase in echovirus 30 (E30) detections was reported in some European countries. To assess the circulation and phylogenetic relationships of E30 in Bulgaria, E30 samples identified at the National Reference Laboratory for Enteroviruses, National Centre of Infectious and Parasitic Diseases, Bulgaria (NRL for Enteroviruses) in 2017 and 2018 were subjected to sequencing and phylogenetic analysis. The present study revealed that sample positivity did not significantly increase in Bulgaria during the European upsurge. E30 was identified in six patients, two of whom were epidemiologically linked. The maximum-likelihood phylogenetic tree showed that sequences from five patients belonged to the G1 lineage (clades G1a and G1b). The sequence from one patient belonged to the G2 lineage and was grouped closer to sequences from the last E30 outbreak in Bulgaria in 2012. No recombination events were detected. The European E30 upsurge in 2018 was caused by two clades, and one of them was G1. The fact that the majority of the Bulgarian samples belonged to G1 indicated that the virus was present in the country but did not cause a local upsurge. Phylogenetic and epidemiological data indicated sporadic E30 cases and a possible shift towards G1 lineage in 2017 and 2018

Immunity to mumps virus in children population in Bulgaria

AbstractMumps is an acute, contagious, viral vaccine-preventable disease caused by mumps virus (MuV). The measles, mumps, rubella (MMR) vaccine that is used in many countries is considered highly effective with decreased MuV incidence, but suboptimal MuV long-term immunity. This study assessed the MuV seropositivity and antibody titre among vaccinated children in Bulgaria to provide evidence for a better understanding of MuV circulation and immunity in Bulgaria. The samples from 734 immunized children (369 females and 365 males) aged 1 to 16, divided into four age groups (≥1, 2–6, 7–11, and 12–16) were tested. Qualitative and quantitative indirect enzyme-linked immunosorbent assay (Anti-Mumps IgG ELISA, Euroimmun, Germany) was performed to determine the mumps IgG antibody levels in sera. Among all participants, protective MuV immunity was identified in 93%. MuV IgG antibody positivity ranged between 87% in the age group between 1 and 2 years and 96% in the age group 12–16 years, but no statistically significant difference was found among age groups. At the same time, there was a statistically significant difference (p = 0.01) between seropositivity in male and female participants, with male participants having an overall seropositivity of 90% and female 95%. Among the antibody-positive samples, the quantitative measurements of median anti-MuV IgG concentrations showed that titres decreased with increasing age. A slightly waning immunity following vaccination was observed, but positivity remained high among vaccinated children over the years. Similar studies show that maintaining high immunity is crucial to prevent mumps outbreaks

Bulgarian General Practitioners’ Communication Styles about Child Vaccinations, Mainly Focused on Parental Decision Making in the Context of a Mandatory Immunization Schedule

The communication practices of general practitioners in relation with vaccines have not been a topic of wide scientific interest. In this article, we outline them in the context of Bulgaria. A representative, cross-sectional, quantitative, face-to-face survey was conducted among 358 Bulgarian general practitioners in 2022 using simple random sampling. We conducted an exploratory factor analysis using questions about the role of the GPs, which measure models of communication. Based on the factor analysis, we distinguished four communication styles. They were called: active communicator, restrictive communicator, informing communicator, and strained communicator. One-way ANOVA and the T-test were carried out to explore the connections between factor scores (communication styles) and other variables. One of the most important results in the study was that the informing physician (emphasizing the choice of the parents) was the most common model in Bulgaria. This is somewhat contradictory, because of the mandatory status of most vaccines. We found connections between the communication styles and other variables—such as the type of settlement, having a hesitant parent in the practice, recommendations of non-mandatory vaccines, and experience with vaccine-preventable diseases. On the basis of the factor analysis and analysis of relationships with other variables, we reached the conclusion that in Bulgaria, hesitant parents are not sufficiently involved in active, effective communication about vaccines by GPs