Preventing the risk of prion transmission via neurosurgical instruments: a case report

U posljednjih 10 godina Hrvatskom zavodu za javno zdravstvo prijavljeno je 15 bolesnika oboljelih od Creutzfeldt-Jakobove bolesti (CJB). Tijekom lipnja 2012. godine u Općoj bolnici Varaždin (OBV) preminuo je 58-godišnji bolesnik premješten s Klinike za neurologiju KBC Zagreb pod sumnjom na sporadični oblik CJB. Nakon obdukcije bolesnika, koja je provedena u našoj ustanovi, dijagnoza CJB potvrđena je patohistološkom analizom mozga u Kliničkom institutu za neurologiju Medicinskog fakulteta u Beču. Povjerenstvo za sprječavanje i suzbijanje bolničkih infekcija OBV izradilo je upute o mjerama i načinu postupanja s prostorima, opremom i instrumentima koji su bili potencijalno kontaminirani prionima. Obzirom da se radilo o bolesniku koji je 2,5 mjeseca prije postavljene dijagnoze bio neurokirurški operiran u našoj ustanovi, a upotrijebljeni neurokirurški instrumenti nisu bili tretirani po principu dekontaminacije priona, postavljeno je pitanje potencijalnog prijenosa priona kontaminiranim instrumentima na 29 bolesnika koji su naknadno neurokirurški operirani. Analizom neurokirurškog zahvata utvrdili smo da su neurokirurški instrumenti bili u kontaktu s kožom, potkožjem, fascijama mišića, kostima i intervertebralnom hrskavicom bolesnika, ali ne i s tvrdom moždanom ovojnicom, niti je za vrijeme operacije bilo likvoreje. Zaključili smo da tijekom neurokirurškog zahvata nije došlo do kontakta instrumenata s tkivima visokog i srednjeg rizika za prijenos priona te je rutinski postupak s neurokirurškim instrumentima (rutinsko čišćenje i sterilizacija) bio dostatan za sprječavanje prijenosa priona, sukladno smjernicama britanske i kanadske grupe za kontrolu CJB. Naknadnim praćenjem nije registriran niti jedan slučaj sekundarne CJB u 29 bolesnika operiranih nakon ovog bolesnika u našoj bolnici.In the last 10 years there have been 15 cases of Creutzfeldt-Jakob disease (CJD) reported to the Croatian Institute of Public Health/Department of Epidemiology. In June 2012, a 58-year-old patient that had been relocated from the Department of Neurology of the University Hospital Centre Zagreb to General Hospital Varaždin, died from a suspected sporadic form of Creutzfeldt-Jakob disease. After autopsy was performed in our hospital, CJD was confirmed by histopathological analysis of the brain in the Clinical Institute of Neurology/Medical University of Vienna. The Hospital Infection Control Committee drafted guidelines for infection control measures regarding work areas, equipment and instruments that were potentially contaminated with prions. Since the patient had undergone a neurosurgical operation in our institution 2.5 months prior to CJD diagnosis, and the neurosurgical instruments used during this procedure were not processed according to the prion decontamination principles, a question was raised regarding a potential prion transmission via contaminated instruments to the 29 patients who subsequently underwent neurosurgical operation. By analyzing the neurosurgical procedure that the patient underwent, we established that neurosurgical instruments were in contact with the patient\u27s skin, subcutaneous tissue, fascia muscle, bones and intervertebral cartilage and not with the dura mater and that there was no cerebrospinal fluid drainage during surgery either. Therefore, we concluded that during neurosurgery the instruments did not come into contact with tissues of higher or medium risk for transmission of prions and that routine procedure for cleaning and sterilization of neurosurgical instruments was sufficient for preventing prion transmission, which is in accordance with the British and Canadian CJD infection control guidelines. Subsequent follow-up recorded not a single case of secondary CJD among the 29 patients who underwent surgery after the infected patient in our hospital

Knowledge, Attitudes, Psychosocial Perspectives and Applied Epidemiology in the Control of Head Lice (pediculosis capitis) in Croatian Preschool Children: A Qualitative Study on Childcare Professionals and Health Coordinators

This study aimed to concurrently determine the perceived knowledge, attitudes and perspectives of childcare professionals working in kindergartens towards pediculosis capitis, a common ectoparasitic disease also known as head lice, as well as gain insights into procedures and control measures that are implemented in an outbreak setting. We used a qualitative approach with a problem-centered, semi-structured and three-part interview technique conducted in selected kindergartens of Varaždin and Međimurje counties of the Republic of Croatia. Based on a purposive (deliberate) sampling method, the study included both childcare professionals and on-site health coordinators aged between 21 and 56 years of age. Five main themes were put forth as a result of the conducted thematic analysis: prevention and control measures for managing head lice, information and knowledge, social issues, psychological issues and disease perception. Each of these themes also had specific emerging categories based on participants’ responses. Even though all respondents confirmed that the disease is continuously monitored only a few of them mentioned that a scalp examination was an inherent part of disease surveillance within the kindergarten community. Moreover, we found that information on pediculosis capitis is available to both parents and childcare professionals, but with a questionable uptake. Additionally, the majority of the respondents reported that parents tend to hide the infestation in their children due to shame and/or to avoid social stigma, and thus often fail to inform kindergarten teachers and health coordinators about the problem. In conclusion, our findings have implications for further practice and the introduction of tailored public health measures for the most vulnerable populations, most notably kindergarten children

Slower Waning of Anti-SARS-CoV-2 IgG Levels Six Months after the Booster Dose Compared to Primary Vaccination

Anti-SARS-CoV-2 IgG titer decreases rapidly after primovaccination, leading to a mandatory booster vaccination. We analysed anti-SARS-CoV-2 Spike RBD IgG levels (positive ≥ 50 AU/mL) in 405 healthcare workers (3010 sera) who received a booster dose (BD) 9 months after two-dose BNT162b2 primovaccination. Median antibody titer at the time of BD (582.6 AU/mL) was 1.7-fold and 16.4-fold lower than the peak titer after the first (961.5 AU/mL) and the second vaccine dose (SVD) (10,232.6 AU/mL), respectively. One month after vaccination, IgG titer increased 40.6-fold after BD compared with a 10.8-fold increase after primovaccination. Three months after vaccination, post-booster antibodies decreased significantly slower (2.2-fold) than after primovaccination (3.3-fold). At six months, antibodies decreased slower after BD (4.5-fold; median 5556.0 AU/mL) than after primovaccination (9.6-fold; median 1038.5 AU/mL). Antibody titers before and one month after BD correlated weakly (r = 0.30) compared with a strong correlation (r = 0.65) between the corresponding post-primovaccination titers. Pre-vaccination COVID-19 had no effect on IgG levels after BD compared with a positive effect after primovaccination. Despite high post-booster IgG levels, 22.5% of participants contracted mild COVID-19. The trend of IgG decline indicates the need for further revaccination, but the vaccine type should be defined according to viral mutations

Decline of Anti-SARS-CoV-2 IgG Antibody Levels 6 Months after Complete BNT162b2 Vaccination in Healthcare Workers to Levels Observed Following the First Vaccine Dose

Research on post-vaccination antibody dynamics has become pivotal in estimating COVID-19 vaccine efficacy. We studied anti-SARS-CoV-2 Spike RBD IgG levels in 587 healthcare workers (2038 sera) who completed BNT162b2 vaccination. Average antibody titer 3 weeks after the first dose in COVID-19-naïve participants (median 873.5 AU/mL) was 18-fold higher than the test threshold, with a significant increase 1 month (median 9927.2 AU/mL) and an exponential decrease 3 (median 2976.7 AU/mL) and 6 (median 966.0 AU/mL) months after complete vaccination. Participants with a history of COVID-19 prior to vaccination showed significantly higher antibody levels, particularly after the first dose (median 14,280.2 AU/mL), with a slight decline 1 month (median 12,700.0 AU/mL) and an exponential decline in antibody titers 3 (median 4831.0 AU/mL) and 6 (median 1465.2 AU/mL) months after vaccination. Antibody levels of COVID-19-naïve subjects after the first dose were moderately correlated with age (r = −0.4). Multivariate analysis showed a strong independent correlation between IgG levels 6 months after vaccination and both IgG titers after the first dose and 1 month after vaccination (R2 = 0.709). Regardless of pre-vaccination COVID-19 history, IgG levels 6 months after vaccination were comparable to antibody levels reached by COVID-19-naïve participants after the first vaccine dose

Diagnostic significance of immunoglobulin G avidity in symptomatic and asymptomatic West Nile virus infection

INTRODUCTION: West Nile virus (WNV) immunoglobulin M (IgM) antibodies have been shown to persist for up to 500 days in certain patients. To evaluate the usefulness of immunoglobulin G (IgG) avidity assessment in the diagnosis of WNV infection, we analyzed 54 WNV IgM- and/or IgG-positive serum samples from 39 patients with neuroinvasive disease and 15 asymptomatic cases tested during a seroprevalence investigation. ----- METHODS: Serological tests (WNV IgM/IgG antibody detection, IgG avidity) were performed using commercially available enzyme-linked immunosorbent assays. ----- RESULTS: WNV IgM antibodies were detected in 47 (87%) samples. Acute/recent WNV infection was confirmed based on low/borderline avidity index (AI) in 44 IgM-positive samples (93.6%). In three IgM-positive samples (6.4%), high IgG AIs were detected, thus indicating persisting IgM antibodies from previous infections. All IgM-negative samples showed high AIs. Patients with WNV neuroinvasive disease tested within 30 days showed low AIs. In six patients tested 34-50 days after disease onset, AI was borderline (42%-60%), suggesting earlier WNV IgG maturation. Samples with the highest IgM values were associated with the lowest AIs (Spearman's rho coefficient -0.767, p < 0.001). ----- CONCLUSIONS: Our results indicate that IgG avidity differentiates current/recent WNV infection from persistent IgM seropositivity from the previous WNV transmission season both in patients with WNV neuroinvasive disease and in asymptomatic persons. A strong negative correlation between IgM antibody levels and AI indicates that in cases with very high IgM levels, determination of IgG avidity may not be necessary. As many patients showed rapid avidity maturation, low IgG avidity is indicative of WNV infection within the previous month

Diagnostic significance of immunoglobulin G avidity in symptomatic and asymptomatic West Nile virus infection

Abstract INTRODUCTION West Nile virus (WNV) immunoglobulin M (IgM) antibodies have been shown to persist for up to 500 days in certain patients. To evaluate the usefulness of immunoglobulin G (IgG) avidity assessment in the diagnosis of WNV infection, we analyzed 54 WNV IgM- and/or IgG-positive serum samples from 39 patients with neuroinvasive disease and 15 asymptomatic cases tested during a seroprevalence investigation. METHODS Serological tests (WNV IgM/IgG antibody detection, IgG avidity) were performed using commercially available enzyme-linked immunosorbent assays. RESULTS WNV IgM antibodies were detected in 47 (87%) samples. Acute/recent WNV infection was confirmed based on low/borderline avidity index (AI) in 44 IgM-positive samples (93.6%). In three IgM-positive samples (6.4%), high IgG AIs were detected, thus indicating persisting IgM antibodies from previous infections. All IgM-negative samples showed high AIs. Patients with WNV neuroinvasive disease tested within 30 days showed low AIs. In six patients tested 34-50 days after disease onset, AI was borderline (42%-60%), suggesting earlier WNV IgG maturation. Samples with the highest IgM values were associated with the lowest AIs (Spearman's rho coefficient -0.767, p < 0.001). CONCLUSIONS Our results indicate that IgG avidity differentiates current/recent WNV infection from persistent IgM seropositivity from the previous WNV transmission season both in patients with WNV neuroinvasive disease and in asymptomatic persons. A strong negative correlation between IgM antibody levels and AI indicates that in cases with very high IgM levels, determination of IgG avidity may not be necessary. As many patients showed rapid avidity maturation, low IgG avidity is indicative of WNV infection within the previous month