Nicoletta Vonesch

Prevalence and incidence of antibodies to Borrelia burgdorferi and to tick-borne encephalitis virus in agricultural and forestry workers from Tuscany, Italy.

The ticks Ixodes persulcatus and Ixodes ricinus are the main vectors of both Borrelia burgdorferi sensu lato and tick-borne encephalitis (TBE) virus in Eurasia. Borrelia burgdorferi is the cause of Lyme borreliosis, and TBE is a biphasic meningoencephalitis induced by an arbovirus belonging to the flavivirus family. The principal aims of the current investigation were (i) to determine the frequency of serological evidence of Borrelia burgdorferi sensu lato and TBE infections in healthy agricultural and forestry workers, (ii) to determine the incidence of seroconversion for antibodies against Borrelia burgdorferi sensu lato and TBE virus in Tuscan workers during a 1-year survey; and (iii) to assess the occupational risk for agricultural and forestry activities in a defined area (Tuscany, Italy). A total of 412 blood samples were taken from agricultural and forestry workers, and information on age, duration of employment, and history of tick bites was collected in a questionnaire to establish the risk factors for the diseases. Three hundred sixty-five blood donors from the same region served as controls. To estimate the rate of seroconversion, 176 of the agricultural and forestry workers were tested 1 year later. IgG and IgM antibodies against Borrelia burgdorferi sensu lato and TBE virus were detected in serum by an enzyme-linked immunosorbent assay and confirmed by Western blot analysis for Borrelia burgdorferi and by a test for inhibition of hemagglutination for TBE. Antibodies against Borrelia burgdorferi were more frequent among the workers than in the control group (7.8% vs. 4.9% in the IgG-IgM enzyme-linked immunosorbent assay and 7.03% vs. 3.56% in the confirmatory test). No seropositivity was observed for TBE virus. Eighteen of 176 subjects who underwent a second blood test developed specific antibodies against Borrelia burgdorferi within 1 year.

Serosurvey against H5 and H7 avian influenza viruses in Italian poultry workers.

SUMMARY. Highly pathogenic (HP) and low pathogenic (LP) avian influenza viruses (AIVs) belonging to H5 and H7 subtypes have been found to be associated with human infection as the result of direct transmission from infected poultry. Human infections by AIVs can cause mild or subclinical disease, and serosurveys are believed to represent an important tool to identify risk of zoonotic transmission. Therefore, we sought to examine Italian poultry workers exposed during LPAI and HPAI outbreaks with the aim of assessing serologic evidence of infection with H5 and H7 AIVs. From December 2008 to June 2010 serum samples were collected from 188 poultry workers and 379 nonexposed controls in Northern Italy. The hemagglutination inhibition (HI) assay using horse red blood cells (RBCs) and a microneutralization (MN)–enzyme-linked immunosorbent assay test were used to analyze human sera for antibodies against the following H5 and H7 LPAI viruses: A/Dk/It/4445/07(H5N2); A/Ty/It/2369/09(H5N7); A/Ty/It/218-193/10; A/Ck/It/3775/99(H7N1); A/Ty/It/214845/03(H7N3); and A/Dk/It/332145/09(H7N3). Since previous studies identified low antibody titer to AIVs in people exposed to infected poultry, a cutoff titer of ≥1∶10 was chosen for both serologic assays. Only HI-positive results confirmed by MN assay were considered positive for presence of specific antibodies. The Fisher exact test was used to analyze differences in seroprevalence between poultry workers and control groups, with the significance level set at P < 0.05. MN results showed a proportion of H7-seropositive poultry workers (6/188, i.e., 3.2%), significantly higher than that of controls (0/379), whereas no MN-positive result was obtained against three H5 LPAI subtypes recently identified in Italy. In conclusion, the survey indicated that assessing seroprevalence can be an important tool in risk assessment and health surveillance of poultry workers.

Evidence of cross-reactive immunity to 2009 pandemic influenza A virus in workers seropositive to swine H1N1 influenza viruses circulating in Italy.

Background Pigs play a key epidemiologic role in the ecology of influenza A viruses (IAVs) emerging from animal hosts and transmitted to humans. Between 2008 and 2010, we investigated the health risk of occupational exposure to swine influenza viruses (SIVs) in Italy, during the emergence and spread of the 2009 H1N1 pandemic (H1N1pdm) virus. Methodology/Principal Findings Serum samples from 123 swine workers (SWs) and 379 control subjects (Cs), not exposed to pig herds, were tested by haemagglutination inhibition (HI) assay against selected SIVs belonging to H1N1 (swH1N1), H1N2 (swH1N2) and H3N2 (swH3N2) subtypes circulating in the study area. Potential cross-reactivity between swine and human IAVs was evaluated by testing sera against recent, pandemic and seasonal, human influenza viruses (H1N1 and H3N2 antigenic subtypes). Samples tested against swH1N1 and H1N1pdm viruses were categorized into sera collected before (n. 84 SWs; n. 234 Cs) and after (n. 39 SWs; n. 145 Cs) the pandemic peak. HI-antibody titers ≥10 were considered positive. In both pre-pandemic and post-pandemic peak subperiods, SWs showed significantly higher swH1N1 seroprevalences when compared with Cs (52.4% vs. 4.7% and 59% vs. 9.7%, respectively). Comparable HI results were obtained against H1N1pdm antigen (58.3% vs. 7.7% and 59% vs. 31.7%, respectively). No differences were found between HI seroreactivity detected in SWs and Cs against swH1N2 (33.3% vs. 40.4%) and swH3N2 (51.2 vs. 55.4%) viruses. These findings indicate the occurrence of swH1N1 transmission from pigs to Italian SWs. Conclusion/Significance A significant increase of H1N1pdm seroprevalences occurred in the post-pandemic peak subperiod in the Cs (p<0.001) whereas SWs showed no differences between the two subperiods, suggesting a possible occurrence of cross-protective immunity related to previous swH1N1 infections. These data underline the importance of risk assessment and occupational health surveillance activities aimed at early detection and control of SIVs with pandemic potential in humans.

Risk of acquiring tick-borne infections in forestry workers from Lazio, Italy

The seroprevalence of antibodies to Borrelia burgdorferi and tick-borne encephalitis (TBE) virus was evaluated in a group of forestry rangers in the Lazio region of Italy. One hundred and forty-five forestry rangers and 282 blood donors were examined by two-tiered serological tests for B. burgdorferi and TBE virus. Information on occupation, residence, tick bites, outdoor leisure activities and other risk factors was obtained. The prevalence of IgG/IgM antibodies to B. burgdorferi showed no statistical difference between the two groups, but there was a higher occurrence of IgM antibodies. There were significant differences between indoor and outdoor, urban and rural workplaces among the 145 exposed workers (χ2 test: p < 0.001), and a higher risk for outdoor rural than urban tasks was detected among the ten Western blot-tested forestry rangers positive to B. burgdorferi (χ2 test: p < 0.1). No seropositivity was observed for the TBE virus. Forestry rangers from the Lazio region did not have a higher risk of Borrelia infection than the blood donors, though an increase in the risk for outdoor tasks in a rural environment was observed.

Occupational risk associated with Toscana virus infection in Tuscany, Italy

BACKGROUND Sandfly fever virus serotype Toscana is endemic in Mediterranean countries and is a widespread public health problem as it may be associated with acute neurological diseases such as aseptic meningitis. AIM To assess whether Toscana virus infection is associated with occupational exposure. METHODS During the summer of 2001, a total of 678 blood samples were taken from healthy subjects residing in Tuscany (349 agricultural and forestry workers and 329 control subjects living in the same areas). Information on age, type of job and lifestyle was collected in a questionnaire, and sera were analysed using enzyme-linked immunosorbent assay for Toscana virus-specific antibodies. RESULTS Seropositivity to antibodies to Toscana virus was 30% in the control group and 23% in the agricultural and forestry workers (P<0.05). Questionnaire responses suggested that, although the agricultural and forestry workers had a potentially greater continuous exposure to sandfly fever virus (outdoor activities, rural residence and at-risk lifestyle), these risk factors did not add significant information about greater susceptibility to disease. CONCLUSION Our findings indicate a need for better understanding of the best preventive measures to avoid the risk related to sandfly bites, especially for people who live or work in areas at risk.

Screening for tuberculosis among homeless shelter staff.

The prevalence of tuberculosis (TB) among homeless shelter staff was assessed using the tuberculin skin test (TST) and the Quantiferon TB-Gold in tube interferon-γ release assay (QFT-TB). Investigation of 51 participants for whom both QFT-TB and TST results were available showed 47.1% and 43.1% positivity, respectively, with excellent (92%) concordance between the 2 tests. The high risk for acquiring occupational TB necessitates the development of TB surveillance protocols for homeless shelter staff in Italy.

Seroprevalence survey of arboviruses in workers from Tuscany, Italy

BACKGROUND Arthropod-borne viruses (Arbovirus) play an important role among emerging and re-emerging infectious diseases and in the spreading of infections in new geographic areas. Although some arboviral infections may be asymptomatic or mild flu-like illnesses, many occur as severe forms of meningitis and meningoencephalitis. OBJECTIVES To assess whether arboviral infections may be associated with occupational risk, in a population of agricultural and forestry workers potentially at high risk for arthropods bite and sting. METHODS A seroprevalence survey for arboviruses belonging to the genera Flaviviruses (West Nile, Tick-borne encephalitis and Usutu viruses) and Phlebovirus (Toscana virus) was carried out in Grosseto province (Tuscany, Italy). One hundred and one serum samples of occupationally exposed workers and 100 serum samples of not exposed workers were analyzed using commercial and home-made serological assays. Serological data were obtained in 2012 and analyzed according to demographic characteristics, recollection of insect-bites, and time spent in outdoor activities. RESULTS A total seropositivity of 10% (21/201) was observed for Toscana virus. No difference in seroprevalence for Toscana virus was observed among the exposed (10/101) versus the not exposed (11/100) workers. No seropositivity for West Nile, Usutu and Tick-borne encephalitis viruses was detected. CONCLUSIONS Although circulation of Toscana virus is recognized in the study area, our results did not reveal a higher risk for workers exposed to arthropods bite and sting. Health surveillance programs remain useful to monitor the potential emergence of arboviruses.

Laboratory and occupational medicine: considerations and perspectives regarding biological risk

SummaryBackgroundWe considered some aspects of laboratory medicine and occupational medicine, with special reference to biological risk, looking for those elements that could be essential parts of both medical fields.MethodsWe evaluated the national and international literature on biological risk with particular attention to the main features of laboratory and occupational medicine, including errors sources, quality, concept of risk, guidelines and risk reduction.ResultsRisk management, training, communication, involvement and participation of different professionals are characteristics of both disciplines, and it is important to promote a risk culture in order to mitigate biological risk.ConclusionsThe study of biological risk should include risk assessment and management, through a multidisciplinary approach aimed at eliminating and/or reducing risks. The spread of new methodologies has led to improvement in the study of biological risk and better integration between laboratory and occupational medicine.RiassuntoPremesseSono stati considerati alcuni aspetti riguardanti la medicina di laboratorio e occupazionale con particolare riferimento al rischio biologico, mettendo in evidenza alcuni elementi che possono essere parti essenziali di entrambi i campi della medicina.MetodiIn tale lavoro è stata studiata la letteratura nazionale e internazionale sul rischio biologico, con particolare attenzione alle principali caratteristiche della medicina di laboratorio e occupazionale: fonti di errori, qualità, concetto di rischio, linee guida, riduzione del rischio.RisultatiLa gestione del rischio, la formazione, la comunicazione, il coinvolgimento e la partecipazione di diverse figure professionali sono caratteristiche principali di entrambe le discipline ed è importante promuovere una cultura del rischio al fine di mitigare il rischio biologico.ConclusioniLo studio del rischio biologico dovrebbe includere la valutazione e la gestione del rischio, attraverso un approccio multidisciplinare volto a eliminare e/o ridurre il rischio. La diffusione di nuove metodologie ha consentito di migliorare lo studio del rischio biologico e una migliore integrazione tra medicina di laboratorio e medicina del lavoro.