Autochthonous Dengue Fever in 2 Patients, Rome, Italy.

Since August 2023, outbreaks of dengue virus (DENV) infection have occurred in Italy. We report 2 autochthonous case-patients and their extended follow-up. Despite persistent DENV detected in blood by PCR, results for antigenomic DENV RNA were negative after day 5, suggesting that a 5-day isolation period is adequate to avoid secondary cases.

Profiling the acute phase antibody response against mpox virus in patients infected during the 2022 outbreak.

Information on the immune response during the mpox virus (MPXV) infection is still scarce or limited to past studies when cross-reactive immunity from smallpox vaccination was predominant. Here, we describe the short-term kinetics of the antibody response in patients with acute MPXV infection during the 2022 multicountry outbreak. A total of 64 samples from 18 MPXV-positive patients were longitudinally collected from the day of symptom onset (DSO) up to 20 days after and tested for anti-MPXV immunoglobulin G (IgG), IgM, IgA, and neutralizing antibodies (nAb) using the whole-live virus isolated in May 2022. IgG, IgM, and IgA were detected as early as 4 DSO (median time of seroconversion 7.5 DSO for IgG, 8 DSO for IgM and IgA). Anti-MPXV nAb were detectable in samples collected as early as 1 week after symptoms, with stable levels up to 20 DSO. After 2 weeks, IgG and nAb reached high titers. No significant differences were observed regardless of status of smallpox vaccination, human immunodeficiency virus positivity, or disease severity. Significant lower levels of IgM and IgG were observed in the patients treated with antivirals. These results contribute to extending the knowledge of the MPXV infection and the antibody response in a population with no historic smallpox vaccination.

Comparison of SARS-CoV-2 Detection in Nasopharyngeal Swab and Saliva Samples from Patients Infected with Omicron Variant.

To compare the detection of the SARS-CoV-2 Omicron variant in nasopharyngeal-swab (NPS) and oral saliva samples. 255 samples were obtained from 85 Omicron-infected patients. SARS-CoV-2 load was measured in the NPS and saliva samples by using Simplexa™ COVID-19 direct and Alinity m SARS-CoV-2 AMP assays. Results obtained with the two diagnostic platforms showed very good inter-assay concordance (91.4 and 82.4% for saliva and NPS samples, respectively) and a significant correlation among cycle threshold (Ct) values. Both platforms revealed a highly significant correlation among Ct obtained in the two matrices. Although the median Ct value was lower in NPS than in saliva samples, the Ct drop was comparable in size for both types of samples after 7 days of antiviral treatment of the Omicron-infected patients. Our result demonstrates that the detection of the SARS-CoV-2 Omicron variant is not influenced by the type of sample used for PCR analysis, and that saliva can be used as an alternative specimen for detection and follow-up of Omicron-infected patients.

Infectious Toscana Virus in Seminal Fluid of Young Man Returning from Elba Island, Italy.

We report detecting infectious Toscana virus in the seminal fluid of a 25-year-old man from Italy returning from Elba Island. The presence of infectious virus in human semen adds Toscana virus to the long list of viruses detected in this genital fluid and indicates a potential for sexual transmission.

Predicting the protective humoral response to a SARS-CoV-2 mRNA vaccine.

OBJECTIVES: Simple and standardized methods to establish correlates to vaccine-elicited SARS-CoV-2 protection are needed. METHODS: An observational study on antibody response to a mRNA vaccine (Comirnaty) was performed on health care workers (V, n=120). Recovered COVID-19 patients (N, n=94) were used for comparison. Antibody response was evaluated by a quantitative anti-receptor binding domain IgG (anti-RBD) commercial assay and by virus microneutralization test (MNT), in order to establish a threshold of anti-RBD binding antibody units (BAU) able to predict a robust (≥1:80) MNT titer. RESULTS: Significant correlation between BAU and MNT titers was found in both V and N, being stronger in V (rs=0.91 and 0.57 respectively, p<0.001); a higher incremental trend starting from MNT titer 1:80 was observed in the V group. The 99% probability of high MNT titer (≥1:80) was reached at 1,814 and 3,564 BAU/mL, and the area under the receiver operating characteristic (ROC) curve was 0.99 (CI: 0.99-1.00) and 0.78 (CI: 0.67-0.86) in V and N, respectively. CONCLUSIONS: A threshold of 2,000 BAU/mL is highly predictive of strong MNT response in vaccinated individuals and may represent a good surrogate marker of protective response. It remains to be established whether the present results can be extended to BAU titers obtained with other assays.

Lumipulse G SARS-CoV-2 Ag assay evaluation using clinical samples from different testing groups.

OBJECTIVES: Compared to RT-PCR, lower performance of antigen detection assays, including the Lumipulse G SARS-CoV-2 Ag assay, may depend on specific testing scenarios. METHODS: We tested 594 nasopharyngeal swab samples from individuals with COVID-19 (RT-PCR cycle threshold [Ct] values ≤ 40) or non-COVID-19 (Ct values >40) diagnoses. RT-PCR positive samples were assigned to diagnostic, screening, or monitoring groups of testing. RESULTS: With a limit of detection of 1.2 × 104 SARS-CoV-2 RNA copies/mL, Lumipulse showed positive percent agreement (PPA) of 79.9% (155/194) and negative percent agreement of 99.3% (397/400), whereas PPAs were 100% for samples with Ct values of <18 or 18-<25 and 92.5% for samples with Ct values of 25-<30. By three groups, Lumipulse showed PPA of 87.0% (60/69), 81.1% (43/53), or 72.2% (52/72), respectively, whereas PPA was 100% for samples with Ct values of <18 or 18-<25, and was 94.4, 80.0, or 100% for samples with Ct values of 25-<30, respectively. Additional testing of RT-PCR positive samples for SARS-CoV-2 subgenomic RNA showed that, by three groups, PPA was 63.8% (44/69), 62.3% (33/53), or 33.3% (24/72), respectively. PPAs dropped to 55.6, 20.0, or 41.7% for samples with Ct values of 25-<30, respectively. All 101 samples with a subgenomic RNA positive result had a Lumipulse assay's antigen positive result, whereas only 54 (58.1%) of remaining 93 samples had a Lumipulse assay's antigen positive result. CONCLUSIONS: Lumipulse assay was highly sensitive in samples with low RT-PCR Ct values, implying repeated testing to reduce consequences of false-negative results.

SARS-CoV-2 Phylogenetic Analysis, Lazio Region, Italy, February-March 2020.

We report phylogenetic and mutational analysis of severe acute respiratory syndrome coronavirus 2 virus strains from the Lazio region of Italy and provide information about the dynamics of virus spread. Data suggest effective containment of clade V strains, but subsequently, multiple waves of clade G strains were circulating widely in Europe.

Differential diagnosis of illness in patients under investigation for the novel coronavirus (SARS-CoV-2), Italy, February 2020.

A novel coronavirus (SARS-CoV-2) has been identified as the causative pathogen of an ongoing outbreak of respiratory disease, now named COVID-19. Most cases and sustained transmission occurred in China, but travel-associated cases have been reported in other countries, including Europe and Italy. Since the symptoms are similar to other respiratory infections, differential diagnosis in travellers arriving from countries with wide-spread COVID-19 must include other more common infections such as influenza and other respiratory tract diseases.

Coronavirus disease (COVID-19) in a paucisymptomatic patient: epidemiological and clinical challenge in settings with limited community transmission, Italy, February 2020.

Data concerning the transmission of the novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) in paucisymptomatic patients are lacking. We report an Italian paucisymptomatic case of coronavirus disease 2019 with multiple biological samples positive for SARS-CoV-2. This case was detected using the World Health Organization protocol on cases and contact investigation. Current discharge criteria and the impact of extra-pulmonary SARS-CoV-2 samples are discussed.

Detection of Viral RNA in Tissues following Plasma Clearance from an Ebola Virus Infected Patient.

An unprecedented Ebola virus (EBOV) epidemic occurred in 2013-2016 in West Africa. Over this time the epidemic exponentially grew and moved to Europe and North America, with several imported cases and many Health Care Workers (HCW) infected. Better understanding of EBOV infection patterns in different body compartments is mandatory to develop new countermeasures, as well as to fully comprehend the pathways of human-to-human transmission. We have longitudinally explored the persistence of EBOV-specific negative sense genomic RNA (neg-RNA) and the presence of positive sense RNA (pos-RNA), including both replication intermediate (antigenomic-RNA) and messenger RNA (mRNA) molecules, in the upper and lower respiratory tract, as compared to plasma, in a HCW infected with EBOV in Sierra Leone, who was hospitalized in the high isolation facility of the National Institute for Infectious Diseases "Lazzaro Spallanzani" (INMI), Rome, Italy. We observed persistence of pos-RNA and neg-RNAs in longitudinally collected specimens of the lower respiratory tract, even after viral clearance from plasma, suggesting possible local replication. The purpose of the present study is to enhance the knowledge on the biological features of EBOV that can contribute to the human-to-human transmissibility and to develop effective intervention strategies. However, further investigation is needed in order to better understand the clinical meaning of viral replication and shedding in the respiratory tract.

Expanding Usutu virus circulation in Italy: detection in the Lazio region, central Italy, 2017 to 2018.

Blood donation screening for West Nile virus (WNV) was mandatory in the Lazio region in 2017 and 2018 (June-November) according to the national surveillance plan. In these years, all five donations reactive in WNV nucleic acid amplification tests harboured instead Usutu virus (USUV). Clade 'Europe 2' was identified in four blood donations and a 2018 mosquito pool. The cocirculation of WNV and USUV in Lazio warrants increased laboratory support and awareness of possible virus misidentification.

Molecular Characterization of Autochthonous Chikungunya Cluster in Latium Region, Italy.

We report partial molecular characterization of isolates from an autochthonous chikungunya virus cluster in Latium Region. E1 sequences from 3 patients differ substantially from sequences from the 2007 outbreak in Italy and lack the A226V substitution associated with increased viral fitness in the Aedes albopictus mosquito vector.

ZIKV Infection Induces an Inflammatory Response but Fails to Activate Types I, II, and III IFN Response in Human PBMC.

The recent epidemic in the Americas caused by Zika virus (ZIKV), Asian lineage, spurred the research towards a better understanding of how ZIKV infection affects the host immune response. The aim of this study was to evaluate the effects of Asian and East African ZIKV strain infection on the induction of IFN and proinflammatory and Th2 cytokines in human PBMC. We reported a slight modulation of type II IFN in PBMC exposed to Asian strain, but not to African strain, and a complete lack of type I and III IFN induction by both strains, suggesting the ability of ZIKV to evade the IFN system not only inhibiting the antiviral IFN response but also IFN production. Moreover, we highlighted a polyfunctional immune activation only in PBMC exposed to Asian strain, due to the induction of an inflammatory profile (IL-6, IL-8) and of a Th9 (IL-9) response. Overall, our data show a different ability of the ZIKV Asian strain, with respect to the African strain, to activate host immune response that may have pathogenetic implications for virus spread in vivo, including mother-to-child transmission and induction of severe fetal complications, as birth defects and neurological disorders.

Prolonged detection of dengue virus RNA in the semen of a man returning from Thailand to Italy, January 2018.

This study reports the presence of dengue virus RNA in longitudinally collected semen samples of a previously healthy Caucasian man, returning to Italy from Thailand with primary dengue fever, up to 37 days post-symptom onset, when viraemia and viruria were undetectable. This finding, coupled with the evidence of dengue virus negative-strand RNA, an indirect marker of ongoing viral replication, in the cellular fraction of semen, indicates a need to further investigate possible sexual transmission.

Persistence of ZIKV-RNA in the cellular fraction of semen is accompanied by a surrogate-marker of viral replication. Diagnostic implications for sexual transmission.

As asymptomatic infections represent 80% of ZIKV-infected individuals, sexual transmission is a rising concern. Recent studies highlighted a preferential association of ZIKV with the cellular fraction (CF) of different specimen types. Our aim was to evaluate the presence of ZIKV-RNA in different body fluids, focusing on semen specimens to assess the ZIKV-RNA content in either the unfractionated sample, its CF or seminal plasma (SP). In addition, to establish if the presence of ZIKV genome was associated with active virus replication, we measured the levels of negative-strand ZIKV-RNA. ZIKV total-RNA was detected in blood, urine and unfractionated semen, and neg-RNA in semen CF and SP samples longitudinally collected from two ZIKV-positive men followed at the National Institute for Infectious Diseases "L. Spallanzani", Italy. In both patients, ZIKV total-RNA was detected in CF with ct values always lower than in the corresponding unfractionated samples, and was observed even in the CF from negative unfractionated semen samples. In Patient 2, neg-RNA was also detected in CF, suggesting ongoing viral replication. Our results demonstrate higher clinical sensitivity of CF as compared to whole semen testing, emphasizing the need to extend ZIKV-RNA testing to CF, to rule out virus presence and the possible risk of sexual transmission.

Measles Cases during Ebola Outbreak, West Africa, 2013-2106.

The recent Ebola outbreak in West Africa caused breakdowns in public health systems, which might have caused outbreaks of vaccine-preventable diseases. We tested 80 patients admitted to an Ebola treatment center in Freetown, Sierra Leone, for measles. These patients were negative for Ebola virus. Measles virus IgM was detected in 13 (16%) of the patients.

Emerging Zika Virus Infection: A Rapidly Evolving Situation.

Zika virus is a mosquito-borne flavivirus, firstly identified in Uganda and responsible for sporadic human cases in Africa and Asia until recently, when large outbreak occurred in Pacific Ocean and the Americas. Since the main vectors during its spread outside of Africa have been Ae. albopictus and Ae. aegypti mosquitoes, which are widely distributed all over the world, there is urgent need for a coordinated response for prevention and spread of ZIKV epidemics.Despite clinical manifestation of Zika virus infection are usually mild and self limiting, there are reports suggesting, during the recent epidemic, an association of ZIKV infection with severe consequences, including fetal/newborn microcephaly, due to vertical in utero transmission, autoimmune-neurological presentations including cranial nerve dysfunction, and Guillain-Barré Syndrome in adults. The primary mode of transmission of Zika virus between humans is through the bite of an infected female mosquito of the Aedes genus, but also sexual and blood transfusion transmission may occur. Moreover, a case of non-sexual spread from one person to another has been described, indicating that we still have more to learn about Zika transmission.Biological basis for pathogenetic effects are under investigation. Laboratory diagnosis is challenging since, so far, there are no "gold standard" diagnostic tools, and the low and short viremia in the acute phase, and together with the high cross-reactivity among the members of flavivirus genus are the most challenging aspects to be overcome.

An outbreak of chickenpox in an asylum seeker centre in Italy: outbreak investigation and validity of reported chickenpox history, December 2015-May 2016.

An outbreak of chickenpox occurred between December 2015 and May 2016 among asylum seekers in a reception centre in Latium, Italy. We describe the epidemiological and laboratory investigations, control measures and validity of reported history of chickenpox infection. Serological screening of all residents and incoming asylum seekers was performed, followed by vaccine offer to all susceptible individuals without contraindication. Forty-six cases were found and 41 were associated with the outbreak. No complications, hospitalisations or deaths occurred. Serological testing was performed in 1,278 individuals and 169 were found to be susceptible, with a seroprevalence of 86.8%. A questionnaire was administered to 336 individuals consecutively attending the CARA health post to collect their serological result. The sensitivity, specificity and the positive and negative predictive value (PPV and NPV) of the reported history of chickenpox were 45.0%, 76.1%, 88.3% and 25.6%, respectively. We observed an increasing trend for the PPV and decreasing trend for the NPV with increasing age. Our report confirms that, in the asylum seeker population, chickenpox history is not the optimal method to identify susceptible individuals. Our experience supports the need for additional prevention and control measures and highlights the importance of national and local surveillance systems for reception centres.

Measles in Italy: Co-circulation of B3 variants during 2014.

In 2013, the majority of the WHO/EUR countries reported an annual incidence of >1 case per one million population indicating that the elimination target is far from being met. Thus, there is the urgent need to uncover and analyze chains of measles virus (MV) transmission with the objective to identify vulnerable groups and avoid possible routes of introduction of MV variants in the European population. The analysis of molecular epidemiology of MV B3 strains identified in 2014 has shown that four different variants co-circulated in Italy, including the strain that caused a cruise-line ship outbreak at the beginning of the year.

Three cases of Zika virus imported in Italy: need for a clinical awareness and evidence-based knowledge.

BACKGROUND: Since early 2015, a large epidemic of Zika Virus (ZIKV) is spreading across South and Central America. An association between congenital neurological malformations (mainly microcephaly), other neurological manifestations such as Guillain-Barrè Syndrome, and ZIKV infection is suspected. CASE PRESENTATION: Three confirmed cases of ZIKV in travelers returning from Brazil between May 2015 and January 2016 are described. All patients had mild symptoms with no neurological complications. CONCLUSIONS: An increasing awareness among clinicians about this emerging disease is advisable, both for the need to provide correct additional information to the patients and to travelers, with a special focus on pregnant women, and for the presence of the competent vector in Southern Europe.