Neuroinvasive phlebovirus infection in Greece: a case report

Current Arboviral Threats and Their Potential Vectors in Thailand

Arthropod-borne viral diseases (arboviruses) are a public-health concern in many regions of the world, including Thailand. This review describes the potential vectors and important human and/or veterinary arboviruses in Thailand. The medically important arboviruses affect humans, while veterinary arboviruses affect livestock and the economy. The main vectors described are mosquitoes, but other arthropods have been reported. Important mosquito-borne arboviruses are transmitted mainly by members of the genus Aedes (e.g., dengue, chikungunya, and Zika virus) and Culex (e.g., Japanese encephalitis, Tembusu and West Nile virus). While mosquitoes are important vectors, arboviruses are transmitted via other vectors, such as sand flies, ticks, cimicids (Family Cimicidae) and Culicoides. Veterinary arboviruses are reported in this review, e.g., duck Tembusu virus (DTMUV), Kaeng Khoi virus (KKV), and African horse sickness virus (AHSV). During arbovirus outbreaks, to target control interventions appropriately, it is critical to identify the vector(s) involved and their ecology. Knowledge of the prevalence of these viruses, and the potential for viral infections to co-circulate in mosquitoes, is also important for outbreak prediction.

Of phlebotomines (sandflies) and viruses: a comprehensive perspective on a complex situation

Old World sandfly-borne phleboviruses are classified into three serological complexes: Sandfly fever Sicilian, Sandfly fever Naples and Salehabad. Human pathogens (febrile illness ['sandfly fever'], neuroinvasive infections) belong to the two first complexes. The increasing number of newly discovered sandfly-borne phleboviruses raises concerns about their medical and veterinary importance. They occupy a wide geographic area from Mediterranean basin to North Africa and the Middle East to the central Asia. At least nine species of sandflies can transmit these viruses. Recent results suggest that sandfly vectors are not as specific for viruses as initially believed. Recent seroprevalence studies demonstrate that humans and domestic animals are heavily exposed. Specific molecular diagnostic methods must be developed and implemented in clinical microbiology laboratories.

Preparing clinicians for (re-)emerging arbovirus infectious diseases in Europe

BACKGROUND

Arthropod-borne virus (Arbovirus) infections are considered an emerging threat for Europe, with an increase in cases in recent decades. The increase in global travel and trade has contributed to the introduction of vectors and viruses into new geographical areas. Tropical arboviruses such as dengue and chikungunya have re-emerged causing local, sporadic outbreaks ignited by travel-imported cases. The recent Zika virus outbreak in the Americas highlighted a need to strengthen preparedness for (re-)emerging arbovirus infections globally.

AIMS

To strengthen preparedness for the early identification of (re-)emerging arbovirus outbreaks in Europe and highlight areas for research.

SOURCES

An evidence review of published and grey literature together with consultations with European arbovirus experts.

CONTENT

This paper presents an overview of endemic and travel-imported arboviruses of clinical significance in Europe. The overview includes syndromic presentation, risk factors for infection and risk of transmission as well as an update on treatments and vaccinations and surveillance notifications and reporting. The paper also presents predictive modelled risks of further geographical expansion of vectors and viruses.

IMPLICATIONS

There are a range of arboviruses of clinical significance to Europe. There has been an increase in notifications of endemic and travel-imported arbovirus cases in recent years and an increased geographical range of vectors and viruses. The heterogeneity in surveillance reporting indicates a risk for the early identification of (re-)emerging outbreaks. The data presented show a need to strengthen preparedness for (re-)emerging arbovirus infections and a need for research into neglected arboviruses, risks of non-vector transmission and effective therapeutics and vaccinations.

Phlebovirus infections in Greece

Sandfly fever viruses are endemic in the Mediterranean region causing to humans asymptomatic or mild infections to severe neurological syndromes. In order to investigate the epidemiology of phlebovirus infections in Greece, samples from 499 patients with acute febrile illness (50.2% accompanied by neurological symptoms) were tested during 2010-2014 by serological and molecular methods. Phlebovirus infection was detected in 40 (8%) patients, 25 of them presenting acute neurological infection. Most cases were observed in the summer, with a peak in August. Increased number of cases was observed in 2013, and three of them were observed in Athens. Toscana virus lineage C RNA was detected in one encephalitis case, while the serological results showed that most cases were caused by phleboviruses belonging to the sandfly fever Naples virus serocomplex. This study provided the first insight into the epidemiology of phleboviral disease in Greece.

Laboratory and surveillance studies following a suspected Dengue case in Greece, 2012

OBJECTIVES

To describe the laboratory assays used to investigate a suspected dengue case in summer 2012 in western Greece and to report the public health response.

DESIGN OF METHODS

Samples from the patient were tested for detection of Dengue virus (DENV) antibodies, NS1 antigen and RNA. Public health professionals interviewed residents of the village, and blood samples taken from 132 persons were tested for antibodies for DENV and West Nile virus (WNV). Samples from 10 persons who reported symptoms in the prior 15 days (including 3 persons who had fever at the time of sampling) were tested for DENV, WNV and additional arboviruses. Entomological missions were organized in the area of potential exposure to investigate the presence of competent DENV vectors.

RESULTS

Based on a combination of serological and molecular methods, DENV infection was excluded, and the problems in the serology, especially in the DENV NS1 antigen, were attributed to interfering factors. A 6.1% WNV seroprevalence was detected in the region, and phlebovirus IgM and IgG antibodies were detected in two of three persons who had fever at the time of sampling. Aedes albopictus adult mosquitoes were present in the region.

CONCLUSIONS

A multi-disciplinary field and laboratory investigation showed no evidence of DENV infection. There is a need for industries to improve the immunometric assays to avoid interference with rheumatoid or other factors, and increased awareness is needed for the evaluation of the diagnostic assays. The high WNV seroprevalence in the investigated region highlights the need for strengthening awareness on vector borne diseases. The presence of Ae. albopictus suggests that the possibility of introduction of DENV exists, and preparedness plans are needed.