- A Serosurvey of Flavivirus Infection in Horses and Birds in Slovakia. [Journal Article]
- VBVector Borne Zoonotic Dis 2018 Feb 13
- In central Europe, at least three flaviviruses circulate among vectors and vertebrate hosts. West Nile virus (WNV) and Usutu virus (USUV) are mosquito-borne viruses maintained in the nature by enzoot...
In central Europe, at least three flaviviruses circulate among vectors and vertebrate hosts. West Nile virus (WNV) and Usutu virus (USUV) are mosquito-borne viruses maintained in the nature by enzootic cycle between mosquitoes and birds. Tick-borne encephalitis virus (TBEV) is a flavivirus causing annual human cases in Slovakia. The aim of this study is the prevalence assessment of flavivirus infections in horses (n = 145) and birds (n = 109) by enzyme-linked immunosorbent assay (ELISA) and confirmation by neutralization test (VNT). WNV antibodies have been detected in 11.7% of tested horses and 11.9% of tested birds and confirmed in 6.9% of horse and 9.2% of bird samples. None of the WNV seropositive or dubious horses had WNV IgM (ELISA), and none of the tested horses had USUV neutralizing antibodies. Autochthonous WNV infections have been confirmed in 16.7% of horses without international travelling history. Most of them were from western Slovakia with known endemic WNV transmission. An autochthonous WNV infection in a horse from highland area of Kremnické vrchy (central Slovakia) with unknown data of WNV circulation and without travelling history was detected. TBEV antibody was detected in 6.2% of horses and in 3.4% has been confirmed. In two horses, WNV and TBEV infection could not be distinguished. Confirmed WNV seropositive were eight raptors showing nonspecific signs or suffering from trauma, one white stork, and one house sparrow. The sparrow was caught in a locality in eastern Slovakia, where WNV RNA had been previously detected in sparrows. USUV neutralizing antibodies were present in pooled sample from four Eurasian great tits. Because of insufficient volume, TBEV VNT was not carried out in birds. Results further prove the endemicity of WNV and other vector-borne flaviviruses in natural and accidental hosts in Slovakia, giving better insight in flavivirus epidemiology in European countries in general.
- Zika, chikungunya and dengue: the causes and threats of new and re-emerging arboviral diseases. [Review]
- BGBMJ Glob Health 2018; 3(Suppl 1):e000530
- The recent emergence and re-emergence of viral infections transmitted by vectors-Zika, chikungunya, dengue, Japanese encephalitis, West Nile, yellow fever and others-is a cause for international conc...
The recent emergence and re-emergence of viral infections transmitted by vectors-Zika, chikungunya, dengue, Japanese encephalitis, West Nile, yellow fever and others-is a cause for international concern. Using as examples Zika, chikungunya and dengue, we summarise current knowledge on characteristics of the viruses and their transmission, clinical features, laboratory diagnosis, burden, history, possible causes of the spread and the expectation for future epidemics. Arboviruses are transmitted by mosquitoes, are of difficult diagnosis, can have surprising clinical complications and cause severe burden. The current situation is complex, because there is no vaccine for Zika and chikungunya and no specific treatment for the three arboviruses. Vector control is the only comprehensive solution available now and this remains a challenge because up to now this has not been very effective. Until we develop new technologies of control mosquito populations, the globalised and urbanised world we live in will remain vulnerable to the threat of successive arbovirus epidemics.
- Antiviral Immunity and Virus-Mediated Antagonism in Disease Vector Mosquitoes. [Review]
- TMTrends Microbiol 2018 Jan 29
- More than 100 pathogens, spanning multiple virus families, broadly termed 'arthropod-borne viruses (arboviruses)' have been associated with human and/or animal diseases. These viruses persist in natu...
More than 100 pathogens, spanning multiple virus families, broadly termed 'arthropod-borne viruses (arboviruses)' have been associated with human and/or animal diseases. These viruses persist in nature through transmission cycles that involve alternating replication in susceptible vertebrate and invertebrate hosts. Collectively, these viruses are among the greatest burdens to global health, due to their widespread prevalence, and the severe morbidity and mortality they cause in human and animal hosts. Specific examples of mosquito-borne pathogens include Zika virus (ZIKV), West Nile virus (WNV), dengue virus serotypes 1-4 (DENV 1-4), Japanese encephalitis virus (JEV), yellow fever virus (YFV), chikungunya virus (CHIKV), and Rift Valley fever virus (RVFV). Interactions between arboviruses and the immune pathways of vertebrate hosts have been extensively reviewed. In this review we focus on the antiviral immune pathways present in mosquitoes. We also discuss mechanisms by which mosquito-borne viruses may antagonize antiviral pathways in disease vectors. Finally, we elaborate on the possibility that mosquito-borne viruses may be engaged in an evolutionary arms race with their invertebrate vector hosts, and the possible implications of this for understanding the transmission of mosquito-borne viruses.
- Development, Optimization, and Field Evaluation of the Novel Collapsible Passive Trap for Collection of Mosquitoes. [Journal Article]
- JMJ Med Entomol 2018 Jan 29
- Disease surveillance for mosquito-borne pathogens in remote areas can be challenging. Most traps used to collect mosquitoes either need a source of electricity or are bulky and inflexible, making tra...
Disease surveillance for mosquito-borne pathogens in remote areas can be challenging. Most traps used to collect mosquitoes either need a source of electricity or are bulky and inflexible, making transportation awkward. To reduce these issues we developed three Collapsible Passive Traps (CPTs) and conducted trials in Cairns, Australia to evaluate the optimal design for a CPT and compared them to traditionally-used traps such as Centers for Disease Control and Prevention (CDC) and Encephalitis Vector Surveillance (EVS) light traps. We found that two of the CPTs collected comparable numbers of mosquitoes and that one of the CPTs outperformed the CDC light trap in collecting Aedes species. Mosquitoes did not have to pass through a fan while entering the CPT, and thus were not damaged and were often alive. Our results suggest that the CPT can be an effective trap for mosquito surveillance, especially in remote areas.
- [Fever in a returning traveler from Tuscany]. [Journal Article]
- RMRev Med Suisse 2018 Jan 31; 14(592):294-296
- Arbovirus infections are emerging pathogens leading sometimes to severe disease. This virus is transmitted by sandflies in the Mediterranean countries during the summer season. The disease is often a...
Arbovirus infections are emerging pathogens leading sometimes to severe disease. This virus is transmitted by sandflies in the Mediterranean countries during the summer season. The disease is often asymptomatic but can also cause an influenza-like illness and aseptic meningitis or encephalitis. The treatment is supportive and preventive measures should be taken in order to avoid an infection when travelling to the affected areas. The differential diagnosis of fever in the returning traveler from southern European countries should include Toscana virus.
- Development and Validation of a Serologic Test Panel for Detection of Powassan Virus Infection in U.S. Patients Residing in Regions Where Lyme Disease Is Endemic. [Journal Article]
- MmSphere 2018 Jan-Feb; 3(1)
- Powassan virus (POWV) is an emerging tick-borne arbovirus presenting a public health threat in North America. POWV lineage II, also known as deer tick virus, is the strain of the virus most frequentl...
Powassan virus (POWV) is an emerging tick-borne arbovirus presenting a public health threat in North America. POWV lineage II, also known as deer tick virus, is the strain of the virus most frequently found in Ixodes scapularis ticks and is implicated in most cases of POWV encephalitis in the United States. Currently, no commercial tests are available to detect POWV exposure in tick-borne disease (TBD) patients. We describe here the development and analytical validation of a serologic test panel to detect POWV infections. The panel uses an indirect enzyme immunoassay (EIA) to screen. EIA-positive samples reflex to a laboratory-developed, POWV-specific immunofluorescence assay (IFA). The analytical sensitivity of the test panel was 89%, and the limit of detection was a plaque reduction neutralization test (PRNT) titer of 1:20. The analytical specificity was 100% for the IgM assay and 65% for the IgG assay when heterologous-flavivirus-positive samples were tested. On samples collected from regions where Lyme disease is endemic, seroprevalence for POWV in TBD samples was 9.4% (10 of 106) versus 2% when tested with non-TBD samples (2 of 100, P = 0.034). No evidence of POWV infection was seen in samples collected from a region where Lyme disease was not endemic (0 of 22). This test panel provides a sensitive and specific platform for detecting a serologic response to POWV early in the course of infection when neutralizing antibodies may not be detectable. Combined with clinical history, the panel is an effective tool for identifying acute POWV infection. IMPORTANCE Approximately 100 cases of POWV disease were reported in the United States over the past 10 years. Most cases have occurred in the Northeast (52) and Great Lakes (45) regions (https://www.cdc.gov/powassan/statistics.html). The prevalence of POWV in ticks and mammals is increasing, and POWV poses an increasing threat in a greater geographical range. In areas of the Northeast and Midwest where Lyme disease is endemic, POWV testing is recommended for patients with a recent tick bite, patients with Lyme disease who have been treated with antibiotics, or patients with a tick exposure who have tested negative for Lyme disease or other tick-borne illnesses and have persistent symptoms consistent with posttreatment Lyme disease. Testing could also benefit patients with tick exposure and unexplained neurologic symptoms and chronic fatigue syndrome (CFS) patients with known tick exposure. Until now, diagnostic testing for Powassan virus has not been commercially available and has been limited to patients presenting with severe, neurologic complications. The lack of routine testing for Powassan virus in patients with suspected tick-borne disease means that little information is available regarding the overall prevalence of the virus and the full spectrum of clinical symptoms associated with infection. As Ixodes scapularis is the tick vector for Powassan virus and multiple other tick-borne pathogens, including the Lyme disease bacterium, Borrelia burgdorferi, the clinical presentations and long-term outcomes of Powassan virus infection and concurrent infection with other tick-borne disease pathogens remain unknown.
- West Nile Virus and Other Nationally Notifiable Arboviral Diseases - United States, 2016. [Journal Article]
- MMMMWR Morb Mortal Wkly Rep 2018 Jan 12; 67(1):13-17
- Arthropod-borne viruses (arboviruses) are transmitted to humans primarily through the bites of infected mosquitoes and ticks. West Nile virus (WNV) is the leading cause of domestically acquired arbov...
Arthropod-borne viruses (arboviruses) are transmitted to humans primarily through the bites of infected mosquitoes and ticks. West Nile virus (WNV) is the leading cause of domestically acquired arboviral disease in the continental United States (1,2). Other arboviruses, including La Crosse, Powassan, Jamestown Canyon, St. Louis encephalitis, and eastern equine encephalitis viruses, cause sporadic cases of disease and occasional outbreaks. This report summarizes surveillance data reported to CDC for 2016 for nationally notifiable arboviruses. It excludes dengue, chikungunya, and Zika viruses, as these are primarily nondomestic viruses typically acquired through travel. Forty-seven states and the District of Columbia (DC) reported 2,240 cases of domestic arboviral disease, including 2,150 (96%) WNV disease cases. Of the WNV disease cases, 1,310 (61%) were classified as neuroinvasive disease (e.g., meningitis, encephalitis, acute flaccid paralysis), for a national incidence of 0.41 cases per 100,000 population. After WNV, the most frequently reported arboviruses were La Crosse (35 cases), Powassan (22), and Jamestown Canyon (15) viruses. Because arboviral diseases continue to cause serious illness, maintaining surveillance is important to direct prevention activities.
- Comparative analysis of genomes of tick-borne encephalitis virus strains isolated from mosquitoes and ticks. [Journal Article]
- VVVopr Virusol 2017; 62(1):30-5
- The tick-borne encephalitis virus (TBEV) strain Lazo MP36 was isolated from the pool of mosquitoes Aedes vexans collected in Lazo region of Khabarovsk territory in August 2014. Phylogenetic analysis ...
The tick-borne encephalitis virus (TBEV) strain Lazo MP36 was isolated from the pool of mosquitoes Aedes vexans collected in Lazo region of Khabarovsk territory in August 2014. Phylogenetic analysis of the strain Lazo MP36 complete genome (GenBank accession number KT001073) revealed its correspondence to the TBEV Far Eastern subtype and differences from the following strains: 1) from ticks Ixodes persulcatus P. Schulze, 1930 [vaccine strain 205 (JX498939) and strains Khekhtzir 1230 (KF880805), Chichagovka (KP844724), Birobidzhan 1354 (KF880805) isolated in 2012-2013]; 2) from mosquitoes [strain Malyshevo (KJ744034) isolated in 1978 from Aedes vexans nipponii in Khabarovsk territory; strain Sakhalin 6-11 isolated from the pool of mosquitoes in 2011 (KF826916)]; 3) from human brain [vaccine strain Sofjin (JN229223), Glubinnoe/2004(DQ862460). Kavalerovo (DQ862460), Svetlogorie (DQ862460)]. The fusion peptide necessary for flavivirus entry to cells of the three TBEV strains isolated from mosquitoes (Lazo MP36, Malyshevo and Sakhalin 6-11) has the canonical structure 98-DRGWGNHCGLFGKGSI-113 for the tick-borne flaviviruses. Amino acid transition H104G typical for the mosquito-borne flaviviruses was not found. Structures of 5’- and 3’-untranslated (UTR) regions of the TBEV strains from mosquitoes were 85-98% homologous to the TBEV strains of all subtypes without recombination with mosquito-borne flaviviruses found in the Far East of Russia. Secondary structures of 5’- and 3'-UTR as well as cyclization sequences (CS) of types a and B are highly homologous for all TBEV isolates independently of the biological hosts and vectors. similarity of the genomes of the TBEV isolates from mosquitoes, ticks and patients as well as pathogenicity of the isolates for new-borne laboratory mice and tissue cultures might suggest a possible role of mosquitoes in the TBEV circulation in natural foci as an accidental or additional virus carrier.
- High Seroprevalence of Jamestown Canyon Virus among Deer and Humans, Nova Scotia, Canada. [Journal Article]
- EIEmerg Infect Dis 2018; 24(1):118-121
- Using residual serum samples from Nova Scotia, Canada, we found that 87.8% of tested deer and an estimated 20.6% of the human population were infected with Jamestown Canyon virus. Human seropositivit...
Using residual serum samples from Nova Scotia, Canada, we found that 87.8% of tested deer and an estimated 20.6% of the human population were infected with Jamestown Canyon virus. Human seropositivity reached 48.2% in 1 region. This virus may be an underrecognized cause of disease in Nova Scotia.
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- Encephalitis in US Children. [Review]
- IDInfect Dis Clin North Am 2018; 32(1):145-162
- Encephalitis is an uncommon but severe disease characterized by neurologic dysfunction with central nervous system inflammation. Children with encephalitis should receive supportive care and empiric ...
Encephalitis is an uncommon but severe disease characterized by neurologic dysfunction with central nervous system inflammation. Children with encephalitis should receive supportive care and empiric therapies for common and treatable causes while prioritizing diagnostic evaluation for common, treatable, and high-risk conditions. Even with an extensive diagnostic workup, an infectious cause is identified in less than half of cases, suggesting a role for postinfectious or noninfectious processes.