Arbovirus Surveillance Research Articles

Mayaro virus in Latin America and the Caribbean.

ABSTRACTObjectives.To assess the distribution of Mayaro virus (MAYV) in Latin America and the Caribbean and evaluate existing country-level MAYV surveillance mechanisms.Methods.Research was conducted from May 2018 through May 2019 to collect data from academic literature on Mayaro fever in Latin America and the Caribbean. PubMed, ClinicalKey, Scopus, Nature, SciELO, LILACS, and Google Scholar were searched for peer-reviewed journal articles, and data from health authorities, including the Pan American Health Organization (PAHO) and ministries of health, was also sought. MAYV-related publications published from 1954 through 2019 were screened. Publications that added to the overall understanding of MAYV, including its geographical and epidemiological distribution, were included in this report.Results.A total of 901 MAYV cases have been reported in humans in countries in Latin America and the Caribbean. Since its discovery in 1954 in Trinidad and Tobago, MAYV has been isolated from individuals living in Argentina, Bolivia, Brazil, Ecuador, French Guiana, Haiti, Mexico, Panama, Peru, and Venezuela. Of those 901 cases, 42 of them were reported exclusively by health authorities. In contrast, 843 confirmed and presumptive autochthonous cases and an additional 16 imported cases were identified in academic literature. No country-level surveillance mechanisms for MAYV were recorded in academic literature or by health authorities.Conclusions.This report demonstrates that MAYV surveillance efforts are limited in comparison to the virus’s presence in Latin America and the Caribbean, highlighting the importance of enhancing arboviral surveillance systems in the affected countries.

A simple and rapid approach to prepare Sindbis and West Nile viral RNA controls for differentiation between positive samples and laboratory contamination

Reverse transcription-polymerase chain reaction (RT-PCR) is frequently used for surveillance and diagnosis of arboviruses and emerging viruses. A disadvantage of RT-PCR assays, especially nested assays, is the potential for false-positive results caused by laboratory contamination from either positive controls or positive samples. Positive reactors usually require sequence determination for confirmation which delay timeous reporting of a result. Thus, the aim of the study was to use a simple technique to prepare a positive control allowing true positives to be differentiated from laboratory contamination based on size differentiation for conventional PCR, or melt temperatures for real time assays. A flavivirus positive control and an alphavirus positive control were prepared for two RT-PCR assays that we are currently using for arbovirus surveillance in South Africa. Primers targeting a region of the partial genes of interest cloned in pGEM®T-easy were modified at the 5′ ends with non-viral nucleotides. The resulting amplicons were circularised, resulting in pGEM®T-easy constructs with 51 and 65 non-viral bases inserted into the partial flaviviral and alphaviral genes respectively and used as template for transcribing RNA. Sequence analysis was used to confirm the manipulation of the partial genes. Using virus specific primer pairs, viral RNA could be readily differentiated from the modified positive controls either by size differentiation, or melt temperature in a SYBR®Green real time RT-PCR. This study demonstrates how simple recombinant technology can be used to produce a positive control that has application in the laboratory for surveillance studies or as a diagnostic tool using synthetic genes to abrogate the requirement for handling infectious virus.

Utilising a novel surveillance system to enhance field screening activities for the leishmaniases

Over the last decade, an arbovirus surveillance system based on the preservation of nucleic acids (RNA/DNA) has been developed using Flinders Technology Associates (FTAⓇ) cards. Soaked in honey, FTAⓇ cards are applied in the field to detect arboviruses expectorated during mosquito sugar feeding. This technique has been shown to be inexpensive and efficient, and the implementation of this system for detecting parasites could be of international importance. As Leishmania parasites are highly prevalent in developing countries, FTAⓇ cards may offer an alternative inexpensive tool to enhance field surveillance activities for leishmaniasis. The simple approach of applying the cards in programs can substitute the necessary extensive training of personnel. In our hands, Leishmania macropodum DNA was shown to be stable on FTAⓇ cards during a 10-week time course, supporting their suitability for projects where direct access to laboratories is unobtainable and samples require storage prior to processing. This method may benefit programs in remote areas where accessibility to laboratory facilities are limited and samples need to be stored long-term.•This study found that FTA cards could be a valuable tool in the surveillance of leishmaniasis.•The method is based on the long-term preservation and detection of Leishmania DNA expectorated during insect sugar feeding.•The application of FTA cards can preclude the need to screen large samples and analysis of insect populations to provide evidence of disease transmission.

Importance of microenvironment to arbovirus vector distribution in an urban area, São Paulo, Brazil.

INTRODUCTION: The study of the landscape ecology, biological microhabitat, and epidemiological implications for the distribution of the main vectors Aedes aegypti and Aedes albopictus contribute to the prevention and control actions regarding the diseases they transmit. METHODS: This study sought to assess data on positive properties of the vector control program activities from 1998 to 2010. An entomological survey was also carried out on a sample of buildings collecting larvae and pupae from containers between October and April (spring / summer) from 2002 to 2005. We assessed the physico-chemical data of the water in 20% of positive containers. The vegetation and urbanization were assessed with the aid of satellite images and microenvironments were classified as urbanized, woods, and shrubs. The data were analyzed using statistical and geoprocessing software. RESULTS: Ae. aegypti and Ae. albopictus colonized all types of microhabitats and microenvironments, predominantly in the urbanized area, in isolation and in coexistence. The microhabitat of Ae. aegypti showed a temperature gradient greater than that of Ae. albopictus, and there was an association with urbanized areas for the first species and wooded areas for the last species. CONCLUSIONS: Landscape ecology and intra-urban differences favor different microclimates, which contribute to the coexistence of species in the urban environment in an area close to the forest, raising the risk of other arbovirus infections in urban areas. The ecological niche should be considered for Ae. albopictus. Entomological and virologic monitoring are suggested as arbovirus surveillance actions in urban infested centers near preserved forests.

Sensitivity and specificity of metatranscriptomics as an arbovirus surveillance tool

The ability to identify all the viruses within a sample makes metatranscriptomic sequencing an attractive tool to screen mosquitoes for arboviruses. Practical application of this technique, however, requires a clear understanding of its analytical sensitivity and specificity. To assess this, five dilutions (1:1, 1:20, 1:400, 1:8,000 and 1:160,000) of Ross River virus (RRV) and Umatilla virus (UMAV) isolates were spiked into subsamples of a pool of 100 Culex australicus mosquitoes. The 1:1 dilution represented the viral load of one RRV-infected mosquito in a pool of 100 mosquitoes. The subsamples underwent nucleic acid extraction, mosquito-specific ribosomal RNA depletion, and Illumina HiSeq sequencing. The viral load of the subsamples was also measured using reverse transcription droplet digital PCR (RT-ddPCR) and quantitative PCR (RT-qPCR). Metatranscriptomic sequencing detected both RRV and UMAV in the 1:1, 1:20 and 1:400 subsamples. A high specificity was achieved, with 100% of RRV and 99.6% of UMAV assembled contigs correctly identified. Metatranscriptomic sequencing was not as sensitive as RT-qPCR or RT-ddPCR; however, it recovered whole genome information and detected 19 other viruses, including four first detections for Australia. These findings will assist arbovirus surveillance programs in utilising metatranscriptomics in routine surveillance activities to enhance arbovirus detection.

Evaluation of honey-baited FTA cards in combination with different mosquito traps in an area of low arbovirus prevalence

BackgroundThe threat of mosquito-borne diseases is increasing in continental Europe as demonstrated by several autochthonous chikungunya, dengue and West Nile virus outbreaks. In Switzerland, despite the presence of competent vectors, routine surveillance of arboviruses in mosquitoes is not being carried out, mainly due to the high costs associated with the need of a constant cold chain and laborious processing of thousands of mosquitoes. An alternative approach is using honey-baited nucleic acid preserving cards (FTA cards) to collect mosquito saliva that may be analysed for arboviruses. Here, we evaluate whether FTA cards could be used to detect potentially emerging viruses in an area of low virus prevalence in combination with an effective mosquito trap.MethodsIn a field trial in southern Switzerland we measured side-by-side the efficacy of the BG-Sentinel 2, the BG-GAT and the Box gravid trap to catch Aedes and Culex mosquitoes in combination with honey-baited FTA cards during 80 trapping sessions of 48 hours. We then screened both the mosquitoes and the FTA cards for the presence of arboviruses using reverse-transcription PCR. The efficacy of the compared trap types was evaluated using generalized linear mixed models.ResultsThe Box gravid trap collected over 11 times more mosquitoes than the BG-GAT and BG-Sentinel 2 trap. On average 75.9% of the specimens fed on the honey-bait with no significant difference in feeding rates between the three trap types. From the total of 1401 collected mosquitoes, we screened 507 Aedes and 500 Culex females for the presence of arboviruses. A pool of six Cx. pipiens/Cx. torrentium mosquitoes and also the FTA card from the same Box gravid trap were positive for Usutu virus. Remarkably, only two of the six Culex mosquitoes fed on the honey-bait, emphasising the high sensitivity of the method. In addition, two Ae. albopictus collections but no FTA cards were positive for mosquito-only flaviviruses.ConclusionsBased on our results we conclude that honey-baited FTA cards, in combination with the Box gravid trap, are an effective method for arbovirus surveillance in areas of low prevalence, particularly where resources are limited for preservation and screening of individual mosquitoes.

Optimizing arbovirus surveillance using risk mapping and coverage modelling

ABSTRACTDiseases carried by mosquitoes and other arthropods endanger human health globally. Though costly, surveillance efforts are vital for disease control and prevention This paper describes an approach for strategically configuring targeted disease surveillance sites across a study area. The methodology combines risk index mapping and spatial optimization modelling. The risk index is used to identify demand for surveillance, and the maximum covering location problem is used to select a specified number of candidate surveillance sites that covers the maximum amount of risk. The approach is demonstrated using a case study where optimal locations for sentinel surveillance sites are selected for the purposes of detecting eastern equine encephalitis virus in a county in the state of Florida. Optimal sentinel sites were selected under a number of scenarios that modelled different target populations (horses or humans), coverage distances (0.5, 1.0, and 1.5 km), and numbers of sites to select (1–12). Sentinel site selections for the horse and human models displayed different spatial patterns, with horse sites located largely in the west-central region and human ones in the north-central. Minor amounts of spatial overlap between the horse and human sites were observed, especially as coverage distances and numbers of sites were increased. Additionally, a near linear increase in risk coverage was observed as sites were incrementally added to the scenarios. This finding suggests that the number of sentinel sites within the ranges explored should be based on the maximum that can be funded, since they provide similar levels of benefit.

Emergence of the Asian lineage of Zika virus in Angola: an outbreak investigation

SummaryBackgroundZika virus infections and suspected microcephaly cases have been reported in Angola since late 2016, but no data are available about the origins, epidemiology, and diversity of the virus. We aimed to investigate the emergence and circulation of Zika virus in Angola.MethodsDiagnostic samples collected by the Angolan Ministry of Health as part of routine arboviral surveillance were tested by real-time reverse transcription PCR by the Instituto Nacional de Investigação em Saúde (Ministry of Health, Luanda, Angola). To identify further samples positive for Zika virus and appropriate for genomic sequencing, we also tested samples from a 2017 study of people with HIV in Luanda. Portable sequencing was used to generate Angolan Zika virus genome sequences from three people positive for Zika virus infection by real-time reverse transcription PCR, including one neonate with microcephaly. Genetic and mobility data were analysed to investigate the date of introduction and geographical origin of Zika virus in Angola. Brain CT and MRI, and serological assays were done on a child with microcephaly to confirm microcephaly and assess previous Zika virus infection.FindingsSerum samples from 54 people with suspected acute Zika virus infection, 76 infants with suspected microcephaly, 24 mothers of infants with suspected microcephaly, 336 patients with suspected dengue virus or chikungunya virus infection, and 349 samples from the HIV study were tested by real-time reverse transcription PCR. Four cases identified between December, 2016, and June, 2017, tested positive for Zika virus. Analyses of viral genomic and human mobility data suggest that Zika virus was probably introduced to Angola from Brazil between July, 2015, and June, 2016. This introduction probably initiated local circulation of Zika virus in Angola that continued until at least June, 2017. The infant with microcephaly in whom CT and MRI were done had brain abnormalities consistent with congenital Zika syndrome and serological evidence for Zika virus infection.InterpretationOur analyses show that autochthonous transmission of the Asian lineage of Zika virus has taken place in Africa. Zika virus surveillance and surveillance of associated cases of microcephaly throughout the continent is crucial.FundingRoyal Society, Wellcome Trust, Global Challenges Research Fund (UK Research and Innovation), Africa Oxford, John Fell Fund, Oxford Martin School, European Research Council, Departamento de Ciência e Tecnologia/Ministério da Saúde/National Council for Scientific and Technological Development, and Ministério da Educação/Coordenação de Aperfeicoamento de Pessoal de Nível Superior.

Detecting space-time clusters of dengue fever in Panama after adjusting for vector surveillance data.

Long term surveillance of vectors and arboviruses is an integral aspect of disease prevention and control systems in countries affected by increasing risk. Yet, little effort has been made to adjust space-time risk estimation by integrating disease case counts with vector surveillance data, which may result in inaccurate risk projection when several vector species are present, and when little is known about their likely role in local transmission. Here, we integrate 13 years of dengue case surveillance and associated Aedes occurrence data across 462 localities in 63 districts to estimate the risk of infection in the Republic of Panama. Our exploratory space-time modelling approach detected the presence of five clusters, which varied by duration, relative risk, and spatial extent after incorporating vector species as covariates. The Ae. aegypti model contained the highest number of districts with more dengue cases than would be expected given baseline population levels, followed by the model accounting for both Ae. aegypti and Ae. albopictus. This implies that arbovirus case surveillance coupled with entomological surveillance can affect cluster detection and risk estimation, potentially improving efforts to understand outbreak dynamics at national scales.

Detection of Antibodies to Spotted Fever Group Rickettsiae and Arboviral Coinfections in Febrile Individuals in 2014-2015 in Southern Coastal Ecuador.

Tick-borne diseases (TBDs) are a growing public health threat and are increasingly identified as the cause of undifferentiated febrile illness. There is a significant gap in our understanding of ticks and their associated pathogens in Ecuador. An arboviral surveillance study allowed us to explore potential exposure to TBDs in febrile subjects. We tested plasma samples from 222 febrile subjects for spotted fever group rickettsial (SFGR) antibodies from southern coastal Ecuador in 2014-2015 via ELISA. Fifty-five (25%) subjects had evidence of anti-SFRG IgG or IgM antibodies. Although attempts to detect Rickettsia species in plasma by polymerase chain reaction were unsuccessful, these preliminary data suggest the possibility of endemic SFGR transmission in Ecuador. To better understand the burden and entomological risk for TBDs in Ecuador, future studies should expand TBD surveillance in humans, document common human-biting ticks, and measure pathogen carriage rates in questing ticks.

Host Associations Of Biting Midges (Diptera: Ceratopogonidae: Culicoides) Near Sentinel Chicken Surveillance Locations In Florida, USA.

Quantifying host use is important for understanding transmission of vector-borne pathogens. Despite the importance of biting midges (Diptera: Ceratopogonidae) in pathogen transmission, the vector-host relationships of most Culicoides species are poorly documented, even in locations where active arbovirus surveillance is conducted. Polymerase chain reaction-based blood-meal analysis was performed on 663 blood-engorged Culicoides females collected by 7 Florida mosquito control districts at 24 sentinel chicken arbovirus surveillance sites in 2017. A total of 638 blood meals were successfully analyzed to determine host species source, representing 11 Culicoides species. The most commonly bitten host was domestic chicken (Gallus gallus) (presumably sentinel chickens), constituting 565 of 638 (88.6%) the total blood meals. Other common hosts included humans (5.8%), white-tailed deer (Odoocoileus virginianus) (2.5%), and brown basilisk (Basiliscus vittatus) (1.6%). Significant differences in distribution of mammal and avian blood meals were found for a number of Culicoides species, and these patterns did not vary across locations. These results indicate that sentinel chickens are exposed to bites by Culicoides, potentially exposing them to Culicoides-borne pathogens. The findings that vertebrate host use was consistent across locations suggests that each Culicoides species has affinity for one or more specific animal groups, and does not feed randomly upon available animals.

Postnatally Acquired Zika

Research Article| September 01 2019 Postnatally Acquired Zika AAP Grand Rounds (2019) 42 (3): 33. https://doi.org/10.1542/gr.42-3-33 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Postnatally Acquired Zika. AAP Grand Rounds September 2019; 42 (3): 33. https://doi.org/10.1542/gr.42-3-33 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search toolbar search search input Search input auto suggest filter your search All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: zika virus, zika virus infections Source: Lindsey NP, Porse CC, Potts E, et al. Postnatally acquired Zika virus disease among children, United States, 2016–2017. Clin Infect Dis. 2019 11 March [published online ahead of print]; doi: https://doi.org/10.1093/cid/ciz195Google Scholar Investigators from multiple institutions conducted a case series to describe the clinical signs and symptoms of children with postnatally acquired Zika virus disease. Cases were defined as those who met the national surveillance definition for confirmed or probable disease, had illness onset in 2016 or 2017, were reported to the national arboviral disease surveillance system, and resided in 1 of 10 participating US states. Investigators abstracted demographic, clinical, and laboratory data for each case from local health department surveillance data obtained from medical records, health care providers, and patients and guardians. Investigators grouped pediatric cases (age <18 years) into 2 age strata (1–11 and 12–17 years) and compared clinical information and outcomes between the 2 age groups by using chi-square tests. Investigators also matched each pediatric case 1:1 to an adult case (18–49 years old) by state of residence and case status (ie, confirmed or probable). Characteristics of pediatric cases were compared to those of matched adult cases by using logistic regression. There were 141 identified pediatric cases, 64% of which were in children 12–17 years old. Nearly all (N=139) acquired Zika during travel outside of the United States, with the most common countries being Mexico (N=28) and the Dominican Republic (N=26). The 4 most common signs and symptoms of Zika virus disease in children were rash (94%), fever (74%), arthralgia (48%), and conjunctivitis (36%); 18% of children had all 4 signs and symptoms. No children had neurological signs or symptoms consistent with meningitis, encephalitis, or Guillain-Barré syndrome. Significantly more children 12–17 years old had fever, arthralgia, and myalgia than did children 1–11 years old, and significantly more adults had arthralgia, arthritis, edema, and myalgia than did children. Only 1 child was hospitalized, and 20% of children were treated in the ED. No children died. The authors conclude that postnatally acquired Zika virus disease appears to be a mild illness in children that often manifests with rash, fever, and/or arthralgia. Dr Brady has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device. The authors conclude that postnatally acquired Zika virus infection resembles other common viral exanthema, including rubella, measles, adenovirus, and enterovirus.1 All of these infections may be associated with maculopapular rashes. Both measles and rubella are preventable with vaccine, so asking about immunization status is important. Although postnatally acquired rubella is extremely rare,2 1,109 confirmed measles cases have been reported in the United States between January 1 and July 3, 2019.3 Some of these cases have been linked to travelers who brought measles back from countries where large measles outbreaks were occurring. A second important question to ask is where the child has traveled. In 2015, Zika virus was identified for the first... You do not currently have access to this content.

Discovery of Cocirculating Ross River Virus and Barmah Forest Virus At Wide Bay Military Training Area, Northeastern Australia.

An arbovirus surveillance military exercise was conducted to assess the risk of Ross River virus (RRV) and Barmah Forest virus (BFV) in the Australian Defence Force (ADF) Wide Bay training area (WBTA), northeastern Australia, in April 2018. Of the 5,540 female mosquitoes collected, 3,702 were screened for RRV and BFV by quantitative reverse transcription-polymerase chain reaction in a field laboratory. One pool of Verrallina funerea was positive for RRV and 8 pools (7 pools of Aedes vigilax and 1 pool of Culex annulirostris) were positive for BFV. Phylogenetic analysis of the complete nucleotide sequence of the E2 protein subgrouped both RRV and BFV with viruses previously isolated from human infections, indicating the potential risk of RRV and BFV infection to ADF personnel while training in WBTA. This is the 1st time that both RRV and BFV have been detected in a military training area.

Co-circulation and characterization of novel African arboviruses (genus Ephemerovirus) in cattle, Mayotte island, Indian Ocean, 2017.

SummaryMayotte is an island located in the Mozambique Channel, between Mozambique and Madagascar, in the South Western Indian Ocean region. A severe syndrome of unknown aetiology has been observed seasonally since 2009 in cattle (locally named “cattle flu”), associated with anorexia, nasal discharge, hyperthermia and lameness. We sampled blood from a panel of those severely affected animals at the onset of disease signs and analysed these samples by next‐generation sequencing. We first identified the presence of ephemeral bovine fever viruses (BEFV), an arbovirus belonging to the genus Ephemerovirus within the family Rhabdoviridae, thus representing the first published sequences of BEFV viruses of African origin. In addition, we also discovered and genetically characterized a potential new species within the genus Ephemerovirus, called Mavingoni virus (MVGV) from one diseased animal. Finally, both MVGV and BEFV have been identified in cattle from the same herd, evidencing a co‐circulation of different ephemeroviruses on the island. The clinical, epidemiological and virological information strongly suggests that these viruses represent the etiological agents of the observed “cattle flu” within this region. This study highlights the importance of the strengthening and harmonizing arboviral surveillance in Mayotte and its neighbouring areas, including Africa mainland, given the importance of the diffusion of infectious diseases (such as BEFV) mediated by animal and human movements in the South Western Indian Ocean area.

The discovery and global distribution of novel mosquito-associated viruses in the last decade (2007-2017).

In the last decade, virus hunting and discovery has gained pace. This achievement has been driven by three major factors: (a) advancements in sequencing technologies, (b) scaled-up routine arbovirus surveillance strategies, and (c) the "hunt" for emerging pathogens and novel viruses. Many novel viruses have been discovered from a myriad of hosts, vectors, and environmental samples. To help promote understanding of the global diversity and distribution of mosquito-associated viruses and facilitate future studies, we review mosquito-associated viruses discovered between years 2007 and 2017, across the world. In the analyzed period, novel mosquito-associated viruses belonging to 25 families and a general group of unclassified viruses were categorized. The top three discovered novel mosquito-associated viruses belonged to families Flaviviridae (n=32), Rhabdoviridae (n=16), and Peribunyaviridae (n=14). Also, 67 unclassified viruses were reported. Majority of these novel viruses were identified from Culex spp, Anopheles spp, Aedes spp, and Mansonia spp mosquitoes, respectively. Notably, the number of these discovered novels is not representative of intercontinental virus diversity but rather is influenced by the number of studies done in the study period. Some of these newly discovered mosquito-associated viruses have medical significance, either directly or indirectly. For instance, in the study period, 14 novel mosquito-borne viruses that infect mammalian cells in vitro were reported. These viruses pose a danger to the global health security on emerging viral diseases. On the other hand, some of the newly discovered insect specific viruses described herein have potential application as future biocontrol and vaccine agents against known pathogenic arboviruses. Overall, this review outlines the crucial role played by mosquitoes as viral vectors in the global virosphere.

Five Emerging Neuroinvasive Arboviral Diseases: Cache Valley, Eastern Equine Encephalitis, Jamestown Canyon, Powassan, and Usutu

There are many arthropod-borne viruses (arboviruses) capable of neuroinvasion, with West Nile virus being one of the most well known. In this review, we highlight five rarer emerging or reemerging arboviruses capable of neuroinvasion: Cache Valley, eastern equine encephalitis, Jamestown Canyon, Powassan, and Usutu viruses. Cache Valley and Jamestown Canyon viruses likely circulate throughout most of North America, while eastern equine encephalitis and Powassan viruses typically circulate in the eastern half. Usutu virus is not currently circulating in North America, but has the potential to be introduced in the future given similar climate, vectors, and host species to Europe (where it has been circulating). Health care providers should contact their state or local health departments with any questions regarding arboviral disease surveillance, diagnosis, treatment, or prevention. To prevent neuroinvasive arboviral diseases, use of insect repellent and other mosquito and tick bite prevention strategies are key.

European Aedes caspius mosquitoes are experimentally unable to transmit Zika virus

BackgroundAedes caspius (Pallas, 1771) is a floodwater mosquito species widely distributed in the Western Palaearctic. As an anthropophilic species, its role as an arbovirus vector may be the key for understanding the transmission cycle of certain diseases in Europe such as Zika virus (ZIKV). Concerning vector competence for ZIKV, studies related to Ae. caspius are still scarce. ZIKV is an arbovirus that has provoked a widespread epidemic in the Pacific region (2007–2013) and in the Americas (2015–2016). ZIKV is associated with serious neurological injuries (e.g. microcephaly) and Guillain-Barré syndrome. Due to the ZIKV epidemics in the American continent, some viraemic travellers coming from endemic countries have been reported in Europe. More knowledge is therefore required to define the susceptibility of autochthonous mosquito species such as Ae. caspius for ZIKV in order to improve arbovirus surveillance and control programmes. In the present study, the vector competence of a European population of Ae. caspius was evaluated for two ZIKV lineages, the Suriname ZIKV strain (Asian lineage) and the MR766 ZIKV strain (African I lineage). Females were tested at 7, 14 and 21 days post-exposure (dpe) to infectious blood meals. An Ae. aegypti PAEA strain was used as a positive control.ResultsAedes caspius presented low susceptibility to ZIKV infection and the virus was only detected by RT-qPCR in body samples. Low viral loads were detected for the MR766 strain at 7 dpe and for the Suriname strain at 14 and 21 dpe. Aedes caspius was unable to produce a disseminated infection and virus transmission at any of the tested time points. Using Ae. aegypti PAEA strain, infection, dissemination and transmission rates were calculated for the Suriname ZIKV strain (Asian lineage) at each time point. For the MR766 ZIKV strain (African I lineage), while only infection rates were estimated at each time point, no dissemination or transmission were detected in either species.ConclusionsThe results of the present study reveal that the tested Ae. caspius population has a strong midgut escape barrier that limits the dissemination or transmission of the virus. As such, it seems unlikely that European Ae. caspius mosquitoes could be involved in ZIKV transmission if ZIKV was introduced into Europe. This information may help in designing a better strategy to European surveillance and control programmes for ZIKV.

Spread of two Zika virus lineages in Midwest Brazil

Zika virus (ZIKV) has been intensively studied in South America and across the globe since 2015–2016 epidemics. However, in Brazil - the largest and the most affected country in terms of human infection by this virus, most of the viral molecular information is restricted to metropolitan centers distributed along the Brazilian coast and almost no information is known about the virus spread in most difficult access areas such as the Midwest region of the country. Here, we report two ZIKV complete genomes from samples obtained during arboviral surveillance at the Sinop city, southern border of the Amazonian forest, Midwest Brazil in 2015. Our results show that the virus was introduced in this region through two independent introductions: one occurred at the end of 2014, around the period that the virus was already distributed in other regions of the country and abroad, and a second at the end of 2015. Moreover, these genomes were clustered with other viral strains sampled at distant Brazilian states in line with other findings about the rapid spread of the virus throughout the country.

First Reported Human Cases of Leptospirosis in the United States Virgin Islands in the Aftermath of Hurricanes Irma and Maria, September–November 2017

ObjectiveFollowing Hurricanes Irma and Maria, the first case of human leptospirosis ever identified in the US Virgin Islands (USVI) was reported to the Virgin Islands Department of Health. Leptospirosis is a potentially fatal bacterial disease caused by Leptospira species found in animal urine and urine-contaminated water and soil. Outbreaks can occur following extreme weather events.MethodAdditional cases of leptospirosis were identified in the 2.5 months post-hurricanes by reviewing emergency department (ED) records from territorial hospitals for patients demonstrating leptospirosis-consistent symptoms, testing symptomatic patients previously enrolled in the USVI arbovirus surveillance system (VIASS), and adding leptospirosis testing prospectively to VIASS. Available patient sera underwent local rapid diagnostic testing for anti-Leptospira IgM followed by confirmatory microscopic agglutination testing at the US Centers for Disease Control and Prevention. Water was collected from cisterns with epidemiologic links to confirmed cases and tested by real-time PCR (qPCR) for pathogenic Leptospira spp.ResultsSixteen retrospectively identified symptomatic patients were enrolled in VIASS; 15 with available samples tested negative. Based on review of 5226 ED charts, 6 patients were further investigated; of these, 5 were tested of which 1 was positive. Prospective leptospirosis surveillance tested 57 additional patients; of these, 1 was positive. Water from 1 of 5 tested cisterns was found positive by qPCR.ConclusionsThis investigation documents the first 3 cases of leptospirosis reported in the USVI and demonstrates how VIASS successfully was adapted to establish leptospirosis surveillance. Contaminated cistern water was identified as a potential source for Leptospira spp. transmission, highlighting the need for additional post-hurricane remediation and disinfection guidance.

Arbovirus surveillance using FTATM cards in modified CO2 -baited encephalitis virus surveillance traps in the Northern Territory, Australia.

In 2016, modified CO2 -baited encephalitis virus surveillance (EVS) traps were evaluated for flavivirus surveillance in the Northern Territory, Australia. The traps were fitted with honey-soaked nucleic acid preservation cards (FTATM ) for mosquitoes to expectorate virus while feeding on the cards. Cards were tested for the presence of selected arboviruses, with two cards testing positive for Kunjin virus and Alfuy, while sentinel chickens tested in parallel also showed Kunjin virus activity at the same time. The results from the cards and vector mosquito feeding rates indicate that CO2 -baited EVS traps coupled with honey-baited FTATM cards are an effective tool for broad-scale arbovirus surveillance.