Zika virus (ZIKV) is a mosquito-borne flavivirus first isolated in Uganda from a sentinel monkey in 1947. Mosquito and sentinel animal surveillance studies have demonstrated that ZIKV is endemic to ...Africa and Southeast Asia, yet reported human cases are rare, with <10 cases reported in the literature. In June 2007, an epidemic of fever and rash associated with ZIKV was detected in Yap State, Federated States of Micronesia. We report the genetic and serologic properties of the ZIKV associated with this epidemic.
Chikungunya virus (CHIKV), a mosquito-borne alphavirus, is endemic in Africa and Asia. In 2005-2006, CHIKV epidemics were reported in islands in the Indian Ocean and in southern India. We present ...data on laboratory-confirmed CHIKV infections among travelers returning from India to the United States during 2006.
We assessed IgM detection in Zika patients from the 2016 outbreak in Miami-Dade County, Florida, USA. Of those with positive or equivocal IgM after 12-19 months, 87% (26/30) had IgM 6 months later. ...In a survival analysis, ≈76% had IgM at 25 months. Zika virus IgM persists for years, complicating serologic diagnosis.
Chikungunya virus (CHIKV) represents an emerging health threat to the United States as humans amplify CHIKV and vectors that transmit CHIKV are present in the country. To minimize the risk of CHIKV ...spread in the United States, healthcare providers and public health officials should be educated about recognition, diagnosis, and reporting of CHIK cases.
Background.
Chikungunya virus (CHIKV) represents a threat to the United States, because humans amplify CHIKV and vectors that transmit CHIKV are present.
Methods.
We described the epidemiology of laboratory-confirmed chikungunya fever (CHIK) cases in the United States in 1995–2009 and compared states with CHIKV vectors with states with returning viremic CHIK cases. For 2006–2009, we evaluated reporting of CHIK cases to ArboNET, the arboviral surveillance system.
Results.
In 1995–2009, 109 CHIK cases were identified in the United States; all adult travelers. Sixty-two subjects (57%) had recently visited India, and 13 (12%) had CHIKV viremia. Of the 26 jurisdictions with CHIK cases, 22 (85%) reported the presence of CHIKV vectors. Twelve viremic travelers returned to 6 states with CHIKV vectors. Of the 106 cases identified in 2006–2009, only 27 (25%) were reported to ArboNET, with a median of 122 days (range, 44–273 days) between illness onset and reporting.
Conclusions.
No locally acquired CHIK cases were identified. However, several viremic travelers returned to states with CHIKV vectors and presented a risk for local transmission. Incomplete and delayed reporting made ArboNET less useful. To minimize the risk of CHIKV spread in the United States, healthcare providers and public health officials should be educated about recognition, diagnosis, and reporting of CHIK cases.
St. Louis encephalitis (SLE) and West Nile (WN) flaviviruses are genetically closely related and cocirculate in the United States. Virus neutralization tests provide the most specific means for ...serodiagnosis of infections with these viruses. However, use of wild-type SLE and WN viral strains for laboratory testing is constrained by the biocontainment requirements. We constructed two highly attenuated yellow fever (YF) virus chimeras that contain the premembrane-envelope (prM-E) protein genes from the virulent MSI-7 (isolated in the United States) or the naturally attenuated CorAn9124 (Argentina) SLE strains. The YF/SLE (CorAn version) virus and the previously constructed YF/WN chimera were shown to specifically distinguish between confirmed human SLE and WN cases in a virus neutralization test using patient sera. These chimeras have the potential for use as diagnostic reagents and vaccines against SLE and WN.
To investigate the infection status and the spatial distribution of Tahyna virus infection among unknown fever cases in Xinjiang, China. Sera samples of unknown fever cases from Kashi in southern ...Xin-jiang and Yili in northern Xinjiang were tested against Tahyna virus by IFA. Partial positive cases were tested against Tahyna virus/Snowshoe hare virus/Inkoo virus parrelled. Finally, 742 sera samples of unknown fever cases were collected from Kashi, Southern Xinjiang in 2007-2008, the positive rate of IgM antibody against Tahyna virus was 5.3%, the positive rate of IgG antibody against Tahyna virus was 18.3%. 222 sera samples of unknown fever cases were collected from Yili, Northern Xinjiang in 2008, no positive case of IgM antibody against Tahyna was found. 10 cases showed antibody neutralization against Tahyna virus by plaque reduction neutralization test. Our results demonstrate that there is current infection and past infection of Tahyna virus among Southern Xinjiang residents.
Abstract
Following the recent discovery of Bourbon virus (BRBV) as a human pathogen, and the isolation of the virus from Amblyomma americanum (L.) collected near the location of a fatal human case, ...we undertook a series of experiments to assess the laboratory vector competence of this tick species for BRBV. Larval ticks were infected using an immersion technique, and transstadial transmission of virus to the nymphal and then to the adult stages was demonstrated. Transstadially infected nymphs transmitted virus to adult ticks at very high rates during cofeeding, indicating the presence of infectious virus in the saliva of engorging ticks. Vertical transmission by transstadially infected females to their progeny occurred, but at a low rate. Rabbits fed on by infected ticks of all active life stages developed high titers of antibody to the virus, demonstrating host exposure to BRBV antigens/live virus during tick blood feeding. These results demonstrate that A. americanum is a competent vector of BRBV and indicate that cofeeding could be critical for enzootic maintenance.
A kidney transplant patient without known tick exposure developed encephalitis 3 weeks after transplantation. During the transplant hospitalization, the patient had received a blood transfusion from ...an asymptomatic donor later discovered to have been infected with Powassan virus. Here, we describe a probable instance of transfusion-transmitted Powassan virus infection.
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