Biology subjects

Black, A.

Publications and source records attributed to Black, A..

4 recordsLinked to original sources

bioRxiv2018

HIV-Attributed Causes of Death in the Medical Ward at the Chris Hani Baragwanath Hospital, South Africa

BackgroundThere are sparse data in Africa on the association between HIV infection and deaths from underlying medical conditions. Using records from the Chris Hani Baragwanath Hospital (CHBH) in Soweto, South Africa, we determined mortality from medical conditions associated with HIV.\n\nMethodsFrom January 2006 to December 2009 AB collected data on 15,725 deaths including age, sex, day of admittance and death, HIV status, ART initiation and CD4+ cell counts and reviewed the underlying cause of death using medical notes. Conditions known to be associated with HIV were cases; conditions not associated with HIV were controls. We calculate the HIV odds-ratios for cases relative to controls and HIV-attributable deaths as the fraction of those with each condition, the disease-attributable fraction (DA), and as the fraction of all deaths, the population-attributable fraction (PAF).\n\nInterpretationThe high prevalence of HIV among those that died in the medical wards at the CHBH, especially in those below the age of 50 years, demonstrates the impact of the HIV-epidemic on adult mortality and hospital services and the extent to which early antiretroviral treatment would have reduced the burden of both. Of the deaths included in the analysis the prevalence of HIV was 61% and the prevalence of AIDS related conditions was 69%. The HIV-attributable fraction was 36% in the whole sample and 60% in those that were HIV-positive. Cryptococcosis, Kaposis sarcoma and Pneumocystis jeroveci are highly predictive of HIV while TB, gastroenteritis and anaemia are very strongly associated with HIV. The greatest number of deaths attributable to HIV was among those dying of TB or of other respiratory conditions.\n\nFundingNo funding was received for this study.

epidemiology↗

bioRxiv2017

Genetic characterization of the Zika virus epidemic in the US Virgin Islands

Here we release draft genome sequences of Zika virus (ZIKV) that were sequenced from PCR-positive diagnostic specimens collected by the United States Virgin Islands Department of Health (USVI DoH) as part of their ongoing response to the ZIKV outbreak. We will use these sequences to conduct a genomic epidemiological study of ZIKV transmission in the USVI. We are releasing these genomes in the hope that they are useful for those individuals involved in the public health response to ZIKV and to other groups working to understand Zika virus transmission and evolution.

epidemiology↗

bioRxiv2017

Epidemic establishment and cryptic transmission of Zika virus in Brazil and the Americas

Zika virus (ZIKV) transmission in the Americas was first confirmed in May 2015 in Northeast Brazil1. Brazil has the highest number of reported ZIKV cases worldwide (>200,000 by 24 Dec 20162) as well as the greatest number of cases associated with microcephaly and other birth defects (2,366 confirmed cases by 31 Dec 20162). Following the initial detection of ZIKV in Brazil, 47 countries and territories in the Americas have reported local ZIKV transmission, with 22 of these reporting ZIKV-associated severe disease3. Yet the origin and epidemic history of ZIKV in Brazil and the Americas remain poorly understood, despite the value of such information for interpreting past trends in reported microcephaly. To address this we generated 53 complete or partial ZIKV genomes, mostly from Brazil, including data generated by the ZiBRA project - a mobile genomics lab that travelled across Northeast Brazil in 2016. One sequence represents the earliest confirmed ZIKV infection in Brazil. Joint analyses of viral genomes with ecological and epidemiological data estimate that the ZIKV epidemic first became established in NE Brazil by March 2014 and likely disseminated from there, both nationally and internationally, before the first detection of ZIKV in the Americas. Estimated dates of the international spread of ZIKV from Brazil coincide with periods of high vector suitability in recipient regions and indicate the duration of pre-detection cryptic transmission in those regions. NE Brazils role in the establishment of ZIKV in the Americas is further supported by geographic analysis of ZIKV transmission potential and by estimates of the virus basic reproduction number.\n\nOne Sentence SummaryVirus genomes reveal the establishment of Zika virus in Northeast Brazil and the Americas, and provide an appropriate timeframe for baseline (pre-Zika) microcephaly in different regions.

genomics↗

bioRxiv2017

Multiplex PCR method for MinION and Illumina sequencing of Zika and other virus genomes directly from clinical samples

Genome sequencing has become a powerful tool for studying emerging infectious diseases; however, genome sequencing directly from clinical samples without isolation remains challenging for viruses such as Zika, where metagenomic sequencing methods may generate insufficient numbers of viral reads. Here we present a protocol for generating coding-sequence complete genomes comprising an online primer design tool, a novel multiplex PCR enrichment protocol, optimised library preparation methods for the portable MinION sequencer (Oxford Nanopore Technologies) and the Illumina range of instruments, and a bioinformatics pipeline for generating consensus sequences. The MinION protocol does not require an internet connection for analysis, making it suitable for field applications with limited connectivity. Our method relies on multiplex PCR for targeted enrichment of viral genomes from samples containing as few as 50 genome copies per reaction. Viral consensus sequences can be achieved starting with clinical samples in 1-2 days following a simple laboratory workflow. This method has been successfully used by several groups studying Zika virus evolution and is facilitating an understanding of the spread of the virus in the Americas.

genomics↗