Concern over Zika virus outbreak: another alarming global threat

Zika and Flavivirus Shell Disorder: Virulence and Fetal Morbidity

Zika virus (ZIKV) was first discovered in 1947 in Africa. Since then, sporadic ZIKV infections of humans have been reported in Africa and Asia. For a long time, this virus was mostly unnoticed due to its mild symptoms and low fatality rates. However, during the 2015-2016 epidemic in Central and South America, when millions of people were infected, it was discovered that ZIKV causes microcephaly in the babies of mothers infected during pregnancy. An examination of the M and C proteins of the ZIKV shell using the disorder predictor PONDR VLXT revealed that the M protein contains relatively high disorder levels comparable only to those of the yellow fever virus (YFV). On the other hand, the disorder levels in the C protein are relatively low, which can account for the low case fatality rate (CFR) of this virus in contrast to the more virulent YFV, which is characterized by high disorder in its C protein. A larger variation was found in the percentage of intrinsic disorder (PID) in the C protein of various ZIKV strains. Strains of African lineage are characterized by higher PIDs. Using both in vivo and in vitro experiments, laboratories have also previously shown that strains of African origin have a greater potential to inflict higher fetal morbidity than do strains of Asian lineage, with dengue-2 virus (DENV-2) having the least potential. Strong correlations were found between the potential to inflict fetal morbidity and shell disorder in ZIKV (r² = 0.9) and DENV-2 (DENV-2 + ZIKV, r² = 0.8). A strong correlation between CFR and PID was also observed when ZIKV was included in an analysis of sets of shell proteins from a variety of flaviviruses (r² = 0.8). These observations have potential implications for antiviral vaccine development and for the design of cancer therapeutics in terms of developing therapeutic viruses that penetrate hard-to-reach organs.

Assessment of the Hepatitis C Surveillance System in Henan, China: 2014~2016

Objectives

To access the Hepatitis C (HepC) surveillance program in Henan, China, 2014~2016.

Methods

A total of 8,448 HepC-relevant cases were reviewed and this data was then inquired against the 6,147 archived HepC reports during the same time period. The performance of the HepC surveillance program was evaluated using parameters including Timely Reporting Rate (TRR), pairs of Report Sensitivity (RS)/Underreporting Rate (UR), and False Report Rate (FRR)/Predictive Value Positive (PVP). Longitudinal comparisons of report quality over the three examined years were conducted to determine the temporal trend of HepC surveillance accountability.

Results

All HepC reports were submitted within 24 hours post diagnosis, and TRR rates for all examined years remained at 100%. The RS rates significantly improved overtime for clinically diagnosed HepC cases (CDHC) (2014:60.32%, 2015:68.13%, and 2016:82.83%), whereas the RS for confirmed HepC cases (CHC) remained relatively constant (80.77%, 88.64%, and 85.82%). The FRR rates for CDHC and CHC in 2015~2016 were both approximately 30% but at 23.61% and 51.85%, respectively, in 2014.

Conclusions

The HepC surveillance system in Henan remains effective and consistent improvement in report accountability was observed over time. However, some issues concerning especially RS and PVP remained to be addressed for ensuring data accountsbility.

Health care providers' compliance with the notifiable diseases surveillance system in South Africa

Background

The optimal performance of a notifiable disease surveillance system (NDSS) is dependent on health care provider (HCP) compliance with communicable disease notification. HCP compliance ensures appropriate investigation and control measures by relevant health care authorities. This study examines the compliance of HCPs with the NDSS in South Africa and factors associated with their compliance.

Methods

A cross-sectional survey was carried out in three randomly selected provinces. We stratified by type of facility, and recruited clusters of HCPs on survey day to participate. All consenting HCPs in the randomly selected health care facilities on the day of the survey, completed a questionnaire that elicited information on socio-demographic characteristics and notification practices. The data were analysed using STATA^® 14, using the identifiers for stratum and cluster as well as the calculated sampling weights.

Results

The study found that 58% of 919 HCPs diagnosed a notifiable disease in the year preceding the survey. The majority of these professionals (92%) indicated that they had reported the disease, but only 51% of those notified the disease/s correctly to the Department of Health. Paediatricians were less likely to notify correctly (OR 0.01, 95% CI 0.00–0.12, p = 0.001). The factors that influenced notification were HCPs perceptions of workload (OR 0.84, 95% CI 0.70–0.99, p = 0.043) and that notification data are not useful (OR 0.84, 95% CI 0.71–0.99, p = 0.040). The study found no association between correct notification and HCPs’ willingness to notify, experience or training on the NDSS, understanding of the purpose of the NDSS, knowledge of what to notify, or perception of feedback given.

Conclusions

The compliance of HCPs in South Africa with the NDSS is suboptimal. In light of the important role of HCPs in the effective functioning of the NDSS, information on NDSS usefulness and guidelines on correct notification procedures are needed to increase their compliance.

Global risk mapping for major diseases transmitted by Aedes aegypti and Aedes albopictus

OBJECTIVES

The objective of this study was to map the global risk of the major arboviral diseases transmitted by Aedes aegypti and Aedes albopictus by identifying areas where the diseases are reported, either through active transmission or travel-related outbreaks, as well as areas where the diseases are not currently reported but are nonetheless suitable for the vector.

METHODS

Data relating to five arboviral diseases (Zika, dengue fever, chikungunya, yellow fever, and Rift Valley fever (RVF)) were extracted from some of the largest contemporary databases and paired with data on the known distribution of their vectors, A. aegypti and A. albopictus. The disease occurrence data for the selected diseases were compiled from literature dating as far back as 1952 to as recent as 2017. The resulting datasets were aggregated at the country level, except in the case of the USA, where state-level data were used. Spatial analysis was used to process the data and to develop risk maps.

RESULTS

Out of the 250 countries/territories considered, 215 (86%) are potentially suitable for the survival and establishment of A. aegypti and/or A. albopictus. A. albopictus has suitability foci in 197 countries/territories, while there are 188 that are suitable for A. aegypti. There is considerable variation in the suitability range among countries/territories, but many of the tropical regions of the world provide high suitability over extensive areas. Globally, 146 (58.4%) countries/territories reported at least one arboviral disease, while 123 (49.2%) reported more than one of the above diseases. The overall numbers of countries/territories reporting autochthonous vector-borne occurrences of Zika, dengue, chikungunya, yellow fever, and RVF, were 85, 111, 106, 43, and 39, respectively.

CONCLUSIONS

With 215 countries/territories potentially suitable for the most important arboviral disease vectors and more than half of these reporting cases, arboviral diseases are indeed a global public health threat. The increasing proportion of reports that include multiple arboviral diseases highlights the expanding range of their common transmission vectors. The shared features of these arboviral diseases should motivate efforts to combine interventions against these diseases.

Flavivirus and Filovirus EvoPrinters: New alignment tools for the comparative analysis of viral evolution

Background

Flavivirus and Filovirus infections are serious epidemic threats to human populations. Multi-genome comparative analysis of these evolving pathogens affords a view of their essential, conserved sequence elements as well as progressive evolutionary changes. While phylogenetic analysis has yielded important insights, the growing number of available genomic sequences makes comparisons between hundreds of viral strains challenging. We report here a new approach for the comparative analysis of these hemorrhagic fever viruses that can superimpose an unlimited number of one-on-one alignments to identify important features within genomes of interest.

Methodology/Principal finding

We have adapted EvoPrinter alignment algorithms for the rapid comparative analysis of Flavivirus or Filovirus sequences including Zika and Ebola strains. The user can input a full genome or partial viral sequence and then view either individual comparisons or generate color-coded readouts that superimpose hundreds of one-on-one alignments to identify unique or shared identity SNPs that reveal ancestral relationships between strains. The user can also opt to select a database genome in order to access a library of pre-aligned genomes of either 1,094 Flaviviruses or 460 Filoviruses for rapid comparative analysis with all database entries or a select subset. Using EvoPrinter search and alignment programs, we show the following: 1) superimposing alignment data from many related strains identifies lineage identity SNPs, which enable the assessment of sublineage complexity within viral outbreaks; 2) whole-genome SNP profile screens uncover novel Dengue2 and Zika recombinant strains and their parental lineages; 3) differential SNP profiling identifies host cell A-to-I hyper-editing within Ebola and Marburg viruses, and 4) hundreds of superimposed one-on-one Ebola genome alignments highlight ultra-conserved regulatory sequences, invariant amino acid codons and evolutionarily variable protein-encoding domains within a single genome.

Conclusions/Significance

EvoPrinter allows for the assessment of lineage complexity within Flavivirus or Filovirus outbreaks, identification of recombinant strains, highlights sequences that have undergone host cell A-to-I editing, and identifies unique input and database SNPs within highly conserved sequences. EvoPrinter’s ability to superimpose alignment data from hundreds of strains onto a single genome has allowed us to identify unique Zika virus sublineages that are currently spreading in South, Central and North America, the Caribbean, and in China. This new set of integrated alignment programs should serve as a useful addition to existing tools for the comparative analysis of these viruses.

Flaviviruses, including Zika and Dengue viruses, and Filoviruses, including Ebola and Marburg viruses, are significant global public health threats. Genetic surveillance of viral isolates provides important insights into the origin of outbreaks, reveals lineage heterogeneity and diversification, and facilitates identification of novel recombinant strains and host cell modified viral genomes. We report the development of EvoPrinter, a web-accessed alignment tool for the rapid comparative analysis of viral genomes. EvoPrinter superimposes alignment data from multiple pairwise comparisons onto a single reference sequence of interest, to reveal both similarities and differences detected in hundreds of selected viral isolates. Evoprinter databases provide easy access to hundreds of non-redundant Flavivirus and Filovirus genomes. allowing the user to distinguish between sublineage identity SNPs and unique strain-specific SNPs, thus facilitating analysis of the history of viral diversification during an epidemic. EvoPrinter also proves useful in identifying recombinant strains and their parental lineages and detecting host-cell genomic editing. EvoPrinter should serve as a useful addition to existing tools for the comparative analysis of these viruses.

Comparing laboratory surveillance with the notifiable diseases surveillance system in South Africa

OBJECTIVE

The aim of this study was to compare laboratory surveillance with the notifiable diseases surveillance system (NDSS) in South Africa.

METHODS

Data on three tracer notifiable diseases - measles, meningococcal meningitis, and typhoid - were compared to assess data quality, stability, representativeness, sensitivity and positive predictive value (PPV), using the Wilcoxon and Chi-square tests, at the 5% significance level.

RESULTS

For all three diseases, fewer cases were notified than confirmed in the laboratory. Completeness for the laboratory system was higher for measles (63% vs. 47%, p<0.001) and meningococcal meningitis (63% vs. 57%, p<0.001), but not for typhoid (60% vs. 63%, p=0.082). Stability was higher for the laboratory (all 100%) compared to notified measles (24%, p<0.001), meningococcal meningitis (74%, p<0.001), and typhoid (36%, p<0.001). Representativeness was also higher for the laboratory (all 100%) than for notified measles (67%, p=0.058), meningococcal meningitis (56%, p=0.023), and typhoid (44%, p=0.009). The sensitivity of the NDSS was 50%, 98%, and 93%, and the PPV was 20%, 57%, and 81% for measles, meningococcal meningitis, and typhoid, respectively.

CONCLUSIONS

Compared to laboratory surveillance, the NDSS performed poorly on most system attributes. Revitalization of the NDSS in South Africa is recommended to address the completeness, stability, and representativeness of the system.

Prevention and Control Strategies to Counter ZIKA Epidemic

ZIKA virus (ZIKA) has now become a global phenomenon. Since 2007, evidence of ZIKA transmission has been reported over 72 countries and territories. The transmission of ZIKA has made World Health Organization to categorize the situation under the ambit of a health emergency. This situation is serious because there appears to be a highly tangible link between infection during pregnancy and the occurrence of microcephaly and Guillain–Barré syndrome. In the context of this emergency situation, this review article intends to discuss the prevention and control strategies such as avoiding travel to infected area, being careful from mosquito bites, take precautions to reduce the risk of sexual transmission, and seek medical care for any acute illness with rash or fever. This review is an attempt to analyze the results of those campaigns, keeping in view the variables and constants that affect any such measures. Furthermore, this article will suggest proactive measures that can be employed to effectively combat the epidemic transmission of the ZIKA.