Background: Dengue is a growing problem both in its geographical spread and in its intensity, and yet current global distribution remains highly uncertain. Challenges in diagnosis and diagnostic methods as well as highly variable national health systems mean no single data source can reliably estimate the distribution of this disease. As such, there is a lack of agreement on national dengue status among international health organisations. Here we bring together all available information on dengue occurrence using a novel approach to produce an evidence consensus map of the disease range that highlights nations with an uncertain dengue status. Methods/Principal Findings: A baseline methodology was used to assess a range of evidence for each country. In regions where dengue status was uncertain, additional evidence types were included to either clarify dengue status or confirm that it is unknown at this time. An algorithm was developed that assesses evidence quality and consistency, giving each country an evidence consensus score. Using this approach, we were able to generate a contemporary global map of national-level dengue status that assigns a relative measure of certainty and identifies gaps in the available evidence. Conclusion: The map produced here provides a list of 128 countries for which there is good evidence of dengue occurrence, including 36 countries that have previously been classified as dengue-free by the World Health Organization and/or the US Centers for Disease Control. It also identifies disease surveillance needs, which we list in full. The disease extents and limits determined here using evidence consensus, marks the beginning of a five-year study to advance the mapping of dengue virus transmission and disease risk. Completion of this first step has allowed us to produce a preliminary estimate of population at risk with an upper bound of 3.97 billion people. This figure will be refined in future work.

/pdf/refining-the-global-spatial-limits-of-dengue-virus-f8emry0wk5.pdf

Refining the global spatial limits of dengue virus transmission by evidence-based consensus

Complement-fixation test reactions to eight viruses of the family Togaviridae were studied in 372 serum samples (157 rodents, 172 domestic animals, 43 humans) from Pakistan. Antibodies to each tested virus were detected. The highest over-all prevalence rates were for West Nile (WN) (7.8%), Japanese encephalitis (JE) (3.2%) and Zika (ZIKA) (2.4%) viruses, followed by Sindbis (SIN), Chikungunya (CHIK), Uganda S (UGS) and Royal Farm (RF) viruses (1.6 to 1.3%). One human serum (male, age 58 years) reacted with Dengue-1 (DEN) virus antigen (titre 1:32). Antibodies to each virus except RF were detected in human sera; antibodies to RF virus were detected only in rodent and domestic animal sera. The roles of rodents in the epidemiology of WN, JE and ZIKA viruses should be investigated. At least six of these eight viruses cause fevers in humans (fevers of unknown origin comprise about one third of the febrile episodes recorded in Pakistan).

A sero-epidemiological survey for certain arboviruses (Togaviridae) in Pakistan

West Nile (WN) fever is a mosquito-borne flavivirus transmitted in natural cycles between birds and mosquitoes, particularly Culex species mosquitoes.

The ecology and epidemiology of West Nile virus in Africa, Europe and Asia.

Background 
Dengue virus (DENV) infection is widespread and its disease burden has increased in past decades. However, little is known about the epidemiology of dengue in the Middle East and North Africa (MENA).


Methodology / Principal Findings 
Following Cochrane Collaboration guidelines and reporting our findings following PRISMA guidelines, we systematically reviewed available records across MENA describing dengue occurrence in humans (prevalence studies, incidence studies, and outbreak reports), occurrence of suitable vectors (Aedes aegypti and Aedes albopictus), and DENV vector infection rates. We identified 105 human prevalence measures in 13 of 24 MENA countries; 81 outbreaks reported from 9 countries from 1941–2015; and reports of Ae. aegypti and/or Ae. albopictus occurrence in 15 countries. The majority of seroprevalence studies were reported from the Red Sea region and Pakistan, with multiple studies indicating >20% DENV seroprevalence in general populations (median 25%, range 0–62%) in these subregions. Fifty percent of these studies were conducted prior to 1990. Multiple studies utilized assays susceptible to serologic cross-reactions and 5% of seroprevalence studies utilized viral neutralization testing. There was considerable heterogeneity in study design and outbreak reporting, as well as variability in subregional study coverage, study populations, and laboratory methods used for diagnosis.


Conclusions / Significance 
DENV seroprevalence in the MENA is high among some populations in the Red Sea region and Pakistan, while recent outbreaks in these subregions suggest increasing incidence of DENV which may be driven by a variety of ecologic and social factors. However, there is insufficient study coverage to draw conclusions about Aedes or DENV presence in multiple MENA countries. These findings illustrate the epidemiology of DENV in the MENA while revealing priorities for DENV surveillance and Aedes control.

/pdf/dengue-in-the-middle-east-and-north-africa-a-systematic-394ozea5fw.pdf

Dengue in the Middle East and North Africa: A Systematic Review.

Egypt has a unique geographical location connecting the three old-world continents Africa, Asia and Europe. It is the country with the highest population density in the Middle East, Northern Africa and the Mediterranean basin. This review summarizes the prevalence, reservoirs, sources of human infection and control regimes of common bacterial, parasitic and viral zoonoses in animals and humans in Egypt. There is a gap of knowledge conerning the epidemiology of zoonotic diseases at the human-animal interface in different localities in Egypt. Some zoonotic agents are "exotic" for Egypt (e.g., MERS-CoV and Crimean-Congo hemorrhagic fever virus), others are endemic (e.g., Brucellosis, Schistosomiasis and Avian influenza). Transboundary transmission of emerging pathogens from and to Egypt occurred via different routes, mainly importation/exportation of apparently healthy animals or migratory birds. Control of the infectious agents and multidrug resistant bacteria in the veterinary sector is on the frontline for infection control in humans. The implementation of control programs significantly decreased the prevalence of some zoonoses, such as schistosomiasis and fascioliasis, in some localities within the country. Sustainable awareness, education and training targeting groups at high risk (veterinarians, farmers, abattoir workers, nurses, etc.) are important to lessen the burden of zoonotic diseases among Egyptians. There is an urgent need for collaborative surveillance and intervention plans for the control of these diseases in Egypt.

A Comprehensive Review of Common Bacterial, Parasitic and Viral Zoonoses at the Human-Animal Interface in Egypt

A serologic survey was carried out to demonstrate the present distribution of antibodies to certain arboviruses in Egypt. An examination of serum specimens from 1,113 male university students from different localities of Egypt showed that West Nile, phlebotomus fever, and Sindbis viruses are endemic, having overall prevalence rates of 50%, 23%, and 6%. The geographic distribution of West Nile and Sindbis viruses was identical, and dissimilar to that of the ecologically different phlebotomus fever virus. The prevalence of West Nile and Sindbis viruses has decreased from that reported 10 to 15 years ago, whereas that of phlebotomus fever remained unchanged. No antibodies were detected to eastern equine encephalomyelitis, western equine encephalomyelitis, or Bunyamwera virus. Only four serum samples (0.3%) were positive for dengue 1 virus.

Abdel Halim Ibrahim

Papers

Prevalence of antibodies to arboviruses in Egypt. Results of a serologic survey among 1,113 university students.