Lack of Zika Virus and Other Recognized Flaviviruses among the Mosquito Vectors during and Post the Hajj Mass Gathering.

Saber Yezli,Kingsley Bieh,Yara Yassin,Sameer Almahmoodi,Mohammed Alzahrani,Abdiasiis Omar,Muhammad Yasir,Afnan Almazrua,Anas Khan,Turki Bafaraj,Abuzaid Abuzaid,Esam I Azhar,Tagreed Al-Subhi,Norah Othman,Yousif Elamin,Hussam Alzahrani,Abdelmohsin Abdoon,Hassen Alzahrani,Badriah Alotaibi

doi:10.3390/ijerph18126275

Abstract

Makkah city, Kingdom of Saudi Arabia (KSA), contains many of the world’s mosquito vectors of parasitic and arboviral disease and is the site of the Hajj mass gathering. As such there is a risk of exportation and globalization of vector-borne viruses, including the re-emerging Zika virus (ZIKV). There was international concern regarding the introduction of ZIKV to KSA and potential international spread of the virus following the 2016 Hajj which took place few days after the Rio summer Olympics at the height of the ZIKV pandemic. We aimed to detect flaviviruses, including ZIKV, circulating among mosquito hosts in the city of Makkah during and post the 2016 Hajj pilgrimage. Mosquitos (adults and larvae) were sampled from 15 sites in Makkah city during and post the 2016 Hajj and identified to species by morphological keys. Mosquitos were pooled according to date of collection, location, and species. A Pan-Flaviviruses RT-PCR assay that enables identification of 51 flaviviruses species and three tentative species was used to detect flavivirus RNA directly from mosquito homogenates. Between the 10 September and 6 October 2016, 9412 female mosquitos were collected. Of these, 81.3% were Aedes aegypti, 18.6% were Culex species, and 0.1% were Anopheles species. Of the total 493 mosquito pools generated, 242 (49%) were positive by the Pan-Flaviviruses primer set. Sequence analysis revealed that none of the mosquitos carried a pathogenic flavivirus, including ZIKV, but were infected with a novel insect-specific flavivirus. We found no pathogenic flaviviruses circulating in Makkah city during and post the 2016 Hajj and no evidence of introduction of ZIKV through the pilgrimage. Enhanced vector-borne diseases surveillance, prevention, and control are crucial in KSA especially during international mass gatherings such as the annual Hajj to prevent outbreaks and the spread of viruses with epidemic and pandemic potentials.

Highlights

IntroductionFlavivirus is a genus of positive-sense RNA viruses with similar genomic organizations but fundamental differences in their natural host ranges and transmission cycles [1].Most flaviviruses are horizontally transmitted between hematophagous arthropods (i.e., mosquitoes and ticks) and vertebrate hosts in which infections range from asymptomatic to severe or fatal hemorrhagic fever or neurological disease [2]
Flavivirus is a genus of positive-sense RNA viruses with similar genomic organizations but fundamental differences in their natural host ranges and transmission cycles [1].Most flaviviruses are horizontally transmitted between hematophagous arthropods and vertebrate hosts in which infections range from asymptomatic to severe or fatal hemorrhagic fever or neurological disease [2]
There was evidence that the mosquito vector was infected with a probably novel insect flavivirus. These results suggest that Zika virus (ZIKV) was not circulating in Makkah during the study period and that there is no evidence that ZIKV was introduced to Kingdom of Saudi Arabia (KSA) through the 2016 Hajj mass gathering

Summary

Introduction

Flavivirus is a genus of positive-sense RNA viruses with similar genomic organizations but fundamental differences in their natural host ranges and transmission cycles [1].Most flaviviruses are horizontally transmitted between hematophagous arthropods (i.e., mosquitoes and ticks) and vertebrate hosts in which infections range from asymptomatic to severe or fatal hemorrhagic fever or neurological disease [2]. Important human pathogens include the mosquito-borne viruses; yellow fever virus (YFV), Zika virus (ZIKV), dengue virus (DENV), Japanese encephalitis virus (JEV), and West Nile virus (WNV)), and tickborne encephalitis virus (TBEV). These pathogens have plagued mankind, accounting for millions of morbidity and mortality worldwide, and potentially could affect non-endemic areas already colonized by the vectors [3,4]. Given that Saudi Arabia is visited by millions of travelers each year, including up to 10 million religious pilgrims during the Hajj and Umrah mass gatherings, the risk of outbreaks and globalization of mosquito-borne flaviviruses, including DENV and ZIKV, is significant in KSA [8,9]. While most ZIKV infections are asymptomatic or present mild clinical disease, ZIKV infection during pregnancy can cause congenital microcephaly and other brain defects; Guillain-Barre syndrome, stillbirth, and miscarriages [10]

Objectives

Results

Discussion

Conclusion