A pandemic risk assessment of middle east respiratory syndrome coronavirus (MERS-CoV) in Saudi Arabia

Eifan, Saleh A.; Nour, Islam; Hanif, Atif; Zamzam, Abdelrahman M.M.; AlJohani, Sameera Mohammed

The CI calculated for the reproductive number was found varying considerably across the studied period in the regions undergone sensitivity analysis, beginning with a wider CI and ending with a significantly narrower CI. Reduced CI in terms of time indicated more related secondary cases rather than sporadic case incidences. The current data suggested the less likelihood of external sources as zoonotic intermediates to participate in MERS-CoV spread dynamics. Current finding contradicted the results of Paletto, et al. (2014) who stated that the CI for the estimated R was steady along the variations in the data interpretation. The discrepancy might be owing to the fact that the current study was restricted to MERS-CoV cases in Saudi Arabia rather than the Middle East region. Moreover, the variation of the baseline scenario estimates (up to R = 0.97) with sensitivity analysis values (up to R = 1.12) were interpreted by the insignificant contribution of zoonotic transmissions to the MERS-CoV outbreak. However, the impact of sporadic cases on the epidemic level of MERS-CoV over the threshold limit (R > 1) was observed in both central and western regions. The finding of current study supported the data from previous study that animal contact was an uncommon cause for MERS-CoV in the detected cases . Some studies reported mild MERS cases and other reported a broad spectrum of clinical disease (Assiri et al., 2013) . The present study might have a selection bias towards symptomatic cases. However, mild/asymptomatic cases, if detected, might lead to different spread patterns of MERS-CoV. Screening programs for earlier detection of MERS-CoV silent infection could relate the sporadic cases to their index cases, which could affect directly the estimation of the probable waves of MERS-CoV infection (Widagdo et al., 2017) . Moreover, it could aid in mapping of the primary cases destination as well as the high MERS-CoV incidence regions. Hence, traceability of MERS-CoV could be enhanced that might support the convenient control measures. The second possibility is that these asymptomatic patients, if observed, could reveal the factors other than interhuman transmission that affect the MERS-CoV spread pattern, since some previous studies reported dromedary camels as a potential intermediate host for MERS-CoV (Haagmans et al., 2014; Raj et al., 2014a,b) .