Sero-epidemiological study on Dengue fever virus in humans and camels at Upper Egypt

Abstract

Background and Aim: Dengue fever (DF) is an important mosquito-borne viral zoonosis affecting over 100 countries worldwide and putting about 3.9 billion people at risk of infection. The disease has re-emerged in Egypt since 2011; however, there is a paucity of recent epidemiological data available. Therefore, in this study, we employed a cross-sectional study to determine DF prevalence in humans and camels in Asyut and Sohag Governorates, Egypt, during 2019. Materials and Methods: A total of 91 humans and a similar number of dromedary camels were utilized in this study. Sera were obtained and analyzed for the presence of specific antibodies against DF virus using enzyme-linked immunosorbent assay. Related epidemiological data affecting the disease spread in humans and camels were recorded and statistically analyzed. Results: The seroprevalence of DF in humans and camels was 12.09% and 3.3%, respectively. The disease varied significantly by the species examined as humans were found to be at a higher risk of acquiring the infection compared to camels. Nearly equal odds of exposure (odds ratio [OR]) were seen in the individuals with close contact with camels compared to those without; however, individuals exposed to mosquitoes were at approximately 3 times higher risk of infection (OR=2.95 [95% confidence interval [CI], 0.73-11.93]) compared to individuals who were not exposed to mosquitoes (OR=0.033 [95% CI, 0.084-1.37]). Interestingly, DF seropositivity in camels was significantly related to the presence or absence of symptoms within 2 weeks before sampling (p=0.02) where symptomatic animals had higher odds of exposure (OR=19.51 [95%, 0.97- 392.3]) compared to asymptomatic ones (OR=0.05 [95%, 0.002-1.03]). Conclusion: The current study reports the presence of specific antibodies against dengue virus (DENV) in humans residing within Asyut and Sohag Governorates, Egypt. Furthermore, it provides the first serological evidence of DENV circulation in camels which is alarming. A more comprehensive study is needed; however, this baseline investigation underscores the urgent need for increasing awareness among people residing in the area as well as application of the appropriate mosquito control measures to avoid further spread of the disease.

Epidemiology of Mosquito-Borne Viruses in Egypt: A Systematic Review

“…This gap in the literature has existed for half a century. In Sohag and Assiut in 2019, the positive rates of DENV antibodies in the general population aged <21 years, 21 to 40 years, and >40 years old were 25%, 11.32%, and 10%, respectively, and 3.30% in local camels [ 34 ].…”

“…Multiple studies on DENV seroprevalence in the Red Sea region and Pakistan have indicated a rate of more than 20% DENV seroprevalence in the general population [ 23 ]. Moreover, DENV has been prevalent in camels in Egypt, with an antibody positivity rate of 3.3% [ 34 ], implying that camels may serve as reservoirs of DENV. The seropositivity rate for DENV was 47.6% among residents from El-Gadarif State, Sudan [ 68 ].…”

Assessment of dengue virus threat to blood safety and community health: A single center study in northern Egypt

“…However, the prevalence among the general population in some cities in Upper Egypt, where outbreaks of dengue have been previously reported, was found to be 12.09%. 16 Using an alpha error = 5% and a precision = 3%, the minimum required sample size was found to be 454, and we eventually enrolled 500 participants. The sample size was calculated using Epi-Info software (version 7).…”

The Constant Threat of Zoonotic and Vector-Borne Emerging Tropical Diseases: Living on the Edge

“…As was expected, coinfections between tropical pathogens and COVID-19 are also now increasingly being reported, especially with dengue (30). Dengue affects over 100 countries worldwide and puts about 2.5-3.9 billion people at risk of infection (113,114). Within the next century, nearly a billion people are at risk of exposure to virus transmission by both main Aedes spp., Ae.…”