Association Between Norovirus infection and TLR7 Gene Polymorphism in Iraqi Patients with Gastroenteritis

Abstract

Background: The gastroenteritis disease remains a global public health problem and human Noroviruses persist a cause of gastroenteritis. Noroviruses are highly contagious. They commonly spread through food or water that is contaminated during preparation or through contaminated surfaces. Noroviruses can also spread through close contact with a person who has norovirus infection. Objectives: To determine the rate of human Norovirus infections genome and the role of TLR-7 polymorphism in childhood Iraqi patients with gastroenteritis. Patients and methods: Case control study was carried out on 150 children and infant aged between (6-122 months) with gastroenteritis who attended the middle Euphrates hospitals for Maternity and Children as well as private laboratories, during the period from February 2021 till September 2021. Stool swabs, and blood samples were collected from each participant and stored as frozen at -70 °C to RNA extraction Norovirus genome and TLR-7 genome by using qReal Time PCR and Conventional PCR test, respectively. Results: The mean of age in patients with gastroenteritis was (43.56 months) while the control group (40.6 months) , also we found the infection in male more than female in percentage 58% for male and 42% for female. The rate of human Norovirus infection according to the quantitative real time PCR was 37.6% (29 out of 77) while the negative result was 62.4 % (48 out of 77). The present results indicated the presence of four nucleic acid variants in the investigated samples, namely 56G>A, 147A>T, 231C>T, and 288T>C. Results from the direct nucleic acid translation of the 56G>A indicated that this variant showed a missense effect on the protein, namely p.6S>N. The results of conventional polymerase chain reaction for TLR-7 for detection the relation with the severity of virus demonstrated that only 30% (45 out of 150) was positive for TLR-7 while the negative result was 70% (105 out of 150). The results showed that DNA polymorphism distribution were DNA polymorphism distributions according to CA ; AT ; TA and GA genotypes of TLR-7 polymorphism were respectively 62.2% (28 out of 45 cases) ; 31.1% (14 out of 45 cases); 6.7% (3 out of 45 cases) and 0% (0 out of 45 cases) in the GE patient group and was found GA genotype 100 % (5 out of 5 cases) in the control group. Conclusion: : The genome of the human norovirus genome appears to play a major role in gastroenteritis among infants and children, and TLR-7 has an important role in detecting norovirus severity among infected individuals.