Judul: Seroprevalence of Chikungunya and The Risk of Transmission Transmitted Among Blood Donors In Sulawesi-Indonesia
Abstrak: Chikungunya (CHIK) is an arthritogenic alphavirus in the Togaviridae family of arboviruses with an enveloped RNA containing a positive single-stranded 11.8 kb genome. Transmission occurs through the bite of infected Aedes mosquitoes, which are commonly found in tropical and temperate regions. Primary vertebrate hosts include monkeys and humans, in whom this virus replicates efficiently (Diallo et al. 1999). Chikungunya virus (CHIKV) is known for causing acute illness, manifesting with fever, rash, and arthralgia known as Chikungunya fever (Horwood dan Buchy 2015). Despite the high number of Chikungunya cases in Indonesia, comprehensive data are lacking in CHIKV seroprevalence. Previous studies reported the median seroprevalence of anti-CHIKV antibodies in all situations 18.5%, ranging from 0.0 – 73.% (Harapan et al., 2019). However, the gap in epidemiological data of CHIKV in many regions of Indonesia including Sulawesi, is noteworthy. The objective of this study was to determine the seroprevalence of CHIKV infection among healthy individuals from North and South Sulawesi using archive samples. Additionally, an asymptomatic course of CHIKV infection and the high pre-symptomatic viral load as 108pfu/mL (Appassakij et al. 2013) suggest that the infection can threaten blood transfusion safety. Evidence of CHIKV infection among blood donors (Simmons et al. 2016) indicates transfusion-transmitted is probable, although it has not been documented (Petersen dan Epstein 2014). Our study also aimed to test the archive blood donor specimens from North Sulawesi for CHIKV IgM and viremia to determine blood safety in endemic areas. Samples were screened for anti-CHIKV IgG antibodies to determine exposure to CHIKV using an in-house IgG ELISA as previously described (Kosasih et al. 2013) with minor modifications. CHIKV IgM, a marker for recent infection and endemicity, was tested in 303 samples randomly selected from IgG-positive samples using a Euroimmun anti-CHIKV IgM ELISA kit (Luebeck, Germany) following the manufacturer’s instructions. CHIKV RNA detection was carried out using one-step-qRT-PCR. The data generated were analyzed with IBM-SPSS v20 (IBM Corporation, USA). Chi-square (χ2) test to determine significant differences between categorical variables, and a p-value less than 0.05 was considered statistically significant. As many as 1092 serum and plasma samples were analyzed, with CHIK IgG seropositivity at 53.48% (584/1092). The results also show a statistically significant difference in the seropositive rates based on gender (58.8% male and 48.5% female) and region (53.9% South Sulawesi versus 48.7% North Sulawesi). Seropositivity increased with age; approximately half of adults between their 40s and 60s had seroconverted. Most of the participants, 304 (27.8%), were between 21-30 years. The age groups with the least participants were those >60 years and <20 years, with 93 participants each (8.5%), followed by the 51–60-years age group with 142 (13.0%) participants. In addition to IgG, the overall anti-CHIKV IgM seropositivity comprised 12.9% (39/303). A Chi-square analysis shows a statistical significance of anti-CHIKV IgM seropositivity based on gender and region with p-values (p=0.047 and p=0.038, respectively). On the contrary, there was no significant difference in anti-CHIK IgM based on age. The age group with the most participants was the 21-30 years with 19.3% (16/83), while those with the least participants were those >60 years. The current study
Keyword: Chikungunya, Serosurvey, Sulawesi, Blood donors, ELISA, qRT-PCR.