The potentiality of Culex pipiens (Diptera: Culicidae) complex holobiont in transmitting the hepatitis C virus (HCV) with the aid of bacterial microbiota in the midgut

Background

The possibility of considering Culex pipiens (Cx. pipiens) as a vector for transmitting the hepatitis C virus (HCV) is controversial and needs further investigation. This work aimed to detect the possibility of transmission of the hepatitis C virus by Cx. pipiens and the role of the bacterial microbiota in their midgut.

Main body

Two groups of symbiotic and aposymbiotic of female Cx. pipiens were infected with the hepatitis C virus using an artificial feeding membrane technique. The viral load was detected in the head region for up to 60 min in the infected symbiotic group and 90 min in the aposymbiotic group. The midgut region can harbor the virus for 5 days after feeding. The absence of gut microbiota increases the potentiality of ten females to carry high titer of infective dose (1.2 × 10⁶ IU/ml) of HCV genotype 4a for 6 days. The bacterial midgut microbiota appears to play a significant role in the transmission of HCV. On the other hand, HCV was not detected in the salivary glands of either symbiotic or aposymbiotic mosquitoes during the detection period. Cx. pipiens can transmit HCV from infected female adult mosquitoes to HCV-negative human blood in vitro. The biological parameters were survival rate, blood feeding, oviposition, hatchability rates, and mean digestion period of Cx. pipiens after infection with HCV showed significant changes. Moreover, an ex vivo assay demonstrated that HCV-infected mosquitoes could transmit the virus RNA into healthy blood.

Conclusion

The results suggested that the mosquitoes’ mechanical transmission of HCV was reasonable. In addition, the mosquito microbiome played a significant role in determining the potentiality of mosquitoes as a vector for disseminating HCV infections.

Graphic abstract