The mosquito-borne Zika virus (ZIKV) is one of the most feared viruses for pregnant women. Recent statistics justify this fear: Infants born to mothers infected with ZIKV during pregnancy face a risk of up to 42 percent of developing birth defects, including microcephaly (an abnormally small head and decreased brain volume). What do we know about how ZIKV causes damage to the developing brain?Several lines of evidence suggest that after ZIKV is transmitted to a pregnant woman via the bite of an infected mosquito, the virus then directly infects cells of the placenta, gaining access to the fetal brain. Following attachment, the virion would most likely enter the placental cellby:a. insertion via the mosquito's mouthpartsb. endocytosisc. degrading the cell wall with lysozymed. injection through a hollow, needle-like protein structure

Verified step by step guidance

1. Understand the nature of Zika virus (ZIKV) and its transmission method. ZIKV is transmitted through the bite of an infected mosquito and can infect pregnant women.
2. Recognize the target of ZIKV after transmission. Once a pregnant woman is infected, the virus can target the placenta, which is crucial for providing nutrients and oxygen to the developing fetus.
3. Identify the potential entry mechanisms of ZIKV into placental cells. The virus needs to enter these cells to reach the fetal environment.
4. Evaluate the listed options for how ZIKV might enter placental cells: a) insertion via the mosquito's mouthparts, b) endocytosis, c) degrading the cell wall with lysozyme, d) injection through a hollow, needle-like protein structure.
5. Consider the typical mechanisms of viral entry into host cells, focusing on those relevant to viruses similar to ZIKV. Viruses often enter cells through processes like endocytosis, where the cell membrane engulfs the virus.

Key Concepts

Zika Virus Transmission

Zika virus is primarily transmitted to humans through the bite of infected Aedes mosquitoes. Once in the bloodstream, the virus can cross the placenta, leading to potential infection of the developing fetus. Understanding this transmission route is crucial for grasping how the virus can affect pregnancy and fetal development.

Endocytosis

Endocytosis is a cellular process where cells engulf external substances, allowing them to enter the cell. In the context of Zika virus infection, the virus can utilize endocytosis to penetrate placental cells, facilitating its access to the fetal brain. This mechanism is vital for understanding how viruses exploit cellular pathways to infect host tissues.

Microcephaly and Birth Defects

Microcephaly is a condition characterized by an abnormally small head and reduced brain size, often resulting from developmental disruptions during pregnancy. Zika virus infection in pregnant women has been linked to an increased risk of microcephaly and other birth defects, highlighting the importance of studying the virus's effects on fetal brain development and the underlying mechanisms of damage.