Which of the following flavi virus is closely related to Russian spring summer encephalitis causing virus
**Core Concept**
The Russian spring-summer encephalitis (RSSV) is a tick-borne flavivirus that causes severe neurological disease in humans. The RSSV is transmitted primarily through the bite of infected ticks, and its clinical manifestations range from mild fever to severe encephalitis.
**Why the Correct Answer is Right**
The correct answer is related to the Russian spring-summer encephalitis virus because both viruses belong to the same serogroup, namely the tick-borne encephalitis virus (TBEV) complex. The TBEV complex includes several flaviviruses that are transmitted by ticks and cause neurological disease in humans. The RSSV is closely related to the Omsk hemorrhagic fever virus (OHFV) and the Kyasanur Forest disease virus (KFDV), all of which are part of the TBEV complex.
**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because the yellow fever virus (YFV) is a different flavivirus that is transmitted primarily through the bite of infected mosquitoes, not ticks.
**Option B:** This is incorrect because the dengue virus (DENV) is another distinct flavivirus that is also transmitted by mosquitoes, not ticks.
**Option C:** This is incorrect because the Zika virus (ZIKV) is a flavivirus that is primarily transmitted by mosquitoes, and is not closely related to the Russian spring-summer encephalitis virus.
**Clinical Pearl / High-Yield Fact**
It's essential to recognize that the TBEV complex includes several flaviviruses that are tick-borne and cause neurological disease in humans, making the correct identification of the serogroup crucial for diagnosis and treatment.
**Correct Answer:** D.