Which is not true about Yellow fever
**Core Concept**
Yellow fever is a viral disease caused by the yellow fever virus (YFV), transmitted primarily through the bite of an infected Aedes mosquito. The disease is endemic in certain regions of Africa and South America, with a high mortality rate if left untreated.
**Why the Correct Answer is Right**
The yellow fever virus is a flavivirus that replicates in the liver, leading to a severe inflammatory response and necrosis of liver cells. This results in the characteristic symptoms of yellow fever, including fever, jaundice, and hemorrhaging. The virus is transmitted through the bite of an infected Aedes mosquito, which is why vector control measures are crucial in preventing the spread of the disease.
**Why Each Wrong Option is Incorrect**
**Option A:** Yellow fever is caused by a bacterial infection. Incorrect because yellow fever is a viral disease caused by the yellow fever virus.
**Option B:** Yellow fever is transmitted through direct contact with infected animals. Incorrect because yellow fever is primarily transmitted through the bite of an infected Aedes mosquito.
**Option C:** Yellow fever is a disease of the respiratory system. Incorrect because yellow fever primarily affects the liver, causing liver cell necrosis and jaundice.
**Clinical Pearl / High-Yield Fact**
The yellow fever vaccine is a live attenuated vaccine that provides lifelong immunity against the disease. It is essential for travelers to endemic areas and is recommended by the World Health Organization (WHO) for individuals traveling to or living in areas where yellow fever is endemic.
**Correct Answer:** Not provided, please provide the options for the question.