**13. Diagnosis of YF**

Clinical diagnosis of yellow fever is possible when the pathognomonic features of biphasic/ triphasic acute illness and typical clinical features occur in unvaccinated individuals with a compatible exposure history. Unfortunately, these features are present only in a minority of patients [67]. Laboratory confirmation of YF is pivotal to diagnosis, but unfortunately re‐ quires highly trained laboratory staff with access to specialized equipment and materials.

Laboratory diagnosis of YF is made by detection of either virus or virus antigen or genome (by enzymelinkedimmunosorbent assay (ELISA), polymerase chain reaction (PCR), or inoc‐ ulation virus into suckling mice, mosquitoes, or cell cultures), or by serology (immunoglo‐ bulin M capture ELISA), though cross-reactions with other flaviviruses complicate serologic methods of diagnosis. Postmortem examination of the liver reveals pathognomonic features of YF, including mid-zonal necrosis, and definitive diagnosis can be made by immunohisto‐ chemical staining of tissues (liver, heart, kidneys) for yellow fever antigen. It is important to note that liver biopsy should never be used for diagnosis during YF illness because of the risk for fatal hemorrhage at the biopsy site [67].

#### **14. Treatment**

In the absence of specific therapy, treatment of YF is chiefly supportive. Because most YF cases occur in areas lacking basic hospital facilities and where patients do not have access to modern intensive care. In the early stages of the disease, therapy should focus on controlling the fever and vomiting, relieving the headache and abdominal pains, and correcting the de‐ hydration. During the hepatorenal phase, suitable therapy based on careful patient monitor‐ ing should be administered to control the bleeding and manifestations associated with hepatorenal damage. Appropriate treatment to control malaria and secondary bacterial in‐ fections should be administered when necessary [64,65].
