Classic Dengue fever is characterized by high fever, severe headache, myalgia, arthralgia, malaise, nausea, vomiting, and a maculopapular skin rash. Ten percent of patients may develop cutaneous, subconjunctival, or retinal hemorrhages. This form is referred to as dengue hemorrhagic fever.
The ocular disease is bilateral in 75% of patients. In addition to subconjunctival and retinal hemorrhages, findings include anterior chamber and vitreous inflammation, retinal vasculitis, and vascular occlusion, retinitis, deep retinal spots/foveolitis, retinal pigment epithelial mottling, serous retinal detachment, and choroiditis.
"Hemorrhage, yellow-white lesions, and vasculitis are seen most often," Dr. Cunningham said.
"Interestingly, the clinical fundus picture in these patients does not look nearly as bad as the vascular leakage on fluorescein angiography," he said. "A great deal of leakage is present in these patients and it can be seen on ICGA images as well. Typically, retinal vasculitis does not leak on ICGA, but it can in patients with Dengue fever."
Chikungunya, an alphavirus and also a worldwide pathogen, was first reported in 1953 in East Africa in Tanzania and Mozambique. The disease now tends to be found mostly in Africa and East Asia, but recently has extended to South America, Caribbean nations, and the Southeastern United States. The name—which means "to walk bent over"—is characterized by severe arthritis.
The incubation period ranges from 2 to 14 days. The systemic manifestations in acute cases are similar—with patients complaining of fever, headache, low back pain, severe joint pain, myalgia, malaise, nausea, and vomiting. Patients who are severely affected suffer multiorgan failure, central nervous system involvement, and death.