**2.5 Rocio (ROCV)**

ROCV emerged as a cause of outbreaks of encephalitis in Brazil during 1975–1976. However, as another neglected arbovirus, there are less than 1,000 articles in PubMed (**Figure 3**), with no bibliometric studies.

After initial descriptions, sporadic reports have been identified; nevertheless, no additional outbreaks have been reported. ROCV is probably circulating among wild birds and transmitted by *Psorophora ferox* and *Aedes scapularis* [82, 83]. It has an incubation period of 7–14 days, and illness begins with headache, fever, nausea, and vomiting, sometimes with pharyngitis and conjunctivitis (**Table 2**). Meningitis or encephalitis follows in many, with altered mental state and cerebellar tremor. Convulsions are uncommon. The case fatality rate is about 10%. Death occurs in patients of all ages with neurological sequelae. Gait disturbances may appear in survivors [1, 2]. Some of these neglected viruses are commonly detected during dengue outbreaks, as with other arboviruses. Patients result negative for DENV and are investigated for multiple other flaviviruses and alphaviruses. Recent seroprevalence studies in animals detected ROCV in regions of Brazil, indicating risk for reemergence of this pathogen. A recent study identified ROCV RNA in samples from two human patients for whom dengue fever was clinically suspected but ruled out by laboratory findings. Then, such results suggest that testing for infrequent flavivirus infections should be considered, including ROCV [96, 97].

A group of maps showing the distribution by countries where neglected arboviruses have been reported (**Figure 6**). Theses maps do not necessarily reflect the real distribution, but just countries that have published cases or studies showing arboviral circulation. In the case of countries, such as Bolivia and Paraguay, is particularly curious that they have not reported most of the neglected arboviral pathogens, although have been described in most of their neighboring countries.
