Human Disease Caused by an Arbovirus Closely Related to Ilheus Virus: Report of Five Cases

Abstract

We report five cases of human disease caused by arbovirus in 5 patients from the State of São Paulo, Brazil, residing in the municipalities of Osasco, Atibaia, Guarujá, and the capital São Paulo, respectively. One of the patients resides in São Luis, capital of the State of Maranhão. The sites of infection probably were the states of Parana and Goiás, both in cave regions, the State of Amazonas, and Rondônia in two cases. Laboratory tests for malaria were negative and 1 patient showed a positive serum reaction for leptospirosis. Serum samples from the acute and convalescent phases were tested by hemagglutination inhibition, complement fixation, and neutralization in mice. Acute phase samples were inoculated into suckling mice by the intracerebral route. A close antigenic relationship was observed between the five agents isolated and the flavivirus Ilheus. Serologic tests demonstrated the absence of antibodies in all samples from the 5 patients during convalescence and even for more than 1 year after infection in 1 of them.

Nhumirim virus, a novel flavivirus isolated from mosquitoes from the Pantanal, Brazil

“…In Brazil, flaviviruses are involved in a large number of human disease cases comprised largely of dengue fever as well as sporadic local outbreaks of sylvatic yellow fever [2, 3]. Outbreaks caused by other flaviviruses, including Rocio virus (ROCV), as well as isolated human cases of infection with Saint Louis encephalitis virus (SLEV), Cacipacore virus (CPCV) and Ilheus virus (ILHV) have also been reported in the country [4–7]. Flaviviruses of eleven species have been isolated in Brazil, including Naranjal-like virus from a marsupial, Culex flavivirus from Culex mosquitoes, and a potential novel flavivirus recently isolated from ticks [8–10].…”

Ilheus VirusIsolate from a Human, Ecuador

“…Therefore, further sequencing of the NS5 region using flavivirus consensus primers FU1 and cFD3 ( 2 ) and the complete envelope (E) gene region, based on the complete open reading frame ILHV nucleotide sequence AY632539 ( 1 ), was conducted on FSE800, as well as a low-passage original 1944 isolate (R. Tesh, University of Texas Medical Branch [UTMB]), 2 mosquito isolates from Iquitos, Peru (R. Tesh, UTMB), and 2 human isolates from Brazil (CDC) ( 8 ) (Figure). There was 100% sequence identity among the 2 Brazilian and 2 Peruvian isolates at both gene regions.…”

Ilheus Virus Isolation in the Pantanal, West-Central Brazil

“…ILHV causes mainly asymptomatic infections in humans with rare reports of encephalitis throughout northern South America [4], [5]. Human infection with ILHV has been reported in Trinidad, Panama, Colombia, French Guyana, Brazil, Ecuador and Bolivia [6], [7], [8], [9], [10], [11], [12].…”