Lack of serological and molecular evidence of arbovirus infections in bats from Brazil

Abstract

Viruses are important agents of emerging zoonoses and are a substantial public health issue. Among emerging viruses, an important group are arboviruses, which are characterized by being maintained in nature in cycles involving hematophagous arthropod vectors and a wide range of vertebrate hosts. Recently, bats have received increasing attention as an important source for the emergence of zoonoses and as possible viral reservoirs. Among the arboviruses, there are many representatives of the genera Flavivirus and Alphavirus, which are responsible for important epidemics such as Dengue virus, Zika virus and Chikungunya virus. Due to the importance of analyzing potential viral reservoirs for zoonosis control and expanding our knowledge of bat viruses, this study aimed to investigate the presence of viruses of the Alphavirus and Flavivirus genera in bats. We analyzed serum, liver, lungs and intestine from 103 bats sampled in northeast and southern Brazil via Nested-PCR and the hemagglutination inhibition test. All samples tested in this study were negative for arboviruses, suggesting that no active or past infection was present in the captured bats. These data indicate that the bats examined herein probably do not constitute a reservoir for these viruses in the studied areas. Further studies are needed to clarify the role of bats as reservoirs and sources of infection of these viral zoonoses.

Can Bats Serve as Reservoirs for Arboviruses?

“…In 2018, Sotomayor-Bonilla and colleagues reported that liver and spleen samples from 12 Mexican bat species tested negative using pan-flavivirus NS5 primers [98]. A recent study in Brazil suggested a lack of arboviral circulation in bat populations, as 103 individuals from 9 species were tested for molecular and serologic evidence of alphavirus and flavivirus infection and all were negative [99]. Results of experimental infection of Egyptian rousette bats with WNV and of Angolan free-tailed bats ( Mops condylurus ) with Ntaya virus resulted in very low levels of viremia, while infection of African straw-colored fruit bats with Ntaya virus resulted in neither pathology nor detectable viremia [43].…”

Animals as potential reservoirs for dengue transmission: A systematic review

“… [ 57 ] Bats Costa Rica Puntarenas & Liberia Urban/rural 1998 12/53 (22.6); D1,2 PRNT; Tested for D1/2/3/4 Active outbreaks of dengue, all 4 serotypes have be isolated in the past 6 years of the study. [ 49 ] Ecuador Tena 3/10 (30); D2,3 Unknown Bats Mexico Cuitzmala River Basin, Jalisco Forest 2014 0/83 (Tested against flavivirus; NS5) DENV reported in humans [ 59 ] Bats Brazil São Jose ´ do Rio Preto, São Paulo State Urban/rural 2014–2017 0/64 (Tested against flavivirus; NS5) 0/46 HI; Tested for D1/2/3/4 High incidence of arbovirus infection in humans [ 50 ] Barreiras, Bahia State 0/39 (Tested against flavivirus; NS5) 0/27 Known occurrences of DENV Bats Columbia San Carlos & Ayapel , Córdoba & Sucre Urban/rural Before 2019 2/286 (0.7); D2 (NS5)* [ 45 ] Bats Singapore Unknown Urban/rural Before 2019 14/106 (13.2); D2 (NS1) Luciferase LIPS; Tested for D2 NS1 antigen only [ 54 ] Bats Australia Townsville, Northern Queensland Urban/rural 1954 4/17 (23.5); D1 Mouse protection test; Tested for D1 only Extensive epidemic from Dec 1953 – Mar 1954, sporadic cases from Dec 1954 – Nov 1955. …”

“…Among the urban/rural setting where bats were captured, there were 13.1% (136/1036) of bats that were dengue positive by serology while no bats (0/91) captured in the forest setting was positive by serology ( p < 0.05). There were 14 studies involving the urban/rural setting [ [44] , [45] , [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] ], 4 involving the forest setting [ 44 , 52 , 58 , 59 ]. Of which, 12 and 2 studies respectively were based in those settings exclusively.…”

Vaccines Targeted to Zoonotic Viral Infections in the Wildlife: Potentials, Limitations, and Future Directions

“…In this regard, anti-ZIKV antibodies with cross-reactivity to flaviviruses (yellow fever virus, West Nile virus, among others) were detected in bats from Uganda and Angola [70,71]. Although it is unclear how ZIKV could circulate in bat populations, it is noteworthy that bats represent a competent reservoirs in wildlife, with potential for amplifying flaviviruses and, contributing thus in the sylvatic transmission of ZIKV [72]. In contrast, Bittar et al [73] did not find serological and molecular evidence of past or latent arbovirus infections in captured bats from many areas of Brazil.…”

“…In contrast, Bittar et al [73] did not find serological and molecular evidence of past or latent arbovirus infections in captured bats from many areas of Brazil. Nevertheless, future studies are required to evaluate the role of bats as arbovirus reservoirs and to determine if these animal species are an important part of enzootic cycle of arboviruses [72].…”