RESUMO
We detected arenavirus RNA in 1.6% of 1,047 bats in Brazil that were sampled during 2007-2011. We identified Tacaribe virus in 2 Artibeus sp. bats and a new arenavirus species in Carollia perspicillata bats that we named Tietê mammarenavirus. Our results suggest that bats are an underrecognized arenavirus reservoir.
Assuntos
Arenavirus , Quirópteros , Animais , Arenavirus/genética , Brasil/epidemiologiaRESUMO
Decades after its discovery in East Africa, Zika virus (ZIKV) emerged in Brazil in 2013 and infected millions of people during intense urban transmission. Whether vertebrates other than humans are involved in ZIKV transmission cycles remained unclear. Here, we investigate the role of different animals as ZIKV reservoirs by testing 1723 sera of pets, peri-domestic animals and African non-human primates (NHP) sampled during 2013-2018 in Brazil and 2006-2016 in Côte d'Ivoire. Exhaustive neutralization testing substantiated co-circulation of multiple flaviviruses and failed to confirm ZIKV infection in pets or peri-domestic animals in Côte d'Ivoire (n=259) and Brazil (n=1416). In contrast, ZIKV seroprevalence was 22.2% (2/9, 95% CI, 2.8-60.1) in West African chimpanzees (Pan troglodytes verus) and 11.1% (1/9, 95% CI, 0.3-48.3) in king colobus (Colobus polycomos). Our results indicate that while NHP may represent ZIKV reservoirs in Africa, pets or peri-domestic animals likely do not play a role in ZIKV transmission cycles.
Assuntos
Animais Domésticos/virologia , Primatas/virologia , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/virologia , Zika virus , África , Animais , Brasil , Côte d'Ivoire , Humanos , Testes de Neutralização , Estudos Soroepidemiológicos , Infecção por Zika virus/transmissãoRESUMO
Among 713 equids sampled in northeastern Brazil during 2013-2018, West Nile virus seroprevalence was 4.5% (95% CI 3.1%-6.3%). Mathematical modeling substantiated higher seroprevalence adjacent to an avian migratory route and in areas characterized by forest loss, implying increased risk for zoonotic infections in disturbed areas.
Assuntos
Febre do Nilo Ocidental , Vírus do Nilo Ocidental , Animais , Brasil/epidemiologia , Ecologia , Estudos Soroepidemiológicos , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/veterináriaRESUMO
Although essential for control strategies, knowledge about transmission cycles is limited for Venezuelan equine encephalitis complex alphaviruses (VEEVs). After testing 1,398 bats from French Guiana for alphaviruses, we identified and isolated a new strain of the encephalitogenic VEEV species Tonate virus (TONV). Bats may contribute to TONV spread in Latin America.
Assuntos
Alphavirus , Quirópteros , Vírus da Encefalite Equina Venezuelana , Encefalomielite Equina Venezuelana , Animais , Guiana Francesa , CavalosRESUMO
Since 2013, the arthropod-borne Chikungunya virus (CHIKV) has cocirculated with the autochthonous Mayaro virus (MAYV) in Latin America. Both belong to the same alphavirus serocomplex, termed the Semliki Forest serocomplex. The extent of antibody cross-reactivity due to the antigenic relatedness of CHIKV and MAYV in commonly used serologic tests remains unclear. By testing 64 CHIKV- and 37 MAYV-specific sera from cohort studies conducted in Peru and Brazil, we demonstrate about 50% false-positive test results using commercially available enzyme-linked immunosorbent assays (ELISAs) based on structural antigens. In contrast, combining ELISAs for CHIKV and MAYV significantly increased positive predictive values (PPV) among all cohorts from 35.3% to 88.2% for IgM and from 61.3% to 96.8% for IgG (P < 0.0001). Testing of longitudinally collected CHIKV-specific patient sera indicated that ELISA specificity is highest for IgM testing at 5 to 9 days post-onset of symptoms (dpo) and for IgG testing at 10 to 14 dpo. IgG cross-reactivity in ELISA was asymmetric, occurring in 57.9% of MAYV-specific sera compared to 29.5% of CHIKV-specific sera. Parallel plaque reduction neutralization testing (PRNT) for CHIKV and MAYV increased the PPV from 80.0% to 100% (P = 0.0053). However, labor-intense procedures and delayed seroconversion limit PRNT for patient diagnostics. In sum, individual testing for CHIKV or MAYV only is prone to misclassifications that dramatically impact patient diagnostics and sero-epidemiologic investigation. Parallel ELISAs for both CHIKV and MAYV provide an easy and efficient solution to differentiate CHIKV from MAYV infections. This approach may provide a template globally for settings in which alphavirus coemergence imposes similar problems.IMPORTANCE Geographically overlapping transmission of Chikungunya virus (CHIKV) and Mayaro virus (MAYV) in Latin America challenges serologic diagnostics and epidemiologic surveillance, as antibodies against the antigenically related viruses can be cross-reactive, potentially causing false-positive test results. We examined whether widely used ELISAs and plaque reduction neutralization testing allow specific antibody detection in the scenario of CHIKV and MAYV coemergence. For this purpose, we used 37 patient-derived MAYV-specific sera from Peru and 64 patient-derived CHIKV-specific sera from Brazil, including longitudinally collected samples. Extensive testing of those samples revealed strong antibody cross-reactivity in ELISAs, particularly for IgM, which is commonly used for patient diagnostics. Cross-neutralization was also observed, albeit at lower frequencies. Parallel testing for both viruses and comparison of ELISA reactivities and neutralizing antibody titers significantly increased diagnostic specificity. Our data provide a convenient and practicable solution to ensure robust differentiation of CHIKV- and MAYV-specific antibodies.
Assuntos
Infecções por Alphavirus/imunologia , Anticorpos Antivirais/sangue , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Adolescente , Adulto , Alphavirus , Brasil , Vírus Chikungunya , Criança , Estudos de Coortes , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Peru , Adulto JovemRESUMO
An orthobunyavirus termed Fort Sherman virus (FSV) was isolated in 1985 from a febrile US soldier in Panama, yet potential animal reservoirs remained unknown. We investigated sera from 192 clinically healthy peri-domestic animals sampled in northeastern Brazil during 2014-2018 by broadly reactive RT-PCR for orthobunyavirus RNA, including 50 cattle, 57 sheep, 35 goats and 50 horses. One horse sampled in 2018 was positive (0.5%; 95% CI, 0.01-3.2) at 6.2 × 103 viral RNA copies/mL. Genomic comparisons following virus isolation in Vero cells and deep sequencing revealed high identity of translated amino acid sequences between the new orthobunyavirus and the Panamanian FSV prototype (genes: L, 98.8%; M, 83.5%; S, 100%), suggesting these viruses are conspecific. Database comparisons revealed even higher genomic identity between the Brazilian FSV and taxonomically unassigned Argentinian mosquito- and horse-derived viruses sampled in 1965, 1982 and 2013 with only 1.1% maximum translated amino acid distances across viral genes, suggesting the Argentinian viruses were also distinct FSV strains. The Panamanian FSV strain was an M gene reassortant relative to all Southern American FSV strains, clustering phylogenetically with Cache Valley virus (CVV). Mean dN/dS ratios among FSV genes ranged from 0.03 to 0.07, compatible with strong purifying selection. FSV-specific neutralizing antibodies occurred at relatively high end-point titres in the range of 1:300 in 22.0% of horses (11 out of 50 animals), 8.0% of cattle (4/50 animals), 7.0% of sheep (4/57 animals) and 2.9% of goats (1/35 animals). High specificity of serologic testing was suggested by significantly higher overall FSV-specific compared to CVV- and Bunyamwera virus-specific end-point titres (p = .009), corroborating a broad vertebrate host range within peri-domestic animals. Growth kinetics using mosquito-, midge- and sandfly-derived cell lines suggested Aedes mosquitos as potential vectors. Our findings highlight the occurrence of FSV across a geographic range exceeding 7,000 km, surprising genomic conservation across a time span exceeding 50 years, M gene-based reassortment events, and the existence of multiple animal hosts of FSV.
Assuntos
Infecções por Bunyaviridae/veterinária , Doenças dos Bovinos/virologia , Doenças das Cabras/virologia , Doenças dos Cavalos/virologia , Mosquitos Vetores/virologia , Orthobunyavirus/isolamento & purificação , Doenças dos Ovinos/virologia , Aedes/virologia , Animais , Brasil , Infecções por Bunyaviridae/virologia , Bovinos , Chlorocebus aethiops , Cabras , Cavalos , Especificidade de Hospedeiro , Orthobunyavirus/genética , Filogenia , Ovinos , Células Vero , ZoonosesRESUMO
Sloths are genetically and physiologically divergent mammals. Phleboviruses are major arthropod-borne viruses (arboviruses) causing disease in humans and other animals globally. Sloths host arboviruses, but virus detections are scarce. A phlebovirus termed Anhanga virus (ANHV) was isolated from a Brazilian Linnaeus's two-toed sloth (Choloepus didactylus) in 1962. Here, we investigated the presence of phleboviruses in sera sampled in 2014 from 74 Hoffmann's two-toed (Choloepus hoffmanni, n = 65) and three-toed (Bradypus variegatus, n = 9) sloths in Costa Rica by broadly reactive RT-PCR. A clinically healthy adult Hoffmann's two-toed sloth was infected with a phlebovirus. Viral load in this animal was high at 8.5 × 107 RNA copies/ml. The full coding sequence of the virus was determined by deep sequencing. Phylogenetic analyses and sequence distance comparisons revealed that the new sloth virus, likely representing a new phlebovirus species, provisionally named Penshurt virus (PEHV), was most closely related to ANHV, with amino acid identities of 93.1%, 84.6%, 94.7% and 89.0% in the translated L, M, N and NSs genes, respectively. Significantly more non-synonymous mutations relative to ANHV occurred in the M gene encoding the viral glycoproteins and in the NSs gene encoding a putative interferon antagonist compared to L and N genes. This was compatible with viral adaptation to different sloth species and with micro-evolutionary processes associated with immune evasion during the genealogy of sloth-associated phleboviruses. However, gene-wide mean dN/dS ratios were low at 0.02-0.15 and no sites showed significant evidence for positive selection, pointing to comparable selection pressures within sloth-associated viruses and genetically related phleboviruses infecting hosts other than sloths. The detection of a new phlebovirus closely-related to ANHV, in sloths from Costa Rica fifty years after and more than 3,000 km away from the isolation of ANHV confirmed the host associations of ANHV-related phleboviruses with the two extant species of two-toed sloths.
Assuntos
Infecções por Arbovirus/veterinária , Arbovírus/classificação , Phlebovirus/classificação , Bichos-Preguiça/virologia , Doenças Transmitidas por Vetores/veterinária , Animais , Infecções por Arbovirus/virologia , Arbovírus/genética , Arbovírus/isolamento & purificação , Brasil , Costa Rica , Geografia , Sequenciamento de Nucleotídeos em Larga Escala/veterinária , Phlebovirus/genética , Phlebovirus/isolamento & purificação , Filogenia , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Doenças Transmitidas por Vetores/virologia , Carga Viral/veterináriaRESUMO
The Zika virus outbreak in Latin America resulted in congenital malformations, called congenital Zika syndrome (CZS). For unknown reasons, CZS incidence was highest in northeastern Brazil; one potential explanation is that dengue virus (DENV)-mediated immune enhancement may promote CZS development. In contrast, our analyses of historical DENV genomic data refuted the hypothesis that unique genome signatures for northeastern Brazil explain the uneven dispersion of CZS cases. To confirm our findings, we performed serotype-specific DENV neutralization tests in a case-control framework in northeastern Brazil among 29 Zika virus-seropositive mothers of neonates with CZS and 108 Zika virus-seropositive control mothers. Neutralization titers did not differ significantly between groups. In contrast, DENV seroprevalence and median number of neutralized serotypes were significantly lower among the mothers of neonates with CZS. Supported by model analyses, our results suggest that multitypic DENV infection may protect from, rather than enhance, development of CZS.
Assuntos
Proteção Cruzada/imunologia , Vírus da Dengue/imunologia , Dengue/imunologia , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Complicações Infecciosas na Gravidez/epidemiologia , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/prevenção & controle , Zika virus/imunologia , Brasil/epidemiologia , Dengue/epidemiologia , Dengue/história , Vírus da Dengue/classificação , Vírus da Dengue/genética , Feminino , História do Século XX , História do Século XXI , Humanos , Recém-Nascido , Filogenia , Gravidez , Prevalência , Vigilância em Saúde Pública , Sorogrupo , Fatores de Tempo , Infecção por Zika virus/história , Infecção por Zika virus/transmissãoRESUMO
Screening of 533 bats for influenza A viruses showed subtype HL18NL11 in intestines of 2 great fruit-eating bats (Artibeus lituratus). High concentrations suggested fecal shedding. Genomic characterizations revealed conservation of viral genes across different host species, countries, and sampling years, suggesting a conserved cellular receptor and wide-ranging occurrence of bat influenza A viruses.
Assuntos
Quirópteros/virologia , Vírus da Influenza A , Infecções por Orthomyxoviridae/epidemiologia , Infecções por Orthomyxoviridae/virologia , Animais , Brasil/epidemiologia , Genoma Viral , Genômica/métodos , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Filogenia , Relação Estrutura-Atividade , Proteínas Virais/química , Proteínas Virais/genéticaRESUMO
In seroconversion panels obtained from patients from Brazil, diagnostic testing for Zika virus infection was improved by combining multiple antibody isotypes, techniques, and antigens, but sensitivity remained suboptimal. In contrast, chikungunya virus diagnostic testing was unambiguous. Recurrent recent arbovirus infections suggested by serologic data and unspecific symptoms highlight the need for exhaustive virologic testing.