Yellow fever (YF) is a viral, vector-borne, haemorrhagic fever endemic in tropical regions of Africa and South America. The vaccine for YF is considered safe and effective, but intervention ...strategies need to be optimised; one of the tools for this is mathematical modelling. We refine and expand an existing modelling framework for Africa to account for transmission in South America. We fit to YF occurrence and serology data. We then estimate the subnational forces of infection for the entire endemic region. Finally, using demographic and vaccination data, we examine the impact of vaccination activities. We estimate that there were 109,000 (95% credible interval CrI 67,000-173,000) severe infections and 51,000 (95% CrI 31,000-82,000) deaths due to YF in Africa and South America in 2018. We find that mass vaccination activities in Africa reduced deaths by 47% (95% CrI 10%-77%). This methodology allows us to evaluate the effectiveness of vaccination and illustrates the need for continued vigilance and surveillance of YF.
Yellow fever virus (YFV) is a zoonotic arbovirus affecting both humans and non-human primates (NHP's) in Africa and South America. Previous descriptions of YF's seasonality have relied purely on ...climatic explanations, despite the high proportion of cases occurring in people involved in agriculture. We use a series of random forest classification models to predict the monthly occurrence of YF in humans and NHP's across Brazil, by fitting four classes of covariates related to the seasonality of climate and agriculture (planting and harvesting), crop output and host demography. We find that models captured seasonal YF reporting in humans and NHPs when they considered seasonality of agriculture rather than climate, particularly for monthly aggregated reports. These findings illustrate the seasonality of exposure, through agriculture, as a component of zoonotic spillover. Additionally, by highlighting crop types and anthropogenic seasonality, these results could directly identify areas at highest risk of zoonotic spillover.
Due to the risk of severe vaccine-associated adverse events, yellow fever vaccination in Brazil is only recommended in areas considered at risk for disease. From September 2008 through June 2009, two ...outbreaks of yellow fever in previously unvaccinated populations resulted in 21 confirmed cases with 9 deaths (case-fatality, 43%) in the southern state of Rio Grande do Sul and 28 cases with 11 deaths (39%) in Sao Paulo state. Epizootic deaths of non-human primates were reported before and during the outbreak. Over 5.5 million doses of yellow fever vaccine were administered in the two most affected states. Vaccine-associated adverse events were associated with six deaths due to acute viscerotropic disease (0.8 deaths per million doses administered) and 45 cases of acute neurotropic disease (5.6 per million doses administered). Yellow fever vaccine recommendations were revised to include areas in Brazil previously not considered at risk for yellow fever.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Every year, autochthonous cases of Plasmodium vivax malaria occur in low-endemicity areas of Vale do Ribeira in the south-eastern part of the Atlantic Forest, state of São Paulo, where Anopheles ...cruzii and Anopheles bellator are considered the primary vectors. However, other species in the subgenus Nyssorhynchus of Anopheles (e.g., Anopheles marajoara) are abundant and may participate in the dynamics of malarial transmission in that region. The objectives of the present study were to assess the spatial distribution of An. cruzii, An. bellator and An. marajoara and to associate the presence of these species with malaria cases in the municipalities of the Vale do Ribeira. Potential habitat suitability modelling was applied to determine both the spatial distribution of An. cruzii, An. bellator and An. marajoara and to establish the density of each species. Poisson regression was utilized to associate malaria cases with estimated vector densities. As a result, An. cruzii was correlated with the forested slopes of the Serra do Mar, An. bellator with the coastal plain and An. marajoara with the deforested areas. Moreover, both An. marajoara and An. cruzii were positively associated with malaria cases. Considering that An. marajoara was demonstrated to be a primary vector of human Plasmodium in the rural areas of the state of Amapá, more attention should be given to the species in the deforested areas of the Atlantic Forest, where it might be a secondary vector.
The recent reemergence of yellow fever virus (YFV) in Brazil has raised serious concerns due to the rapid dissemination of the virus in the southeastern region. To better understand YFV genetic ...diversity and dynamics during the recent outbreak in southeastern Brazil, we generated 18 complete and nearly complete genomes from the peak of the epidemic curve from nonhuman primates (NHPs) and human infected cases across the Espírito Santo and Rio de Janeiro states. Genomic sequencing of 18 YFV genomes revealed the estimated timing, source, and likely routes of yellow fever virus transmission and dispersion during one of the largest outbreaks ever registered in Brazil. We showed that during the recent epidemic, YFV was reintroduced from Minas Gerais to the Espírito Santo and Rio de Janeiro states multiple times between 2016 and 2019. The analysis of data from portable sequencing could identify the corridor of spread of YFV. These findings reinforce the idea that continued genomic surveillance strategies can provide information on virus genetic diversity and transmission dynamics that might assist in understanding arbovirus epidemics.
Arbovirus infections in Brazil, including yellow fever, dengue, zika, and chikungunya, result in considerable morbidity and mortality and are pressing public health concerns. However, our understanding of these outbreaks is hampered by the limited availability of genomic data. In this study, we investigated the genetic diversity and spatial distribution of YFV during the current outbreak by analyzing genomic data from areas in southeastern Brazil not covered by other previous studies. To gain insights into the routes of YFV introduction and dispersion, we tracked the virus by sequencing YFV genomes sampled from nonhuman primates and infected patients from the southeastern region. Our study provides an understanding of how YFV initiates transmission in new Brazilian regions and illustrates that genomics in the field can augment traditional approaches to infectious disease surveillance and control.
•Isolation of Orthoflavivirus ilheussense (ILHV) in Psorophora (Janthinosoma) ferox collected in cerrado biome of Brazil.•This is the first report of the circulation of ILHV in the state of Goiás, an ...arbovirus associated with febrile illness, which is often accompanied by encephalitis.•The strain is closely related to ILHV isolated in Belém (PA) during the dry season.•The ILHV detection in various regions from Brazil indicates the risk of the emergence of new diseases.
The Orthoflavivirus ilheusense (ILHV) is an arbovirus that was first isolated in Brazil in 1944 during an epidemiologic investigation of yellow fever. Is a member of the Flaviviridae family and it belongs to the antigenic complex of the Ntaya virus group. Psorophora ferox is the primary vector of ILHV and this study presents the isolation and phylogenetic analysis of ILHV in a pool of Ps. ferox collected in the state of Goiás in 2021. Viral isolation tests were performed on Vero cells and C6/36 clones. The indirect immunofluorescence test (IFI) was used to confirm the positivity of the sample. The positive sample underwent RT-qPCR, sequencing, and phylogenetic analysis. This is the first report of ILHV circulation in this municipality and presented close relationship between this isolate and another ILHV isolate collected in the city of Belém (PA).
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The current outbreak of yellow fever virus (YFV) that is afflicting Brazil since the end of 2016 probably originated from a re-introduction of YFV from endemic areas into the non-endemic Southeastern ...Brazil. However, the lack of genomic sequences from endemic regions hinders the tracking of YFV's dissemination routes. We assessed the origin and spread of the ongoing YFV Brazilian outbreak analyzing a new set of YFV strains infecting humans, non-human primates (NHPs) and mosquitoes sampled across five Brazilian states from endemic and non-endemic regions between 2015 and 2018. We found two YFV sub-clade 1E lineages circulating in NHP from Goiás state (GO), resulting from independent viral introductions into the Araguaia tributary river basin: while one strain from 2017 clustered intermingled with Venezuelan YFV strains from 2000, the other YFV strains sampled in 2015 and 2017 clustered with sequences of the current YFV outbreak in the Brazilian Southeastern region (named YFV
lineage), displaying the same molecular signature associated to the current YFV outbreak. After its introduction in GO at around mid-2014, the YFV
lineage followed two paths of dissemination outside GO, originating two major YFV sub-lineages: (1) the YFV
sub-lineage spread sequentially from the eastern area of Minas Gerais state to Espírito Santo and then to Rio de Janeiro states, following the Southeast Atlantic basin; (2) the YFV
sub-lineage spread from the southwestern area of Minas Gerais to the metropolitan region of São Paulo state, following the Paraná basin. These results indicate the ongoing YFV outbreak in Southeastern Brazil originated from a dissemination event from GO almost 2 years before its recognition at the end of 2016. From GO this lineage was introduced in Minas Gerais state at least two times, originating two sub-lineages that followed different routes toward densely populated areas. The spread of YFV outside endemic regions for at least 4 years stresses the imperative importance of the continuous monitoring of YFV to aid decision-making for effective control policies aiming the increase of vaccination coverage to avoid the YFV transmission in densely populated urban centers.
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•“A1” showed high levels of CCL3, CCL4, CCL2, CCL5, IL-1β, IL-15, IL-1Ra and G-CSF.•CCL3, CCL5, IL-15 and IL-1Ra presented AUC = 1.00 to discriminate “A1” from “C”.•VEGF presented ...AUC = 0.90 to discriminate “C(WT-YFV)” from other illnesses cases.•Serum biomarkers were complementary tools for differential diagnosis of YEL-AEFI cases.
In the present study, a range of serum biomarkers were quantified in suspected cases of adverse events following YF immunization (YEL-AEFI) to propose a reliable laboratorial algorithm to discriminate confirmed YEL-AEFI (“A1” class) from cases with other illnesses (“C” class). Our findings demonstrated that increased levels of CXCL8, CCL2, CXCL10, IL-1β, IL-6 and TNF-α were observed in YEL-AEFI (“A1” and “C” classes) as compared to primary vaccines without YEL-AEFI PV(day 3–28) and reference range (RR) controls. Notably, increased levels of CCL3, CCL4, CCL2, CCL5, IL-1β, IL-15, IL-1Ra and G-CSF were found in “A1” as compared to “C” class. Venn diagrams analysis allowed the pre-selection of biomarkers for further analysis of performance indices. Data demonstrated that CCL3, CCL5, IL-15 and IL-1Ra presented high global accuracy (AUC = 1.00) to discriminate “A1” from “C”. Decision tree was proposed with a reliable algorithm to discriminate YEL-AEFI cases according to cause-specific definitions with outstanding overall accuracy (91%). CCL3, CCL5, IL-15 and IL-1Ra appears as root attributes to identify “A1” followed by VEGF as branch nodes to discriminate Wild Type YFV infection (“C(WT-YFV)”) from cases with other illnesses (“C*”). Together, these results demonstrated the applicability of serum biomarker measurements as putative parameters towards the establishment of accurate laboratorial tools for complementary differential diagnosis of YEL-AEFI cases.
Objetivou-se determinar a prevalência de anticorpos inibidores da hemaglutinação para os arbovírus em aves selvagens em dois inquéritos sorológicos realizados entre abril e maio de 2007 e de 2008, em ...Salinópolis/PA. Foram capturadas 544 aves de 17 espécies diferentes, sendo nove residentes e oito migratórias, com uma taxa de coleta de sangue para isolamento de vírus de 64,3% (350/544) e para a realização do teste sorológico de inibição por hemaglutinação de 17,4% (95/544). Das aves que tiveram sangue colhido para isolamento não se conseguiu isolar nenhum vírus. Dos 95 soros nos quais foi realizado o teste de inibição de hemaglutinação, 14,7% foram reagentes para alfavírus, 9,5% para flavivírus e 7,4% para bunyavírus. Do total de reações positivas, 84,9% foram em aves migratórias e 15,1% em residentes. A proporção de aves positivas no teste, dentre as migratórias, foi de 31,5%, enquanto que nas residentes foi 18,2%, sem diferença estatisticamente significativa quando comparadas à proporção de aves positivas e o status da ave (p>0,05). Para os alfavírus, a espécie Pluvialis squatarola apresentou 28,6% de positividade, seguido da Arenaria interpres com 11,8%. Para os flavivírus, somente as espécies Sterna superciliares e a Calidris pusilla foram sorologicamente reagentes. Considerando os bunyavírus, a Arenaria interpres foi reagente em 5,9% para o vírus Oropouche. As aves migratórias demonstraram ser importantes amplificadores dos arbovírus pesquisados, embora os vírus não tenham sido isolados. Algumas espécies de aves têm maior capacidade de amplificação de alguns arbovírus do que outras. O isolamento do vírus a partir do sangue de aves selvagens é difícil, pois depende da colheita do sangue durante a fase de viremia. PALAVRAS CHAVES: arboviroses; aves migratórias; infecção.
The objective of this study was to determine the prevalence of hemagglutination-inhibition antibodies against arboviruses in wild birds in two serological surveys conducted in Salinopólis/Para State. ...A total of 544 birds of 17 species were captured, being nine resident and eight migratory. Blood was collected from 350 birds for virus isolation, but no virus was isolated. Of the 95 sera in which the hemagglutination inhibition test was performed, 14.7% were reactive to alphavirus, 9.5% to flavivirus and 7.4% to bunyavirus. Of the positive reactions, 84.9% occurred in migratory birds and 15.1% i resident birds. The proportions of positive reactions to the test among migratory and resident birds were 31.5% and 18.2%, respectively, which was not statistically different (p> 0.05). For alphaviruses, the species Pluvialis squatarola showed 28.6% positivity, followed by 11.8% in Arenaria interpres. For flaviviruses, only the species Sterna superciliares and Calidris pusilla were reactive to the hemagglutination inhibition test. Regarding the bunyavírus, the Arenaria interpres was 5.9% positive for the Oropouche virus. Migratory birds have proved to be important amplifiers of the arboviruses surveyed, although no viruses were isolated. Some bird species have greater amplification capacity of certain arboviruses than others. Virus isolation in wild birds is difficult, in view of the need of blood sampling in animals within the viremic period.
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