Mosquitoes as Vectors of Mycobacterium ulcerans Based on Analysis of Notifications of Alphavirus Infection and Buruli Ulcer, Victoria, Australia.

Alphavirus infections are transmitted by mosquitoes, but the mode of transmission for Mycobacterium ulcerans, which causes Buruli ulcer, is contested. Using notification data for Victoria, Australia, during 2017-2022, adjusted for incubation period, we show close alignment between alphavirus and Buruli ulcer seasons, supporting the hypothesis of mosquito transmission of M. ulcerans.

An improved alphaviruses-specific RT-qPCR facilitates monitoring and prevention of alphaviruses.

Molecular surveillance is vital for monitoring arboviruses, often employing genus-specific quantitative reverse-transcription polymerase chain reaction (RT-qPCR). Despite this, an overlooked chikungunya fever outbreak occurred in Yunnan province, China, in 2019 and false negatives are commonly encountered during alphaviruses screening practice, highlighting the need for improved detection methods. In this study, we developed an improved alphaviruses-specific RT-qPCR capable of detecting chikungunya virus, eastern equine encephalitis virus, western equine encephalitis virus, Venezuelan equine encephalitis virus, Sindbis virus, Mayaro virus, and Ross River virus with high sensitivity and specificity. The assay identified three chikungunya virus-positive cases out of 188 sera retrospectively. Later genetic characterization suggested that imported cases from neighboring countries may be responsible for the neglected chikungunya fever outbreak of 2019 in Yunnan. Our findings underscore the value of improved alphaviruses-specific RT-qPCR in bolstering alphaviruses surveillance and informing preventive strategies.

Advances in Alphavirus and Flavivirus Research.

Newly emerging viruses, primarily zoonotic or vector-borne, pose a persistent threat to public health and have led to outbreaks of global concern [...].

Co-circulation of two Alphaviruses in Burkina Faso: Chikungunya and O'nyong nyong viruses.

BACKGROUND: Chikungunya virus (CHIKV) and O'nyong nyong virus (ONNV) are phylogenetically related alphaviruses in the Semliki Forest Virus (SFV) antigenic complex of the Togaviridae family. There are limited data on the circulation of these two viruses in Burkina Faso. The aim of our study was to assess their circulation in the country by determining seroprevalence to each of the viruses in blood donor samples and by retrospective molecular and serological testing of samples collected as part of national measles and rubella surveillance. METHODOLOGY/PRINCIPAL FINDINGS: All blood donor samples were analyzed on the Luminex platform using CHIKV and ONNV E2 antigens. Patient samples collected during national measles-rubella surveillance were screened by an initial ELISA for CHIKV IgM (CHIKjj Detect IgM ELISA) at the national laboratory. The positive samples were then analyzed by a second ELISA test for CHIKV IgM (CDC MAC-ELISA) at the reference laboratory. Finally, samples that had IgM positive results for both ELISA tests and had sufficient residual volume were tested by plaque reduction neutralization testing (PRNT) for CHIKV and ONNV. These same patient samples were also analyzed by rRT-PCR for CHIKV. Among the blood donor specimens, 55.49% of the samples were positive for alphaviruses including both CHIKV and ONNV positive samples. Among patient samples collected as part of national measles and rubella surveillance, 3.09% were IgM positive for CHIKV, including 2.5% confirmed by PRNT. PRNT failed to demonstrate any ONNV infections in these samples. No samples tested by RT-qPCR. had detectable CHIKV RNA. CONCLUSIONS/SIGNIFICANCE: Our results suggest that CHIKV and ONNV have been circulating in the population of Burkina Faso and may have been confused with malaria, dengue fever or other febrile diseases such as measles or rubella. Our study underscores the necessity to enhance arbovirus surveillance systems in Burkina Faso.

Evolutionary Profile of Mayaro Virus in the Americas: An Update into Genome Variability.

The Mayaro virus (MAYV) is an arbovirus with emerging potential, though with a limited understanding of its epidemiology and evolution due to the lack of studies and surveillance. Here, we investigated 71 MAYV genome sequences from the Americas available at GenBank and characterized the phylogenetic relationship among virus strains. A phylogenetic analysis showed that sequences were grouped according to the genotypes L, D, and N. Genotype D sequences were closely related to sequences collected in adjacent years and from their respective countries, suggesting that isolates may have originated from circulating lineages. The coalescent analysis demonstrated similar results, indicating the continuous circulation of the virus between countries as well. An unidentified sequence from the USA was grouped with genotype D, suggesting the insertion of this genotype in the country. Furthermore, the recombination analysis detected homologous and three heterologous hybrids which presented an insertion into the nsP3 protein. Amino acid substitutions among sequences indicated selective pressure sites, suggesting viral adaptability. This also impacted the binding affinity between the E1-E2 protein complex and the Mxra8 receptor, associated with MAYV entry into human cells. These results provide information for a better understanding of genotypes circulating in the Americas.

Pathogenicity and virulence of O'nyong-nyong virus: A less studied Togaviridae with pandemic potential.

O'nyong-nyong virus (ONNV) is a neglected mosquito-borne alphavirus belonging to the Togaviridae family. ONNV is known to be responsible for sporadic outbreaks of acute febrile disease and polyarthralgia in Africa. As climate change increases the geographical range of known and potential new vectors, recent data indicate a possibility for ONNV to spread outside of the African continent and grow into a greater public health concern. In this review, we summarise the current knowledge on ONNV epidemiology, host-pathogen interactions, vector-virus responses, and insights into possible avenues to control risk of further epidemics. In this review, the limited ONNV literature is compared and correlated to other findings on mainly Old World alphaviruses. We highlight and discuss studies that investigate viral and host factors that determine viral-vector specificity, along with important mechanisms that determine severity and disease outcome of ONNV infection.

Molecular Epidemiology of Mayaro Virus among Febrile Patients, Roraima State, Brazil, 2018-2021.

We detected Mayaro virus (MAYV) in 3.4% (28/822) of febrile patients tested during 2018-2021 from Roraima State, Brazil. We also isolated MAYV strains and confirmed that these cases were caused by genotype D. Improved surveillance is needed to better determine the burden of MAYV in the Amazon Region.

Exposure dynamics of Ross River virus in horses - Horses as potential sentinels (a One Health approach).

Ross River virus (RRV), the most medically and economically important arbovirus in Australia, has been the most prevalent arbovirus infections in humans for many years. Infected humans and horses often suffer similar clinical symptoms. We conducted a prospective longitudinal study over a 3.5-year period to investigate the exposure dynamics of RRV in three foal cohorts (n = 32) born in a subtropical region of South East Queensland, Australia, between 2020 and 2022. RRV-specific seroconversion was detected in 56% (n = 18) of foals with a median time to seroconversion, after waning of maternal antibodies, of 429 days (95% CI: 294-582). The median age at seroconversion was 69 weeks (95% CI: 53-57). Seroconversion events were only detected between December and March (Southern Hemisphere summer) over the entire study period. Cox proportion hazards regression analyses revealed that seroconversions were significantly (p < 0.05) associated with air temperature in the month of seroconversion. Time-lags in meteorological variables were not significantly (p > 0.05) associated with seroconversion, except for relative humidity (p = 0.036 at 2-month time-lag). This is in contrast to research results of RRV infection in humans, which peaked between March and May (Autumn) and with a 0-3 month time-lag for various meteorological risk factors. Therefore, horses may be suitable sentinels for monitoring active arbovirus circulation and could be used for early arbovirus outbreak detection in human populations.

Most of the escaped farmed salmon entering a river during a 5-year period were infected with one or more viruses.

Disease interactions between farmed and wild populations have been poorly documented for most aquaculture species, in part due to the complexities to study this. Here, we tested 567 farmed Atlantic salmon escapees, captured in a Norwegian river during 2014-2018, for five viral infections that are prevalent in global salmonid aquaculture. Over 90% of the escapees were infected with one or more viruses. Overall prevalences were: 75.7% for piscine orthoreovirus (PRV-1), 43.6% for salmonid alphavirus (SAV), 31.2% for piscine myocarditis virus (PMCV), 1.2% for infectious pancreatic necrosis virus (IPNV) and 0.4% for salmon anaemia virus (ISAV). A significantly higher prevalence of PMCV infection was observed in immature compared to mature individuals. The prevalence of both SAV and PMCV infections was higher in fish determined by fatty acid profiling to be 'recent' as opposed to 'early' escapees that had been in the wild for a longer period of time. This is the first study to establish a time-series of viral infection status of escapees entering a river with a native salmon population. Our results demonstrate that farmed escapees represent a continuous source of infectious agents which could potentially be transmitted to wild fish populations.

Testing the intrinsic mechanisms driving the dynamics of Ross River Virus across Australia.

The mechanisms driving dynamics of many epidemiologically important mosquito-borne pathogens are complex, involving combinations of vector and host factors (e.g., species composition and life-history traits), and factors associated with transmission and reporting. Understanding which intrinsic mechanisms contribute most to observed disease dynamics is important, yet often poorly understood. Ross River virus (RRV) is Australia's most important mosquito-borne disease, with variable transmission dynamics across geographic regions. We used deterministic ordinary differential equation models to test mechanisms driving RRV dynamics across major epidemic centers in Brisbane, Darwin, Mandurah, Mildura, Gippsland, Renmark, Murray Bridge, and Coorong. We considered models with up to two vector species (Aedes vigilax, Culex annulirostris, Aedes camptorhynchus, Culex globocoxitus), two reservoir hosts (macropods, possums), seasonal transmission effects, and transmission parameters. We fit models against long-term RRV surveillance data (1991-2017) and used Akaike Information Criterion to select important mechanisms. The combination of two vector species, two reservoir hosts, and seasonal transmission effects explained RRV dynamics best across sites. Estimated vector-human transmission rate (average ß = 8.04x10-4per vector per day) was similar despite different dynamics. Models estimate 43% underreporting of RRV infections. Findings enhance understanding of RRV transmission mechanisms, provide disease parameter estimates which can be used to guide future research into public health improvements and offer a basis to evaluate mitigation practices.

On the prediction of SAV transmission among Norwegian aquaculture sites.

Pancreas Disease (PD) is a viral disease that affects Atlantic salmon (Salmo salar) in Norwegian, Scottish and Irish aquaculture. It is caused by salmonid alphavirus (SAV) and represents a significant problem in salmonid farming. Infection with SAV leads to reduced growth, mortality, product downgrading, and has a significant financial impact for the farms. The overall aim of this study is to evaluate the effect of various factors on the transmission of SAV and to create a predictive model capable of providing an early warning system for salmon farms within the Norwegian waters. Using a combination of publicly available databases, specifically BarentsWatch, and privately held PCR analyses a feature set consisting of 11 unique features was created based on the input parameters of the databases. An ensemble model was developed based on this feature set using XG-Boost, Ada-Boost, Random Forest and a Multilayer Perceptron. It was possible to successfully predict SAV transmission with 94.4% accuracy. Moreover, it was possible to predict SAV transmission 8 weeks in advance of a 'PD registration' at individual aquaculture salmon farming sites. Important predictors included well boat movement, environmental factors, proximity to sites with a 'PD registration' and seasonality.

Projeto Quantizika Humano ­ UFG / Human Quantizica Project ­ UFG

O Projeto Quantizika Humano, desenvolvido por docentes de várias unidades acadêmicas da Universidade Federal de Goiás (UFG), teve início em 2016, quando um grupo de pesquisadores composto por professores das áreas de biologia molecular e genética, epidemiologista e médico sanitarista, selecionaram pacientes que apresentavam sintomas semelhantes a dengue, inicialmente com a finalidade de rastrear aqueles que pudessem apresentar infecção pelo vírus da Zika. Durante o rastreamento molecular, e por meio de técnica própria desenvolvida na pesquisa, foram identificados também casos de infecção pelo vírus Mayaro (FERNANDES, M. 2019)

The Quantizica Humano Project, developed by professors from several academic units at the Federal University of Goiás (UFG), began in 2016, when a group of researchers composed of professors in the areas of molecular biology and genetics, an epidemiologist and a health doctor, selected patients who had symptoms similar to dengue, initially with the aim of tracking those who might have Zika virus infection. During the molecular screening, and by means of a proprietary technique developed in the research, cases of infection by the Mayaro virus were also identified (FERNANDES, M. 2019)

Mayaro virus in Latin America and the Caribbean / Virus Mayaro en América Latina y el Caribe / Vírus Mayaro na América Latina e Caribe

ABSTRACT Objectives. To assess the distribution of Mayaro virus (MAYV) in Latin America and the Caribbean and evaluate existing country-level MAYV surveillance mechanisms. Methods. Research was conducted from May 2018 through May 2019 to collect data from academic literature on Mayaro fever in Latin America and the Caribbean. PubMed, ClinicalKey, Scopus, Nature, SciELO, LILACS, and Google Scholar were searched for peer-reviewed journal articles, and data from health authorities, including the Pan American Health Organization (PAHO) and ministries of health, was also sought. MAYV-related publications published from 1954 through 2019 were screened. Publications that added to the overall understanding of MAYV, including its geographical and epidemiological distribution, were included in this report. Results. A total of 901 MAYV cases have been reported in humans in countries in Latin America and the Caribbean. Since its discovery in 1954 in Trinidad and Tobago, MAYV has been isolated from individuals living in Argentina, Bolivia, Brazil, Ecuador, French Guiana, Haiti, Mexico, Panama, Peru, and Venezuela. Of those 901 cases, 42 of them were reported exclusively by health authorities. In contrast, 843 confirmed and presumptive autochthonous cases and an additional 16 imported cases were identified in academic literature. No country-level surveillance mechanisms for MAYV were recorded in academic literature or by health authorities. Conclusions. This report demonstrates that MAYV surveillance efforts are limited in comparison to the virus's presence in Latin America and the Caribbean, highlighting the importance of enhancing arboviral surveillance systems in the affected countries.(AU)

RESUMEN Objetivos. Evaluar la distribución del virus Mayaro (MAYV) en América Latina y el Caribe y los mecanismos de vigilancia de nivel nacional. Métodos. Entre mayo de 2018 y mayo de 2019 se llevó a cabo una revisión bibliográfica sobre la fiebre de Mayaro en América Latina y el Caribe en las bases de datos PubMed, ClinicalKey, Scopus, Nature, SciELO, LILACS y Google Académico para identificar artículos en revistas arbitradas; también se revisó información suministrada por las autoridades sanitarias, entre ellas la Organización Panamericana de la Salud y los ministerios de salud. Se revisaron artículos relacionados con MAYV publicados entre 1954 y 2019. En este informe se incluyeron artículos que contribuyeran a la comprensión general sobre el MAYV, incluida su distribución geográfica y su epidemiología. Resultados. Se han reportado 901 casos de MAYV en seres humanos en 11 países de América Latina y el Caribe. Desde su descubrimiento en 1954 en Trinidad y Tobago, MAYV ha sido aislado de personas en Argentina, Bolivia, Brasil, Ecuador, Guayana Francesa, Haití, México, Panamá, Perú y Venezuela. De estos 901 casos, 42 fueron reportados exclusivamente por las autoridades sanitarias. A la vez, en la bibliografía se identificaron 844 casos autóctonos confirmados o presuntivos y 15 casos importados. A través de la bibliografía o las autoridades sanitarias no se identificaron mecanismos de vigilancia de nivel nacional para el MAYV. Conclusiones. En América Latina y el Caribe la vigilancia del MAYV es limitada en comparación con la presencia del virus en la región; es necesario mejorar los sistemas de vigilancia de arbovirus en los países afectados.(AU)

RESUMO Objetivo. Analisar a distribuição do vírus Mayaro (MAYV) na América Latina e Caribe e avaliar os mecanismos nacionais de vigilância. Métodos. Dados da literatura acadêmica sobre a febre Mayaro na América Latina e Caribe foram coletados de maio de 2018 a maio de 2019. Foram pesquisadas as bases de dados PubMed, ClinicalKey, Scopus, Nature, SciELO, LILACS e Google Acadêmico para identificar artigos em revistas revisadas por pares; também foram examinados dados de autoridades sanitárias, incluindo a Organização Pan-Americana da Saúde (OPAS), e dos ministérios de saúde. Artigos relacionados com MAYV publicados de 1954 a 2019 foram revisados. Este relatório incluiu artigos que contribuíssem para o entendimento geral do MAYV, com informações sobre distribuição geográfica e epidemiologia. Resultados. Foram registrados 901 casos de MAYV em humanos em 11 países da América Latina e do Caribe. Desde a sua descoberta em 1954 em Trinidad e Tobago, o MAYV foi isolado em indivíduos na Argentina, Bolívia, Brasil, Equador, Guiana Francesa, Haiti, México, Panamá, Peru e Venezuela. Desses 901 casos, 42 foram comunicados exclusivamente pelas autoridades sanitárias. Por sua vez, 844 casos autóctones confirmados ou suspeitos e 15 casos importados foram descritos na literatura. Nenhum mecanismo nacional de vigilância do MAYV foi identificado na literatura ou pelas autoridades sanitárias. Conclusões. Na América Latina e Caribe, a vigilância do MAYV é limitada em contraste com a presença do vírus na região; é importante melhorar os sistemas de vigilância desse arbovírus nos países afetados.(AU)

Momento de considerar otras arbovirosis luego del virus mayaro / Time to Consider Other Arbovirus Diseases after mayaro Virus

Introducción: En los últimos años, debido a los movimientos migratorios, se ha desarrollado una expansión de nuevas enfermedades, como chikungunya, zika, oropuche y mayaro. Caso clínico: Paciente que manifestaba síntomas de fiebre, cefalea y artralgias persistente. Después de un arduo estudio y eliminación de otras patologías se llega al diagnóstico de virus mayaro. El paciente residía en una zona nororiental del Perú. Se brindó tratamiento de soporte junto con hidratación, paracetamol 500 mg cada 8 horas y se indicó cita diaria para evaluación. El paciente evolucionó favorablemente a los pocos días. Conclusiones: La vigilancia, las pruebas y el control vectorial siguen siendo claves para prevenir la propagación de este tipo de virus. La posibilidad de que el virus mayaro se urbanice aún más. Se debe tener siempre en cuenta el diagnóstico diferencial de virus mayaro(AU)

Introduction: In recent years, due to migratory movements, an expansion of new diseases has developed, such as chikungunya, zika, oropuche and mayaro. Clinical case: Patient with the following symptoms: fever, headache and persistent arthralgia. After an arduous study and ruling out other possible diseases, we diagnose mayaro virus. The patient resided in a northeastern part of Peru. Supportive treatment was provided along with hydration; paracetamol 500 mg every 8 hours and daily appointment for evaluation was indicated. The patient evolved favorably within a few days. Conclusions: Surveillance, testing and vector control are still key to monitoring and preventing the spread of this type of virus. The possibility of mayaro virus becoming more urbanized is worthy of attention. The differential diagnosis of mayaro virus should always be considered(AU)

Respuesta a: Alfavirus tropicales artritogénicos / Response to: Tropical Arthritogenic Alphaviruses

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Will Mayaro virus be responsible for the next outbreak of an arthropod-borne virus in Brazil?

Abstract Mayaro virus is an alphavirus from the Togaviridae family and is transmitted mainly by Hemagogus mosquitoes. This virus circulates in high-density tropical forests or rural areas of Central and South America causing a disease characterized by high-grade fever, maculopapular skin rash and marked arthralgia that, in some patients, can persist for long periods after infection and may be misinterpreted as chikungunya. Although only a few outbreaks involving this virus have been reported, in the last years the number of Mayaro virus infections has increased in the central and northern regions of Brazil. In this review, we describe the reported prevalence of this infection over the years and discuss the circumstances that can contribute to the establishment of an urban mayaro virus epidemic in Brazil and the problems encountered with the specific diagnosis, especially the antigenic cross-reactivity of this pathogen with other viruses of the same family.

Mosquito-transmitted viruses - the great Brazilian challenge

ABSTRACT Arboviruses pose a serious threat to public health worldwide, overloading the healthcare system and causing economic losses. These viruses form a very diverse group, and in Brazil, arboviruses belonging to the families Flaviviridae and Togaviridae are predominant. Unfortunately, the number of arboviruses increases in proportion with factors such as deforestation, poor sanitation, climate changes, and introduction of new viruses like Chikungunya virus and Zika virus. In Brazil, dengue is endemic, along with the presence of other arboviruses. The situation is complicated by the scarcity of diagnostic infrastructure and the absence of approved vaccines for these diseases. Disease control, thus, relies solely on vector control. Therefore, enhanced clinical knowledge and improved general awareness about these arboviruses are indispensable to tackle diagnostic inadequacies.

Vigilancia de Fiebre Chikungunya / Chikungunya fever surveillance

La Fiebre Chikungunya es una enfermedad provocada por el virus Chikungunya (CHIKV) que pertenece al género Alphavirus (familia Togaviridae). A partir de 2004 se produjeron epidemias en África, Asia y Europa, con las que se inició una expansión global de la infección. Desde finales de 2013 la enfermedad está presente en las Américas, y no existe hasta el momento vacuna ni tratamiento con medicamentos antivirales contra esta enfermedad. El presente informe analiza sus vías de transmisión, manifestaciones clínicas, la situación epidemiológica internacional, argentina, y en Ciudad de Buenos Aires

Fiebre chikungunya. Manifestaciones reumáticas de una infección emergente en Europa / Chikungunya fever. Rheumatic manifestations of an emerging disease in Europe

La fiebre chikungunya es una enfermedad producida por un alfavirus perteneciente a la familiaTogaviridae, transmitida por miembros de diferentes especies del género Aedes: Aedes aegypti y Aedes albopictus (A. albopictus). Es endémica en África y Asia, ocasionando brotes epidémicos recurrentes. En 2007, surge de forma emergente en Europa transmitida por A. albopictus, asentado en el área mediterránea. Los primeros casos autóctonos detectados recientemente en las islas caribeñas suponen una seria amenaza de propagación al continente americano, libre hasta el momento de la enfermedad. Se manifiesta de forma aguda con fiebre, rash cutáneo y poliartritis. La mortalidad es baja, pero un porcentaje elevado de enfermos desarrollan una fase crónica definida por poliartritis persistente durante meses e incluso años. Una severa reacción inmunitaria de defensa con incremento de citocinas proinflamatorias es la responsable de la inflamación articular. El tratamiento es sintomático. No disponemos de terapia antiviral específica ni vacuna preventiva. Por ello, debemos profundizar en el estudio de la inmunopatogénesis, con el fin encontrar dianas terapéuticas más apropiadas (AU)

Chikungunya fever is a viral disease caused by an alphavirus belonging to the Togaviridae family, transmitted by several species of Aedes mosquitoes: Aedes aegypti and Aedes albopictus (A. albopictus). It is endemic in Africa and Asia with recurrent outbreaks. It is an emerging disease and cases in Europe transmitted by A. albopictus have been established in Mediterranean areas. The first autochthonous cases detected on the Caribbean islands suppose a serious threat of spreading disease to America, which so far has been disease free. Clinical symptoms begin abruptly with fever, skin rash and polyarthritis. Although mortality is low, a high percentage of patients develop a chronic phase defined by persistent arthritis for months or even years. A severe immune response is responsible for joint inflammation. The absence of specific treatment and lack of vaccine requires detailed studies about its immunopathogenesis in order to determine the most appropriate target (AU)