RESUMO
A unique outbreak of Ross River virus (RRV) infection was reported in Fiji in 1979. In 2013, RRV seroprevalence among residents was 46.5% (362/778). Of the residents who were seronegative in 2013 and retested in 2015, 10.9% (21/192) had seroconverted to RRV, suggesting ongoing endemic circulation of RRV in Fiji.
Assuntos
Infecções por Alphavirus/diagnóstico , Ross River virus/imunologia , Infecções por Alphavirus/sangue , Infecções por Alphavirus/epidemiologia , Anticorpos Antivirais/sangue , Fiji/epidemiologia , Humanos , Ross River virus/isolamento & purificação , Estudos SoroepidemiológicosRESUMO
Zika and chikungunya viruses were first detected in Fiji in 2015. Examining surveillance and phylogenetic and serologic data, we found evidence of low-level transmission of Zika and chikungunya viruses during 2013-2017, in contrast to the major outbreaks caused by closely related virus strains in other Pacific Island countries.
Assuntos
Febre de Chikungunya/epidemiologia , Febre de Chikungunya/transmissão , Vírus Chikungunya , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/transmissão , Zika virus , Febre de Chikungunya/virologia , Vírus Chikungunya/classificação , Vírus Chikungunya/genética , Surtos de Doenças , Feminino , Fiji/epidemiologia , Humanos , Ilhas , Masculino , Filogenia , Vigilância da População , Fatores de Risco , Análise de Sequência de DNA , Estudos Soroepidemiológicos , Proteínas do Envelope Viral/genética , Zika virus/classificação , Zika virus/genética , Infecção por Zika virus/virologiaRESUMO
We investigated dengue and chikungunya virus antibody seroprevalence in French Polynesia during 2014-2015. Dengue virus seroprevalence was ≈60% among schoolchildren and >83% among the general population; chikungunya virus seroprevalence was <3% before and 76% after Zika virus emergence (2013). Dengue virus herd immunity may affect Zika virus infection and pathogenesis.
Assuntos
Anticorpos Antivirais/imunologia , Febre de Chikungunya/epidemiologia , Febre de Chikungunya/imunologia , Vírus Chikungunya/imunologia , Vírus da Dengue/imunologia , Dengue/epidemiologia , Dengue/imunologia , Adolescente , Adulto , Anticorpos Neutralizantes/imunologia , Febre de Chikungunya/história , Criança , Pré-Escolar , Dengue/história , História do Século XXI , Humanos , Pessoa de Meia-Idade , Testes de Neutralização , Polinésia/epidemiologia , Estudos Soroepidemiológicos , Adulto JovemRESUMO
Congenital Zika virus syndrome consists of a large spectrum of neurologic abnormalities seen in infants infected with Zika virus in utero. However, little is known about the effects of Zika virus intrauterine infection on the neurocognitive development of children born without birth defects. Using a case-control study design, we investigated the temporal association of a cluster of congenital defects with Zika virus infection. In a nested study, we also assessed the early childhood development of children recruited in the initial study as controls who were born without known birth defects,. We found evidence for an association of congenital defects with both maternal Zika virus seropositivity (time of infection unknown) and symptomatic Zika virus infection during pregnancy. Although the early childhood development assessment found no excess burden of developmental delay associated with maternal Zika virus infection, larger, longer-term studies are needed.
Assuntos
Desenvolvimento Infantil , Exposição Materna/efeitos adversos , Complicações Infecciosas na Gravidez/epidemiologia , Complicações Infecciosas na Gravidez/etiologia , Efeitos Tardios da Exposição Pré-Natal , Infecção por Zika virus/complicações , Infecção por Zika virus/epidemiologia , Zika virus , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Anormalidades Congênitas/epidemiologia , Anormalidades Congênitas/etiologia , Estudos Transversais , Feminino , Geografia Médica , História do Século XXI , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Razão de Chances , Avaliação de Resultados da Assistência ao Paciente , Polinésia/epidemiologia , Gravidez , Complicações Infecciosas na Gravidez/diagnóstico , Complicações Infecciosas na Gravidez/história , Vigilância em Saúde Pública , Adulto Jovem , Infecção por Zika virus/diagnóstico , Infecção por Zika virus/virologiaRESUMO
In French Polynesia, the first case of SARS-CoV-2 infection was detected on March 10th, 2020, in a resident returning from France. Between March 28th and July 14th, international air traffic was interrupted and local transmission of SARS-CoV-2 was brought under control, with only 62 cases recorded. The main challenge for reopening the air border without requiring travelers to quarantine on arrival was to limit the risk of re-introducing SARS-CoV-2. Specific measures were implemented, including the obligation for all travelers to have a negative RT-PCR test for SARS-CoV-2 carried out within 3 days before departure, and to perform another RT-PCR testing 4 days after arrival. Because of limitation in available medical staff, travelers were provided a kit allowing self-collection of oral and nasal swabs. In addition to increase our testing capacity, self-collected samples from up to 10 travelers were pooled before RNA extraction and RT-PCR testing. When a pool tested positive, RNA extraction and RT-PCR were performed on each individual sample. We report here the results of COVID-19 surveillance (COV-CHECK PORINETIA) conducted between July 15th, 2020, and February 15th, 2021, in travelers using self-collection and pooling approaches. We tested 5,982 pools comprising 59,490 individual samples, and detected 273 (0.46%) travelers positive for SARS-CoV-2. A mean difference of 1.17 Ct (CI 95% 0.93-1.41) was found between positive individual samples and pools (N = 50), probably related to the volume of samples used for RNA extraction (200 µL versus 50 µL, respectively). Retrospective testing of positive samples self-collected from October 20th, 2020, using variants-specific amplification kit and spike gene sequencing, found at least 6 residents infected by the Alpha variant. Self-collection and pooling approaches allowed large-scale screening for SARS-CoV-2 using less human, material and financial resources. Moreover, this strategy allowed detecting the introduction of SARS-CoV-2 variants of concern in French Polynesia.
Assuntos
Teste para COVID-19/métodos , COVID-19/diagnóstico , Programas de Rastreamento/métodos , Vigilância da População/métodos , Manejo de Espécimes/métodos , Viagem , COVID-19/epidemiologia , COVID-19/virologia , Teste para COVID-19/instrumentação , Epidemias/prevenção & controle , França/epidemiologia , Humanos , Polinésia/epidemiologia , Estudos Prospectivos , RNA Viral/genética , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , SARS-CoV-2/genética , SARS-CoV-2/fisiologia , Manejo de Espécimes/instrumentaçãoRESUMO
OBJECTIVES: In Fiji, autochthonous chikungunya virus (CHIKV) infection was first detected in March 2015. In a previous serosurvey conducted during October-November 2015, we reported a prevalence of anti-CHIKV IgG antibodies of 0.9%. In the present study, we investigated the seroprevalence of CHIKV two years after its emergence in Fiji. METHODS: Sera from 320 residents of Fiji recruited in June 2017, from the same cohort of individuals that participated in the serosurvey in 2015, were tested for the presence of IgG antibodies against CHIKV using a recombinant antigen-based microsphere immunoassay. RESULTS: Between 2015 and 2017, CHIKV seroprevalence among residents increased from 0.9% (3/333) to 12.8% (41/320). Of the participants with available serum samples collected in both 2015 and 2017 (n=200), 31 (15.5%) who were seronegative in 2015 had seroconverted to CHIKV in 2017. CONCLUSIONS: Our findings suggest that low-level transmission of CHIKV occurred during the two years following the emergence of the virus in Fiji. No CHIKV infection has been reported in Fiji since 2017, but due to the presumed low herd immunity of the population, the risk of CHIKV re-emergence is high. Consequently, chikungunya should be considered in the differential diagnosis of acute febrile diseases in Fiji.
Assuntos
Febre de Chikungunya/sangue , Febre de Chikungunya/epidemiologia , Vírus Chikungunya/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/sangue , Febre de Chikungunya/virologia , Vírus Chikungunya/classificação , Vírus Chikungunya/genética , Vírus Chikungunya/imunologia , Criança , Pré-Escolar , Feminino , Fiji/epidemiologia , Humanos , Imunidade Coletiva , Masculino , Pessoa de Meia-Idade , Soroconversão , Estudos Soroepidemiológicos , Adulto JovemRESUMO
It has been commonly assumed that Zika virus (ZIKV) infection confers long-term protection against reinfection, preventing ZIKV from re-emerging in previously affected areas for several years. However, the long-term immune response to ZIKV following an outbreak remains poorly documented. We compared results from eight serological surveys before and after known ZIKV outbreaks in French Polynesia and Fiji, including cross-sectional and longitudinal studies. We found evidence of a decline in seroprevalence in both countries over a two-year period following first reported ZIKV transmission. This decline was concentrated in adults, while high seroprevalence persisted in children. In the Fiji cohort, there was also a significant decline in neutralizing antibody titres against ZIKV, but not against dengue viruses that circulated during the same period.