ABSTRACT
Rift Valley fever (RVF) is a zoonotic viral disease transmitted by mosquitoes and causes abortion storms, fetal malformations, and newborn animal deaths in livestock ruminants. In humans, RVF can manifest as hemorrhagic fever, encephalitis, or retinitis. Outbreaks of RVF have been occurring in Africa since the early 20th century and continue to pose a threat to both humans and animals in various regions such as Africa, Madagascar, the Comoros, Saudi Arabia, and Yemen. The development of RVF vaccines is crucial in preventing mortality and morbidity and reducing the spread of the virus. While several veterinary vaccines have been licensed in endemic countries, there are currently no licensed RVF vaccines for human use. This review provides an overview of the existing RVF vaccines, as well as potential candidates for future studies on RVF vaccine development, including next-generation vaccines that show promise in combating the disease in both humans and animals.
ABSTRACT
Rift Valley fever (RVF) is a mosquito-borne zoonosis endemic to Africa and the Arabian Peninsula, which causes large outbreaks among humans and ruminants. Single dose vaccinations using live-attenuated RVF virus (RVFV) support effective prevention of viral spread in endemic countries. Due to the segmented nature of RVFV genomic RNA, segments of vaccine strain-derived genomic RNA could be incorporated into wild-type RVFV within co-infected mosquitoes or animals. Rationally designed vaccine candidate RVax-1 displays protective epitopes fully identical to the previously characterized MP-12 vaccine. Additionally, all genome segments of RVax-1 contribute to the attenuation phenotype, which prevents the formation of pathogenic reassortant strains. This study demonstrated that RVax-1 cannot replicate efficiently in orally fed Aedes aegypti mosquitoes, while retaining strong immunogenicity and protective efficacy in an inbred mouse model, which were indistinguishable from the MP-12 vaccine. These findings support further development of RVax-1 as the next generation MP-12-based vaccine for prevention of Rift Valley fever in humans and animals.
ABSTRACT
Introducción. Actualmente la infección por virus dengue constituye una de las arbovirosis más importantes y de amplia distribución en las regiones tropicales y subtropicales del planeta. Objetivo. Determinar la evolución del virus dengue circulante en el Ecuador durante el periodo 2000 a 2015. Diseño. Estudio no experimental, transversal, de tipo descriptivo y correlacional; Lugar. Unidades de salud del Ecuador. Participantes. Muestras tomadas a sospechosos de dengue con menos de 5 días de iniciada su enfermedad. Resultados. En el año 2000 se tuvo la presencia de los 4 serotipos, con predominio del DEN3 durante 2001 al 2006, coincidentes con los incrementos de casos del 2000, 2001 y 2005; en el año 2004 reapareció el virus DEN1 y los años siguientes su presencia predominó entre 2007 y 2012, coincidiendo con el incremento de casos en el 2010. Del año 2011 al 2015 se presentaron 3 virus circulantes a la vez (DEN1, DEN2 y DEN4), en 2014 y 2015 hubo la presencia del virus DEN3, con predominio del virus DEN2 en 2013 y 2014 y virus DEN1 en 2015; y ha sido la provincia del Guayas la de mayor relación con los virus. Conclusiones. La presencia de varios serotipos de virus dengue circulando a la vez y su permanencia se debería a otros factores que están influenciando en el comportamiento del virus, con una variabilidad de los cuatro serotipos. Se debe fortalecer la vigilancia molecular de la circulación de serotipos, genotipos y linajes del virus dengue.
Introduction: Nowadays, the dengue virus infection is one of the most important arboviroses in the world's tropical and subtropical regions. Objective: To determine the evolution of the dengue virus circulating in Ecuador during the period 2000-2015. Design: Non-experimental, transversal, descriptive and correlational study. Setting: Health units of Ecuador. Participants: The samples were taken from dengue suspects with less than 5 days from the beginning of the disease. Results: In 2000, the four serotypes were present, with prevalence of DEN3 during 2001-2006 coinciding with the increase of cases in 2000, 2001 and 2005; in 2004, the DEN1 virus reappeared and, during the following years, its presence predominated between 2007 and 2012, coinciding with the increase of cases in 2010. From 2011 to 2015 three circulating viruses were present at the same time (DEN1, DEN2 and DEN4); in 2014 and 2015, the DEN3 virus predominated; the predominance of the DEN2 virus was in 2013 and 2014, and of the DEN1 virus in 2015. The province of Guayas had the greatest relation with the virus. Conclusions: The presence and permanence of several serotypes of dengue virus circulating at the same time is due to other factors influencing the virus behavior and variability of the four serotypes. The molecular surveillance of the circulating serotypes, genotypes and dengue virus lineages should be strengthened.
