Several recent studies in Virologica Sinica and other journals have highlighted the enormous international challenge of emerging arboviral diseases, such as Zika virus disease, dengue, and chikungunya (Islam et al., 2015; Maurice et al., 2015; Dai et al., 2016; Deng et al., 2016; Song et al., 2016; Wang Z et al., 2016; Xu et al., 2016; Zhang et al., 2016; Zhou et al., 2016). Rift Valley fever (RVF) is a mosquito-borne disease caused by the Rift Valley fever virus (RVFV), which causes high levels of mortality and morbidity in domesticated animals and mild to serious disease in humans. Since the virus was first described in Kenya in 1931 (Daubney et al., 1931), no extensive human outbreaks of this disease were reported until 1951, when approximately 20, 000 individuals were infected in South Africa (Mundel and Gear, 1951). Subsequently, there have been several RVF outbreaks with significant impact on human health in eastern Africa and the Arabian Peninsula (Meegan, 1979; CDC, 1998; Shoemaker et al., 2002; Woods et al., 2002) (http://www.who.int/csr/don/2007_05_09/en/). At present, RVFV is present or endemic in almost all African nations, as well as Saudi Arabia and Yemen in the Arabian Peninsula (Figure 1), and has the potential to expand to other regions.
RVFV can be transmitted by many mosquito species (mainly from the genera Aedes and Culex), as well as flies and ticks (Davies and Highton, 1980), and outbreaks of RVF are closely linked to heavy rainfall or flooding (Sindato et al., 2011). In addition, wildlife and livestock may play an important role in outbreaks in humans. Human cases are primarily caused by bites from infected mosquitoes or by direct contact with tissues or fluids from infected animals (Anyangu et al., 2010; Baba et al., 2016); In addition, vertical transmission has also been reported in mosquito vectors, ruminants, and humans (Arishi et al., 2006; Adam and Karsany, 2008). In humans, the disease can present with fever, headache, arthralgia and muscle pain, acute hepatitis, or hemorrhagic and neurological manifestations, and the fatality rate can reach 50% in patients with hemorrhagic complications (Swanepoel et al., 1979; Madani et al., 2003). Although there are three approved veterinary vaccines, no vaccines are available for human use (http://www.oie.int/manual-of-diagnostic-tests-and-vaccines-for-terrestrial-animals/).
Import of Rift Valley fever to China: a potential new threat?
- Published Date: 27 October 2016
Abstract: China has a large population, and its climate and the wide distribution of the mosquito vectors in south China are high risk factors for RVF outbreak. More importantly, once RVFV is introduced into permissive ecologies, it can become endemic, with the potential to spread into other non-endemic regions (Murithi et al., 2011). If there is an RVF outbreak in China, the disease may spread quickly to Southeast Asia and to other countries in Asia. Combined with the import of the Zika and yellow fever viruses this year (Su et al., 2016a; Wang L. et al., 2016), importation of arboviral pathogens poses a huge challenge for China. Therefore, all necessary measures should be taken to prevent and control RVF import and spread in China in the future.