Severe fever and thrombocytopenia syndrome virus infection: Considerations for vaccine evaluation of a rare disease

Analysis of cross neutralizing activity of antibodies from sera of severe fever with thrombocytopenia syndrome patients to deal with different genotype strains

Background

Severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) is a tick-borne virus that causes severe communicable fever with thrombocytopenia syndrome (SFTS) with an average case fatality rate of 10%. In the study, we aimed to identify the cross-neutralizing antibody (nAb) against different genotype strains from sera of SFTSV infected patients.

Methods

Firstly the genotype of SFTSV was identified by constructing a phylogenetic tree based on the M segments epidemic in the Jiaodong area of Shandong province, then different sera of subjects cross reactive with recombinant Gn (rGn-Fc) or recombinant Gc (rGc-Fc) of 0921 strain were examined. The levels of polyclonal nAbs from sera of 25 convalescents were measured by a pseudovirus-based neutralizing experiment.

Results

We found local endemic strains were mainly C2 and C3 isolates of SFTSV. 14 of 15 sera from donors reacted with 0921 rGn-Fc, and 9 of 15 sera from donors reacted with 0921 rGc-Fc. Cross nAbs were produced by 10 of 25 sera from donors during the period of 2019–2021. Among these, five nAbs (A2, A4, A5, L9, and L10) neutralized the pseudoviruses of HB29, Gangwon, HN13, HN20, SPL030A, and SD4 strains.

Conclusion

Our data suggested that epidemic strains showed relatively stable heredity. Some blood sources from patients produced cross nAbs that could neutralize all of the strains examined. These findings highlight the important role played by humoral immunity in combatting SFTSV.

Animal board invited review: Risks of zoonotic disease emergence at the interface of wildlife and livestock systems

The ongoing coronavirus disease 19s pandemic has yet again demonstrated the importance of the human-animal interface in the emergence of zoonotic diseases, and in particular the role of wildlife and livestock species as potential hosts and virus reservoirs. As most diseases emerge out of the human-animal interface, a better understanding of the specific drivers and mechanisms involved is crucial to prepare for future disease outbreaks. Interactions between wildlife and livestock systems contribute to the emergence of zoonotic diseases, especially in the face of globalization, habitat fragmentation and destruction and climate change. As several groups of viruses and bacteria are more likely to emerge, we focus on pathogenic viruses of the Bunyavirales, Coronaviridae, Flaviviridae, Orthomyxoviridae, and Paramyxoviridae, as well as bacterial species including Mycobacterium sp., Brucella sp., Bacillus anthracis and Coxiella burnetii. Noteworthy, it was difficult to predict the drivers of disease emergence in the past, even for well-known pathogens. Thus, an improved surveillance in hotspot areas and the availability of fast, effective, and adaptable control measures would definitely contribute to preparedness. We here propose strategies to mitigate the risk of emergence and/or re-emergence of prioritized pathogens to prevent future epidemics.

A new emerging pandemic of severe fever with thrombocytopenia syndrome (SFTS)

The aim of this study is to make aware every one of the deadliest diseases named severe fever with thrombocytopenia syndrome (SFTS). It has become the worldwide pandemic in recent few years. It is a kind of haemorrhagic fever, caused by SFTS virus (SFTSV), a novel phlebovirus of family Bunyaviridae. This syndrome is also a tick-borne zoonosis that means the virus transmitted from tick bite (having virus) into human body, i.e. infection spread from animals to humans and also transmitted from human to human. Epidemiological data of SFTS was collected to know the nature/symptoms of SFTSV. First case of this disease has been reported in China, followed by Japan, South korea, Taiwan, USA and many other countries. Vertebrates are the host of this disease and tick functions as a vector, where the virus can undergo brisk changes using gene mutation, homologous recombination and reassortments. The major symptoms of hemorrhagic fever are fever, thrombocytopenia, leucopenia and gastrointestinal abnormalities. Sometimes in very severe cases, full body organ failure may also take place and average death rate in humans is nearly 10 %. Old aged peoples are more prone to SFTSV infection. Apart from the fact of increasing SFTSV related health problems to humans, the pathogenesis of SFTS virus in human is not entirely understood and no treatment to this virus is still available. The simplest way to protect our self from this infection is to refrain from tick bite. Therefore, this disease has evolved to produce serious health issues to humans in various countries of world including china. This review discussing about causative agent, epidemiology, pathogenesis, diagnosis and treatment of SFTS. In order to control the spread of SFTSV, we have to stop the viral transmission or to protect the easily vulnerable population from tick bites, avoiding direct contact of infectious and also to use personal protective devices for SFTS patients. So, the weather conditions, mode of transmission and creation of new therapeutics like vaccines and drugs are the main areas of forthcoming research.

Challenges and solutions in the development of vaccines against emerging and neglected infectious diseases

Emerging and emergent infectious diseases (EIDs) represent a significant and growing cause of morbidity and mortality with increased potential for pandemics due to globalization and international trade. Challenges remain to the approach toward vaccine development for EIDs. This Special Feature explores areas related to vaccine development and testing, including unique challenges posed in the developing world. Vaccines against multiple pathogens spanning a number of viral families are explored with respect to past activities through to future commercialization. Cost drivers balanced against clinical need are discussed and unique challenges posed by rare diseases are considered.