Study of Kyasanur forest disease viremia, antibody kinetics, and virus infection in target organs of Macaca radiata

Primates and pandemics: A biocultural approach to understanding disease transmission in human and nonhuman primates

Investigations into zoonotic disease outbreaks have been largely epidemiological and microbiological, with the primary focus being one of disease control and management. Increasingly though, the human-animal interface has proven to be an important driver for the acquisition and transmission of pathogens in humans, and this requires syncretic bio-socio-cultural enquiries into the origins of disease emergence, for more efficacious interventions. A biocultural lens is imperative for the examination of primate-related zoonoses, for the human-primate interface is broad and multitudinous, involving both physical and indirect interactions that occur due to shared spaces and ecologies. I use the case example of a viral zoonotic epidemic that is currently endemic to India, the Kysanaur Forest Disease, to show how biocultural anthropology provides a broad and integrative perspective into infectious disease ecology and presents new insights into the determinants of disease outbreaks. Drawing on insights from epidemiology, political ecology, primate behavioral ecology and ethnoprimatology, this paper demonstrates how human-primate interactions and shared ecologies impact infectious disease spread between human and nonhuman primate groups.

Simplified visual detection of Kyasanur Forest Disease virus employing Reverse Transcriptase-Polymerase Spiral Reaction (RT-PSR)

Among recently prevalent tick-borne infections in India, Kyasanur Forest Virus Disease (KFD) is an important public health concern. During last decade the emergence of cases apart from endemic zone raised concern about case positivity. Early diagnosis is therefore very important in disease management and primary containment. This study, aimed to develop a simplified viral RNA extraction in combination to dry down format of novel isothermal assay for (Reverse Transcription- Polymerase Spiral reaction) specific and rapid identification of Kyasanur Forest Disease Virus targeting viral envelope gene. The one step method was optimized by magnetic bead based viral RNA extraction followed by isothermal RT-PSR assay in heat bath at 63⁰C for 60 minutes. Further, visual results interpretation was done by color change of Hydroxy Naphthol Blue dye. The detection limit of the assay was found 10 RNA copies/rxn with comparable to silica column based viral RNA combined real time qPCR. No cross reactivity was observed with other closely related flaviviruses. The assay was evaluated with clinical samples has shown >99% concordance between two methods. This is the first report of sample extraction coupled isothermal detection of KFD in a simplified manner without a need of any hi-end equipment. The assay developed here has potential to use as an alternate for field-based detection in resource limited settings for KFD.

Single-dose VSV-based vaccine protects against Kyasanur Forest disease in nonhuman primates

Kyasanur Forest disease virus (KFDV) is an endemic arbovirus in western India mainly transmitted by hard ticks of the genus Haemaphysalis. KFDV causes Kyasanur Forest disease (KFD), a syndrome including fever, gastrointestinal symptoms, and hemorrhages. There are no approved treatments, and the efficacy of the only vaccine licensed in India has recently been questioned. Here, we studied the protective efficacy of a vesicular stomatitis virus (VSV)-based vaccine expressing the KFDV precursor membrane and envelope proteins (VSV-KFDV) in pigtailed macaques. VSV-KFDV vaccination was found to be safe and elicited strong humoral and cellular immune responses. A single-dose vaccination reduced KFDV loads and pathology and protected macaques from KFD-like disease. Furthermore, VSV-KFDV elicited cross-reactive neutralizing immune responses to Alkhurma hemorrhagic fever virus, a KFDV variant found in Saudi Arabia.

A live-attenuated viral vector vaccine protects mice against lethal challenge with Kyasanur Forest disease virus

Kyasanur Forest disease virus (KFDV) is a tick-borne flavivirus endemic in India known to cause severe hemorrhagic and encephalitic disease in humans. In recent years, KFDV has spread beyond its original endemic zone raising public health concerns. Currently, there is no treatment available for KFDV but a vaccine with limited efficacy is used in India. Here, we generated two new KFDV vaccine candidates based on the vesicular stomatitis virus (VSV) platform. We chose the VSV-Ebola virus (VSV-EBOV) vector either with the full-length or a truncated EBOV glycoprotein as the vehicle to express the precursor membrane (prM) and envelope (E) proteins of KFDV (VSV-KFDV). For efficacy testing, we established a mouse disease model by comparing KFDV infections in three immunocompetent mouse strains (BALB/c, C57Bl/6, and CD1). Both vaccine vectors provided promising protection against lethal KFDV challenge in the BALB/c model following prime-only prime-boost and immunizations. Only prime-boost immunization with VSV-KFDV expressing full-length EBOV GP resulted in uniform protection. Hyperimmune serum derived from prime-boost immunized mice protected naïve BALB/c mice from lethal KFDV challenge indicating the importance of antibodies for protection. The new VSV-KFDV vectors are promising vaccine candidates to combat an emerging, neglected public health problem in a densely populated part of the world.

A pigtailed macaque model of Kyasanur Forest disease virus and Alkhurma hemorrhagic disease virus pathogenesis

Kyasanur Forest disease virus (KFDV) and the closely related Alkhurma hemorrhagic disease virus (AHFV) are emerging flaviviruses that cause severe viral hemorrhagic fevers in humans. Increasing geographical expansion and case numbers, particularly of KFDV in southwest India, class these viruses as a public health threat. Viral pathogenesis is not well understood and additional vaccines and antivirals are needed to effectively counter the impact of these viruses. However, current animal models of KFDV pathogenesis do not accurately reproduce viral tissue tropism or clinical outcomes observed in humans. Here, we show that pigtailed macaques (Macaca nemestrina) infected with KFDV or AHFV develop viremia that peaks 2 to 4 days following inoculation. Over the course of infection, animals developed lymphocytopenia, thrombocytopenia, and elevated liver enzymes. Infected animals exhibited hallmark signs of human disease characterized by a flushed appearance, piloerection, dehydration, loss of appetite, weakness, and hemorrhagic signs including epistaxis. Virus was commonly present in the gastrointestinal tract, consistent with human disease caused by KFDV and AHFV where gastrointestinal symptoms (hemorrhage, vomiting, diarrhea) are common. Importantly, RNAseq of whole blood revealed that KFDV downregulated gene expression of key clotting factors that was not observed during AHFV infection, consistent with increased severity of KFDV disease observed in this model. This work characterizes a nonhuman primate model for KFDV and AHFV that closely resembles human disease for further utilization in understanding host immunity and development of antiviral countermeasures.

Retrospective Study of Kyasanur Forest Disease and Deaths among Nonhuman Primates, India, 1957-2020

Kyasanur Forest disease (KFD) is a tickborne hemorrhagic disease affecting primates along the Western Ghats mountain range in India. Our retrospective study indicated that >3,314 monkey deaths attributed to KFD were reported in KFD-endemic states in India during 1957–2020. These data can help guide surveillance to protect animal and human health.

Assessing the importance of Molecular and Genetic perspectives in Prophesying the KFD transmission risk provinces in the Western Ghats, Kerala, INDIA in context with spatial distribution, Extensive genetic Diversity, and phylogeography

The deadly effects of KFD have been pointed in southern India; however, the infecting regions have been getting larger in recent epochs. People who live or work in regions where KFDV infected tick vectors are present are severely prone to procuring the infection. Being aware of tick vectors and infectious agents' geospatial location is vital to direct sustenance approaches to prevent and manage such infectious diseases as KFD. The present investigation has focussed on the spatial distribution, Extensive genetic Diversity, and phylogeography to forecast the probable KFD disease risk provinces in the Western Ghats. The statistical analysis for diversity indices and community comparison has been performed by using SPSS version 24.0.0 and R software version 3.4.2. The nucleotide sequences of the respective ticks and KFDV were retrieved from NCBI. The first strand of this investigation revealed that, around the world, the Indian province was found to exhibit a maximum range of diversity for tick vectors. The next strands prophesied the KFD transmission risk areas in the Western Ghats region, India, with computational spatial analysis and phylogeography. The final strand exposed the genetic diversity of the KFD virus and the tick vectors in terms of their spatial distribution worldwide.

Immunogenicity and protective efficacy of inactivated SARS-CoV-2 vaccine candidate, BBV152 in rhesus macaques

The COVID-19 pandemic is a global health crisis that poses a great challenge to the public health system of affected countries. Safe and effective vaccines are needed to overcome this crisis. Here, we develop and assess the protective efficacy and immunogenicity of an inactivated SARS-CoV-2 vaccine in rhesus macaques. Twenty macaques were divided into four groups of five animals each. One group was administered a placebo, while three groups were immunized with three different vaccine candidates of BBV152 at 0 and 14 days. All the macaques were challenged with SARS-CoV-2 fourteen days after the second dose. The protective response was observed with increasing SARS-CoV-2 specific IgG and neutralizing antibody titers from 3^rd-week post-immunization. Viral clearance was observed from bronchoalveolar lavage fluid, nasal swab, throat swab and lung tissues at 7 days post-infection in the vaccinated groups. No evidence of pneumonia was observed by histopathological examination in vaccinated groups, unlike the placebo group which exhibited interstitial pneumonia and localization of viral antigen in the alveolar epithelium and macrophages by immunohistochemistry. This vaccine candidate BBV152 has completed Phase I/II (NCT04471519) clinical trials in India and is presently in phase III, data of this study substantiates the immunogenicity and protective efficacy of the vaccine candidates.